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Sample records for anhydrous molar ratios

  1. Investigation of High Molar Ratio Potassium Solution Used in Zinc-Rich Coatings

    Institute of Scientific and Technical Information of China (English)

    LI Sheng; WU Hang; YAN Rui

    2004-01-01

    High molar ratio potassium silicate solution used in zinc-rich water-base coatings was prepared by adding the nanosize SiO2 to the low molar ratio potassium silicate solution, and its microstructure was investigated by SEM and IR.Furthermore, the zinc-rich coatings was prepared by adding the zinc powders to this type of solution, and the properties of the coatings were evaluated. The test results show that the high molar ratio potassium silicate solution is the bonder of zinc-rich inorganic coatings with excellent property.

  2. Molar ratio S/In effect on properties of sprayed In2S3 films

    Science.gov (United States)

    Bouguila, Nourredine; Timoumi, Abdelmajid; Bouzouita, Hassen; Lacaze, Emmanuelle; Bouchriha, Habib; Rezig, Bahri

    2013-08-01

    We have studied the structural, morphological and optical properties of In2S3 layers deposited on glass substrate by the spray pyrolysis method with the molar ratio S/In varies from 1 to 4. The substrate temperature was maintained at 613 K. The characteristics of these films have been determined by X-ray diffraction (XRD), optical absorption-transmission and atomic force microscopy (AFM). Their structure is strongly dependent on the molar ratio. The deposit is mainly constituted by the β phase towards (4 0 0) direction. No characteristic peaks were observed for other impurities such as In2O3, S or In2(OH)3. The best crystallinity and surface morphology are obtained at molar ratio equal to 2.5. At this ratio, the crystallites coalesce and the local roughness is of the order of 1 nm. Optical transmission of 80% has been achieved in the visible spectrum. In2S3 band gap energy reached 2.63 eV from layers with x = 2 and deposited at Ts = 613 K.

  3. High-Temperature CO2 Sorption on Hydrotalcite Having a High Mg/Al Molar Ratio.

    Science.gov (United States)

    Kim, Suji; Jeon, Sang Goo; Lee, Ki Bong

    2016-03-09

    Hydrotalcites having a Mg/Al molar ratio between 3 and 30 have been synthesized as promising high-temperature CO2 sorbents. The existence of NaNO3 in the hydrotalcite structure, which originates from excess magnesium nitrate in the precursor, markedly increases CO2 sorption uptake by hydrotalcite up to the record high value of 9.27 mol kg(-1) at 240 °C and 1 atm CO2.

  4. Lipogenesis in Huh7 cells is promoted by increasing the fructose: Glucose molar ratio

    Institute of Scientific and Technical Information of China (English)

    Fernando; Windemuller; Jiliu; Xu; Simon; S; Rabinowitz; M; Mahmood; Hussain; Steven; M; Schwarz

    2016-01-01

    AIM: To determine whether hepatocyte lipogenesis, in an in vitro cell culture model, is modulated by adjusting culture media monosaccharide content and concentration.METHODS: Hepatocytes(Huh7), demonstrating glucose and fructose uptake and lipid biosynthesis, were incubated in culture media containing either glucose alone(0.65-0.72 mmol/L) or isosmolar monosaccharide(0.72 mmol/L) comprising fructose:glucose(F:G) molar ratios ranging from 0.58-0.67. Following a 24-h incubation, cells were harvested and analyzed for total protein, triglyceride(TG) and cholesterol(C) content. Significant differences(P < 0.05) among groups were determined using analysis of variance followed by Dunnett’s test for multiple comparisons.RESULTS: After a 24 h incubation period, Huh7 cell mass and viability among all experimental groups were not different. Hepatocytes cultured with increasing concentrations of glucose alone did not demonstrate a significant change either in C or in TG content. However, when the culture media contained increasing F:G molar ratios, at a constant total monosaccharideconcentration, synthesis both of C and of TG increased significantly [F:G ratio = 0.58, C/protein(μg/μg) = 0.13;F:G = 0.67, C/protein = 0.18, P < 0.01; F:G ratio = 0.58,TG/protein(μg/μg) = 0.06; F:G ratio = 0.67, TG/protein= 0.11, P < 0.01]. CONCLUSION: In an in vitro hepatocyte model, glucose or fructose plus glucose support total cell mass and lipogenic activity. Increasing the fructose:glucose molar ratio(but not glucose alone) enhances triglyceride and cholesterol synthesis. These investigations demonstrate fructose promotes hepatocellular lipogenesis, and they provide evidence supporting future, in vivo studies of fructose’s role in the development of hepatic steatosis and non-alcoholic fatty liver disease.

  5. Effect of ferrous/ferric ions molar ratio on reaction mechanism for hydrothermal synthesis of magnetite nanoparticles

    Indian Academy of Sciences (India)

    N Mizutani; T Iwasaki; S Watano; T Yanagida; H Tanaka; T Kawai

    2008-10-01

    Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were characterized by a scanning electron microscope, powder X-ray diffractometer, and superconducting quantum interference device (SQUID). At the molar ratio corresponding to the stoichiometric ratio in the synthesis reaction of magnetite from ferrous hydroxide and goethite, the nucleation of magnetite crystals progressed rapidly in an initial stage of the hydrothermal synthesis, resulting in formation of the magnetite nanoparticles having a smaller size and a lower crystallinity. On the other hand, at higher molar ratios, the particle size and crystallinity increased with increasing molar ratio because using surplus ferrous hydroxide the crystallites of magnetite nanoparticles grew up slowly under hydrothermal conditions according to the Schikorr reaction. The magnetite nanoparticles prepared under various molar ratios had good magnetic properties regardless of the molar ratio.

  6. Determination of Ca/P molar ratio in hydroxyapatite (HA) by X-ray fluorescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Scapin, Marcos A.; Guilhen, Sabine N.; Cotrim, Marycel E.B.; Pires, Maria Ap. F., E-mail: mascapin@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Hydroxyapatite (HA) is a mineral composed of calcium phosphate employed for endodontics, restorative dentistry and other applications in orthopedics and prosthesis. Additionally, this biomaterial is an inexpensive but efficient adsorbent for the removal of heavy metals and other unwanted species of contaminated liquid effluents. This is especially interesting when low-cost effective remediation is required. A Ca / P molar ratio of 1.667 is consistent with the theoretical Ca / P ratio for calcium hydroxyapatite with a compositional formula of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, which properties are well discussed in the literature. The aim of this work was to implement and validate a methodology for simultaneous determination of major and minor constituents in the hydroxyapatite (HA) as well as providing the Ca / P molar ratio. To accomplish these achievements, wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) was applied. This is a non-destructive technique that requires no chemical treatment, enabling fast chemical analysis in a wide variety of samples, with no hazardous waste being generated as a result of the process of determination. A standard reference material from NIST (SRM 1400 – Bone Ash) was used to validate the methodology for the determination of magnesium, phosphorus, potassium, calcium, iron, zinc, strontium and the Ca / P ratio in HA samples by WDXRF. The Z-score test was applied as a statistical tool and showed that the calculated values were of less than 1.8 for all the measured analytes. (author)

  7. Effects of the Optimised pH and Molar Ratio on Struvite Precipitation in Aqueous System

    Directory of Open Access Journals (Sweden)

    Edahwati Luluk

    2016-01-01

    Full Text Available Struvite (MgNH4PO4.6H2O is one of phosphate minerals, commonly forms into aqueous solutions. It can be precipitated as mineral deposits for optimization of phosphate recovery based on the pH optimum, molar ratio and temperature levels. This paper presents results of a study on the struvite precipitation under the influence of pH variation, at optimized molar ratio and temperature, which were calculated from an experimental design methodology. Based on the methodology, a laboratory prepared struvite, made by mixing solutions to NH4OH, MgCl2 and H3PO4 for a molar ratio of 1: 2: 1 in a 500 mL volume of batch stirred crystallizer at room temperature. The crystallization was done at 200 rpm and the pH variation was adjusted to 8, 9 and 10 with KOH for a time of 70 minutes. The resulting crystals were filtered and dried at room temperature for 48 h and subsequently stored for further analysis. Material characterisasion of the crystals was conducted using XRPD Rietveld method of mineralogical composition. SEM equipped by EDX was employed for investigation of morphology and elemental composition of the crystals obtained. During the experiment, struvite crystals were firstly nucleated and subsequently developed at major value. The increase in pH is assumed to convert some of the struvite phase into struvite (K and minor sylvite (KCl. It demonstrates that Visual MINTEQ can be employed to estimate the mineral formation out the synthetic solutions.

  8. Lipid concentration and molar ratio boundaries for the use of isotropic bicelles.

    Science.gov (United States)

    Beaugrand, Maïwenn; Arnold, Alexandre A; Hénin, Jérôme; Warschawski, Dror E; Williamson, Philip T F; Marcotte, Isabelle

    2014-06-03

    Bicelles are model membranes generally made of long-chain dimyristoylphosphatidylcholine (DMPC) and short-chain dihexanoyl-PC (DHPC). They are extensively used in the study of membrane interactions and structure determination of membrane-associated peptides, since their composition and morphology mimic the widespread PC-rich natural eukaryotic membranes. At low DMPC/DHPC (q) molar ratios, fast-tumbling bicelles are formed in which the DMPC bilayer is stabilized by DHPC molecules in the high-curvature rim region. Experimental constraints imposed by techniques such as circular dichroism, dynamic light scattering, or microscopy may require the use of bicelles at high dilutions. Studies have shown that such conditions induce the formation of small aggregates and alter the lipid-to-detergent ratio of the bicelle assemblies. The objectives of this work were to determine the exact composition of those DMPC/DHPC isotropic bicelles and study the lipid miscibility. This was done using (31)P nuclear magnetic resonance (NMR) and exploring a wide range of lipid concentrations (2-400 mM) and q ratios (0.15-2). Our data demonstrate how dilution modifies the actual DMPC/DHPC molar ratio in the bicelles. Care must be taken for samples with a total lipid concentration ≤250 mM and especially at q ∼ 1.5-2, since moderate dilutions could lead to the formation of large and slow-tumbling lipid structures that could hinder the use of solution NMR methods, circular dichroism or dynamic light scattering studies. Our results, supported by infrared spectroscopy and molecular dynamics simulations, also show that phospholipids in bicelles are largely segregated only when q > 1. Boundaries are presented within which control of the bicelles' q ratio is possible. This work, thus, intends to guide the choice of q ratio and total phospholipid concentration when using isotropic bicelles.

  9. Influence of variation in molar ratio on co-amorphous drug-amino acid systems

    DEFF Research Database (Denmark)

    Jensen, Katrine Birgitte Tarp; Larsen, Flemming Hofmann; Löbmann, Korbinian;

    2016-01-01

    Molecular interactions were investigated within four different co-amorphous drug-amino acid systems, namely indomethacin-tryptophan (Ind-Trp), furosemide-tryptophan (Fur-Trp), indomethacin-arginine (Ind-Arg) and furosemide-arginine (Fur-Arg). The co-amorphous systems were prepared by ball milling...... for 90min at different molar ratios and analyzed by XRPD and DSC. Interactions within the co-amorphous samples were evaluated based on the deviation between the actual glass transition temperature (Tg) and the theoretical Tg calculated by the Gordon-Taylor equation. The strongest interactions were...... observed in the 50mol% drug (1:1M ratio) mixtures, with the exception of co-amorphous Ind-Arg where the interactions within the 40mol% drug samples appear equally strong. A particularly large deviation between the theoretical and actual Tgs was observed within co-amorphous Ind-Arg and Fur-Arg systems...

  10. Role of reduced precursor and solvolytic reagent molar ratio on preparation and properties of ionogel

    Science.gov (United States)

    Gupta, Abhishek Kumar; Verma, Yogendra Lal; Singh, Manish Pratap; Singh, Rajendra Kumar

    2016-10-01

    In the present study, ionogels have been synthesized by immobilizing IL (1-ethyl-3-methylimidazolium tetrafluoroborate) in silica gel matrices using non-aqueous route. In this process, tetraethyl orho-silane (TEOS) as a precursor to silicon dioxide and formic acid as a solvolytic gelating reagent in reduced molar ratio 1:4 were used. We find that reduced molar concentration of formic acid results the formation of ionogels having less number of closed pores (totally isolated from their neighbours), larger density and stable monolithic form. TEM and SEM measurements are used to visualize the morphology of sample and closed pores present in the sample. N2-sorption measurement is used to measure the pore parameters of the silica matrices which shows the mesoporous structure. DSC and TGA results show the change in phase transition temperature and thermal stability of IL upon confinement in silica matrices. Moreover, ionic conductivity of bulk and confined IL is measured using impedance spectroscopy and it has been found that it increases with increasing the temperature as well as concentration of IL in ionogels. Apart from these characterization techniques, ionogels have been characterized using FTIR and fluorescence spectroscopy which exhibit the change in vibrational frequencies and fluorescence behaviour of confined IL.

  11. Variations of the BrO/SO2 molar ratios during the 2015 Cotopaxi eruption

    Science.gov (United States)

    Dinger, Florian; Arellano, Santiago; Battaglia, Jean; Bobrowski, Nicole; Galle, Bo; Hernandez, Stephen; Hidalgo, Silvana; Hörmann, Christoph; Lübcke, Peter; Platt, Ulrich; Ruiz, Mario; Warnach, Simon; Wagner, Thomas

    2016-04-01

    Cotopaxi volcano is located 50 km south of Quito, the capital of Ecuador. In case of a large eruption producing lahars, these may cause damage to the inhabited areas located to the south and north of the volcano and to the local water supply and other infrastructure. After almost 140 years of relative quiescence, increasing activity is observed in seismicity and gas emissions since May 2015. During August 2015 ash and gas emissions are recorded. Cotopaxi volcano is part of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) since 2009, thus the observations include the overall eruptive activity onset and its evolution. NOVAC regularly monitors the SO2 emissions of more than 30 volcanoes using scanning UV-spectrometers. Today, monitoring of volcanic SO2 emissions by UV-spectrometers is a widespread tool but its interpretation can be improved by additionally recording halogen/sulphur emission ratios. Recently, it has been shown that spectra from NOVAC instruments can also be used to retrieve the BrO/SO2 molar ratio by applying Differential Optical Absorption Spectroscopy (DOAS). We apply this new technique to analyse the plume composition of Cotopaxi volcano and will present time series of the BrO/SO2 ratios as monitored by the ground-based NOVAC instruments since March 2015. The SO2 column densities were below 6\\cdot1016 molec/cm^2 prior to May 2015 and up to 1.5\\cdot1018 molec/cm^2 between May and August 2015. For these periods, the BrO column densities were below the detection limit of 3\\cdot1013 molec/cm^2. After the phreatic explosions on 14.08.2015, SO2 column densities of up to 3\\cdot1018 molec/cm^2 and BrO column densities of up to 5\\cdot1014 molec/cm^2 were observed. Until December 2015 these SO2 column densities kept at about the same level but the BrO column densities increased up to 3\\cdot1014 molec/cm^2. After the phreatic explosions we find a detectable signal of BrO. Soon after the eruption the BrO/SO2 molar ratio was low as 1

  12. Synthesis of Trimethylolpropane Esters of Calophyllum Methyl Esters : Effect of Temperature and Molar Ratio

    Directory of Open Access Journals (Sweden)

    Yeti Widyawati

    2014-12-01

    Full Text Available Trimethylolpropane esters were synthesized by transesterification of calophyllum methyl esters and trimethylolpropane using a calcium oxide as the catalyst. The results showed that the optimal reaction conditions (temperature: 130 0C, reaction time: 5 h, reactant molar ratio: 3.9:1, catalyst amount 3%w/w, and formed  trimethylolpropane ester of 79.0% were obtained. The basic physicochemical properties of the trimethylolpropane esters were the following : kinematic viscosities of 56.40 cSt and 8.8 cSt at 40 0C and 100 0C,  viscosity index 193, flash point 218 0C and pour point -3 0C. So Methyl esters of fatty acids of would callophylum  methyl ester is good raw material for the synthesis of lubricating oils.

  13. Synthesis of aluminum nitride nanoparticles by a facile urea glass route and influence of urea/metal molar ratio

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhifang; Wan, Yizao [School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China); Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang, Jiangxi 330013 (China); Guo, Ruisong [School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China); Luo, Honglin, E-mail: hlluo@tju.edu.cn [School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China)

    2013-09-01

    Attention toward nanosized aluminum nitride (AlN) was rapidly increasing due to its physical and chemical characteristics. In this work, nanocrystalline AlN particles were prepared via a simple urea glass route. The effect of the urea/metal molar ratio on the crystal structure and morphology of nanocrystalline AlN particles was studied using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results revealed that the morphology and the crystal structure of AlN nanoparticles could be controlled by adjusting the urea/metal ratio. Furthermore, a mixture of Al{sub 2}O{sub 3} and h-AlN was detected at the urea/metal molar ratio of 4 due to the inadequate urea content. With increasing the molar ratio, the pure h-AlN was obtained. In addition, the nucleation and growth mechanisms of AlN nanocrystalline were proposed.

  14. Influence of Metallic Molar Ratio on the Electron Spin Resonance and Thermal Diffusivity of Zn–Al Layered Double Hydroxide

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    Abdullah Ahmed Ali Ahmed

    2013-01-01

    Full Text Available The coprecipitation method was used to prepare Zn–Al layered double hydroxide (Zn–Al–NO3-LDH at pH 7.5 and different Zn2+/Al3+ molar ratios of 2, 3, 4, 5, and 6. The elemental, structural, and textural properties of prepared samples were studied. The crystallinity of prepared LDH nanostructure decreases as Zn2+/Al3+ molar ratio increases. The electron spin resonance (ESR spectroscopy of different LDH samples showed new ESR spectra. These spectra were produced due to the presence of different phases with formed LDH such as ZnO phase and ZnAl2O4 spinel. At low Zn2+/Al3+ molar ratio, the ESR signals were produced from the presence of free nitrate anions in the LDH interlayer. Above Zn2+/Al3+ = 2, the ESR signals were attributed to the existence of ZnO phase and ZnAl2O4 spinel in the samples. Because the nuclear magnetic moment of 67Zn is lower than 27Al, the increasing in Zn2+/Al3+ molar ratio causes a reduction of the magnetic activity of ZnAl2O4 spinel. Thermal diffusivity versus in situ temperature showed nonlinear relation for different samples due to the changing in the water content of LDH as temperature increases. The dc conductivity of samples decreased as Zn2+/Al3+ molar ratio.

  15. Influence of magnesia-to-phosphate molar ratio on microstructures, mechanical properties and thermal conductivity of magnesium potassium phosphate cement paste with large water-to-solid ratio

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Biwan, E-mail: xubiwan@gmail.com [Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Ma, Hongyan, E-mail: mhy1103@gmail.com [Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Li, Zongjin [Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2015-02-15

    This paper describes the influence of the magnesia-to-phosphate (M/P) molar ratios ranging from 4 to 12, on the properties and microstructures of magnesium potassium phosphate cement (MKPC) pastes with a large water-to-solid ratio (w/s) of 0.50. The setting behavior, compressive strength, tensile bonding strength and thermal conductivity of the MKPC pastes, were investigated. The results show that an increase in the M/P ratio can slow down the setting reaction, and clearly degrade the mechanical strengths, but clearly improve the thermal conductivity of MKPC pastes. Furthermore, micro-characterizations including X-ray diffraction, scanning electron microscopy and thermogravimetric analysis, on the MKPC pastes reveal that a lower M/P ratio can facilitate better crystallization of the resultant magnesium potassium phosphate hexahydrate (MKP) and a denser microstructure. Moreover, strong linear correlations are found between the mechanical strengths and the MKP-to-space ratio, and between thermal conductivity and the volume ratio of the unreacted magnesia to the MKP. - Highlights: • Increase of M/P molar ratio causes clear mechanical degradations on MKPC pastes. • Thermal conductivity of MKPC pastes is improved with increase of M/P molar ratio. • Lower M/P ratio leads to better MKP crystallization and denser microstructure. • Strengths of MKPC pastes are linearly correlated to the MKP-to-space ratios. • Thermal conductivity is affected by the volume ratio of unreacted magnesia to MKP.

  16. Pulp/tooth ratio of mandibular first and second molars on panoramic radiographs: An aid for forensic age estimation

    Science.gov (United States)

    Shah, Palak H.; Venkatesh, Rashmi

    2016-01-01

    Objective: To determine and compare the accuracy of pulp/tooth ratio method in mandibular first and second molar teeth in forensic age estimation. Materials and Methods: A total 300 panoramic radiographs of the Gujarati population (187 males and 113 females) were studied. The measurements of Pulp Chamber Height (PCH) and Crown Root Trunk Height (CRTH) were performed on the mandibular first and second molar teeth. The acquired data was subjected to correlation and regression. Results: The pulp chamber crown root trunk height ratios (PCTHR) of both the first (r = −0.609) and second molars (r = −0.422) were significantly correlated with the age of the individual. Individual regression formulae were derived for both the teeth which were then used separately to calculate the age. The standard errors estimate (SEE) for the first and second molars were 8.84 years and 10.11 years, respectively. There was no statistically significant difference between chronological and calculated age by both the teeth (P = 1.000). Conclusion: The mandibular first and second molar is a potential tool for age estimation in forensic dentistry. The pulp/tooth ratio of both the teeth is a useful method for forensic age prediction with reasonable accuracy in the Gujarati population. PMID:27555734

  17. Phytate intake and molar ratios of phytate to zinc, iron and calcium in the diets of people in China

    NARCIS (Netherlands)

    Ma, G.; Li, Y.; Jin, Y.; Zhai, F.; Kok, F.J.; Yang, X.

    2007-01-01

    Objective: To assess the phytate intake and molar ratios of phytate to calcium, iron and zinc in the diets of people in China. Design: 2002 China Nationwide Nutrition and Health Survey is a cross-sectional nationwide representative survey on nutrition and health. The information on dietary intakes w

  18. Influnce of Stoichiometry and Molar Ratio of Barium Ferrite Thin Film Synthesized by Sol-gel on Alumina Substrate

    Institute of Scientific and Technical Information of China (English)

    AliGhasemi; M.R.Shams; A.Saatchi; M.Salehi; A.Hosseinpour

    2004-01-01

    Amorphous gels were processed with a varying Fe/Ba ratio of 11/5, 28/2, 10.5/1 in water and Solvent. Iron and barium nitrites with specific molar ratio was soloed in water and slovent at 60℃ for 3 hours untill a dark brown solution was prepared. The sols were introduced to substrate dropwise and spinning with 2000 rpm in 3 min was applied ; the work was repeated for 10 times and the samples were dried and sintered. The TGA analysis was used to identify the heating rate of the samples; at temperature of 1150℃ for one hour the final phase was attained, the thickness, uniformity, morphology and the composition were examined by SEM and XRD. The study shows that the fabrication barium ferrite film of the molar ratio of Fe/Ba=10.5/1 is much more suitable than other ratios.

  19. Influnce of Stoichiometry and Molar Ratio of Barium Ferrite Thin Film Synthesized by Sol-gel on Alumina Substrate

    Institute of Scientific and Technical Information of China (English)

    Ali Ghasemi; M.R. Shams; A.Saatchi; M.Salehi; A.Hosseinpour

    2004-01-01

    Amorphous gels were processed with a varying Fe/Ba ratio of 11/5, 28/2, 10.5/1 in water and Solvent. Iron and barium nitrites with specific molar ratio was solved in water and slovent at 60℃ for 3 hours untill a dark brown solution was prepared. The sols were introduced to substrate dropwise and spinning with 2000 rpm in 3 min was applied; the work was repeated for 10 times and the samples were dried and sintered. The TGA analysis was used to identify the heating rate of the samples; at temperature of 1150℃ for one hour the final phase was attained. the thickness, uniformity, morphology and the composition were examined by SEM and XRD. The study shows that the fabrication barium ferrite film of the molar ratio of Fe/Ba = 10.5/1 is much more suitable than other ratios.

  20. Silica-alumina molar ratio and some factors effect on the synthesis of zeolites from fly ash

    Institute of Scientific and Technical Information of China (English)

    SUN Yue-zhi; FU Ke-ming; ZHU Hong; ZHU Tian-lin

    2009-01-01

    In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, which is hydrothermally treated at about 104 ℃, and the liquid/solid ratio was controlled at 6:1. In order to control Si/AI molar ratio, SiO2 or Al2O3 powers were added to the fly ash. The results of XRD and SEM show that the alkali melted can activate fly ash and eliminate its quartz and mullite, along with the improvement of Si/AI molar ratio and alkalinity. In addition, zeolite Na-A changes into sodalite gradually, and nepheline is the synthesized intermediate product. Those results were discussed on the basis of a formation mechanism of zeolite from fly ash.

  1. Zn-Al layered double hydroxide prepared at different molar ratios: Preparation, characterization, optical and dielectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Abdullah Ahmed Ali [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Talib, Zainal Abidin, E-mail: zainalat@science.upm.edu.my [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zobir bin Hussein, Mohd [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zakaria, Azmi [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2012-07-15

    The co-precipitation method was used to prepare Zn-Al-NO{sub 3}-LDH at different Zn{sup 2+}/Al{sup 3+} molar ratios (2, 3, 4, 5 and 6) and pH value of 7.5. The structure, textural, composition and morphological properties were investigated using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) and scanning electron microscope (SEM), respectively. The crystallinity of LDH samples were found to improve as molar ratio decreased which is attributed to the distortion of the hydroxide layers networks of the LDH crystal by the larger difference in ionic radii of Zn{sup 2+} and Al{sup 3+}. The optical band gap energy of LDH samples were evaluated using absorbance data from UV-Vis-NIR Diffuse reflectance spectroscopy. Band gaps were affected by the variation of the Zn{sup 2+}/Al{sup 3+} molar ratio is due to the formation of the low crystalline phases (ZnO and ZnAl{sub 2}O{sub 4}). The water molecules and anionic NO{sub 3}{sup -} in the LDH interlayer were responsible for the generation of the dielectric response. This response can be described by an anomalous low frequency dispersion using the second type of Universal Power Law. The dominance of ZnO dipoles and charge carriers (NO{sub 3}{sup -} ions) in the dielectric relaxation increases with the increasing molar ratio. - Graphical abstract: (a) Schematic diagram of Zn-Al- NO{sub 3}-LDH shows the LDH structure, (b) Kubelka-Munk transformed reflectance spectra and c. The dielectric constant versus frequency of Zn-Al- NO{sub 3}-LDH samples. Highlights: Black-Right-Pointing-Pointer Zn-Al-NO{sub 3}-LDH was prepared at different Zn{sup 2+}/Al{sup 3+} molar ratios (2, 3, 4, 5 and 6). Black-Right-Pointing-Pointer The crystallinity of LDH phase decreased with increase of Zn{sup 2+}/Al{sup 3+} molar ratio. Black-Right-Pointing-Pointer The optical band gaps of LDH samples have been measured. Black-Right-Pointing-Pointer Dielectric response of LDH can be described by anomalous low

  2. Colloidal Synthesis And Characterization Of Cdse Quantum Dots Role Of CdSe Molar Ratio And Temperature

    Directory of Open Access Journals (Sweden)

    Hakan Aydamp305n

    2015-08-01

    Full Text Available Semiconductor Cadmium selenide CdSe Quantum Dots QDs were synthesized via colloidal chemistry method at moderately lower growth temperatures. Optical absorption and photoluminescence PL spectroscopy techniques were used to characterize the optical properties of CdSe QDs. Optical properties of colloidal CdSe QDs were successfully controlled by changing the initial CdSe molar ratios and temperature. Optical absorption and PL spectrum both showed gradual red shift with increasing CdSe molar ratio and temperature. High-resolution transmission electron microscopy HRTEM technique were used to study the structural properties of CdSe QDs. Full width at half maximum FWHM values obtained from the emission spectrums were helped to prove the narrow size distribution which coincides with the matching results of HRTEM images and theoretical calculations.

  3. Fluorescent probes sensitive to changes in the cholesterol-to-phospholipids molar ratio in human platelet membranes during atherosclerosis

    Science.gov (United States)

    Posokhov, Yevgen

    2016-09-01

    Environment-sensitive fluorescent probes were used for the spectroscopic visualization of pathological changes in human platelet membranes during cerebral atherosclerosis. It has been estimated that the ratiometric probes 2-(2‧-hydroxyphenyl)-5-phenyl-1,3,4-oxadiazole and 2-phenyl-phenanthr[9,10]oxazole can detect changes in the cholesterol-to-phospholipids molar ratio in human platelet membranes during the disease.

  4. Can the Follicle-Crown Ratio of the Impacted Third Molars be a Reliable Indicator of Pathologic Problem?

    Science.gov (United States)

    Haghanifar, Sina; Moudi, Ehsan; Seyedmajidi, Maryam; Mehdizadeh, Mohammad; Nosrati, Kamran; Abbaszadeh, Naghi; Bijani, Ali; Ghorbani, Hakimeh

    2014-01-01

    Statement of the Problem: The presence of impacted third molars in the jaws is a common finding in the routine dental examination of patients. Concerning the odontogenic components of the dental follicle, it can be the origin of different types of odontogenic cysts and tumors. Purpose: The aim of this study was to find feasible radiographic criteria to help differentiate between normal and pathological dental follicles. Materials and Method: 134 asymptomatic impacted third molars were recruited in this study. Then, based on the radiographic measurements, the ratio between the diameter of the dental follicle and the mesiodistal width of the tooth crown was calculated. After surgical removal of impacted third molars, the related dental follicles were evaluated histopathologically. Statistical analyses were performed by adopting chi-square test, t-test, receiver oprating characteristic (ROC) curve, and logistic regression using SPSS-19 software. Results: The mean ratio of the dental follicle’s diameter to the mesiodistal width, in the normal and cystic follicle group was 1.18 ± 0.07 and 1.18 ± 0.08, respectively. There was no statistically significant difference between this ratio and the histopathological evaluation. Based on the logistic regression analysis, only the age >20 years and inflammation had predictive value in identifying cystic changes in dental follicle. Conclusion: According to the findings of the current study, the ratio of dental follicle diameter to the mesiodistal width of the teeth cannot not be employed as a diagnostic index to differentiate between normal and pathological dental follicle. PMID:25469358

  5. The effect of different molar ratios of ZnO on characterization and photocatalytic activity of TiO2/ZnO nanocomposite

    OpenAIRE

    Shahram Moradi; Parviz Aberoomand-Azar; Sanaz Raeis-Farshid; Saeed Abedini-Khorrami; Mohammad Hadi Givianrad

    2016-01-01

    The TiO2/ZnO nanocomposite as a photocatalyst was prepared with different molar ratios of ZnO using the sol–gel method. The structures and properties were recognized with Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) methods. The XRD study exhibited that the crystallization behavior of the nanocomposites was associated with the molar ratios of ZnO. The SEM images indicated that with increasing the molar ratio of TiO2/ZnO unti...

  6. Co-production of acetone and ethanol with molar ratio control enables production of improved gasoline or jet fuel blends.

    Science.gov (United States)

    Baer, Zachary C; Bormann, Sebastian; Sreekumar, Sanil; Grippo, Adam; Toste, F Dean; Blanch, Harvey W; Clark, Douglas S

    2016-10-01

    The fermentation of simple sugars to ethanol has been the most successful biofuel process to displace fossil fuel consumption worldwide thus far. However, the physical properties of ethanol and automotive components limit its application in most cases to 10-15 vol% blends with conventional gasoline. Fermentative co-production of ethanol and acetone coupled with a catalytic alkylation reaction could enable the production of gasoline blendstocks enriched in higher-chain oxygenates. Here we demonstrate a synthetic pathway for the production of acetone through the mevalonate precursor hydroxymethylglutaryl-CoA. Expression of this pathway in various strains of Escherichia coli resulted in the co-production of acetone and ethanol. Metabolic engineering and control of the environmental conditions for microbial growth resulted in controllable acetone and ethanol production with ethanol:acetone molar ratios ranging from 0.7:1 to 10.0:1. Specifically, use of gluconic acid as a substrate increased production of acetone and balanced the redox state of the system, predictively reducing the molar ethanol:acetone ratio. Increases in ethanol production and the molar ethanol:acetone ratio were achieved by co-expression of the aldehyde/alcohol dehydrogenase (AdhE) from E. coli MG1655 and by co-expression of pyruvate decarboxylase (Pdc) and alcohol dehydrogenase (AdhB) from Z. mobilis. Controlling the fermentation aeration rate and pH in a bioreactor raised the acetone titer to 5.1 g L(-1) , similar to that obtained with wild-type Clostridium acetobutylicum. Optimizing the metabolic pathway, the selection of host strain, and the physiological conditions employed for host growth together improved acetone titers over 35-fold (0.14-5.1 g/L). Finally, chemical catalysis was used to upgrade the co-produced ethanol and acetone at both low and high molar ratios to higher-chain oxygenates for gasoline and jet fuel applications. Biotechnol. Bioeng. 2016;113: 2079-2087. © 2016 Wiley

  7. Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio

    Science.gov (United States)

    Priolisi, Ornella; Fabrizi, Alberto; Deon, Giovanna; Bonollo, Franco; Cattini, Stefano

    2016-01-01

    In this work the morphology evolution of Au nanoparticles (AuNPs), obtained by direct reduction, was studied as a function of time, temperature, and Au(III)/sodium ascorbate molar ratio. The NPs morphology was examined by transmission electron microscope with image analysis, while time evolution was investigated by visible and near-infrared absorption spectroscopy and dynamic light scattering. It is found that initially formed star-like NPs transform in more spheroidal particles and the evolution appears more rapid by increasing the temperature while a large amount of reducing agent prevents the remodeling of AuNPs. An explication of morphology evolution is proposed.

  8. Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio

    Energy Technology Data Exchange (ETDEWEB)

    Priolisi, Ornella, E-mail: ornella.priolisi@depretto.gov.it [ITIS “De Pretto” (Italy); Fabrizi, Alberto, E-mail: fabrizi@gest.unipd.it [University of Padova, Department of Management and Engineering (Italy); Deon, Giovanna, E-mail: giovanna.deon@depretto-vi.it [ITIS “De Pretto” (Italy); Bonollo, Franco, E-mail: bonollo@gest.unipd.it [University of Padova, Department of Management and Engineering (Italy); Cattini, Stefano, E-mail: stefano.cattini@unimore.it [University of Modena and Reggio Emilia, Department of Engineering Enzo Ferrari (Italy)

    2016-01-15

    In this work the morphology evolution of Au nanoparticles (AuNPs), obtained by direct reduction, was studied as a function of time, temperature, and Au(III)/sodium ascorbate molar ratio. The NPs morphology was examined by transmission electron microscope with image analysis, while time evolution was investigated by visible and near-infrared absorption spectroscopy and dynamic light scattering. It is found that initially formed star-like NPs transform in more spheroidal particles and the evolution appears more rapid by increasing the temperature while a large amount of reducing agent prevents the remodeling of AuNPs. An explication of morphology evolution is proposed.

  9. Corrosion characteristics of Al-Si-Mg/SiC{sub p} composites with varying Si/Mg molar ratio in neutral chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Escalera-Lozano, R.; Pech-Canul, M.I. [Cinvestav Saltillo (Mexico); Pech-Canul, M.A.; Quintana, P. [Departamento de Fisica Aplicada, Merida, Yuc. (Mexico)

    2009-09-15

    The corrosion resistance of Al-Mg-Si/SiC{sub p} composites produced by the pressureless infiltration method [using SiC{sub p} preforms with 50% porosity containing rice hull ash (RHA) and four custom-made alloys with varying Si/Mg molar ratio] was evaluated in neutral 0.1 M NaCl solutions. The deleterious phase Al{sub 4}C{sub 3} was successfully suppressed in composites with Si/Mg molar ratios of 0.89 and 1.05, but not in those with lower Si/Mg molar ratios (0.12 and 0.49). Results of cyclic polarizations in deareated 0.1 M NaCl solutions showed that with increasing Si/Mg molar ratio, passive current density increased but pitting susceptibility decreased both for reinforced and unreinforced alloys. Immersion tests in aerated 0.1 M NaCl showed that for composites with Si/Mg molar ratios of 0.12 and 0.49 chemical degradation by hydrolysis of Al{sub 4}C{sub 3} was followed by intense anodic dissolution at the matrix-reinforcement interface, while composites corresponding to Si/Mg molar ratios of 0.89 and 1.05 did not exhibit intense localized attack. Possible reasons for the improvement in resistance to localized corrosion are discussed. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  10. MOLAR RATIOS OF C,N,P OF PARTICULATE MATTER AND THEIR VERTICAL FLUXES IN THE YELLOW SEA

    Institute of Scientific and Technical Information of China (English)

    王保栋; 战闰; 徐明德

    2002-01-01

    The vertical fluxes and molar ratios of carbon, nitrogen and phosphorus of suspended particulate matter in the Yellow Sea were studied based on the analysis of suspended particulate matter, sediments and sinking particles obtained by use of moored sediment traps. The POC:PON ratios indicate that most of the particulate organic matter in the Yellow Sea water column comes from marine life rather than the continent. The vertical fluxes of SPM, POC, PON and POP in the Yellow Sea are much higher than those in other seas over the world, and present a typical pattern in shallow epicontinental seas. The estimated residence time of the bioactive elements showed that the speed of the biogeochemical process of materials in the Yellow Sea is much shorter than that in the open ocean as there was high primary productivity in this region.

  11. 钙磷摩尔比对新型PCCP+DCPA体系骨水泥性能的影响%INFLUENCE OF CALCIUM TO PHOSPHATE MOLAR RATIO ON PERFORMANCE OF A NOVEL CALCIUM PHOSPHATE CEMENT

    Institute of Scientific and Technical Information of China (English)

    王秀鹏; 叶建东; 王迎军

    2007-01-01

    Partially crystallized calcium phosphates (PCCP) with different calcium to phosphate molar ratios (n(Ca)/n(P), the same below) and containing carbonate were synthesized by chemical precipitation method. A novel calcium phosphate cement was prepared by PCCP and dicalcium phosphate anhydrous (DCPA). The effects of n(Ca)/n(P) ratio on the properties of the PCCP-DCPA cement system were studied by X-ray diffraction, scanning electron microscope, porosity measurement, and compressive strength analysis.The results show that with the increase of n(Ca)/n(P) ratio, the compressive strength of the cement samples decreased significantly,whereas the crystallinity, porosity and pore fractions larger than 100 nm in the hydrated cement increased. The properties of the cement were greatly influenced by the n(Ca)/n(P) ratio. The n(Ca)/n(P) ratio must be carefully considered in the preparation of calcium phosphate cement.%用化学沉淀法合成了不同钙/磷摩尔比并含碳酸根的部分结晶磷酸钙(partially crystallized calcium phosphates,PCCP),用PCCP和无水磷酸氢钙(dicalcium phosphate anhydrous ,DCPA)配制了PCCP+DCPA体系磷酸钙骨水泥,用去离子水作为骨水泥的固化液.通过相组成的X射线衍射分析、扫描电子显微镜观察、孔隙率和抗压强度测定,研究了钙磷摩尔[n(Ca)/n(P)]对PCCP+DCPA磷酸钙骨水泥性能的影响.结果表明:随着部分结晶磷酸钙中n(Ca)/n(P)的提高,磷酸钙骨水泥试件的抗压强度明显下降,但磷酸钙骨水泥水化产物羟基磷灰石的结晶度提高,固化体中大于100 nm的孔隙增多、固化体的孔隙率增大,可见,n(Ca)/n(P)对磷酸钙骨水泥的性能有重要影响,在制备磷酸钙骨水泥时应选择适当的n(Ca)/n(P).

  12. Effect of the Si/Zr molar ratio on the synthesis of Zr-based mesoporous molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Apartado Postal 1-1010, Queretaro 76000 (Mexico)], E-mail: psalas@fata.unam.mx; Wang, J.A. [Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico); Armendariz, H.; Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Chen, L.F. [Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico)

    2009-03-15

    Highly ordered Zr-based mesoporous molecular sieves were synthesized via a surfactant-templated method and the effect of the Si/Zr molar ratio on the crystalline structure, textural properties and surface acidity were studied by XRD, FTIR, TEM and {sup 29}Si MAS-NMR techniques. FTIR spectra show that the intensity of the band around 890 cm{sup -1} which corresponds to the vibration of Si-O-Zr bond was increased with increasing of the zirconium content, therefore, this band may be used as an indicator of the degree of the zirconium incorporation into the Si-framework. When the zirconium content increased in the materials, the Q{sup 3}/Q{sup 4} value obtained from {sup 29}Si MAS-NMR was linearly increased, whereas, the intensity the XRD peaks was gradually reduced; as a result, the pore wall thickness of the resultant materials was gradually increased, the surface area and the structural regularity were diminished. In order to obtain Zr-MCM-41 with highly ordered mesostructure and large surface area, proper Si/Zr molar ratio is a key factor, e.g., Si/Zr should be no less than 10. It was also found that the Bronsted acid sites which resulted from charge unbalance or local structure deformation due to the Zr{sup 4+} incorporation into the vicinity of the hydroxyls carrying silicon were created on the surface of the Zr-MCM-41 solids; strong Bronsted acidity could be formed on the solid with high zirconium content.

  13. Molecular Dynamics Simulation Study of Skin Lipids: Effects of the Molar Ratio of Individual Components over a Wide Temperature Range.

    Science.gov (United States)

    Gupta, Rakesh; Rai, Beena

    2015-09-03

    Atomistic molecular dynamics (MD) simulations were employed to systematically investigate the effects of the molar ratio of the individual components cholesterol (CHOL), free fatty acid (FFA), and ceramides (CER) on the properties of the skin lipid bilayer over a wide temperature range (300-400 K). Several independent simulations were performed for bilayers comprised of only CER, CHOL, or FFA molecules as well as those made up of a mixture of CER:CHOL:FFA molecules in different molar ratios. It was found that CHOL increases the stability of the bilayer, since the mixed (CER:CHOL:FFA) 1:1:0, 1:1:1, and 2:2:1 bilayers remained stable until 400 K while the pure ceramide bilayer disintegrated around ∼390 K. It was also observed that CHOL reduces the volume spanned by ceramide molecules, thereby leading to a higher area per CER and FFA molecule in the mixed bilayer system. The CHOL molecule provided more rigidity to the mixed bilayer and led to a more ordered phase at elevated temperatures. The CHOL molecule provided fluidity to the bilayer below the phase transition temperature of CER and kept the bilayer rigid above the phase transition temperature. The FFA interdigitizes with CER molecules and increases the thickness of the bilayer, while rigid CHOL decreases the bilayer thickness. The presence of CHOL increases the compressibility of the bilayer which is responsible for the high barrier function of skin. The CER molecule forms inter- and intramolecular hydrogen bonds, while CHOL only forms intermolecular hydrogen bonds.

  14. Structural, Surface Morphology and Optical Properties of ZnS Films by Chemical Bath Deposition at Various Zn/S Molar Ratios

    Directory of Open Access Journals (Sweden)

    Fei-Peng Yu

    2014-01-01

    Full Text Available In this study, ZnS thin films were prepared on glass substrates by chemical bath deposition at various Zn/S molar ratios from 1/50 to 1/150. The effects of Zn/S molar ratio in precursor on the characteristics of ZnS films were demonstrated by X-ray diffraction, scanning electron microscopy, optical transmittance, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry. It was found that more voids were formed in the ZnS film prepared using the precursor with Zn/S molar ratio of 1/50, and the other ZnS films showed the denser structure as the molar ratio was decreased from 1/75 to 1/150. From the analyses of chemical bonding states, the ZnS phase was indeed formed in these films. Moreover, the ZnO and Zn(OH2 also appeared due to the water absorption on film surface during deposition. This would be helpful to the junction in cell device. With changing the Zn/S molar ratio from 1/75 to 1/150, the ZnS films demonstrate high transmittance of 75–88% in the visible region, indicating the films are potentially useful in photovoltaic applications.

  15. Effects of SrO/Al2O3 Molar Ratio on the Luminescent Characteristics of Rare—Earth Strontium Aluminate Phosphors

    Institute of Scientific and Technical Information of China (English)

    张玉军; 谭砂砾; 等

    2002-01-01

    The study on the effects of SrO/Al2O3molar ratio on the crystalline phases and photoluminescence characteistics of strontium aluminate phosphors co-activated with Eu2+andDy3+ were conductde by X-ray powder diffractometry ,fluorescence spectrometer and photometer.The strontium aluminate luminescent materials with different Sro/Al2O3molar ratio emit the visible lights with different color tone after removal of excitation.The peak wavelengths of the emission spectra drift in the direction of short wave,the quantity of Sr4A114O25crystalline phase molar ratio is near 1,the photoluminescence materials have high luminescent intensity,and when it is near0.75,they have long afterglow time.However,when SrO/Al2O3molar ratio is more than1,the luminescent materials appear strong alkaline in water solution;when SrO/Al2O3molar ratio is much less than 0.75,the samples need a higher temperature to be sintered.

  16. Preparation of anhydrous magnesium chloride in a gas-solid reaction with ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    Zhou Ningbo; Chen Baizhen; He Xinkuai; Li Yibing

    2006-01-01

    Dehydrated ammonium carnallite was synthesized with bischofite from salt lake and ammonium chloride solution in a 1:1 molar ratio of MgCl2:NH4Cl,dehydrated at 160℃ for about 4 h.The yield was above 85%.The product was then mixed with solid-state ammonium chloride with a 1:4 mass ratio for the further dehydration at 410℃.The decomposition of NH4Cl made a pressure of NH3 at 30.5 kPa to prevent the hydrolysis of ammonium carnallite.The anhydration of magnesium chloride was achieved at 700℃.The results showed that anhydrous magnesium chloride contains magnesium oxide in an amount that was less than 0.1% by weight.XRD pattern and SEM micrograph showed a good dispersion of ammonium carnallite and anhydrous magnesium chloride crystals with well-distributed big grains,just enough to meet the need for the production of magnesium metal in the electrolysis process.

  17. Matrix tablets: the effect of hydroxypropyl methylcellulose/anhydrous dibasic calcium phosphate ratio on the release rate of a water-soluble drug through the gastrointestinal tract I. In vitro tests.

    Science.gov (United States)

    Mamani, Pseidy L; Ruiz-Caro, Roberto; Veiga, María D

    2012-12-01

    Different hydroxypropyl methylcellulose (HPMC)/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed aiming to evaluate the influence of both components ratio in the control release of a water-soluble drug (theophylline). In order to characterise the matrix tablets, swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralised water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid). The HPMC/ADCP ratio has turned out to be the determinant in the matrix behaviour: the HPMC characteristic swelling behaviour was modulated, in some cases, by the ADCP characteristic acidic dissolution. When the HPMC/ADCP ratio was ≥0.69, buoyancy, continuous swelling and low theophylline dissolution rate from the matrices (H1, H2 and H3) were observed in all dissolution media. Consequently, these formulations could be adequate as gastro-retentive drug delivery systems. Additionally, HPMC/ADCP ratio ≤0.11 (H5 and H6) induces a pH-dependent drug release which could be applied to design control drug release enteric formulations (with a suitable enteric coating). Finally, a HPMC/ADCP ratio between 0.11 and 0.69 (H4) yield a gastrointestinal controlled drug release, due to its time-dependent buoyancy (7 h) and a total drug delivery in 17 h in simulated colonic fluid.

  18. Thin Films Derived by a Particulate Sol-Gel Route with Various Cr:Ti Molar Ratios

    Science.gov (United States)

    Mohammadi, M. R.; Fray, D. J.

    2014-11-01

    Nanocrystalline and nanostructured TiO2-Cr2O3 thin films and powders were prepared by a facile and straightforward aqueous particulate sol-gel route at low temperature of 400°C. The prepared sols showed a narrow particle size distribution with hydrodynamic diameter in the range of 17.7 nm to 19.0 nm. Moreover, the sols were stable over 4 months, with constant zeta potential measured during this period. The effect of the Cr:Ti molar ratio on the crystallization behavior of the products was studied. X-ray diffraction (XRD) analysis revealed that the powders crystallized at low temperature of 400°C, containing anatase-TiO2, rutile-TiO2, and Cr2O3 phases, depending on the annealing temperature and Cr:Ti molar ratio. Furthermore, it was found that Cr2O3 retarded the anatase to rutile transformation up to 800°C. The activation energy of crystallite growth was calculated to be in the range of 1.3 kJ/mol to 2.9 kJ/mol. Transmission electron microscopy (TEM) imaging showed that one of the smallest crystallite sizes was obtained for TiO2-Cr2O3 binary mixed oxide, being 5 nm at 500°C. Field-emission scanning electron microscopy (FESEM) analysis revealed that the deposited thin films had nanostructured morphology with average grain size in the range of 20 nm to 40 nm at 500°C. Thin films produced under optimized conditions showed excellent microstructural properties for gas sensing applications. They exhibited a remarkable response towards low concentrations of NO2 gas at low operating temperature of 200°C, resulting in increased thermal stability of sensing films as well as a decrease in their power consumption. Furthermore, calibration curves revealed that TiO2-Cr2O3 sensors followed the power law (where S is the sensor response, the coefficients A and B are constants, and [gas] is the gas concentration) for two types of gas, exhibiting excellent capability for detection of low gas concentrations.

  19. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

    Science.gov (United States)

    de la Lanza Espino, Guadalupe; Soto, Luis A

    2015-01-01

    The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC), nitrogen (TN), phosphorus (TP), elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm) displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1)). Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1)) than those closer to the channel axis (averaging 341-516 µmol g(-1); p <0.05). The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1)), whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1); p<0.05). The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4) indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16%) than those near the channel axis (50.0 to 66 µmol g(-1); 0.15 to 0.21%). C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP). We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

  20. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

    Directory of Open Access Journals (Sweden)

    Guadalupe de la Lanza Espino

    Full Text Available The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC, nitrogen (TN, phosphorus (TP, elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1. Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1 than those closer to the channel axis (averaging 341-516 µmol g(-1; p <0.05. The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1, whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1; p<0.05. The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4 indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16% than those near the channel axis (50.0 to 66 µmol g(-1; 0.15 to 0.21%. C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP. We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

  1. Effects of SrO/Al2O3 Molar Ratio on the Luminescent Characteristics of Rare-Earth Strontium Aluminate Phosphors

    Institute of Scientific and Technical Information of China (English)

    张玉军; 尹衍升; 谭砂砾

    2002-01-01

    The study on the effects of SrO/Al2O3 molar ratio on the crystalline phases and photoluminescence characteristics of strontium aluminate phosphors co-activ ated with Eu2+ and Dy3+ were conducted by X-ray powder diffractomet ry, fluorescence spectrometer and photometer. The strontium aluminate luminescen t materials with different SrO/Al2O3 molar ratio emit the visible lights wit h different color tone after removal of excitation. The peak wavelengths of the emission spectra drift in the direction of short wave, the quantity of Sr4Al 14O25 crystalline phase increases and the afterglow time lengthens wit h the SrO/Al2O3 reduction. The results show that when the SrO/Al2O3 mola r ratio is near 1, the photoluminescence materials have high luminescent intensi ty, and when it is near 0.75, they have long afterglow time. However, when SrO/ Al2O3 molar ratio is more than 1, the luminescent materials appear strong al k aline in water solution; when SrO/Al2O3 molar ratio is much less than 0.75, the samples need a higher temperature to be sintered.

  2. The effect of Cu/Zn molar ratio on CO2 hydrogenation over Cu/ZnO/ZrO2/Al2O3 catalyst

    Science.gov (United States)

    Shaharun, Salina; Shaharun, Maizatul S.; Mohamad, Dasmawati; Taha, Mohd F.

    2014-10-01

    Catalytic hydrogenation of carbon dioxide (CO2) to methanol is an attractive way to recycle and utilize CO2. A series of Cu / ZnO / Al2O3/ZrO2 catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N2 adsorption-desorption. Higher surface area, SABET values (42.6-59.9 m2/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m2/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  3. Effect of Molecular Weight and Molar Ratio of Dextran on Self-Assembly of Dextran Stearate Polymeric Micelles as Nanocarriers for Etoposide

    Directory of Open Access Journals (Sweden)

    Jaleh Varshosaz

    2012-01-01

    Full Text Available Amphiphilic polymer surfactants are composed of hydrophilic and hydrophobic polymers and are widely used in targeted drug delivery. The purpose of this study was the evaluation of the effect of molecular weight and molar ratio of dextran on physicochemical properties of dextran stearate polymeric micelles. Dextran stearate was synthesized by acylation of dextran with stearoyl chloride. Etoposide loaded polymeric micelles were prepared by dialysis method. The resulting micelles were evaluated for particle size, zeta potential, critical micelle concentration (CMC, drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of micelles were studied in CT-26 colorectal carcinoma cell line. Molecular weight and molar ratio of dextran-stearate were impressive on zeta potential, CMC, drug loading capacity, and release efficiency. Unlike polymer molecular weight, molar ratio of stearate had a significant effect on cytotoxicity and particle size of etoposide loaded micelles. Although molecular weight of dextran had no significant effect on cytotoxicity of micelles on CT-26 cells, it had drastic attributes for stability of polymeric micelles. Consequently, both variables of molecular weight of dextran and molar ratio of stearate should be taken into account to have a stable and effective micelle of dextran-stearate.

  4. Mercury and selenium in European catfish (Silurus glanis) from Northern Italian Rivers: can molar ratio be a predictive factor for mercury toxicity in a top predator?

    Science.gov (United States)

    Squadrone, S; Benedetto, A; Brizio, P; Prearo, M; Abete, M C

    2015-01-01

    The study of mercury and selenium bioaccumulation in fish is crucially important for evaluating the extent of contamination in freshwater environments, and the possible health risk posed for humans when the antagonistic interactions of these two elements are considered. Several factors affect the risk of mercury intake from fish consumption, including mercury levels, human consumption patterns, and sensitive populations (e.g., pregnant women, foetuses, young children and unknown genetic factors). The protective effects of selenium on mercury toxicity have been extensively publicised in recent years, particularly targeting fish consumers. In this study, mercury (Hg) and selenium (Se) concentrations were determined in the muscle of European catfish (Silurus glanis) collected from North Italian Rivers. Differences in mercury and selenium levels, as a function of size, gender and location were investigated. Hg was strongly related to length, gender and location, while Se levels are not dependent on fish size or location. The mean Se/Hg molar ratio was strongly affected by location, and significantly related to length and age. Selenium was in molar excess of mercury in all sites, with a rank order of mean Se/Hg molar ratio of the Parma River (2.55)>Po River (1.71)>Tanaro River (1.66)>Bormida River (1.36). However, in 37% of analyzed samples, Hg exceeded the maximum level set by 1881/2006/EC and 629/2008/EC in fish muscle. The molar ratio of Se/Hg was 0.5mg/kg), and therefore the mean molar ratio cannot be considered as a safety criterion in top predator fish.

  5. Circulating fluidized bed gasification of low rank coal: Influence of O2/C molar ratio on gasification performance and sulphur transformation

    Science.gov (United States)

    Zhang, Haixia; Zhang, Yukui; Zhu, Zhiping; Lu, Qinggang

    2016-08-01

    To promote the utilization efficiency of coal resources, and to assist with the control of sulphur during gasification and/or downstream processes, it is essential to gain basic knowledge of sulphur transformation associated with gasification performance. In this research we investigated the influence of O2/C molar ratio both on gasification performance and sulphur transformation of a low rank coal, and the sulphur transformation mechanism was also discussed. Experiments were performed in a circulating fluidized bed gasifier with O2/C molar ratio ranging from 0.39 to 0.78 mol/mol. The results showed that increasing the O2/C molar ratio from 0.39 to 0.78 mol/mol can increase carbon conversion from 57.65% to 91.92%, and increase sulphur release ratio from 29.66% to 63.11%. The increase of O2/C molar ratio favors the formation of H2S, and also favors the retained sulphur transforming to more stable forms. Due to the reducing conditions of coal gasification, H2S is the main form of the released sulphur, which could be formed by decomposition of pyrite and by secondary reactions. Bottom char shows lower sulphur content than fly ash, and mainly exist as sulphates. X-ray photoelectron spectroscopy (XPS) measurements also show that the intensity of pyrite declines and the intensity of sulphates increases for fly ash and bottom char, and the change is more obvious for bottom char. During CFB gasification process, bigger char particles circulate in the system and have longer residence time for further reaction, which favors the release of sulphur species and can enhance the retained sulphur transforming to more stable forms.

  6. The effect of different molar ratios of ZnO on characterization and photocatalytic activity of TiO2/ZnO nanocomposite

    Directory of Open Access Journals (Sweden)

    Shahram Moradi

    2016-07-01

    Full Text Available The TiO2/ZnO nanocomposite as a photocatalyst was prepared with different molar ratios of ZnO using the sol–gel method. The structures and properties were recognized with Fourier transform infra-red spectroscopy (FT-IR, scanning electron microscopy (SEM, and X-ray diffraction (XRD methods. The XRD study exhibited that the crystallization behavior of the nanocomposites was associated with the molar ratios of ZnO. The SEM images indicated that with increasing the molar ratio of TiO2/ZnO until 50:10, regular morphology can be seen. It should be of interest for catalytic purposes since it expectantly improves the surface area. Furthermore, the photocatalytic activity of the synthesized nanocomposites was investigated for decolorization of Methylene Blue (MB in water under UV irradiation in a batch reactor. The results revealed that the photocatalytic activity of nanocomposite with 50:10 M ratio of TiO2/ZnO was the best.

  7. Effect of reaction time and (Ca+Mg)/Al molar ratios on crystallinity of Ca-Mg-Al layered double Hydroxide

    Science.gov (United States)

    Heraldy, E.; Nugrahaningtyas, K. D.; Sanjaya, F. B.; Darojat, A. A.; Handayani, D. S.; Hidayat, Y.

    2016-02-01

    Ca-Mg-Al Layered Double Hydroxides (Ca-Mg-Al-LDH) compounds were successfully synthesized from brine water and AlCl3.6H2O as the starting materials by coprecipitation method. The product result was characterized by X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR). The effects of the reaction time and the molar ratios of the raw material on the crystallinity of Ca-Mg-Al-LDH were examining. Results show that increasing reaction time (30; 60 and 90 min.) could improve the crystallinity and monodispersity of layered double hydroxide compounds particles. The well-defined Ca-Mg- Al-LDH could be prepared with (Ca+Mg)/Al molar ratios 0.5.

  8. A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Alinat, Elodie, E-mail: elodie.alinat@chimie-paristech.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); Delaunay, Nathalie, E-mail: nathalie.delaunay@espci.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); Archer, Xavier, E-mail: xavier.archer@interieur.gouv.fr [Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris (France); Mallet, Jean-Maurice, E-mail: jean-maurice.mallet@es.fr [École Normale Supérieure-PSL Research University, Département de Chimie, 24 rue Lhomond, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); CNRS, UMR 7203 LBM, F-75005 Paris (France); Gareil, Pierre, E-mail: pierre.gareil@chimie-paristech.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France)

    2015-04-09

    Highlights: • New insights into the nitrocellulose alkaline denitration mechanism. • Linear correlation for molar ratio of nitrite-to-nitrate ions and nitrogen content. • Capillary electrophoresis monitoring of nitrite and nitrate ions. • Applications to explosive and non-explosive nitrocellulose-containing samples. • Improved performances (including safety) over classical methods. - Abstract: A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (n = 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1 h for alkaline hydrolysis, 3 min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1 M sodium hydroxide for 1 h at 60 °C)

  9. Theoretical insights into the effects of molar ratios on stabilities, mechanical properties, and detonation performance of CL-20/HMX cocrystal explosives by molecular dynamics simulation.

    Science.gov (United States)

    Hang, Gui-Yun; Yu, Wen-Li; Wang, Tao; Wang, Jin-Tao; Li, Zhen

    2017-01-01

    To research and estimate the effects of molar ratios on structures, stabilities, mechanical properties, and detonation properties of CL-20/HMX cocrystal explosive, the CL-20/HMX cocrystal explosive models with different molar ratios were established in Materials Studio (MS). The crystal parameters, structures, stabilities, mechanical properties, and some detonation parameters of different cocrystal explosives were obtained and compared. The molecular dynamics (MD) simulation results illustrate that the molar ratios of CL-20/HMX have a direct influence on the comprehensive performance of cocrystal explosive. The hardness and rigidity of the 1:1 cocrystal explosive was the poorest, while the plastic property and ductibility were the best, thus implying that the explosive has the best mechanical properties. Besides, it has the highest binding energy, so the stability and compatibility is the best. The cocrystal explosive has better detonation performance than HMX. In a word, the 1:1 cocrystal explosive is worth more attention and further research. This paper could offer some theoretical instructions and technological support, which could help in the design of the CL-20 cocrystal explosive.

  10. Nutritional status and phytate:zinc and phytate x calcium:zinc dietary molar ratios of lacto-ovo vegetarian Trappist monks: 10 years later.

    Science.gov (United States)

    Harland, B F; Smith, S A; Howard, M P; Ellis, R; Smith, J C

    1988-12-01

    A nutrition assessment of 16 members of a community of lacto-ovo vegetarian Trappist monks was conducted in 1977. Plasma zinc was found to be low-normal, which was attributed primarily to high intakes of phytate-containing foods. Individual and group counseling were instituted over a 10-year period in an attempt to emphasize the importance of wise food selection within the constraints of lacto-ovo vegetarianism. In 1987, a more comprehensive nutrition assessment of 21 members of the same community was performed. Food composites were analyzed, and 3-day instead of 24-hour dietary records were kept. Intakes of phytate-containing foods had decreased from 4,569 to 972 mg/day; intake of dietary zinc had increased from 7.4 to 9.7 mg/day; and the phytate:zinc molar ratio had decreased from 67 to 14 for the years 1977 and 1987, respectively. An analyzed phytate:zinc molar ratio of 9.8 and an analyzed phytate x calcium:zinc molar ratio of 0.3 were representative of the 1987 community. Both were within normal ranges. Plasma zinc had risen to upper-normal levels. The 1987 nutrition assessment showed that it is possible to be adequately nourished with a lacto-ovo vegetarian diet provided one has proper knowledge of the phytate-containing foods and the methods for compensating with foods of greater mineral density (primarily zinc).

