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Sample records for high severity crown

  1. Fracture strength of monolithic all-ceramic crowns made of high translucent yttrium oxide-stabilized zirconium dioxide compared to porcelain-veneered crowns and lithium disilicate crowns.

    Science.gov (United States)

    Johansson, Camilla; Kmet, Gratiela; Rivera, Johnny; Larsson, Christel; Vult Von Steyern, Per

    2014-02-01

    The aim of the study was to provide data on the fracture strength of monolithic high translucent Y-TZP crowns and porcelain-veneered high translucent Y-TZP crown cores and to compare that data with the fracture strength of porcelain-veneered Y-TZP crown cores and monolithic lithium disilicate glass-ceramic crowns. Sixty standardized crowns divided into six groups (n = 10) were fabricated: monolithic high translucent Y-TZP crowns, brand A, monolithic high translucent Y-TZP crowns, brand B, veneered high translucent Y-TZP crown cores, brand A, veneered high translucent Y-TZP crown cores, brand B, heat-pressed monolithic lithium disilicate crowns and veneered Y-TZP crown cores. All crowns were thermocycled, cemented onto dies, cyclically pre-loaded and finally loaded to fracture. The monolithic Y-TZP groups showed significantly higher fracture strength (2795 N and 3038 N) compared to all other groups. The fracture strength in the veneered Y-TZP group (2229 N) was significantly higher than the monolithic lithium disilicate group (1856 N) and the veneered high translucent Y-TZP groups (1480 N and 1808 N). The fracture strength of monolithic high translucent Y-TZP crowns is considerably higher than that of porcelain-veneered Y-TZP crown cores, porcelain-veneered high translucent Y-TZP crown cores and monolithic lithium disilicate crowns. The fracture strength of a crown made of monolithic high translucent Y-TZP is, with a large safety margin, sufficient for clinical use for the majority of patients. Porcelain-veneered Y-TZP crown cores show higher fracture resistance than monolithic lithium disilicate crowns.

  2. Composite crown-form crowns for severely decayed primary molars: a technique for restoring function and esthetics.

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    Ram, D; Peretz, B

    2000-01-01

    Current developments in esthetic dentistry center around new techniques and materials that improve the ability of the clinician to provide esthetic services. This article describes a step-by-step method of placing composite crown-form crowns on severely decayed primary mandibular molars. The described technique allows for restoring, as close as possible, form and function lost to caries in an esthetic mode in cases of severely decayed primary molars that would have required stainless steel crowns had they been treated traditionally. Disadvantages of this treatment mode are that dryness may not be prevented in the proximal margins, especially where subgingival carious involvement is encountered and the margin areas may be contaminated with gingival fluid or blood. Although no long-term follow-up has been reported for the technique, when strong opposition by the parent or child to the stainless steel crown is encountered, and a desire for esthetic restoration is strongly expressed, the composite crown-form crowns may be considered as an alternative.

  3. Fire severity and ecosytem responses following crown fires in California shrublands.

    Science.gov (United States)

    Keeley, Jon E; Brennan, Teresa; Pfaff, Anne H

    2008-09-01

    Chaparral shrublands burn in large high-intensity crown fires. Managers interested in how these wildfires affect ecosystem processes generally rely on surrogate measures of fire intensity known as fire severity metrics. In shrublands burned in the autumn of 2003, a study of 250 sites investigated factors determining fire severity and ecosystem responses. Using structural equation modeling we show that stand age, prefire shrub density, and the shortest interval of the prior fire history had significant direct effects on fire severity, explaining > 50% of the variation in severity. Fire severity per se is of interest to resource managers primarily because it is presumed to be an indicator of important ecosystem processes such as vegetative regeneration, community recovery, and erosion. Fire severity contributed relatively little to explaining patterns of regeneration after fire. Two generalizations can be drawn: fire severity effects are mostly shortlived, i.e., by the second year they are greatly diminished, and fire severity may have opposite effects on different functional types. Species richness exhibited a negative relationship to fire severity in the first year, but fire severity impacts were substantially less in the second postfire year and varied by functional type. Much of this relationship was due to alien plants that are sensitive to high fire severity; at all scales from 1 to 1000 m2, the percentage of alien species in the postfire flora declined with increased fire severity. Other aspects of disturbance history are also important determinants of alien cover and richness as both increased with the number of times the site had burned and decreased with time since last fire. A substantial number of studies have shown that remote-sensing indices are correlated with field measurements of fire severity. Across our sites, absolute differenced normalized burn ratio (dNBR) was strongly correlated with field measures of fire severity and with fire history at a

  4. Fire severity and ecosytem responses following crown fires in California shrublands

    Science.gov (United States)

    Keeley, J.E.; Brennan, T.; Pfaff, A.H.