  11. Influence of metal to ligand molar ratios on the supramolecular structure formation of Cu(II) with diaminopropane and iodide: Synthesis, structure, spectroscopic and DFT studies

    Science.gov (United States)

    Kharediya, Bhagwan; Shukla, Madhulata; Saha, Satyen; Sunkari, Sailaja

    2014-03-01

    Two new copper(II) complexes with 1,3-diaminopropane and iodide, viz., [{Cu ((1,3-diaminopropane)2 I (I3))}] (1) and [{Cu ((1,3 diaminopropane)2(I)2)}] (2) have been synthesized under self assembly conditions and structurally characterised to observe the structural variations brought about by varying ligand molar ratios, towards studying the effect of external factors on supramolecular structure formation, with a long term goal of obtaining magnetic materials. Corresponding to the variation in metal to ligand molar ratios from one to two, totally different products are obtained whose gross structural features are entirely different. The formation of 1, is unpredicted under given synthetic conditions and hence is interesting. The formation of 2, is as generally expected for the reacting components under given conditions. In case of 1, the metal ion's choice to adopt a square pyramidal geometry by coordinating to two ligand units and a coordinated iodide, even in the absence of sufficient moles of ligand, as in 2, is due to sub-molar ligand ratios complemented by weak hydrogen bonding interactions, operating between the ligand amino hydrogens and coordinated iodide and uncoordinated triiodide moiety. This approach of providing sub-molar amounts of ligand to the metal to satisfy its coordination requirements, appear to be a promising strategy towards obtaining novel solid systems of material relevance. Both the complexes are characterised structurally and spectroscopically. Further, both the structures were satisfactorily modelled by calculations based on Density Functional Theory (DFT), and their UV-visible spectra were analyzed in depth with the help of Time Dependent DFT (TD-DFT).

  12. Manganese-mitigation of cadmium toxicity to seedling growth of Phytolacca acinosa Roxb. is controlled by the manganese/cadmium molar ratio under hydroponic conditions.

    Science.gov (United States)

    Liu, Huimin; Zhang, Yuxiu; Chai, Tuanyao; Tan, Jinjuan; Wang, Jianwu; Feng, Shanshan; Liu, Geyu

    2013-12-01

    Manganese (Mn) can interact with cadmium (Cd) in environments and influence the toxic effect of Cd on plants. However, few studies have investigated the relationship between the Mn/Cd ratio and plant Cd-toxicity along Cd concentrations. In this paper, we studied the effects of external Mn/Cd molar ratios (0, 10, 30, 50 and 60) on Cd toxicity in the Mn hyperaccumulator and Cd tolerant plant, Phytolacca acinosa Roxb., at three Cd levels (50, 100 and 200 μM) under hydroponic conditions. Our result showed that seedling growth (y) under Cd stress was strongly positively related to the solution Mn/Cd molar ratio (SMCR). The relationship between the two variables under solution Cd concentrations was well explained by the linear regression model y=a+b1 (SMCR)+b2 (Solution-Cd). Increasing SMCR significantly reduced the Cd concentration and increased the Mn concentration in plant tissues. However, seedling growth was consistent with the shoot Mn/Cd molar ratio rather than with the Mn or Cd concentrations in plant tissues. At low levels of SMCR (e.g. 0 and 10), elevation of Mn distribution in shoot tissues might be a mechanism in P. acinosa seedlings to defend against Cd-toxicity. In comparison with low levels of SMCR, high levels of SMCR (e.g. 50 and 60) greatly alleviated lipid peroxidation and plant water-loss, and enhanced photosynthesis. However, the alleviated lipid peroxidation in the Mn-mitigation of Cd toxicity was likely to be the secondary effect resulting from the antagonism between Mn and Cd in the plant.

  13. Biodegradable in situ gelling delivery systems containing pilocarpine as new antiglaucoma formulations: effect of a mercaptoacetic acid/N-isopropylacrylamide molar ratio

    Directory of Open Access Journals (Sweden)

    Lai JY

    2013-10-01

    Full Text Available Jui-Yang Lai Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan Abstract: Ocular drug delivery is one of the most commonly used treatment modalities in the management of glaucoma. We have recently proposed the use of gelatin and poly(N-isopropylacrylamide (PNIPAAm graft copolymers as biodegradable in situ forming delivery systems for the intracameral administration of antiglaucoma medications. In this study, we further investigated the influence of carrier characteristics on drug delivery performance. The carboxyl-terminated PNIPAAm samples with different molecular weights were synthesized by varying the molar ratio of mercaptoacetic acid (MAA/N-isopropylacrylamide (NIPAAm from 0.05 to 1.25, and were determined by end-group titration. The preparation of gelatin-g-PNIPAAm (GN copolymers from these thermoresponsive polymers was achieved using carbodiimide chemistry. Our results showed that the carboxylic end-capped PNIPAAm of high molecular weight may lead to the lower thermal phase transition temperature and slower degradation rate of GN vehicles than its low molecular weight counterparts. With a decreasing MAA/NIPAAm molar ratio, the drug encapsulation efficiency of copolymers was increased due to fast temperature-triggered capture of pilocarpine nitrate. The degradation of the gelatin network could greatly affect the drug release profiles. All of the GN copolymeric carriers demonstrated good corneal endothelial cell and tissue compatibility. It is concluded that different types of GN-based delivery systems exhibit noticeably distinct intraocular pressure-lowering effect and miosis action, thereby reflecting the potential value of a MAA/NIPAAm molar ratio in the development of new antiglaucoma formulations. Keywords: gelatin, poly(N-isopropylacrylamide, glaucoma, chain transfer agent, ocular drug delivery

  14. Effects of the molar ratio on the photo-generated charge separation behaviors and photocatalytic activities of (BiO)2CO3-BiOBr composites

    Science.gov (United States)

    Chen, Jiufu; Zhong, Junbo; Li, Jianzhang; Huang, Shentian; Xiang, Zhen; Li, Minjiao

    2016-10-01

    The molar ratio of two semiconductors will remarkably influence the photo-induced charge separation behaviors of the composites constructed, thus affecting the corresponding photocatalytic activity. Therefore, it is critical to reveal the relationship between the molar ratio of two semiconductors and the photo-induced charge separation; the information can shed light on the study of nature of surface catalysis. In this work, (BiO)2CO3-BiOBr composites were facilely fabricated in-situ through a pore impregnating approach using HBr aqueous solution. The samples were studied by BET, XRD, SEM, UV-Vis DRS and surface photovoltage spectroscopy (SPS). The photocatalytic activities of the samples were evaluated by the discoloration of methyl orange (MO) aqueous solution upon the simulated sunlight illumination. The results reveal that the (BiO)2CO3-BiOBr composite with 3/4 M ratio of (BiO)2CO3/BiOBr displays the highest photo-induced charge separation rate and photocatalytic activity, the results further manifest that no different electronic transfer property occurs after coupling (BiO)2CO3 with BiOBr.

  15. Effect of Molar Ratio of Citric Acid to Metal Nitrate on the Structure and Catalytic Activity of NiO Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    WU Gang; TAN Xiao-yan; LI Gui-ying; HU Chang-wei

    2013-01-01

    NiO nanoparticles were prepared by means of sol-gel method via varying the ratio of citric acid to nickel nitrate.The samples were characterized by powder X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectroscopy,transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS).It was found that the molar ratio of citric acid to nickel nitrate has a great effect on the crystal structure and particle size of NiO.The increase of the molar ratio of citric acid to nickel nitrate is favorable to the formation of NiO smaller particles within the range tested.Compared to bulk NiO obtained by thermal decomposition,NiO nanoparticles possess more surface oxygen species O-.The activity test indicates that surface oxygen species O-plays a crucial role in the hydroxylation of benzene to phenol with hydrogen peroxide as oxidant.The active site may be originated from Ni2+ on the surface of the samples,while Ni0 does not contribute to the hydroxylation reaction.

  16. Molar ratios of therapeutic water-soluble phenothiazine⋅water-insoluble phospholipid adducts reveal a Fibonacci correlation and a putative link for structure–activity relationships

    DEFF Research Database (Denmark)

    Keyzer, Hendrik; Fey, S. J.; Thornton, Barry

    2015-01-01

    1,2diacyl-sn-glycero-3-phospholipids (PL) with even-numbered symmetric saturated diacyl chains with the headgroups choline (PC), glycerol (PG), serine (PS), ethanolamine (PE), phosphatidic acid (PA). We observed water soluble products with replicable molar ratios (MR) that could be divided into two...... larger than that of the self-associated pure PTH. In summary, the reproducibility and similarity of the measurements using different PTH derivatives and PL suggests that similar adducts are formed in all the cases. We propose that the PTH$PL adduct has a “helical shape” showing Fibonacci properties...

  17. The Influence of Molar Ratio of Methanol to PFAD and Esterification Reaction Time towards Biodiesel Characteristics Palm Fatty Acids Distillate Produced

    Directory of Open Access Journals (Sweden)

    Ira Desri Rahmi

    2013-01-01

    Full Text Available PFAD is potential enough to be developed as a biodiesel feedstock because it is cheap and always available. But the FFA in PFAD is so high, so esterification process is necessary to lower levels of the FFA. High levels of FFA PFAD and a solid form at room temperature need necessary studies to determine the needs of methanol as a reactant and reaction time esterification for high yield and characteristics of biodiesel. Esterification of PFAD were carried out to study the effect of : molar ratios of methanol to PFAD of 6 : 1 – 10 : 1 and reaction time  of 60 – 120 min. The optimum condition for esterification process was molar ratio of methanol to PFAD at 10 : 1 with 2 wt% of H2SO4 at 60˚C and 60 min. The amount of FFA was reduced from 97,17 wt% to less then 10 wt %,  at the end of esterification process. The characteristic of biodiesel produced were 9.36 mg KOH/gr acid value, 5.01% FFA, 244 mg KOH/g saponification, 47.94 mg I/gr iodine value, 890 kg/m3 density,  and negative result for determination water and sediment content.

  18. Nitrite to nitrate molar ratio is inversely proportional to oxidative cell damages and granulocytic apoptosis at the wound site following cutaneous injury in rats.

    Science.gov (United States)

    Zunić, Gordana; Colić, Miodrag; Vuceljić, Marina

    2009-06-01

    Nitric oxide (NO) metabolism in response to the inflammatory cell infiltration and their apoptosis at the wound site, using a model of subcutaneously implanted sponges in Albino Oxford rats, were examined. The injured animals were sacrificed at days 1, 2 and 3 after the injury. Nitrites, nitrates (final products of NO metabolism), malondialdehyde (an indicator of oxidative cell damages), urea (product of arginase activity) and other parameters were measured both in plasma and wound fluid samples. Nitrite to nitrate molar ratio and sum of nitrites and nitrates (NO(x)) were calculated. The total cell numbers were at similar level throughout the examined period, but a gradual decrease of viable granulocytes, mainly due to the increased apoptosis, and the increase of monocyte-macrophage number occurred after the second day. A gradual increase of wound fluid nitrates, NO(x) and malondialdehyde suggested the increases of both NO and free oxygen radicals production. Interestingly, wound fluid nitrites peaked at the first day decreasing to the corresponding plasma levels thereafter. Wound fluid nitrite to nitrate molar ratio gradually decreased and negatively correlated both with the number of apoptotic cells (r= -0.752, poxidative cell damages and cell apoptosis at the wound site early after the cutaneous wound. Moreover, the obtained findings suggest that measurement of both nitrites and nitrates contribute to better insight into overall wound NO metabolism.

  19. Molar Pregnancy

    Science.gov (United States)

    ... may check for other medical problems, including: Preeclampsia Hyperthyroidism Anemia A molar pregnancy can't continue as a normal viable pregnancy. To prevent complications, the molar tissue must be removed. Treatment usually consists of one or more of the ...

  20. Effect of NH4-N/P and Ca/P molar ratios on the reactive crystallization of calcium phosphates for phosphorus recovery from wastewater

    Science.gov (United States)

    Vasenko, Liubov; Qu, Haiyan

    2017-02-01

    In this work, the effects of operational parameters, initial phosphorus concentration and molar ratios of Ca/P and NH4-N/P (further in the text N/P), on the nature and purity of precipitated phosphorus products have been investigated in an artificial system that mimics the supernatant in wastewater treatment plants. Metastable zone width was determined for two target phosphorus products: DCPD (dicalcium phosphate dihydrate) and HAp (hydroxyapatite) in the range of pH 4.5 - 7. HAp crystallizes at final pH higher than 6.3 while DCPD crystallizes at the final pH in between 4.7 and 5.7. At the final pH 5.7 - 6.3 and at pH lower than 4.7 the mixtures of DCPD and HAp were obtained. It was observed that N/P ratio affects not only the metastable zone width but also the kinetics of crystal growth for both DCPD and HAp: the higher the N/P ratio, the lower is the growth rate for both P-products. Investigation of the effect of Ca/P and N/P ratios on the nucleation and crystal growth of DCPD in batch crystallization experiment was performed. It showed that at high supersaturation level, crystals with larger median size can be obtained at higher N/P ratio despite the negative effects of N/P ratio on the growth rate of the crystals.

  1. MOLAR UPRIGHTING

    Directory of Open Access Journals (Sweden)

    Eka Erwansyah

    2006-04-01

    Full Text Available The mesial tipping of molar is frequently found in orthodontic cases. This molar malposition must be corrected since it may cause periodontal disorders, occlusal interferences, and temporomandibular joint dysfunction, and is often needed in planning a fixed bridge. This paper is a literature study to discuss about appliance designs, indication, and contraindications, and complication and treatment protocols of molar uprighting by fixed orthodontic appliances. By knowing the techniques of molar uprighting, the moments mentioned above can be avoided.

  2. Structural and magnetic properties of Co{sub x}Fe{sub 3−x}O{sub 4} versus Co/Fe molar ratio

    Energy Technology Data Exchange (ETDEWEB)

    Dippong, Thomas, E-mail: dippong.thomas@yahoo.ro [Technical University of Cluj-Napoca, North University Center of Baia Mare, Department of Chemistry and Biology, 76 Victoriei Street, 430122 Baia Mare (Romania); Levei, Erika Andrea, E-mail: erika.levei@icia.ro [INCDO-INOE 2000, Research Institute for Analytical Instrumentation, 67 Donath Street, 400293 Cluj-Napoca (Romania); Diamandescu, Lucian [National Institute of Materials Physics, 105bis Atomistilor Street, 077125 Magurele (Romania); Bibicu, Ion, E-mail: bibicu@infim.ro [National Institute of Materials Physics, 105bis Atomistilor Street, 077125 Magurele (Romania); Leostean, Cristian [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293 Cluj-Napoca (Romania); Borodi, Gheorghe, E-mail: borodi@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293 Cluj-Napoca (Romania); Barbu Tudoran, Lucian, E-mail: lbarbu@hasdeu.ubbcluj.ro [Babes-Bolyai University, Faculty of Biology and Geology, 44 Bilascu Street, 400015 Cluj-Napoca (Romania)

    2015-11-15

    Co{sub x}Fe{sub 3−x}O{sub 4} (x=0.5–2.5) magnetic nanoparticles were synthesized via redox reaction between cobalt nitrate, iron nitrate and 1-4-butanediol using five Co/Fe molar ratios, followed by calcination at 1000 °C. Single phase nanoscaled cobalt ferrite was obtained at x=1.0 and at slight Co excess (x=1.5), while at high Co/Fe molar ratios (x=2.0 and x=2.5) the prevailing phase was CoO accompanied by CoFe{sub 2}O{sub 4} traces. The highest values of coercive field and saturation magnetization were obtained for the sample at x=1.0, while the lowest values were obtained in the sample with the highest Co excess (x=2.5). The results indicated that the used synthesis route was suitable for the synthesis of cobalt ferrite with moderate saturation magnetization and high coercive field values. - Highlights: • Cobalt ferrite magnetic nanoparticles were synthesized by redox reaction. • The magnetic properties of Co{sub x}Fe{sub 3−x}O{sub 4} depend on the Co/Fe ratio. • Nanoparticles were spherical with sizes in the range of 30–73 nm. • At Co/Fe stoichiometric ratio and slight Co excess single phase CoFe{sub 2}O{sub 4} results. • The critical role of Co concentration in the synthesized samples was revealed.

  3. Novel Microwave-Assisted Synthesis of Poly(D,L-lactide: The Influence of Monomer/Initiator Molar Ratio on the Product Properties

    Directory of Open Access Journals (Sweden)

    Ljubisa Nikolic

    2010-05-01

    Full Text Available Poly(D,L-lactide synthesis using tin(II 2-ethylhexanoate initiated ring-opening polymerization (ROP takes over 30 hours in bulk at 120 °C. The use of microwave makes the same bulk polymerization process with the same initiator much faster and energy saving, with a reaction time of about 30 minutes at 100 °C. Here, the poly(lactide synthesis was done in a microwave reactor, using frequency of 2.45 GHz and maximal power of 150 W. The reaction temperature was controlled via infra-red system for in-bulk-measuring, and was maintained at 100 °C. Different molar ratios of monomer and initiator, [M]/[I], of 1,000, 5,000 and 10,000 were used. The achieved average molar masses for the obtained polymers (determined by gel permeation chromatography were in the interval from 26,700 to 112,500 g/mol. The polydispersion index was from 2.436 to 3.425. For applicative purposes, the obtained material was purified during the procedure of microsphere preparation. Microspheres were obtained by spraying a fine fog of polymer (D,L-lactide solution in tetrahydrofuran into the water solution of poly(vinyl alcohol with intensive stirring.

  4. Formation of copper nanoparticles in mordenite s with variable SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios under redox treatments

    Energy Technology Data Exchange (ETDEWEB)

    Petranovskii, V.; Avalos, M. [UNAM, Centro de Nanociencias y Nanotecnologia, Km 107 Carretera Tijuana-Ensenada, 22800 Ensenada, Baja California (Mexico); Stoyanov, E. [University of California, Department of Chemistry, Riverside, 92521 California (United States); Gurin, V. [Belarusian State University, Research Institute for Physical Chemical Problems, Minsk 220080 (Belarus); Katada, N. [Tottori University, Department of Chemistry and Biotechnology, Tottori 680-8552 (Japan); Hernandez, M. A. [Benemerita Universidad Autonoma de Puebla, Departamento de Investigacion en Zeolitas, Ciudad Universitaria, Puebla (Mexico); Pestryakov, A. [Tomsk Polytechnic University, Tomsk 634050 (Russian Federation); Chavez R, F.; Zamorano U, R. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, Zacatenco, 07738 Mexico D. F. (Mexico); Portillo, R., E-mail: vitalii@cnyn.unam.mx [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Ciudad Universitaria, Puebla (Mexico)

    2013-05-01

    A series of protonated copper-containing mordenite s with different SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios (MR) in the range of 10{<=}MR{<=}206 was prepared by ion exchange in copper nitrate aqueous solution. The electron paramagnetic resonance of hydrated copper Mordenite s series testifies of several Cu{sup 2+} ion sites. Hydrogen reduction of copper ions incorporated into the mordenite s was shown to lead to different reduced copper species including small metallic particles inter alia. The structural properties and acidity of mordenite s were characterized. The optical appearance of the copper particles showed strong but nonmonotonic dependence on the MR value, in line with the variation in acidity of this series of mordenite s. Correlations between mordenite properties and the formation of different reduced copper species are discussed. (Author)

  5. Modelling Chemical Kinetics of Soybean Oil Transesterification Process for Biodiesel Production: An Analysis of Molar Ratio between Alcohol and Soybean Oil Temperature Changes on the Process Conversion Rate

    Directory of Open Access Journals (Sweden)

    Maicon Tait

    2006-12-01

    Full Text Available A mathematical model describing chemical kinetics of transesterification of soybean oil for biodiesel production has been developed. The model is based on the reverse mechanism of transesterification reactions and describes dynamics concentration changes of triglycerides, diglycerides, monoglycerides, biodiesel, and glycerol production. Reaction rate constants were written in the Arrhenius form. An analysis of key process variables such as temperature and molar ratio soybean oil- alcohol using response surface analysis was performed to achieve the maximum soybean conversion rate to biodiesel. The predictive power of the developed model was checked for the very wide range of operational conditions and parameters values by fitting different experimental results for homogeneous catalytic and non-catalytic processes published in the literature. A very good correlation between model simulations and experimental data was observed.

  6. Phosphorus release from anaerobic peat soil during convective discharge – effect of soil Fe:P molar ratio and preferential flow

    DEFF Research Database (Denmark)

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    2014-01-01

    was controlled by reductive Fe(III) dissolution, and was well predicted from the soil FeBD:PBD molar ratio. Continuous convective column discharge with oxygen-free deionised water at 1 mm h− 1 for 10 effluent pore volumes resulted in highly variable in situ redox potential (Eh from − 200 to 300 mV), effluent Fe...... influence of soil geochemistry and local scale active flow volume. Combining batch incubation experiments and continuous column discharge experiments, we investigated iron (Fe) reduction and P release from 10 anoxic Fe-dominated (oxalate extractable Fe (Feox) from ~ 5500 to 50,000 mg kg− 1) lowland peat......(II) concentrations (23 to 2000 μM) and effluent dissolved reactive phosphorus (DRP) concentrations (discharge (3...

  7. Glycerol capped PbS/CdS core/shell nanoparticles at different molar ratio and its application in biosensors: An optical properties study

    Science.gov (United States)

    Das, D.; Hussain, A. M. P.

    2016-05-01

    Glycerol capped PbS/CdS core/shell type nanoparticles fabricated with two different molar ratios are characterized for study of structural and optical properties. The X-ray diffraction (XRD) pattern exhibits cubic phased polycrystalline nanocrystals. The calculated grain sizes from Williamson-Hall plot were found to be around 6 nm with increased strain. HRTEM investigation confirms the formation of core/shell nanostructures and the sizes of the particles were found to be around 7 nm which is in good agreement with the results of the W-H plot. An increase of band gap with the decrease in precursor concentration is confirmed from the blue shift in the absorption spectra and also from Tauc plot. A clear blue shifted intense emission is observed in the photoluminescence spectra with decrease in particle size. Intense luminescence from the core/shell nanostructure may be applied in bio labelling and biosensors.

  8. Deciduous molar hypomineralization and molar incisor hypomineralization.

    Science.gov (United States)

    Elfrink, M E C; ten Cate, J M; Jaddoe, V W V; Hofman, A; Moll, H A; Veerkamp, J S J

    2012-06-01

    This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop during a period similar to that of second primary molars, with possible comparable risk factors for hypomineralization. Children with DMH have a greater risk of developing MIH. Clinical photographs of clean, moist teeth were taken with an intra-oral camera in 6,161 children (49.8% girls; mean age 74.3 mos, SD ± 5.8). First permanent molars and second primary molars were scored with respect to DMH or MIH. The prevalence of DMH and MIH was 9.0% and 8.7% at child level, and 4.0% and 5.4% at tooth level. The Odds Ratio for MIH based on DMH was 4.4 (95% CI, 3.1-6.4). The relationship between the occurrence of DMH and MIH suggests a shared cause and indicates that, clinically, DMH can be used as a predictor for MIH.

  9. Synthesis of geopolymer from spent FCC: Effect of SiO2/Al2O<3 and Na2O/SiO2 molar ratios

    Directory of Open Access Journals (Sweden)

    Trochez, J. J.

    2015-03-01

    Full Text Available This paper assesses the feasibility of using a spent fluid catalytic cracking catalyst (SFCC as precursor for the production of geopolymers. The mechanical and structural characterization of alkali-activated SFCC binders formulated with different overall (activator + solid precursor SiO2/Al2O3 and Na2O/SiO2 molar ratios are reported. Formation of an aluminosilicate ‘geopolymer’ gel is observed under all conditions of activation used, along with formation of zeolites. Increased SiO2/Al2O3 induces the formation of geopolymers with reduced mechanical strength, for all the Na2O/SiO2 ratios assessed, which is associated with excess silicate species supplied by the activator. This is least significant at increased alkalinity conditions (higher Na2O/SiO2 ratios, as larger extents of reaction of the spent catalyst are achieved. SiO2/Al2O3 and Na2O/SiO2 ratios of 2.4 and 0.25, respectively, promote the highest compressive strength (67 MPa. This study elucidates the great potential of using SFCC as precursor to produce sustainable ceramic-like materials via alkali-activation.Este artículo estudia la factibilidad de usar un catalizador gastado del proceso de craqueo (SFCC para la producción de geopolímeros. Se evalúan las características mecánicas y estructurales de los geopolímeros producidos con diferentes relaciones molares (activador + precursor solido de SiO2/Al2O3 y Na2O/SiO2. La formación de un gel geopolimérico de tipo aluminosilicato se observa a las diferentes condiciones evaluadas, así como la formación de zeolitas. Un incremento en la relación SiO2/Al2O3 genera geopolímeros de baja resistencia mecánica, a las diferentes relaciones molares Na2O/SiO2 evaluadas, como consecuencia del exceso de especies silicato provenientes del activador. Este efecto es menos significativo al incrementar las condiciones de alcalinidad (mayores relaciones Na2O/SiO2, ya que un mayor grado de reacción del catalizador gastado es alcanzado. Las

  10. Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes

    Science.gov (United States)

    Alnoor, Hatim; Pozina, Galia; Khranovskyy, Volodymyr; Liu, Xianjie; Iandolo, Donata; Willander, Magnus; Nur, Omer

    2016-04-01

    Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5 M exhibit stronger yellow emission (˜575 nm) compared to those based on 1:1 and 1:3 M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination.

  11. The effect of balanced fertilization on nutrients’ concentration and phytic acid to zinc molar ratio in Iranian red been (Phaseolus calcaratus L. cultivars at different stages of seed development

    Directory of Open Access Journals (Sweden)

    B. Motesharezadeh

    2012-06-01

    Full Text Available Phytic acid is the main source of organic phosphorus in grains of legumes and cereals. It has great ability of bonding with metals and minerals such as iron, zinc and calcium. As a result, the solubility of these elements and their absorption capability by human will be reduced. This greenhouse research was carried out with the aim of studying the variations of phytic acid to zinc molar ratio and evaluation of nutrients’ concentration in different varieties of red bean (Phaseolus calcaratus L. under balanced fertilization conditions (based on soil test in different timings after flowering stage. Treatments included: 5 varieties of red bean (Akhtar, Naz, Derakhshan, Goli and Sayyad, two levels of fertilizer (control and balanced fertilization and 3 times of sampling (12, 22 and 32 days after flowering; T1, T2 and T3, respectively in a factorial arrangement with complete randomized blocks design. Phosphorous, potassium, iron and zinc concentration and phytic acid to zinc molar ratio in grains of different red bean cultivars were determined. The results of analysis of variance showed that the effect of cultivar, fertilizer and sampling time on concentration of zinc, iron, potassium, phosphorous and phytic acid to zinc molar ratio in grain was significant (P<0.01. Also, the highest concentration of zinc in grain was measured in Goli cultivar at T3 timing. The phytic acid to zinc molar ratio in balanced-fertilization treatment was recorded for Goli cultivar at T1, T2 and T3 timings as 11.1, 10.49 and 7.99, respectively. In general, the results of this research showed that balanced fertilization reduced phytic acid to zinc molar ratio. This can be effective in enhancing humans’ health by improving the absorption capability of required nutrients. More investigations under field conditions are recommended.

  12. The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shaharun, Salina, E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Taha, Mohd F., E-mail: faisalt@petronas.com.my [Department of Fundamental and Applied Science, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Mohamad, Dasmawati, E-mail: dasmawati@kck.usm.my [School of Dental Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2014-10-24

    Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.6–59.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  13. 7 CFR 58.325 - Anhydrous milkfat.

    Science.gov (United States)

    2010-01-01

    ... eligible for official certification, the anhydrous milkfat shall be made by a continuous separation process directly from milk or cream. The cream used shall be comparable to the flavor quality specified above for...

  14. 21 CFR 573.180 - Anhydrous ammonia.

    Science.gov (United States)

    2010-04-01

    ... silage. (2)(i) The food additive anhydrous ammonia is applied directly to corn plant material for use in... to corn plant material containing 28 to 38 percent dry matter. (iv) The silage treated with...

  15. Anhydrous Taphole Mix for Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan

    2010-01-01

    @@ 1 Scope This standard specifies the term,definition,brand,label,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of anhydrous taphole mix for blast furnace.

  16. Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4 Nanocrystal as Calcined Products of Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Abdullah Ahmed Ali Ahmed

    2014-01-01

    Full Text Available The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH nanostructure at different Zn2+/Fe3+ molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD. LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4. The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4 and 43.3 nm for ZnO. The photocatalytic activity of the calcination products was investigated using ultraviolet-visible-near infrared (UV-VIS-NIR diffuse reflectance spectroscopy. The magnetic properties of calcined LDHs were investigated using a vibrating sample magnetometer (VSM. The calcined samples showed a paramagnetic behavior for all Zn2+/Fe3+ molar ratios. The effect of molar ratio on magnetic susceptibility of the calcined samples was also studied.

  17. Influência do agente de cloração do catalisador à base de veodímio e da razão molar Cl: Nd na polimerização do butadieno Influence of the chlorinating agent of neodymium based catalysts and Cl: Nd molar ratio on butadiene polymerization

    Directory of Open Access Journals (Sweden)

    Cintia N. Ferreira

    2009-06-01

    Full Text Available Neste trabalho foi utilizado um sistema catalítico composto por hidreto de diisobutilalumínio (DIBAH, versatato de neodímio (NdV e um agente de cloração para avaliar a influência da fonte de cloro e da razão molar Cl:Nd nas características da reação de polimerização (conversão e constante de velocidade de propagação e do polibutadieno (massa molecular e microestrutura. Os agentes de cloração estudados foram cloreto de t-butila (t-BuCl, sesquicloreto de etilalumínio (EASC e cloreto de dietilalumínio (DEAC. As razões molares Cl:Nd utilizadas foram: 1:1, 3:1 e 5:1 para o t-BuCl; 0,5:1, 1:1 e 3:1 para o EASC e 1:1, 1,5:1, 3:1 e 5:1 para o DEAC. Foi observada a existência, para cada agente de cloração, de um valor ótimo de razão molar Cl:Nd para o qual a conversão foi máxima. O DEAC apresentou uma maior conversão em relação aos outros agentes de cloração; em contrapartida, o t-BuCl produziu polibutadienos com maior teor de unidades 1,4-cis e maior massa molecular (n e wIn this work catalyst systems consisting of diisobutylaluminium hydride (DIBAH, neodymium versatate (NdV and a chlorinating agent were employed to study the influence of the chloride source and Cl:Nd molar ratio on 1,3-butadiene polymerization and polybutadiene's characteristics (molecular weight and microstructure. The chloride sources studied were t-butyl chloride, ethylaluminium sesquichloride (EASC and diethylaluminium chloride (DEAC. The Cl:Nd molar ratios used were 1:1, 3:1 e 5:1 for t-butyl chloride; 0.5:1, 1:1 and 3:1 for EASC and 1:1, 1.5:1, 3:1 and 5:1 for DEAC. A maximum value of Cl:Nd molar ratio exists. Moreover, DEAC showed to be more reactive than EASC and t-BuCl but t-BuCl produced higher molecular weight and cis-1,4 units contents.

  18. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2015-05-01

    Full Text Available This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA using LUSI (Sidoarjo mud and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  19. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer.

    Science.gov (United States)

    Razak, Rafiza Abdul; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Hardjito, Djwantoro; Yahya, Zarina

    2015-05-21

    This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  20. Inflammation and wound healing in cats with chronic gingivitis/stomatitis after extraction of all premolars and molars were not affected by feeding of two diets with different omega-6/omega-3 polyunsaturated fatty acid ratios.

    Science.gov (United States)

    Corbee, R J; Booij-Vrieling, H E; van de Lest, C H A; Penning, L C; Tryfonidou, M A; Riemers, F M; Hazewinkel, H A W

    2012-08-01

    Feline chronic gingivitis/stomatitis (FCGS) is a painful inflammatory disease in cats. Extraction of teeth, including all premolars and molars, has been shown to be the therapy of choice in cats not responding sufficiently to home care (e.g. tooth brushing) and/or medical treatment (corticosteroids and/or antibiotics). In this study, we hypothesize that a cat food with an omega-6 polyunsaturated fatty acid (ω6 PUFA) to ω3 PUFA ratio of 10:1 reduces inflammation of the FCGS and accelerates soft tissue wound healing of the gingiva after dental extractions, compared to a cat food with a ω6:ω3 PUFA ratio of 40:1. The cats were fed diets with chicken fat and fish oil as sources of fatty acids. In one diet, part of the fish oil was replaced by safflower oil, resulting in two diets with ω6:ω3 PUFA ratios of 10:1 and 40:1. This double-blinded study in two groups of seven cats revealed that dietary fatty acids influence the composition of plasma cholesteryl esters and plasma levels of inflammatory cytokines. The diet with the 10:1 ratio lowered PGD(2) , PGE(2) and LTB(4) plasma levels significantly, compared to the diet with the 40:1 ratio (p = 0.05, p = 0.04, and p = 0.02 respectively). However, feeding diets with dietary ω6:ω3 PUFA ratios of 10:1 and 40:1, given to cats with FCGS for 4 weeks after extraction of all premolars and molars, did not alter the degree of inflammation or wound healing.

  1. Deciduous molar hypomineralization and molar incisor hypomineralization

    NARCIS (Netherlands)

    Elfrink, M.E.C.; ten Cate, J.M.; Jaddoe, V.W.V.; Hofman, A.; Moll, H.A.; Veerkamp, J.S.J.

    2012-01-01

    This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop dur

  2. Phase composition and catalytic performance of Mo/VPO catalysts with different P/V molar ratios%不同P与V比的Mo/VPO催化剂物相组成及其催化性能

    Institute of Scientific and Technical Information of China (English)

    曾炜; 顾龙勤; 徐俊峰; 陈亮

    2014-01-01

    A series of Mo doped VOHPO4·0.5H2O precursors with different P/ V molar ratios was prepared by organic method. Mo / VPO catalysts were obtained by calcining the precursors and then activating in the mixed gas atmosphere 50% air-40% N2-10% steam( volume fraction). The catalytic performance of the catalysts for the oxidation of n-butane to maleic anhydride was investigated in a fixed bed reactor. The results showed that the activity of Mo / VPO catalyst was weakened with the increase of P/ V molar ratios, and the selectivity to maleic anhydride had no linear relationship with P/ V molar ratios. Mo / VPO catalyst with P/ V molar ratio 0. 9 exhibited the best catalytic performance. The results of XRD characterization indicated that the main active phases of Mo / VPO catalyst for the oxidation of n-butane to maleic anhydride were(VO)2 P2 O7 and V/ P mica phases,the formation of which were depended on the calcina-tion conditions. A small amount of V2 O5 in Mo/ VPO catalyst with low P/ V molar ratio was benefitial to the enhancement of catalyst activity and the selectivity to maleic anhydride. Excess V2 O5 ,however,lowered the selectivity to maleic anhydride because of deep oxidation. V/ P mica phase existed in the catalyst had a great effect on shortening activation time and improving the selectivity to maleic anhydride according to the activation tests.%采用有机相法制备了不同 P 与 V 物质的量比的 Mo 掺杂 VOHPO4·0.5H2 O 前驱体,并通过体积分数为50%空气-40%氮气-10%水蒸汽混合气氛活化得到 Mo / VPO 催化剂,采用固定床反应器评价其催化正丁烷氧化制顺酐的性能。结果表明,Mo / VPO 催化剂催化活性随 P 与 V 物质的量比的增大而降低,但顺酐选择性与 P 与 V 物质的量比并不呈线性关系,P 与 V 物质的量比为0.9的 Mo / VPO 催化剂具有最佳的催化性能。XRD 分析表明,Mo / VPO 催化剂催化正丁烷氧化制顺酐的主要活性物相为(VO)2 P

  3. NQR frequencies of anhydrous carbamazepine polymorphic phases

    CERN Document Server

    Bonin, C J; Pusiol, D J

    2010-01-01

    In this work we propose the Nuclear Quadrupole Resonance (NQR) technique as an analytical method suitable for polymorphism detection in active parts (or active principles) of pharmaceuticals with high pharmacological risk. Samples of powder carbamazepine (5H-dibenz(b,f)-azepine-5-carboxamide) are studied. In its anhydrous state, this compound presents at least three different polymorphic forms: form III, the commercial one, form II, and form I. Of these, only form III possesses desirable therapeutic effects. By using the NQR technique, it was possible to characterize two of the three polymorphic phases (I and III) for anhydrous carbamazepine in few minutes at room temperature, detecting the characteristic frequencies of 14N nuclei (I=1) present in their chemical composition and in the frequency range 2.820-3.935 MHz. For form II, characteristic lines were not detected within this range of frequencies. The lines detected for form III are centered at the frequencies \

  4. The use of anhydrous ammonia for bioventing

    Energy Technology Data Exchange (ETDEWEB)

    Zytner, R.G.; Hallman, M.; Gimenez, B.F.; Jennings, R.; Leek, K. [Guelph Univ., ON (Canada). Faculty of Graduate Studies

    2002-07-01

    Soils contaminated with hydrocarbons can be effectively treated using bioventing remediation technology, an ideal method for removing residual contamination left by soil vapour extraction (SVE). Bioventing uses low or intermitted air flow rates to produce oxygen-rich conditions in the vadose zone, thereby promoting the formation of micro-organisms that can mineralize the hydrocarbons if enough nutrients are present. There is concern regarding the use of nutrients (the addition of nitrogen) to the subsurface because current applications methods cannot uniformly disperse nitrogen throughout the entire subsurface. Two research studies are being conducted using gasoline contaminated soil to address this concern. The first phase of the study focuses on how to best deliver nitrogen to the subsurface. Injecting anhydrous ammonia into the contaminated surface was one suggestion for stimulating the growth of hydrocarbon degraders. SVE extraction well models indicated this was an effective and safe way to disperse nitrogen. The second phase of the study involved the use of respirometers to compare total petroleum hydrocarbon (TPH) degradation with nitrogen additions in the form of NH{sub 4}Cl or anhydrous ammonia. The respirometers were run for about 1 month after which time it was determined that the use of anhydrous ammonia is an effective method to promote bioventing.

  5. Effect of Mg/B{sub 2}O{sub 3} molar ratio and furnace temperature on the phase evaluation and morphology of SiC–B{sub 4}C nanocomposite prepared by MASHS method

    Energy Technology Data Exchange (ETDEWEB)

    Roghani, Hamed [Semiconductor Department, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of); Tayebifard, Seyed Ali, E-mail: a_tayebifard@yahoo.com [Semiconductor Department, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of); Kazemzadeh, Asghar [Semiconductor Department, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of); Nikzad, Leila [Ceramic Department, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of)

    2015-07-01

    In this study, SiC–B{sub 4}C nanocomposite has been synthesized in situ successfully by Mechanical activated combustion synthesis method (MASHS). Initially Si, C, B{sub 2}O{sub 3} and Mg powders as raw materials were weighed according to different molar ratio of Mg to B{sub 2}O{sub 3}. In next step theses materials were milled in a planetary mill under Ar atmosphere. The synthesis step was performed in a tube furnace equipped with controlled atmosphere system. The different furnace temperature was investigated on the phase synthesis and morphology of the products. The specimens in the various steps were studied by XRD analysis for evaluation of the phase compositions and calculation of the average crystallite size of them. The morphology of synthesized products was investigated by scanning and transmission electron microscopes (SEM&TEM). The final product contains main phases MgO, B{sub 4}C and SiC. Also, In this sample byproducts were characterized such as Mg{sub 3}B{sub 2}O{sub 6}, Mg{sub 2}B{sub 2}O{sub 5} and remaining carbon. XRD pattern of synthesized sample showed the considerable effect of increasing Mg to B{sub 2}O{sub 3} molar ratio on reducing the amount of Mg{sub 3}B{sub 2}O{sub 6}, Mg{sub 2}B{sub 2}O{sub 5} and remaining carbon. SiC–B{sub 4}C composite was synthesized with more homogenous morphology by reducing the furnace temperature from 1000 to 900 °C, but reduction of temperature up to 800 °C give rise to uncompleted reaction whereas some unreacted Si remains. Average crystallite sizes of optimal sample were calculated 10.5 and 8 nm for SiC and B{sub 4}C respectively. These values are consisted of the TEM results somehow while grain size was less than 70 nm. Also SEM observation showed fine grains with sizes falling in the nanometer range. - Graphical abstract: Display Omitted - Highlights: • Composite prepared by combustion synthesis method in system of Si, C, B{sub 2}O{sub 3} and Mg. • More than stoichiometric Mg/B{sub 2}O{sub 3

  6. Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 calcined at different temperatures on its surface properties and glucose reactivity in near-critical methanol

    Institute of Scientific and Technical Information of China (English)

    Lincai Peng; Junping Zhuang; Lu Lin

    2012-01-01

    Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper.The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption,XRD,NH3-TPD and XPS techniques,respectively.It was found that the crystallization temperature of the samples increased after the combination of ZrO2 and TiO2; and phase transformations from the anatase to the rutile of TiO2 species and the tetragonal to the monoclinic of ZrO2 species were effectively suppressed at higher temperature.The sample with a Zr/Ti molar ratio of 3/1 calcined at 450 ℃ showed the highest surface area and the most acid sites among all the tested samples.The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature,however,decreased with the calcination temperature.The result indicates that the sulfur content in samples is a crucial factor to control the acid site density.Calcining the sample at 650 ℃ and higher temperatures resulted in a significant desorption of sulfate ion on the samples.The synthesized samples were evaluated as a potential catalyst for glucose conversion under the nearcritical methanol conditions (200 ℃/4 MPa).The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides,while the moderate acid sites were responsible for the formation of methyl levulinate.The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density.The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivity.

  7. Effect of different processes and Ti/Zn molar ratios on the structure, morphology, and enhanced photoelectrochemical and photocatalytic performance of Ti3+ self-doped titanium-zinc hybrid oxides

    Science.gov (United States)

    Fu, Rongrong; Wang, Qingyao; Gao, Shanmin; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Lu, Jun

    2015-07-01

    Ti3+ self-doped titanium-zinc hybrid oxides with different phase compositions and morphologies were successfully synthesized using Zn powder as the reductant and Zn source by a chemical-reduction precipitation method with subsequent thermal treatment. The fabricated Ti3+ self-doped TiO2(A)/TiO2(R), TiO2(A)/TiO2(R)/ZnTiO3, and TiO2(A)/ZnO heterojunctions were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The effects of various Ti/Zn molar ratios and preparation processes on the structural, morphological, optical, photocurrent and photocatalytic properties of the resultant samples were investigated systematically. Results reveal that Ti3+ self-doping enhances the photoabsorption capability of titanium-zinc hybrid oxides in the visible-light region. Moreover, different processes and Ti/Zn molar ratios play great influences on the structure, morphology, optical, photocurrent and photocatalytic properties of the final products. Ti3+ self-doped titanium-zinc hybrid oxides exhibit excellent photocurrent and photocatalytic activity than pure TiO2 and ZnTiO3 under visible-light irradiation (λ ≥ 400 nm). The most active Ti3+ self-doped titanium-zinc hybrid oxides photoanode presents significantly improved water splitting performance. The synergistic effect between the Ti3+ self-doped and heterojunctions is responsible for the enhanced performance of these materials.

  8. Effect of different processes and Ti/Zn molar ratios on the structure, morphology, and enhanced photoelectrochemical and photocatalytic performance of Ti3+ self-doped titanium–zinc hybrid oxides

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Rongrong; Wang, Qingyao; Gao, shanmin; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Lu, Jun

    2015-07-01

    Ti3+ self-doped titanium–zinc hybrid oxides with different phase compositions and morphologies were successfully synthesized using Zn powder as the reductant and Zn source by a chemical-reduction precipitation method with subsequent thermal treatment. The fabricated Ti3+ self-doped TiO2(A)/TiO2(R), TiO2(A)/TiO2(R)/ZnTiO3, and TiO2(A)/ZnO heterojunctions were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–Vis diffuse reflectance spectroscopy. The effects of various Ti/Zn molar ratios and preparation processes on the structural, morphological, optical, photocurrent and photocatalytic properties of the resultant samples were investigated systematically. Results reveal that Ti3+ self-doping enhances the photoabsorption capability of titanium–zinc hybrid oxides in the visible-light region. Moreover, different processes and Ti/Zn molar ratios play great influences on the structure, morphology, optical, photocurrent and photocatalytic properties of the final products. Ti3+ self-doped titanium–zinc hybrid oxides exhibit excellent photocurrent and photocatalytic activity than pure TiO2 and ZnTiO3 under visible-light irradiation (λ ≥ 400 nm). The most active Ti3+ self-doped titanium–zinc hybrid oxides photoanode presents significantly improved water splitting performance. The synergistic effect between the Ti3+ self-doped and heterojunctions is responsible for the enhanced performance of these materials.

  9. Theoretical insights into the stabilities, detonation performance, and electrostatic potentials of cocrystals containing α- or β-HMX and TATB, FOX-7, NTO, or DMF in various molar ratios.

    Science.gov (United States)

    Song, Ken-Peng; Ren, Fu-de; Zhang, Shu-Hai; Shi, Wen-Jing

    2016-10-01

    A molecular dynamics method was employed to study the binding energies associated with the cocrystallization (at selected crystal planes) of either 1,3,5-triamino-2,4,6-trinitro-benzene (TATB), 1,1-diamino-2,2-dinitroethylene, 3-nitro-1,2,4-triazol-5-one (TATB, FOX-7, and NTO, respectively, all of which are explosives), or N,N-dimethylformamide (DMF, a nonenergetic solvent) in various molar ratios with 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane in its α and β conformations (α-HMX and β-HMX, respectively). The results showed that the cocrystals with low molar ratios (2:1, 1:1, 1:2, and 1:3) were the most stable. The binding energies of HMX/NTO and HMX/DMF were larger than those of HMX/TATB and HMX/FOX-7. According to the calculated stabilities, HMX prefers to adopt its α form in HMX/TATB and its β form in HMX/NTO, whereas the two forms coexist in HMX/FOX-7. For HMX/TATB, HMX/NTO, and α-HMX/FOX-7, increasing the proportion of the cocrystal component with the highest detonation heat (HMX in the first two cases, FOX-7 in the latter) increases the detonation heat, velocity, and pressure of the cocrystal. However, increasing the proportion of the component with the highest detonation heat in β-HMX/FOX-7 and γ-CL-20/FOX-7 increases the detonation heat of the cocrystal but decreases its detonation velocity. An investigation of the surface electrostatic potential revealed how the sensitivity changes upon cocrystal formation. Graphical Abstract Surface electrostatic potential of HMX/TATB.

  10. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization.

    Science.gov (United States)

    Negre-Barber, A; Montiel-Company, J M; Boronat-Catalá, M; Catalá-Pizarro, M; Almerich-Silla, J M

    2016-08-25

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9-86.6) and the negative predictive value 84.7% (80.6-88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9-17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47-0.68). The odds ratio was 18.2 (9.39-35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH.

  11. An element with a liquid, anhydrous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Nankay, S.; Indzima, T.; Toyeguti, Y.

    1982-09-01

    A liquid anhydrous element and a heat treated Mn0/sub 2/ cathode, to which sodium silicate in the form of Na/sub 2/0 with 5/2Si0/sub 2/ liquid glass is added in a volume of 3 grams per 100 grams of Mn0/sub 2/ is used in the element with a light metal, lithium type anode. Moreover 4.5 grams of acetylene soot is added to the active cathode mass. A fluorine bearing resin is used as the binder. The cathode stores well.

  12. 46 CFR 98.25-5 - How anhydrous ammonia may be carried.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to...

  13. Effect of NO3-/NH4+ Molar Ratio on Hydroxyl Release From Wheat Roots%不同硝/铵比值对小麦幼苗根系释放氢氧根的影响

    Institute of Scientific and Technical Information of China (English)

    郭都; 徐仁扣

    2012-01-01

    为研发酸化土壤的生物修复技术,采用水培试验和自动电位滴定装置研究酸性条件下氮素形态对小麦幼苗根系释放氢氧根及培养液pH变化的影响.结果表明,小麦幼苗在初始pH值为4.0,n(NO3-):n(NH4+)比值(以下简称硝/铵比)分别为15∶1、3∶1和1∶1的营养液中培养6d后营养液pH升高,且增幅随硝/铵比的增加而增大,小麦对硝态氮的吸收量和氢氧根释放量呈相同的变化趋势,说明小麦对硝态氮的吸收偏好导致根系释放氢氧根,进而使得培养液pH升高.小麦幼苗在硝/铵比为3∶1,初始pH值分别为4.0、4.5和5.0的营养液中培养6d后,培养液pH和氢氧根释放量的增幅随初始pH的升高而降低,说明低pH条件有利于小麦幼苗对硝态氮的吸收,可促进小麦根系释放更多的氢氧根.10 h的恒定pH试验结果表明,恒定pH条件下小麦根系释放的氢氧根数量大于非恒定pH条件,且硝态氮比例越大,差值越大.因此,可以根据小麦在酸性条件下对硝态氮的吸收偏好建立酸化土壤的生物修复方法,即调节硝态氮含量以加大小麦根系的氢氧根释放量,进而提高土壤pH.%In order to develop methods for bioremediation of acid soils, hydroxyl release from roots of wheat seedlings in a hydroponic experiment as affected by form of nitrogen fertilizer under acidic conditions was investigated with an automatic titration system. Results show that pH of the nutrient solutions, 4. 0 in initial pH and 15 : 1, 3 : 1 and 1 : 1 in NO3-/NH4+ molar ratio separately, increased after 6 days of wheat culturing. The higher the molar ratio, the greater the increase in solution pH. Correspondingly, the absorption of nitrate by wheat and the release of hydroxyl from wheat roots also increased with the rising molar ratio. These findings suggest that the preferential absorption of nitrate by wheat and subsequent release of hydroxyl from wheat roots cause increase in solution pH. In

  14. Mercury and Selenium in Muscle and Target Organs of Scalloped Hammerhead Sharks Sphyrna lewini of the SE Gulf of California: Dietary Intake, Molar Ratios, Loads, and Human Health Risks.

    Science.gov (United States)

    Bergés-Tiznado, Magdalena E; Márquez-Farías, Fernando; Lara-Mendoza, Raúl E; Torres-Rojas, Yassir E; Galván-Magaña, Felipe; Bojórquez-Leyva, Humberto; Páez-Osuna, Federico

    2015-11-01

    Selenium and mercury were evaluated in muscle, liver, kidney, brain, and the stomach contents of juvenile scalloped hammerhead shark Sphyrna lewini. Se:Hg molar ratios were calculated. The average Hg levels in muscle ranged from 0.12 to 1.17 μg/g (wet weight); Hg was 1. Correlations were found for Hg in muscle with size, age, and weight, and also for Hg in liver with size, age, and weight. Hg in muscle was significantly positive correlated to Hg in brain as well as Hg in liver was correlated to Hg in kidney. The highest Hg in preys was for carangid fishes; scombrid and carangid fishes contributed with the highest Se levels. Results suggest that more than 98 % of the total Hg and 62 % of Se end up in muscle and might be affected by factors, such as geographical area, age, size, and feeding habits. The muscle of S. lewini should be consumed by people cautiously so as not to exceed the recommended intake per week.

  15. Third molar development: measurements versus scores as age predictor.

    Science.gov (United States)

    Thevissen, P W; Fieuws, S; Willems, G

    2011-10-01

    Human third molar development is widely used to predict chronological age of sub adult individuals with unknown or doubted age. For these predictions, classically, the radiologically observed third molar growth and maturation is registered using a staging and related scoring technique. Measures of lengths and widths of the developing wisdom tooth and its adjacent second molar can be considered as an alternative registration. The aim of this study was to verify relations between mandibular third molar developmental stages or measurements of mandibular second molar and third molars and age. Age related performance of stages and measurements were compared to assess if measurements added information to age predictions from third molar formation stage. The sample was 340 orthopantomograms (170 females, 170 males) of individuals homogenously distributed in age between 7 and 24 years. Mandibular lower right, third and second molars, were staged following Gleiser and Hunt, length and width measurements were registered, and various ratios of these measurements were calculated. Univariable regression models with age as response and third molar stage, measurements and ratios of second and third molars as predictors, were considered. Multivariable regression models assessed if measurements or ratios added information to age prediction from third molar stage. Coefficients of determination (R(2)) and root mean squared errors (RMSE) obtained from all regression models were compared. The univariable regression model using stages as predictor yielded most accurate age predictions (males: R(2) 0.85, RMSE between 0.85 and 1.22 year; females: R(2) 0.77, RMSE between 1.19 and 2.11 year) compared to all models including measurements and ratios. The multivariable regression models indicated that measurements and ratios added no clinical relevant information to the age prediction from third molar stage. Ratios and measurements of second and third molars are less accurate age predictors

  16. ["Molar-incisor hypomineralization"].

    Science.gov (United States)

    Kellerhoff, Nadja-Marina; Lussi, Adrian

    2004-01-01

    Hypocalcification of the enamel is the most common developmental disorder observed in teeth. The prevalence of this kind of hypomineralisation is about 10-19%. These molars are often referred to as cheese molars, because the lesions clinically resemble cheese in color and consistency. Other descriptions are: idiopathic enamel hypomineralisation in the permanent first molars, idiopathic enamel opacities in the permanent first molars, non fluoride enamel hypomineralisation in the permanent first molars, non-endemic mottling of enamel in the permanent first molars. Molar-Incisor Hypomineralisation is today the proposed expression for this disease. Occlusal surfaces of the first permanent molar are most commonly affected. The lesions are more frequent in the upper jaw than in the lower jaw. The incisors are affected to a lesser degree than the molars. Several aetiological factors can cause these defects. Some studies show a relation between intake of dioxins via mother's milk after prolonged breast feeding and developmental defects of the child's teeth. Because the ameloblasts are very sensitive to oxygen supply, complications involving oxygen shortages during birth or respiratory diseases such as asthma or bronchitis and pneumonia are discussed as further aetiological factors. Renal insufficiency, hypoparothyroidism, diarrhoea, malabsorption and malnutrition and high-fever diseases can be other reasons for the occurrence of these defects. Defective enamel can be a locus of lowered resistance for caries. Histologically there are areas of porosity of varying degrees. The affected teeth can be very sensitive to air, cold, warm and mechanical stimuli. Toothbrushing may create toothache in these teeth. We therefore suggest that these patients receive intensified prevention with fluoride varnish, a fissure sealing, GIZ, composits, stainless steel crowns or implants. In some cases an interdisciplinary approach with an orthodontist can result in the extraction of the molars

  17. Sodium Picosulfate, Magnesium Oxide, and Anhydrous Citric Acid

    Science.gov (United States)

    Sodium picosulfate, magnesium oxide, and anhydrous citric acid combination powder is used to empty the colon (large ... clear view of the walls of the colon. Sodium picosulfate is in a class of medications called ...

  18. Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ning-bo; CHEN Bai-zhen; HE Xin-kuai; LI Yi-bing

    2006-01-01

    Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuwas synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃ for 4 h. Ammonium carnallite reacted with ammonia at 240℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃ into anhydrous magnesium chloride containing only 0.1% (mass fraction) of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1:4 at high temperature and with the differential pressure of HN3 above 30.5 kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃ into anhydrous magnesium chloride with only 0. 087% (mass fraction) of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn't mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.

  19. 影响口腔正畸治疗患者下颌第三磨牙状态改变的因素分析%Factors influencing the changes of lower third molars' angulation and space/crown width ratio by orthodontic treatment

    Institute of Scientific and Technical Information of China (English)

    李小彤; 张东姝; 杨雁琪

    2011-01-01

    Objective : To investigate the factors which influence the changes of lower third molars ' angulation and space/crown width ratio by orthodontic treatment. Methods : Pretreatment and posttreatment panoramic radiographs of 120 orthodontically treated cases were taken. The lower third molars ' angulation and space/crown width ratio were examined and the relative factors on changes were analyzed. Results : ( 1 ) The changes of the lower third molars' angulation and space/crown width ratio after orthodontic treatment were quite different among the cases. ( 2) The factors which influenced these changes mainly included extraction, mandibular plane angle, angulation and space/crown width ratio of lower third molar before orthodontic treatment. (3) Extraction was the most significantly variable associated with lower third molars' upright ( angulation < 30°) after orthodontic treatment. Conclusion: Orthodontic extraction is helpful to upright the lower third molars and to increase the space for third molars; and the pre-treatment lower third molars ' angulation and space/crown width ratio are important variables for the changes after treatment; cases with lower mandibular plane angle are apt to greater possibility for the lower third molars' upright.%目的:研究影响口腔正畸患者治疗前、后下颌第三磨牙状态改变的因素.方法:利用正畸治疗前、后的全口曲面断层片,测量120例正畸患者的120颗下颌第三磨牙[男37例,女83例,年龄在10~24岁,平均(14.1±3.3)岁]前倾角度和间隙/宽度比值的改变,统计分析影响正畸治疗前、后改变的因素.结果:(1)正畸治疗前、后下颌第三磨牙前倾角度和间隙/宽度比值的改变个体差别较大;(2)影响正畸治疗前、后下颌第三磨牙前倾角度和间隙/宽度比值改变的因素主要有拔牙、下颌平面角、治疗前的前倾角度和间隙/宽度比值(P<0.05),而骨龄和牙龄等因素对下颌第三磨牙状态的

  20. Preparation of anhydrous lanthanum bromide for scintillation crystal growth

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tong; LI Hongwei; ZHAO Chunlei; YU Jinqiu; HU Yunsheng; CUI Lei; HE Huaqiang

    2012-01-01

    This paper reported an efficient and economical method for preparation of anhydrous LaBr3 for scintillation crystal growth.High purity anhydrous LaBr3 powders in large quantities were successfully obtained by stepped dehydration of LaBr3·7H2O using NH4Br as additive.Experiments revealed that adding proper amount of NH4Br could effectively restrain the hydrolysis of LaBr3 during dehydration and thus decreased the yield of deleterious impurity of LaOBr.Optimum preparation conditions,including the amount of NH4Br in use,the dehydration temperature and atmosphere,were investigated by DTA/TG and water/oxygen analysis.The Raman characterization of the as-prepared anhydrous LaBr3 was also presented.

  1. Third molar infections.

    Science.gov (United States)

    Gutiérrez-Pérez, José Luis

    2004-01-01

    Pericoronitis is an infectious disease often associated with the eruption of a third molar. It can be either acute (serous and suppurative) or chronic. Pain is usually the predominant symptom in acute stages, whereas chronic forms of the disease may display very few symptoms. Both present exudate. The infection is multimicrobial, predominantly caused strictly by betalactamase-producing anaerobeic microorganisms. Treatment measures are symptomatic, antimicrobial and surgical. Antimicrobial treatment is indicated for preoperative prophylaxis when there is a high risk of postoperative infection and, during the acute stages of suppurative pericoronitis when surgery must be postponed. First-line treatment in this case consists of amoxicillin with associated clavulanic acid. Although surgical treatment of pericoronitis presenting at the third molar is indicated as a Grade C recommendation for extraction, it is the most common indication for extraction of a retained third molar, owing to the improved quality of life it can offer the patient.

  2. 硅/钴摩尔比对MCM-48介孔分子筛结构性能的影响%Effects of Si/Co Molar Ratios on Textural Property of MCM-48 Mesoporous Molecular Sieve

    Institute of Scientific and Technical Information of China (English)

    周旭平; 赵谦; 吴多林; 纪美茹; 姜廷顺

    2011-01-01

    Using tetraethyl orthosilicate (TEOS) as silica source, cetyltrimethyl ammonium bromide (CTAB) as a template and sodium fluoride as a inorganic salt additive, cobalt-incorporated MCM-48 mesoporous materials (Co-MCM-48) were synthesized by the hydrothermal method. Effects of different molar ratios n(Si):n(Co) in synthesis gel on textural property of the MCM-48 mesoporous materials were investigated. The changes in textural properties were evaluated by the X-ray diffraction (XRD), transmission electron microscopy, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible speetrophotometry (UV-Vis), temperature programmed reduction (TPR), and N2 physical adsorption. Results show that when n(Si):n(Co)=25, the as-synthesized Co-MCM-48 still exhibits a cubic mesoporous framework and has a high specific surface area (1 002.9 m2/g). Characterization by the FTIR, UV-Vis and TPR suggests that cobalt is incorporated into framework of the MCM-48. Specific surface area and pore volume of the synthesized Co-MCM-48 sample gradually decrease with the increase of cobalt content in the synthesis gel; pore size gradually increases and mesoporous ordering begins to deteriorate.%以正硅酸乙酯为硅源、十六烷基三甲基溴化铵为模板、氟化钠为添加剂,水热合成钴掺杂的介孔分子筛(cobalt-containing mesoporous molecular sieve,Co-MCM-48),同时研究合成溶胶中不同摩尔比m(Si):n(Co)对MCM-48介孔材料结构性能的影响.通过X射线粉末衍射、N2吸附-脱附、透射电子显微镜、Fourier变换红外光谱(Fourier transform infrared spectroscopy,FTIR)、紫外-可见光谱(ultraviolet-visible spectrpotometry,UV-Vis)、程序升温还原(temperature programmed reduction,TPR)等方法表征分析样品的结构和性能.结果表明:合成溶胶中n(Si):n(Co)=25时,所得Co-MCM-48仍具有立方介孔结构和较高的比表面积(1 002.9m2/g).FTIR谱、UV-Vis谱及TPR测试等证实:Co已经嵌入MCM-48骨架中,随着

  3. Influence of the Ti concentration and of the Ti:Mo molar ratio, in the efficiency of the {sup 99} Mo - {sup 99m} Tc generator, at basis of gels of titanium molybdates; Influencia de la concentracion de Ti y de la relacion molar Ti:Mo, en la eficiencia del generador {sup 99} Mo - {sup 99m} Tc a base de geles de molibdatos de titanio

    Energy Technology Data Exchange (ETDEWEB)

    Cortes R, O.; Monroy G, F.; Martinez C, T. [Facultad de Quimica, UNAM, 04510 Mexico D.F. (Mexico)]. e-mail: ocielcr@hotmail.com

    2003-07-01

    The {sup 99m} Tc, continues being the radionuclide more used in nuclear medicine to world scale. The production of this radioisotope, is carried out by means of generators {sup 99} Mo/{sup 99m} Tc that get ready commercially with {sup 99} Mo of high specific activity, adsorbed in alumina (2 mg {sup 99} Mo/g alumina) and that they are elutriated every 23 hours. In an alternative way, it is intended to use gels of titanium molybdates, as matrices of this generators. The gels are synthesized starting from solutions of ammonium molybdates and of titanium tetrachloride in aqueous media. These gels allow to incorporate until 25% of molybdenum in their structure, being been able to use {sup 99} Mo of low specific activity that can be obtained starting from the reaction {sup 98} Mo (n, {gamma}) {sup 99} Mo. With the object of producing generators of medium activity, with the base of gels of titanium molybdates, intends in this work, to study the influence of two synthesis parameters of these gels: the concentration of the titanium solutions and the molar ratio Ti: Mo. The decrease of the concentration of the titanium solution, used during the synthesis of the gels, is converted in an efficiency decrease and radionuclide purity of the generators, as well as an increment so much of the volume of elutriation, as of the pH of the elutriates. The gels that contain an major number of titanium moles, regarding the molybdenum moles, present a greater radionuclide purity, but they diminish their efficiency. The best characteristics for the gels synthesis of titanium molybdates are: a molar ratio 1:1 for Ti and Mo, and to use solutions of titanium whose concentration is near at 1 M. (Author)

  4. Process for the production of sodium carbonate anhydrate

    NARCIS (Netherlands)

    Oosterhof, H.; Van Rosmalen, G.M.; Witkamp, G.J.; De Graauw, J.

    2000-01-01

    The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m<3>, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of

  5. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization

    OpenAIRE

    Negre-Barber, A.; Montiel-Company, J. M.; Boronat-Catalá, M.; M. Catalá-Pizarro; Almerich-Silla, J. M.

    2016-01-01

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Ka...

  6. 49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed...

  7. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Maximum anhydrous citric acid permissible for... Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content...

  8. The Cl Isotope Composition of the Moon as evidence for an Anhydrous Mantle (Invited)

    Science.gov (United States)

    Sharp, Z. D.; Shearer, C., Jr.; McKeegan, K. D.; Barnes, J.; Wang, Y.

    2010-12-01

    The chlorine isotope composition of primitive terrestrial basalts and carbonaceous chondrites cover a narrow range centered around 0‰ with a total variation of ± 0.5‰. In contrast, the chlorine isotope composition of bulk samples and in situ ion microprobe analyses of lunar basalts and glasses cover a range of 25‰. Three possibilities were considered to explain the large spread: 1) initial isotopic heterogeneities, 2) devolatilization from solar wind/micrometeorite bombardment, 3) degassing under anhydrous conditions. The first of these possibilities is rejected because the Moon went through an magma ocean stage which would have homogenized any isotopic heterogeneities. To examine surface effects, we chose samples that have extremely different degrees of surface exposure. We find no correlation between the Cl isotope composition and surface exposure. We also conducted a laboratory experiment in which a thin film of NaCl was bombarded with a proton source for 24 hours with no change in Cl isotope composition. The third possibility is that the fractionation is explained by the anhydrous character of the Moon. On Earth, the volatiling Cl species is HCl. HCl is known to preferentially incorporate 37Cl relative to 35Cl due to the high bond strength of the molecule. This is offset by the higher translational velocity of H35Cl, so that overall, there is very little Cl isotope fractionation during degassing. We propose that lunar basalts were anhydrous and the volatile Cl species were metal chlorides, such as ZnCl2, NaCl, FeCl2, etc. The bond strength of metal chlorides and Cl dissolved in a basalt are similar, so that fractionation is caused mainly by volatilization, with the light isotopologue preferentially lost to the vapor phase. This idea is supported by the consistent lower Cl isotope ratios of water soluble salt fraction (~10 ‰ lower) and the lowest lunar Cl isotope values close to those of bulk Earth. The H content of lunar magmas must have been lower

  9. Influence of third molar space on angulation and dental arch crowding.

    Science.gov (United States)

    Hasegawa, Yuh; Terada, Kazuto; Kageyama, Ikuo; Tsuchimochi, Takashi; Ishikawa, Fujiro; Nakahara, Sen

    2013-01-01

    The influence of the third molars on mandibular incisor crowding has been extensively studied but remains controversial. The purpose of this study was to ascertain whether, in Mongolian subjects, the lower third molar can affect anterior crowding and/or the inclination of teeth in the lower lateral segments. Panoramic radiographs, 45° oblique cephalograms, and dental casts were taken from Mongolian subjects (age range 18.3-24.1 years, mean 21.0 years) exhibiting impaction of all four third molars and an Angle Class I molar relationship. The Ganss ratio was calculated using panoramic radiographs, whereas the gonial angle and angulation of lower canines, premolars and molars were measured using 45° oblique cephalograms. Little's index of irregularity was calculated using dental casts. Significant relationships between the angulation of the third and second molars and between the first molars and second premolars were found. Conversely, there was no significant correlation between the angulation of third molars, first premolars and canines. The Ganss ratio calculations showed that the lower first and second molars and the second premolars inclined mesially if there was insufficient space for the lower third molars. However, there was no significant correlation between Little's index of irregularity and third molar angulation. Furthermore, although the third molar influences the lateral segments, no obvious relationship between the third molar and anterior crowding was observed. Therefore, the angulation of the third molar appears not to cause anterior crowding.

  10. Method of synthesis of anhydrous thorium(IV) complexes

    Science.gov (United States)

    Kiplinger, Jaqueline L; Cantat, Thibault

    2013-04-30

    Method of producing anhydrous thorium(IV) tetrahalide complexes, utilizing Th(NO.sub.3).sub.4(H.sub.2O).sub.x, where x is at least 4, as a reagent; method of producing thorium-containing complexes utilizing ThCl.sub.4(DME).sub.2 as a precursor; method of producing purified ThCl.sub.4(ligand).sub.x compounds, where x is from 2 to 9; and novel compounds having the structures: ##STR00001##

  11. Crystalline anhydrous {alpha},{alpha}-trehalose (polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose: A calorimetric study

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Susana S. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: susanapinto@ist.utl.pt; Diogo, Herminio P. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: hdiogo@ist.utl.pt; Moura-Ramos, Joaquim J. [Centro de Quimica-Fisica Molecular, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: mouraramos@ist.utl.pt

    2006-09-15

    The mean values of the standard massic energy of combustion of crystalline anhydrous {alpha},{alpha}-trehalose (C{sub 12}H{sub 22}O{sub 11}, polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose (C{sub 12}H{sub 26}O{sub 13}) measured by static-bomb combustion calorimetry in oxygen, at the temperature T=298.15K, are {delta}{sub c}u{sup o}=-(16434.05+/-4.50)J.g{sup -1} and {delta}{sub c}u{sup o}=-(14816.05+/-3.52)J.g{sup -1}, respectively. The standard (p{sup o}=0.1MPa) molar enthalpy of formation of these compounds were derived from the corresponding standard molar enthalpies of combustion, respectively, {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 22}O{sub 11},cr)=-(2240.9+/-3.9)kJ.mol{sup -1}, and {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 26}O{sub 13},cr)=-(2832.6+/-3.6)kJ.mol{sup -1}. The values of the standard enthalpies of formation obtained in this work, together with data on enthalpies of solution at infinite dilution ({delta}{sub sol}H{sup {approx}}) for crystalline dihydrate and amorphous anhydrous trehalose, allow a better insight on the thermodynamic description of the trehalose system which can provide, together with the future research on the subject, a contribution for understanding the metabolism in several organisms, as well as the phase transition between the different polymorphs.

  12. Characterization by Sem, EDS and micro-Raman of the influence of the molar ratio SiO{sub 2}/Al{sub 2}O{sub 3} and reduction temperature on the system CuZSM5; Caracterizacion por SEM, EDS y micro-Raman de la influencia de la relacion molar SiO{sub 2}/Al{sub 2}O{sub 3} y temperatura de reduccion sobre el sistema CuZSM5

    Energy Technology Data Exchange (ETDEWEB)

    Chavez R, F. [Instituto Politecnico Nacional, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, 07738 Mexico D. F. (Mexico); Rodriguez I, I. [Universidad de la Habana, Instituto de Ciencia y Tecnologia de Materiales, Zapata y G. s/n, 10400 La Habana (Cuba); Petranovskii, V., E-mail: fchavez@esfm.ipn.mx [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 14, 22800 Ensenada, Baja California (Mexico)

    2014-07-01

    The morphological and spectroscopic changes caused by reduction of ion-exchanged CuZSM5 samples with SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios (MR) of 30 and 70 in H{sub 2} flow at 150 and 350 grades C are discussed. the nominal copper loading was of 1% by weight. Scanning electron microscopy of CuZSM5 sample set showed that the treatment in reducing atmosphere at 350 grades C produces particle agglomeration and smoother surface texture that treatment at 150 grades C, this effect was more pronounced for the sample with MR 30. Furthermore, the particles corresponding to the sample with MR 30 are of irregular shape and have rough texture (cubic or rectangular crystals, protrusions) while the particles of the sample with MR 70 are in the majority of spherical smooth texture (leaf-shaped crystals/platelet, reclining). Energy Dispersive X-ray spectroscopy elemental analysis reveals a heterogeneous distribution of copper as well other elements in each sample. The micro-Raman spectroscopy shows some changes in the vibrational modes for the studied samples. (Author)

  13. Molar Incisor Hypomineralization.

    Science.gov (United States)

    Rao, Murali H; Aluru, Srikanth C; Jayam, Cheranjeevi; Bandlapalli, Anila; Patel, Nikunj

    2016-07-01

    Molar incisor hypomineralization (MIH) is a developmental defect affecting teeth. High prevalence rates of MIH and its clinical implications are significant for both the patients and clinicians. A wide variation in defect prevalence (2.4-40.2%) is reported. It seems to differ with regions and various birth cohorts. Some of the recent prevalence studies are tabulated. Patient implications include hypersensitive teeth, rapid progression of caries, mastication impairment due to rapid attrition, and esthetic repercussions. Implications for clinicians include complexity in treatment planning and treatment implementation, poor prognosis of the restorations, difficulty in achieving pain control during treatment, and behavior management problems. Intention of this paper is to review the etio-pathogenesis, prevalence, clinical features, diagnostic features, and eventually present a sequential treatment approach, i.e., in accordance with current clinical practice guidelines.

  14. 醇醛物质的量比对不饱和醛催化氢转移反应的影响%Influence of isopropanol/citral molar ratio on citral hydrogen transfer reaction

    Institute of Scientific and Technical Information of China (English)

    周勤; 陈希慧

    2011-01-01

    The influence of isopropanol/citral ratio on the reaction rate of citral and isopropanol hydrogen transfer reaction catalyzed by ZrO2/SiO2 was investigated. The results showed that the boiling point of reaction mixtures lowered with the increase of isopropanol/citral ratio under the experimental condition.The conversion of citral and selectivity to aim product were obviously influenced by isopropanol/citral ratio.The change of boiling point caused by the change of isopropanol/citral ratio could be the main influencing factor of the reaction rate. The optimum isopropanol/citral mole ratio of 5 and the experimental apparent activation energy of 100.5 kJ · mol -1 were attained.%探讨了ZrO2/SiO2催化柠檬醛和异丙醇的氢转移反应醇醛物质的量比对反应速率的影响.结果表明,实验条件下,反应混合物的沸点随醇醛物质的量比的增大而降低;柠檬醛转化率和目标产物选择性明显受醇醛物质的量比的影响,醇醛物质的量比变化导致混合物沸点的改变可能是影响反应速率的主要因素.研究条件下,反应最适宜的醇醛物质的量比为5,表观活化能为100.5 kJ·mol-1.

  15. Treating Intraradicular Pockets of molars

    Directory of Open Access Journals (Sweden)

    H. Lotfizade

    1987-10-01

    Full Text Available It appears that until bone graft has not achieved 100% success, intraradicular diseases remain controversial and therefore, different treatment plans are suggested for them. Treating intraradicular diseases depend on many factors: maxillary molars are more prone to bone loss and have worse prognosis. To assess prognosis more carefully these factors should be considered: 1 bone loss: its apical depth, local or generalized 2 bone condition: buccal, lingual, mesial and distal aspects 3 tooth mobility: grades 2 and 3 have not good prognosis. Crown root ratio is also important. 4 the angle of divergence of roots: the more the roots are divergent, the better the prognosis would be. 5adjacent teeth health 6tooth position in jaws 7 age and general health of the patients 8 oral hygiene In general, teeth with 2 roots can be treated more effectively than 3 root ones. Maxillary first premolars are exceptions that do not respond to the treatments positively. We should look forward to the future investigations and findings.

  16. Anhydrous crystals of DNA bases are wide gap semiconductors.

    Science.gov (United States)

    Maia, F F; Freire, V N; Caetano, E W S; Azevedo, D L; Sales, F A M; Albuquerque, E L

    2011-05-07

    We present the structural, electronic, and optical properties of anhydrous crystals of DNA nucleobases (guanine, adenine, cytosine, and thymine) found after DFT (Density Functional Theory) calculations within the local density approximation, as well as experimental measurements of optical absorption for powders of these crystals. Guanine and cytosine (adenine and thymine) anhydrous crystals are predicted from the DFT simulations to be direct (indirect) band gap semiconductors, with values 2.68 eV and 3.30 eV (2.83 eV and 3.22 eV), respectively, while the experimentally estimated band gaps we have measured are 3.83 eV and 3.84 eV (3.89 eV and 4.07 eV), in the same order. The electronic effective masses we have obtained at band extremes show that, at low temperatures, these crystals behave like wide gap semiconductors for electrons moving along the nucleobases stacking direction, while the hole transport are somewhat limited. Lastly, the calculated electronic dielectric functions of DNA nucleobases crystals in the parallel and perpendicular directions to the stacking planes exhibit a high degree of anisotropy (except cytosine), in agreement with published experimental results.

  17. A New Thickener for CO2 Anhydrous Fracturing Fluid

    Directory of Open Access Journals (Sweden)

    Zhang Jian

    2015-01-01

    Full Text Available CO2 dry fracturing technology is well-known for its advantages. Little water is used in this technology, which is able to ease the pressure of consumption on water resources. Many abroad theoretical researches, laboratory experiments and field tests have been taken to explore the yield mechanism, the adaptability and the technology of pure liquid CO2 fracturing. These achievements have been applied to a variety of reservoirs transformation and improven the effectiveness of stimulation treatment in a degree. The researches and studies in the domestic didn’t get popular until recent years. Thus, this article firstly introduces the main development and application about pure CO2 anhydrous fracturing technology, and sums up the effect and evaluation of its fluid through application examples both in the domestic and abroad. However, although this technology has many excellent qualities, but systematic studies indicate that its proppant-carrying capacity is less competitive because of the low viscosity of pure CO2 liquid and other reasons. In a consequence, it is necessary to develop an appropriate thickener for CO2 anhydrous fracturing fluid to improve its carrying capacity. Then this article describes some studies of previous scholars about CO2 thickener. Then we put forward our own research ideas and transform it into actual experiments. Thanks to the valid performances of these tests, we successfully develop a thickener X and cosolvent B.

  18. Formulation and in vitro evaluation of theophylline anhydrous bioadhesive tablets

    Directory of Open Access Journals (Sweden)

    Deshmukh V

    2009-01-01

    Full Text Available The aim of the current study was to design oral controlled release (CR theophylline anhydrous bioadhesive tablets and to optimize the drug release profile and in vitro bioadhesion strength. Different types of natural hydrophilic polymers such as xanthun gum, locust bean gum, guar gum, karaya gum, and their combinations were used to formulate matrix tablets. Tablets of anhydrous theophylline were prepared by the direct compression method and were subjected to in vitro drug dissolution for 12 hours using the USP dissolution apparatus basket type at a speed of 100 rpm and temperature of 37 ± 0.5°C using gastric fluid (pH 1.2. The bioadhesive strength of the tablets was measured as the force of detachment against the porcine gastric mucosa. The in vitro release study as well as the retention time of the bioadhesive tablets on the mucous membrane were investigated to develop a bioadhesive polymer-based CR delivery system and to evaluate the performance of such a delivery device. The combination of karaya gum:guar gum (6:4 tablet showed a greater bioadhesive strength as compared with a single gum and other gum combination tablets. Karaya gum:guar gum-loaded tablets were not discharged from the mucous membrane and were dissolved in the gastric fluid. An increase in the gum concentration increases the drug release profile beyond 12 hours whereas there is no significant effect of gum concentration on the bioadhesive strength of the tablet.

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

    OpenAIRE

    2013-01-01

    Purpose This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Materials and Methods Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated...

  20. 7 CFR 58.715 - Cream, plastic cream and anhydrous milkfat.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cream, plastic cream and anhydrous milkfat. 58.715 Section 58.715 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... Service 1 Quality Specifications for Raw Material § 58.715 Cream, plastic cream and anhydrous...

  1. Lactate and the lactate-to-pyruvate molar ratio cannot be used as independent biomarkers for monitoring brain energetic metabolism: a microdialysis study in patients with traumatic brain injuries.

    Directory of Open Access Journals (Sweden)

    Juan Sahuquillo

    Full Text Available BACKGROUND: For decades, lactate has been considered an excellent biomarker for oxygen limitation and therefore of organ ischemia. The aim of the present study was to evaluate the frequency of increased brain lactate levels and the LP ratio (LPR in a cohort of patients with severe or moderate traumatic brain injury (TBI subjected to brain microdialysis monitoring to analyze the agreement between these two biomarkers and to indicate brain energy metabolism dysfunction. METHODS: Forty-six patients with an admission Glasgow coma scale score of ≤13 after resuscitation admitted to a dedicated 10-bed Neurotraumatology Intensive Care Unit were included, and 5305 verified samples of good microdialysis data were analyzed. RESULTS: Lactate levels were above 2.5 mmol/L in 56.9% of the samples. The relationships between lactate and the LPR could not be adequately modeled by any linear or non-linear model. Neither Cohen's kappa nor Gwet's statistic showed an acceptable agreement between both biomarkers to classify the samples in regard to normal or abnormal metabolism. The dataset was divided into four patterns defined by the lactate concentrations and the LPR. A potential interpretation for these patterns is suggested and discussed. Pattern 4 (low pyruvate levels was found in 10.7% of the samples and was characterized by a significantly low concentration of brain glucose compared with the other groups. CONCLUSIONS: Our study shows that metabolic abnormalities are frequent in the macroscopically normal brain in patients with traumatic brain injuries and a very poor agreement between lactate and the LPR when classifying metabolism. The concentration of lactate in the dialysates must be interpreted while taking into consideration the LPR to distinguish between anaerobic metabolism and aerobic hyperglycolysis.

  2. Size of the lower third molar space in relation to age in Serbian population

    Directory of Open Access Journals (Sweden)

    Zelić Ksenija

    2013-01-01

    Full Text Available Background/Aim. It is considered that the shortage of space is the major cause of the third molar impaction. The aim of this study was to establish the frequency of insufficient lower third molar eruption space in Serbian population, to question the differences in this frequency in the subjects of different age, to determine the influence of the lower third molar space (retromolar space size on third molar eruption, and to investigate a possible correlation between the size of gonial angle and the space/third molar width ratio. Methods. Digital orthopantomograms were taken from 93 patients divided into two groups: early adult (16-18 years of age and adult (18-26 patients. Retromolar space, mesiodistal third molar crown width, gonial angle and eruption levels were measured. Results. The space/third molar width in early adult subjects was smaller (p < 0.0001 and insufficient space was significantly more frequent (p = 0.0003 than in adult patients. Considerably more third molars erupted in case of enough space in both age groups (p < 0.0001. There was no difference between the means of gonial angle size in relations to the available space. Conclusions. The retromolar space/third molar width ratio is more favorable in adult subjects. Gonial angle is not in correlation with the retromolar space/third molar width ratio. [Projekat Ministarstva nauke Republike Srbije, br. 45005

  3. Association between enamel hypoplasia and dental caries in primary second molars and permanent first molars: A 3-year follow-up study

    Directory of Open Access Journals (Sweden)

    Sakeenabi Basha

    2016-01-01

    Full Text Available Context: Enamel hypoplasia is a defect caused by disturbances during enamel formation. These defects in the enamel present important clinical significance as they predispose a tooth to dental caries. Aim: The aim of this study was to assess the longitudinal relationships between enamel hypoplasia and caries experience of primary second molars and permanent first molars. Materials and Methods: The study sample consisted of 765 subjects who underwent dental examinations at both ages 6 and 9 by the calibrated examiner. Primary second molars and permanent first molars were scored for the presence of enamel hypoplasia for each participant. Caries presence and number of decayed and filled surfaces (dfs and DFS were determined at ages 6 and 9. The relationships between enamel hypoplasia and caries experience were assessed using multivariable regression models. Results: At the tooth level, 2.8% and 3.5% of children had hypoplasia on primary second molars and permanent first molars respectively. Multivariable logistic regression analyses showed that children with enamel hypoplasia were at a significantly higher risk of caries at both ages 6 (odds ratio, OR = 5.27 for primary second molars and OR = 3.21 for permanent first molars and age 9 (OR = 3.45 for primary second molars and OR = 4.57 for permanent first molars, and that a statistically significant association was seen with caries incidence (OR = 2.08 for primary second molars and OR = 2.87 for permanent first molars. Conclusion: Enamel hypoplasia appears to be a significant risk factor for caries in both primary second molars and permanent first molars and should be considered in caries risk assessment.

  4. Complications of third molar surgery.

    Science.gov (United States)

    Bouloux, Gary F; Steed, Martin B; Perciaccante, Vincent J

    2007-02-01

    This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Injuries of the inferior alveolar and lingual nerves are significant issues that are discussed separately in this text. Surgical removal of third molars is often associated with postoperative pain, swelling, and trismus. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical history, oral contraceptives, presence of pericoronitis, poor oral hygiene, smoking, type of impaction, relationship of third molar to the inferior alveolar nerve, surgical time, surgical technique, surgeon experience, use of perioperative antibiotics, use of topical antiseptics, use of intra-socket medications, and anesthetic technique. Complications that are discussed further include alveolar osteitis, postoperative infection, hemorrhage, oro-antral communication, damage to adjacent teeth, displaced teeth, and fractures.

  5. Effect of Ce/Zr molar ratio on the performance of Cu–Ce{sub x}–Zr{sub 1−x}/TiO{sub 2} catalyst for selective catalytic reduction of NO{sub x} with NH{sub 3} in diesel exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaoliang [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Gong, Cairong, E-mail: gcr@tju.edu.cn [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Lv, Gang; Bin, Feng; Song, Chonglin [State Key Laboratory of Engines, Tianjin University, Tianjin 300072 (China)

    2014-12-15

    Graphical abstract: The Cu–Ce{sub 0.25}–Zr{sub 0.75}/TiO{sub 2} catalyst exhibited excellent SCR activity at 165–450 °C within the range of exhaust temperatures of diesel engines. - Highlights: • Cu–Ce{sub x}–Zr{sub 1−x}/TiO{sub 2} catalysts were prepared by a wet impregnation method. • The property for NH{sub 3}-selective catalytic reduction of NO{sub x} were investigated. • The Ce/Zr molar ratio had effects on the performance of Cu–Ce–Zr/TiO{sub 2} catalysts. • The Cu–Ce{sub 0.25}–Zr{sub 0.75}/TiO{sub 2} sample exhibited 100% NO{sub x} conversion between 165 °C and 450 °C. • The factors that govern the activity enhancement were extensively investigated. - Abstract: Copper–cerium–zirconium catalysts loaded on TiO{sub 2} prepared by a wet impregnation method were investigated for NH{sub 3}-selective catalytic reduction of NO{sub x}, aiming to study the effects of the Ce/Zr molar ratio on the performance of Cu–Ce–Zr/TiO{sub 2} catalysts. The Cu–Ce{sub 0.25}–Zr{sub 0.75}/TiO{sub 2} sample exhibited nearly 100% NO{sub x} conversion over a wide temperature range (165–450 °C), which is strikingly superior to that of Cu/TiO{sub 2} (210–389 °C) within the range of exhaust temperatures of diesel engines. The factors that govern the activity enhancement were extensively investigated by using a series of characterization techniques, namely X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H{sub 2}-TPR). The results showed that the addition of zirconium and/or cerium refined the copper dispersion, prevented copper crystallization and partially incorporated the copper ions into the zirconia (ceira) lattice, which led to enhance the redox abilities of Cu–Ce–Zr/TiO{sub 2} catalysts.

  6. Novel anhydrous emulsions: formulation as controlled release vehicles.

    Science.gov (United States)

    Suitthimeathegorn, Orawan; Jaitely, Vikas; Florence, Alexander T

    2005-07-25

    Novel anhydrous emulsions, which may offer some advantages as depot or reservoir vehicles for lipophilic drugs in controlled delivery systems, were formulated using castor oil as the disperse phase and dimethicone or cyclopentasiloxane as the continuous phase. Among the emulsifiers studied only silicone surfactants (cyclomethicone/dimethicone copolyols) which were miscible in silicone oil stabilized the emulsions. Cyclomethicone/PEG/PPG-18/18 Dimethicone and Cyclopentasiloxane/PEG/PPG-18/18 Dimethicone were more effective in lowering the interfacial tension between castor oil and both dimethicone and cyclopentasiloxane. Emulsions formulated using either of these two surfactants were found to be stable against phase separation and exhibited least globule growth over 168 h. The average particle size was found to be 2-6 microm in these systems formed by probe sonication. Slow release patterns of 3H-dehydroepiandrosterone (DHEA) and 3H-dexamethasone solubilized in the disperse castor oil phase into an aqueous dialyzing medium were observed over 48 h.

  7. Periodic quantum chemical studies on anhydrous and hydrated acid clinoptilolite.

    Science.gov (United States)

    Valdiviés Cruz, Karell; Lam, Anabel; Zicovich-Wilson, Claudio M

    2014-08-07

    Periodic quantum chemistry methods as implemented in the crystal09 code were considered to study acid clinoptilolite (HEU framework type), both anhydrous and hydrated. The most probable location of acid sites and water molecules together with other structural details has been the object of particular attention. Calculations were performed at hybrid and pristine DFT levels of theory with a VDZP quality basis set in order to compare performances. It arises that PBE0 provides the best agreement with experimental data as concerns structural features and the most stable Al distribution in the framework. The role of the water molecule distribution in the stability of the systems, the most probable structure that they induce in the material, and their eventual influence on further chemical modification processes, such as dealumination, are discussed in detail. Results show that, apart from the usually considered interactions of water molecules with the zeolite framework, that is, a H-bond with Brönsted acid sites and coordination with framework Al as Lewis ones, it is necessary to consider cooperation of other weaker effects so as to fully understand the hydration effect in this kind of materials.

  8. 酸性条件下氮素形态对西红柿根系释放羟基的影响%Effect of NO3-/NH4+ Molar Ratio on Release of Hydroxyl from Tomato Roots in Acidic Culture Solutions

    Institute of Scientific and Technical Information of China (English)

    万青; 徐仁扣; 黎星辉

    2011-01-01

    为研发酸化土壤的生物修复技术,本文用水培实验和电位滴定方法研究了酸性条件下氮素形态对西红柿根系释放羟基的影响,结果表明,在初始pH为4.0、NO3/NH4+比为15:1、5:1、1:1和1:5的营养液中,由于西红柿对NO3--N的偏好吸收导致根系释放羟基,培养液pH升高.培养1周后4个NO3-/NH4+比培养液pH分别升高了1.60、1.15、0.57和0.29,与西红柿对NO3--N的吸收量和羟基释放量的大小一致.当西红柿生长在初始pH为5.0营养液中时,仅NO3-/NH4+比为15:1和5:1体系中西红柿根系释放羟基,导致培养液pH升高;在NO3-/NH4+比为1:1和1:5体系中西红柿根系释放质子,导致培养液pH降低.初始pH5.0条件下西红柿吸收的NO3--N低于初始pH4.0条件下的,其根系释放的羟基量也低于pH4.0体系中的.这些结果说明低pH条件有利于西红柿对NO3--N的吸收,西红柿根系也会释放更多的羟基.因此可以根据西红柿在强酸性条件下对NO3--N的偏好吸收和根系释放羟基的特点对酸化土壤进行生物修复.%In order to develop bioremediation technology for acidified soils, effect of NO3-/NH4+ molar ratio on release of hydroxyl from tomato roots under acidic conditions was investigated with solution culture experiments and automatic potentiometric titrations. When the initial pH was 4.0 and NO3-/NH4+ molar ratios were 15:1, 5:1,1:1 and 1:5, tomato took up more nitrate from culture solution and its roots released hydroxyl into culture solutions, and thus led to the increase of solution pH. The pH of culture solutions with NCV/NR/ molar ratios of 15:1, 5:1, 1:1 and 1:5 was increased by 1.60, 1.15, 0.57 and 0.29 units after 7 days of tomato cultivation. The change of solution pH was consistent with the amounts of nitrate absorbed by tomato and hydroxyl released by its roots. When tomato grew in the culture solution with initial pH of 5.0, its roots released hydroxyl in the solutions with NO3-/NH4+molar ration of

  9. Using microkinetic analysis to search for novel anhydrous formaldehyde production catalysts

    DEFF Research Database (Denmark)

    Li, Han-Jung; Lausche, Adam C.; Peterson, Andrew A.

    2015-01-01

    Abstract Direct dehydrogenation of methanol to produce anhydrous formaldehyde is investigated using periodic density functional theory (DFT) and combining the microkinetic model to estimate rates and selectivities on stepped (211) surfaces under a desired reaction condition. Binding energies of r...

  10. Activation of Anhydrate Phosphogypsmn by K2SO4 and Hemihydrate Gypsum

    Institute of Scientific and Technical Information of China (English)

    YANG Min; QIAN Jueshi

    2011-01-01

    Lime pretreated phosphogypsum(PG) was calcined at 500 ℃ to produce anhydrate gypsum cement.Due to the slow hydration of anhydrate gypsum,additives,K2SO4 and hemihydrate gypsum were selected to accelerate the hydration of anhydrate.The hydration characteristics,the resistance to hydrodynamic water,and the mineralogical studies were investigated.The experimental results suggest that activated by K2SO4 and hemihydrate,anhydrate PG hydrates much more rapidly than that in the presence of only K2SO4 or in the absence of additives.The binder has proper setting time,good strength development,and relatively better resistance to water.The hardened binder has hydrated products of rod or stick like shaped dihydrate gypsum crystals.

  11. Study on the Stability of DeoxyArbutin in an Anhydrous Emulsion System

    OpenAIRE

    Chiu-Wen Chen; Shu-Mei Lee; Yi-Shyan Chen; Pey-Shiuan Wu; Nai-Fang Chang; Chao-Hsun Yang; Chih-Chien Lin

    2011-01-01

    The skin-whitening agent, deoxyArbutin, is a potent tyrosinase inhibitor that is safer than hydroquinone and arbutin. However, it is thermolabile in aqueous solutions, where it decomposes to hydroquinone. Pharmaceutical and cosmetic emulsions are normally oil-in-water (o/w) or water-in-oil (w/o) systems; however, emulsions can be formulated with no aqueous phase to produce an anhydrous emulsion system. An anhydrous emulsion system could offer a stable vehicle for compounds that are sensitive ...

  12. Water in Nominally Anhydrous Minerals from Nakhlites and Shergottites

    Science.gov (United States)

    Peslier, Anne H.

    2013-01-01

    Estimating the amount of water in the interior of terrestrial planets has tremendous implications on our understanding of solar nebula evolution, planet formation and geological history, and extraterrestrial volcanism. Mars has been a recent focus of such enquiry with complementary datasets from spacecrafts, rovers and martian meteorite studies. In planetary interiors, water can be dissolved in fluids or melts and hydrous phases, but can also be locked as protons attached to structural oxygen in lattice defects in nominally anhydrous minerals (NAM) such as olivine, pyroxene, or feldspar [1-3]. Measuring water in Martian meteorite NAM is challenging because the minerals are fragile and riddled with fractures from impact processes that makes them break apart during sample processing. Moreover, curing the sample in epoxy causes problems for the two main water analysis techniques, Fourier transform infrared spectrometry (FTIR) and secondary ionization mass spectrometry (SIMS). Measurements to date have resulted in a heated debate on how much water the mantle of Mars contains. SIMS studies of NAM [4], amphiboles [5], and apatites [6-8] from Martian meteorites report finding enough water in these phases to infer that the martian mantle is as hydrous as that of the Earth. On the other hand, a SIMS study of glass in olivine melt inclusions from shergottites concludes that the Martian mantle is much drier [9]. The latter interpretation is also supported by the fact that most martian hydrous minerals generally have the relevant sites filled with Cl and F instead of H [10,11]. As for experimental results, martian basalt compositions can be reproduced using water as well as Cl in the parent melts [12,13]. Here FTIR is used to measure water in martian meteorite minerals in order to constrain the origin of the distribution of water in martian meteorite phases.

  13. CANINE ECTOPIC TREATMENT WITH FIRST MOLAR EXTRACTION

    Directory of Open Access Journals (Sweden)

    Angelica Margo

    2015-06-01

    Full Text Available Decision to extract or not and the type of tooth must be analyzed carefully in orthodontic treatment. Preferable tooth to be extracted was the tooth with large caries or restoration. Usually the type of tooth to be extracted was second molar (if the third molar appears, incisor, first molar, and combination of several teeth. Orthodontic treatment with molar extraction is more difficult to treat and the result is usually compromise. There are several considerations in extracting first molar such as tooth with large caries or restoration, hypoplasia, periapical disease, large discrepancy, high maxilla-mandibular plane angle, and cases with anterior open bite. Nowadays, orthodontic cases with molar extraction do not prolong the treatment time compared to premolar extraction case, but the anchorage system must be considered carefully. The present case was treated with extraction of first molar to solve anterior crowding with maximum anchorage at the upper jaw and using Nance Holding Appliance.

  14. Study on the Stability of DeoxyArbutin in an Anhydrous Emulsion Systemy

    Directory of Open Access Journals (Sweden)

    Chiu-Wen Chen

    2011-09-01

    Full Text Available The skin-whitening agent, deoxyArbutin, is a potent tyrosinase inhibitor that is safer than hydroquinone and arbutin. However, it is thermolabile in aqueous solutions, where it decomposes to hydroquinone. Pharmaceutical and cosmetic emulsions are normally oil-in-water (o/w or water-in-oil (w/o systems; however, emulsions can be formulated with no aqueous phase to produce an anhydrous emulsion system. An anhydrous emulsion system could offer a stable vehicle for compounds that are sensitive to hydrolysis or oxidation. Therefore, to enhance the stability of deoxyArbutin in formulations, we chose the polyol-in-silicone, anhydrous emulsion system as the basic formulation for investigation. The quantity of deoxyArbutin and the accumulation of hydroquinone in both hydrous and anhydrous emulsions at various temperatures were analyzed through an established high performance liquid chromatographic (HPLC method. The results indicated that water increased the decomposition of deoxyArbutin in the formulations and that the polyol-in-silicone, oil-based, anhydrous emulsion system provided a relatively stable surrounding for the deoxyArbutin that delayed its degradation at 25 °C and 45 °C. Moreover, the composition of the inner hydrophilic phase, containing different amounts of glycerin and propylene glycol, affected the stability of deoxyArbutin. Thus, these results will be beneficial when using deoxyArbutin in cosmetics and medicines in the future.

  15. Effect of nitrapyrin on emission of nitrous oxide from soil fertilized with anhydrous ammonia

    Science.gov (United States)

    Bremner, J. M.; Breitenbeck, G. A.; Blackmer, A. M.

    1981-04-01

    Field studies using a chamber technique to measure emissions of nitrous oxide (N2O) showed that the N2O emissions induced by fertilization of soil with anhydrous ammonia (180 kg N ha-1) were markedly reduced by addition of nitrapyrin [2-chloro-6-(trichloromethyl)-pyridine] to this fertilizer. The emission of N2O induced by application of anhydrous ammonia in the fall was reduced 63% by addition of nitrapyrin at the rate of 0.56 kg ha-1. The corresponding reduction when nitrapyrin was added to anhydrous ammonia applied in the spring was 87%. These observations indicate that nitrapyrin has potential value for reduction of the N2O emissions induced by nitrogen fertilization of soils and the possible adverse effects of these emissions on our climate.

  16. Pretreatment of corn stover using low-moisture anhydrous ammonia (LMAA) process.

    Science.gov (United States)

    Yoo, Chang Geun; Nghiem, Nhuan P; Hicks, Kevin B; Kim, Tae Hyun

    2011-11-01

    A simple pretreatment method using anhydrous ammonia was developed to minimize water and ammonia inputs for cellulosic ethanol production, termed the low moisture anhydrous ammonia (LMAA) pretreatment. In this method, corn stover with 30-70% moisture was contacted with anhydrous ammonia in a reactor under nearly ambient conditions. After the ammoniation step, biomass was subjected to a simple pretreatment step at moderate temperatures (40-120°C) for 48-144 h. Pretreated biomass was saccharified and fermented without an additional washing step. With 3% glucan loading of LMAA-treated corn stover under best treatment conditions (0.1g-ammonia+1.0 g-water per g biomass, 80°C, and 84 h), simultaneous saccharification and cofermentation test resulted in 24.9 g/l (89% of theoretical ethanol yield based on glucan+xylan in corn stover).

  17. An unrealistic drift in assay on anhydrous basis towards content limit

    Directory of Open Access Journals (Sweden)

    Shivram K

    2009-01-01

    Full Text Available The assay on anhydrous basis is a mathematically derived value from an experimental results of assay and water content tests. The results of assay and water content tests are determined, separately, on as-is basis. The industry-accepted formula for assay on anhydrous basis = (assay on as-is basis×100/(100-%water. Statistically, the two variables involved in accepted formula are assay on as-is basis and water to obtain assay on anhydrous basis. The experimental errors associated with these two variables propagate in assay on anhydrous basis. The error propagates either in constructive or destructive mode. The constructive mode of error propagation is combination of positive error of assay on as-is basis and positive error of water or negative error of assay on as-is basis and negative error of water. The constructive mode of error propagation has more impact on assay on anhydrous basis values and its confidence interval. The destructive mode of error propagation is combination of a positive error of assay on as-is basis and a negative error of water or vice versa. The destructive mode of error propagation has lesser impact on assay on anhydrous basis values and its confidence interval in comparison to the constructive mode of error propagation. In accepted formula said above, the constructive or destructive error propagation causes unrealistic drift of assay on anhydrous basis towards either lower or higher side of content limit of substance. The risk of rejection of pharmaceutical use substance is higher based on assay test results that results are calculated from industry-accepted formula. The purpose of the study is to propose an alternative formula to overcome limitations of accepted formula and justify the propagation of errors in realistic way. We have given three examples of pharmaceutical use substances to emphasise the above proposition. The proposed formula for assay on anhydrous basis= (assay on as-is basis×F/(F-%water in which F is

  18. MB2 in maxillary second molar

    Directory of Open Access Journals (Sweden)

    Prakash R

    2007-01-01

    Full Text Available Occurrence of the second mesiobuccal canal (MB2 is a frequent finding. Literary reports have shown it to be found more in the cases of the maxillary first molar. However the maxillary second molars have also been found with this variation in a number of canals. This paper presents a case report on the occurrence of a second mesiobuccal canal or the MB2 in the maxillary second molar.

  19. Corn yield and nitrate loss in subsurface drainage affected by timing of anhydrous ammonia application

    Science.gov (United States)

    Surprisingly little research has examined the corn yield, N use efficiency, and water quality implications of N fertilizer timing. We applied anhydrous ammonia either in the fall after harvest (F) at 196 kg ha-1, or in the spring before planting (PP) or as an early sidedress (SD) at rates of 168 kg ...

  20. Melt-processed anhydrous proton exchange membranes for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Mokrini, A.; Siu, A.; Diaz, G.; Crites, C.; Robitaille, L. [National Research Council of Canada, Boucherville, PQ (Canada). Industrial Materials Inst.

    2009-07-01

    The current benchmark materials for proton exchange membrane (PEM) fuel cells are perfluorosulfonic acid resins (PFSA) because of their excellent stability and proton conductivity of 0.1 s/cm at 80 degrees C when fully humidified. However their performance decreases significantly at higher temperatures and low humidity. This paper presented the properties of nanocomposite PEMs incorporating a series of anhydrous charge carriers that are viable candidates for making water-free membranes that can operate at temperatures above 120 degrees C. However, the volatility or leaching of these anhydrous charge carriers could prevent them from being successfully used in open electrochemical systems. Therefore, in this study, the anhydrous charge carriers were immobilized on inorganic nanoparticles and incorporated into PEMs formulations. Nanoparticles with diameters ranging from 50-200 nm were synthesized via a sol-gel process and the desired anhydrous charge carriers immobilized on their surfaces. Nanocomposite PEMs were prepared using melt-processing technologies, by blending the grafted nanoparticles and fluorinated polymers such as poly (vinylidene fluoride) (PVDF) and ionomers such as Nafion. This paper presented the properties of the PEMs developed as a function of nanoparticles size and content, as well as the proton conductivity at controlled temperature and RH.

  1. Does fixed retention prevent overeruption of unopposed mandibular second molars in maxillary first molar extraction cases?

    Directory of Open Access Journals (Sweden)

    Christos Livas

    2016-01-01

    Full Text Available Abstract Background The objective of this study was to investigate whether multistranded fixed retainers prevented overeruption of unopposed mandibular second molars in maxillary first molar extraction cases. Methods The panoramic radiographs of 65 Class II Division 1 Caucasian Whites (28 females, 37 males consecutively treated with bilateral maxillary first molar extraction and the Begg technique, and with records taken after treatment (T1 and in retention (T2, were withdrawn from private practice records. After appliance removal, mandibular second molars were retained with sectional wires till at least T2 in case of lack of occlusal contact with the antagonist. The subjects were assigned to study-retention and control-nonretention groups based on the retention status of mandibular second molars. Radiographic analysis was carried out to determine inclination of mandibular molars and the resulting movement of second molar centroids. Parametric and nonparametric tests were performed to assess the changes between T1 and T2. Results No statistically significant differences in molar inclination were observed between groups and timepoints (P > 0.05. There were no statistically significant differences in molar movement percentages (P > 0.05 irrespective of whether fixed retention had been used or not. Conclusions No significant eruption occurred in unopposed mandibular second molars bonded with fixed sectional retainers compared to molars partially occluded with the antagonists without fixed retention. Given the study limitations, fixed retention should be considered with caution in restricting tooth overeruption in unopposed molars.

  2. Dentinal innervation of impacted human third molars.

    Science.gov (United States)

    Lilja, J; Fagerberg-Mohlin, B

    1984-12-01

    Five totally impacted third molars were studied in the transmission electron microscope for the presence of nervous structures in the dentin before eruption. In contradiction to earlier studies available, nervous structures were found in the predentin and the dentin of the impacted third molars in different parts of the crown and also in the predentin of the root.

  3. Compressibility of hydrated and anhydrous sodium silicate-based liquids and glasses, as analogues for natural silicate melts, by Brillouin scattering spectroscopy

    Science.gov (United States)

    Tkachev, Sergey Nikolayevich

    high pressures. Thus, water-rich silica-bearing solutions present at depth are likely to be difficult to seismically distinguish from anhydrous silicate melts based solely upon their sound velocities. The data on water-bearing compounds allow the pressure dependence of the partial molar volume of water to be assessed to upper mantle depths.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong [Chiang Mai University, Chiang Mai (Thailand)

    2013-12-15

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

  5. Pulpectomy procedures in primary molar teeth

    Directory of Open Access Journals (Sweden)

    Hany Mohamed Aly Ahmed

    2014-01-01

    Full Text Available Premature loss of primary molars can cause a number of undesirable consequences including loss of arch length, insufficient space for erupting premolars and mesial tipping of the permanent molars. Pulpectomy of primary molar teeth is considered as a reasonable treatment approach to ensure either normal shedding or a long-term survival in instances of retention. Despite being a more conservative treatment option than extraction, efficient pulpectomy of bizarre and tortuous root canals encased in roots programmed for physiologic resorption that show close proximity to developing permanent tooth buds presents a critical endodontic challenge. This article aims to provide an overview of this treatment approach, including partial and total pulpectomy, in primary molar teeth. In addition, the recommended guidelines that should be followed, and the current updates that have been developed, while commencing total pulpectomy in primary molars are discussed.

  6. General technique of third molar removal.

    Science.gov (United States)

    Farish, Sam E; Bouloux, Gary F

    2007-02-01

    The most commonly performed surgical procedure in most oral and maxillofacial surgery practices is the removal of impacted third molars. Extensive training, skill, and experience allow this procedure to be performed in an atraumatic fashion with local anesthesia, sedation, or general anesthesia. The decision to remove symptomatic third molars is not usually difficult, but the decision to remove asymptomatic third molars is sometimes less clear and requires clinical experience. A wide body of literature (discussed elsewhere in this issue) attempts to establish clinical practice guidelines for dealing with impacted teeth. Data is beginning to accumulate from third molar studies, which hopefully will provide surgeons and their patients with evidence-based guidelines regarding elective third molar surgery.

  7. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Directory of Open Access Journals (Sweden)

    Bernardo Q Souki

    2015-01-01

    Full Text Available Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

  8. Analysis of the mineral composition of hypomineralized first permanent molars

    Directory of Open Access Journals (Sweden)

    Martinović Brankica

    2015-01-01

    Full Text Available Background/Aim. Hypomineralization of molars and incisors (molar-incisor hypomineralization - MIH is defined as enamel hypomineralization of systemic origin of one or more of the four first permanent molars, which may be associated with changes in the maxillary, and less frequently in the permanent mandibular incisors. The aim of this study was to investigate the mineral content in hypomineralized teeth as a contribution to under-standing the origin of these changes, which will be important for effective restorative approach. Methods. A total of 10 extracted first permanent molars diagnosed with MIH were used in the study as the experimental group, and intact first premolars extracted for orthodontic reasons were used as the control group. A certain surface of hypomineralized аnd healthy enamel and dentin was analyzed using a scanning electron microscope equipped with an energydispersive spectrometer (SEM/EDS. Results. By conducting quantitative chemical analysis of the distribution of the basic chemical elements, it was found that the concentration of calcium (Ca and phosphorus (P was significantly higher in healthy enamel (Ca = 28.80 wt%, and P = 15.05 wt% compared to hypomineralized enamel (Ca = 27.60 wt% and P = 14.32 wt%. Carbon (C concentration was statistically significantly higher in hypomineralized enamel (C = 11.70 wt% compared to healthy enamel (C = 10.94 wt%. Hypomineralized and healthy enamel did not differ significantly regarding the ratio of calcium and phosphorus concentrations whereas the ratio of calcium and carbon concentrations was statistically significantly higher in healthy enamel compared to hypomineralized enamel. Conclusion. Concentration of the main chemical elements, primarily calcium and phosphorus, is significantly reduced in hypomineralized enamel whereas carbon concentration is increased compared to healthy enamel.

  9. Structure and Properties of BiOl/TiO2 (A) Photocatalysts with Different Bi/Ti Molar Ratios%具有不同Bi/Ti摩尔比的BiO(l)/TiO2(A)光催化剂的结构与性能

    Institute of Scientific and Technical Information of China (English)

    李慧泉; 崔玉民; 吴兴才; 华林; 洪文珊

    2012-01-01

    BiOI-sensitized nano-anatase (TiO2 (A)) photocatalysts were prepared by a deposition method at room temperature,and characterized by X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),and photoluminescence (PL),and UV-Vis diffuse reflectance spectra (UV-Vis DRS).The photocatalytic activities were evaluated by photo-degradation experiments of rhodamine B.With increasing BiOl content,the absorption intensity of BiOl/TiO2 (A) increases in the 370-630 nm region and the absorption band edge redshifts.The UV and visible light photocatalytic activities increase,reaching a maximum when the Bi/Ti molar ratio is 1.7%.The 1.7% BiOl/TiO2 (A) catalyst exhibits much higher visible-light photoactivity than P25,and its UV-light photoactivity is slightly higher than that of P25.The UV and visible light photocatalytic activities of BiOl/TiO2 (A) with similar BiOl content are lower than those of BiOl/P25 catalysts.Compared with TiO2 (A),1.7% BiOl/TiO2 (A) shows higher UV and visible light photoactivities.This is attributed to the strong absorption in the 370-630 nm region,the redshift of the absorption band edge,and the effective transfer of the photogenerated electrons and holes,which reduces the recombination of electron-hole pairs.%在室温条件下通过沉积法制备了BiOl敏化纳米锐钛矿TiO2(A)光催化剂.用X射线衍射(XRD),X射线光电子能谱(XPS),光致发光(PL)光谱和紫外-可见漫反射光谱(UV-Vis DRS)等手段对其进行了表征.通过罗丹明B (RhB)催化降解实验评价了其光催化活性.随BiOl含量增加,BiOl/TiO2(A)在370-630 nm的吸收强度增强,吸收带边红移增加,紫外和可见光催化活性先增加,当Bi/Ti摩尔比约为1.7%时,各自达到最大值,然后随BiOl含量的进一步增加而减小.1.7% BiOl/TiO2(A)的可见光活性明显高于P25,它的紫外光活性也略高于P25.在BiOl含量相近时,BiOl/TiO2(A)比BiOl/P25具有更低的光催化活性,和TiO2(A)相比,1.7% BiOl/TiO2(A)明显

  10. Fusión de un tercer molar mandibular con un cuarto molar supernumerario Fusion of mandibular third molar with supernumerary fourth molar

    Directory of Open Access Journals (Sweden)

    C. López Carriches

    2008-10-01

    Full Text Available La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia del cordal semiincluido bajo anestesia local. Llevamos a cabo una revisión bibliográfica al respecto.Dental fusion is the union of two tooth buds that normally are separated, while gemination is defined as an attempt by a single tooth bud to divide. The fusion and gemination of molars is uncommon in permanent teeth. We report a clinical case of a right lower third molar fused to a supernumerary fourth molar in a 36-year-old male patient with repeated episodes of inflammation. After the radiologic study, the semi-impacted third molar was extracted under local anesthesia. The literature was reviewed.

  11. Sextant of Sapphires for Molar Distalization

    Science.gov (United States)

    Palla, Yudistar Venkata; Ganugapanta, Vivek Reddy

    2016-01-01

    Introduction Space analysis quantifies the amount of crowding within the arches estimating the severity of space discrepancy. The space gaining procedures include extraction and non-extraction procedures like expansion, proximal stripping and molar distalization. Aim To identify features seen in molar distalization cases. Materials and Methods The sample size comprised 20 patients in whom molar distalization was decided as the treatment plan. The study models and lateral cephalograms of all the patients were taken. Occlusograms were obtained. Model analysis and cephalometric analysis were performed. Descriptive statistical analysis like mean, standard deviation, standard error and mode were done. Results The parameters in Question gave following results. The Bolton analysis showed anterior mandibular excess with mean value of 1.56mm±1.07. The first order discrepancy between maxillary central and lateral incisors was 5±1.95. The premolar rotation showed mean value of 16.58±5.12. The molar rotation showed the value of 7.66±2.26. The nasolabial angle showed the mean of 101.25±8.7 IMPA of 101.4±5.74. Conclusion The six features studied in molar distalization cases [First order discrepancy between upper central and lateral incisors; Rotation of premolars and molars; Bolton’s discrepancy in anterior dentition; Average to horizontal growth pattern; Proclined lower incisors and Obtuse nasolabial angle] can be taken as patterns seen in molar distalization cases and considered as a valid treatment plan. PMID:27656572

  12. Role of third molars in orthodontics

    Science.gov (United States)

    Almpani, Konstantinia; Kolokitha, Olga-Elpis

    2015-01-01

    The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not been discussed at the same level is their involvement in orthodontic therapy. The aim of this study is to present a review of the contemporary literature regarding the most broadly discussed aspects of the multifactorial role of third molars in orthodontics and which are of general dental interest too. PMID:25685759

  13. Unilateral Molar Distalization: A Nonextraction Therapy

    Directory of Open Access Journals (Sweden)

    M. Bhanu Prasad

    2012-01-01

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

  14. Treatment of ectopic first permanent molar teeth.

    LENUS (Irish Health Repository)

    Hennessy, Joe

    2012-11-01

    Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. CLINICAL RELEVANCE: This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

  15. Method of Preparation for High-Purity Nanocrystalline Anhydrous Cesium Perrhenate

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-03-01

    Full Text Available This paper is devoted to the preparation of high-purity anhydrous nanocrystalline cesium perrhenate, which is applied in catalyst preparation. It was found that anhydrous cesium perrhenate with a crystal size <45 nm can be obtained using cesium ion sorption and elution using aqueous solutions of perrhenic acid with subsequent crystallisation, purification, and drying. The following composition of the as-obtained product was reported: 34.7% Cs; 48.6% Re and <2 ppm Bi; <3 ppm Zn; <2 ppm As; <10 ppm Ni; < 3 ppm Mg; <5 ppm Cu; <5 ppm Mo; <5 ppm Pb; <10 ppm K; <2 ppm Na; <5 ppm Ca; <3 ppm Fe.

  16. Ab initio and DFT studies of the structure and vibrational spectra of anhydrous caffeine.

    Science.gov (United States)

    Srivastava, Santosh K; Singh, Vipin B

    2013-11-01

    Vibrational spectra and molecular structure of anhydrous caffeine have been systematically investigated by second order Moller-Plesset (MP2) perturbation theory and density functional theory (DFT) calculations. Vibrational assignments have been made and many previous ambiguous assignments in IR and Raman spectra are amended. The calculated DFT frequencies and intensities at B3LYP/6-311++G(2d,2p) level, were found to be in better agreement with the experimental values. It was found that DFT with B3LYP functional predicts harmonic vibrational wave numbers more close to experimentally observed value when it was performed on MP2 optimized geometry rather than DFT geometry. The calculated TD-DFT vertical excitation electronic energies of the valence excited states of anhydrous caffeine are found to be in consonance to the experimental absorption peaks.

  17. Ab initio and DFT studies of the structure and vibrational spectra of anhydrous caffeine

    Science.gov (United States)

    Srivastava, Santosh K.; Singh, Vipin B.

    2013-11-01

    Vibrational spectra and molecular structure of anhydrous caffeine have been systematically investigated by second order Moller-Plesset (MP2) perturbation theory and density functional theory (DFT) calculations. Vibrational assignments have been made and many previous ambiguous assignments in IR and Raman spectra are amended. The calculated DFT frequencies and intensities at B3LYP/6-311++G(2d,2p) level, were found to be in better agreement with the experimental values. It was found that DFT with B3LYP functional predicts harmonic vibrational wave numbers more close to experimentally observed value when it was performed on MP2 optimized geometry rather than DFT geometry. The calculated TD-DFT vertical excitation electronic energies of the valence excited states of anhydrous caffeine are found to be in consonance to the experimental absorption peaks.

  18. A Molar Pregnancy within the Fallopian Tube

    Directory of Open Access Journals (Sweden)

    Laura Allen

    2016-01-01

    Full Text Available Background. Discussion of the incidence of molar pregnancy and ectopic pregnancy. Role of salpingostomy and special considerations for postoperative care. Case. The patient is a 29-year-old G7P4 who presented with vaginal bleeding in the first trimester and was initially thought to have a spontaneous abortion. Ultrasound was performed due to ongoing symptoms and an adnexal mass was noted. She underwent uncomplicated salpingostomy and was later found to have a partial molar ectopic pregnancy. Conclusion. This case illustrates the rare occurrence of a molar ectopic pregnancy. There was no indication of molar pregnancy preoperatively and this case highlights the importance of submitting and reviewing pathological specimens.

  19. Dental Interventions on First Permanent Molars

    OpenAIRE

    2016-01-01

    The first permanent molars have the biggest dental morbidity and mortality of all permanent teeth. The main aim was to evaluate of the most common dental problems and procedures that are performed on the first permanent molars. Material and method: examination was performed in three private dental offices, two from urban and one from rural region, over a period of 2 years. The data was obtained by using dental charts from the patients and by the ambulatory register for performe...

  20. Single-rooted primary first mandibular molar

    OpenAIRE

    Haridoss, SelvaKumar; Swaminathan, Kavitha; Rajendran, Vijayakumar; Rajendran, Bharathan

    2014-01-01

    Morphological variations like single-rooted molar in primary dentition are scarce. Understanding the root canal anatomy and variations is necessary for successful root canal therapy. The purpose of the present article is to report successful endodontic treatment of primary left mandibular first molar with an abnormal morphology of a single root. This case report highlights the importance of knowledge and its applications in the management of anomalous anatomic variants which play a crucial ro...

  1. The life quality after third molar surgery

    OpenAIRE

    Dimova, Cena

    2010-01-01

    Aim: The aims of this retrospective study were: first of all, to evaluate the patients’ perception of changes in oral health–related quality of life over a 2-month period after third molar surgery. Second aim was to compare the clinical outcome of performed oral surgery with evaluation the influence of factors affecting outcome. Material and Methods. A total of 30 consecutive healthy patients who presented with unilaterally or bilaterally impacted mandible third molar were included in this...

  2. Clinical management of the mandibular molars.

    Science.gov (United States)

    Canut, J A

    1975-09-01

    The complex variety of clinical problems posed by the lower molars requires maximum care in diagnosis and in treatment planning. In this article several therapeutic solutions to these problems are presented. The need to treat positional anomalies of the second molars and to control their drifting in cases of bracing and mandibular insertion, may be an effective auxillary means of treatment of those malocclusions in which lengthening of the dental bracing zones is indicated.

  3. Molar Incisor Hypomineralization, Prevalence, and Etiology

    OpenAIRE

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

    2014-01-01

    Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data wer...

  4. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-11-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2‧-(2,6-pyridine)-5,5‧-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm‑2 for both anode and cathode sides showed a power density of 76 mW cm‑2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm‑2 with 0.45 mgPt cm‑2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm‑2 in cathode and 0.05 mgPd cm‑2 in anode reached 188 mW cm‑2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs.

  5. Mössbauer study on the gamma radiolysis of anhydrous cesium tris (oxalato) ferrate(III)

    Science.gov (United States)

    Ladriere, J.; Senterre, V.; Apers, D.

    1992-04-01

    The final product of the gamma radiolysis of anhydrous cesium tris(oxalato) ferrate(III) has been identified by Mössbauer spectroscopy as Cs2Fe(ox)2. The radiolytic decomposition proceeds as a first-order process due to the original compound depletion and to the radiolytic stability of the ferrous compound. Lamb-Mössbauer factors measurements indicate that the recoilless fractions of the iron species are practically unaffected by the radiolysis.

  6. Neutron diffraction analysis of residual stresses near unannealed welds in anhydrous ammonia nurse tanks.

    Science.gov (United States)

    Becker, A T; Chumbley, L S; Goettee, D; Russell, A M

    2014-01-01

    Neutron diffraction analysis was employed to measure residual stresses near welds in used anhydrous ammonia nurse tanks. Tensile residual stresses contribute to stress corrosion cracking of nurse tanks, which can cause tanks to release toxic ammonia vapor. The analysis showed that tensile residual stresses were present in the tanks measured, and the magnitudes of these stresses approached the yield strength of the steel. Implications for agricultural safety and health are discussed.

  7. THE PRODUCTION OF PURE ABSOLUTE ALCOHOL WITH CALCIUM CARBIDE AND ANHYDROUS COPPER SULPHATE.

    Science.gov (United States)

    Lyons, R E; Smith, L T

    1925-09-01

    (1) The above is recommended as an economical, convenient and quick method for producing absolute alcohol on a laboratory scale. If the distillation is executed with free flame, excessive or careless heating must be avoided near the end of the operation because of the copper acetylide in the residue. (2) Calcium carbide is recommended over potassium permanganate or anhydrous copper sulphate as a qualitative reagent in detecting traces of water in alcohol.