    2008-01-01

    Chaparral shrublands burn in large high-intensity crown fires. Managers interested in how these wildfires affect ecosystem processes generally rely on surrogate measures of fire intensity known as fire severity metrics. In shrublands burned in the autumn of 2003, a study of 250 sites investigated factors determining fire severity and ecosystem responses.Using structural equation modeling we show that stand age, prefire shrub density, and the shortest interval of the prior fire history had significant direct effects on fire severity, explaining >50% of the variation in severity.Fire severity per se is of interest to resource managers primarily because it is presumed to be an indicator of important ecosystem processes such as vegetative regeneration, community recovery, and erosion. Fire severity contributed relatively little to explaining patterns of regeneration after fire. Two generalizations can be drawn: fire severity effects are mostly short-lived, i.e., by the second year they are greatly diminished, and fire severity may have opposite effects on different functional types.Species richness exhibited a negative relationship to fire severity in the first year, but fire severity impacts were substantially less in the second postfire year and varied by functional type. Much of this relationship was due to alien plants that are sensitive to high fire severity; at all scales from 1 to 1000 m2, the percentage of alien species in the postfire flora declined with increased fire severity. Other aspects of disturbance history are also important determinants of alien cover and richness as both increased with the number of times the site had burned and decreased with time since last fire.A substantial number of studies have shown that remote-sensing indices are correlated with field measurements of fire severity. Across our sites, absolute differenced normalized burn ratio (dNBR) was strongly correlated with field measures of fire severity and with fire history at a site

  5. Tree crown delineation from high resolution airborne LiDAR based on densities of high points

    NARCIS (Netherlands)

    Rahman, M.Z.A.; Gorte, B.G.H.

    2009-01-01

    Tree detection and tree crown delineation from Airborne LiDAR has been focusing mostly on utilizing the canopy height model (CHM). This paper presents a method for individual tree crown delineation based on densities of high points (DHP) from the high resolution Airborne LiDAR. The DHP method relies

  6. In vitro fracture behavior of maxillary premolars with metal crowns and several post-and-core systems.

    NARCIS (Netherlands)

    Fokkinga, W.A.; Kreulen, C.M.; Bell-Ronnlof, A.M. Le; Lassila, L.V.; Vallittu, P.K.; Creugers, N.H.J.

    2006-01-01

    The in vitro fracture behavior of severely damaged premolars, restored with metal crowns with limited ferrule and several post-and-core systems, was investigated. Crowns of maxillary premolars were removed and canals were prepared with Gates Glidden drills and with Parapost drills. Groups of 11

  7. Successful Restoration of Severely Mutilated Primary Incisors Using a Novel Method to Retain Zirconia Crowns - Two Year Results.

    Science.gov (United States)

    El Shahawy, Osama Ibrahim; O'Connell, Anne C

    This manuscript describes a simple reliable technique for restoring severely mutilated primary anterior teeth. A rigid glass ionomer post is created over which zirconia crowns can be fitted to achieve a long-term stable esthetic restoration for primary anterior teeth. Children aged 2-5 years with two up to six extensively decayed upper primary incisors were included. Fuji IX was condensed into an intracanal space created to a depth of 3mm, to provide a core which also extended 3mm supragingivally. Crown preparations were completed upon these cores. Zirconia crowns (Nusmile, Houston Texas USA) were fitted and cemented over the prepared cores. All patients were recalled at regular intervals. Twenty-three healthy children with 86 restorations participated in the study. The overall survival of the restorations was 95.3% after 12 months and 80.2% after 24 months. According to Kaplan-Meier survival analysis, the median survival time was not reached while the estimated mean survival time was 22.9 months. This newly described clinical technique is simple and reliable to use for restoration of extensively decayed primary incisors. Use of zirconia crowns retained using this technique offers superior esthetic, durable restorations with remarkable gingival response up to 24 months.