  8. Use of lycopene as a natural antioxidant in extending the shelf-life of anhydrous cow milk fat.

    Science.gov (United States)

    Siwach, Ruby; Tokas, Jayanti; Seth, Raman

    2016-05-15

    Oxidative rancidity in anhydrous cow milk fat leads to reduction in its shelf life. Use of synthetic antioxidants is prevalent in dairy industry to prevent the development of rancidity. Keeping in view the increasing demand for natural additives, the present study was carried out to explore the potential of lycopene as a natural antioxidant in anhydrous cow milk fat. Lycopene at five different levels (30, 60, 90, 120 and 150 ppm) and butylated hydroxyl anisole (200 ppm), were incorporated in anhydrous cow milk fat. Potential of lycopene extract to enhance the shelf life of anhydrous cow milk fat was evaluated by measuring Free Fatty Acids, peroxide value, Thiobarbituric Acid value and color value during 12 months of storage at ambient conditions (30°C). Lycopene significantly (pLycopene containing samples scored significantly higher in terms of sensory attributes as compared to control.

  9. Influence of deciduous molar hypomineralization on the development of molar-incisor hypomineralizarion

    OpenAIRE

    Costa-Silva C.M.; Paula J.S.; Ambrosano G.M.B.; Mialhe F.L.

    2013-01-01

    Defects similar to Molar-Incisor Hypomineralization (MIH) in second primary molars can be found in the literature, being recently named Deciduous Molar Hypomineralization (DMH). Researchers have stated that the presence of DMH in primary dentition represents a risk for MIH in permanent teeth. The explanation for this association is probably related to the etiological factors. Aim: To investigate prospectively the association between DMH and MIH and the etiologic factors involved in both defec...

  10. Influence of treatment including second molars on final and postretention molar angulation

    Directory of Open Access Journals (Sweden)

    Luiz Filiphe Gonçalves Canuto

    2013-10-01

    Full Text Available OBJECTIVE: Evaluate axial mesiodistal inclinations of the mandibular molars in orthodontically treated cases, analyzing whether inclusion of second mandibular molars in treatment mechanics has any influence on final and postretention molars angulations. METHODS: The sample comprised 150 panoramic radiographs of 50 patients. Patients were treated with extraction of four first premolars and divided into 2 groups: Group 1 comprised 25 subjects without inclusion of mandibular second molars during orthodontic treatment, whereas Group 2 comprised 25 subjects with inclusion of mandibular second molars. Panoramic radiographs at three observation times were evaluated: pretreatment, posttreatment and postretention. The statistical analysis included one-way analysis of variance (ANOVA for intragroup evaluation and independent t-tests for intergroup comparisons. RESULTS: Intragroup analysis demonstrated significant uprighting of mandibular first and second molars during treatment in Group 2, which remained stable during the postretention stage. Intergroup comparison demonstrated that Group 2 presented first and second molars significantly more uprighted in relation to Group 1 in both post-treatment and postretention stages. CONCLUSIONS: It was concluded that inclusion of mandibular second molars in the orthodontic mechanics is relevant not only to correct the angulation of these teeth, but also to aid mandibular first molars uprighting.

  11. Ankylosis of primary molar along with congenitally missing first permanent molar

    Directory of Open Access Journals (Sweden)

    Suprabha B

    2006-05-01

    Full Text Available Ankylosis of primary mandibular molars has been routinely found to be associated with various developmental disturbances in permanent dentition such as aplasia of the succedaneous tooth, ectopic eruption of the premolar, infraoclusion of the ankylosed tooth leading to tipping of the first permanent molar etc. This article describes a rare case where there was ankylosis of a mandibular second primary molar along with congenitally missing first permanent molar which resulted in the transposition of second premolar. Treatment options and prognosis of the case are discussed.

  12. Lipase-catalyzed process in an anhydrous medium with enzyme reutilization to produce biodiesel with low acid value.

    Science.gov (United States)

    Azócar, Laura; Ciudad, Gustavo; Heipieper, Hermann J; Muñoz, Robinson; Navia, Rodrigo

    2011-12-01

    One major problem in the lipase-catalyzed production of biodiesel or fatty acid methyl esters (FAME) is the high acidity of the product, mainly caused by water presence, which produces parallel hydrolysis and esterification reactions instead of transesterification to FAME. Therefore, the use of reaction medium in absence of water (anhydrous medium) was investigated in a lipase-catalyzed process to improve FAME yield and final product quality. FAME production catalyzed by Novozym 435 was carried out using waste frying oil (WFO) as raw material, methanol as acyl acceptor, and 3Å molecular sieves to extract the water. The anhydrous conditions allowed the esterification of free fatty acids (FFA) from feedstock at the initial reaction time. However, after the initial esterification process, water absence avoided the consecutives reactions of hydrolysis and esterification, producing FAME mainly by transesterification. Using this anhydrous medium, a decreasing in both the acid value and the diglycerides content in the product were observed, simultaneously improving FAME yield. Enzyme reuse in the anhydrous medium was also studied. The use of the moderate polar solvent tert-butanol as a co-solvent led to a stable catalysis using Novozym 435 even after 17 successive cycles of FAME production under anhydrous conditions. These results indicate that a lipase-catalyzed process in an anhydrous medium coupled with enzyme reuse would be suitable for biodiesel production, promoting the use of oils of different origin as raw materials.

  13. Chemical and mineralogical size segregation in the impact disruption of anhydrous stone meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, G.J.; Durda, D.D. (SUNYP); (SW Research Institute)

    2005-02-02

    We performed impact disruption experiments on pieces from eight different anhydrous chondritic meteorites - four weathered ordinary chondrite finds from North Africa (NWA791, NWA620, NWA869 and MOR001), three almost unweathered ordinary chondrite falls (Mbale, Gao, and Saratov), and an almost unweathered carbonaceous chondrite fall (Allende). In each case the impactor was a small (1/8 or 1/4 in) aluminum sphere fired at the meteorite target at {approx} 5 km/s, comparable to the mean collision speed in the main-belt. Some of the {approx}5 to {approx} 150 {micro}m debris from each disruption was collected in aerogel capture cells, and the captured particles were analyzed by in situ synchrotron-based X-ray fluorescence. For each meteorite, many of the smallest particles (< 10 {micro}m up to 35 {micro}m in size, depending on the meteorite) exhibit very high Ni/Fe ratios compared to the Ni/Fe ratios measured in the larger particles (> 45 {micro}m), a composition consistent with the smallest debris being dominated by matrix material while the larger debris is dominated by fragments from olivine chondrules. These results may explain why the {approx} 10 {micro}m interplanetary dust particles (IDPs) collected from the Earth's stratosphere are C-rich and volatile-rich compared to the presumed solar nebula composition. The {approx} 10 {micro}m IDPs may simply sample the matrix of an inhomogeneous parent body, structurally and mineralogically similar to the chondritic meteorites, which are inhomogeneous assemblages of compact, strong, C- and volatile-poor chondrules that are distributed in a more porous, C- and volatile-rich matrix. In addition, these results may explain why the micrometeorites, which are {approx} 50 {micro}m to millimeters in size, recovered from the polar ices are Ni- and S-poor compared to chondritic meteorites, since these polar micrometeorites may preferentially sample fragments from the Ni- and S-poor olivine chondrules. These results indicate that

  14. Comparing Eruption Space of the Lower Third Molar in Unerupted and Erupted Teeth via Digital Anoramic Radiography in Patients Referring to Yazd Dental College during 2011-13

    Directory of Open Access Journals (Sweden)

    F Ezoddini Ardakani

    2014-08-01

    Full Text Available Introduction: The aim of this study is to determine and compare the eruption space of unerupted and erupted third molars by the means of digital panoramic radiography in patients referring to Yazd dental college during 2011-2013. Methods: In this cross-sectional descriptive study, 150 archived digital panoramic radiographies in radiology department were evaluated with Romexis software under the standard circumstances. The radiographic pictures belonged to 73 men and 77 women with the average age of 21.18±1.67 years. In patients with erupted third molars as well as unerupted third molars (mesio-angular and vertical, several parameters were examined including: angle of the tooth axis of second and third molar, Gonial angle, the width of third molar, retro-molar space and its ratio to the width of third molar, the development stage of third molar root as well as the distance between the center of ramus and the most distal point of second molar. The data related to age, sex and the eruption situation of lower third molar- unerupted or erupted- were extracted from the patient’s log. The data were analyzed by SPSS (ver.17 via applying descriptive tests and T-test. Results: A statistically significant difference was observed between the two groups in regard with the average angle between second and third molar, the mean space of retro-molar and its ratio to the width of third molar as well as the mean distance between centers of ramus and second molar (P=0.0001. Moreover, no significant difference was observed in Gonial angle mean (P=0.213 and the width of third molar (P.value=0.348. Conclusion: Increasing the angle between second and third molar as well as inadequate space of retro-molar can lead to impaction of lower third molar, but the width of third molar and the Gonial angle size did not reveal any significant role in determination of impaction or eruption of third molar.

  15. Does fixed retention prevent overeruption of unopposed mandibular second molars in maxillary first molar extraction cases?

    NARCIS (Netherlands)

    Livas, Christos; Halazonetis, Demetrios J; Booij, Johan W; Katsaros, Christos; Ren, Yijin

    2016-01-01

    BACKGROUND: The objective of this study was to investigate whether multistranded fixed retainers prevented overeruption of unopposed mandibular second molars in maxillary first molar extraction cases. METHODS: The panoramic radiographs of 65 Class II Division 1 Caucasian Whites (28 females, 37 males

  16. Molar heat capacity and molar excess enthalpy measurements in aqueous amine solutions

    Science.gov (United States)

    Poozesh, Saeed

    Experimental measurements of molar heat capacity and molar excess enthalpy for 1, 4-dimethyl piperazine (1, 4-DMPZ), 1-(2-hydroxyethyl) piperazine (1, 2-HEPZ), I-methyl piperazine (1-MPZ), 3-morpholinopropyl amine (3-MOPA), and 4-(2-hydroxy ethyl) morpholine (4, 2-HEMO) aqueous solutions were carried out in a C80 heat flow calorimeter over a range of temperatures from (298.15 to 353.15) K and for the entire range of the mole fractions. The estimated uncertainty in the measured values of the molar heat capacity and molar excess enthalpy was found to be +/- 2%. Among the five amines studied, 3-MOPA had the highest values of the molar heat capacity and 1-MPZ the lowest. Values of molar heat capacities of amines were dominated by --CH 2, --N, --OH, --O, --NH2 groups and increased with increasing temperature, and contributions of --NH and --CH 3 groups decreased with increasing temperature for these cyclic amines. Molar excess heat capacities were calculated from the measured molar heat capacities and were correlated as a function of the mole fractions employing the Redlich-Kister equation. The molar excess enthalpy values were also correlated as a function of the mole fractions employing the Redlich-Kister equation. Molar enthalpies at infinite dilution were derived. Molar excess enthalpy values were modeled using the solution theory models: NRTL (Non Random Two Liquid) and UNIQUAC (UNIversal QUAsi Chemical) and the modified UNIFAC (UNIversal quasi chemical Functional group Activity Coefficients - Dortmund). The modified UNIFAC was found to be the most accurate and reliable model for the representation and prediction of the molar excess enthalpy values. Among the five amines, the 1-MPZ + water system exhibited the highest values of molar excess enthalpy on the negative side. This study confirmed the conclusion made by Maham et al. (71) that -CH3 group contributed to higher molar excess enthalpies. The negative excess enthalpies were reduced due to the contribution of

  17. 无水乙醇预处理提取番茄红素工艺优化%Optimization of Pretreatment Process with Anhydrous EthanoI for Lycopene Extraction

    Institute of Scientific and Technical Information of China (English)

    范少丽; 敬思群; 纵伟

    2015-01-01

    Lycopene is extracted by anhydrous ethanol pretreatment method with ethyl acetate as extraction solvent and lycopene extraction rate as index.The optimal conditions of anhydrous ethanol pretreatment are obtained through single factor and orthogonal experiments,and the results show that the anhydrous ethanol pretreatment processing time is of 20 min,the processing temperature of 50 ℃, and the solid-liquid ratio of 1 ∶ 2,the number of processing stage is 2.Under these conditions, lycopene extraction rate is up to 62.45 mg/100 g and lycopene content reaches 80.69%.The modern instrumental analysis methods such as SEM,IR and XRD are applied to characterize the product,and the results show that the characterization of lycopene product and pretreatment of anhydrous ethanol is basically in accordance with the lycopene standard.%采用无水乙醇预处理番茄酱,用乙酸乙酯提取番茄红素,以番茄红素提取得率为考察指标,通过单因素和正交实验确定无水乙醇预处理最优条件为:预处理时间20 min、处理温度50℃、料液比1∶2、二级处理,番茄红素提取得率为62.45 mg/100 g,番茄红素含量可达80.69%。同时采用 SEM,IR,XRD现代仪器分析手段对番茄红素产品进行表征,结果表明无水乙醇预处理提取得到番茄红素产品表征与番茄红素标准品基本一致。

  18. Fusión de un tercer molar mandibular con un cuarto molar supernumerario Fusion of mandibular third molar with supernumerary fourth molar

    OpenAIRE

    C. López Carriches; I. Leco Berrocal; R. Baca Pérez-Bryan

    2008-01-01

    La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia...

  19. Diagnosis and treatment of molar incisor hypomineralization.

    Science.gov (United States)

    Mathu-Muju, Kavita; Wright, J Timothy

    2006-11-01

    Molar incisor hypomineralization (MIH) is a relatively common condition that varies in clinical severity and can result in early loss of the permanent 6-year molars. The etiology of MIH remains unclear, and the diagnosis can be confused with more generalized enamel defects such as those that occur in amelogenesis imperfecta. The management of MIH depends largely on the severity of the enamel defect. Degrees of hypomineralization can range from mild enamel opacities to enamel that readily abrades from the tooth as it emerges into the oral cavity. Usually, severely affected molars are extremely hypersensitive, prone to rapid caries development, and can be difficult to manage in young patients. The purpose of this article is to review approaches to diagnosing and treating MIH.

  20. Molar tubal ectopic pregnancy: Report of two cases.

    Science.gov (United States)

    Mbarki, Chaouki; Jerbi, Emna; Hsayaoui, Najeh; Zouari, Fatma; Ben Brahim, Ehsen; Oueslati, Hedhili

    2015-06-01

    Ectopic molar pregnancy is a rare occurrence and consequently not often considered as a diagnostic possibility. We report two cases of molar hydatidiform tubal pregnancy. Diagnosis of ectopic pregnancy was confirmed on clinical biological and sonographic investigations. Diagnosis of molar pregnancy was done on histopathology. The clinical course was favorable for both patients. Although rare, molar changes can occur at any site of an ectopic pregnancy. Clinical diagnosis of a molar pregnancy is difficult but histopathology is the gold standard for diagnosis.

  1. Bone resorption in incompletely impacted mandibular third molars and acute pericoronitis

    Directory of Open Access Journals (Sweden)

    Minoru Yamaoka

    2009-04-01

    Full Text Available Minoru Yamaoka, Yusuke Ono, Masahiro Takahashi, Ryosuke Doto, Kouichi Yasuda, Takashi Uematsu, Kiyofumi FurusawaMatsumoto Dental University, School of Dentistry, Shiojiri, Nagano, JapanAbstract: Acute pericoronitis (AP arises frequently in incompletely impacted mandibular third molars, but it remains unknown whether bone resorption in aging is associated with acute inflammation of the third molar. We conducted an experiment to compare the ratio of bone resorption to root length in the distal surface of the second molar (A, the proximal surface (B, and distal surface (C in mesio-angular, incompletely impacted third molars in 27 young and 58 older adults with AP and 77 young and 79 older adults without a history of AP. Bone resorption in A, B, and C in older adults with AP demonstrated a significantly higher ratio when compared to those without AP, whereas there was no difference between those with and without AP in young adults except for B in women. However, there were no differences between bone resorption in B with AP in young and older women, and between bone resorption in C with AP in young and older adults. These indicate that AP and bone resorption are associated with incompletely impacted mandibular third molars in older adults.Keywords: bone resorption, pericoronitis, mandible, acute inflammation, elderly

  2. Bone resorption in incompletely impacted mandibular third molars and acute pericoronitis.

    Science.gov (United States)

    Yamaoka, Minoru; Ono, Yusuke; Takahashi, Masahiro; Doto, Ryosuke; Yasuda, Kouichi; Uematsu, Takashi; Furusawa, Kiyofumi

    2009-01-01

    Acute pericoronitis (AP) arises frequently in incompletely impacted mandibular third molars, but it remains unknown whether bone resorption in aging is associated with acute inflammation of the third molar. We conducted an experiment to compare the ratio of bone resorption to root length in the distal surface of the second molar (A), the proximal surface (B), and distal surface (C) in mesio-angular, incompletely impacted third molars in 27 young and 58 older adults with AP and 77 young and 79 older adults without a history of AP. Bone resorption in A, B, and C in older adults with AP demonstrated a significantly higher ratio when compared to those without AP, whereas there was no difference between those with and without AP in young adults except for B in women. However, there were no differences between bone resorption in B with AP in young and older women, and between bone resorption in C with AP in young and older adults. These indicate that AP and bone resorption are associated with incompletely impacted mandibular third molars in older adults.

  3. Distalización de molares

    Directory of Open Access Journals (Sweden)

    Ana María García Jiménez

    2016-01-01

    Full Text Available La distoclusión es una anomalía que alcanza a más de la mitad de los pacientes ortodóncicos, entre sus causas se encuentra la mesogresión de molares superiores. Una opción terapéutica es la distalización molar, cuando se considera la corrección sin extracciones. Se presenta el caso de un paciente remitido desde la atención primaria de salud, con relación molar de distoclusión derecha, neutroclusion izquierda, resalte de seis milímetros y sobrepase corona completa. Previa confección de modelos de estudio e indicación de estudio radiográfico, se procedió a la corrección ortodóncica con la placa Cetlin, a la que se le realizaron algunas modificaciones. Se corrigió la distoclusión del primer molar permanente superior derecho hasta la neutroclusión; además del espacio requerido para el acomodamiento del canino superior derecho, se logró la corrección del sobrepase hasta un tercio de corona y se mejoró el resalte de seis a cuatro milímetros.

  4. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

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

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement...

  5. Survival analysis of banding and bonding molar tubes in adult patients over a 12-month period: a split-mouth randomized clinical trial.

    Science.gov (United States)

    Oeiras, Valéria Jacques; Silva, Valéria Assis Almeida E; Azevedo, Leidiana Aguiar; Lobato, Vanessa Soares; Normando, David

    2016-12-22

    This split-mouth randomized clinical trial aimed to compare the survival rate of bonding and banding molar tubes in adult orthodontic patients. Eligibility criteria included adults (aged >18 years), no active caries, restorations, or fractures in the upper and lower molars. The main outcome was any type of first-time failure in molar tubes. A computer-generated randomization scheme was used in a 1:1 ratio. The survival rate was estimated for 32 adult patients, in whom a tube was bonded to a molar tooth using composite resin on one side and a band was cemented with glass ionomer onto the same tooth in the contralateral arch. A total of 59 banded and 59 bonded molars were followed up for 12 months. Blinding was not applicable. Survival analysis including Cox regression was used at p < 0.05. The survival rate of bonded molars was not statistically different from that of banded molars (log-rank test, p = 0.97). Hazard ratio (HR) was 0.72 (95%CI, 0.38-1.31). Bonded upper molars yielded a survival rate of 81.25% (26 out of 32) compared to 71.87% (23 out of 32) for banded upper molars. The survival rate was 66.66% (18 out of 27) for banded lower molars and 59.25% for bonded lower molars (16 out of 27). The HR for lower vs. upper arch was 2.16 (95%CI, 1.18-3.98). No serious problem was observed other than gingivitis associated with plaque accumulation. In contrast to previous studies in young patients, in adults, bonding orthodontic tubes to molars is similar to molar banding. However, both procedures had a high failure rate in the lower arch.

  6. A kinetic study of non-isothermal decomposition process of anhydrous nickel nitrate under air atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Jankovic, B., E-mail: bojanjan@ffh.bg.ac.r [Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, P. O. Box 137, 11001 Belgrade (Serbia); Mentus, S. [Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, P. O. Box 137, 11001 Belgrade (Serbia); Jelic, D. [Faculty of Medicine, University of Banja Luka, 78000 Banja Luka (Bosnia and Herzegowina)

    2009-08-01

    The non-isothermal decomposition process of anhydrous nickel nitrate under air atmosphere was investigated. The kinetic analysis of decomposition process was performed using Friedman (FR), Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) isoconversional methods. The kinetic model was determined by the Malek's method. The composite differential method I was used for checking the established reaction model. It was found that the value of E{sub a} calculated by composite differential method (E{sub a}=147.1 kJ mol{sup -1}) represents the medium value between the values of the apparent activation energy calculated by FR (E{sub a,FR}=152.8 kJ mol{sup -1}) and FWO (E{sub a,FWO}=143.1 kJ mol{sup -1}) methods. Using two special functions (y(alpha) and z(alpha)), it was found that the two-parameter autocatalytic model (Sestak-Berggren (SB) kinetic model) with kinetic exponents M=0.23 and N=1.14 is the most adequate one to describe the decomposition kinetics of the studied system at various heating rates. The obtained non-isothermal differential conversion curves from the experimental data show the results being accordant with those theoretically calculated. It was concluded that the SB kinetic model can be used for a quantitative description of non-isothermal decomposition process of anhydrous nickel nitrate which involves the partially overlapping nucleation and growth phases.

  7. Anhydrous proton conducting materials based on sulfonated dimethylphenethylchlorosilane grafted mesoporous silica/ionic liquid composite.

    Science.gov (United States)

    Amiinu, Ibrahim Saana; Liang, Xinmiao; Tu, Zhengkai; Zhang, Haining; Feng, Jiwen; Wan, Zhongmin; Pan, Mu

    2013-11-27

    Efficient membrane proton conductivity at elevated temperatures (>100 °C) and reduced humidification conditions is a critical issue hindering fuel cell commercialization. Herein, proton conducting materials consisting of high surface area acid catalyzed mesoporous silica functionalized with sulfonated dimethylphenethylchlorosilane was investigated under anhydrous conditions. The organic moiety covalently bonded to the silica substrate via active hydroxyl groups on the silica pore surface. The structure and dynamic phases of the attached organic molecule were characterized and qualitatively determined by XRD, TEM, FT-IR, and solid state NMR. The amount of grafted organic molecules was estimated to be 2.45 μmol m(-2) by carbon elemental analysis. The so-formed composite materials showed adequate thermal stability up to 300 °C as determined by TGA. Under anhydrous conditions, ionic conductivity of the composite material upon ionic liquid impregnation reaches a peak value of 1.14 × 10(-2) S cm(-1) at 160 °C associated with the activation energy of 9.24 kJ mol(-1) for proton transport.

  8. Anhydrous ethanol production in sugar mills; Produccion de etanol anhidro en ingenios azucareros

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez Poy, Manuel. E-mail:poymanuel@prodigy.net.mx

    2007-04-15

    The anhydrous ethanol production is recent and limited, because the disadvantage of the renewable energies is the economic impossibility of the projects. Nevertheless, there are aspects to consider to achieve the anhydrous ethanol production, among which are: the cost of the raw material, the self-sufficiency of energy from the sugar cane bagasse without the need of oil burning, the larger size of the distilleries, incorporation of the Cogeneration with delivery of electricity to the public network in the sugar mill facilities, the introduction of the biotechnology to improve the processes of fermentation and subsidies to agriculture. [Spanish] La produccion de etanol anhidro es reciente y limitada, debido a que la desventaja de las energias renovables es la inviabilidad economica de los proyectos. Sin embargo hay aspectos a considerar para lograr la produccion de etanol anhidro, entre los cuales estan: el costo de la materia prima, la autosuficiencia energetica a partir del bagazo de la cana sin necesidad de petroleo, mayor tamano de las destilerias, incorporacion de la Cogeneracion con entrega de electricidad a la red publica en el ingenio, la introduccion de la biotecnologia para mejorar los procesos de fermentacion y subsidios a la agricultura.

  9. Polyelectrolyte microcapsules as ionic liquid reservoirs within ionomer membrane to confer high anhydrous proton conductivity

    Science.gov (United States)

    Zhang, Haoqin; Wu, Wenjia; Li, Yifan; Liu, Yong; Wang, Jingtao; Zhang, Bing; Liu, Jindun

    2015-04-01

    Herein, novel composite membranes are prepared by embedding methacrylic acid polyelectrolyte microcapsules (PMCs) into sulfonated poly(ether ether ketone) (SPEEK) matrix, followed by impregnating imidazole-type ionic liquids (ILs). Within the composite membrane, the lumens of PMCs act as IL reservoirs, which provide large space for IL storage and thus significantly elevate the IL uptake. The IL leaching measurement suggests that the cross-linked shells of PMCs manipulate the IL release, endowing the composite membrane with high IL retention. Moreover, the high IL retention renders the composite membrane more anhydrous hopping sites (e.g., the imidazole groups on IL and the acid-base pairs between imidazole and sulfonic acid groups), imparting a facilitated proton conduction via Grotthuss mechanism. In particular, the composite membrane containing 12% PMCs achieves a high anhydrous proton conductivity of 33.7 mS cm-1 at 150 °C. The same membrane also exhibits a surprising steady-state IL retention of 36.9% after leaching in liquid water.

  10. Incidence of distal caries in mandibular second molars due to impacted third molars: Nonintervention strategy of asymptomatic third molars causes harm? A retrospective study

    Science.gov (United States)

    Srivastava, Nikhil; Shetty, Akshay; Goswami, Rahul Dev; Apparaju, Vijay; Bagga, Vivek; Kale, Saurabh

    2017-01-01

    Background: Removal of impacted third molars is the most common oral surgical procedure. Many investigators have questioned the necessity of removal in patients who are free of symptoms or associated pathologies. Aim: The aim of this retrospective study was to evaluate the incidence of caries on distal aspect of mandibular second molars in patients referred for corresponding third molar assessment and to identify its association with angular position and depth of the impacted mandibular third molars based on the classification of Pell and Gregory. Methodology: Records of 150 patients with impacted third molar presenting to the Department of Oral and Maxillofacial Surgery, Sri Rajiv Gandhi College of Dental Sciences and Hospital, were assessed retrospectively. The radiographic angulation and depth of mandibular third molar impaction were determined and compared to determine the relationship with incidence of caries on the distal surface of the second molar. Results: According to this study results, 37.5% cases show caries on the distal aspect of mandibular second molars. The incidence of caries with mesioangular impacted third molars was 55%. A majority of these mesioangular cases were Level B and Class I as per the Pell and Gregory classification. Conclusion: The prophylactic extraction of mandibular third molars is indicated if the angulation is between 30° and 70° and is justified by incidence of distal caries in the second molars. PMID:28251102

  11. Structural characterization of anhydrous naloxone- and naltrexone hydrochloride by high resolution laboratory X-ray powder diffraction and thermal analysis.

    Science.gov (United States)

    Sugimoto, Kunihisa; Dinnebier, Robert E; Zakrzewski, Marek

    2007-12-01

    The crystal structures of the analgesic compounds anhydrous naloxone and naltrexone hydrochloride were determined ab initio from high resolution laboratory X-ray powder diffraction data. Both compounds crystallize in the orthorhombic space group P2(1)2(1)2(1) with lattice parameters of a = 14.6588(10) A, b = 17.4363(9) A, c = 7.96200(22) A, and V = 2035.06(23) A(3) for naloxone hydrochloride and a = 15.4560(5) A, b = 14.9809(4) A, c = 7.84121(18) A, and V = 1815.58(11) A(3) for naltrexone hydrochloride. The crystal structure of anhydrous naloxone hydrochloride forms one-dimensional chains through hydrogen bonds. In the crystal structure of anhydrous naltrexone hydrochloride, two-dimensional sheets are formed by hydrogen bonds. The dehydration processes of naloxone hydrochloride dehydrate and naltrexone hydrochloride tetrahydrate was analyzed by DTA, DSC, TG, and MG.

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

    Science.gov (United States)

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

    2012-11-01

    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.

  13. An innovative technique to distalize maxillary molar using microimplant supported rapid molar distalizer

    Directory of Open Access Journals (Sweden)

    Meenu Goel

    2013-01-01

    Full Text Available Introduction: In recent years, enhancements in implants have made their use possible as a mode of absolute anchorage in orthodontic patients. In this paper, the authors have introduced an innovative technique to unilaterally distalize the upper left 1 st molar to obtain an ideal Class I molar relationship from a Class II existing molar relationship with an indigenous designed distalizer. Clinical Innovation: For effective unilateral diatalization of molar, a novel cantilever sliding jig assembly was utilized with coil spring supported by a buccally placed single micro implant. The results showed 3 mm of bodily distalization with 1 mm of intrusion and 2° of distal tipping of upper left 1 st molar in 1.5 months. Discussion: This appliance is relatively easy to insert, well-tolerated, and requires minimal patient cooperation compared to other present techniques of molar distalization. Moreover, it is particularly useful in cases that are Class II on one side and Class I on the other, with a minor midline discrepancy and nominal overjet. Patient acceptance level was reported to be within patients physiological and comfort limits.

  14. Removal of Deeply Impacted Mandibular Molars by Sagittal Split Osteotomy

    Directory of Open Access Journals (Sweden)

    Erol Cansiz

    2016-01-01

    Full Text Available Mandibular third molars are the most common impacted teeth. Mandibular first and second molars do not share the same frequency of occurrence. In rare cases the occlusal surfaces of impacted molars are united by the same follicular space and the roots pointing in opposite direction; these are called kissing molars. In some cases, a supernumerary fourth molar can be seen as unerupted and, in this case, such a supernumerary, deeply impacted fourth molar is seen neighboring kissing molars. The extraction of deeply impacted wisdom molars from the mandible may necessitate excessive bone removal and it causes complications such as damage to the inferior alveolar nerve and iatrogenic fractures of the mandible. This case report describes the use of the sagittal split osteotomy technique to avoid extensive bone removal and protect the inferior alveolar nerve during surgical extruction of multiple impacted teeth.

  15. Intra-sinusal third molar: Case report

    Directory of Open Access Journals (Sweden)

    Frederico Sampaio Neves

    2011-01-01

    Full Text Available Ectopic tooth eruption into an area other than the oral cavity is rare. Nasal septum, mandibular condyle, coronoid process and infratemporal fossa space have been reported as frequent locations for ectopic tooth eruption. Ectopic teeth located within the maxillary sinus may be asymptomatic, found only in routine examinations. Headache, sinusitis and nasal obstruction are some of the associated symptoms. The differential diagnosis includes foreign bodies (rhinolith, infections (syphilis and tuberculosis, benign lesions (hemangioma, osteoma, calcifi ed polyp and malign lesions (osteosarcoma. Upper third molars located within the maxillary sinus may be associated with the development of mucocele or dentigerous cyst. The aim of this paper was to describe the case of a 24-year old female patient with an ectopic right upper third molar in the maxillary sinus. A hyperdense area was observed with sinus obliteration, consistent with mucous material.

  16. Ectopic third molar in the maxillary sinus

    OpenAIRE

    Mohan, Shishir; Kankariya, Hasti; Harjani, Bhupendra; Sharma, Harendra

    2011-01-01

    Ectopic eruption of teeth into a region other than the oral cavity is rare although there have been reports of teeth in the nasal septum, mandibular condyle, coronoid process, palate, chin and maxillary sinus. Occasionally, a tooth may erupt in the maxillary sinus and present with local sinonasal symptoms attributed to chronic sinusitis. We present a case of an ectopic maxillary third molar tooth that caused chronic purulent sinusitis in relation to the right maxillary sinus.

  17. Dens in dente of maxillary third molar

    Directory of Open Access Journals (Sweden)

    Subramaniam Arun

    2008-01-01

    Full Text Available ′Dens in dente,′ also known as dens invaginatus, is a developmental anomaly resulting from deepening or invagination of the enamel organ into the dental papilla, which begins at the crown and often extends to the root before calcification of the dental tissues. Dens in dente commonly occur in the maxillary lateral incisor. This article reports a case of dens in dente in the maxillary third molar.

  18. Positional changes of the third molar in orthodontically treated patients

    OpenAIRE

    2013-01-01

    Objective and Rationale. Over the years, the effects of the third molars eruption on the dental arches have been studied extensively. Still, literature provides less data regarding the effects of the orthodontic treatment on the third molars position. The aim of our study was to assess the positional changes of the third molars relative to the occlusal plane and to the second molar long axis, changes occurred during orthodontic treatment performed with or without premolar extractions. Method....

  19. Efficacy and safety of combined piroxicam, dexamethasone, orphenadrine, and cyanocobalamin treatment in mandibular molar surgery

    Directory of Open Access Journals (Sweden)

    A.B. Barroso

    Full Text Available Third molar extraction is a common procedure frequently accompanied by moderate or severe pain, and involves sufficient numbers of patients to make studies relatively easy to perform. The aim of the present study was to determine the efficacy and safety of the therapeutic combination of 10 mg piroxicam, 1 mg dexamethasone, 35 mg orphenadrine citrate, and 2.5 mg cyanocobalamin (Rheumazin® when compared with 20 mg piroxicam alone (Feldene® in mandibular third molar surgery. Eighty patients scheduled for removal of the third molar were included in this randomized and double-blind study. They received (vo Rheumazin or Feldene 30 min after tooth extraction and once daily for 4 consecutive days. Pain was determined by a visual analogue scale and by the need for escape analgesia (paracetamol. Facial swelling was evaluated with a measuring tape and adverse effects and patient satisfaction were recorded. There was no statistically significant difference in facial swelling between Rheumazin and Feldene (control group. Both drugs were equally effective in the control of pain, with Rheumazin displaying less adverse effects than Feldene. Therefore, Rheumazin appears to provide a better risk/benefit ratio in the mandibular molar surgery. Since the side effects resulting from nonsteroidal anti-inflammatory drug administration are a severe limitation to the routine use of these drugs in clinical practice, our results suggest that Rheumazin can be a good choice for third molar removal treatment.

  20. Efficacy and safety of combined piroxicam, dexamethasone, orphenadrine, and cyanocobalamin treatment in mandibular molar surgery

    Directory of Open Access Journals (Sweden)

    Barroso A.B.

    2006-01-01

    Full Text Available Third molar extraction is a common procedure frequently accompanied by moderate or severe pain, and involves sufficient numbers of patients to make studies relatively easy to perform. The aim of the present study was to determine the efficacy and safety of the therapeutic combination of 10 mg piroxicam, 1 mg dexamethasone, 35 mg orphenadrine citrate, and 2.5 mg cyanocobalamin (Rheumazin® when compared with 20 mg piroxicam alone (Feldene® in mandibular third molar surgery. Eighty patients scheduled for removal of the third molar were included in this randomized and double-blind study. They received (vo Rheumazin or Feldene 30 min after tooth extraction and once daily for 4 consecutive days. Pain was determined by a visual analogue scale and by the need for escape analgesia (paracetamol. Facial swelling was evaluated with a measuring tape and adverse effects and patient satisfaction were recorded. There was no statistically significant difference in facial swelling between Rheumazin and Feldene (control group. Both drugs were equally effective in the control of pain, with Rheumazin displaying less adverse effects than Feldene. Therefore, Rheumazin appears to provide a better risk/benefit ratio in the mandibular molar surgery. Since the side effects resulting from nonsteroidal anti-inflammatory drug administration are a severe limitation to the routine use of these drugs in clinical practice, our results suggest that Rheumazin can be a good choice for third molar removal treatment.

  1. Cusp expression of protostylid in deciduous and permanent molars

    Science.gov (United States)

    Moreno, Sandra; Reyes, María Paula; Moreno, Freddy

    2016-01-01

    The present article is a case report on the cusp expression of protostylid in the deciduous inferior molars and in the first permanent inferior molar, in which the correspondence and bilateral symmetry of the mentioned expression can be evidenced, as well as the their relation with the foramen cecum of the mesiobuccal furrows of the deciduous and of the permanent inferior molars. PMID:28123270

  2. Structural study and crystallography of the major compound of anhydrous cement: tri-calcium silicate; Etude structurale et cristallographie du compose majoritaire du ciment anhydre: le silicate tricalcique

    Energy Technology Data Exchange (ETDEWEB)

    Noirfontaine, M.N. de

    2000-01-01

    Anhydrous (Portland) cement is mainly composed of a synthetic material, the clinker, whose major compound is tri-calcium silicate (Ca{sub 3}SiO{sub 5}), often referred as C{sub 3}S with the compact oxides notations, C = CaO et S = SiO{sub 2}. The polymorphism of C{sub 3}S, still not well known, is the main subject of the thesis. Various crystal structures (rhombohedral R, monoclinic M1, M2, M3 and triclinic T1, T2, T3) can be found, depending on temperature and impurities. The only known structures are T1, M1 and M3, involving large unit cells with an orientational disorder of silicate tetrahedra. The single crystal studies exhibit no clear relation between the various polymorphs. Starting from known results from literature single crystal experiments, we establish the metric and structural relations between the different structures. Averaged structures for the T1, M1 and M3 polymorphs are proposed, together with all the matrices of transformation between the unit cells. We also introduce new 1-D, 2-D, and 3-D structural units, which make easier the understanding of the structures of C{sub 3}S, with the result of a better description of the orientational disorder. The effects of impurities on the structure are discussed. In industrial clinkers, impurities stabilize mainly M1 and M3 monoclinic forms. We propose a space group (Pc) and two structural models (a superstructure and an approximate averaged structure) for the M1 form. All the models are validated on synthetic compounds (M3, M2, M1 et T1) and industrial clinkers analysed by X-Ray powder diffraction with Rietveld analysis. (author)

  3. Correlated Nitrogen And Carbon Anomalies In An Anhydrous Interplanetary Dust Particles

    Energy Technology Data Exchange (ETDEWEB)

    Floss, C; Stadermann, F J; Bradley, J; Dai, Z; Graham, G

    2003-10-31

    Given the ubiquitous presence of H and N isotopic anomalies in interplanetary dust particles (IDPs) and their probable association with carbonaceous material, the lack of similar isotopic anomalies in C has been a major conundrum. We report here the first observation of correlated N and C isotopic anomalies in organic matter from an anhydrous non-cluster IDP. The {sup 15}N composition of the anomalous region is the highest seen to date in an IDP and is accompanied by a moderate depletion in {sup 13}C. Theoretical models suggest that low temperature formation of organic compounds in cold interstellar molecular clouds does produce C and N fractionations, but it remains to be seen if these models can reproduce the specific effects we observe here.

  4. Crystallization behavior of anhydrous milk fat-sunflower oil wax blends.

    Science.gov (United States)

    Kerr, Rebekah M; Tombokan, Xenia; Ghosh, Supriyo; Martini, Silvana

    2011-03-23

    This research evaluates the effect of sunflower oil wax (SFOw) addition on the crystallization behavior and functional properties of anhydrous milk fat (AMF). Induction times of nucleation, melting behavior, microstructure of crystals, and hardness were evaluated for samples of pure AMF and AMF with 0.1 and 0.25% SFOw. Results from this research show that the addition of waxes induced the onset of crystallization of AMF by inducing its nucleation, as evidenced by decreased induction times of nucleation and the formation of smaller crystals. Crystal growth after tempering was also promoted by waxes, and significantly harder lipid networks were obtained. Results presented in this paper suggest that SFOw can be used as an additive to alter the physiochemical properties of low trans-fatty acid lipids.

  5. Detection of anhydrous hydrochloric acid, HCl, in IRC+10216 with the Herschel SPIRE and PACS spectrometers

    CERN Document Server

    Cernicharo, J; Barlow, M J; Agundez, M; Royer, P; Vandenbussche, B; Wesson, R; Polehampton, E T; De Beck, E; Blommaert, J A D L; Daniel, F; De Meester, W; Exter, K M; Feuchtgruber, H; Gear, W K; Goicoechea, J R; Gomez, H L; Groenewegen, M A T; Hargrave, P C; Huygen, R; Imhof, P; Ivison, R J; Jean, C; Kerschbaum, F; Leeks, S J; Lim, T L; Matsuura, M; Olofsson, G; Posch, T; Regibo, S; Savini, G; Sibthorpe, B; Swinyard, B M; Vandenbussche, B; Waelkens, C

    2010-01-01

    We report on the detection of anhydrous hydrochloric acid (hydrogen chlorine, HCl) in the carbon-rich star IRC+10216 using the spectroscopic facilities onboard the Herschel satellite. Lines from J=1-0 up to J=7-6 have been detected. From the observed intensities, we conclude that HCl is produced in the innermost layers of the circumstellar envelope with an abundance relative to H2 of 5x10^-8 and extends until the molecules reach its photodissociation zone. Upper limits to the column densities of AlH, MgH, CaH, CuH, KH, NaH, FeH, and other diatomic hydrides have also been obtained.

  6. Highly Efficient and Versatile Synthesis of Some Important Precursors from 1,6-Anhydrous-β-D-glucopyranose as a Green Starting Material

    Institute of Scientific and Technical Information of China (English)

    WEI Guohua; CAI Chao; DU Yuguo

    2009-01-01

    Some important precursors (1,6-anhydrous-2-deoxy-2-azido-β-D-glucopyranose (3),1,6-anhydrous-2-deoxy-2-azido-3,4-di-O-benzyl-β-D-mannopyranose (5), 1,6:2,3-dianhydrouso-β-D-glucopyranose (6), 1,6-anhydrous-3-deoxy-3-azido-β-D-glucopyranose (10) and 1,6-anhydrous-2,4-di-O-benzoyl-β-D-glucopyranose (11)) for complex oligosaccharide synthesis were readily prepared from a green starting material 1,6-anhydrous-β-D-glucopyranose in one or two steps with moderate to high yields.These improved methods established herein will greatly facilitate the assembly of some complex oligosaccharides for the biological study.

  7. Effects of coffee and caffeine anhydrous on strength and sprint performance.

    Science.gov (United States)

    Trexler, Eric T; Smith-Ryan, Abbie E; Roelofs, Erica J; Hirsch, Katie R; Mock, Meredith G

    2016-09-01

    Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300 mg flat dose; yielding 3-5 mg/kg bodyweight), COF (8.9 g; 303 mg caffeine), or placebo (PLA; 3.8 g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p = .04), but not PLA (p = .99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p > .05). There were no sprint × treatment interactions for PP or TW (p > .05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.

  8. Distribution and recovery of nitrogen-15-labeled liquid anhydrous ammonia among various soil fractions

    Energy Technology Data Exchange (ETDEWEB)

    Norman, R.J.; Kurtz, L.T.; Stevenson, F.J.

    Since liquid anhydrous ammonia (LAA) is a major N fertilizer, information was sought about the proportions of LAA that enter into various combinations in soils. Liquid anhydrous NH/sub 3/, labeled with /sup 15/N was injected into three soils (Drummer, Typic Haplaquoll; Blount, Aeric Ochraqualf; Cisne, Mollic Albaqualf) in the laboratory at a rate equivalent to a field application of 206 kg N ha /sup 1/ in 76.2 cm knife-spacings. At 1, 7, 14, 28, 56, and 112 d after application, fertilizer N present in different soil fractions was determined in five concentric zones with radii of 0 to 1.5, 1.5 to 3.0, 3.0 to 4.5, 4.5 to 6.0, and 6.0 to 7.0 cm around the point of application. Depending on the soil, from 68 to 83% of the applied /sup 15/N was accounted for as (exchangeable NH/sub 4//sup +/ + NO/sub 3//sup -/ + NO/sub 2//sup -/)-N by the 112th day following application, the remainder being accounted for as clay-fixed NH/sub 4//sup +/ (1.9-4.9%), organic matter-fixed NH/sub 3/ (4.0-6.0%), and biologically immobilized organic N (3.9-9.3%). From 50 to 70% of the organic matter-fixed NH/sub 3/-N was released by hydrolysis with dilute KOH solution as compared to 10 to 15% for the immobilized N. Total recovery of /sup 15/N at 112 d ranged from 77% for the Cisne soil to about 97% for the Drummer and Blount soils. Lateral distributions and transformations of NH/sub 4//sup +/ and NO/sub 3//sup -/ and pH trends after LAA applications were similar to those reported by previous investigators.

  9. Composite polymer electrolyte containing ionic liquid and functionalized polyhedral oligomeric silsesquioxanes for anhydrous PEM applications.

    Science.gov (United States)

    Subianto, Surya; Mistry, Mayur K; Choudhury, Namita Roy; Dutta, Naba K; Knott, Robert

    2009-06-01

    A new type of supported liquid membrane was made by combining an ionic liquid (IL) with a Nafion membrane reinforced with multifunctional polyhedral oligomeric silsesquioxanes (POSSs) using a layer-by-layer strategy for anhydrous proton-exchange membrane (PEM) application. The POSS was functionalized by direct sulfonation, and the sulfonated POSS (S-POSS) was incorporated into Nafion 117 membranes by the infiltration method. The resultant hybrid membrane shows strong ionic interaction between the Nafion matrix and the multifunctional POSS, resulting in increased glass transition temperature and thermal stability at very low loadings of S-POSS (1%). The presence of S-POSS has also improved the proton conductivity especially at low humidities, where it shows a marked increase due to its confinement in the ionic domains and promotes water uptake by capillary condensation. In order to achieve anhydrous conductivity, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) was incorporated into these membranes to provide proton conduction in the absence of water. Although the incorporation of an IL shows a plasticizing effect on the Nafion membrane, the S-POSS composite membrane with an IL shows a higher modulus at high temperatures compared to Nafion 117 and a Nafion-IL membrane, with significantly higher proton conductivity (5 mS/cm at 150 degrees C with 20% IL). This shows the ability of the multifunctional POSS and IL to work symbiotically to achieve the desirable proton conductivity and mechanical properties of such membranes by enhancing the ionic interaction within the material.

  10. Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

    NARCIS (Netherlands)

    Livas, Christos; Pandis, Nikolaos; Booij, Johan Willem; Halazonetis, Demetrios J.; Katsaros, Christos; Ren, Yijin

    2016-01-01

    Objective: To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction. Materials and Methods: Panoramic radiographs of 21 Class II subdivision adolescents (eight

  11. Biomarker generation from Type II-S kerogens in claystone and limestone during hydrous and anhydrous pyrolysis

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Koopmans, M.P.; Carson, F.C.; Lewan, M.D.

    1998-01-01

    A claystone and a limestone containing immature Type II-S kerogen were thermally matured in the presence and absence of water, to study the influence of water and clay minerals on the generation of biomarkers. In contrast to hydrous pyrolysis, anhydrous pyrolysis of the claystone did not generate bi

  12. 75 FR 70687 - Storage and Handling of Anhydrous Ammonia Standard; Extension of the Office of Management and...

    Science.gov (United States)

    2010-11-18

    ... containers and systems to store and transfer anhydrous ammonia in the workplace. DATES: Comments must be... INFORMATION.'' Docket: To read or download comments or other material in the docket, go to http://www....g., copyrighted material) is not publicly available to read or download through the Web site....

  13. 78 FR 78393 - Standard on the Storage and Handling of Anhydrous Ammonia; Extension of the Office of Management...

    Science.gov (United States)

    2013-12-26

    ... containers and systems to store and transfer anhydrous ammonia in the workplace. DATES: Comments must be... material in the docket, go to http://www.regulations.gov or the OSHA Docket Office at the address above....regulations.gov index; however, some information (e.g., copyrighted material) is not publicly available...

  14. TEM and NanoSIMS Study of Hydrated/Anhydrous Phase Mixed IDPs: Cometary or Asteroidal Origin?

    Science.gov (United States)

    Nakamura, K.; Messenger, S.; Keller, L. P.

    2005-01-01

    Chondritic interplanetary dust particles (IDPs) are subdivided into (1) particles that form highly porous aggregates (chondritic porous "CP" IDPs), and (2) smooth particles ("CS" IDPs). Infrared (IR) spectroscopy has been a valuable tool for non-destructively determining the bulk mineralogy of IDPs. Most IDPs fall within three distinct IR groups: (1) olivine-rich particles, (2) pyroxene-rich particles, and (3) phyllosilicate-rich particles. From the IR studies, IDPs dominated by anhydrous minerals tend to be fine grained (CP), while phyllosilicate-rich IDPs are mostly CS. CP IDPs have been linked to cometary sources based on their compositions, spectral properties, and atmospheric entry velocities. Since no spectral signatures of hydrated minerals have been detected in comets, CS IDPs are thought to derive from primitive asteroids. Transmission electron microscopy (TEM) studies have revealed that the mineralogical distinctions between CP and CS IDPs are not always clear. Previous investigators have reported trace amounts of hydrous minerals in dominantly anhydrous particles. A better understanding of these particles will help to elucidate whether there is a genetic relationship between anhydrous and hydrated IDPs, provide insight into the earliest stages of aqueous alteration of primitive materials, and may help to determine whether comets have experienced any aqueous processing. Here we report a combined TEM and isotopic imaging study of an unusual anhydrous IDP with hydrated phases. Additional information is included in the original extended abstract.

  15. Crystal structure of aspartame anhydrate from powder diffraction data. Structural aspects of the dehydration process of aspartame

    NARCIS (Netherlands)

    Guguta, C.; Meekes, H.L.M.; Gelder, R. de

    2006-01-01

    Aspartame has three pseudo-polymorphic forms, two hydrates and a hemi-hydrate, for which crystal structures were determined from single-crystal diffraction data. This paper presents the crystal structure of the anhydrate, which was obtained by dehydrating the hemi-hydrate. The crystal structure of a

  16. Anhydrous ZnCl2: A Highly Efficient Reagent for Facile and Regioselective Conversion of Epoxides to β-Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Ronak Eisavi

    2016-01-01

    Full Text Available Facile conversion of structurally different epoxides to the corresponding β-chlorohydrins was carried out successfully with anhydrous ZnCl2 in CH3CN. The reactions were carried out within 10-50 min to give β-chlorohydrins with perfect regioselectivity and high yields (80-97%.

  17. PENARIKAN GIGI MOLAR IMPAKSI PADA RAHANG BAWAH (Laporan Kasus

    Directory of Open Access Journals (Sweden)

    Debora Hidayat

    2015-08-01

    Full Text Available Impacted mandibular molars often caused by locking of the adjacent teeth, lack of space and many other reasons. Surgical extraction used to be the first choice in treating the severely impacted molars. In this article, firstly a horizontally impacted mandibular first molar and a mandibular second molar were diagnosed radiographically. By surgical crown exposure, combined with elastic traction, the teeth can be pulled occlusally into proper position. However, a thorough observation to control the position of the impacted molars during traction is still necessary.

  18. Complications of third molar surgery and their management.

    Science.gov (United States)

    Marciani, Robert D

    2012-09-01

    The frequency and severity of untoward events associated with surgical procedures are influenced by multiple factors that may be related to the procedure, patient, and/or surgeon. Not every third molar needs to be removed. Full bony impacted lower third molars well below the cervical margin of the second molar crowns should be considered for retention. Certain deviations from normal healing should be considered to be complications. Risk factors associated with third molar removal should be carefully established and explained to the patient. Third molar surgery has a predictable postsoperative course for the average patient.

  19. Radiologic study of mandibular third molar of Korean youths

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Hyung Kyu [Dept. of Oral Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1982-11-15

    The author has made a study on the classification of the mandibular 3rd molars of Korean youths through dental radiography by means of Pell and Gregory's classification and on the prevalence of the dental caries of distal surface of the mandibular 2nd molar adjacent to the mandibular 3rd molars turned anteriorly. The results are as follow; 1. It was found that the largest case number was class I (272 cases, 52.9%) in the relation of the tooth to the ramus of the mandible and 2nd molar. 2. The mesio-angular position was the largest number (239 cases, 46.5%) in the relation of the long axis of the impacted mandibular 3rd molar to the long axis of the 2nd molar. 3. The mesio-angular position of class I was the largest number (140 cases, 27.2%) in the relation of the tooth to the ramus of the mandible and 2nd molar and the long axis of the impacted mandibular 3rd moral to the long axis of the 2nd molar. 4. The average angle of the long axis of mandibular 3rd molar in mesioangular position or horizontal position to the occlusal plane was 143 W 5. Mandibular 3rd molar with lesion such as dental cries or pericoronitis was 73 cases (14.2). 6. The caries incidence rate of the distal surface of the 2nd molar was about 3.1%.

  20. Bilateral lower second molar impaction in teenagers: an emergent problem?

    Science.gov (United States)

    Shinohara, Elio H; Kaba, Shajadi Carlos Pardo; Pedron, Irineu Gregnanin; Imparato, Jose Carlos Petorossi

    2010-01-01

    The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impacted third molar for the eruption of the second molar through a vestibular incision. This incision offers excellent bone exposure and exit route for the third molar without disturbing the gingiva attached architecture on the distal face of the first molar providing good healing environment.

  1. Bilateral lower second molar impaction in teenagers: An emergent problem?

    Directory of Open Access Journals (Sweden)

    Shinohara Elio

    2010-01-01

    Full Text Available The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impacted third molar for the eruption of the second molar through a vestibular incision. This incision offers excellent bone exposure and exit route for the third molar without disturbing the gingiva attached architecture on the distal face of the first molar providing good healing environment.

  2. Angle Class II, subdivision, with agenesis of mandibular second molars and extrusion of maxillary second molars

    Directory of Open Access Journals (Sweden)

    Rubens Rodrigues Tavares

    2015-04-01

    Full Text Available This clinical case reports the treatment of an Angle Class II malocclusion in a young woman with a balanced face affected by agenesis of second and third mandibular molars and subsequent extrusion of second maxillary molars. The atypical and peculiar occlusal anomaly led to individualized treatment proposed in order to normalize dental malpositions, with subsequent rehabilitation of edentulous areas by means of a multidisciplinary approach. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO in partial fulfillment of the requirements for obtaining the title of certified by the BBO.

  3. Molar Pregnancy Presents as Tubal Ectopic Pregnancy

    Directory of Open Access Journals (Sweden)

    Fatemeh Davari Tanha

    2011-01-01

    Full Text Available Hydatidiform moles are abnormal gestations characterized by the presence of hydropic changesaffecting some or all of the placental villi. Hydatidiform moles arise as a result of the fertilizationof an abnormal ovum. In this report, the patient was a 29 year old Asian woman who had inductionof ovulation with letrozol. Since the majority of molar gestations arise within the uterine cavitythus the occurrence of a hydatidiform mole within ectopic gestational tissue is rare. It is importantto differentiate a hydatidiform mole from a conventional ectopic pregnancy, particularly in infertilewomen who have a history of ovulation induction.

  4. [Ectopic molar tooth in the maxillary sinus].

    Science.gov (United States)

    Altun, Hüseyin; Teker, Ayşenur Meriç; Ceran, Murat; Gedikli, Orhan

    2007-01-01

    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.

  5. Antibiotic therapy in impacted third molar surgery.

    Science.gov (United States)

    Monaco, G; Staffolani, C; Gatto, M R; Checchi, L

    1999-12-01

    The use of routine antibiotic therapy in patients undergoing surgical third molar extraction is controversial. The efficacy of antibiotic therapy in preventing postoperative complications following surgical third molar extractions was evaluated in 141 patients. In the test group (66 patients), the protocol utilized a regimen of 2 g of amoxicillin orally daily for 5 d postoperatively, starting at the completion of surgery. In the control group (75 patients), no antibiotic therapy was given. No significant difference was found between the test group and the control group in the incidence of postoperative sequelae, i.e. fever, pain, swelling and alveolar osteitis. A statistically significant association between smoking, habitual drinking and increased postoperative pain and fever was found. Patient age > or = 18 yr was positively correlated with an increased incidence of alveolar osteitis. Swelling was found to be gender-related, in that female patients experienced more swelling than male patients. No correlation was found between the time required for surgery or difficulty of extraction and post-operative pain. In conclusion, no difference was found between patients receiving postoperative amoxicillin and the control group in the incidence of postoperative sequelae.

  6. Molar incisor hypomineralization, prevalence, and etiology.

    Science.gov (United States)

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

    2014-01-01

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

  7. Molar Incisor Hypomineralization, Prevalence, and Etiology

    Directory of Open Access Journals (Sweden)

    Sulaiman Mohammed Allazzam

    2014-01-01

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

  8. Onset of molar incisor hypomineralization (MIH).

    Science.gov (United States)

    Fagrell, Tobias G; Salmon, Phil; Melin, Lisa; Norén, Jörgen G

    2013-01-01

    The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age.

  9. Clinical significance of computed tomography assessment for third molar surgery

    Institute of Scientific and Technical Information of China (English)

    Kenji; Nakamori; Kei; Tomihara; Makoto; Noguchi

    2014-01-01

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

  10. Clinical significance of computed tomography assessment for third molar surgery.

    Science.gov (United States)

    Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

    2014-07-28

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

  11. The Role of Hydrogen Bonding on Laminar Burning Velocity of Hydrous and Anhydrous Ethanol Fuel with Small Addition of n-Heptane

    Directory of Open Access Journals (Sweden)

    I Made Suarta

    2016-01-01

    Full Text Available The molecular structure of mixed hydrous and anhydrous ethanol with up to 10% v n-heptane had been studied. The burning velocity was examined in a cylindrical explosion combustion chamber. The result showed that the burning velocity of hydrous ethanol is higher than anhydrous ethanol and n-heptane at stoichiometric, rich, and very rich mixtures. The burning velocity of hydrous ethanol with n-heptane drops drastically compared to the burning velocity of anhydrous ethanol with n-heptane. It is caused by two reasons. Firstly, there was a composition change of azeotropic hydrous ethanol molecules within the mixture of fuel. Secondly, at the same volume the number of ethanol molecules in hydrous ethanol was less than in anhydrous ethanol at the same composition of the n-heptane in the mixture. At the mixture of anhydrous ethanol with n-heptane, the burning velocity decreases proportionally to the addition of the n-heptane composition. The burning velocity is between the velocities of anhydrous ethanol and n-heptane. It shows that the burning velocity of anhydrous ethanol mixed with n-heptane is only influenced by the mixture composition.

  12. Extrações de molares na Ortodontia Molar extractions in orthodontics

    Directory of Open Access Journals (Sweden)

    Marco Antônio Schroeder

    2011-12-01

    Full Text Available O tratamento ortodôntico com extração de molares em pacientes adultos é tecnicamente mais complexo, devido a inúmeros fatores. Em geral, o espaço a ser fechado é maior do que o espaço dos pré-molares e, por isso, a ancoragem é crítica e o tempo de tratamento mais longo. É comum esses casos apresentarem algum grau de comprometimento periodontal por causa da idade dos pacientes e, portanto, necessitam de maior controle da mecânica ortodôntica para reduzir os efeitos colaterais do fechamento do espaço. Por isso, bons resultados de finalização são mais difíceis de ser alcançados. Sendo assim, este artigo tem como objetivo apresentar as razões para a indicação de extração de molares nos tratamentos ortodônticos, as contraindicações, as diferentes fases da mecânica ortodôntica, esclarecer os fatores envolvidos nesse tipo de planejamento e tratamento e apresentar casos clínicos tratados com extração de molares.Orthodontic treatment with extraction of molars in adult patients is technically more complex due to a number of factors. In general, the space to be closed is greater than premolar spaces rendering critical anchorage and longer treatment time. Often such cases exhibit some degree of periodontal involvement due to patient age. Hence, the need for greater control over orthodontic mechanics to reduce the side effects of space closure. Therefore, good finishing results can be more difficult to achieve. Thus, the purpose of this article is to determine the reasons for molar extraction indications, describe different stages of orthodontic mechanics, and explain the issues involved in this kind of planning and treatment. Additionally, it aims at describing some treatments with molar extractions.

  13. Preparation and Characterization of Anhydrous Magnesium Chloride in Organic Solvent%有机溶剂法无水氯化镁的制备与表征

    Institute of Scientific and Technical Information of China (English)

    周宁波; 陈白珍; 何新快; 李义兵

    2005-01-01

    Ammonium carnallite was synthesized by hydrated magnesium chloride in salt lake and ammonium chloride solution. Dehydrated ammonium carnallite was dissolved in methanol under low temperature by feeding ammonia, to prepare anhydrous magnesium chloride. The results show that anhydrous magnesium chloride contains magnesium oxide in an amount less than 0.1% by weight, the yield of magnesium chloride was above 99.5%. Ammonium carnallite, ammoniation magnesium chloride and anhydrous magnesium chloride were characterized by thermoanalysis, X-ray powder diffraction and scanning electron microscopy.

  14. Displacement of maxillary third molar into the lateral pharyngeal space.

    Science.gov (United States)

    Lee, Doksa; Ishii, Syoichiro; Yakushiji, Noboru

    2013-10-01

    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.

  15. Autotransplantation of Mandibular Third Molar: A Case Report

    Directory of Open Access Journals (Sweden)

    Pabbati Ravi kumar

    2012-01-01

    Full Text Available 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.

  16. Effect of Ca/Al molar ratio on the growth of Cryptomeria japonica, Chamaecyparis obtusa and Chamaecyparis pisifera grown in nutrient solution culture and their critical point; Suiko saibai jokenka ni okeru sugi, hinoki, sawara no seiiku ni oyobosu Ca/Al no eikyo to critical point

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Y. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Umezawa, T.; Murakoshi, M. [Bio-Environment Research, Co. Ltd., Chiba (Japan)

    1998-11-10

    A solution culture is experimented for the investigation of the effect of Ca/Al on the growth of Sugi (cryptomeria), Hinoki (cypress), and Sakura (cherry tree), and of CP (critical point for the emergence of the effect of Al). The solution culture is performed in water under specified conditions, the harvest is assortedly collected after 14 weeks, and is measured for dried weight. Sugi and Hinoki wither and die at an Al concentration of 5mM, but not at an Al concentration of 1mM or less. The concentration of Ca fails to exert any significant influence. At the Al concentration of 5mM, the trees are inhibited from growing in height or trunk diameter, but not affected by Ca concentration. The dried weight shares the same trend. The dried weight begins to decrease when the mol concentration ratio of Ca/Al or (K+Ca+Mg)/Al lowers to four or less. It may be concluded that conifers are inhibited from growing when the Al concentration is 2mM or higher, Ca/Al is one or lower, or (K+Ca+Mg)/Al is five or lower. If the point where growth is inhibited by 20% or 50% is chosen as the reference point, the CP of (K+Ca+Mg)/Al will be 1 or 0.5, respectively. This means that a different reference point yields a different value. There is an experimental outcome stating that growth is not affected even when this value is 0.4 in the case of soil exposed to artificial acid rain. 22 refs., 9 figs., 1 tab.

  17. Bilateral lower second molar impaction in teenagers: An emergent problem?

    OpenAIRE

    Shinohara Elio; Kaba Shajadi; Pedron Irineu; Imparato Jose

    2010-01-01

    The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impa...

  18. Some morphological features related to mandibular third molar impaction

    OpenAIRE

    Kaya, Göksel Şimşek; ASLAN, MUZAFFER; Omezli, M. Melih; DAYI, Ertunç

    2010-01-01

    Objective: The aim of this study was to evaluate the effect of some morphological features of the mandible and mandibular permanent molars on impaction of mandibular third molars with panoramic measurements in a Turkish patient group. Study design: Standardized panoramic radiography variables compiled from 140 patients retrospectively were eva- luated. Predictive variables included mesio-distal crown width and inclination of the mandibular molars, vertical and horizo...

  19. Estudio anatómico del tercer molar mandibular incluido

    OpenAIRE

    Larrazabal Morón, Carolina

    2015-01-01

    Los terceros molares son los últimos dientes en erupcionar, debido a ello no encuentran suficiente espacio para establecerse en el arco dentario, por lo que fácilmente pueden quedar retenidos. El diagnóstico inadecuado del tercer molar inferior incluido puede ser causa de numerosas complicaciones como infecciones odontogénicas, tumores benignos, malignos, caries dental entre otros. Por ello el objetivo de este estudio es conocer el desarrollo del tercer molar mandibular, analizar los c...

  20. Possibilty of the lower third molar eruption: Radiographic analysis

    OpenAIRE

    2006-01-01

    Backgraund/Aim. To assess the possibility of the eruption of the lower third molar on the basis of the measured parameters: retromolar space, mesiodistal crown width of a molar and the third molar angulation. Methods. The investigation included 104 patients both sexes (43 boys, and 61 girls), 16 to 25 years old (meanage, 18 years). It was performed using the orthopanthomographic radiographs analysis of those patients. Each radiograph was covered by tracing paper, and the contoures of the foll...

  1. Molar incisor hypomineralization: an aesthetic conservative restorative approach

    OpenAIRE

    Silva-junior, Manoelito Ferreira; Assis,Rahyza Inácio Freire de; PAZINATTO,Flávia Bittencourt

    2016-01-01

    ABSTRACT The aim this study is to present a clinical case of conservative aesthetic restorative treatment of teeth 11 and 21 in a patient diagnosed with molar incisor hypomineralization. An 18-year-old female patient came to the Outpatient Restorative Dentistry Clinic at the Federal University of Espírito Santo, complaining mainly of not feeling comfortable with a color change in her anterior teeth. Molar incisor hypomineralization was diagnosed in molars and incisors and the negative psychos...

  2. Ceramic onlay for endodontically treated mandibular molar

    Directory of Open Access Journals (Sweden)

    Roopadevi Garlapati

    2014-01-01

    Full Text Available Restoration of endodontically treated teeth is important for the success of endodontic treatment. In full coverage restorations, maximum amount of tooth structure is compromised, so as to conserve the amount of tooth structure partial coverage restorations, can be preferred. This case report is on fabrication of a conservative tooth colored restoration for an endodontically treated posterior tooth. A 22-year-old male patient presented with pain in the mandibular left first molar. After endodontic treatment, composite material was used as postendodontic restoration. The tooth was then prepared to receive a ceramic onlay and bonded with self-adhesive universal resin cement. Ceramic onlay restoration was periodically examined up to 2 years.

  3. Stepwise excavation in a permanent molar

    DEFF Research Database (Denmark)

    Lima, Fernanda Ferruzzi; Pascotto, Renata Corrêa; Benetti, Ana Raquel

    2010-01-01

    The current study presents a 17-year clinical report of stepwise excavation and indirect pulp capping in a lower right first molar, with great dentin destruction and a lack of dentin support of the cusps. At the first appointment, indirect pulp capping with calcium hydroxide and a temporary filling...... with zinc oxide cement were performed to minimize the risk of pulp exposure during excavation. After 45 days, the remaining carious tissue was removed and a restoration with glass-ionomer lining (Vitrebond) and resin composite (P-50) was performed. Satisfactory morphology and function of the restoration...... and pulp vitality were preserved for 17 years, thus indicating that stepwise excavation can be a good treatment alternative in selected cases....

  4. Molar extinction coefficients of some fatty acids

    Science.gov (United States)

    Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

    2002-10-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

  5. Amoxicillin may cause molar incisor hypomineralization.

    Science.gov (United States)

    Laisi, S; Ess, A; Sahlberg, C; Arvio, P; Lukinmaa, P-L; Alaluusua, S

    2009-02-01

    The etiology of molar incisor hypomineralization (MIH) is unclear. Our hypothesis was that certain antibiotics cause MIH. We examined 141 schoolchildren for MIH and, from their medical files, recorded the use of antibiotics under the age of 4 yrs. MIH was found in 16.3% of children. MIH was more common among those children who had taken, during the first year of life, amoxicillin (OR=2.06; 95% CI, 1.01-4.17) or the rarely prescribed erythromycin (OR=4.14; 95% CI, 1.05-16.4), compared with children who had not received treatment. Mouse E18 teeth were cultured for 10 days with/without amoxicillin at concentrations of 100 microg/mL-4 mg/mL. Amoxicillin increased enamel but not dentin thickness. An altered pattern of amelogenesis may have interfered with mineralization. We conclude that the early use of amoxicillin is among the causative factors of MIH.

  6. Vibrational Spectroscopy and Phonon-Related Properties of the L-Aspartic Acid Anhydrous Monoclinic Crystal.

    Science.gov (United States)

    Silva, A M; Costa, S N; Sales, F A M; Freire, V N; Bezerra, E M; Santos, R P; Fulco, U L; Albuquerque, E L; Caetano, E W S

    2015-12-10

    The infrared absorption and Raman scattering spectra of the monoclinic P21 l-aspartic acid anhydrous crystal were recorded and interpreted with the help of density functional theory (DFT) calculations. The effect of dispersive forces was taken into account, and the optimized unit cells allowed us to obtain the vibrational normal modes. The computed data exhibits good agreement with the measurements for low wavenumbers, allowing for a very good assignment of the infrared and Raman spectral features. The vibrational spectra of the two lowest energy conformers of the l-aspartic molecule were also evaluated using the hybrid B3LYP functional for the sake of comparison, showing that the molecular calculations give a limited description of the measured IR and Raman spectra of the l-aspartic acid crystal for wavenumbers below 1000 cm(-1). The results obtained reinforce the need to use solid-state calculations to describe the vibrational properties of molecular crystals instead of calculations for a single isolated molecule picture even for wavenumbers beyond the range usually associated with lattice modes (200 cm(-1) < ω < 1000 cm(-1)).

  7. Taste Masking of Griseofulvin and Caffeine Anhydrous Using Kleptose Linecaps DE17 by Hot Melt Extrusion.

    Science.gov (United States)

    Juluri, Abhishek; Popescu, Carmen; Zhou, Leon; Murthy, Reena N; Gowda, Vanaja K; Chetan Kumar, P; Pimparade, Manjeet B; Repka, Michael A; Murthy, S Narasimha

    2016-02-01

    The objective of this project was to investigate the potential of Kleptose Linecaps DE17 (KLD) in masking the unpleasant/bitter taste of therapeutic agents by hot melt extrusion (HME). Griseofulvin (GRI) and caffeine anhydrous (CA) were used as a bitter active pharmaceutical ingredient (API) model drugs. Thermogravimetric studies confirmed the stability of GRI, CA, and KLD at the employed extrusion temperatures. The differential scanning calorimetry (DSC) studies revealed a characteristic melting endotherm of GRI at 218-220°C and CA at 230-232°C in the physical mixtures as well as in all extrudates over the period of study, indicating the crystalline nature of drug. HME of KLD was achieved only in the presence of plasticizer. Among the several plasticizers investigated, xylitol showed improved processability of KLD at 15% w/w concentration. Dissolution studies of HME extrudates using simulated salivary medium exhibited ∼threefold less release compared to physical mixture at the end of 5 min (the lesser drug release, better the taste masking efficiency). Furthermore, the results from the sensory evaluation of products in human panel demonstrated strong bitter taste in the case of physical mixture compared to the HME formulation, suggesting the potential of Kleptose Linecaps DE17 as taste masking polymer in melt extruded form.

  8. Structure, Solubility and Stability of Orbifloxacin Crystal Forms: Hemihydrate versus Anhydrate.

    Science.gov (United States)

    Santos, Olimpia Maria Martins; Freitas, Jennifer Tavares Jacon; Cazedey, Edith Cristina Laignier; de Araújo, Magali Benjamim; Doriguetto, Antonio Carlos

    2016-03-09

    Orbifloxacin (ORBI) is a widely used antimicrobial drug of the fluoroquinolone class. In the official pharmaceutical compendia the existence of polymorphism in this active pharmaceutical ingredient (API) is reported. No crystal structure has been reported for this API and as described in the literature, its solubility is very controversial. Considering that different solid forms of the same API may have different physicochemical properties, these different solubilities may have resulted from analyses inadvertently carried out on different polymorphs. The solubility is the most critical property because it can affect the bioavailability and may compromise the quality of a drug product. The crystalline structure of ORBI determined by SCXRD is reported here for the first time. The structural analysis reveals that the ORBI molecule is zwitterionic and hemihydrated. ORBI hemihydrated form was characterized by the following techniques: TG/DTA, FTIR-ATR, and PXRD. A second crystalline ORBI form is also reported: the ORBI anhydrous form was obtained by heating the hemihydrate. These ORBI solid forms were isomorphous, since no significant change in unit cell and space group symmetry were observed. The solid-state phase transformation between these forms is discussed and the equilibrium solubility data were examined in order to check the impact of the differences observed in their crystalline structures.

  9. Structure, Solubility and Stability of Orbifloxacin Crystal Forms: Hemihydrate versus Anhydrate

    Directory of Open Access Journals (Sweden)

    Olimpia Maria Martins Santos

    2016-03-01

    Full Text Available Orbifloxacin (ORBI is a widely used antimicrobial drug of the fluoroquinolone class. In the official pharmaceutical compendia the existence of polymorphism in this active pharmaceutical ingredient (API is reported. No crystal structure has been reported for this API and as described in the literature, its solubility is very controversial. Considering that different solid forms of the same API may have different physicochemical properties, these different solubilities may have resulted from analyses inadvertently carried out on different polymorphs. The solubility is the most critical property because it can affect the bioavailability and may compromise the quality of a drug product. The crystalline structure of ORBI determined by SCXRD is reported here for the first time. The structural analysis reveals that the ORBI molecule is zwitterionic and hemihydrated. ORBI hemihydrated form was characterized by the following techniques: TG/DTA, FTIR-ATR, and PXRD. A second crystalline ORBI form is also reported: the ORBI anhydrous form was obtained by heating the hemihydrate. These ORBI solid forms were isomorphous, since no significant change in unit cell and space group symmetry were observed. The solid-state phase transformation between these forms is discussed and the equilibrium solubility data were examined in order to check the impact of the differences observed in their crystalline structures.

  10. Laboratory-Scale Membrane Reactor for the Generation of Anhydrous Diazomethane.

    Science.gov (United States)

    Dallinger, Doris; Pinho, Vagner D; Gutmann, Bernhard; Kappe, C Oliver

    2016-07-15

    A configurationally simple and robust semibatch apparatus for the in situ on-demand generation of anhydrous solutions of diazomethane (CH2N2) avoiding distillation methods is presented. Diazomethane is produced by base-mediated decomposition of commercially available Diazald within a semipermeable Teflon AF-2400 tubing and subsequently selectively separated from the tubing into a solvent- and substrate-filled flask (tube-in-flask reactor). Reactions with CH2N2 can therefore be performed directly in the flask without dangerous and labor-intensive purification operations or exposure of the operator to CH2N2. The reactor has been employed for the methylation of carboxylic acids, the synthesis of α-chloro ketones and pyrazoles, and palladium-catalyzed cyclopropanation reactions on laboratory scale. The implementation of in-line FTIR technology allowed monitoring of the CH2N2 generation and its consumption. In addition, larger scales (1.8 g diazomethane per hour) could be obtained via parallelization (numbering up) by simply wrapping several membrane tubings into the flask.

  11. Bilateral Transverse Mandibular Second Molars: A Case Report

    Directory of Open Access Journals (Sweden)

    James Puryer

    2016-11-01

    Full Text Available Impaction of mandibular second permanent molars is a rare occurrence, with prevalence rates reported to be between 0.65% and 2.0%. In the absence of systemic conditions, impactions are usually unilateral. There appears to be no consensus as to the optimal treatment for impacted mandibular second molars and treatment plans will be based upon the individual case. Treatment may involve orthodontics and/or various surgical techniques, and early diagnosis is important. This paper presents an unusual case of bilateral transverse impaction of both mandibular second and third molars that was diagnosed at 18 years of age. All impacted molars were extracted.

  12. Distal caries of the second molar in the presence of a mandibular third molar - a prevention protocol.

    Science.gov (United States)

    Toedtling, V; Coulthard, P; Thackray, G

    2016-09-23

    Objectives The objectives of the prospective study were to establish the prevalence of distal caries (DC) in the mandibular second molar and to assess the outcomes of these diseased teeth in our population. Further aims were to identify associated risk factors and to design a protocol for prevention.Methods Clinical and radiographic data from 210 consecutive patients were ascertained over a three-month period. The sample population included all patients who had been referred to a hospital oral surgery department for a lower wisdom tooth assessment.Results A total of 224 mandibular third molars were included and assessed. The prevalence of caries affecting the distal aspect of the second molar was 38% (n = 85) in this population. In 18% of patients there was evidence of early enamel caries. Fifty-eight percent of caries was managed with restorative treatment but 11% of patients required second molar extraction and 13% of patients required the removal of the second and third molars. The prevalence of distal caries was significantly higher in patients with partially erupted wisdom teeth positioned below the amelocemental junction (P molar and in patients who presented with mesioangular impactions (P molars are useful disease predictors which can be used to indicate the likelihood of a caries process occurring on the distal aspect of the second mandibular molar. If patients' third molar teeth are not removed then consideration needs to be given to prevention and regular monitoring.

  13. Presence of third molars in orthodontic patients from northern Greece

    Directory of Open Access Journals (Sweden)

    Barka G

    2012-05-01

    Full Text Available Georgia Barka,1 Georgios Tretiakov,1 Theodosios Theodosiou,2 Ioulia Ioannidou-Marathiotou31School of Dentistry, 2Biostatistics, Department of Informatics, School of Natural Sciences, 3Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, GreeceObjective: The purpose of the present study was to investigate the frequency of presence of third molar teeth and their distribution in each jaw and each side, according to sex, in a group of orthodontic patients with permanent dentition from northern Greece.Methods: The sample included panoramic radiographs from 220 patients with permanent dentition (mean age 13.62 ± 1.81. The Χ2 test was used to assess the relationships between the variables, and the Fisher's exact test was used in cases where the expected frequencies in each cell were <5.Results: The frequency of third molar presence was 79.1%, and 20.9% was the frequency of third molar agenesis. Intersexual differences in the number of third molars was not statistically significant. There was a correlation between the distribution of third molars on the right and the left side (Fisher's exact test = 100.788; P = 0. The two sides showed the same tendency toward the presence or absence of third molars. A correlation was also found between the distribution of maxillary and mandibular third molars (Fisher's exact test = 24.372; P = 0. In each jaw, the presence or absence of third molars was highly related to the number of third molars found in the other jaw.Conclusion: The present results showed that in this orthodontic group of northern Greek patients, presence accounted for 79.1% and agenesis for 20.9%. No significant difference was found between the frequencies of third molar presence on the left and right sides in either the maxilla or mandible.Keywords: third molars, presence, orthodontic population, Greeks

  14. Enzymatic biodiesel production kinetics using co-solvent and an anhydrous medium: a strategy to improve lipase performance in a semi-continuous reactor.

    Science.gov (United States)

    Azócar, Laura; Navia, Rodrigo; Beroiz, Leticia; Jeison, David; Ciudad, Gustavo

    2014-09-25

    Enzymatic biodiesel production kinetics under previously optimized conditions were investigated. Waste frying oil (WFO) was used as the raw material, Novozym 435 as catalyst, methanol as acyl acceptor and tert-butanol as co-solvent. To investigate pure transesterification kinetics improving product properties, 3Å molecular sieves were incorporated into the reaction to provide an anhydrous medium avoiding the side reactions of hydrolysis and esterification. The effects of either WFO or methanol on the reaction rate were analyzed separately. The reaction was described by a Ping Pong mechanism and competitive inhibition by methanol. The results obtained in the kinetics study were applied in the operation of a semi-continuous reactor for biodiesel production. The operational conditions of each reaction cycle were: methanol-to-oil ratio 8/1 (mol/mol), 15% (wt) Novozym 435, 0.75% (v/v) of tert-butanol, 44.5°C, 200 rpm and 4h of reaction time. The enzymes were successively reused by remaining in the reactor during all the cycles. Under these conditions, biodiesel production yields higher than 80% over 7 reaction cycles were observed. Both the kinetics study and the reactor operation showed that Novozym 435 was not inhibited at high methanol concentrations and that the kinetics of the proposed enzymatic process could be comparable to the conventional chemical process.

  15. Optical absorption and DFT calculations in L-aspartic acid anhydrous crystals: Charge carrier effective masses point to semiconducting behavior

    Science.gov (United States)

    Silva, A. M.; Silva, B. P.; Sales, F. A. M.; Freire, V. N.; Moreira, E.; Fulco, U. L.; Albuquerque, E. L.; Maia, F. F., Jr.; Caetano, E. W. S.

    2012-11-01

    Density functional theory (DFT) computations within the local-density approximation and generalized gradient approximation in pure form and with dispersion correction (GGA+D) were carried out to investigate the structural, electronic, and optical properties of L-aspartic acid anhydrous crystals. The electronic (band structure and density of states) and optical absorption properties were used to interpret the light absorption measurements we have performed in L-aspartic acid anhydrous crystalline powder at room temperature. We show the important role of the layered spatial disposition of L-aspartic acid molecules in anhydrous L-aspartic crystals to explain the observed electronic and optical properties. There is good agreement between the GGA+D calculated and experimental lattice parameters, with (Δa, Δb, Δc) deviations of (0.029,-0.023,-0.024) (units in Å). Mulliken [J. Chem. Phys.JCPSA60021-960610.1063/1.1740588 23, 1833 (1955)] and Hirshfeld [Theor. Chim. ActaTCHAAM0040-574410.1007/BF00549096 44, 129 (1977)] population analyses were also performed to assess the degree of charge polarization in the zwitterion state of the L-aspartic acid molecules in the DFT converged crystal. The lowest-energy optical absorption peaks related to transitions between the top of the valence band and the bottom of the conduction band involve O 2p valence states and C 1p and O 2p conduction states, with the carboxyl and COOH lateral chain group contributing significantly to the energy band gap. Among the calculated band gaps, the lowest GGA+D (4.49-eV) gap is smaller than the experimental estimate of 5.02 eV, as obtained by optical absorption. Such a wide-band-gap energy together with the small carrier effective masses estimated from band curvatures allows us to suggest that an L-aspartic acid anhydrous crystal can behave as a wide-gap semiconductor. A comparison of effective masses among directions parallel and perpendicular to the L-aspartic molecules layers reveals that charge

  16. Elongational viscosity of narrow molar mass distribution polystyrene

    DEFF Research Database (Denmark)

    Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz;

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...

  17. Incomplete molar pregnancy with live coexisting fetus: a case report

    Directory of Open Access Journals (Sweden)

    Leila Pourali

    2014-03-01

    Conclusion: The rate of pregnancy complications such as hypertension, hyperthyroidism, and obstetrics hemorrhage and also the risk of Gestational Trophoblastic Neoplasm (GTN are increasing in incomplete molar pregnancy. Therefore, early diagnosis and timely treatment of molar pregnancy is very important to reduce maternal morbidity and mortality.

  18. Molar incisor hypomineralisation: clinical management of the young patient.

    LENUS (Irish Health Repository)

    Daly, Dympna

    2009-04-01

    Molar incisor hypomineralisation (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. Early diagnosis is essential since rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its clinical management in young children.

  19. Changes in heart rate during third molar surgery

    NARCIS (Netherlands)

    Hollander, M H J; Schortinghuis, J; Vissink, A

    2016-01-01

    Anxiety is an undesirable psychological phenomenon. Patients are usually anxious when subjected to third molar surgery, but the pattern of anxiety is unknown. The aim of this study was to assess the intensity and course of anxiety during third molar surgery. This study included 48 consecutive patien

  20. Possibilty of the lower third molar eruption: Radiographic analysis

    Directory of Open Access Journals (Sweden)

    Nedeljković Nenad

    2006-01-01

    Full Text Available Backgraund/Aim. To assess the possibility of the eruption of the lower third molar on the basis of the measured parameters: retromolar space, mesiodistal crown width of a molar and the third molar angulation. Methods. The investigation included 104 patients both sexes (43 boys, and 61 girls, 16 to 25 years old (meanage, 18 years. It was performed using the orthopanthomographic radiographs analysis of those patients. Each radiograph was covered by tracing paper, and the contoures of the followiny anatomic details were drawn: a the crown and root contours of third molars, upper and lower central incisors, distal molars in occlusion, anterior edge of ramus mandible, b lines: 1. the occlusal plane, 2. the line of retromolar space, 3. the mesiodistal crown width of third molar, 4. the axial shaft of the third molar and the distal angle between occlusal plane and the axial shaft of the third molar. The values were measured with an orthodontic caliper: the diameter of retromolar space, diameter of mesiodistal width, the value of distal angle between occlusal plane and axial shaft of molar. Results. A favourable angulation of the lower third molar (more than 60° was found in, boys (left 27.90%, right 32.55%, girls (left 39.34%, right 37.77%. A favourable relationship between the diameters of mesiodistal width of the third molar and retromolar space was found in, boys, (left 13.59%, right 16.27%, girls, (left 8.19%, right 14.75%. A favorable relationship between the diameters of mesiodistal width of the third molar and the retromolar space and the angulation was found in boys, (left 9.30%, right 11.62%, girls, (left 6.56%, right 9.83%. Conclusion. There was not any statistically significant difference found between the relation of the retromolar value, third molar mesiodistal diameter, or of the third molar angulation to the left and the right side nor of their mutual relations in comparing boys and girls. A favorable prognosis was found in 9.33% of the

  1. Anhydrous octyl-glucoside phase transition from lamellar to isotropic induced by electric and magnetic fields.

    Science.gov (United States)

    Hashim, Rauzah; Sugimura, Akihiko; Nguan, Hock-Seng; Rahman, Matiur; Zimmermann, Herbert

    2017-02-28

    A static deuterium nuclear magnetic resonance ((2)HNMR) technique (magnetic field, B = 7.05 T) was employed to monitor the thermotropic lamellar phase of the anhydrous 1:1 mixture sample of octyl-b-D-glucoside (βOG) and that of partially deuterium labelled at the alpha position on the chain, i.e.,βOG-d2 In the absence of an electric field, the (2)H NMR spectrum of the mixture gives a typical quadrupolar doublet representing the aligned lamellar phase. Upon heating to beyond the clearing temperature at 112 °C, this splitting converts to a single line expected for an isotropic phase. Simultaneous application of magnetic and electric fields (E = 0.4 MV/m) at 85 °C in the lamellar phase, whose direction was set to be parallel or perpendicular to the magnetic field, resulted in the change of the doublet into a single line and this recovers to the initial doublet with time for both experimental geometries. This implies E- and B-field-induced phase transitions from the lamellar to an isotropic phase and a recovery to the lamellar phase again with time. Moreover, these phase transformations are accompanied by a transient current. A similar observation was made in a computational study when an electric field was applied to a water cluster system. Increasing the field strength distorts the water cluster and weakens its hydrogen bonds leading to a structural breakdown beyond a threshold field-strength. Therefore, we suggest the observed field-induced transition is likely due to a structure change of the βOG lamellar assembly caused by the field effect and not due to Joule heating.

  2. Pulpotomies with portland cement in human primary molars

    Directory of Open Access Journals (Sweden)

    Taísa Regina Conti

    2009-02-01

    Full Text Available Two clinical cases in which Portland cement (PC was applied as a medicament after pulpotomy of mandibular primary molars in children are presented. Pulpotomy using PC was carried out in two mandibular first molars and one mandibular second molar, which were further followed-up. At the 3, 6 and 12-month follow-up appointments, clinical and radiographic examinations of the pulpotomized teeth and their periradicular area revealed that the treatments were successful in maintaining the teeth asymptomatic and preserving pulpal vitality. Additionally, the formation of a dentin bridge immediately below the PC could be observed in the three molars treated. PC may be considered as an effective alternative for primary molar pulpotomies, at least in a short-term period. Randomized clinical trials with human teeth are required in order to determine the suitability of PC before unlimited clinical use can be recommended.

  3. Management of third molar teeth from an endodontic perspective

    Directory of Open Access Journals (Sweden)

    Hany Mohamed Aly Ahmed

    2012-01-01

    Full Text Available Third molar teeth are subject to many dental complications because of their most posterior location, aberrant occlusal anatomy and abnormal eruption patterns. Owing to these anatomical limitations, their extraction remains the treatment of choice for many dental practitioners. Despite being a common dental procedure, minimum intervention and retaining every functional component of the dental arch are of prime importance in contemporary dental practice. As such, this review aims to discuss the application of this conservative approach on third molar teeth from an endodontic perspective. The internal and external root anatomy of maxillary and mandibular third molars and their relation to the surrounding vital structures are described. These anatomical landmarks are then correlated to the decision making for endodontic treatment strategies of third molars. In addition, the recommended guidelines that should be followed while commencing endodontic treatment in third molars are outlined.

  4. Extinction as discrimination: the molar view.

    Science.gov (United States)

    Baum, William M

    2012-05-01

    The traditional molecular view of behavior explains extinction as the dissipation or inhibition of strength, formerly built up by contiguous reinforcement. In obstinate opposition to this explanation was the partial-reinforcement extinction effect: a partially reinforced response extinguishes more slowly than a continuously reinforced response. It suggests instead that extinction is discrimination. Four pigeons were exposed to daily sessions in which a variable period of food delivery, produced by pecking on a variable-interval schedule, was followed by extinction. The rate of food delivery was varied over a wide range across conditions. Varying the amount of food per delivery inversely with rate of delivery kept response rate from varying excessively. The results confirmed and extended the partial-reinforcement effect; persistence of pecking and time to extinction were inversely related to rate of obtaining food. The results support the molar view of extinction, not as loss of strength of a particular discrete response, but as a transition from one allocation of time among activities to another. Although molecular theories dismiss discrimination due to repeated training and extinction as an impurity or complication, repeated cycles of availability and privation are probably typical of the environment in which most vertebrate species evolved.

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

    NARCIS (Netherlands)

    Livas, C.; Halazonetis, D.J.; Booij, J.W.; Katsaros, C.

    2011-01-01

    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 gr

  6. Phytate, calcium, iron, and zinc contents and their molar ratios in foods commonly consumed in China

    NARCIS (Netherlands)

    Ma, Guansheng; Jin, Ying; Piao, Jianhua; Kok, F.J.; Bonnema, A.B.; Jacobsen, E.

    2005-01-01

    A total of 60 food samples commonly consumed in China were analyzed for phytate using the anion-exchange method and for calcium, iron, and zinc using atomic absorption spectrophotometry. The foods analyzed included those based on cereal grains and soybean. Phytate contents expressed on a wet weight

  7. Response of molars and non-molars to a strict supragingival control in periodontal patients

    Directory of Open Access Journals (Sweden)

    Patrícia Daniela Melchiors Angst

    2013-02-01

    Full Text Available The posterior position in the arches is one of the factors that underlies the poor prognosis of molar teeth (M. It is speculated that M do not benefit from the oral hygiene routine as well as non-molars (NM do. This study evaluated the response of M and NM to supragingival control during a 6-month period in 25 smokers (S and 25 never-smokers (NS with moderate-to-severe periodontitis. One calibrated examiner assessed visible plaque (VPI and gingival bleeding (GBI indexes, periodontal probing depth (PPD, bleeding on probing (BOP, and clinical attachment loss (CAL at days 0 (baseline, 30 and 180. At baseline, M showed significantly higher mean values of VPI (p = 0.017 and PPD (p < 0.001 compared with NM; CAL was also greater in M (p < 0.001 and was affected by smoking (p = 0.007. The reductions obtained for periodontal indicators at day 180 showed similar responses between M and NM. For CAL, M (NS 0.57 ± 0.50; S 0.67 ± 0.64 and NM (NS 0.38 ± 0.23; S 0.50 ± 0.33 reached an almost significant difference (p = 0.05. Smoking did not influence the response to treatment. Multilevel analysis revealed that, only for PDD reductions, the interaction between sites, teeth and patient was significant (p < 0.001. It was concluded that M benefit from an adequate regimen of supragingival biofilm control; therefore, supragingival condition should be considered in the prognosis of molar teeth.

  8. Human third molars development: Comparison of 9 country specific populations.

    Science.gov (United States)

    Thevissen, P W; Fieuws, S; Willems, G

    2010-09-10

    The majority of age estimation models based on third molar development are constructed on samples from populations with described and outlined origin. Due to unlike research protocols these studies can rarely be compared for the evaluation of possible geographical or ethnical influences on third molar development. The aim of this study is to evaluate country specific third molar development on standardized collected and analyzed data. On panoramic radiographs selected from subjects out of 9 country specific populations (Belgium, China, Japan, Korea, Poland, Thailand, Turkey, Saudi-Arabia and South-India) the four third molar scores were registered, according to a modified Gleiser and Hunt methodology. To obtain for each subject a (factor) score which represents the degree of third molar development, a generalized linear mixed model for multivariate ordinal data was fitted on the repeated third molar scores. Differences between countries are analyzed using gender-specific regression models for these factor scores with age and country as predictors. Comparisons between countries revealed differences in speed and onset of development. However, although reaching statistical significance, differences in actual value were small and not constant over the considered age range. In all countries, at all ages, males were ahead in third molar development compared to females.

  9. Economic and health implications of routine CBCT examination before surgical removal of the mandibular third molar in the Danish population

    DEFF Research Database (Denmark)

    Petersen, L B; Rose Olsen, Kim; Matzen, L H;

    2015-01-01

    OBJECTIVES: This epidemiological study aimed to analyse economical and societal consequences in Denmark if CBCT is used routinely as a diagnostic method before removal of the mandibular third molar. Furthermore, the aim was to calculate the excess cancer incidence from this practice. METHODS: 17...... third molars in the selected clinics in the region times the ratio of the number of patients in the selected clinics in the region to the total number of patients with contact to a general practitioner in the region in 2011. Existing knowledge on the costs for panoramic and CBCT imaging was used...... annual number of removed mandibular third molars of 36,882 at a total cost of €6,633,400. The additional cancer incidence was estimated to be approximately 0.46 per year. CONCLUSIONS: The data should be used in a cost-effectiveness analysis of the clinical efficacy of CBCT imaging before removal...

  10. Molar Pregnancy with a Co-Existing Viable Fetus

    Directory of Open Access Journals (Sweden)

    Ruya Deveer

    2014-03-01

    Full Text Available     The aim of this study was to report the clinical features, management, and outcome of a case of molar pregnancy with a coexisting viable fetus and to review the literature. In this article, we report a case of pregnancy with diffuse placental molar change and a normal fetus which presented with hyperemesis gravidarum and hyperthyroidism. Genetic amniocentesis showed normal fetal karyotype. A healthy full-term live male infant was delivered by cesarean section. In molar pregnancies with a normal karyotype fetus, with intensive maternal follow-up, continuation of pregnancy can be suggested.

  11. Management of a Severely Submerged Primary Molar: A Case Report

    Directory of Open Access Journals (Sweden)

    Iman Parisay

    2013-01-01

    Full Text Available Ankylosis is a condition frequently associated with primary molars, wherein the ankylosed primary teeth remain in a fixed position, while the adjacent teeth continue to erupt, moving occlusally. In this case report, a five-year-old boy, who had a retained and submerged left lower second primary molar, was presented. Luxation of ankylosed primary molar was considered as a treatment approach. After four months, the tooth erupted to the occlusal level, and there was evidence of further development of a permanent successor in radiographic evaluation. After one year, tooth mobility, bone formation, and development of a permanent successor were in good condition.

  12. Prevalence and severity of molar incisor hypomineralization in children aged 11-16 years of a city in Karnataka, Davangere

    Directory of Open Access Journals (Sweden)

    M Kirthiga

    2015-01-01

    Full Text Available Introduction: Molar incisor hypomineralization (MIH describes the clinical picture of hypomineralization of systemic origin affecting one or more first permanent molar. There is a rarity of prevalence studies in Indian population. Objectives: The main aim of this study was to investigate the prevalence of MIH in a population of South Indian children. Settings and Design: A cross-sectional epidemiological survey, included 2000 children aged 11-16 years chosen by stratified random sampling from government and private schools of Davangere, a city in South India. Materials and Methods: Evaluation of MIH and decayed, missing and filled teeth was carried out in these children by a calibrated examiner. The severity of hypomineralization was recorded according to the Wetzel and Reckel scale. Statistical Analysis: Chi-square test was used to analyze the categorical data. P ≤ 0.05 was considered for statistical significance. Results: About 8.9% of all examined children showed at least one ill-structured first permanent molar in terms of MIH. The male and female ratio was found to be 1:1.1. The decreasing order of occurrence of MIH affected teeth were permanent maxillary molars, maxillaryincisors, mandibular molars and the mandibular incisors. Conclusion: The prevalence of MIH in the permanent dentition of south Indian children was 8.9%. There is a need for a proper planned preventive and restorative program with regard to the increasing prevalence of MIH.

  13. In vitro study on the interaction of ketotifen fumarate with anhydrous theophylline

    Directory of Open Access Journals (Sweden)

    Mohammed Aktar Sayeed

    2012-06-01

    Full Text Available The purpose of the present study was to investigate the interaction between ketotifen fumarate and anhydrous theophylline in aqueous media of various pH (1.2 and 6.8. Using Job's continuous-variation analysis and Ardon's spectrophotomeric measurement methods, the values of the stability constants of theophylline with ketotifen were determined at a fixed temperature (37 ºC at various pH. The stability constants, ranging between 5.66 and 9.92, were derived from Ardon's plot, indicating that comparatively stable complexes had formed as a result of an interaction between the drugs. However, following the interaction of theophylline with ketotifen, stability constants were O objetivo do presente estudo foi investigar a interação entre o fumarato de cetotifeno e a teofilina anidra em meios aquosos com vários pH (1,2 e 6,8. Utilizando a análise da variação contínua de Job e os métodos de medida espectrofotométrica de Ardon, os valores das constantes de estabilidade da teofilina com o cetotifeno foram determinados em temperatura fixa (37 oC em vários pH. As constantes de estabilidade, variando entre 5,66 e 9,92 derivaram-se a partir do delineamento de Ardon, indicando, comparativamente, que complexos estáveis se formaram como resultado da interação entre os fármacos. Entretanto, seguindo a interação da teofilina com o cetotifeno, as constantes de estabilidade foram <1, em pH gástrico (1,2 e intestinal (8,8. A administração concomitante de cetotifeno e teofilina poderia resultar na formação de complexo estável, o que reduz a atividade terapêutica de ambos os fármacos.

  14. Hipomineralização molar-incisivo = Molar incisor hypomineralization

    Directory of Open Access Journals (Sweden)

    Basso, Ana Paula

    2007-01-01

    Full Text Available A hipomineralização-molar incisivo (HMI é um defeito de origem sistêmica no esmalte dentário de primeiros molares e incisivos permanentes. Nesta condição, o esmalte hipomineralizado é frágil e pode se destacar facilmente, deixando a dentina exposta e causando, assim, problemas como sensibilidade dentária e maior risco ao estabelecimento de lesões de cárie. A HMI é freqüentemente confundida com fluorose ou amelogênese imperfeita e sua prevalência varia de 3,6 a 25%. Vários fatores etiológicos são citados para a condição e estão freqüentemente relacionados com doenças na infância nos primeiros três anos de vida. O tratamento envolve desde a restauração dos dentes afetados com materiais adesivos ou até mesmo a extração dos mesmos, dependendo da severidade do caso

  15. An assessment on the effects of mandibular impacted third molar surgery on the periodontium of the adjacent molar

    Directory of Open Access Journals (Sweden)

    Ramezanian M

    2003-06-01

    Full Text Available Statement of Problem: One of the important indications for the extraction of mandibular impacted third"nmolar is to preserve the periodontal health of the adjacent second molar from the destructive effects of"nplaque accumulation, acute and chronic inflammation."nAim: The purpose of this study was to determine the effect of mandibular third molar surgery on the"nPDL of the adjacent molar."nMaterials and Methods: Thirty patients, referred to the department of maxillofacial surgery, Tehran"nUniversity of Medical Sciences, were selected, based on the desirable conditions. They had no history of"nsystemic diseases and their adjacent molar was healthy. Probing depth (PD at seven points and"nattachment level (AL at three points were measured preoperatively. Standardized periapical"nradiographics were taken regularly for all patients. All the above-mentioned procedures repeated after"nthree months of surgery. Findings were analyzed by Paired t-test."nResults: A significant difference in probing depth (PD was observed before and after surgery, meaning"nthat probing depth decreased after mandibular third molar surgery. Attachment level was also decreased"npost operatively; moreover. Intrabony defects (IBD showed healing after surgery."nConclusion: Considering the limitations of the present study, impacted third molar surgery is suggested"nto prevent periodontal problems of the adjacent molar.

  16. Improved quantification of alite and belite in anhydrous Portland cements by 29Si MAS NMR: Effects of paramagnetic ions

    DEFF Research Database (Denmark)

    Poulsen, Søren Lundsted; Kocaba, Vanessa; Le Saoût, Gwenn;

    2009-01-01

    The applicability, reliability, and repeatability of 29Si MAS NMR for determination of the quantities of alite (Ca3SiO5) and belite (Ca2SiO4) in anhydrous Portland cement was investigated in detail for 11 commercial Portland cements and the results compared with phase quantifications based...... on powder X-ray diffraction combined with Rietveld analysis and with Taylor-Bogue calculations. The effects from paramagnetic ions (Fe3+) on the spinning sideband intensities, originating from dipolar couplings between 29Si and the spins of the paramagnetic electrons, were considered and analyzed in spectra...

  17. Special topical approach to the treatment of acne. Suppression of sweating with aluminum chloride in an anhydrous formulation.

    Science.gov (United States)

    Hurley, H J; Shelley, W B

    1978-12-01

    A new topical approach to acne treatment--the use of aluminum chloride hexahydrate in anhydrous ethanol (ACAE)--was studied in 141 patients. Using sequential treatment schedules, paired comparison techniques, and various concentrations of ACAE, we established maximal efficacy with minimal local irritation for the 6.25% strength solution. Clinical efficacy and lack of toxicity of this formulation were confirmed by the additional clinical study of 65 patients. The antiperspirant and antibacterial actions of 6.25% ACAE solution were then verified on acne skin areas. It is postulated that the clinical improvement in acne that follows the topical use of ACAE results from one or both of these actions.

  18. A Safe and Brief Way for Preparing Anhydrous LnCl3 (Ln=Sc, Y, La to Lu)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Anhydrous lanthanide chlorides LnCl3 (Ln=Sc, Y, La to Lu except for Pm), which are difficult to prepare in other ways, were prepared by chemical vapor transport (CVT) process. Rare earth oxide reacted with Al2Cl6 at 300℃ to produce LnCl3, which was then separated from other solids by means of CVT at a temperature gradient from 400 to 180℃. Residual Al2Cl6 (g) was removed by carrier of dry N2 gas at 200℃. The yielding rates were >90%, and the purity of products was >99.5%.

  19. THE DEBATE ON THE ORIGIN OF MOLAR-TOOTH STRUCTURES%Molar-Tooth构造成因争论分析

    Institute of Scientific and Technical Information of China (English)

    陈永红

    2006-01-01

    综述了Molar-Tooth的时空分布及其形态特征,Molar-Tooth为元古代时期全球性的一种构造现象.其成因,地质学家们已争论了一个多世纪,直到今天还未取得一致的认识.归纳前人的研究成果,初步认为Molar-Tooth的成因与藻类等生物活动有关.

  20. Excess Molar Volume of Binary Systems Containing Mesitylene

    Directory of Open Access Journals (Sweden)

    Morávková, L.

    2013-05-01

    Full Text Available This paper presents a review of density measurements for binary systems containing 1,3,5-trimethylbenzene (mesitylene with a variety of organic compounds at atmospheric pressure. Literature data of the binary systems were divided into nine basic groups by the type of contained organic compound with mesitylene. The excess molar volumes calculated from the experimental density values have been compared with literature data. Densities were measured by a few experimental methods, namely using a pycnometer, a dilatometer or a commercial apparatus. The overview of the experimental data and shape of the excess molar volume curve versus mole fraction is presented in this paper. The excess molar volumes were correlated by Redlich–Kister equation. The standard deviations for fitting of excess molar volume versus mole fraction are compared. Found literature data cover a huge temperature range from (288.15 to 343.15 K.

  1. Cementoblastoma Relating to Right Mandibular Second Primary Molar

    Science.gov (United States)

    Manepalli, Swapna; Mohapatra, Abinash

    2016-01-01

    Cementoblastoma is a benign lesion of the odontogenic ectomesenchymal origin. It rarely occurs in primary dentition. This report describes a case of a cementoblastoma relating to the right mandibular second primary molar in a 7-year-old girl. Her panoramic radiograph revealed a well-defined radiopaque lesion with a radiolucent border extending from the distal surface of the mandibular right first primary molar to the distal surface of mandibular second primary molar. The tumor was attached to the mesial root of primary second molar and was excised along with the teeth involved and sent for histopathological evaluation, which showed irregular trabeculae of mineralized tissue interspersed with fibrovascular connective tissue, trabeculae of mineralized tissue with prominent reversal lines, and peripheral rimming of the mineralized tissue with blast cells. On a six-month follow-up, there has been no recurrence of the lesion. PMID:27738532

  2. Prediction of postoperative pain after mandibular third molar surgery

    DEFF Research Database (Denmark)

    Rudin, Asa; Eriksson, Lars; Liedholm, Rolf;

    2010-01-01

    To evaluate the predictive potential of preoperative psychological and psychophysiological variables in estimating severity of postoperative pain following mandibular third molar surgery (MTMS). Methods: Following ethical committee approval and informed consent, 40 consecutive patients scheduled...

  3. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans.

    OpenAIRE

    Shen, B.; Dong, L.; S. Xiao; Lang, X; K. Huang; Peng, Y.; C. Zhou; Ke, S; Liu, P

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (∼2,500-750 million years ago, Ma) subtidal successions, but extremely rare in rocks

  4. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans

    OpenAIRE

    Shen, Bing; Dong, Lin; Xiao, Shuhai; Lang, Xianguo; Huang, Kangjun; Peng, Yongbo; Zhou, Chuanming; Ke, Shan; Liu, Pengju

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (∼2,500–750 million years ago, Ma) subtidal successions, but extremely rare in rocks

  5. Prediction of postoperative pain after mandibular third molar surgery

    DEFF Research Database (Denmark)

    Rudin, Asa; Eriksson, Lars; Liedholm, Rolf

    2010-01-01

    To evaluate the predictive potential of preoperative psychological and psychophysiological variables in estimating severity of postoperative pain following mandibular third molar surgery (MTMS). Methods: Following ethical committee approval and informed consent, 40 consecutive patients scheduled ...

  6. On the Etiology of Molar-Incisor Hypomineralization.

    Science.gov (United States)

    Vieira, Alexandre R; Kup, Elaine

    Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Reports on the etiology of the condition and possible risk factors are inconclusive and the original suggestion that MIH is an idiopathic condition is often cited. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. In this report, we provide a rationale to explain the preferential affection of molars and incisors. We suggest that MIH is a genetic condition based on its prevalence, which varies depending on the geographic location, and the evidence that on occasion second primary molars, permanent canines, and premolars can show signs of hypomineralization of enamel when molars and incisors are affected.

  7. Molar incisor hypomineralization (MIH): clinical presentation, aetiology and management.

    Science.gov (United States)

    Weerheijm, K L

    2004-01-01

    In this paper, the current knowledge about Molar Incisor Hypomineralization (MIH) is presented. MIH is defined as hypomineralization of systemic origin of one to four permanent first molars frequently associated with affected incisors and these molars are related to major clinical problems in severe cases. At the moment, only limited data are available to describe the magnitude of the phenomenon. The prevalence of MIH in the different studies ranges from 3.6-25% and seems to differ in certain regions and birth cohorts. Several aetiological factors (for example, frequent childhood diseases) are mentioned as the cause of the defect. Children at risk should be monitored very carefully during the period of eruption of their first permanent molars. Treatment planning should consider the long-term prognosis of these teeth.

  8. The orthodontic extraction of permanent molars: a literature review.

    Science.gov (United States)

    Chua, Emilia S L; Felicita, A Sumathi

    2015-05-01

    The most common cause of dental crowding is the presence of an arch-length--tooth-size discrepancy. Conventional methods of gaining space in orthodontics involve the extraction of teeth, often premolars. However, there are a number of clinical situations in which the extraction of permanent molars might be considered. This paper highlights the indications, advantages, disadvantages and timing of the extraction of the first, second and third permanent molars in the treatment of a crowded malocclusion.

  9. Iatrogenic Mandibular Fracture Associated with Third Molar Removal

    Directory of Open Access Journals (Sweden)

    Abdulkadir Burak Cankaya, Mehmet Ali Erdem, Sirmahan Cakarer, Muhsin Cifter, Cuneyt Korhan Oral

    2011-01-01

    Full Text Available Third molar extraction is one of the most common procedures performed in oral and maxillofacial surgery units. It is sometimes accompanied by complications such as alveolar osteitis, secondary infection, hemorrhage, dysesthesia and, most severely, iatrogenic fracture. This article describes two mandibular angle fractures that occurred in two patients during the surgical extraction of one erupted and one unerupted third molar, including a brief review of the literature.

  10. Iatrogenic Mandibular Fracture Associated with Third Molar Removal

    OpenAIRE

    Abdulkadir Burak Cankaya, Mehmet Ali Erdem, Sabri Cemil Isler, Sabit Demircan, Merva Soluk, Cetin Kasapoglu, Cuneyt Korhan Oral

    2011-01-01

    Third molar extraction is one of the most common procedures performed in oral and maxillofacial surgery units. It is sometimes accompanied by complications such as alveolar osteitis, secondary infection, hemorrhage, dysesthesia and, most severely, iatrogenic fracture. This article describes two mandibular angle fractures that occurred in two patients during the surgical extraction of one erupted and one unerupted third molar, including a brief review of the literature.

  11. COMPLICATIONS AFTER EXTRACTION OF IMPACTED THIRD MOLARS - LITERATURE REVIEW

    OpenAIRE

    Elitsa G. Deliverska; Milena Petkova

    2016-01-01

    Third molar surgery is the most common procedure performed by oral and maxillofacial surgeons worldwide. This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Complications, such as pain, dry socket, swelling, paresthesia of the lingual or inferior alveolar nerve, bleeding, and infection are most common. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical hi...

  12. Use of sevoflurane inhalation sedation for outpatient third molar surgery.

    OpenAIRE

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

    1999-01-01

    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 subj...

  13. Fusion or gemination? An unusual mandibular second molar

    Directory of Open Access Journals (Sweden)

    Angela Jordão Camargo

    2016-01-01

    Full Text Available Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving “second and third” molar.

  14. Evaluation of diagnostic accuracy and dimensional measurements by using CBCT in mandibular first molars

    Science.gov (United States)

    Asgary, Saeed; Nikneshan, Sima; Akbarzadeh-Bagheban, Alireza

    2016-01-01

    Background This study aimed to assess the diagnostic accuracy of cone beam computed tomography (CBCT) and quantitatively evaluate the morphology of mandibular first molars using CBCT. Material and Methods Twenty-four double-rooted mandibular first molars were evaluated by NewTom VGi CBCT. The distance from the furcation and apex to the cementoenamel junction (CEJ), diameter and thickness of canal walls, the buccolingual (BL) to mesiodistal (MD) ratio (ΔD), prevalence of oval canals at different sections and taper of the canals were all determined. In order to assess the diagnostic accuracy of CBCT, distance from the furcation and apex to the CEJ and thickness of canal walls at the CEJ and apex were compared with the gold standard values (caliper and stereomicroscope). Statistical analyses were carried out using intraclass correlation coefficient (ICC), paired t-test and repeated measures ANOVA. Results A high correlation existed between the CBCT and gold standard measurements (Pmeasurements, length of mesial root was higher than the distal root and lingual furcation was farther from the CEJ than the buccal furcation (Paccuracy for measurement of canal wall thickness. Cleaning and shaping of the canals should be performed based on the unique anatomy of the respective canal; which necessitates the use of advanced imaging techniques for thorough assessment of root canal anatomy in a clinical setting. Key words:Permanent mandibular first molar, accuracy, cone-beam computed tomography, dimensional measurement. PMID:26855697

  15. Outcome of Subsequent Pregnancies in Familial Molar Pregnancy

    Directory of Open Access Journals (Sweden)

    Masoumeh Fallahian

    2013-01-01

    Full Text Available Familial recurrent molar pregnancy is an exceedingly rare condition, in which completehydatidiform moles are mostly diploid but biparental in origin and the outcome of subsequentpregnancies is likely to be a hydatidiform mole or other type of reproductiveloss. We previously reported a case of familial molar pregnancy (family K comprisingfive affected members (four sisters and one of their cousins each with at least one hydatidiformmole (HM. In addition to the molar pregnancies, these patients have a total ofthree miscarriages and 8 normal pregnancies leading to healthy children; but the youngestmember of this family has given birth to a boy with Down syndrome.Our second family (case S includes two sisters with diploid biparental complete moles.They have a total of six molar pregnancies with no living child. Recently the younger sisterhad a partial molar pregnancy with apparently normal XX fetus accompanying diffusemolar changes of the placenta that led to preeclampsia and preterm delivery.Overall, these families have had 26 pregnancies including 12 molar pregnancies (completeor partial and three abortions.We concluded that these families are predisposed to various genetic mutations, chromosomalabnormalities and clinical manifestations, which affect their offspring. Furtherstudies of patients are needed to determine any relationship between a history of familialmolar pregnancy and trisomy or other chromosomal abnormalities in offspring and geneticmutations in the products of conception to complete the puzzle and manage familialmolar pregnancy.

  16. Aspartic acid racemization in dentin of the third molar for age estimation of the Chaoshan population in South China.

    Science.gov (United States)

    Chen, Shisheng; Lv, Yanyi; Wang, Dian; Yu, Xiaojun

    2016-09-01

    Aspartic acid racemization in teeth has been increasingly used to estimate chronological age with a considerably high accuracy in forensic practice. The Chaoshan population in South China is relatively isolated in geography, and has specific lifestyle and dietary inhibits. It is still unknown whether this method is suitable for this population. The aim of this study was to analyze the relationship between chronological age and the d/l aspartic acid ratio in dentin in the third molar tooth of the Chaoshan population. Fifty-eight non-carious third molar teeth (31 mandibles and 27 maxillae), from 58 living individuals of known age (24 males and 34 females), were retrieved. Dentin was extracted from these teeth. The d- and l-aspartic acids in dentins were separated and detected by high performance liquid chromatography (HPLC). Linear regression was performed between the d/l aspartic acid ratio of dentins and chronological age. Results showed that the correlation coefficient (r) was 0.969, and the mean absolute error (MAE) was 2.19 years, its standard deviation (SD) was ±1.53 years, indicating excellent correlation. There was no significant difference in racemization rates of dentin between sexes (P=0.113, F=2.6), or between mandibles and maxillae (P=0.964, F=0.000). Results indicate that the ratio of the d and l forms of aspartic acid of dentins, in the third molar, is closely correlated with chronological age, special lifestyle do no obviously affect the accuracy of the age estimations by aspartic acid racemization of the dentin in the third molar and that aspartic acid racemization in the third molar dentin can be used as an accurate method to estimate chronological age in the Chaoshan population in South China.

  17. Ionic-liquid-based proton conducting membranes for anhydrous H2/Cl2 fuel-cell applications.

    Science.gov (United States)

    Liu, Sa; Zhou, Li; Wang, Pengjie; Zhang, Fangfang; Yu, Shuchun; Shao, Zhigang; Yi, Baolian

    2014-03-12

    An ionic-liquid-doped poly(benzimidazole) (PBI) proton-conducting membrane for an anhydrous H2/Cl2 fuel cell has been proposed. Compared with other ionic liquids, such as imidazole-type ionic liquids, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) showed better electrode reaction kinetics (H2 oxidation and Cl2 reduction reaction at platinum) and was more suitable for a H2/Cl2 fuel cell. PBI polymer and [dema][TfO] were compatible with each other, and the hybrid membranes exhibited high stability and good ionic conductivity, reaching 20.73 mS cm(-1) at 160 °C. We also analyzed the proton-transfer mechanism in this ionic-liquid-based membrane and considered that both proton-hopping and diffusion mechanisms existed. In addition, this composite electrolyte worked well in a H2/Cl2 fuel cell under non-water conditions. This work would give a good path to study the novel membranes for anhydrous H2/Cl2 fuel-cell application.

  18. Measurement of bonding energy in an anhydrous nitrogen atmosphere and its application to silicon direct bonding technology

    Science.gov (United States)

    Fournel, F.; Continni, L.; Morales, C.; Da Fonseca, J.; Moriceau, H.; Rieutord, F.; Barthelemy, A.; Radu, I.

    2012-05-01

    Bonding energy represents an important parameter for direct bonding applications as well as for the elaboration of physical mechanisms at bonding interfaces. Measurement of bonding energy using double cantilever beam (DCB) under prescribed displacement is the most used technique thanks to its simplicity. The measurements are typically done in standard atmosphere with relative humidity above 30%. Therefore, the obtained bonding energies are strongly impacted by the water stress corrosion at the bonding interfaces. This paper presents measurements of bonding energies of directly bonded silicon wafers under anhydrous nitrogen conditions in order to prevent the water stress corrosion effect. It is shown that the measurements under anhydrous nitrogen conditions (less than 0.2 ppm of water in nitrogen) lead to high stable debonding lengths under static load and to higher bonding energies compared to the values measured under standard ambient conditions. Moreover, the bonding energies of Si/SiO2 or SiO2/SiO2 bonding interfaces are measured overall the classical post bond annealing temperature range. These new results allow to revisit the reported bonding mechanisms and to highlight physical and chemical phenomena in the absence of stress corrosion effect.

  19. Effect of increasing the protein-to-fat ratio and reducing fat content on the chemical and physical properties of processed cheese product.

    Science.gov (United States)

    Guinee, T P; O'Callaghan, D J

    2013-01-01

    Scientific studies indicate that the intake of dietary fat and saturated fats in the modern Western diet is excessive and contributes adversely to health, lifestyle, and longevity. In response, manufacturers of cheese and processed cheese products (PCP) are pursuing the development of products with reduced fat contents. The present study investigated the effect of altering the fat level (13.8, 18.2, 22.7, 27.9, and 32.5 g/100g) in PCP on their chemical and physical properties. The PCP were formulated in triplicate to different fat levels using Cheddar cheese, skim milk cheese, anhydrous milk fat, emulsifying salt (ES), NaCl, and water. The formulations were designed to give fixed moisture (~53 g/100g) and ES:protein ratio (0.105). The resultant PCP, and their water-soluble extracts (WSE), prepared from a macerated blend of PCP and water at a weight ratio of 1:2, were analyzed at 4d. Reducing the fat content significantly increased the firmness of the unheated PCP and reduced the flowability and maximum loss tangent (fluidity) of the melted PCP. These changes coincided with increases in the levels of total protein, water-soluble protein, water-insoluble protein, and water-soluble Ca, and a decrease in the molar ratio of water-soluble Ca to soluble P. However, both water-soluble Ca and water-soluble protein decreased when expressed as percentages of total protein and total Ca, respectively, in the PCP. The high level of protein was a major factor contributing to the deterioration in physical properties as the fat content of PCP was reduced. Diluting the protein content or reducing the potential of the protein to aggregate, and thereby form structures that contribute to rigidity, may provide a means for improving quality of reduced-fat PCP by using natural cheese with lower intact casein content and lower calcium:casein ratio, for example, or by decreasing the ratio of sodium phosphate to sodium citrate-based ES.

  20. Variation in Cuspal Morphology in Maxillary First Permanent Molar with Report of 3 Cusp Molar- A Prevalence Study

    Science.gov (United States)

    2016-01-01

    Introduction Human teeth has always been known for morphological variations in both the crown and root structures. The corono-morphological variations can be in the form of extra cusp or missing cusp. Permanent maxillary first molars are the biggest teeth in maxillary arch and have a high anchorage value and are known for their four cusp and five cusp patterns, if present with cusp of Carebelli. Aim The aim of this study was to determine the prevalence of cuspal variations and quantification of cusps of permanent maxillary first molar in Malwa population. Materials and Methods A total of 1249 individuals were studied at Government College of Dentistry, Indore, Madhya Pradesh, India, to evaluate the number of cusps in permanent maxillary first molars. Results Of the studied 1249 individuals, permanent maxillary first molars had five cusps in 407 (32.6%) cases while 838 (67.08%) cases had four cusp and four (0.32%) cases had three cusps. The four cases having three cusp permanent maxillary first molars were present unilaterally and only in females. Conclusion This article emphasizes the presence of permanent maxillary first molar with only three cusps in the Malwa population of India. It also reviews the literature in respect to this rare anomaly and calls for continuous and close monitoring to report such cases in the future. PMID:27790576

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

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yansan (Korea, Republic of)

    2013-12-15

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

  2. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2005-12-15

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.

  3. Erupted complex odontoma delayed eruption of permanent molar.

    Science.gov (United States)

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier.

  4. Iatrogenic displacement of impacted third molar. Case report

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    Konstantinos TSIKLAKIS

    2013-08-01

    Full Text Available Peri-operative complications may occur during the surgical extraction of impacted mandibular third molars such as the iatrogenic displacement of the whole tooth or a tooth fragment in to the adjacent anatomical structures. The purpose of this case report is to present the diagnosis and treatment planning, as well as the surgical management required for the removal of a 3rd molar displaced in the soft tissues of the floor of the mouth. A 38-year old male patient presented to the Dental School, complaining of pain around the left submandibular area that started three months after the extraction of the impacted mandibular left third molar. At the radiographic examination the tooth was detected in the soft tissues of the floor of the mouth and in close proximity to the lingual plate. It is noteworthy that the patient was under the assumption that the tooth had been extracted successfully. Radiographically the tooth appeared at an 180° turnaround from its original position. Surgical extraction of the displaced third molar took place under local anaesthesia. No post-operative complications were reported. Thorough clinical and radiographic examination, as well as competency at surgical procedures are prerequisites for the appropriate surgical management of impacted third molars.

  5. Uterine rupture following incomplete molar pregnancy: a case report

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    Pourali L

    2013-03-01

    Full Text Available Background: In molar pregnancy, when hydatidiform changes are local and some embryonic components are observed, the term of partial mole is used. The risk of persistent trophoblastic tumor after partial mole is much lower than complete mole. In this persistent cases almost all are non metastatic. The aim of this study is to report a case of uterine rupture following incomplete molar pregnancy.Case presentation: The patient was a 26 year old woman with obstetric history of an abortion and one molar pregnancy and no child. She was referred to emergency unit in Ghaem University Hospital, Mashhad, Iran in May 2011. She had an evacuation curettage following molar pregnancy three months before and without any follow up visit. The patient was referred to emergency unit with hemorrhagic shock. She immediately underwent laparotomy. The uterine fundal rupture was repaired and evacuation curettage performed. In post operative evaluation, she had a nine millimeter metastatic nodule in base of right Lung. As a patient in low risk stage III, she received weekly intramuscular methotrexate (40mg/m2 for six courses. In follow up visit -hCG titer was negative (<10miu/ml at 5th week. Conclusion: In cases of in complete molar pregnancy risk of metastasis is very low. Serial beta-hCG titer is the most accurate method for detection of persistent gestational trophoblastic disease (GTN. In neglected cases like this case preservation of ruptured uterus in GTN is possible.

  6. In situ XRD Study of Ca2+ Saturated Montmorillonite (STX-1) Exposed to Anhydrous and Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Schaef, Herbert T.; Ilton, Eugene S.; Qafoku, Odeta; Martin, Paul F.; Felmy, Andrew R.; Rosso, Kevin M.