  8. The Use of Telescopic Crowns in Removable Partial Denture Treatment for Patients with Severe Periodontal Disease: Two Patient Case History Reports.

    Science.gov (United States)

    Cho, Jin-Hyun; Cho, Sung-Am

    2016-01-01

    Two patient case histories are described as examples of treatment of severe periodontitis in severely compromised partial dentitions. Management consisted of periodontal treatment and telescopic crown support for removable partial dentures with friction pin retention.

  9. Glass Ceramic CAD/CAM crowns and severely altered posterior teeth: a three levels study.

    Science.gov (United States)

    Fages, Michel; Corn, Stephane; Slangen, Pierre; Raynal, Jacques; Ienny, Patrick; Turzo, Kinga; Cuisinier, Frederic; Durand, Jean-Cédric

    2017-08-19

    For many practitioners, longevity of full glass ceramic crowns in the posterior area, molars and premolars, remains a real challenge. The purpose of this article is to identify and evaluate the parameters that can significantly influence their resistance when preparing a tooth. The analysis proposed in this article relies on interrelated studies conducted at three levels: in vitro (mechanical tests), in silico (finite elements simulations) and in vivo (clinical survival rates). The in vitro and the in silico studies proved that an appropriate variation of the geometric design of the preparations enables to increase up to 80% the mechanical strength of ceramic reconstructions. The in vivo clinical study of CAD/CAM full ceramic crowns was performed in accordance with the principles stated within the in vitro and the in silico studies and provided a 98.97% success rate over a 6 years period. The variations of geometric design parameters for dental preparation allows for reconstructions with a mechanical breaking up to 80% higher than that of a non-appropriate combination. These results are confirmed in clinical practice.

  10. Honouring His Royal Highness the Crown Prince of Bhutan: Megalestes gyalsey (Odonata: Synlestidae).

    Science.gov (United States)

    Gyeltshen, T; Kalkman, V J; Orr, A G

    2017-03-22

    Megalestes gyalsey spec. nov. is described from a single male from Trongsa District in Bhutan. The species was discovered during field work conducted in 2015 for the Bhutan invertebrate biodiversity project. The species is named in honour of His Royal Highness Crown Prince Jigme Namgyel Wangchuck, the Gyalsey of Bhutan, on the occasion of his first birthday.

  11. Cs selective extraction from high level liquid wastes with crown calixarenes: Where are we today?

    Energy Technology Data Exchange (ETDEWEB)

    Simon, N.; Tournois, B.; Eymard, S.; Volle, G.; Rivalier, P.; Leybros, J.; Lanoe, J.Y.; Reynier-Tronche, N.; Ferlay, G.; Dozol, J.F

    2004-07-01

    This paper deals with the developments carried out around the caesium process these last years to prove its scientific feasibility, then to acquire technical feasibility.The crown-calixarenes molecules showed their efficiency towards selective Cs extraction and their superiority with respect to the traditional alkaline cations extraction systems: crown-ether molecules. After acquisition of experimental data, calculations of flow-sheet were carried out. Tests, first on simulated effluents, then on real effluents, demonstrated the scientific feasibility of the concept. The technical feasibility is currently in progress through the following studies: - hydrodynamic and transfer studies; - kinetics data are in progress; - calixarene molecule are known to be highly resistant molecules towards hydrolysis and radiolysis phenomena but regeneration studies have to be taken into account to define the industrial process. (authors)

  12. A Severe Outbreak of Crown and Root rot of Tomato Caused by Fusarium oxysporum f. sp. radicis-lycopersici in Malta

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    A. Porta-Puglia

    2005-12-01

    Full Text Available A severe outbreak of crown and root rot of tomato was observed in greenhouses in Malta in eight locations during the period November 2004 – February 2005. Besides root and crown symptoms, several plants showed cankers at the basal part of the stem. Fusarium oxysporum was constantly isolated from these plants. One isolate from each location was tested for pathogenicity on tomato seedlings. All these isolates caused severe necrotic lesions of the crown and roots, and stem cankers. It was concluded that F. oxysporum f. sp. radicis-lycopersici (FORL was the cause of the outbreak. Incidence ranged from 10 to 50%. Cold weather conditions occurring in Malta during the late fall and winter of 2004–2005 probably favoured the disease. The use of tomato cultivars or hybrids resistant to FORL is suggested for winter tomato crops in south Mediterranean areas.