    2012-01-09

    Reactions involving scCO2 and a calcium saturated dioctahedral smectite (Ca-STX-1) were examined by in situ high-pressure x-ray diffraction over a range of temperatures (50° to 100°C) and pressures (90, 125, and 180 bar) relevant to long term geologic storage of CO2. Exposure of Ca-STX-1 containing one water of hydration (1W) to anhydrous scCO2 at 50°C and 90 bar produced an immediate increase of ~0.8 Å in the d001 basal reflection that was sustained for the length of the experiment (~44 hours). Higher ordered basal reflections displayed similar shifts. Following depressurization, positions of basal reflections and FWHM values (d001) returned to initial values, with no measurable modification to the clay structure or water content. Similar results were obtained for tests conducted at 50°C and higher pressures (125 and 180 bar). Exposure of Ca-STX-1 containing two waters of hydration (2W) to scCO2 resulted in a decrease in the d001 reflection from 14.48 Å to 12.52 Å, after pressurization, indicating a partial loss of interlayer water. In addition, the hydration state of the clay became more homogeneous during contact with anhydrous scCO2 and after depressurization. In the presence of scCO2 and water, the clay achieved a 3W hydration state, based on a d001 spacing of 18.8 Å. In contrast to scCO2, comparable testing with N2 gas indicated trivial changes in the d001 series regardless of hydration state (1W or 2W). In the presence of free water and N2, the basal spacing for the Ca-STX-1 expanded slightly, but remained in the 2W hydration state. These experiments indicate that scCO2 can intercalate hydrated clays, where the 1W hydrate state is stable when exposed to anhydrous scCO2 under conditions proposed for geologic storage of CO2. Consequently, clays can act as secondary CO2 traps where potential collapse or expansion of the interlayer spacing depends on the initial hydration state of the clay and scCO2.

  7. Pendulum Therapy of Molar Distalization in Mixed Dentition.

    Science.gov (United States)

    Patil, Raju Umaji; Prakash, Amit; Agarwal, Anshu

    2016-01-01

    Early and timely pedo-orthodontic treatment is aimed at eliminating the disturbances of skeletal or dentoalveolar development, to harmonize the stomatognathic system before the full eruption of all permanent teeth. The advantages of pendulum appliance are its minimal dependence on patient's compliance (child cooperation), ease of fabrication, onetime activation and adjustment of the springs if necessary to correct minor transverse and vertical molar positions. This article reports a successful treatment method of class II malocclusion with pendulum appliance in mixed dentition phase. Distalization of maxillary molar was done, followed by guidance of canine impaction orthodontically and other dental correction using 0.022 MBT appliances. Posttreatment results were stable and remarkable. How to cite this article: Patil RU, Prakash A, Agarwal A. Pendulum Therapy of Molar Distalization in Mixed Dentition. Int J Clin Pediatr Dent 2016;9(1):67-73.

  8. First permanent molar root development arrest associated with compound odontoma.

    Science.gov (United States)

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

    2013-07-04

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

  9. Microbiology of the pericoronal pouch in mandibular third molar pericoronitis.

    Science.gov (United States)

    Leung, W K; Theilade, E; Comfort, M B; Lim, P L

    1993-10-01

    The microorganisms associated with mandibular third molar pericoronitis were investigated using direct microscopy and anaerobic culture method. The pericoronal pouch was sampled with paper points in A) 8 patients without mandibular third molar pericoronitis and B) 6 patients with mandibular third molar pericoronitis. Under the microscope, the microflora was found to be a complex mixture comprising gram-positive and gram-negative cocci, rods and filaments (including fusiform and curved rods), motile rods and spirochetes. Significantly higher proportions of motile, gram-negative rods were found in group B than in group A. The predominant cultivable microflora of 9 samples: A (4) and B (5) comprised several species of facultative and obligate anaerobic bacteria, namely Peptostreptococcus, Streptococcus, Actinomyces, Eubacterium, Propionibacterium, Veillonella, Porphyromonas, Prevotella, Bacteriodes, Fusobacterium, Campylobacter, Staphylococcus, Stomatococcus, Lactobacillus, Neisseria, Capnocytophaga, Haemophilus, Selenomonas and Centipeda species. The microflora in pericoronitis appeared similar to that of diseased periodontal pockets.

  10. COMPLICATIONS AFTER EXTRACTION OF IMPACTED THIRD MOLARS - LITERATURE REVIEW

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    Elitsa G. Deliverska

    2016-07-01

    Full Text Available Third molar surgery is the most common procedure performed by oral and maxillofacial surgeons worldwide. This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Complications, such as pain, dry socket, swelling, paresthesia of the lingual or inferior alveolar nerve, bleeding, and infection are most common. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical history, oral contraceptives, presence of pericoronitis, poor oral hygiene, smoking, type of impaction, relationship of third molar to the inferior alveolar nerve, surgical time, surgical technique, surgeon experience, use of perioperative antibiotics, use of topical antiseptics, use of intra-socket medications, and anaesthetic technique. For the general dental practitioner, as well as the oral and maxillofacial surgeon, it is important to be familiar with all the possible complications after this procedure. This improves patient education and leads to prevention, early recognition and management.

  11. Use of sevoflurane inhalation sedation for outpatient third molar surgery.

    Science.gov (United States)

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

    1999-01-01

    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.

  12. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans

    Science.gov (United States)

    Shen, Bing; Dong, Lin; Xiao, Shuhai; Lang, Xianguo; Huang, Kangjun; Peng, Yongbo; Zhou, Chuanming; Ke, Shan; Liu, Pengju

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (~2,500-750 million years ago, Ma) subtidal successions, but extremely rare in rocks isotopes, we show that molar tooth structures may have formed within sediments where microbial sulphate reduction and methanogenesis converged. The convergence was driven by the abundant production of methyl sulphides (dimethyl sulphide and methanethiol) in euxinic or H2S-rich seawaters that were widespread in Proterozoic continental margins. In this convergence zone, methyl sulphides served as a non-competitive substrate supporting methane generation and methanethiol inhibited anaerobic oxidation of methane, resulting in the buildup of CH4, formation of degassing cracks in sediments and an increase in the benthic methane flux from sediments. Precipitation of crack-filling microspar was driven by methanogenesis-related alkalinity accumulation. Deep ocean ventilation and oxygenation around 750 Ma brought molar tooth structures to an end.

  13. Variation in buccal surface morphology of deciduous first molars

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    M Simratvir

    2012-01-01

    Full Text Available Background: The buccal bulge of the deciduous first molars has always been a restorative challenge to the pediatric dentist. Morphologically it may vary from a slight prominence to a well-developed cusp-like structure. Aim: This study was conducted to determine the variable buccal surface morphology of deciduous first molar and its clinical relevance. Materials and Methods: A prospective study was conducted whereby 2016 patients visiting the outpatient clinic of dental hospital over 1 year were evaluated. Any variation in buccal surface morphology of the deciduous first molars was recorded photographically or by replicating in dental stone. Results: Varied morphological patterns on buccal surface were observed for which a new classification scheme has been proposed. Conclusion: The surface morphology of deciduous teeth crowns must be studied carefully as it may be indicative of pulpal extensions and accessory roots, requiring consideration during restorative treatment planning.

  14. Solution viscosity – molar mass relationships for poly(butylene succinate and discussion on molar mass analysis

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    Q. Charlier

    2015-05-01

    Full Text Available Poly(butylene succinate (PBS is currently developing due to its biodegradability and the similarity of its mechanical properties to those of polyolefins. Relationships between the number average molar mass, Mn, and solution viscosity such as [η] and ηred were derived for this aliphatic polyester. Mn values were determined by end-group analysis and size exclusion chromatography (SEC. Mark-Houwink-Sakurada (MHS parameters were proposed in two solvents and for the different molar masses and viscosity measurement methods. As an example, the MHS equations were respectively, [η] =6.4•10–4•Mn0.67 in chloroform and [η] = 7.1•10–4•Mn0.69 in 50/50 wt% 1,2-dichlorobenzene/phenol at 25°C for molar masses measured by SEC in hexafluoro isopropanol (HFIP with poly(methyl methacrylate (PMMA standards. Empirical relationships were also suggested to derive Mn directly from reduced viscosity, ηred, which is much easier to determine than intrinsic viscosity. With these data, the number average molar mass of PBS can be conveniently estimated from a single viscosity measurement. In addition, it was shown that PBS contains 1–2 wt% of cyclic oligomers produced during esterification and that molar masses determined by taking this fraction into account or not were significantly different, especially for long chains.

  15. Sex assessment by molar odontometrics in North Indian population

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    Ramandeep Singh Narang

    2015-01-01

    Full Text Available Introduction: Human identification is based on scientific principles, mainly involving dental records, fingerprints, estimation of age, postmortem reports, differentiation by blood groups, and DNA comparisons. Sex assessment is one of the prime factors employed to assist with the identification of an individual. Aims and Objective: To investigate univariate sex differences in the dimensions of permanent first molars and to assess sex, based on buccolingual (BL and mesiodistal (MD dimensions of permanent first molars in a population of north India. In addition, the study intended to evaluate the reliability of dimensional variation of these teeth in assessment of sex among the population. Materials and Methods: The study sample consists of 410 adult individuals (200 males and 210 females, from a north Indian population. The BL and MD diameters of the permanent first molars were measured using digital vernier callipers. Results: It was observed statistically significant difference between males and females with P < 0.05, in maxillary casts in both BL and MD dimensions; but only in the MD dimension in mandibular casts. A high level of sexual dimorphism of 7.7% was found in the BL dimension of the maxillary right first molar. The accuracy of sex assessment by each dimension was deliberated by univariate analyses with an overall accuracy ranging from 67.5 to 88% for various dimensions. Conclusion: Sexual dimorphism of teeth is population specific and among north Indian population, BL and MD dimensions in maxillary first molar and MD dimension in mandibular first molar can be used for sex assessment.

  16. Fibrous epulis associated with impacted lower right third molar

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    Ni Putu Mira Sumarta

    2009-12-01

    Full Text Available Background: Epulis or epulides are lesions associated with gingival tissues. Fibrous epulis is a type of hyperplastic fibrous tissue mass located at the gingival which is slow growing, painless, having same color as the oral mucosa and firm on palpation. Anterior regions of the oral cavity are the frequently affected sites as these areas are more prone to be affected by calculus deposition and poor plaque control due to frequent teeth malposition. Removal of any irritating factors and excision of the lesion are the usual treatments. Purpose: This case report presents a rare case of fibrous epulis which occurred in the posterior region of the oral cavity and associated with impacted lower third molar. Case: A case of fibrous epulis at the lower right third molar area of three months duration is presented. The mass was slow growing, painless and on examination it was a pedunculated mass overlying the unerupted lower right third molar, having same color with the oral mucosa and firm on palpation. Clinically, the lesion was diagnosed as fibrous epulis associated with impacted lower right third molar. Case management: The treatment were surgical excision of the epulis and removal of the lower right third molar. The histopathology result showed tissue with squamous epithelial lining, achanthotic fibrous connective tissue, mononuclear inflammatory cells and few capillaries without signs of malignancy. This is consistent with the diagnosis of fibrous epulis. Conclusion: Fibrous epulis, although frequently occurred at the anterior region of the oral cavity, may rarely grow at the area of lower third molar. This phenomenon supports the theory that epulis can grow on any surface of oral mucous membrane as long as local irritants are present.

  17. Quantitative determination of amorphous nicardipine hydrochloride in long acting formula (NIC-LA) using light anhydrous silicic acid.

    Science.gov (United States)

    Kohinata, Takeru; Fujii, Mitsuo; Nakamura, Souichiro; Hamada, Noritaka; Yonemochi, Etsuo; Terada, Katsuhide

    2004-12-01

    We investigated a method to quantitatively determine amorphous nicardipine hydrochloride (NIC) in the NIC-long acting formula (LA) model formulas prepared using NIC, light anhydrous silicic acid (LASA) and carboxymethylethylcellulose (CMEC). Consequently, since the quantity of total NIC in the formula can be determined by means of HPLC and crystal NIC can be determined by the differential scanning calorimetry (DSC) method because the heat of fusion (85.08 J/g) of NIC is constant and unaffected by excipients, we developed the HPLC-DSC method by which the quantity of amorphous NIC is calculated as the difference between the quantity of total NIC determined by HPLC and the quantity of crystal NIC determined by DSC. This practical HPLC-DSC method was confirmed to have good accuracy and reproducibility.

  18. Kinetic analysis for non-isothermal decomposition of un-irradiated and gamma-irradiated anhydrous cadmium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Culas, S.; Samuel, J. [Mar Ivanios College, Kerala (India). Dept. of Chemistry

    2014-04-01

    The thermal decomposition of untreated and γ-irradiated samples of anhydrous cadmium nitrate was performed under non-isothermal conditions at different heating rates (5, 10, 15 and 20 C min{sup -1}). The results showed that the decomposition proceeds in one major step with the formation of cadmium oxide as solid residue. The data were analysed by using both isoconversional and non-isoconversional methods. The activation energy was calculated by various model-free isoconversional methods: Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Friedman (FR) methods. Irradiation enhances the decomposition and the effect increases with the irradiation dose. The activation energy decreases on irradiation. The appropriate conversion model for the thermal decomposition process selected by means of the master-plot method agrees with phase boundary reaction with spherical symmetry (R3 mechanism) for both untreated and irradiated salts at all heating rates. (orig.)

  19. Thermal Decomposition of Anhydrous Alkali Metal Dodecaborates M2B12H12 (M = Li, Na, K

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    Liqing He

    2015-11-01

    Full Text Available Metal dodecaborates M2/nB12H12 are regarded as the dehydrogenation intermediates of metal borohydrides M(BH4n that are expected to be high density hydrogen storage materials. In this work, thermal decomposition processes of anhydrous alkali metal dodecaborates M2B12H12 (M = Li, Na, K synthesized by sintering of MBH4 (M = Li, Na, K and B10H14 have been systematically investigated in order to understand its role in the dehydrogenation of M(BH4n. Thermal decomposition of M2B12H12 indicates multistep pathways accompanying the formation of H-deficient monomers M2B12H12−x containing the icosahedral B12 skeletons and is followed by the formation of (M2B12Hzn polymers. The decomposition behaviors are different with the in situ formed M2B12H12 during the dehydrogenation of metal borohydrides.

  20. Sintesis ZSM-5 dari Fly Ash Sawit Sebagai Sumber Silika dengan Variasi Nisbah Molar Si/Al dan Temperatur Sintesis

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    Ida Zahrina

    2012-12-01

    Full Text Available Palm fly ash is biomass/waste in the  palm oil industry. Palm fly ash has high content of amorphous silica. ZSM-5 is one of synthetic zeolite which is widely used as catalyst in industries. ZSM-5 has high activity and selectivity to several hydrocarbon conversion reaction. Hence, ZSM-5 is being investigated for the conversion of vegetable oil to hydrocarbon.  It can be synthesized from silica and alumina. Sources of silica that can be added to the ZSM-5 synthesis,  are sodium silicate, hydrated silica, water glass sol silica, gelled silica, clay, precipitated silicaand calcined silica. ZSM-5 was synthesized free-template by using palm fly ash as silica source. In this research synthesis of ZSM-5 was carried out in autoclave at 18 hours and Na2O/Al2O3 molar ratio by various molar ratio from 30 to 40 and temperature in the range of 150 to 190 oC. The product was then analized using FTIR method. The best ZSM-5 product was obtained at Si/Al molar ratio of 40 and process temperature of 150 oC. Keywords: FTIR, Palm fly ash, ZSM-5

  1. Recent Advances in Anhydrous Solvents for CO2 Capture: Ionic Liquids, Switchable Solvents, and Nanoparticle Organic Hybrid Materials

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    YOUNGJUNE ePARK

    2015-10-01

    Full Text Available CO2 capture by amine scrubbing, which has a high CO2 capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO2 capture from flue gases. The findings from these demonstrations will significantly advance the field of CO2 capture in the coming years. While the latest efforts in aqueous amine solvents are exciting and promising, there are still several drawbacks to amine-based CO2 capture solvents including high volatility and corrosiveness of the amine solutions, as well as the high parasitic energy penalty during the solvent regeneration step. Thus, in a parallel effort, alternative CO2 capture solvents, which are often anhydrous, have been developed as the third-generation CO2 capture solvents. These novel classes of liquid materials include: Ionic Liquids (ILs, CO2-triggered switchable solvents (i.e., CO2 Binding Organic Liquids (CO2BOLs, Reversible Ionic Liquids (RevILs, and Nanoparticle Organic Hybrid Materials (NOHMs. This paper provides a review of these various anhydrous solvents and their potential for CO2 capture. Particular attention is given to the mechanisms of CO2 absorption in these solvents, their regeneration and their processability – especially taking into account their viscosity. While not intended to provide a complete coverage of the existing literature, this review aims at pointing the major findings reported for these new classes of CO2 capture media.

  2. Frequency of third molar agenesis: relation to jaw size

    OpenAIRE

    2014-01-01

    Introducción: este artículo forma parte de la investigación “Agenesia de terceros molares en los pacientes de las clínicas del Posgrado de Ortodoncia de la Universidad Antonio Nariño, 2011”, del grupo “Investigación en Salud Oral”. Algunos autores consideran que la agenesia de terceros molares puede ser una evidencia de tendencias evolutivas, en la que se observa una disminución en el tamaño de los maxilares y el número de dientes; sin embargo, en algunos estudios esto ha sido cuestionado. El...

  3. Treatment of Ectopic Mandibular Second Permanent Molar with Elastic Separators

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    R. Rajesh

    2014-01-01

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

  4. Evaluation of skeletal and dental age using third molar calcification, condylar height and length of the mandibular body

    Directory of Open Access Journals (Sweden)

    Sunil Gupta Kedarisetty

    2015-01-01

    Full Text Available Aim: To identify the most reliable method for age estimation among three variables, that is, condylar height, length of mandibular body and third molar calcification by Demirjian′s method. Materials and Methods: Orthopantomograms and lateral cephalograms of 60 patients with equal gender ratio were included in the study, among each gender 15 subjects were below 18 years and 15 subjects were above 18 years. Lateral cephalograms were traced, height of condyle and mandibular body are measured manually on the tracing paper, OPG′s were observed on radiographic illuminator and maturity score of third molar calcification was noted according to Demirjian′s method. All the measurements were subjected to statistical analysis. Results: The results obtained are of no significant difference between estimated age and actual age with all three parameters (P > 0.9780 condylar height, P > 0.9515 length of mandibular body, P > 0.8611 third molar calcification. Among these three, length of mandibular body shows least standard error test (i.e. 0.188. Conclusion: Although all three parameters can be used for age estimation, length of mandibular body is more reliable followed by height of condyle and third molar calcification.

  5. Pretreatment of corn stover by low moisture anhydrous ammonia (LMMA) in a pilot-scale reactor and bioconversion to fuel ethanol and industrial chemicals

    Science.gov (United States)

    Corn stover (CS) adjusted to 50%, 66% and 70% moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70% moisture CS was treated at 90 degree C and 100 degree C whereas the others were treated at 90 degree C only. The...

  6. Trace element partitioning between ilmenite, armalcolite and anhydrous silicate melt: Implications for the formation of lunar high-Ti mare basalts

    NARCIS (Netherlands)

    Kan Parker, M. van; Mason, P.R.D.; Westrenen, W. van

    2011-01-01

    We performed a series of experiments at high pressures and temperatures to determine the partitioning of a wide range of trace elements between ilmenite (Ilm), armalcolite (Arm) and anhydrous lunar silicate melt, to constrain geochemical models of the formation of titanium-rich melts in the Moon. Ex

  7. Control of powdery mildew on glasshouse-grown roses and tomatoes in the Netherlands using anhydrous milk fat and soybean oil emulsions

    NARCIS (Netherlands)

    Wurms, K.V.; Hofland-Zijlstra, Jantineke

    2015-01-01

    Powdery mildew (PM) is a very serious disease affecting glasshouse-grown roses and tomatoes in the Netherlands. Control is limited because of resistance to existing fungicides. Anhydrous milk fat (AMF) and soybean oil (SBO) emulsions were evaluated for control of PM in roses and tomatoes. Both AM

  8. Restauraciones cerámicas en molares jóvenes con endodoncia Ceramics restorations in young molars with endodontic

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    M. Urdaneta Quintero

    2009-12-01

    Full Text Available Objetivo: Efectuar restauraciones cerámicas Cerec (feldespática y de dióxido de circonio en molares jóvenes con endodoncia, para prevenir complicaciones en el aparato estomatognático por la pérdida de estos dientes. Material y métodos: Se describe la confección de restauraciones cerámicas a nivel de la zona molar mandibular derecha de un paciente del género femenino de 18 años de edad, a quien se le realizó radiografía periapical, por presentar dolor espontáneo en el lado derecho mandibular. Se diagnosticó una pulpitis irreversible en el primer y segundo molar que fue tratada endodónticamente. Las restauraciones cerámicas de ambos molares fueron confeccionadas con los sistemas CAD/CAM Cerec y evaluadas clínicamente a los 6 y 12 meses, de acuerdo a los criterios establecidos por el Servicio de Salud Pública de los Estados Unidos (USPHS. Resultados: La evaluación clínica evidenció que las estructuras de cerámica feldespática y de dióxido de circonio ofrecen en el lapso evaluado, adecuada forma anatómica, adaptación marginal, estabilidad en el color, ausencia de caries recidiva a nivel de dientes del sector posterior con tratamiento endodóntico y aceptación del paciente.Purpose: Make a ceramic restoration (feldsphatic and zirconium dioxide in young molars with endodontic treatment, to prevent further complications in the stomatognathic apparatus for the loss of these teeth. Material and methods: It describes the making of ceramic restorations in the right mandibular molar area to a female patient of 18 years old, to whom it was made a periapical radiography, for presenting spontaneous pain on the mandibular right side. It was diagnosed as an irreversible pulpitis at the first and second molar, that were treated endodontically. The ceramic restorations of both molars were made with the Cerec CAD/CAM system and were examined after 6 and 12 months in accordance with the US Public Health Service (USPHS criteria at baseline

  9. Cicatrización periodontal del segundo molar mandibular tras la exodoncia del tercer molar mandibular incluido

    OpenAIRE

    Inocêncio Teixeira de Faria, Ana Cristina

    2015-01-01

    La extracción quirúrgica del tercer molar (M3) puede provocar complicaciones periodontales en la cara distal del segundo molar (M2) adyacente. Se realizó un estudio clínico prospectivo a 12 meses en 25 pacientes jóvenes sanos (edad media 21 años) sometidos a 40 extracciones quirúrgicas de M3 mandibulares incluidos con elevado riesgo periodontal, con objeto de estudiar la cicatrización periodontal espontánea en la cara distal del M2. Prequirúrgicamente y a 3, 6 y 12 meses tras l...

  10. Anhydrate to hydrate solid-state transformations of carbamazepine and nitrofurantoin in biorelevant media studied in situ using time-resolved synchrotron X-ray diffraction.

    Science.gov (United States)

    Boetker, Johan P; Rantanen, Jukka; Arnfast, Lærke; Doreth, Maria; Raijada, Dhara; Loebmann, Korbinian; Madsen, Cecilie; Khan, Jamal; Rades, Thomas; Müllertz, Anette; Hawley, Adrian; Thomas, Diana; Boyd, Ben J

    2016-03-01

    Transformation of the solid-state form of a drug compound in the lumen of the gastrointestinal tract may alter the drug bioavailability and in extreme cases result in patient fatalities. The solution-mediated anhydrate-to-hydrate phase transformation was examined using an in vitro model with different biorelevant media, simulated fasted and fed state intestinal fluids containing bile salt and dioleoylphosphatidylcholine (DOPC) micelles, DOPC/sodium dodecyl sulfate (SDS) mixture, bile salt solution and water. Two anhydrate compounds (carbamazepine, CBZ and nitrofurantoin, NF) with different overall transformation time into hydrate form were used as model compounds. The transformations were monitored using direct structural information from time-resolved synchrotron X-ray diffraction. The kinetics of these transformations were estimated using multivariate data analysis (principal component analysis, PCA) and compared to those for nitrofurantoin (NF). The study showed that the solution-mediated phase transformation of CBZ anhydrate was remarkably faster in the DOPC/SDS medium compared to transformation in all the other aqueous dispersion media. The conversion time for CBZ anhydrate in water was shorter than for DOPC/SDS but still faster than the conversion seen in fed and fasted state micellar media. The conversion of CBZ anhydrate to hydrate was the slowest in the solution containing bile salt alone. In contrast, the solution-mediated phase transformations of NF did only show limited kinetic dependence on the dispersion media used, indicating the complexity of the nucleation process. Furthermore, when the CBZ and NF material was compacted into tablets the transformation times were remarkably slower. Results suggest that variations in the composition of the contents of the stomach/gut may affect the recrystallization kinetics, especially when investigating compounds with relatively fast overall transformation time, such as CBZ.

  11. Molar Intubation for Intra Oral Swellings:Our Experience

    Directory of Open Access Journals (Sweden)

    Meenoti Potdar

    2008-01-01

    Full Text Available Molar intubation is a technique of laryngoscopy that can be used for anticipated difficult intubation in cases where standard laryngoscopy technique is difficult due to presence of any intraoral mass that anatomically hampers laryngoscopy or that bleeds on touch. This technique is very easy, reliable and rewarding but should be practiced on normal patients for easy application in actual difficult cases.

  12. Coronectomy may be a way of managing impacted third molars

    NARCIS (Netherlands)

    Ghaeminia, H.

    2013-01-01

    Data sourcesTPubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) and the grey literature database SIGLE.Study selectionRandomised controlled trials (RCTs) and non-randomised controlled trials (CCTs) that compared coronectomy with total removal for third molar ext

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

    Directory of Open Access Journals (Sweden)

    Raquel Gonçalves Vieira-Andrade

    2012-08-01

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

  14. Lower molar and incisor displacement associated with mandibular remodeling.

    Science.gov (United States)

    Baumrind, S; Bravo, L A; Ben-Bassat, Y; Curry, S; Korn, E L

    1997-01-01

    The purpose of this study was to quantify the amount of alveolar modeling at the apices of the mandibular incisor and first molar specifically associated with appositional and resorptive changes on the lower border of the mandible during growth and treatment. Cephalometric data from superimpositions on anterior cranial base, mandibular implants of the Björk type, and anatomical "best fit" of mandibular border structures were integrated using a recently developed strategy, which is described. Data were available at annual intervals between 8.5 and 15.5 years for a previously described sample of approximately 30 children with implants. The average magnitudes of the changes at the root apices of the mandibular first molar and central incisor associated with modeling/remodeling of the mandibular border and symphysis were unexpectedly small. At the molar apex, mean values approximated zero in both anteroposterior and vertical directions. At the incisor apex, mean values approximated zero in the anteroposterior direction and averaged less than 0.15 mm/year in the vertical direction. Standard deviations were roughly equal for the molar and the incisor in both the anteroposterior and vertical directions. Dental displacement associated with surface modeling plays a smaller role in final tooth position in the mandible than in the maxilla. It may also be reasonably inferred that anatomical best-fit superimpositions made in the absence of implants give a more complete picture of hard tissue turnover in the mandible than they do in the maxilla.

  15. Unilateral maxillary molar distalization with zygoma-gear appliance.

    Science.gov (United States)

    Kilkis, Dogan; Bayram, Mehmet; Celikoglu, Mevlut; Nur, Metin

    2012-08-01

    The aim of this study was to present the orthodontic treatment of a 15-year-old boy with a unilateral maxillary molar distalization system, called the zygoma-gear appliance. It consisted of a zygomatic anchorage miniplate, an inner bow, and a Sentalloy closed coil spring (GAC International, Bohemia, NY). A distalizing force of 350 g was used during the distalization period. The unilateral Class II malocclusion was corrected in 5 months with the zygoma-gear appliance. The maxillary left first molar showed distalization of 4 mm with an inclination of 3°. The maxillary premolars moved distally with the help of the transseptal fibers. In addition, there were slight decreases in overjet (-0.5 mm) and maxillary incisor inclination (-1°), indicating no anchorage loss from the zygoma-gear appliance. Preadjusted fixed appliances (0.022 × 0.028-in, MBT system; 3M Unitek, Monrovia, Calif) were placed in both arches to achieve leveling and alignment. After 14 months of unilateral distalization with the zygoma-gear appliance and fixed appliances, Class I molar and canine relationships were established with satisfactory interdigitation of the posterior teeth. Acceptable overjet and overbite were also achieved. This article shows that this new system, the zygoma-gear appliance, can be used for unilateral maxillary molar distalization without anchorage loss.

  16. SECONDARY RETENTION OF PERMANENT MOLARS - A REPORT OF 5 FAMILIES

    NARCIS (Netherlands)

    RAGHOEBAR, GM; TENKATE, LP; HAZENBERG, CAM; BOERING, G; VISSINK, A

    1992-01-01

    The aetiopathogenesis of secondary retention is not fully understood, but heredity is involved in at least some cases. In this study first-degree relatives of 52 patients with secondary retention of permanent molars were screened for the presence of the same phenomenon in their dentition. Familial o

  17. Antibiotic prophylaxis in third molar surgery: a review

    NARCIS (Netherlands)

    Oomens, M.A.E.; Forouzanfar, T.

    2012-01-01

    Objective Controversy exists about the efficacy of antibiotic prophylaxis in preventing complications after lower third molar surgery. For evidence-based recommendation, a review was performed on clinical trials reporting the use of antibiotic prophylaxis compared with no treatment or placebo with "

  18. Non-compliance Appliances for Upper Molar Distalization: An Overview.

    Science.gov (United States)

    Noorollahian, Saeed; Alavi, Shiva; Shirban, Farinaz

    2015-01-01

    Tooth Size Arch-length Discrepancy (TSALD) is a common problem in orthodontics. Its clinical signs are tooth crowding, impaction and incisor proclination. The treatment options are dental arch expansion or tooth mass reduction (stripping or extraction). The "extraction versus non-extraction" controversy has been widely debated in the orthodontic literature. Distalization is a kind of arch expansion in anetro-posterior dimension. Several studies have evaluated both the therapeutic effectiveness and the side effects of the appliances for this method of space gaining. In some cases molar distalization is preferred, e.g., a patient with acceptable profile and skeletal pattern and half cusp Class II molar malocclusion or even less. In some cases molar distalization is the only way, e.g., the patient with previous upper premolar extraction and excessive overijet, or a skeletal Class III patient with previous upper premolar extraction needed upper anterior teeth retraction to create reverse overjet aspre surgical orthodontic decompensation. In this review article, we described non-compliance upper molar distalizing appliances.

  19. The chronology of third molar mineralization by digital orthopantomography.

    Science.gov (United States)

    Maled, Venkatesh; Vishwanath, S B

    2016-10-01

    The present study was designed to determine the chronology of third molar mineralization to establish Indian reference data and to observe the advantages of digital orthopantomography. Therefore, a cross-sectional study was undertaken by evaluating 167 digital orthopantomographs in order to assess the mineralization status of the mandibular third molar of Caucasian individuals (85 males and 82 females) between the age of 14 and 24. The evaluation was carried out using the 8-stage developmental scheme of Demirjian et al (1973). The range, mean age, standard deviation and Student t-test are presented for each stage of mineralization in all four quadrants. Statistically significant differences between males and females were not found for all four third molars. All the individuals in this study with mature third molar were at least 18 years of age. For medicolegal purposes, the likelihood of whether an Indian is older than 18 years or not was determined. The advantage of digital orthopantomography in the interpretation of the tooth mineralization over the traditional method was acknowledged.

  20. Factors associated with molar incisor hypomineralization in Thai children.

    Science.gov (United States)

    Pitiphat, Waranuch; Luangchaichaweng, Sarunporn; Pungchanchaikul, Patimaporn; Angwaravong, Onauma; Chansamak, Nusara

    2014-08-01

    Molar incisor hypomineralization (MIH) is a qualitative developmental enamel defect that affects one to four permanent first molars, with or without involvement of permanent incisors. Its etiology is of systemic origin, but is not well understood. Therefore, we conducted this cross-sectional study to examine pre-, peri-, and postnatal risk factors for MIH among children, 7-8 yr of age, in urban areas of Khon Kaen, Thailand. Molar incisor hypomineralization defects were diagnosed using the European Academy of Pediatric Dentistry criteria. Mothers or primary caregivers were interviewed on maternal medical history and habits during pregnancy, pregnancy and delivery complications, and the child's medical history. Molar incisor hypomineralization defects were observed in 78 (27.7%) of 282 children. Multiple logistic regression analysis showed a statistically significant association between the development of MIH and Cesarean section (adjusted OR = 2.0, 95% CI = 1.1-3.7), complications during vaginal delivery (adjusted OR = 4.5, 95% CI = 1.9-11.0), and severe/chronic illness when under 3 yr of age (adjusted OR = 2.9, 95% CI = 1.6-5.0). There was no association of preterm birth and low birth weight with MIH. The results suggest that Cesarean section, complications during vaginal delivery, and poor health during the first 3 yr of life are independent risk factors for MIH.

  1. Molar incisor hypomineralization: review and recommendations for clinical management.

    Science.gov (United States)

    William, Vanessa; Messer, Louise B; Burrow, Michael F

    2006-01-01

    Molar incisor hypomineralization (MIH) describes the clinical picture of hypomineralization of systemic origin affecting one or more first permanent molars (FPMs) that are associated frequently with affected incisors. Etiological associations with systemic conditions or environmental insults during the child's first 3 years have been implicated. The complex care involved in treating affected children must address their behavior and anxiety, aiming to provide a durable restoration under pain-free conditions. The challenges include adequate anaesthesia, suitable cavity design, and choice of restorative materials. Restorations in hypomineralized molars appear to fail frequently; there is little evidence-based literature to facilitate clinical decisions on cavity design and material choice. A 6-step approach to management is described: (1) risk identification; (2) early diagnosis; (3) remineralization and desensitization; (4) prevention of caries and posteruption breakdown; (5) restorations and extractions; and (6) maintenance. The high prevalence of MIH indicates the need for research to clarify etiological factors and improve the durability of restorations in affected teeth. The purpose of this paper was to describe the diagnosis, prevalence, putative etiological factors, and features of hypomineralized enamel in molar incisor hypomineralization and to present a sequential approach to management.

  2. Odontometric analysis of permanent maxillary first molar in gender determination

    Science.gov (United States)

    Shireen, Ayesha; Ara, Syeda Arshiya

    2016-01-01

    Aims: This study was conducted to assess the sex determination potential from mesiodistal (MD) and buccolingual (BL) dimensions of permanent maxillary first molar. Subjects and Methods: The study was conducted in the Department of Oral Medicine and Radiology, Al-Badar Rural Dental College and Hospital, Gulbarga, Karnataka, on 600 subjects (300 male and 300 female), aged 17–25 years. The subjects were selected based on the inclusion and exclusion criteria set forth for the study. After obtaining informed consent, the intraoral measurements of MD and BL dimensions on casts of the first maxillary molars were taken using digital vernier caliper with resolution of 0.01 mm. Statistical Analysis Used: The data obtained were subjected to statistical analysis using paired and unpaired t-test to compare MD and BL dimensions between males and females. P ≤0.05 was considered statistically significant. Results: The mean MD width of the first maxillary molar was 10.60 ± 0.6644 mm (right) and 10.60 ± 0.6644 mm (left) in males and 10.40 ± 0.6255 mm (right) and 10.40 ± 0.6255 mm (left) in females. The mean BL width of the first maxillary molar was 11.60 ± 1.2227 mm (right) and 11.60 ± 1.2227 mm (left) in males and 11.20 ± 0.8440 mm (right) and 11.20 ± 0.8440 mm (left) in females. The differences between males and females in MD and BL dimensions measured were statistically significant (P < 0.05). Right and left MD dimensions exhibited sexual dimorphism of 1.92% and right and left BL dimensions exhibited sexual dimorphism of 3.57%. Conclusions: The MD and BL dimensions of the maxillary first molars may be used as an aid in sex discrimination. PMID:28123268

  3. Odontometric analysis of permanent maxillary first molar in gender determination

    Directory of Open Access Journals (Sweden)

    Ayesha Shireen

    2016-01-01

    Full Text Available Aims: This study was conducted to assess the sex determination potential from mesiodistal (MD and buccolingual (BL dimensions of permanent maxillary first molar. Subjects and Methods: The study was conducted in the Department of Oral Medicine and Radiology, Al-Badar Rural Dental College and Hospital, Gulbarga, Karnataka, on 600 subjects (300 male and 300 female, aged 17–25 years. The subjects were selected based on the inclusion and exclusion criteria set forth for the study. After obtaining informed consent, the intraoral measurements of MD and BL dimensions on casts of the first maxillary molars were taken using digital vernier caliper with resolution of 0.01 mm. Statistical Analysis Used: The data obtained were subjected to statistical analysis using paired and unpaired t-test to compare MD and BL dimensions between males and females. P ≤0.05 was considered statistically significant. Results: The mean MD width of the first maxillary molar was 10.60 ± 0.6644 mm (right and 10.60 ± 0.6644 mm (left in males and 10.40 ± 0.6255 mm (right and 10.40 ± 0.6255 mm (left in females. The mean BL width of the first maxillary molar was 11.60 ± 1.2227 mm (right and 11.60 ± 1.2227 mm (left in males and 11.20 ± 0.8440 mm (right and 11.20 ± 0.8440 mm (left in females. The differences between males and females in MD and BL dimensions measured were statistically significant (P < 0.05. Right and left MD dimensions exhibited sexual dimorphism of 1.92% and right and left BL dimensions exhibited sexual dimorphism of 3.57%. Conclusions: The MD and BL dimensions of the maxillary first molars may be used as an aid in sex discrimination.

  4. Distribution and characteristics of molar-incisor hypomineralization

    Directory of Open Access Journals (Sweden)

    Janković Svjetlana

    2014-01-01

    Full Text Available Background/Aim. Developmental disorders of teeth are the problems that are becoming more present in pediatric dentistry, especially on first permanent molars and incisors. Molar Incisor Hypomineralization (MIH is proposed term for this phenomenon. The aim of this study was to establish the MIH prevalence in children living in the Foča municipality (Bosnia and Herzegovina as well as to assess characteristics and expression of hypomineralization within the tested population. Methods. A total of 141 children from the Foča municipality, 8 years of age, were included in this study. Criteria according to Weerhejm have been used for diagnosis of hypomineralization: demarcated opacity (DO, post-eruptive breakdown (PEB, atypical restoration (AR, extracted molars due to MIH (E-MIH and unerupted tooth (UT. Level and the prominence of color changes have been determined for patients with DO, PEB and AR. Results. MIH in this area was present in 12.8% of children. The prevalence of MIH changes expressed in percentages was as follows: DO was at 9.2%, PEB in 3.5%, AR in 5.6%, while E-MIH was 5.6%. A total of 9.9% of the examinees had mild, 5.6% moderate, and 7.8% severe form of MIH. White form of MIH defects was found in 9.9% of the examinees, white-yellow one in 5.6% and yellow-brown color in 3.5% of the examined children. These changes were more often present in the lower jaw (60.3%. In total, 6.4% of children had these changes present only on molars, while 6.4% of them both on molars and incisors simultaneously. Conclusion. A total of 12.8% of the examinees with MIH is not to be disregarded. With timely diagnosis, prevention and therapy complications could be avoided or mitigated.

  5. Acute inflammation in horizontal incompletely impacted third molar with radiolucency in the elderly

    Directory of Open Access Journals (Sweden)

    Minoru Yamaoka

    2009-07-01

    Full Text Available Minoru Yamaoka, Yusuke Ono, Masahiro Takahashi, Masahide Ishizuka, Takayuki Uchihashi, Kouichi Yasuda, Takashi Uematsu, Kiyofumi FurusawaMatsumoto Dental University, Oral and Maxillofacial Surgery, Shiojiri, Nagano, JapanAbstract: Although radiolucency has been shown as a risk of infection, the poorly understood effects of aging on radiolucency correlate with acute pericoronitis, which has a high risk of infection extending any complications. We reviewed the records of 346 consecutive patients aged more than 41 years to evaluate whether pericoronal radiolucency below the crown in mandibular horizontal incompletely impacted third molars is related to acute inflammation. The frequency of acute inflammation in teeth with pericoronal radiolucency below the crown was similar to that in teeth without; however, the odds ratio of acute inflammation exhibited in women aged more than 61 years compared to women aged 41–50 years was 9.77 (95% confidence interval [CI]: 1.67–57.29; P <<0.05, and in women aged more than 61 years compared to women aged 51–60 years was 26.25 (95% CI: 2.94–234.38; P < 0.01. The odds ratio of severe acute inflammation exhibited in men aged more than 61 years compared to men aged 41–50 years was 16.67 (95% CI: 1.76–158.27; P < 0.01. These odds ratios indicate an association of acute pericoronitis, including the severe forms of acute inflammation that result from pericoronitis, with pericoronal radiolucency below the crown in the elderly.Keywords: radiolucency, mandible, third molar, acute inflammation, aging

  6. Anhydrous ringwoodites in the mantle transition zone: Their bulk modulus, solid solution behavior, compositional variation, and sound velocity feature

    Directory of Open Access Journals (Sweden)

    Xi Liu

    2016-06-01

    Full Text Available The isothermal bulk moduli of anhydrous Mg2SiO4-ringwoodite (Rw and Fe2SiO4-Rw, and other 4–2 oxide spinels at ambient P-T condition have been evaluated, and empirically fitted to a model as KT0 = 270.8(300 + 0.343(59*V0 + 23.04(269*EN-total, where KT0 is the isothermal bulk modulus in GPa, V0 the unit-cell volume in Å3 and EN-total the electronegativity total of all cations in the chemical formula. This model well reproduces all data used in its calibration, and may be used to predict the KT0 of other 4–2 oxide spinels. Combined with the generally linear volume–composition relationship of the Rw solid solutions along the join Mg2SiO4–Fe2SiO4, this model leads to a much smaller composition effect on the KT0: KT0 = 185.0(1 + 7.0(1*XFe, where XFe is the atomic ratio Fe/(Fe + Mg. Furthermore, a bulk composition-independent compositional variation with P has been disclosed for the Rw at the P-T conditions of the lower part of the mantle transition zone (MTZ: XFe = 0.222(41 – 0.0053(19*P, with P in GPa. The nearly ideal mixing behavior, much smaller composition effect on the bulk modulus, and significant compositional variation of the Rw in the lower part of the MTZ substantially increase the gradients of the Vs-P and Vp-P profiles to generally match those constrained by the seismic reference models PREM and AK135. If there is any global low-T anomaly at the depth of 660 km, its required magnitude is most likely not larger than 200 K.

  7. Effect of the route of administration of methylprednisolone on oedema and trismus in impacted lower third molar surgery.

    Science.gov (United States)

    Koçer, G; Yuce, E; Tuzuner Oncul, A; Dereci, O; Koskan, O

    2014-05-01

    Due to their anatomical position, the surgical removal of impacted third molars results in oedema, pain, and trismus. The purpose of this study was to evaluate the efficacy of supraperiosteal injection of methylprednisolone compared with an oral tablet form and intravenous (i.v.) injection in the prevention of postoperative pain and oedema associated with inflammation. This randomized, prospective, and controlled study included 44 patients. The patients were randomly divided into four groups: group 1 (control; no steroids), group 2 (local injection), group 3 (oral tablets), and group 4 (i.v. injection). On days 2 and 7 following surgery, linear oedema was determined using facial landmarks, and maximal mouth opening was measured. Postoperative mouth opening and swelling were evaluated for each route of methylprednisolone administration and compared. The female (59%) to male (41%) ratio was 1.44; the mean age of the patients was 29.6 years. The level of significance was set at Plower third molar surgery.

  8. [The relation of pericoronitis to the position of the mandibular third molar].

    Science.gov (United States)

    Lee, D K; Kim, B J

    1989-02-01

    Pericoronitis is the most commonly encountered pathologic condition involving the mandibular third molar. Because of the dangers associated with mandibular third molar pericoronitis, prophylactic extraction of third molar at high risk has been recommended. We studied 411 patients with mandibular third molar pericoronitis by clinical symptoms and radiographic measurement of mandibular third molar height, wideth and angulation. The results were as follows: 1. Mandibular third molar pericoronitis is frequently seen in third decade and there are no sexual difference significantely. 2. In inflammatory type of mandibular third molar pericoronitis, chronic pericoronitis occured more frequently than acute type. 3. In relation to angulation and height, mandibular third molar most likely to be afflicted with pericoronitis is vertical eruption at occlusal plane of the second molar. 4. In relation to angulation and width, it appears that the position of the mandibular third molar most likely to be afflicted with pericoronitis is in a vertically erupted tooth of which the space between the ramus and the distal side of the second molar is less than the mesiodistal diameter of crown. (Class II). 5. In relation to height and width, it appears that the position of the mandibular third molar most likely to be afflicted with pericoronitis is class II width (described above)at occlusal plane of the second molar.

  9. Space loss following premature loss of primary second molars.

    Science.gov (United States)

    Alnahwi, Hassan H; Donly, Kevin J; Contreras, Claudia I

    2015-01-01

    This study was designed to evaluate the amount of space loss (SL) caused by premature loss of primary second molars, determine whether the eruption status of permanent first molars is an important factor in the amount of SL, and evaluate the effectiveness of space maintainers (SMs) in SL prevention. SL associated with 100 prematurely extracted primary second molars was evaluated in 87 healthy patients. Teeth were divided into groups based on the use of SMs (36 with SM and 64 without SM). Bitewing and periapical radiographs taken before extraction and 6, 12, 24, 36, and 48 months after extraction were used to determine the amount of SL. Not every patient attended every recall appointment, so the sample size varied at different evaluation times. The most significant amount of SL occurred in the first 12 months after extraction. In patients who did not use an SM, at 6 months there was a mean SL of 2.12 mm (SD, 1.65 mm) and at 12 months there was a mean of 4.02 mm (SD, 1.65), with significantly more SL in the first 6 months (P 0.05). When patients without an SM were grouped by the eruption status of the permanent first molar, there was significantly more SL in the groups with unerupted first molars than there was in the groups with erupted first molars at both 6 months (P < 0.001) and 12 months (P < 0.05). At both 6 and 12 months, the amount of SL in patients who had an SM (n = 13 and n = 14, respectively) was not significantly different from the amount of SL in those who did not have an SM (n = 33 and n = 23, respectively). SMs should be placed as soon as possible following tooth extraction to prevent undue SL. Placement of an SM a year or more after extraction has minimal benefit, since most SL takes place within the first year. SL does occur even when SMs are used.

  10. The maximum water storage capacities in nominally anhydrous minerals in the mantle transition zone and lower mantle

    Science.gov (United States)

    Inoue, T.; Yurimoto, H.

    2012-12-01

    Water is the most important volatile component in the Earth, and affects the physicochemical properties of mantle minerals, e.g. density, elastic property, electrical conductivity, thermal conductivity, rheological property, melting temperature, melt composition, element partitioning, etc. So many high pressure experiments have been conducted so far to determine the effect of water on mantle minerals. To clarify the maximum water storage capacity in nominally anhydrous mantle minerals in the mantle transition zone and lower mantle is an important issue to discuss the possibility of the existence of water reservoir in the Earth mantle. So we have been clarifying the maximum water storage capacity in mantle minerals using MA-8 type (KAWAI-type) high pressure apparatus and SIMS (secondary ion mass spectroscopy). Upper mantle mineral, olivine can contain ~0.9 wt% H2O in the condition just above 410 km discontinuity in maximum (e.g. Chen et al., 2002; Smyth et al., 2006). On the other hand, mantle transition zone mineral, wadsleyite and ringwoodite can contain significant amount (about 2-3 wt.%) of H2O (e.g. Inoue et al., 1995, 1998, 2010; Kawamoto et al., 1996; Ohtani et al., 2000). But the lower mantle mineral, perovskite can not contain significant amount of H2O, less than ~0.1 wt% (e.g. Murakami et al., 2002; Inoue et al., 2010). In addition, garnet and stishovite also can not contain significant amount of H2O (e.g. Katayama et al., 2003; Mookherjee and Karato, 2010; Litasov et al., 2007). On the other hand, the water storage capacities of mantle minerals are supposed to be significantly coupled with Al by a substitution with Mg2+, Si4+ or Mg2+ + Si4+, because Al3+ is the trivalent cation, and H+ is the monovalent cation. To clarify the degree of the substitution, the water contents and the chemical compositions of Al-bearing minerals in the mantle transition zone and the lower mantle were also determined in the Al-bearing systems with H2O. We will introduce the

  11. Hydrogen bonding interactions between ethylene glycol and water: density, excess molar volume, and spectral study

    Institute of Scientific and Technical Information of China (English)

    ZHANG JianBin; ZHANG PengYan; MA Kai; HAN Fang; CHEN GuoHua; WEI XiongHui

    2008-01-01

    Studies of the density and the excess molar volume of ethylene glycol (EG)-water mixtures were carried out to illustrate the hydrogen bonding interactions of EG with water at different temperatures, The re-sults suggest that a likely complex of 3 ethylene glycol molecules bonding with 4 water molecules in an ethylene glycol-water mixture (EGW) is formed at the maximal excess molar volume, which displays stronger absorption capabilities for SO2 when the concentration of SO2 reaches 400×106 (volume ratio) in the gas phase. Meanwhile, FTIR and UV spectra of EGWs were recorded at various EG concentra-tions to display the hydrogen bonding interactions of EG with water. The FTIR spectra show that the stretching vibrational band of hydroxyl in the EGWs shifts to a lower frequency and the bending vibra-tional band of water shifts to a higher frequency with increasing the EG concentration, respectively. Furthermore, the UV spectra show that the electron transferring band of the hydroxyl oxygen in EG shows red shift with increasing the EG concentration. The frequency shifts in FTIR spectra and the shifts of absorption bands in UV absorption spectra of EGWs are interpreted as the strong hydrogen bonding interactions of the hydrogen atoms in water with the hydroxyl oxygen atoms of EG.

  12. Alveolar Osteitis: Patients′ compliance to post-extraction instructions following extraction of molar teeth

    Directory of Open Access Journals (Sweden)

    Osagie Akpata

    2013-01-01

    Full Text Available Background: To evaluate the effect of various combination of post-extraction regimen administered to patients who had intra-alveolar molar tooth extraction. Patients and Methods: One year prospective study involving 76 consenting patients who came for 1-week post-extraction review. The patients were placed on warm saline mouth rinse with (verbal instruction or without antibiotic and or analgesic therapy (written prescription, after intra-alveolar molar tooth extraction. Information was obtained from the patients through questionnaire and clinical examination. Results: The patients were placed on warm saline mouth rinse (n = 29, 38.2% only, warm saline rinse, antibiotics (Amoxicillin and metronidazole and Paracetamol (n = 31, 40.8%, Paracetamol and warm saline rinse (n = 12, 15.8% and antibiotics (Amoxicillin and metronidazole and Paracetamol (n = 4, 5.3%. A total of 63 (82.9% patients complied with the post-extraction regimen, giving a significant high compliance to the post-extraction instructions (P = 0.001. There were 10 (13.2% cases of post-extraction localised alveolar osteitis, with predilection for the lower molar teeth (n = 6, 7.9% and a significant predilection for females (n = 8, 10.5% [P = 0.005]. Overall, there were five (6.6% cases each of localised alveolar osteitis in the compliant patients (n = 63, 82.9% and non-compliant patients (n = 13, 17.1%, giving a ratio of 1:13 and 1:3, respectively. There was significant association of compliance with post-extraction instruction and the reduced incidence of localized alveolar osteitis (P = 0.015. Conclusion: This study showed a significant patients′ compliance with post-extraction warm saline rinse, prophylactic antibiotics and analgesic and a corresponding significant reduction in the incidence of localised alveolar osteitis following intra-alveolar molar tooth extraction. This study emphasises the need to properly educate patients on the effect of compliance to various combination of

  13. Molar Uprighting Using Mini-Screws after Distalization by the Pendulum Appliance: A Case Report

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    Amir Moradi

    2013-12-01

    Full Text Available A 16-year-old Class II female patient was treated without tooth extraction. The upper first molars were distalized by the Pendulum appliance. After six months, the molars tipped significantly to the distal. To correct this side effect, we decided to upright the molars using skeletal anchorage. On each side, a mini-screw was inserted between first and second premolars in the buccal cortical plate. An auxiliary spring was placed between the mini-screw head and the molar buccal tube. The resultant moment made the first molar upright. In addition, the side effects of this mechanic, i.e. molar intrusion and molar buccal tipping, counteract the extrusion and medial movement caused by the Pendulum Appliance. The aim of this case report was to present an innovative method for molar uprighting using skeletal anchorage.

  14. The third molar as an age marker in adolescents: new approach to age evaluation.

    Science.gov (United States)

    Rozkovcova, Eva; Dostalova, Tatjana; Markova, Marie; Broukal, Zdenek

    2012-09-01

    Adolescence is a relatively short period between childhood and adulthood. It is very difficult to determine adulthood based on biological indicators. The third molar may be considered a potential age marker for the period between the ages of 16-21. Our study evaluated a set of 1700 panoramic radiographs of individuals aged between 5 and 21 years. Results confirmed the statistically significant difference in the course of third molars development. The mean deviation for individuals with one third molar agenesis is -0.98 years, for individuals with two third molars agenesis -1.89 years, and with three molars agenesis -3.28 years. Thus, the extent of the deviation is directly proportional to the number of unformed third molars. The calculation of age according to the mean of stages of all third molars could lead to the underestimation of age. No intergender differences were found. Age determination using third molars could be used for forensic purposes.

  15. Spontaneous emergence of overgrown molar teeth in a colony of Prairie voles (Microtus ochrogaster)

    Institute of Scientific and Technical Information of China (English)

    Andrew H Jheon; Michaela Prochazkova; Michael Sherman; Devanand S Manoli; Nirao M Shah; Lawrence Carbone; Ophir Klein

    2015-01-01

    Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles (Microtus ochrogaster). We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography (microCT) analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth.

  16. Periodontal pathogens in erupting third molars of periodontally healthy subjects.

    Science.gov (United States)

    Rajasuo, A; Sihvonen, O J; Peltola, M; Meurman, J H

    2007-09-01

    The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Tannerella forsythensis in bacteriologic samples of 5-7-mm deep mandibular third-molar pericoronal pockets was analysed by polymerase chain reaction, to test the hypothesis that these sites would harbour the bacteria. The patients were periodontally healthy 20-year-old Finnish male conscripts. Sixteen had acute pericoronitis, 28 chronic pericoronitis, and 15 were symptom-free controls. A. actinomycetemcomitans was detected in only 7% of the samples from chronic pericoronitis cases, whereas P. gingivalis was positive in 20% of the symptom-free versus 69% (P = 0.018) of the acute and 57% (P = 0.044) of the chronic cases. The percentages for P. intermedia were 93, 94 and 93%, and for T. forsythensis 47, 63 and 57%, respectively. These results confirm that, apart from A. actinomycetemcomitans, periodontopathogens are common in third-molar sites in periodontally healthy individuals.

  17. Fraktur Patologis Mandibula Akibat Komplikasi Odontektomi Gigi Molar 3 Bawah

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    Dicky Firmansyah

    2012-10-01

    Full Text Available The removal of impacted mandibular molar by surgery (odontectomi is a common procedure done by the dentist in daily practice. A well and proper operation technique is required to avoid unexpected complication after odontectomy. A 48 years oldwomen is reported with pathological sinistra mandible angle fracture after odontectomy of mandibular third molar done by Yordania Oral Surgeon two month ago. Patient was refered to Departemen of Oral Surgery RSCM. Reposition and fragmen fixation using plate-srew and arch bar. In this paper, writer try to discuss about the posible cause of complication. Hopefully, dentists will be more careful in doing odontectomy procedure, to avoid unexpected complications.DOI:10.14693/jdi.v15i3.25

  18. 无水苯甲酸锂的合成、结构表征及热化学研究%Synthesis, Structure Characterization and Thermochemistry of Anhydrous Lithium Benzoinate

    Institute of Scientific and Technical Information of China (English)

    何东华; 邸友莹; 杨伟伟; 孔玉霞; 淡文彦; 谭志诚

    2009-01-01

    用分析纯苯甲酸和一水氢氧化锂作为反应物, 采用水热合成法制得苯甲酸锂. 利用X射线粉末衍射、 FTIR、 元素分析及化学分析等方法对样品进行组成和结构表征. 采用精密自动绝热热量计测量了其在80~400 K范围内的摩尔热容, 利用最小二乘法将此温区热容实验值对折合温度进行拟合, 得到热容随温度变化的多项式方程. 通过设计合理的热化学循环, 选用0.1 mol/L HCl溶液作为量热溶剂, 利用等温环境溶解-反应热量计分别测定合成反应的反应物和产物在所选溶剂中的溶解焓, 得到反应焓Δ_rH~φ -_m=-(9.75±0.27) kJ/mol. 利用Hess定律计算出苯甲酸锂的标准摩尔生成焓Δ_fH~φ-_m(C6H5COOLi, s)=-(307.82±0.57) kJ/mol.%Benzoic acid and lithium hydroxide with the analytical grade were chosen as the reactants, and the lithium benzoinate was synthesized by means of hydrothermal synthesis. XRD,FTIR and elementary and chemical analyses were applied to characterize its composition and structure. Low-temperature heat capacities of the compound were measured via a precision automated adiabatic calorimeter over the temperature range from 80-400 K. A polynomial equation of the heat capacities as a function of the temperature was fitted by the least square method. A reasonable thermochemical cycle was designed on the basis of the preparation reaction of the substance, 0.1 mol/L of HC1 solution was chosen as the calorimetric solvent, and the standard molar enthalpies of dissolution for the reactants and products of the hydrothermal reaction in the selected solvents were measured by an isoperibol solution-reaction calorimeter, respectively. The enthalpy change of the preparation reaction was determined as △_rH_m~θ =-(9.75±0.27) kJ/mol from the standard molar enthalpies of dissolution. Eventually, the standard molar enthalpy of formation of anhydrous lithium benzoinate was derived to be △_rH_m~θ =-(307.82±0.57) kJ/mol by

  19. Fate of the molar dental lamina in the monophyodont mouse.

    Science.gov (United States)

    Dosedělová, Hana; Dumková, Jana; Lesot, Hervé; Glocová, Kristýna; Kunová, Michaela; Tucker, Abigail S; Veselá, Iva; Krejčí, Pavel; Tichý, František; Hampl, Aleš; Buchtová, Marcela

    2015-01-01

    The successional dental lamina (SDL) plays an essential role in the development of replacement teeth in diphyodont and polyphyodont animals. A morphologically similar structure, the rudimental successional dental lamina (RSDL), has been described in monophyodont (only one tooth generation) lizards on the lingual side of the developing functional tooth. This rudimentary lamina regresses, which has been proposed to play a role in preventing the formation of future generations of teeth. A similar rudimentary lingual structure has been reported associated with the first molar in the monophyodont mouse, and we show that this structure is common to all murine molars. Intriguingly, a lingual lamina is also observed on the non-replacing molars of other diphyodont mammals (pig and hedgehog), initially appearing very similar to the successional dental lamina on the replacing teeth. We have analyzed the morphological as well as ultrastructural changes that occur during the development and loss of this molar lamina in the mouse, from its initiation at late embryonic stages to its disappearance at postnatal stages. We show that loss appears to be driven by a reduction in cell proliferation, down-regulation of the progenitor marker Sox2, with only a small number of cells undergoing programmed cell death. The lingual lamina was associated with the dental stalk, a short epithelial connection between the tooth germ and the oral epithelium. The dental stalk remained in contact with the oral epithelium throughout tooth development up to eruption when connective tissue and numerous capillaries progressively invaded the dental stalk. The buccal side of the dental stalk underwent keratinisation and became part of the gingival epithelium, while most of the lingual cells underwent programmed cell death and the tissue directly above the erupting tooth was shed into the oral cavity.

  20. Fate of the molar dental lamina in the monophyodont mouse.

    Directory of Open Access Journals (Sweden)

    Hana Dosedělová

    Full Text Available The successional dental lamina (SDL plays an essential role in the development of replacement teeth in diphyodont and polyphyodont animals. A morphologically similar structure, the rudimental successional dental lamina (RSDL, has been described in monophyodont (only one tooth generation lizards on the lingual side of the developing functional tooth. This rudimentary lamina regresses, which has been proposed to play a role in preventing the formation of future generations of teeth. A similar rudimentary lingual structure has been reported associated with the first molar in the monophyodont mouse, and we show that this structure is common to all murine molars. Intriguingly, a lingual lamina is also observed on the non-replacing molars of other diphyodont mammals (pig and hedgehog, initially appearing very similar to the successional dental lamina on the replacing teeth. We have analyzed the morphological as well as ultrastructural changes that occur during the development and loss of this molar lamina in the mouse, from its initiation at late embryonic stages to its disappearance at postnatal stages. We show that loss appears to be driven by a reduction in cell proliferation, down-regulation of the progenitor marker Sox2, with only a small number of cells undergoing programmed cell death. The lingual lamina was associated with the dental stalk, a short epithelial connection between the tooth germ and the oral epithelium. The dental stalk remained in contact with the oral epithelium throughout tooth development up to eruption when connective tissue and numerous capillaries progressively invaded the dental stalk. The buccal side of the dental stalk underwent keratinisation and became part of the gingival epithelium, while most of the lingual cells underwent programmed cell death and the tissue directly above the erupting tooth was shed into the oral cavity.

  1. Flow properties of ice cream mix prepared from palm oil: anhydrous milk fat blends.

    Science.gov (United States)

    Rosnani, A I Wan; Aini, I Nor; Yazid, A M M; Dzulkifly, M H

    2007-05-15

    Ice cream mixes containing 33.4% total solids including 10% fat, 11.1% milk solid-non fat (MSNF), 12% sugar, 0.35% commercial blend of emulsifier/ stabiliser and water were produced. The blending of PO with AMF were conducted at three different ratios 30: 70, 50: 50 and 70: 30, respectively. The experimental ice cream mixes were compared with a control ice cream mix prepared from AMF. The flow properties were measured after ageing at 0, 1, 1.5, 2 and 24 h and determined using a controlled stress rheometer (Haake RS 100). The Power Law and Casson equation was employed to estimate the yield stress of an ice cream mixes. The regression coefficients (r) was represented well by the Casson model (r > 0.99) for all the samples, indicating goodness of fit. The profiles of the consistency coefficients (K(c)) were quite similar for all experimental samples, which could be attributed to the fact that all the samples exhibited similar viscoelastic behaviour. The flow behaviour index (n) of an ice cream mix prepared from PO and their blends with AMF were less then 1.0 (range 0.04-0.08) indicating that they were psuedoplastic fluid. The eta(o) at shear rate 20(-1) indicated higher degree of viscosity in AMF.

  2. Prevention and treatment of neurosensory disturbance after lower third molar surgery

    OpenAIRE

    Leung, Yiu-yan; 梁耀殷

    2014-01-01

    Neurosensory deficit is a well-reported complication after lower third molar surgery. It is useful to know the outcomes of the available treatments for neurosensory deficit after third molar surgery. It is more important to prevent nerve injury from third molar surgery. This thesis aims1) to evaluate the outcomes of treatments for neurosensory deficit after lower third molar surgery; 2) to investigate the effect of permanent neurosensory deficit from the patient’s perspective;3) to identify r...

  3. Characterization on the Mean Molar Absorptivity of Amino Acids in Microbial Lipopeptides

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid composition exactly equivalent to that of the peptide chain of the corresponding lipopeptide were determined based on calculation or experimental. The significance of the results is that the mean molar absorption coefficients strongly demonstrate the regular patterns, though different amino acids bear quite different molar absorption coefficients.

  4. Molar macrowear reveals Neanderthal eco-geographic dietary variation.

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    Luca Fiorenza

    Full Text Available 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.

  5. A Neanderthal lower molar from Stajnia Cave, Poland.

    Science.gov (United States)

    Dąbrowski, P; Nowaczewska, W; Stringer, C B; Compton, T; Kruszyński, R; Nadachowski, A; Stefaniak, K; Urbanowski, M

    2013-04-01

    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.

  6. Decontamination of tried-in orthodontic molar bands.

    Science.gov (United States)

    Fulford, M R; Ireland, A J; Main, B G

    2003-12-01

    Molar bands are commonly used to retain orthodontic attachments on posterior teeth and due to the variation in the size of such teeth, it is usually necessary to 'try in' several bands before the correct one is selected. A possible concern with re-using such bands is the lack of cross-infection control, even following autoclaving, due to the presence of one or more small bore lumen (the archwire and headgear tubes). The aim of this experiment was, therefore, to determine whether such bands could be successfully decontaminated so that they could be re-used without a cross-infection risk. Two hundred orthodontic molar bands that had previously been tried in patients' mouths, but not cemented into place, were tested. Each band was decontaminated using an enzymatic cleaner/disinfectant and then sterilized using either a downward displacement (n = 100) or a vacuum cycle autoclave (n = 100). Following autoclaving each band was inoculated into brain heart infusion culture broth and incubated at 37 degrees C for 5 days. None of the decontaminated bands exhibited growth after 5 days. It would appear that, using this methodology, there is little risk of a cross-infection hazard occurring with the re-use of previously tried-in and decontaminated molar bands.

  7. Interfacial Properties of Methylcelluloses: The Influence of Molar Mass

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    Pauline L. Nasatto

    2014-12-01

    Full Text Available The interfacial interactions of four methylcelluloses having the same average degree of substitution and distribution of methyl groups, but different molar masses, are studied at ambient temperature and at very low polymer concentrations. Firstly, the surface tension σ at the water/air interface is determined for the progressive addition of methylcellulose up to 100 mg/L; σ starts to decrease over 1 mg/L up to the critical aggregation concentration (CAC at 10 mg/L. The curves describing the influence of polymer concentration on σ are independent of the molar mass at equilibrium. Secondly, the adsorption of methylcellulose on silica particles is estimated from ζ-potential measurements. The data are interpreted in terms of an increase of the adsorbed layer thickness at the interface when the molar mass of methylcellulose increases. It is concluded that methylcellulose is adsorbed, forming trains and loops at the interface based on the equilibrium between surface free energy and solvent quality.

  8. 3-D diagnosis-assisted management of anomalous mandibular molar

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    Neelam Mittal

    2012-01-01

    Full Text Available 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.

  9. Quality of life following third molar removal under conscious sedation

    Science.gov (United States)

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

    2012-01-01

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

  10. Molar pregnancy with multiple organ dysfunction, an interesting

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    Purnima deb

    2011-01-01

    Full Text Available Successful management and cure of gestational trophoblastic disease [GTD, molar ] depends upon prompt, accurate diagnosis and institution of individualized, therapeutic modalities. Because Molar pregnancies encompasses multitude of clinical entities, each with myriad presentations, clinicians must remain alert to identify patients exhibiting signs and symptoms consistent with GTD [molar]. Armed with a high index of suspicion, physicians may target such individuals and launch the appropriate diagnostic barrage, leading to triage for treatment early in the course of the disease. The disease if not diagnosed early may lead to complication such as, acute respiratory distress, cardiac failure, liver and renal failure. Intracranial bleeding and seizures complicated with infection and coagulation failure may lead to death of these young women. Little data are available to assist in the counselling of women with diagnosis and compulsory follow up. Appropriate contraception should be discussed and advise given before discharge as they may get lost to follow up. These women should be informed of the elevated risk of developing malignant sequlae in future.

  11. Subcutaneous emphysema during third molar surgery: a case report.

    Science.gov (United States)

    Romeo, Umberto; Galanakis, Alexandros; Lerario, Francesco; Daniele, Gabriele Maria; Tenore, Gianluca; Palaia, Gaspare

    2011-01-01

    Extraction of third molars is the most common surgical procedure performed in oral surgery on a daily basis and, despite surgical skills and expertise, complications may occur. Complications observed during or after third molar removal may include pain, swelling, bleeding, infection, sinus perforation and nerve damage. Fortunately, with a proper management and a good surgical technique, the incidence of such events is low. Subcutaneous emphysema associated with dental extraction occurs when the air from the high-speed dental handpiece is forced into the soft tissue through the reflected flap and invades the adjacent tissues, leading to swelling, crepitus on palpation and occasionally spreading through the tissue spaces of the fascial planes. Although rare, iatrogenic subcutaneous emphysema can have serious and potentially life-threatening consequences. Care should be taken when using air-driven handpieces. The access of air into the facial tissues is not limited to tooth extractions, but may also occur through other portals of entrance, such as endodontically treated teeth, periodontium and lacerations of intraoral soft tissues. When subcutaneous emphysema occurs, it must be quickly diagnosed and properly managed to reduce the risk of further complications. This report presents a case of subcutaneous emphysema occurred during extraction of a mandibular third molar extraction with the use of an air turbine handpiece. Case management is described and issues relative to the diagnosis and prevention of this surgical complication are discussed.

  12. Evaluation of periodontal condition in intruded molars using miniscrews

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    Habib Ollah Ghanbari

    2015-12-01

    Full Text Available Introduction: The purpose of this preliminary study was to evaluate the periodontal condition of intruded molars in various phases of treatments. Methods: 30 patients with at least one overerupted upper first molar were selected. Upper molar bands with brackets were cemented. Two miniscrews were placed in the mesiopalatal and mesiobuccal aspect of the aforementioned teeth. A titanium molybdenum alloy (TMA spring was attached to the head of miniscrew in one end and ligated to the bracket in the other end to reach the predetermined force. Plaque index (PI, probing pocket depth (PPD, keratinized gingiva (KG, The distance between miniscrew (M.S and gingival level (GL, and bleeding on probing (BOP were recorded before loading and 1, 2, 3, 4 and 5 months post-loading .Results:  All patients completed the study and no complications were reported. Statistically significant intrusion (2.1 ± 0.9 mm was obtained during active treatment. Inserting miniscrews generally was presented with greater sulcus bleeding, plaque accumulation and plaque formation at follow-up visits. There was a statistically significant increase in PI, PPD and BOP indices. Furthermore, the results showed decrease in KG level and M.S to GL level. Conclusion: Miniscrews can provide a clinical benefit as an absolute anchorage device. However, keeping a good oral hygiene is essential to achieve ideal results, because the presence of miniscrews, as a foreign object in mouth, and intrusion force might be harmful for periodontal tissues

  13. 无水氯化锶的制备工艺研究%Preparation Technology of Anhydrous Strontium Chloride

    Institute of Scientific and Technical Information of China (English)

    邹兴武; 王树轩; 杨占寿; 王舒娅; 祁米香

    2012-01-01

    依托青海锶资源优势,以次等品碳酸锶和工业盐酸为原料,制备了无水氯化锶.并对除钡、除铁、除硫、脱水干燥等工艺进行了研究.产品能达到一般工业品的要求.氯化锶的制备不仅丰富我省锶产品的种类,而且增加了锶资源企业的抗风险能力.%Relying on the advantage of Qinghai strontium resources, the anhydrous strontium chloride was prepared by low-grade strontium carbonate and industrial hydrochloric acid. The process of removal of barium, sulfur and other impurities from low-grade strontium carbonate was studied,and evaporation,concentration , crystallization, filtering and drying processes were also investigated. The quality of products can reach the requirements of the general industrial. Preparation of strontium chloride, not only enrich the types of strontium products in Qinghai province,but also increase the ability of resiting risk of Strontium production enterprises.

  14. Crystal structure of barium perchlorate anhydrate, Ba(ClO42, from laboratory X-ray powder data

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    Jeonghoo H. Lee

    2015-06-01

    Full Text Available The previously unknown crystal structure of barium perchlorate anhydrate, determined and refined from laboratory X-ray powder diffraction data, represents a new structure type. The title compound was obtained by heating hydrated barium perchlorate [Ba(ClO42·xH2O] at 423 K in vacuo for 6 h. It crystallizes in the orthorhombic space group Fddd. The asymmetric unit contains one Ba (site symmetry 222 on special position 8a, one Cl (site symmetry 2 on special position 16f and two O sites (on general positions 32h. The structure can be described as a three-dimensional polyhedral network resulting from the corner- and edge-sharing of BaO12 polyhedra and ClO4 tetrahedra. Each BaO12 polyhedron shares corners with eight ClO4 tetrahedra, and edges with two ClO4 tetrahedra. Each ClO4 tetrahedron shares corners with four BaO12 polyhedra, and an edge with the other BaO12 polyhedron.

  15. Does the Preemptive Use of Oral Nonsteroidal Anti-inflammatory Drugs Reduce Postoperative Pain in Surgical Removal of Third Molars? A Meta-analysis of Randomized Clinical Trials.

    Science.gov (United States)

    Costa, Fábio Wildson Gurgel; Esses, Diego Felipe Silveira; de Barros Silva, Paulo Goberlânio; Carvalho, Francisco Samuel Rodrigues; Sá, Carlos Diego Lopes; Albuquerque, Assis Filipe Medeiros; Bezerra, Tácio Pinheiro; Ribeiro, Thyciana Rodrigues; Sá Roriz Fonteles, Cristiane; Soares, Eduardo Costa Studart

    2015-01-01

    The purpose of this study was to investigate the effectiveness of preemptive analgesia with nonsteroidal anti-inflammatory drugs (NSAIDs) in third-molar surgery. A PubMed literature search was conducted for articles restricted to the English language using the following terms (DeCS/MeSH) or combinations: analgesia, third molar, and preemptive. From a total of 704 articles, 6 (n=420 subjects) were selected. All studies presented a low risk of bias (Cochrane criteria) but exhibited high heterogeneity of methods. Two studies were excluded from the meta-analysis because they did not have adequate numeric values (dichotomous data) for the calculations. Preemptive analgesia showed no significant benefit (n=298, P=.2227, odds ratio: 2.30, 0.60-8.73) in reducing postoperative pain after removal of lower impacted third molars. However, there was a probable direct relationship between the effectiveness of NSAIDs in preemptive analgesia for removal of third molars and its selectivity for the cyclooxygenase-2 (COX-2). Preemptive analgesia did not have a significant effect in reducing postoperative pain after removal of lower impacted third molars. More homogeneous and well-delineated clinical studies are necessary to determine a possible association between NSAIDs' selectivity for COX-2 and treatment effectiveness.

  16. Molar Mass and Second Virial Coefficient of Polyethylene Glycol by Vapor Pressure Osmometry

    Science.gov (United States)

    Schwinefus, Jeffrey J.; Checkal, Caleb; Saksa, Brian; Baka, Nadia; Modi, Kalpit; Rivera, Carlos

    2015-01-01

    In this laboratory experiment, students determine the number-average molar masses and second virial coefficients of polyethylene glycol (PEG) polymers ranging in molar mass from 200 to 1500 g mol[superscript -1] using vapor pressure osmometry (VPO). Students assess VPO in relation to accurate molar mass calculations of PEG polymers. Additionally,…

  17. The origin of the lower fourth molar in canids, inferred by individual variation

    Directory of Open Access Journals (Sweden)

    Masakazu Asahara

    2016-11-01

    Full Text Available Background An increase in tooth number is an exception during mammalian evolution. The acquisition of the lower fourth molar in the bat-eared fox (Otocyon megalotis, Canidae, Carnivora, Mammalia is one example; however, its developmental origin is not clear. In some canids (Canidae, individual variation exist as supernumerary molar M4. This study focuses on the acquisition of the lower fourth molar in canids and proposes that the inhibitory cascade model can explain its origin. Methods Occlusal view projected area of lower molars was determined from 740 mandibles obtained from Canis latrans, Nyctereutes procyonoides, and Urocyon cinereoargenteus museum specimens. For each molar, relative sizes of molars (M2/M1 and M3/M1 scores affected by inhibition/activation dynamics during development, were compared between individuals with and without supernumerary molar (M4. Results Possession of a supernumerary molar was associated with significantly larger M2/M1 score in Canis latrans, M3/M1 score in Nyctereutes procyonoides, and M2/M1 and M3/M1 scores in Urocyon cinereoargenteus compared to individuals of these species that lacked supernumerary molars. Discussion We propose that, in canids, the supernumerary fourth molar is attributable to reduced inhibition and greater activation during molar development. In the bat-eared fox, altered inhibition and activation dynamics of dental development during omnivorous-insectivorous adaptation may be a contributing factor in the origin of the lower fourth molar.

  18. Solid Phase Synthesis of Anhydrous Zinc Borate from Zinc and Boron Oxide and Utilization as a Flame Retardant in Dye and Textile

    OpenAIRE

    AYAR, Barış; GÜRÜ, Metin; ÇAKANYILDIRIM, Çetin

    2014-01-01

    Durability of materials to flame and stability at high temperatures are very important in order to increase the field of use. Non-flammability is not the only requirement materials should not have toxic gas products during the burning, also. Anhydrous zinc borate was chosen as flame retardant due to its advantages, such as; light weight, high melting point, low thermal expansion, and intrinsic smoke suppressant and corrosion resistance properties. For the synthesis, metallic zinc and anhydrou...

  19. The use of anhydrous CeCl{sub 3} as a recyclable and selective catalyst for the acetalization of aldehydes and ketones

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Claudio C.; Mendes, Samuel R.; Ziembowicz, Francieli I. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Dept. de Quimica; Lenardao, Eder J.; Perin, Gelson [Universidade Federal de Pelotas (UFPel), RS (Brazil). Inst. de Quimica e Geociencias

    2010-07-01

    An efficient, clean, chemoselective and solvent-free method for the synthesis of ketone and aldehyde dimethyl acetals was developed using trimethyl orthoformate and commercially available anhydrous CeCl{sub 3} as a recyclable catalyst. The method is general and affords the protected carbonyl compounds in good yields and under mild conditions, including aryl and alkyl ketones and activated aldehydes. The catalyst could be utilised directly for 3 cycles, without significant loss of activity. (author)

  20. Two expedient ‘one-pot’ methods for synthesis of -aryl--mercaptoketones over anhydrous potassium carbonate or amberlyst-15 catalyst

    Indian Academy of Sciences (India)

    Chayan Guha; Rina Mondal; Rammohan Pal; Asok K Mallik

    2013-11-01

    Two expedient one-pot methods have been developed for synthesis of -aryl--mercaptoketones using acetophenones, benzaldehydes and thiols as starting materials. The methods involve microwave irradiation (5min) of 1:1 mixtures of acetophenones and benzaldehydes over neutral alumina supported anhydrous potassium carbonate or amberlyst-15 in the first step, and that is followed by addition of thiol to the resulting material and keeping at room temperature for 1.5 h.

  1. Determining the amount of anhydrous alcohol evaporated in vertical cylindrical tanks; Determinacao da quantidade de alcool etilico anidro evaporado em tanques cilindricos verticais

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Elcio Cruz de [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    In order to assess the anhydrous alcohol evaporated amount in vertical cylindrical tanks was developed a calculation methodology based on the rate of mass transfer of the product, the Reynolds number and the mass transfer coefficient. An Excel spreadsheet was prepared with data entry of the tank and physical and chemical properties of the product (temperature and density). For a temperature of 50 deg C, the volume evaporated reaches values of 0.8% by day. (author)

  2. Molar Absorptivities of Ultraviolet and Visible Bands of Ozone in Aqueous Solutions

    DEFF Research Database (Denmark)

    Hart, E.J.; Sehested, Knud; Holcman, J.

    1983-01-01

    The molar absorptivities of aqueous ozone solutions [.epsilon.(O3)] are reported for the wavelength ranges 190-300 nm and 350-900 nm. At the maxima of these bands, .epsilon.260(O3) = 3292 .+-. 70 M-1 cm-1 and .epsilon.590(O3) = 5.1 .+-. 0.1 M-1 cm-1. The analyses for ozone were carried out...... of aqueous O3 is compared with that of ozone gas....... by absorbance measurements of the gas at 253.7 nm and by oxidation of FeSO4 in H2SO4 solution followed by back-titration of excess Fe2+ with KMnO4. Spectrophotometric analysis of Fe3+ was also used at low ozone concentrations. A stoichiometric ratio, Fe3+/O3, of 1.996 .+-. 0.036 was found. The visible spectrum...

  3. Restauraciones cerámicas en molares jóvenes con endodoncia Ceramics restorations in young molars with endodontic

    OpenAIRE

    M. Urdaneta Quintero; L. Yánez de Meléndez; J. Álvarez Zárraga; M. Jimeno Jiménez; C. Soto Mestre

    2009-01-01

    Objetivo: Efectuar restauraciones cerámicas Cerec (feldespática y de dióxido de circonio) en molares jóvenes con endodoncia, para prevenir complicaciones en el aparato estomatognático por la pérdida de estos dientes. Material y métodos: Se describe la confección de restauraciones cerámicas a nivel de la zona molar mandibular derecha de un paciente del género femenino de 18 años de edad, a quien se le realizó radiografía periapical, por presentar dolor espontáneo en el lado derecho mandibular....

  4. The influence of excipients on the stability of the moisture sensitive drugs aspirin and niacinamide: comparison of tablets containing lactose monohydrate with tablets containing anhydrous lactose.

    Science.gov (United States)

    Du, J; Hoag, S W

    2001-01-01

    The purpose of this study is to test the hypothesis that in tablet formulations, moisture-sensitive drugs formulated with lactose monohydrate have the same stability as formulations containing anhydrous lactose, and to characterize the kinetics of niacinamide degradation in the solid state. Aspirin and niacinamide decomposition were used as indicators of stability. Aspirin and niacinamide tablets containing either lactose monohydrate or anhydrous lactose were separately investigated at different temperatures and relative humidities; the stability tests were done at 25 degrees C--60% RH, 40 degrees C--80% RH, 60 degrees C--60% RH, 60 degrees C--80% RH, and 80 degrees C--80% RH. Official U.S. Pharmacopeia methods were used for the aspirin and niacinamide assays. Statistical analysis showed that tablets containing lactose monohydrate have the same stability as tablets containing anhydrous lactose, which means that even though water is present in the crystal structure, the bound water does not influence the reaction rate. In addition, niacinamide degradation in the solid-state can be described by a third order rate equation.

  5. Lower Nitrous Oxide Emissions from Anhydrous Ammonia Application Prior to Soil Freezing in Late Fall Than Spring Pre-Plant Application.

    Science.gov (United States)

    Tenuta, Mario; Gao, Xiaopeng; Flaten, Donald N; Amiro, Brian D

    2016-07-01

    Fall application of anhydrous ammonia in Manitoba is common but its impact on nitrous oxide (NO) emissions is not well known. A 2-yr study compared application before freeze-up in late fall to spring pre-plant application of anhydrous ammonia on nitrous oxide (NO) emissions from a clay soil in the Red River Valley, Manitoba. Spring wheat ( L.) and corn ( L.) were grown on two 4-ha fields in 2011 and 2012, respectively. Field-scale flux of NO was measured using a flux-gradient micrometeorological approach. Late fall treatment did not induce NO emissions soon after application or in winter likely because soil was frozen. Application time did alter the temporal pattern of emissions with late fall and spring pre-plant applications significantly increasing median daily NO flux at spring thaw and early crop growing season, respectively. The majority of emissions occurred in early growing season resulting in cumulative emissions for the crop year being numerically 33% less for late fall than spring pre-plant application. Poor yield in the first year with late fall treatment occurred because of weed and volunteer growth with delayed planting. Results show late fall application of anhydrous ammonia before freeze-up increased NO emissions at thaw and decreased emissions for the early growing season compared to spring pre-plant application. However, improved nitrogen availability of late fall application to crops the following year is required when planting is delayed because of excessive moisture in spring.

  6. Anhydrate to hydrate solid-state transformations of carbamazepine and nitrofurantoin in biorelevant media studied in situ using time-resolved synchrotron X-ray diffraction

    DEFF Research Database (Denmark)

    Bøtker, Johan Peter; Rantanen, Jukka; Arnfast, Lærke

    2016-01-01

    with different biorelevant media, simulated fasted and fed state intestinal fluids containing bile salt and dioleoylphosphatidylcholine (DOPC) micelles, DOPC/sodium dodecyl sulfate (SDS) mixture, bile salt solution and water. Two anhydrate compounds (carbamazepine, CBZ and nitrofurantoin, NF) with different......Abstract Transformation of the solid-state form of a drug compound in the lumen of the gastrointestinal tract may alter the drug bioavailability and in extreme cases result in patient fatalities. The solution-mediated anhydrate-to-hydrate phase transformation was examined using an in vitro model...... analysis, PCA) and compared to those for nitrofurantoin (NF). The study showed that the solution-mediated phase transformation of CBZ anhydrate was remarkably faster in the DOPC/SDS medium compared to transformation in all the other aqueous dispersion media. The conversion time for CBZ anhydrate in water...

  7. Management of bilateral severely impacted mandibular second molars: a case report.

    Science.gov (United States)

    Manosudprasit, Montian; Wangsrimongkol, Tasanee; Pisek, Poonsak; Chantaramungkorn, Melissa

    2013-09-01

    Impaction of the mandibular second molar is relatively rare but when it occurs it may cause a clinical problem for orthodontist and oral surgeon. There are various treatment options to manage this condition depending on the degree of second molar inclination, the position of third molars, and the desired type of tooth movement. Here, a case of orthodontic uprighting of bilateral horizontal impaction of the lower second molars in a 17-years-old Thai female patient is presented. Correction of the impactions involved removal of the overlying third molars and use of full edgewise appliances with open NiTi-coil spring and super-elastic NiTi archwire.

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

    Science.gov (United States)

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

    2010-03-01

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

  9. Mandibular alveolar neurovascular bundle injury associated with impacted third molar surgery.

    Science.gov (United States)

    Ruga, Emanuele; Gallesio, Cesare; Boffano, Paolo

    2010-07-01

    Inferior alveolar neurovascular bundle (IANB) injury is one of the most common complications of third molar removal and involves important medicolegal issues. An accurate preoperative radiographic assessment of surgical difficulty is necessary to correctly plan the removal of impacted third molars and to estimate the risk of IANB injury. Therefore, the preoperative knowledge of the exact location of the third molar roots in relation to the mandibular canal is mandatory. A direct contact between the tooth and neurovascular bundle is suggested by a radiotransparent band across the roots of the impacted third molar on panoramic radiograph. We present the management of a patient with IANB damage associated with third molar surgery.

  10. Compensation trends of the angulation of first molars: retrospective study of 1403 malocclusion cases.

    Science.gov (United States)

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

    2014-09-01

    We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged 16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability.

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

  12. Assessment of the relationship between the maxillary molars and adjacent structures using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2012-09-15

    This study investigated the relationship between the roots of the maxillary molars and the maxillary sinus using cone beam computed tomography (CBCT), and measured the distances between the roots of the maxillary molars and the sinus floor as well as the thickness of the bone between the root and the alveolar cortical plate. The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars were examined using CBCT images. The vertical relationship of each root with the maxillary sinus was classified into four types on CBCT cross-sectional images. The distance between the sinus floor and root and the bone thickness between the root and alveolar cortical plate were measured. In the buccal roots of the maxillary molars, a root protruding into the sinus occurred most frequently. A root projecting laterally along the sinus cavity was most common in the palatal roots of the maxillary first molars. The mesiobuccal roots of the maxillary second molar were closest to the sinus. The mesiobuccal roots of the first molars were closest to the cortical plate. The relationship between the roots of the maxillary molars and the sinus differed between the buccal and palatal roots. A root protruding into the sinus occurred more frequent in the buccal roots of the maxillary molars. The mesiobuccal root of the maxillary second molar was closest to the maxillary sinus floor and farthest from the alveolar cortical plate.

  13. Modified distal shoe appliance for the loss of a primary second molar: a case report.

    Science.gov (United States)

    Dhull, Kanika Singh; Bhojraj, Nandlal; Yadav, Shweta; Prabhakaran, Sheeja Devi

    2011-01-01

    Preservation of primary teeth until their normal exfoliation plays a crucial role in preventive and interceptive dentistry. Premature loss of the primary second molar prior to the eruption of the permanent first molar in the absence of the primary second molar can lead to mesial movement and migration of the permanent molar before and during its eruption. In such cases, an intra-alveolar type of space maintainer to guide the eruption of the permanent first molar is indicated. In certain cases, however, the conventional design is not practical. This paper describes a new design for distal shoe appliances in cases of primary second molar loss prior to the eruption of the permanent mandibular first molar.

  14. Exodoncia del tercer molar: Factores que determinan complejidad

    Directory of Open Access Journals (Sweden)

    Ivan Manotas Arevalo

    2014-06-01

    Full Text Available ResumenUno de los procedimientos más frecuentes en el campo de la Cirugía Oral es la exodoncia, o extracción dental. La prevención y la promoción de hábitos saludables dentro de los que se cuenta la práctica del cepillado dental, uso de dentífricos, hilo dental y enjuagatorios bucales, además de visitas periódicas de control a especialistas y odontólogos generales e higienistas bucales ha conllevado a una reducción en la perdida de estructuras dentarias por causa de la caries y las periodontopatìas. Sin embargo se mantiene alto el número de exodoncias indicadas por falta de espacio en la estructura de los maxilares para la erupción dental, así como alteraciones en la posición y angulacion de los órganos dentales sobre su eje que impide una adecuada ubicación logrando que se indique su extracción. Dentro de la serie dental los órganos dentarios más frecuentemente afectados por este tipo de alteraciones son los terceros molares. También se mencionan que son esos mismos dientes los que acusan mayor grado de complejidad para realizar el procedimiento de exodoncia, y los que causan mayor grado de morbilidad posquirúrgica en el paciente, con un número mayor de complicaciones y su severidad, descritas en la literatura. (Duazary 2008; 141-147. Este artículo pretende analizar los factores que determinan complejidad en la exodoncia del tercer molar a partir de una revisión bibliografía y comparación de ésta.AbstractOne of the most frequent procedure used in the field of Oral Surgery is extracted, or tooth extraction. The prevention and promoting healthy habits in mind that the practice of brushing teeth, use of toothpastes, mouthwashes and dental floss mouth, in addition to regular monitoring visits to specialists and general dentists and oral hygiene has led to a reduction in the loss of structures caused by tooth decay and periodontal pathology. However remains high number of extractions indicated by lack of space in the

  15. An equation for calculating the volumetric ratios required in a ligation reaction.

    Science.gov (United States)

    Cranenburgh, R M

    2004-08-01

    The ligation of two DNA fragments to create a new plasmid DNA molecule is a key reaction in molecular biology. Where the fragment lengths and concentrations are known, existing equations allow the desired relative molar ratio to be calculated, but this must then be related to the required volumes. Further calculations are then necessary if the maximum available volume is to consist of DNA solutions. The equation presented here allows the simple calculation of volumes of DNA solutions required to obtain a desired molar insert-to-vector ratio, and these can comprise all of the available volume in a ligation if required, thus maximising the yield of the recombinant plasmid.

  16. Low to Extremely Low Water Abundances Measured in Nominally Anhydrous Minerals in Mafic to Granitic Apollo Rock Clasts

    Science.gov (United States)

    Simon, J. I.; Christoffersen, R.; Wang, J.; Alexander, C. M. O'D.; Mills, R. D.; Hauri, E. H.

    2017-01-01

    Lunar sample-based volatile studies have focused on assessing the inventory and distribution of water in the Moon. Some have focused on the relatively young mare basalts and pyroclastic glasses, which result from partial melting of the relatively young lunar mantle. Less certain is the water inventory for the oldest materials available, which have the greater potential to record the earliest history of volatiles in the Moon (and thus provide evidence for the "wet" vs. "dry" accretion hypotheses of the Earth-Moon system. Studies of volatiles in ancient lunar rocks have largely focused on apatite. One recent FTIR (Fourier Transform Infrared Radiometer) study of plagioclase reported a relatively "wet" (approximately 320 parts per million) magma for primordial ferroan anorthosites (FANs). Another, a NanoSIMS study of alkali feldspar, reported a "wet" (approximately 1 weight percentage) felsic magma, but due to the differentiation processes required for silicic magmatism in the lunar crust, predicted an essentially "dry" (less than 100 parts per million) bulk Moon. Thus, despite evidence that appears to complicate the early "dry" Moon paradigm, there is no apparent unanimity among the measurements, even those on apatite. This disparity is clearly seen by the order of magnitude different water estimates for lunar "alkali-rich suite rocks" (Fig. 1). Some of the apparent differences may be explained by recent improvements in the apatite-based water estimates that better account for relative compatibilities of OH-, Cl, and F. In the present work, we seek to expand our understanding of the volatile abundances in early formed lunar magmas, their source reservoirs, and to address the potential role that felsic magmas play on the lunar hydrogen budget over time by employing NanoSIMS analysis of nominally anhydrous minerals.

  17. Lingual and inferior alveolar nerve injuries after third molar removal.

    Science.gov (United States)

    Donoff, R Bruce; Fagin, Adam P

    2013-01-01

    Trigeminal nerve injury is a rare, but serious complication of a common procedure, which results in a clinically relevant problem that deserves attention. The emergence of microsurgical repair of trigeminal injury has provided clinicians with treatment options for patients who experience persistent neurosensory deficits. The area of microsurgical repair of trigeminal nerves is now in its adolescence. While great strides have been made in the field since its conception, it is certain that a new generation of oral and maxillofacial surgeons wil bring further progress to the field. In the future, better quantitative sensory testing methods, more accurate imaging modalities, and advances in surgical technique will certainly improve the management of patients with impacted third molars. As clinicians, every day we are confronted with the management of impacted third molars. It is important to evaluate each patient individually with an appropriate clinical and radiographic exam. Every patient should be informed of the relative risks and benefits of third molar removal and a joint decision should be reached between the clinician and patient regarding ideal treatment. However, even with ideal management, complications will occur. If a patient does present with signs of a nerve injury the clinician should carefully document the neurosensory deficit and monitor the patient over time. If the patient exhibits a significant sensory deficit for more than one month a referral for evaluation to a tertiary care center capable of surgical repair of the injury is recommended. The occurrence of a "trigger" or Tinel's like sign is improtant as an indication for surgery but may not occur for a month after injury.

  18. Cameriere's third molar maturity index in assessing age of majority.

    Science.gov (United States)

    Galić, Ivan; Lauc, Tomislav; Brkić, Hrvoje; Vodanović, Marin; Galić, Elizabeta; Biazevic, Maria Gabriela Haye; Brakus, Ivan; Badrov, Jozo; Cameriere, Roberto

    2015-07-01

    Estimation of chronological age of an individual is one of the main challenges in forensic science. Legally to be able to treat a person as a minor or an adult, it is necessary to determine whether their age of majority (if they are older or younger than 18, in most countries). Methods for estimating age are especially important when an individual in question lacks personal documents or other means of identification. As the dental age differs in various populations, the aim of this study was to evaluate applicability of third molar method for assessing age of majority in Croatia. Cameriere's third molar maturity index (I3M) value of 0.08, measured by the open apices of the teeth, was verified in sample of 1336 panoramic images aged between 14 and 23 years. Chronological age gradually decreased as I3M increased in both genders. Males showed statistically significant advanced maturation when I3M was between 0.0 and 0.3 value. The results indicate that the sensitivity of the test for 0.08 value was 84.3% (95%CI 80.6%, 87.5%) for females and 91.2% (95%CI 88.7%, 93.1) for males. Specificity was 95.4% (95%CI 92.5%, 97.5%) and 91.9% (95%CI 88.8%, 94.3%). The proportions of accurately classified males were 88.8% and that of females 91.5%. The estimated post-test probabilities, of individuals, in other word the probability that a Croatian individual with an I3Mthird molar maturity index should be used as a determinant of the age of majority in Croatia.

  19. Incidence of cystic changes in impacted lower third molar

    Directory of Open Access Journals (Sweden)

    Shridevi R Adaki

    2013-01-01

    Full Text Available Objective: To assess the incidence of cystic changes in the impacted lower third molar (ILTM in which the pericoronal (follicular space is less than 2.5 mm as measured from the radiograph. The relationship between the cystic changes and patient′s age, sex, and angular position and contact of ILTM with adjacent tooth was also evaluated. Materials and Methods: Follicular space less than 2.5 mm as measured from the panoramic radiograph was included in the study. A total of 73 tissue samples collected during the extraction ILTM were examined histopathologically. Then the data were analyzed for associations with age, sex, angular position, and contact of the ILTM with an adjacent tooth. Results: There were 37 male and 36 female patients, age ranging from 17 to 35 years (mean 23.95 years. Out of 73 specimens, 17 (23.3% showed cystic changes; among them 16 (22.1% showed dentigerous cysts and 1 (1.2% showed odontogenic keratocysts. Most of the cystic changes occurred in the 26-30 year age range. The cystic changes showed male predominance but could not gain statistical significance. The relationship between cystic changes and angular position was statistically significant (P < 0.05. Higher probability was found in distoangular positioned ILTM. The relationship between cystic changes and communication of ILTM with the second molar was not statistically significant. Conclusion: Incidence of cystic changes in ILTM justifies extraction of the impacted tooth associated with symptoms. The decision to extract or not to extract impacted third molar should be individualized, rather than generalized.

  20. [Molar incisor hypomineralization (MIH)--a literature review].

    Science.gov (United States)

    Gotler, M; Ratson, T

    2010-04-01

    MIH was defined by Weerheijm (2001) as "hypomineralisation of systemic origin of 1-4 permanent first molars, frequently associated with affected incisors". The prevalence of MIH varies between 2.8% and 25%, dependent upon the study. At their sixth congress in 2003, The European Association of pediatric dentistry defined criteria for diagnosis of the phenomena. It included the presence of demarcated opacity, posteruptive enamel breakdown, atypical restoration, extracted molar due to MIH and unerupted teeth. According to the teeth involved and to the time of the crown formation, researches focused on environmental and systemic conditions as possible reasons for MIH.The etiologies were divided into five groups: Exposure to environmental contaminants, pre/peri and neonatal problems, exposure to fluoride, common childhood illnesses and medically compromised children. The clinical implications include highly sensitive teeth, difficulty to achieve adequate anesthesia, behavioral problems and anxiety, rapid progression of caries and the esthetic implications. A six step approach to management was described suggested: risk identification, early diagnosis, remineralization and desensitization, prevention of caries and posteruption breakdown, restorations and extractions and finally maintenance. Restoring an affected molar can vary from adhesive intra coronal restorations (resin composite is the material of choice) to extra coronal restorations (e.g. preformed metal crown). Esthetic solutions to affected incisors may include microabrasion (that shows little improvement) and resin composite or porcelain veneer. The key for a successful treatment is early diagnosis, intense follow up and usage of remineralizating agents as soon as the teeth erupt. There is still need for further research to clarify the etiological factors and improve the durability of restoration in affected teeth.

  1. Irregular Periapical Radiopacity in Mandibular Premolars and Molars

    Directory of Open Access Journals (Sweden)

    S. Aravind Warrier

    2014-01-01

    Full Text Available Increased deposition of cementum is observed in a wide number of both benign and malignant conditions. Many cases are often diagnosed during routine examination as an incidental finding. Diagnosing correctly without confusing it with other similarly appearing lesions, thus avoiding subjecting the patient to unnecessary investigations and stress, is of prime importance. We report one such case, where the patient presented with the routine complaint of a painful tooth, during the investigation of which he was also diagnosed with hypercementosis affecting the mandibular second premolars and molars bilaterally. The literature review reveals that not many cases of hypercementosis are frequently reported.

  2. Pericoronitis, deep fascial space infections, and the impacted third molar.

    Science.gov (United States)

    Litonjua, L S

    1996-01-01

    Patients consulting the Philippine General Hospital Dentistry Department for management of impacted mandibular third molars were studied for the presence of pericoronits and deep fascial space infections. 18% of total cases presented an infection, while 13% presented with pericoronitis. 11% presented with deep fascial infection of which 72% were secondary to pericoronitis. A radiographic evaluation showed the vertical angulation (68%) with the highest portion at or above the occlusal level (70%) associated the most with pericoronits. The potential of pericoronitis developing to a deep space infection should always be considered.

  3. Human age estimation combining third molar and skeletal development.

    Science.gov (United States)

    Thevissen, P W; Kaur, J; Willems, G

    2012-03-01

    The wide prediction intervals obtained with age estimation methods based on third molar development could be reduced by combining these dental observations with age-related skeletal information. Therefore, on cephalometric radiographs, the most accurate age-estimating skeletal variable and related registration method were searched and added to a regression model, with age as response and third molar stages as explanatory variable. In a pilot set up on a dataset of 496 (283 M; 213 F) cephalometric radiographs, the techniques of Baccetti et al. (2005) (BA), Seedat et al. (2005) (SE), Caldas et al. (2007) and Rai et al. (2008) (RA) were verified. In the main study, data from 460 (208 F, 224 M) individuals in an age range between 3 and 26 years, for which at the same day an orthopantogram and a cephalogram were taken, were collected. On the orthopantomograms, the left third molar development was registered using the scoring system described by Gleiser and Hunt (1955) and modified by Köhler (1994) (GH). On the cephalograms, cervical vertebrae development was registered according to the BA and SE techniques. A regression model, with age as response and the GH scores as explanatory variable, was fitted to the data. Next, information of BA, SE and BA + SE was, respectively, added to this model. From all obtained models, the determination coefficients and the root mean squared errors were calculated. Inclusion of information from cephalograms based on the BA, as well as the SE, technique improved the amount of explained variance in age acquired from panoramic radiographs using the GH technique with 48%. Inclusion of cephalometric BA + SE information marginally improved the previous result (+1%). The RMSE decreased with 1.93, 1.85 and 2.03 years by adding, respectively, BA, SE and BA + SE information to the GH model. The SE technique allows clinically the fastest and easiest registration of the degree of development of the cervical vertebrae. Therefore, the choice of

  4. Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns

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    Roopak Bose Carlos

    2013-01-01

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

  5. Peripheral facial nerve paralysis after upper third molar extraction.

    Science.gov (United States)

    Cakarer, Sirmahan; Can, Taylan; Cankaya, Burak; Erdem, Mehmet Ali; Yazici, Sinem; Ayintap, Emre; Özden, Ali Veysel; Keskin, Cengizhan

    2010-11-01

    Peripheral facial nerve paralysis (PFNP) after mandibular interventions has been reported in the literature. In most cases, paralysis begins immediately after the injection of the mandibular anesthesia, and duration of facial weakness is less than 12 hours. However, there are few documented cases of PFNP after maxillary dental or surgical procedures. A variety of mechanisms have been associated to PFNP, including viral reactivation, demyelination, edema, vasospasm, and trauma. The purpose of this presentation was to report a rare case of facial paralysis that occurred after an upper third molar extraction. The cause of the PFNP and the importance of the multidisciplinary approach in the management are emphasized.

  6. Prevalence of cervical enamel projection in human molars

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    Maria Regina Lima de Souza

    2014-01-01

    Full Text Available Introduction : One of the developmental anomalies of dental enamel is cervical enamel projection (CEP. The aim of this study was to assess the prevalence of CEP in maxillary and mandibular human teeth. Materials and Methods: A total of 234 human molars obtained from the tooth bank of the State University of Amazonas were used in the present study. CEP was classified as Grade 0 (absence of projection, Grade I (discrete extension of cementoenamel junction toward the furcation, Grade II (closer to furcation without invasion, and Grade III (extending to the furcation area. The evaluation was performed using macroscopic inspection of teeth faces (buccal, lingual/palatal, mesial, and distal with at least one-third of the crown on each face. Results: It was found that 17.1% of the teeth evaluated had CEP, but neither of the projections occurred on the proximal faces. Higher prevalence of CEP was found on the buccal faces and the most commonly grade of CEP found was Grade I (10.3%. Conclusions: It may be concluded that CEP occurs more frequently in mandibular molars and its diagnosis is extremely important since these projections may difficult bacterial plaque removal, leading to an inflammatory process and unnecessary endodontic treatment.

  7. Supplemental root in a mandibular first molar: a rarity

    Directory of Open Access Journals (Sweden)

    Poonam Mahajan

    2011-04-01

    Full Text Available Anatomic variations are common in human dentition. A clear understanding of these variations is very important for success of endodontic treatment. A dentist should be aware of these anatomic variations as this can affect the treatment outcome. A case of endodontic therapy is presented in which inability to locate an anatomically rare supplemental canal of a three rooted mandibular first molar resulted in treatment failure. A 21-year-old female reported with pain and swelling in relation to lower right first molar. An intra oral periapical radiograph revealed 3 roots; the first canal of the mesial root and a canal of one of the distal roots were found to be treated endodontically, which were infraobturated but the canal of the 2nd distal root had not been treated. The radiograph revealed periapical radiolucency and widening of periodontal space. Prior to starting the endodontic treatment the clinician must be aware of the anatomic variations in tooth pulp morphology and also the importance of preoperative radiographs cannot be underscored.

  8. Comparison of Primary Molar Crown Dimensions with Stainless Steel Crowns in a Sample of Iranian Children.

    Science.gov (United States)

    Afshar, Hossein; Kamali Sabeti, Arghavan; Shahrabi, Mahdi

    2015-01-01

    Background and aims. Due to anatomic variation in tooth anatomy between populations, this study compared the buccolingual (BL) and mesiodistal (MD) dimensions of primary molars with those of stainless steel crowns (SSCs) in anIranian population. Materials and methods. Impressions were taken from both dental arches of children, and casts were poured. Teeth with caries, restoration, hypoplasia or other dental anomalies were excluded. 216 primary molars were selected and divided into 4 groups of 54 each (maxillary and mandibular first and second primary molars). MD/BL dimensions were measured using a digital caliper with 0.01 mm precision on casts and SCCs (3M brand). Data were assessed using paired t-test, post hoc test and ANOVA. P < 0.05 was considered statistically significant. Results. The MD dimension of the lower first molar SSC and the BL dimension of the lower second molar SSC had the least difference with the corresponding values of the respective teeth. The MD dimension of the upper second molar SSC and the BL dimension of the upper first molar SSC had the greatest difference with the corresponding values in the respective teeth. Comparison of the two different brands of SSCs for the upper first molar revealed that both types had significant differences with the teeth in terms of both MD (P = 0.0) and BL (P = 0.0) dimensions. Conclusion. In the studied population, best adaptation was seen in second lower molars and the least adaptationswere seen in first and second upper molars.

  9. Controlled Aspect Ratios of Gold Nanorods in Reduction-Limited Conditions

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    Jong-Yeob Kim

    2011-01-01

    Full Text Available Aspect ratios of gold nanorods have been finely modified in reduction-limited conditions via two electrochemical ways: by changing the amount of a growth solution containing small gold clusters in the presence of already prepared gold nanorods as seeds or by changing electrolysis time in the presence or absence of a silver plate. While the atomic molar ratio of gold in the growth solution to gold in the seed solution is critical in the former method, the relative molar ratio of gold ions to silver ions in the electrolytic solution is important in the latter way for the control of the aspect ratios of gold nanorods. The aspect ratios of gold nanorods decrease with an increase of electrolysis time in the absence of a silver plate, but they increase with an increase of electrolysis time in the presence of a silver plate.

  10. Radiolucency below the crown of mandibular horizontal incompletely impacted third molars and acute inflammation in men with diabetes

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    Minoru Yamaoka

    2009-05-01

    Full Text Available Minoru Yamaoka, Yusuke Ono, Masahide Ishizuka, Kouichi Yasuda, Takashi Uematsu, Kiyofumi FurusawaOral and Maxillofacial Surgery, Matsumoto Dental University, Shiojiri, Nagano 399-0781, JapanAbstract: Although mandibular third molar has a high risk of infection extending any complications, the influence of diabetes on radiolucency and acute inflammation in pericoronitis remains unclear. The present study was to evaluate whether radiolucency below the crown is related to acute inflammation in mandibular horizontal incompletely impacted third molars and to review the records of 140 men more than 45 years with and without diabetes. The odds ratio of exhibiting acute inflammation was 3.38 (95% CI: 1.13–10.16, p < 0.05 and that of exhibiting severe acute inflammation was 15.38 (95% CI: 3.56–66.49, p < 0.0001, indicating an association of acute pericoronitis in diabetes. The frequency of radiolucency below the crown and below the root in diabetics was similar to that in nondiabetics. However, the odds ratio of exhibiting both radiolucency below the crown and acute inflammation under the diabetic condition was 4.85 (95% CI: 1.60–14.73, p < 0.01, whereas that of diabetics showing both radiolucency below the root and acute inflammation was 0.46 (95% CI: 0.06–3.74, p = 0.74. Radiolucency below the crown and acute inflammation were associated with diabetes, but that below root and acute inflammation were not associated with diabetes, indicating that the region below the crown carries susceptibility to acute pericoronitis, whereas the periodontium shows a protective effect against acute pericoronitis.Keywords: radiolucency, acute inflammation, mandible, third molar, diabetes, periodontium

  11. Sorption of pure N2O to biochars and other organic and inorganic materials under anhydrous conditions

    Science.gov (United States)

    Cornelissen, Gerard; Rutherford, David W.; Arp, Hans Peter H.; Dorsch, Peter; Kelly, Charlene N.; Rostad, Colleen E.

    2013-01-01

    Suppression of nitrous oxide (N2O) emissions from soil is commonly observed after amendment with biochar. The mechanisms accounting for this suppression are not yet understood. One possible contributing mechanism is N2O sorption to biochar. The sorption of N2O and carbon dioxide (CO2) to four biochars was measured in an anhydrous system with pure N2O. The biochar data were compared to those for two activated carbons and other components potentially present in soils—uncharred pine wood and peat—and five inorganic metal oxides with variable surface areas. Langmuir maximum sorption capacities (Qmax) for N2O on the pine wood biochars (generated between 250 and 500 °C) and activated carbons were 17–73 cm3 g–1 at 20 °C (median 51 cm3 g–1), with Langmuir affinities (b) of 2–5 atm–1 (median 3.4 atm–1). Both Qmaxand b of the charred materials were substantially higher than those for peat, uncharred wood, and metal oxides [Qmax 1–34 cm3 g–1 (median 7 cm3 g–1); b 0.4–1.7 atm–1 (median 0.7 atm–1)]. This indicates that biochar can bind N2O more strongly than both mineral and organic soil materials. Qmax and b for CO2 were comparable to those for N2O. Modeled sorption coefficients obtained with an independent polyparameter—linear free-energy relationship matched measured data within a factor 2 for mineral surfaces but underestimated by a factor of 5–24 for biochar and carbonaceous surfaces. Isosteric enthalpies of sorption of N2O were mostly between −20 and −30 kJ mol–1, slightly more exothermic than enthalpies of condensation (−16.1 kJ mol–1). Qmax of N2O on biochar (50000–130000 μg g–1 biochar at 20 °C) exceeded the N2O emission suppressions observed in the literature (range 0.5–960 μg g–1 biochar; median 16 μg g–1) by several orders of magnitude. Thus, the hypothesis could not be falsified that sorption of N2O to biochar is a mechanism of N2O emission suppression.

  12. Molar Dua Sulung Sebagai Salah Satu Pencetus Maloklusi Ditinjau Secara Radiografis (Laporan Kasus

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    Gimawati Muljono

    2015-10-01

    Full Text Available Pengetahuan mengenai kehilangan dini gigi molar-2 sulung sebagai penyebab miringnya gigi molar-1 tetap dan berkurangnya ruangan tempat erupsi gigi kaninus dan premolar, sudah lama diketahui. Dari penelusuran pustaka ternyata masih banyak faktor yang efeknya sama dan penyebabnya gigi molar-2 sulung yang kurang disadari dan belum mendapat perhatian sepenuhnya. Faktor-faktor tersebut adalah : anatomis, karies, ankilose, dan iatrogenik, yang efek lanjutnya bahkan dapat sampai menimbulkan maloklusi. Makalah ini akan mengemukakan suatu kasus, sehubungan dengan keadaan gigi molar-2 sulung yang dapat menjadi salah satu faktor penyebab maloklusi ditinjau secara radiografis dengan foto panoramik dan cephalometri. Ramalan maloklusi gigi geligi tetap dapat dilihat dari proyeksi gambar pergeseran gigi-gigi, kontak oklusi bidang terminal permukaan distal mahkota gigi molar-2 sulung, hubungan kontak gigi molar-1 tetap di foto pasien.

  13. Correlation of acute pericoronitis and the position of the mandibular third molar.

    Science.gov (United States)

    Leone, S A; Edenfield, M J; Cohen, M E

    1986-09-01

    Acute pericoronitis is a painful, debilitating infection that is most commonly found among young adults with erupting mandibular third molars. Prophylactic removal of third molars to prevent this disease has been advocated, but this procedure requires an accurate description of the third molar at highest risk for this infection. Clinical and radiographic measurements were compared in 25 diseased subjects and 109 normal subjects. Of 10 variables significantly related to the presence of acute pericoronitis, stepwise discriminant analysis selected 4 variables that produced a canonical correlation coefficient of 0.71. In clinical terms, these variables described the tooth at highest risk for acute pericoronitis as a fully erupted, vertical mandibular third molar that is in contact with the adjacent second molar, at or above the occlusal plane, and partially encapsulated by soft or hard tissues. Prophylactic treatment of these third molars is highly recommended.

  14. Etiology, Classification and Management of Ectopic Eruption of Permanent First Molars.

    Science.gov (United States)

    Hsiao, Chu-Chun; Boynton, James R

    2016-01-01

    Ectopic eruption of a permanent tooth involves abnormal resorption of a portion or all of the adjacent primary tooth. Among the most commonly ectopically erupted teeth are the permanent first molars. Ectopically erupting molars may require intervention to allow for full eruption, or they may spontaneously self-correct and erupt into occlusion. Decisions regarding the necessity of intervention, its ideal timing, and intervention type are multifactorial. Treatment options for the ectopically erupting permanent first molar include the elastomeric separator, brass wire, pre-fabricated clip separator, custom made appliances (Humphrey appliance, Halterman appliance), or extraction of the primary molar. Early intervention when indicated can ensure proper full eruption of the permanent first molar and prevent mesial angulation, arch perimeter loss, tooth impaction and ankylosis. Two cases are described that manage ectopic eruption of the permanent first molar.

  15. Adulteration determination of the anhydrous ethanol fuels samples with methanol; Determinacao de adulteracao por metanol em amostras de alcool etilico anidro combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Eduardo; Mota, Claudio J.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica]. E-mail: eduardoc@dh.com.br; cmota@iq.ufrj.br

    2003-07-01

    A fast test made to evidence an adulteration of anhydrous ethanol with methanol consist in mixing the alcohol with gasoline. A pink coloration indicates the adulteration by methanol. Samples of gasoline A, ethanol and high purity methanol were mixed at different proportions, but no color change was observed. On the other hand, samples of gasoline A, ethanol and formaldehyde 40% showed the characteristic pink coloration, for methanol adulteration. This result indicates that the test is sensible to the presence of formaldehyde, probably presence as impurity or formed by oxidation of the methanol. A lower detection limit of 4.8% of formaldehyde in the alcohol was determined. (author)

  16. Inorganic-organic hybrid membranes with anhydrous proton conduction prepared from 3-aminopropyltriethoxysilane and sulfuric acid by the sol-gel method.

    Science.gov (United States)

    Tezuka, Teruaki; Tadanaga, Kiyoharu; Hayashi, Akitoshi; Tatsumisago, Masahiro

    2006-12-27

    Inorganic-organic hybrid membranes with anhydrous proton conduction were prepared from 3-aminopropyltriethoxysilane and H2SO4 by the sol-gel method. The membrane has a unique structure: a hexagonal phase formed by the stacking of rodlike polysiloxanes with ion complexes of ammonium groups and HSO4- extruded outside. The membranes showed high conductivity of 2 x 10-3 S cm-1 at 200 degrees C under dry atmosphere. In the membrane, protons probably migrate through the outside of the rodlike polysiloxanes along hydrogen-bond chains formed among HSO4- anions.

  17. Stability of molar relationship after non-extraction Class II malocclusion treatment

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    Darwin Vaz de Lima

    2013-04-01

    Full Text Available OBJECTIVE: This study aimed to evaluate the stability of molar relationship after non-extraction treatment of Class II malocclusion. METHODS: The sample comprised 39 subjects (16 females, 23 males with initial Class II malocclusion treated with no extractions, using fixed appliances. Mean age at the beginning of treatment was 12.94 years, at the end of treatment was 15.14 years and at post-retention stage was 21.18 years. Mean treatment time was 2.19 years and mean time of post-treatment evaluation was 6.12 years. To verify the influence of the severity of initial Class II molar relationship in stability of molar relationship, the sample was divided into two groups, one presenting a ½-cusp or ¾-cusp Class II molar relationship, and the other with full-cusp Class II molar relationship. In dental casts from initial, final and postretention stages, molar, first and second premolars and canine relationships were measured. Data obtained were analyzed by dependent ANOVA, Tukey and Pearson's correlation tests, as well as independent t test between the two groups divided by severity of initial molar relationship. RESULTS: There was a non-statistically significant 0.12 mm relapse of molar relationship. The initial severity of Class II molar relationship was not correlated to relapse in the post-retention period. When compared, the two groups showed no difference in relapse of molar relationship. CONCLUSION: It was concluded that correction of Class II molar relationship is stable and initial severity does not influence relapse of molar relationship.

  18. Partial molar volume of L-Valine in water under high pressure

    Science.gov (United States)

    Sawamura, Seiji

    2013-06-01

    Partial molar volume of L-valine in water was estimated up to 400 MPa from pressure coefficient of the solubility of the solute and molar volume of solid valine. The former was measured in a previous paper and the latter was measured in this article using a piston-cylinder typed cell. The partial molar volume increased with pressure and a maximum was observed around 250 MPa. It was compared with other amino acids.

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

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    Mohanavelu Deepalakshmi

    2012-01-01

    Full Text Available 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.

  20. Fate of third molar in line of mandibular angle fracture - Retrospective study

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    Preetha Balaji

    2015-01-01

    Conclusion: The present study fails to identify any concrete factors that would predict the failure of the retained third molar that were involved in the line of mandibular fractures. The proof presented here, especially with low complication rates indicate that all impacted third molar along the line of fracture be removed and unless necessary, the partially erupted teeth would also be extracted. In such a situation, the rate of infection and survival of the third molar would have been entirely different.

  1. The origin of the lower fourth molar in canids, inferred by individual variation

    OpenAIRE

    Masakazu Asahara

    2016-01-01

    Background An increase in tooth number is an exception during mammalian evolution. The acquisition of the lower fourth molar in the bat-eared fox (Otocyon megalotis, Canidae, Carnivora, Mammalia) is one example; however, its developmental origin is not clear. In some canids (Canidae), individual variation exist as supernumerary molar M4. This study focuses on the acquisition of the lower fourth molar in canids and proposes that the inhibitory cascade model can explain its origin. Methods Occl...

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

    OpenAIRE

    Jung, Yun-Hoa; Cho, Bong-Hae

    2013-01-01

    Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent ...

  3. Age estimation using development of third molars in South Indian population: A radiological study

    Science.gov (United States)

    Priyadharshini, K. Indra; Idiculla, Jose Joy; Sivapathasundaram, B.; Mohanbabu, V.; Augustine, Dominic; Patil, Shankargouda

    2015-01-01

    Aim: To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A–H) method of Demirjian et al. in Chennai population of South India. Materials and Methods: A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P < 0.05 was considered as the level of significance. Results: The results showed that the mean age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P < 0.05). Conclusion: There are differences indicating that maxillary and mandibular third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization. PMID:25984465

  4. Single implant in the mandibular molar region of edentulous patient.

    Science.gov (United States)

    Zhai, Jun-Jiang; Wen, Cai; Teng, Ming-Hua; Liang, Xing

    2013-09-01

    Implant-retained overdentures are a valid treatment option for edentulous patients, especially for patients with severe alveolar ridge atrophy. A central single implant is considered adequate to retain an overdenture in the edentulous mandible. However, for some patients, there is no sufficient bone height, or width in the interforaminal region of the mandible for insertion of the implant. This case report illustrates that the insertion of a single implant in the mandibular molar region might stabilize the prosthesis, and might improve the oral health-related quality of life and chewing function. A Locator attachment was used in this case to retain the overdenture. The one-year clinical results are promising. However, long-term clinical results and randomized clinical trials are needed before this method can be widely used in clinical application.

  5. Restoration of primary molars using a new "compomer" material.

    Science.gov (United States)

    Swift, E J; Vann, W F

    1995-10-01

    The primary advantages of glass ionomer restorative materials are adhesion to tooth structure and release of fluoride. A new material has been recently introduced for the restoration of cervical lesions and Class I defects in primary teeth. The material combines the properties of glass ionomers with the advantages of a single-component, light-activated composite resin and is known as a "compomer". This new material contains two resins, instead of the acidic polymers found in conventional glass ionomers. The restorative material releases fluoride and can be infected directly into the cavity. With its own bonding agent, the compomer offers a simple and relatively rapid technique. The learning objective of this paper is to describe the utilization of the new restorative material in conjunction with a bonding agent to restore conservative cavity preparations in primary molars. Two clinical cases are used to illustrate the presentation.

  6. Indirect pulp capping in primary molar using glass ionomer cements

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    Murtia Metalita

    2014-12-01

    Full Text Available Background: Indirect pulp capping in primary teeth, however, is more rarely conducted than permanent teeth, since it thought to have low impact and most suggestion is for taking caries lesion aggressively on primary teeth. Purpose: The study was aimed to evaluate the subjective complaint, clinical symptom, and radiographic appearance of indirect pulp capping treatment using glass ionomers cements in primary molar. Methods: Sixteen children in range of age 6 to 8 years old, who visited Clinic of Pediatric Dentistry Universitas Airlangga Dental Hospital, Surabaya Indonesia, were the subject of study. They had one occlusal dental caries on one side of maxillary or mandibular primary molar with the diagnose of pulpitis reversible. The experimental group, had indirect pulp capping treatment with glass ionomer cements (GC Fuji VII®, while the control group, had indirect pulp capping treatment with calcium hydroxide (Metapaste. Each group was filled with GC Fuji IX® as permanent restoration. After one week, one month, and three months later, the observations were made on subjective complaint, clinical symptom, and radiographic appearance. Results: The results showed no subjective complaint such as pain or problem on mastication; no negative clinical symptoms such as pain on palpation, gingivitis or periodontitis, and abnormal tooth mobility; no negative radiographic appearance such as pathological apical radioluscency, internal or external resorbtion, and change of ligament periodontal widthafter the treatment. Conclusion: The study suggested that indirect pulp capping treatment using glass ionomer cement materials on primary teeth might be considered to be the treatment choice.Latar belakang: Indirect pulp capping pada gigi sulung lebih jarang dilakukan dibandingkan gigi permanen, karena dianggap memiliki dampak yang rendah dan sebagian besar menyarankan untuk mengambil lesi karies secara agresif pada gigi sulung. Tujuan: Penelitian ini bertujuan

  7. Calculations of Molar Fractions of the IPR C78 Fullerenes

    Science.gov (United States)

    Uhlík, Filip; Slanina, Zdeněk

    2002-10-01

    There are five isolated-pentagon-rule (IPR) satisfying isomers of C78. In contradiction to theoretical predictions, only three isomers were observed in experiments and the fourth one was not identified until very recently. In this work we calculate structural and energetic data of the five IPR C78 fullerenes, namely we optimized their geometries with the B3LYP density-functional method using the standard 4-31G basis set (B3LYP/4-31G), calculated separation energies at the B3LYP/6-311G* level (B3LYP/6-311G*//B3LYP/4-31G), estimated energies of low lying electronic states with the ZINDO semiempirical method and calculated harmonic vibrational frequencies with the semiempirical SAM1 method. From the obtained data we constructed chirality respecting isomeric partition functions and evaluated molar fractions in the equilibrium isomeric mixture for a wide temperature interval.