  13. Dental crowns

    Science.gov (United States)

    ... still has its nerve, you may have some sensitivity to heat or cold. This should go away over time. Expect that it will take a few days to get used to the new crown in your mouth. Take care of your crown the same way you take care of your normal teeth. If you have a porcelain crown, you may ...

  14. Severidade da ferrugem-da-folha e seus efeitos sobre caracteres da panícula de aveia Crown rust severity and its effects on oat panicle characters

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    Renata Pereira da Cruz

    1999-04-01

    Full Text Available A ferrugem-da-folha (Puccinia coronata f.sp. avenae foi quantificada em quatro populações F3 de aveia (Avena sativa L. com o objetivo de estudar a severidade dessa moléstia e seus efeitos sobre seis caracteres da panícula. As populações utilizadas foram UFRGS 881920 x UFRGS 7, UFRGS 881920 x UFRGS 14, UFRGS 15 x UFRGS 7 e UFRGS 15 x UFRGS 14, sendo os genótipos UFRGS 881920 e UFRGS 15 resistentes à moléstia e os demais suscetíveis. A ferrugem-da-folha foi quantificada na época do florescimento, e próximo à maturação foram colhidas, em cada população, 10 plantas ao acaso por nota de ferrugem nas quais foram feitas as seguintes determinações: número de panículas, peso médio de panículas, número de grãos por planta e por panícula, peso de grãos e peso de mil grãos. A variabilidade em relação à severidade da ferrugem-da-folha foi analisada mediante a distribuição de freqüências das notas em cada população. A avaliação dos efeitos da moléstia sobre os caracteres da panícula foi feita pela análise de variância, análise de regressão polinomial e correlações fenotípicas. Os resultados obtidos demonstram haver ampla variação com respeito à severidade da moléstia nas populações estudadas, e os caracteres mais afetados foram o peso médio de panículas e o peso de mil grãos.Crown rust (Puccinia coronata f.sp. avenae was quantified in four F3 oat (Avena sativa L. populations with the objective of studying disease severity and its effects on six panicle characters. Populations used were UFRGS 881920 x UFRGS 7, UFRGS 881920 x UFRGS 14, UFRGS 15 x UFRGS 7 and UFRGS 15 x UFRGS 14, with genotypes UFRGS 881920 and UFRGS 15 being resistant and the others susceptible. Crown rust infection was quantified at flowering stage and near grain maturity 10 plants at random were harvested per crown rust score in each population, and the following determinations were made: number of panicles, mean panicle weight, number

  15. Development of a high-resolution melting marker for selecting Fusarium crown and root rot resistance in tomato.

    Science.gov (United States)

    Kim, Bichseam; Kim, Nahui; Kim, Jun Young; Kim, Byung Sup; Jung, Hee-Jeong; Hwang, Indoek; Noua, Ill-Sup; Sim, Sung-Chur; Park, Younghoon

    2016-03-01

    Fusarium crown and root rot is a severe fungal disease of tomato caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL). In this study, the genomic location of the FORL-resistance locus was determined using a set of molecular markers on chromosome 9 and an F2 population derived from FORL-resistant inbred 'AV107-4' (Solanum lycopersicum) × susceptible 'L3708' (Solanum pimpinellifolium). Bioassay performed using Korean FORL strain KACC 40031 showed single dominant inheritance of FORL resistance in the F2 population. In all, 13 polymerase chain reaction-based markers encompassing approximately 3.6-72.0 Mb of chromosome 9 were developed based on the Tomato-EXPEN 2000 map and SolCAP Tomato single nucleotide polymorphism array analysis. These markers were genotyped on 345 F2 plants, and the FORL-resistance locus was found to be present on a pericentromeric region of suppressed chromosomal recombination in chromosome 9. The location of the FORL-resistance locus was further confirmed by testing these markers against diverse commercial tomato and stock cultivars resistant to FORL. A restriction fragment length polymorphism marker, PNU-D4, located at approximately 6.1 Mb of chromosome 9 showed the highest match with the resistance locus and was used for conducting high-resolution melting analysis for marker-assisted selection of FORL resistance.