  8. Molar Volume Analysis of Molten Ni-Al-Co Alloy by Measuring the Density

    Institute of Scientific and Technical Information of China (English)

    XIAO Feng; FANG Liang; FU Yuechao; YANG Lingchuan

    2004-01-01

    The density of molten Ni-Al-Co alloys was measured in the temperature range of 1714~1873K using a modified pycnometric method, and the molar volume of molten alloys was analyzed. The density of molten Ni-Al-Co alloys was found to decrease with increasing temperature and Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys increases with increasing Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys shows a negative deviation from the linear molar volume.

  9. Prevalence and Pattern of Third Molar Impaction; A retrospective study of radiographs in Oman

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    Samira M. Al-Anqudi

    2014-08-01

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

  10. Periodontal considerations in the use of bonds or bands on molars in adolescents and adults.

    Science.gov (United States)

    Boyd, R L; Baumrind, S

    1992-01-01

    This longitudinal study compared the periodontal status of bonded and banded molars in 20 adult and 40 adolescent patients before, during and after treatment with fixed orthodontic appliances. Plaque accumulation (measured by the Plaque Index), gingival inflammation (measured by the Gingival Index and the bleeding tendency), and pocket depth were assessed by one examiner at sites along the mesio-buccal line angle of the maxillary right first molar and the mandibular left first molar. Assessments were made immediately prior to the placement of fixed appliances (pretreatment), at 1, 3, 6, 9, 12 and 18 months after appliances were placed; and 3 months after appliances were removed (posttreatment). Loss of attachment between the pretreatment and posttreatment visits also was determined. At pretreatment, no significant differences were found in gingival inflammation between maxillary and mandibular banded and bonded molars. During treatment, both maxillary and mandibular banded molars showed significantly (p less than 0.05) greater gingival inflammation and plaque accumulation than did bonded molars. Three months after appliance removal, the maxillary molars that had been banded continued to show significantly more gingival inflammation and loss of attachment than did the maxillary molars that had been bonded. When all banded and bonded teeth were grouped by patient age, mean values for plaque accumulation and gingival inflammation in the maxillary molar regions were significantly greater for adolescents than for adults.

  11. Do antibiotics reduce the frequency of surgical site infections after impacted mandibular third molar surgery?

    Science.gov (United States)

    Susarla, Srinivas M; Sharaf, Basel; Dodson, Thomas B

    2011-11-01

    Surgical removal of impacted third molars remains the most common procedure performed by oral and maxillofacial surgeons. Given the abundance of host bacteria within the operative sites, surgical site infections are among the most common complications of third molar removal, with an estimated frequency of 1% to 30%. In this setting, significant controversy has surrounded the use of prophylactic antibiotics in the surgical management of impacted third molars. This article provides a comprehensive review of the available data on antibiotic prophylaxis in impacted third molar surgery and offers specific recommendations on antibiotic use.

  12. Mandibular Third Molar Impaction: Review of Literature and a Proposal of a Classification

    Directory of Open Access Journals (Sweden)

    Gintaras Juodzbalys

    2013-06-01

    Full Text Available Objectives: The purpose of present article was to review impacted mandibular third molar aetiology, clinical anatomy, radiologic examination, surgical treatment and possible complications, as well as to create new mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results.Material and Methods: Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular third molar, impacted mandibular third molar, inferior alveolar nerve injury third molar, lingual nerve injury third molar. The search was restricted to English language articles, published from 1976 to April 2013. Additionally, a manual search in the major anatomy and oral surgery journals and books was performed. The publications there selected by including clinical and human anatomy studies.Results: In total 73 literature sources were obtained and reviewed. Impacted mandibular third molar aetiology, clinical anatomy, radiographic examination, surgical extraction of and possible complications, classifications and risk factors were discussed. New mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results was proposed. Conclusions: The classification proposed here based on anatomical and radiological impacted mandibular third molar features is promising to be a helpful tool for impacted tooth assessment as well as for planning for surgical operation. Further clinical studies should be conducted for new classification validation and reliability evaluation.

  13. Unusual anatomical detection of a third molar in the infratemporal fossa.

    Science.gov (United States)

    Corega, C; Vaida, L; Festila, D; Bertossi, D

    2013-01-01

    Third molar presence in the infratemporal fossa is a rare event and it has been reported previously only two times in the literature, except for the cases which arise from complications occurring during the extraction of the impacted upper third molar. Due to the presence of important vessel bundles and nerves in this area, third molar removal requires a correct surgical management in order to avoid many possible serious side effects. We report an unusual case of upper third molar detected in the infratemporal fossa, which has been thoroughly investigated radiologically and removed through a safe surgical approach.

  14. The evolution of molar occlusion in the Cercopithecidae and early Catarrhines.

    Science.gov (United States)

    Kay, R F

    1977-03-01

    Those Eocene prosimians which are possible catarrhine ancestors have four blade-like crests on each lower molar. Each crest shears in sequence across two upper molar crests. Occluding crests are concavely curved to hold the foods being sheared. Each of two medial lower molar crests bordering the principal crushing surface shear past single upper molar crests at about the same time the lateral lower molar crests contact the second rank of upper molar crests. Grinding and crushing areas are restricted to hypoconid, trigonid, and protocone surfaces. Oligocene catarrhine molars have increased crushing-grinding capacities and maintained but modify their shearing. As the crushing surface of the protocone expands and a crushing hypocone is added, the "second rank" upper molar shearing crests are functionally reduced. At the same time medial crests are increasingly emphasized so that the total shearing capacity remains virtually unchanged. Marginal shearing blades are straight edged; leading edges of occluding blades are set at different angles to the occlusal plane so that blades contact at only one point at any given time. Early Primates have separate crushing basins surrounded by shearing blades. Catarrhines tend to link explanding crushing surfaces anteroposteriorly into a continuous surface between all molars. A cladistic analysis based on both new and previously recognized characters indicates that: 1. Apidium may be more closely related to Aegyptopithecus than to Parapithecus; 2. cercopithecids are derived from a Parapithecus-related stock; 3. Oreopithecus could equally well have come from an Apidium or Aegyptopithecus stock.

  15. Assessment of maxillary third molars with panoramic radiography and cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept.of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2015-12-15

    This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT). A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images.

  16. An unusual occurrence of bilaterally geminated mandibular second premolars resulting in premolar molarization: A case report

    Directory of Open Access Journals (Sweden)

    A V Rajesh Ebenezar

    2013-01-01

    Full Text Available Gemination refers to an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root. This report describes a rare case of bilateral gemination of permanent mandibular second premolar tooth giving rise to molarization of premolars. The mesiodistal width of these teeth is similar to mandibular molars, but the cervicoocclusal width is lesser than that of the molar tooth. This paper also discusses the potential orthodontic, periodontal, and endodontic complications of premolar molarization.

  17. Compression Ratio Adjuster

    Science.gov (United States)

    Akkerman, J. W.

    1982-01-01

    New mechanism alters compression ratio of internal-combustion engine according to load so that engine operates at top fuel efficiency. Ordinary gasoline, diesel and gas engines with their fixed compression ratios are inefficient at partial load and at low-speed full load. Mechanism ensures engines operate as efficiently under these conditions as they do at highload and high speed.

  18. Offer/Acceptance Ratio.

    Science.gov (United States)

    Collins, Mimi

    1997-01-01

    Explores how human resource professionals, with above average offer/acceptance ratios, streamline their recruitment efforts. Profiles company strategies with internships, internal promotion, cooperative education programs, and how to get candidates to accept offers. Also discusses how to use the offer/acceptance ratio as a measure of program…

  19. Financial Key Ratios

    Directory of Open Access Journals (Sweden)

    Tănase Alin-Eliodor

    2014-08-01

    Full Text Available This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  20. Specialized ratio analysis.

    Science.gov (United States)

    Wyer, J C; Salzinger, F H

    1983-01-01

    Many common management techniques have little use in managing a medical group practice. Ratio analysis, however, can easily be adapted to the group practice setting. Acting as broad-gauge indicators, financial ratios provide an early warning of potential problems and can be very useful in planning for future operations. The author has gathered a collection of financial ratios which were developed by participants at an education seminar presented for the Virginia Medical Group Management Association. Classified according to the human element, system component, and financial factor, the ratios provide a good sampling of measurements relevant to medical group practices and can serve as an example for custom-tailoring a ratio analysis system for your medical group.

  1. Relationship between lower third molar and mandibular canal; Preoperative evaluation using CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Itou, Masaki; Miyagishima, Toshio; Onizuka, Hiroyuki (Fujieda City Shida General Hospital, Shizuoka (Japan)); Takagi, Norio

    1994-01-01

    The mandibular canal is often closely related to the lower third molars. During the surgical removal of the third molar, the inferior alveolar nerve in the canal is sometimes damaged leading to impaired sensation in the lower lip. This is one of the most unpleasant postoperative complications. The buccolingual relationship between the lower third molar and the mandibular canal cannot be diagnosed by ortho-pantomography although preoperative evaluation must be carried out radiologically. In present study, the relationship was determined by using CT scan. Forty-seven lower third molars of 35 patients were evaluated preoperatively by CT scan. The mandibular canal of all cases overlapped with the third molar on ortho-pantomography. CT scan was taken in two ways. The first was the Tragion-Menton plane which was nearly parallel to the canal at the apex of the third molar. The second was the plane of the axis of the third molar. Axial CT scan was taken when the third molar erupted horizontally, and coronal CT scan was done when the molar erupted vertically. CT scan examination exactly revealed the position of the mandibular canal in relation to the root of the third molar. The canal was located buccally to the roots in 55 percent of cases, apicobuccally in 6 percent, apically in 23 percent, apicolingually in 6 percent, lingually in 2 percent, and between roots in 6 percent. The results of the present study were consistent with previous reports. In 12 cases, the inferior alveolar neurovascular bundle was visible during operation. It was visible in only 2 of 22 cases when the canal was located buccally. It was visible, on the other hand, in all cases in which the canal was located apicolingually, lingually, and between roots. It also tended to be visible when the canal overlapped more strongly with the third molar on preoperative ortho-pantomography. (author).

  2. A extração de segundos molares superiores para o tratamento da Classe II Extraction of upper second molars for treatment of Angle Class II malocclusion

    Directory of Open Access Journals (Sweden)

    Maurício Barbieri Mezomo

    2010-06-01

    Full Text Available Este trabalho tem por objetivo apresentar uma abordagem alternativa para o tratamento ortodôntico das más oclusões de Classe II. Através de uma revisão da literatura, verificou-se que a extração de segundos molares superiores demonstrou ser uma alternativa viável para o tratamento desse tipo de má oclusão. Essa opção terapêutica possibilita maior rapidez na distalização dos primeiros molares com menor necessidade de cooperação por parte do paciente. Porém, a análise do grau de formação, posição intraóssea e morfologia do terceiro molar deve ser cuidadosamente realizada para proporcionar o correto posicionamento do mesmo no lugar do segundo molar extraído. Dois casos clínicos apresentarão a sequência do diagnóstico e tratamento com essa mecânica, exibindo resultados adequados dos pontos de vista funcional e estético.The purpose of this article is to present an alternative approach to the orthodontic treatment of Angle Class II malocclusion. According to a literature review it was observed that the extraction of upper second molars has proven to be a viable alternative for the treatment of this type of malocclusion. This therapeutic option enables faster first molar retraction and requires less patient compliance. However, the level of development, intraosseous position and morphology of the third molar should be carefully evaluated to ensure its correct positioning in place of the extracted second molar. Two clinical case reports will demonstrate that the sequence of diagnosis and treatment used with this mechanics yields satisfactory functional and aesthetic results.

  3. Corticosteroids use in controlling pain, swelling and trismus after lower third molar surgery use in controlling pain, swelling and trismus after lower third molar surgery

    OpenAIRE

    2011-01-01

    Objectives: A study is made of corticosteroid use in controlling pain, swelling and trismus after lower third molar surgical removal. Material and methods: A Medline search and review was made of all randomized and controlled clinical trials on the effects of corticosteroids upon pain, swelling and trismus after lower third molar surgery. The review was limited to those studies published in the last 10 years. Of the 20 initially considered articles, 6 were finally excluded....

  4. Ringwoodite growth rates from olivine with ~75 ppmw H2O: Metastable olivine must be nearly anhydrous to exist in the mantle transition zone

    Energy Technology Data Exchange (ETDEWEB)

    Du Frane, Wyatt L. [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Atmospheric, Earth and Energy Division; Sharp, Thomas G. [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration; Mosenfelder, Jed L. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Geological and Planetary Sciences; Leinenweber, Kurt [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration

    2013-04-15

    It has been previously demonstrated that as little as 300 ppmw H2O increases wadsleyite and ringwoodite growth rates to magnitudes that are inconsistent with the metastable olivine hypothesis. To further test this hypothesis, we present new ringwoodite growth rate measurements from olivine with ~75 ppmw H2O at 18 GPa and 700, 900, and 1100 °C. These growth rates are nearly identical to those from olivine with ~300 ppmw H2O, and significantly higher than those from nominally anhydrous olivine. We infer that transformation of olivine with 75-300 ppmw H2O is primarily enhanced by hydrolytic weakening of reaction rims, which reduces the elastic strain-energy barrier to growth. We present a new method for fitting nonlinear nominally anhydrous data, to demonstrate that reduction of growth rates by elastic strain energy is an additional requirement for metastable olivine. In conclusion, based on previous thermokinetic modeling, these enhanced growth rates are inconsistent with the persistence of metastable olivine wedges into the mantle transition zone. Metastable persistence of olivine into the mantle transition-zone would therefore require < 75 ppmw H2O.

  5. Scientific Opinion on the safety and efficacy of betaine anhydrous as a feed additive for all animal species based on a dossier submitted by Danisco Animal Nutrition

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-05-01

    Full Text Available Glycine betaine (betaine acts as a methyl group donor in transmethylation reactions in organisms. Betaine occurs in numerous vertebrate tissues as an osmolyte, ensuring osmoprotection. Betaine is safe for piglets at the maximum supplementation rate of 2 000 mg/kg complete feed with a margin of safety below 5. This conclusion is extended to all pigs and extrapolated to all animal species and categories. The use of betaine as a feed additive up to a supplementation rate of 2 000 mg/kg complete feed is unlikely to pose concerns for consumer safety. Users’ inhalation exposure to betaine is expected to be minimal. Betaine anhydrous should be considered irritant to skin, eyes and mucous membranes and a skin sensitiser. It is likely to cause skin sensitisation. The supplementation of feed with betaine anhydrous does not pose a risk to the environment. Betaine has the potential to become efficacious in all animal species and categories when administered via feed or water for drinking. The FEEDAP Panel made some recommendations on (i introduction of a maximum content for supplemental betaine in complete feed and water for drinking; (ii avoidance of simultaneous use of betaine in feed and water for drinking; and (iii avoidance of simultaneous inclusion of betaine and choline chloride in premixtures.

  6. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...... and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....

  7. Micro-CT analyses of apical enlargement and molar root canal complexity

    DEFF Research Database (Denmark)

    Markvart, Merete; Darvann, Tron Andre; Larsen, Per

    2012-01-01

    AIM: To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical enlargement in molar teeth and to quantify and visualize spatial details of instrumentation efficacy in root canals of different complexity. METHODOLOGY: Maxillary and mandibular molar teeth wer...

  8. Functional approach to a Class II patient with upper first molar impaction

    Directory of Open Access Journals (Sweden)

    Giacomo D′Orlandi

    2014-01-01

    Full Text Available The lack of the left first molar maxillary and the left second molar maxillary, caused respectively by impaction and agenesis is a very rare case, which determines an important occlusal imbalance and asymmetrical mandible movement. A gnatologic and functional orthodontic approach were planned to improve the retrognathic mandible and the muscular activity using kinesiograph and electromyography.

  9. Functional approach to a Class II patient with upper first molar impaction

    OpenAIRE

    Giacomo D′Orlandi; Lorenzo Raguzzi; Efisio Defraia; Felicita Pierleoni

    2014-01-01

    The lack of the left first molar maxillary and the left second molar maxillary, caused respectively by impaction and agenesis is a very rare case, which determines an important occlusal imbalance and asymmetrical mandible movement. A gnatologic and functional orthodontic approach were planned to improve the retrognathic mandible and the muscular activity using kinesiograph and electromyography.

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

    Science.gov (United States)

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

    2014-08-01

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

  11. Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults.

    Science.gov (United States)

    Karadayi, Beytullah; Kaya, Ahsen; Kolusayın, Melek Ozlem; Karadayi, Sükriye; Afsin, Hüseyin; Ozaslan, Abdi

    2012-11-01

    Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15-23 years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22 years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars' eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.

  12. Hypomineralized second primary molars: Prevalence data in Dutch 5-year-olds

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Schuller, A.A.; Weerheijm, K.L.; Veerkamp, J.S.J.

    2008-01-01

    The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar i

  13. Hypomineralized second primary molars : prevalence data in Dutch 5-year-olds

    NARCIS (Netherlands)

    Elfrink, M E C; Schuller, A A; Weerheijm, K L; Veerkamp, J S J

    2008-01-01

    The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar i

  14. Validity of scoring caries and primary molar hypomineralization (DMH) on intraoral photographs

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Veerkamp, J.S.J.; Aartman, I.H.A.; Moll, H.A.; ten Cate, J.M.

    2009-01-01

    AIM: The aims of this study were to assess whether intraoral photographs could be used to score caries and hypomineralization on primary molars (Using adapted Molar Incisor Hypomineralization (MIH)-criteria), and also to assess the reliability and validity in 3-7 year-old Dutch children of these sco

  15. Hypomineralized second primary molars: prevalence data in Dutch 5-year-olds

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Schuller, A.A.; Weerheijm, K.L.; Veerkamp, J.S.J.

    2008-01-01

    The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar i

  16. Morphology and chemical composition of dentin in permanent first molars with the diagnose MIH

    NARCIS (Netherlands)

    Heijs, Suzanne C. B.; Dietz, Wolfram; Noren, Jorgen G.; Blanksma, Nynke G.; Jalevik, Birgitta

    2007-01-01

    The purpose of this investigation was to study the morphology and distribution of some inorganic elements in dentin in first permanent molars from children with Molar-Incisor Hypomineralization (MIH). Sixty four tooth sections from thirty two children were examined in polarized light. Fifteen repres

  17. Evaluation of telemedicine systems for impacted third molars diagnosis

    Directory of Open Access Journals (Sweden)

    Duka Miloš

    2009-01-01

    Full Text Available Background/Aim. In the last twenty years significant advances have been made in the fields of information and telecommunication technology in health care applications, with a positive impact on the health care practice. The need for remote diagnosis and planning of interventions is of special importance in military health care, and health management of immobile persons, and those with special needs. In cases such as these, availability of specialist health care is mainly limited by geographic and financial factors. The aim of this study was to investigate practical usability of telemedicine approaches in everyday management of oral surgery patients in terms of reliability of established diagnosis and indications for oral surgery treatment of the third molars. Methods. Our experimental randomized study enrolled 432 randomly selected patients of both genders, aged 20 to 87 years, undergoing panoramic radiography for some reason in the Centre for Dental Radiography in Belgrade. In addition to radiography, photographs of the face and mouth cavity were taken. These images were uploaded to the web server specially dedicated to the study purposes, and then transmitted to teledentists, i.e. oral surgeons, who made remote diagnoses. Diagnostic agreement was determined by way of the Cohen's kappa coefficient, and diagnostic sensitivity (SE, specificity (SP, and effectiveness (EFF were also established. Statistical significance was determined and comparisons performed by using the z-test, and testing of non-parametric characteristics by using the McNemar's χ2 test for p = 0.05 significance cut-off. Results. The results obtained by analyzed images and diagnostic assessment of the clinical diagnosis (kappa = 0.99, SE = 99%, SP = 99%, EFF = 99%, for 95% CI indicate an almost complete diagnostic agreement. The differences in diagnosis were not statistically significant. Conclusion. Diagnostic assessment of the clinical diagnosis of impacted or semi

  18. [Orthodontic partial disimpaction of mandibular third molars prior to surgical extraction].

    Science.gov (United States)

    Derton, Nicolà; Perini, Alessandro; Giordanetto, José; Biondi, Giovanni; Siciliani, Giuseppe

    2009-06-01

    Odontodysplasia of the third molars is a relatively common anomaly. The frequent complications associated with this disorder very often constitute an indication for extraction of the third molar. This surgical treatment can damage the lower alveolar nerve and/or trigger distal bone loss of the second molar, thus jeopardizing the future status of the periodontium. The author presents two case studies treated exclusively with miniscrews with no dental anchorage in order to achieve partial eruption of the third molar moving it away from the lower alveolar nerve and to avoid unwanted impact on other teeth. Following this procedure, the third molar was extracted without complications. In conclusion, this approach can offer an alternative to surgical treatment alone in cases where the proximity of tooth and nerve poses a significant risk.

  19. Biodentine Pulpotomy in Mature Permanent Molar: A Case Report

    Science.gov (United States)

    2016-01-01

    Irreversible pulpitis is the most common reason for endodontic treatment in primary and permanent teeth. Root canal therapy and extraction are the two viable and most documented treatment options for the same. Studies with regards to management of mature permanent teeth with carious exposure and treatment with vital pulp therapies such as adult permanent tooth pulpotomy are scarce. However, permanent tooth pulpotomy with the new calcium-silicate based cements (Mineral Trioxide Aggregate and Biodentine) can help preserve the tooth pulp vitality and promote healing and repair foregoing the more invasive root canal therapy procedure. A 12-year old male patient with irreversible pulpitis in right mandibular first permanent molar was treated with complete coronal pulpotomy with placement of Biodentine in the pulp chamber and a full coronal coverage using stainless steel crown. Clinical and radiographic examinations were performed at three, six, twelve and eighteen months. At the end of 18 months, the patient was completely asymptomatic and the tooth was free of any clinical and radiographic signs of inflammation and infection. PMID:27630966

  20. MTA pulpotomy of human permanent molars with irreversible pulpitis.

    Science.gov (United States)

    Eghbal, Mohammad Jafar; Asgary, Saeed; Baglue, Reza Ali; Parirokh, Masoud; Ghoddusi, Jamileh

    2009-04-01

    The histological success of mineral trioxide aggregate (MTA) pulpotomy for treatment of irreversible pulpitis in human teeth as an alternative treatment was investigated in this study. Fourteen molars which had to be extracted were selected from patients 16-28 years old. The selection criteria include carious pulp exposure with a history of lingering pain. After isolation, caries removal and pulp exposure, MTA was used in pulpotomy treatment. Patients were evaluated for pain after 24 h. Two patients were lost from this study. Twelve teeth were extracted after 2 months and were assessed histologically. Recall examinations confirmed that none of the patients experienced pain after pulpotomy. Histological observation revealed that all samples had dentin bridge formation completely and that the pulps were vital and free of inflammation. Although the results favour the use of MTA as a pulpotomy material, more studies with larger samples and a longer recall period are suggested to justify the use of MTA for treatment of irreversible pulpitis in human permanent teeth.

  1. Biodentine Pulpotomy in Mature Permanent Molar: A Case Report.

    Science.gov (United States)

    Soni, Harleen Kaur

    2016-07-01

    Irreversible pulpitis is the most common reason for endodontic treatment in primary and permanent teeth. Root canal therapy and extraction are the two viable and most documented treatment options for the same. Studies with regards to management of mature permanent teeth with carious exposure and treatment with vital pulp therapies such as adult permanent tooth pulpotomy are scarce. However, permanent tooth pulpotomy with the new calcium-silicate based cements (Mineral Trioxide Aggregate and Biodentine) can help preserve the tooth pulp vitality and promote healing and repair foregoing the more invasive root canal therapy procedure. A 12-year old male patient with irreversible pulpitis in right mandibular first permanent molar was treated with complete coronal pulpotomy with placement of Biodentine in the pulp chamber and a full coronal coverage using stainless steel crown. Clinical and radiographic examinations were performed at three, six, twelve and eighteen months. At the end of 18 months, the patient was completely asymptomatic and the tooth was free of any clinical and radiographic signs of inflammation and infection.

  2. Molar crown inner structural organization in Javanese Homo erectus.

    Science.gov (United States)

    Zanolli, Clément

    2015-01-01

    This contribution investigates the inner organizational pattern (tooth tissue proportions and enamel-dentine junction morphology) of seven Homo erectus permanent molar crowns from the late Lower-early Middle Pleistocene Kabuh Formation of the Sangiran Dome (Central Java, Indonesia). The previous study of their external characteristics confirmed the degree of time-related structural reduction occurred in Javanese H. erectus, and also revealed a combination of nonmetric features which are rare in the Lower and early Middle Pleistocene dental record, but more frequently found in recent humans. In accordance with their outer occlusal morphology, the specimens exhibit a set of derived internal features, such as thick to hyperthick enamel, an incomplete expression of the crest patterns at the enamel-dentine junction (EDJ) level, a sharp EDJ topography. As a whole, these features differ from those expressed in some penecontemporaneous specimens/samples representing African H. erectus/ergaster and H. heidelbergensis, as well as in Neanderthals, but occur in recent human populations. Further research in virtual dental paleoanthropology to be developed at macroregional scale would clarify the polarity and intensity of the intermittent exchanges between continental and insular Southeast Asia around the Lower to Middle Pleistocene boundary, as well as should shed light on the still poorly understood longitudinal evolutionary dynamics across continental Asia.

  3. Experience versus complication rate in third molar surgery

    Directory of Open Access Journals (Sweden)

    Al-Khawalde Mohammed

    2006-05-01

    Full Text Available Abstract 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, several variables were recorded including age, gender, radiographic position of extracted teeth, treating surgeon, duration of surgery and postoperative complications. Results Analysis of the data revealed some differences in the incidence of complications produced by the specialists SD and OMFS residents. The main statistically relevant differences were increase the incidences of trismus, nerve paraesthesia, alveolar osteitis and infection in the resident-treated group, while the specialist-treated group showed higher rates of post-operative bleeding. Conclusion The higher rate of postoperative complications in the resident-treated group suggests that at least some of the complications might be related to surgical experience. Further work needs to compare specialists of training programmes with different years of experience, using large cross – sectional studies.

  4. Prediction of Molar Volumes of the Sudanese Reservoir Fluids

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    A. A. Rabah

    2010-01-01

    Full Text Available This paper provided important experimental PVT data of the Sudanese reservoir fluids. It includes composition analysis of 11 mixtures and about 148 PVT data points of constant mass expansion (CME tests at pressures below the bubble point. The datasets are compared with eight equations of state (EOS, namely, Peng Robinson (PR, Soave-Redlich-Kwong (SRK, Lawal-Lake-Silberberg (LLS, Adachi-Lu-Sugie (ALS, Schmidt-Wenzel (SW, Patel-Teja (PT, Modified-Nasrifar-Moshfeghian (MNM, and Harmens-Knapp (HK. The results of comparison reveals that, with the exception of PR and ALS EOSs, all other EOSs yield consistently a higher average absolute percent deviation (AAPD in the prediction of molar volume; it exceeds 20% by all mixtures. The grand average AAPD of all mixtures is 17 and 16 for PR and ALS, respectively. ALS is selected to represents the mixtures. It is modified by replacing the coefficient (Ωb1 of the parameter (b1 in the dominator of repulsive term by that of PR. This procedure enhanced the accuracy of ALS by 30 to 90% for individual mixtures and the grand average AAPD is significantly reduced from 16 to about 7.

  5. Molar incisor hypomineralization in HIV-infected children and adolescents.

    Science.gov (United States)

    Andrade, Natália Silva; Pontes, Alessandra Silva; de Sousa Paz, Hélvis Enri; de Moura, Marcoeli Silva; Moura, Lúcia de Fátima Almeida de Deus; Lima, Marina de Deus Mourade

    2017-01-01

    The objective was to determine the prevalence of molar incisor hypomineralization (MIH) among individuals between 7 and 15 years old infected or noninfected with human immunodeficiency virus (HIV). The study was conducted with 33 HIV-infected individuals (study group; SG) and 66 non-HIV-infected schoolchildren (control group; CG), paired by gender and age. Data collection was based on medical records (SG), a questionnaire for caregivers and oral examination for diagnosis of MIH (European Academy of Pediatric Dentistry criteria) and caries (DMFT index and ICDAS). Data were analyzed with Mann-Whitney, chi-square, and Fisher's exact tests and logistic regression. In SG, MIH (45.5%) and caries (87.9%) had higher prevalence. MIH was associated with use of protease inhibitors in SG (OR: 2.14; 95% CI: 1.21 to 3.77) and incubator need in CG (OR: 2.80; 95% CI: 1.71 to 9.10). HIV-infected patients had a higher prevalence of MIH and dental caries in the permanent dentition.

  6. Ratios of Normal Variables

    Directory of Open Access Journals (Sweden)

    George Marsaglia

    2006-05-01

    Full Text Available This article extends and amplifies on results from a paper of over forty years ago. It provides software for evaluating the density and distribution functions of the ratio z/w for any two jointly normal variates z,w, and provides details on methods for transforming a general ratio z/w into a standard form, (a+x/(b+y , with x and y independent standard normal and a, b non-negative constants. It discusses handling general ratios when, in theory, none of the moments exist yet practical considerations suggest there should be approximations whose adequacy can be verified by means of the included software. These approximations show that many of the ratios of normal variates encountered in practice can themselves be taken as normally distributed. A practical rule is developed: If a < 2.256 and 4 < b then the ratio (a+x/(b+y is itself approximately normally distributed with mean μ = a/(1.01b − .2713 and variance 2 = (a2 + 1/(b2 + .108b − 3.795 − μ2.

  7. Ratios of Normal Variables

    Directory of Open Access Journals (Sweden)

    George Marsaglia

    2006-05-01

    Full Text Available This article extends and amplifies on results from a paper of over forty years ago. It provides software for evaluating the density and distribution functions of the ratio z/w for any two jointly normal variates z,w, and provides details on methods for transforming a general ratio z/w into a standard form, (a+x/(b+y , with x and y independent standard normal and a, b non-negative constants. It discusses handling general ratios when, in theory, none of the moments exist yet practical considerations suggest there should be approximations whose adequacy can be verified by means of the included software. These approximations show that many of the ratios of normal variates encountered in practice can themselves be taken as normally distributed. A practical rule is developed: If a < 2.256 and 4 < b then the ratio (a+x/(b+y is itself approximately normally distributed with mean μ = a/(1.01b - .2713 and variance σ2 = (a2 + 1/(b2 + .108b - 3.795 μ2.

  8. Corticoesteroides y cirugía del tercer molar inferior: Revisión de la literatura Corticoesteroids and impacted lower third molar surgery: Literature review

    Directory of Open Access Journals (Sweden)

    I Prieto

    2005-10-01

    Full Text Available El objetivo de este trabajo es buscar la evidencia disponible con respecto al uso, justificación, efectos secundarios y eficacia de corticosteroides para reducir el dolor e inflamación postoperatorios en la extracción quirúrgica de terceros molares. Queremos saber si en pacientes adultos, es la prescripción de antiinflamatorios esteroideos además de los antiinflamatorios no esteroideos (AINES, en comparación con la administración única de AINES, más efectiva para mejorar, aliviar o eliminar los síntomas de inflamación y dolor después de la extracción quirúrgica de terceros molares inferiores. En la revisión de la literatura se ha utilizando la base de datos Medline con las palabras clave "esteroides" y "terceros molares" o "Muelas del juicio" y "Cirugía". La búsqueda fue limitada también a estudios en humanos, lengua inglesa y revistas dentales.The aim of this study is searching the available evidence with respect to the use, justification, side effects and efficacy of corticosteroids in reducing pain and swelling after the surgical extraction of impacted lower third molars. We want to investigate if steroidal anti-inflammatories prescription in addition to non-steroidal anti-inflammatory drugs (NSAID, when compared with the exclusive administration of NSAID, is more effective improving, relieving or eradicating symptoms of swelling and pain after the extraction of the impacted lower third molar. We have utilize in this literature review the Medline database with the keywords "steroids" and "Third molars" or "wisdom molars" and "surgery". The search was also limited to humans, English and dental journals.

  9. Partial molar volume and partial molar compressibility of four homologous {alpha}-amino acids in aqueous sodium fluoride solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, K., E-mail: krpal25@yahoo.co [Department of Physics, Government College of Engg., Tirunelveli 627 007, Tamilnadu (India); Edwin Gladson, S., E-mail: aseg_win@rediffmail.co [Department of Physics, St. Xavier' s Catholic College of Engg., Chunkankadai 629 003, Tamilnadu (India)

    2011-06-15

    Research highlights: Partial molar volume indicates strong solute-cosolute interaction in the NaF solution. Partial molar compressibility results compliment partial molar volume results. Hydration number proves that sodium fluoride has dehydration effect on amino acids. Interactions between sodium fluoride and (NH{sub 3}{sup +},COO{sup -}) group of amino acid are stronger. - Abstract: Density and ultrasonic speed of four amino acids (glycine, L-alanine, L-valine, and L-leucine) in aqueous sodium fluoride solutions {l_brace}(0.1 to 0.5) M{r_brace} have been measured at T = (308.15, 313.15, and 318.15) K. Apparent molar volumes (V{sub {phi}}), partial molar volumes (V{sub {phi}}{sup 0}), transfer volumes ({Delta}V{sub {phi}}{sup 0}) and hydration number (n{sub H}) are evaluated using density data. Adiabatic compressibility ({beta}{sub s}), change ({Delta}{beta}{sub s}), and relative change in compressibility ({Delta}{beta}{sub s}/{beta}{sub 0}), apparent molar compressibility (K{sub {phi}}), partial molar compressibility (K{sub {phi}}{sup 0}), transfer compressibility ({Delta}K{sub {phi}}{sup 0}), and hydration number (n{sub H}) have been calculated using ultrasonic speed data. The linear correlation of V{sub {phi}}{sup 0},{Delta}V{sub {phi}}{sup 0},K{sub {phi}}{sup 0} and {Delta}K{sub {phi}}{sup 0} for a homologous series of amino acids have been used utilised to calculate the contribution of charged end groups (NH{sub 3}{sup +}, COO{sup -}), CH{sub 2} group and other alkyl chain of the amino acids. The analysis shows that the ion-ion interactions are much stronger than ion-hydrophobic interactions over the entire concentration range of sodium fluoride. It is observed that sodium fluoride has a strong dehydration effect on amino acids.

  10. Comparing Eruption Space of the Lower Third Molar in Unerupted and Erupted Teeth via Digital Anoramic Radiography in Patients Referring to Yazd Dental College during 2011-13

    Directory of Open Access Journals (Sweden)

    F Ezoddini Ardakani

    2014-08-01

    Conclusion: Increasing the angle between second and third molar as well as inadequate space of retro-molar can lead to impaction of lower third molar, but the width of third molar and the Gonial angle size did not reveal any significant role in determination of impaction or eruption of third molar.

  11. Hydrogen bonding interactions between ethylene glycol and water:density,excess molar volume,and spectral study

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Studies of the density and the excess molar volume of ethylene glycol (EG)-water mixtures were carried out to illustrate the hydrogen bonding interactions of EG with water at different temperatures. The re-sults suggest that a likely complex of 3 ethylene glycol molecules bonding with 4 water molecules in an ethylene glycol-water mixture (EGW) is formed at the maximal excess molar volume,which displays stronger absorption capabilities for SO2 when the concentration of SO2 reaches 400×10?6 (volume ratio) in the gas phase. Meanwhile,FTIR and UV spectra of EGWs were recorded at various EG concentra-tions to display the hydrogen bonding interactions of EG with water. The FTIR spectra show that the stretching vibrational band of hydroxyl in the EGWs shifts to a lower frequency and the bending vibra-tional band of water shifts to a higher frequency with increasing the EG concentration,respectively. Furthermore,the UV spectra show that the electron transferring band of the hydroxyl oxygen in EG shows red shift with increasing the EG concentration. The frequency shifts in FTIR spectra and the shifts of absorption bands in UV absorption spectra of EGWs are interpreted as the strong hydrogen bonding interactions of the hydrogen atoms in water with the hydroxyl oxygen atoms of EG.

  12. Effect of molarity of TiO2 seeded-template to the growth of ZnO nanostructures

    Science.gov (United States)

    Asib, N. A. M.; Afaah, A. N.; Aadila, A.; Mahmud, M. R.; Lim, Y. C.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.; Khusaimi, Z.

    2015-05-01

    ZnO nanostructures were deposited by solution-immersion method on TiO2 layers by sol-gel spin-coating technique. Seven layers of TiO2 were coated on glass substrates at different molarities, followed by annealing treatment and solution-immersion process in aqueous solution containing 1:1 ratio of 0.05 M of zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and hexamethylenetetramine (HMTA) (C6H12N4). FESEM images confirmed that ZnO nanostructures grown on TiO2 seeded-template are in needle-like shape with smaller tip can be observed. Photoluminescence (PL) spectroscopy showed that as the molarity of TiO2 seeded- template increase, the intensity of PL emission at UV region decrease. UV emission peak for 0.10 M and 0.25 M are higher compared to UV emission peak film of 0.50 M and 1.00 M, which are too low. Meanwhile, the UV absorption properties of the nanostructured thin film for 0.25 M of TiO2 seeded-template was higher compared to other thin films.

  13. A study on the environmental conditions of the microsparite (Molar-tooth) carbonates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Along with the progress in research on the Precambrian, Molar-tooth carbonates (simplified as MT, or microsparite carbonates or MT structure) which were formed in the Middle-Late Proterozoic have become a hot subject recently. The Proterozoic Molar-tooth (MT) carbonate rocks refer to those Meso- to Neoproterozoic (1600-650 Ma) carbonates with MT structure, i.e., a series of peculiar, ptygmatically folded and spar-filled cracks in fine-grained carbonates of Precambrian age, located in the environment of mid- to inner ramp and shallow platform. MTS, like a bridge connecting the inorganic world with the organic one, are closely related to the evolution of paleo-oceans, atmosphere and biosphere. Their development and/or recession are/is related to the origin of life and the abruption of sedimentary geochemistry events of marine carbonates. By using modern instruments and testing methods adequately, the contents of oxides in sandstones were measured and the REE distribution pattern curves were established; an accurate value of isotopic ratio of 87Sr/86Sr was obtained, that is, the age of MT formation is about 750-900 Ma; C and O isotopes of some fresh micrite limestone samples were analyzed; the energy spectrum analysis revealed that the MT consists mainly of microspar calcite, while as for its chemical composition, the matrix shows outstanding peaks of Ca, Mg, Al, Si, and K. The geochemical indicators proved that Neoproterozoic MT carbonates in the Jilin-Liaoning region were developed at the margin of a stable continent, in the torrid zone where the paleo-temperature was about 50℃, the seawater had normal salinity when MT was formed during the Wanlong period in southern Jilin and during the Yingchengzi and Xingmincun periods in eastern Liaoning. The sedimentary environment was located in the inner ramp. In summary, it is of great importance to understand the origin of MT, ascertain the paleo-climate and paleo-environment characteristics, constrain the age and the

  14. MEASURED DENSITIES, REFRACTIVE INDICES, EXCESS MOLAR VOLUMES AND DEVIATIONS CALCULATED FROM MOLAR REFRACTION OF THE BINARY MIXTURE OF ETHANOL + 1-NONANOL AND TERNARY MIXTURE ETHANOL + 1-NONANOL + WATER AT 293.15 K

    Directory of Open Access Journals (Sweden)

    Mehmet MAHRAMANLIOĞLU

    2000-03-01

    Full Text Available Densities, and refractive indices were measured for the binary system ethanol + 1-nonanol and ternary system ethanol + 1-nonanol + water at 293.15 K. The excess molar volumes, and the deviations molar refraction were calculated for binary and ternary system. Redlich-Kister type equation was fitted to the excess molar volumes and, the deviations from a mole fraction average of the molar refraction, and the values of coefficients were calculated

  15. Trace element profiles in modern horse molar enamel as tracers of seasonality: Evidence from micro-XRF, LA-ICP-MS and stable isotope analysis

    Science.gov (United States)

    de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe

    2016-04-01

    A combination of laboratory micro-X-ray Fluorescence (μXRF) and stable carbon and oxygen isotope analysis shows that trace element profiles from modern horse molars reveal a seasonal pattern that co-varies with seasonality in the oxygen isotope records of enamel carbonate from the same teeth. A combination of six cheek teeth (premolars and molars) from the same individual yields a seasonal isotope and trace element record of approximately three years recorded during the growth of the molars. This record shows that reproducible measurements of various trace element ratios (e.g., Sr/Ca, Zn/Ca, Fe/Ca, K/Ca and S/Ca) lag the seasonal pattern in oxygen isotope records by 2-3 months. Laser Ablation-ICP-Mass Spectrometry (LA-ICP-MS) analysis on a cross-section of the first molar of the same individual is compared to the bench-top tube-excitation μXRF results to test the robustness of the measurements and to compare both methods. Furthermore, trace element (e.g. Sr, Zn, Mg & Ba) profiles perpendicular to the growth direction of the same tooth, as well as profiles parallel to the growth direction are measured with LA-ICP-MS and μXRF to study the internal distribution of trace element ratios in two dimensions. Results of this extensive complementary line-scanning procedure shows the robustness of state of the art laboratory micro-XRF scanning for the measurement of trace elements in bioapatite. The comparison highlights the advantages and disadvantages of both methods for trace element analysis and illustrates their complementarity. Results of internal variation within the teeth shed light on the origins of trace elements in mammal teeth and their potential use for paleo-environmental reconstruction.

  16. The rectilinear Steiner ratio

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    PO de Wet

    2005-06-01

    Full Text Available The rectilinear Steiner ratio was shown to be 3/2 by Hwang [Hwang FK, 1976, On Steiner minimal trees with rectilinear distance, SIAM Journal on Applied Mathematics, 30, pp. 104– 114.]. We use continuity and introduce restricted point sets to obtain an alternative, short and self-contained proof of this result.

  17. Gender Ratio in Dyslexia.

    Science.gov (United States)

    Miles, T. R.; Haslum, M. N.; Wheeler, T. J.

    1998-01-01

    A study involving 11,804 British children (age 10) found that when specified criteria for dyslexia were used, 269 children qualified as dyslexic. These included 223 boys and 46 girls, for a ratio of 4.51 to 1. Difficulties in interpreting these data are discussed and a defense of the criteria is provided. (Author/CR)

  18. Development of the first permanent mandibular molar in young children with unilateral complete cleft lip and palate (UCCLP)

    DEFF Research Database (Denmark)

    Hermann, Nuno Vibe; Darvann, Tron A; Kreiborg, Sven

    Development of the first permanent mandibular molar in young children with unilateral complete cleft lip and palate (UCCLP)......Development of the first permanent mandibular molar in young children with unilateral complete cleft lip and palate (UCCLP)...

  19. Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments

    Directory of Open Access Journals (Sweden)

    Maryam Poosti

    2013-01-01

    Full Text Available Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction

  20. Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments

    Directory of Open Access Journals (Sweden)

    Maryam Poosti

    2012-09-01

    Full Text Available Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction.

  1. Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

    Science.gov (United States)

    Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

    2015-01-01

    SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698

  2. Radiographic findings on 3rd molars removed in 20-year-old men.

    Science.gov (United States)

    Rajasuo, Ari; Peltola, Jaakko; Ventä, Irja; Murtomaa, Heikki

    2003-10-01

    In this study we assess radiographic findings characteristic of mandibular 3rd molars that had required either routine or surgical extraction. X-ray findings relating to acute pericoronitis were also examined. The material was collected by investigating patient records and rotational panoramic radiographs of 20-year-old Finnish male conscripts (n = 738) treated during military service because of 3rd-molar-related problems. The follicle around the crown of mandibular 3rd molars with acute pericoronitis was enlarged in 19% of cases and in 13% of chronic symptom-free pericoronitis cases (not statistically significant difference). Mandibular 3rd molars extracted surgically were more often mesially inclined than those extracted routinely (61% vs. 23%; P pericoronitis [around 27% vs. 39% of the teeth routinely extracted (OR 0.5, 95% CI 0.3-0.8)]. In 86% of cases the space between 2nd molar and ramus of the mandible was narrower than the 3rd molar extracted surgically, whereas this was 62% in routine extraction cases (P < 0.001). We conclude that there are some typical 3rd-molar findings in rotational panoramic radiographs that show a need for surgical extraction.

  3. Review of flap design influence on the health of the periodontium after mandibular third molar surgery.

    Science.gov (United States)

    Karaca, Inci; Simşek, Sebnem; Uğar, Dilek; Bozkaya, Süleyman

    2007-07-01

    The purpose of this study is to review the effect of flap design in terms of periodontal status of the preceding second molar after lower third molar surgery. Impacted lower third molar surgery may result in periodontal complications on the distal surface of the adjacent second molar. Flap design that is used during impacted third molar surgery is important to prevent those complications. Several different flap techniques, mainly envelope, triangular (vertical) flaps, and their modifications have been developed to minimize those complications. Each technique has some advantages as well as disadvantages. It is also reported that the selection of a flap design does not seem to have a lasting effect on the health of periodontal tissue. The effect of the type of flap used for lower third molar surgery on the periodontal status of the second molar, as well as the factors that may influence this outcome, has been uncertain. The decision to use on one or the other of the flaps should be based on surgeon's preference.

  4. Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Mi Ree; Moon, Young Mi; Seo, Min Seock [Dept. of Conservative Dentistry, Wonkang University Daejeon Dental Hospital, Daejeon (Korea, Republic of)

    2015-12-15

    This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

  5. Restorasi Resin Komposit Menggunakan Pasak Tapered Self Threading Pada Molar Ketiga Kiri Mandibula

    Directory of Open Access Journals (Sweden)

    Ellen Krisanti

    2013-06-01

    Composite Resin Restoration Using Tapered Self Threading Poston Left Mandibular Third Molar. Root canal morphology of mandibular third molar has more complex variation than the other molars. In third molar, the extraction teeth are often executed; however, the third molar can be maintained in other conditions. One visit root canal treatment is a therapy option for this case. The purpose of this case report is to show the success of one visit root canal treatment in third molar with pulp necrosis by restoring the composite resin through tapered self-treading post. A 20 year-old female patient who came to the Prof Soedomo RSGM, FKG UGM complained about the pain when chewing food on her third molar and positive in percussion. The radiographs showed that there was an incomplete restoration. There was a gap between cavities with restoration. The treatment plan for this case was one visit root canal treatment and composite resin with tapered self-threading post as final restoration. From the case, it can concluded that one visit root canal treatment results in a smaller chance for microorganism recontamination than the multi-visit in order to ensure the success of the treatment. Direct composite resin restoration with tapered self-threading dowel is an alternative restoration after endodontic treatment because it works out faster and more retentive.

  6. Predicting lower third molar eruption on panoramic radiographs after cephalometric comparison of profile and panoramic radiographs.

    Science.gov (United States)

    Begtrup, Anders; Grønastøð, Halldis Á; Christensen, Ib Jarle; Kjær, Inger

    2013-08-01

    Previous studies have suggested methods for predicting third molar tooth eruption radiographically. Still, this prediction is associated with uncertainty. The aim of the present study was to elucidate the association between cephalometric measurements on profile and panoramic radiographs and to find a simple and reliable method for predicting the eruption of the mandibular third molar by measurements on panoramic radiographs. The material consisted of profile and panoramic radiographs, taken before orthodontic treatment, of 30 males and 23 females (median age 22, range 18-48 years), with no known diseases. Cephalometric measurements on panoramic and profile radiographs were performed and compared, i.e. the size of the gonial angle and sagittal distance from the alveolar margin between the mandibular central incisors to the anterior border of the mandibular ramus. Furthermore, the mesiodistal width of the second molar was measured. Statistical methods included analysis of method error. The probability of eruption was modelled using logistic regression analysis. Correlation was observed between all measurements on profile and panoramic radiographs. The skeletal variable expressing the length from the ramus to the incisors (olr-id) showed a statistically significant correlation. By combining this length with the mesiodistal width of the lower second molar, the prediction of eruption of the lower third molar was strengthened. A new formula for calculating the probability of eruption of the mandibular third molar was made and a graph constructed for easy assessment. In conclusion, a simple method for predicting the eruption of the third molar is presented.

  7. Radiographic correlation of dental and skeletal age: Third molar, an age indicator

    Directory of Open Access Journals (Sweden)

    G N Suma

    2011-01-01

    Full Text Available Background: Age estimation plays a great role in forensic investigations, orthodontic and surgical treatment planning, and tooth transplantation. Teeth offer an excellent material for age determination by stages of development below the age of 25 years and by secondary changes after the age of 25 years. Third molar is often not included for this purpose due to its notorious developmental patterns. The aim of this study was to evaluate the development of third molar anlage in relation to skeletal maturities and the chronological age. Materials and Methods: One hundred and fifty-six young individuals, 78 males and 78 females, were selected. The stages of development of all the third molars in every individual were determined from panoramic radiographs. The skeletal development was assessed using hand wrist radiographs. Data were analyzed statistically for mean value, standard deviation and the relationship between the recorded characteristics. Results: A strong correlation was found between third molar development and skeletal maturity (in males: r=0.88, P<0.001; in females: r=0.77 for maxillary third molar and 0.89 for mandibular third molar, P<0.001. Conclusion: Hence, it is concluded that a strong correlation exists between chronological age, developmental stages of third molars and maturation of epiphyses of hand. Any of the three parameters could be used for the assessment of other maturities.

  8. Sex determination in modern Greeks using diagonal measurements of molar teeth.

    Science.gov (United States)

    Zorba, Eleni; Moraitis, Konstantinos; Eliopoulos, Constantine; Spiliopoulou, Chara

    2012-04-10

    Sex determination is a necessary step in the investigation of unidentified human remains from a forensic context. Teeth, as one of the strongest tissues in the human body, can be used for this purpose. Most studies of sexual dimorphism in teeth are based on the traditional mesiodistal and buccolingual crown measurements. The purpose of this study is to examine the degree of sexual dimorphism in permanent molars of modern Greeks using crown and cervical diagonal diameters, and to evaluate their applicability in sex determination. A total of 344 permanent molars in 107 individuals (53 male and 54 female) from the Athens Collection were examined. Crown and cervical diagonal diameters of both maxillary and mandibular molars were measured. It was found that males have larger molars than females and in 19 out of 24 dimensions measured male molars exceeded female molars significantly (Pdiagonal diameters have found to be more sexually diamorphic than crown diagonal diameters. In discriminant function analysis the variables entered more frequently were the cervical diagonal diameters mainly of mandibular molars. Classification accuracy was found to be 93% for the total sample, 77.4% for upper jaw, and 88.4% for the lower jaw. Accuracy rates were higher for cervical than crown diagonal diameters. The data generated from the present study suggest that this metric method can be useful and reliable for sex determination, especially when the traditional dental measurements are not applicable.

  9. Pulpal responses to cavity preparation in aged rat molars.

    Science.gov (United States)

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

    2006-10-01

    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.

  10. Correlated Nitrogen and Carbon Anomalies in an Anhydrous Interplanetary Dust Particle - Implications for Extraterrestrial Organic Matter Accreted by the Prebiotic Earth

    Energy Technology Data Exchange (ETDEWEB)

    Floss, C; Stadermann, F J; Bradley, J P; Dai, Z; Bajt, S; Graham, G

    2003-12-17

    Given the ubiquitous presence of H and N isotopic anomalies in interplanetary dust particles (IDPs) and their probable association with carbonaceous material, the lack of similar isotopic anomalies in C has been a major conundrum. We report here the first observation of correlated N and C isotopic anomalies in organic matter within an anhydrous IDP. The {sup 15}N composition of the anomalous region is the highest seen to date in an IDP and is accompanied by a moderate depletion in {sup 13}C. Our observations establish the presence of hetero-atomic organic compounds of presolar origin among the constant flux of carbonaceous material accreting to the terrestrial planets within IDPs. Theoretical models suggest that low temperature formation of organic compounds in cold interstellar molecular clouds does produce C and N fractionations, but it remains to be seen if these models can reproduce the specific effects we observe here.

  11. Thermal evaporation-induced anhydrous synthesis of Fe3O4-graphene composite with enhanced rate performance and cyclic stability for lithium ion batteries.

    Science.gov (United States)

    Dong, Yucheng; Ma, Ruguang; Hu, Mingjun; Cheng, Hua; Yang, Qingdan; Li, Yang Yang; Zapien, Juan Antonio

    2013-05-21

    We present a high-yield and low cost thermal evaporation-induced anhydrous strategy to prepare hybrid materials of Fe3O4 nanoparticles and graphene as an advanced anode for high-performance lithium ion batteries. The ~10-20 nm Fe3O4 nanoparticles are densely anchored on conducting graphene sheets and act as spacers to keep the adjacent sheets separated. The Fe3O4-graphene composite displays a superior battery performance with high retained capacity of 868 mA h g(-1) up to 100 cycles at a current density of 200 mA g(-1), and 539 mA h g(-1) up to 200 cycles when cycling at 1000 mA g(-1), high Coulombic efficiency (above 99% after 200 cycles), good rate capability, and excellent cyclic stability. The simple approach offers a promising route to prepare anode materials for practical fabrication of lithium ion batteries.

  12. Brucine salts of L-alpha-hydroxy acids: brucinium hydrogen (S)-malate pentahydrate and anhydrous brucinium hydrogen (2R,3R)-tartrate at 130 K.

    Science.gov (United States)

    Smith, Graham; Wermuth, Urs D; White, Jonathan M

    2006-06-01

    The structures of two brucinium (2,3-dimethoxy-10-oxostrychnidinium) salts of the alpha-hydroxy acids L-malic acid and L-tartaric acid, namely brucinium hydrogen (S)-malate pentahydrate, C23H27N2O4+.C4H5O5-.5H2O, (I), and anhydrous brucinium hydrogen (2R,3R)-tartrate, C23H27N2O4+.C4H5O6-,(II), have been determined at 130 K. Compound (I) has two brucinium cations, two hydrogen malate anions and ten water molecules of solvation in the asymmetric unit, and forms an extensively hydrogen-bonded three-dimensional framework structure. In compound (II), the brucinium cations form the common undulating brucine sheet substructures, which accommodate parallel chains of head-to-tail hydrogen-bonded tartrate anion species in the interstitial cavities.

  13. Effects of ionizing radiation on wound healing of alveolar bone socket after extraction of rat maxillary molars

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Hiroshi; Yosue, Takashi [Nippon Dental Univ., Tokyo (Japan). School of Dentistry; Nasu, Masanori

    2001-05-01

    The purpose of this study was to examine the effects of radiation on the healing process of tooth extraction wounds. X-ray doses of 10 Gy or 20 Gy were delivered, once, to the maxillofacial area of Wistar-strain rats. Then, 24 hours after irradiation, the maxillary first molars were extracted bilaterally. The animals were sacrificed 3, 7, 10, 14, 21, 42, and 84 days after tooth extraction, and the maxilla were sliced, to make thin sections. These specimens were then double stained with alkaline phosphatase (ALP) and tartrate resistant acid phosphatase (TRAP). The ratio of bone area to socket area (bone formation ratio), the ratio of bone length to ALP positive area length (ALP positive ratio), and the number of TRAP-positive cells, were evaluated. The results showed: The bone formation ratios at days 3 and 7 after tooth extraction were significantly low in both irradiation groups, compared with those for the non-irradiation group. The ALP positive reaction ratio peaked 7 days after in the non-irradiation group. In both irradiation groups, the ratios that were worked out at 3 days and 7 days after were significantly lower than those in the non-irradiation group. There was no significant difference in the number of TRAP-positive cells between the non-irradiation group and the 10 Gy irradiation group. In the 20 Gy irradiation group, the TRAP-positive cell count plummeted to a significantly low level at 3 days after tooth extraction, compared with that in the non-irradiation group. (author)

  14. Effect of age, impaction types and operative time on inflammatory tissue reactions following lower third molar surgery

    OpenAIRE

    Obi Emeka V; Bamgbose Babatunde O; Adeyemo Wasiu L; Bello Seidu A; Adeyinka Ademola A

    2011-01-01

    Abstract Background Postoperative mobidity following third molar surgery is affected by a number of factors. The study of these factors is essential for effective planning and limitation of morbidity. The aim of this study was to determine the effect of age, type of impaction and operative time on immediate postoperative tissue reactions following mandibular third molar surgery. Methods Consecutive patients with impacted mandibular third molar teeth were studied. All the third molars were cla...

  15. Significance of Radiological Variables Studied on Orthopantamogram to Pridict Post-Operative Inferior Alveoler Nerve Paresthesia After Third Molar Extraction

    OpenAIRE

    Pathak, Sachin; Mishra, Nitin; Rastogi, Madhur Kant; Sharma, Shalini

    2014-01-01

    Context: Removal of impacted third molar is a procedure that is often associated with post-operative complications. The rate of complications is somewhat high because of its proximity to the vital structures. Inferior alveolar nerve paresthesia is one of the common complications of impacted their molar surgery. This is due to intimate relationship between roots of mandibular third molar and inferior alveolar canal. To access the proximity of inferior alveolar canal to third molar many diagnos...

  16. Coronectomy of deeply impacted lower third molar: incidence of outcomes and complications after one year follow-up

    OpenAIRE

    Jimoh Olubanwo Agbaje; Guido Heijsters; Ahmed Sobhy Salem; Sarah Van Slycke; Serge Schepers; Constantinus Politis; Luc Vrielinck

    2015-01-01

    ABSTRACT Objectives The purpose of present study was to assess the surgical management of impacted third molar with proximity to the inferior alveolar nerve and complications associated with coronectomy in a series of patients undergoing third molar surgery. Material and Methods The position of the mandibular canal in relation to the mandibular third molar region and mandibular foramen in the front part of the mandible (i.e., third molar in close proximity to the inferior alveolar nerve [IAN]...

  17. Impacted Mandibular Third Molars: Review of Literature and a Proposal of a Combined Clinical and Radiological Classification

    OpenAIRE

    2015-01-01

    Tooth impaction is a pathological situation where a tooth fails to attain its normal functional position. Impacted third molars are commonly encountered in routine dental practice. The impaction rate is higher for third molars when compared with other teeth. The mandibular third molar impaction is said to be due to the inadequate space between the distal of the second mandibular molar and the anterior border of the ascending ramus of the mandible. Impacted teeth may remain asymptomatic or may...

  18. Thermal properties and structural characterizations of new types of phase change material: Anhydrous and hydrated palmitic acid/camphene solid dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tu, E-mail: tulee@cc.ncu.edu.tw; Chiu, Yu Hsiu; Lee, Yun; Lee, Hung Lin

    2014-01-10

    Highlights: • Solid dispersion is implemented on phase change materials. • Water is added as a tertiary component. • Specific heat of solid is increased by partially amorphous camphene. • Microstructures are characterized by LTDSC, PXRD and SAXS. • Thermal properties are linked to microstructures. - Abstract: Two new types of phase change material anhydrous and hydrated palmitic acid/camphene solid dispersions (PA1CA1) are prepared and characterized by low-temperature differential scanning calorimetry, powder X-ray diffraction, small-angle X-ray scattering and temperature–history method. Their microstructures contain nanometer-sized palmitic acid (PA) crystallites with lamellar periodicity dispersed in a partially amorphous plastic crystalline camphene (CA) matrix. The PA phase apparently possesses a relatively high latent heat value inherited from the pristine crystalline PA of 229.7 ± 0.1 kJ kg{sup −1}. The relatively high specific heat of solid, C{sub ps}, for anhydrous PA1CA1 of 2.17 ± 0.06 kJ kg{sup −1} K{sup −1} is originated from the presence of disordered CA matrix. Hydration of PA1CA1 can further increase the C{sub ps} to 2.61 ± 0.01 kJ kg{sup −1} K{sup −1}. The mixing of partially amorphous CA, some PA and the small amount of water may have turned the matrix into more disorder due to their different bonding natures, molecular weights, and various molecular shapes and sizes.

  19. Initial tooth movement under extraoral force and considerations for controlled molar movement.

    Science.gov (United States)

    Yoshida, N; Jost-Brinkmann, P G; Yamada, Y

    1995-01-01

    Initial movement of the maxillary first molars under the application of straight-pull, cervical-pull, and high-pull headgear was measured in human subjects. Facebow deflection can influence molar movement as the relationship of the force vector to the molar's center of resistance changes with an increase of force. The present study proposes using headgear with a combination of variable-pull headcap and short outer bow. A variable-pull headcap allows a great range in force direction. The direction of the headgear force system can be accurately determined using a short outer bow.

  20. Low-tmperature Heat Capacities and Standard Molar Enthalpy of Formation of 4-Nitrobenzyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    MENG, Qingfen; TAN, Zhicheng; WANG, Xiaohuan; DONG, Yaping; LI, Wu; SHI, Quan

    2009-01-01

    Low-temperature heat capacities of 4-nitrobenzyl alcohol (4-NBA) have been measured by a high precision automated adiabatic calorimeter over the temperature range from 78 to 396 K. The melting temperature, the molar calculated in the range from 80 to 400 K at the interval of 5 K. The constant-volume energy and standard molar en- at T=298.15 K. The standard molar enthalpy of formation has been derived, ΔfHom(C7H7NO3, s)=-(206.49± namic quantities through a Hess thermochemical cycle.