  16. Estimating average tree crown size using high-resolution airborne data

    Czech Academy of Sciences Publication Activity Database

    Brovkina, Olga; Latypov, I.; Cienciala, E.

    2015-01-01

    Roč. 9, may 13 (2015), 096053-1-096053-13 ISSN 1931-3195 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk OC09001 Institutional support: RVO:67179843 Keywords : crown size * airborne data * spruce * granulometry Subject RIV: GK - Forestry Impact factor: 0.937, year: 2015

  17. AN EVALUATION OF TWO GROUND-BASED CROWN CLOSURE ESTIMATION TECHNIQUES COMPARED TO CROWN CLOSURE ESTIMATES DERIVED FROM HIGH RESOLUTION IMAGERY

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    Two ground-based canopy closure estimation techniques, the Spherical Densitometer (SD) and the Vertical Tube (VT), were compared for the effect of deciduous understory on dominant/co-dominant crown closure estimates in even-aged loblolly (Pinus taeda) pine stands located in the N...

  18. Tensile bond strength of ceramic crowns to dentin using resin cements.

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    Simon, James F; de Rijk, Waldemar G; Hill, Jennifer; Hill, Nathaniel

    2011-01-01

    This study measured the bond strength of the self-adhesive resin cements and a bonded resin cement for crowns bonded to extracted teeth with preparations having a total taper greater than 30 degrees. A crown pull-off test was used with direction of pull along the path of insertion. The CAD/CAM system Cerec was used to create crowns with the pull-off loop as an integral part of the crown structure. One hundred extracted human molars were prepared for all-ceramic crowns with a 1.5-mm shoulder, greater than 30-degree axial wall convergence, a flat occlusal surface and 3 to 5 mm occlusal/ gingival height. All-ceramic crowns were cemented with five different self-adhesive cements (Rely X Unicem, Maxcem Elite, BisCem, SmartCem 2, and G-Cem) and one bonded resin cement (Multilink). Forfour cements (excluding GCem and Multilink) there were 2 groups, one with HF etching and one without ceramic surface treatment. The crowns were then subject to tensile stress until either the crown fractured or the crown was lifted off from the tooth. For several cements, the bond strength exceeded the tensile strength of the all-ceramic crown; thus, the crown fractured, leaving the cemented part of the crown on the tooth. The effect of ceramic surface etching was not statistically significant at p = 0.05; however, for each cement, the treated crowns showed a lower coefficient of variance (COV). For this study, the COV ranged from 24.9 % to 97.9 %. Loads ranged from 41.3 to 190.3 N. Some of the new self-etching resin cements can create bonds to non-retentive crown preparations that are stronger than the strength of a ceramic crown; however, these high bond strengths may not be able to be achieved consistently.

  19. Using High Spatial Resolution Satellite Imagery to Map Forest Burn Severity Across Spatial Scales in a Pine Barrens Ecosystem

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    Meng, Ran; Wu, Jin; Schwager, Kathy L.; Zhao, Feng; Dennison, Philip E.; Cook, Bruce D.; Brewster, Kristen; Green, Timothy M.; Serbin, Shawn P.

    2017-01-01

    As a primary disturbance agent, fire significantly influences local processes and services of forest ecosystems. Although a variety of remote sensing based approaches have been developed and applied to Landsat mission imagery to infer burn severity at 30 m spatial resolution, forest burn severity have still been seldom assessed at fine spatial scales (less than or equal to 5 m) from very-high-resolution (VHR) data. We assessed a 432 ha forest fire that occurred in April 2012 on Long Island, New York, within the Pine Barrens region, a unique but imperiled fire-dependent ecosystem in the northeastern United States. The mapping of forest burn severity was explored here at fine spatial scales, for the first time using remotely sensed spectral indices and a set of Multiple Endmember Spectral Mixture Analysis (MESMA) fraction images from bi-temporal - pre- and post-fire event - WorldView-2 (WV-2) imagery at 2 m spatial resolution. We first evaluated our approach using 1 m by 1 m validation points at the sub-crown scale per severity class (i.e. unburned, low, moderate, and high severity) from the post-fire 0.10 m color aerial ortho-photos; then, we validated the burn severity mapping of geo-referenced dominant tree crowns (crown scale) and 15 m by 15 m fixed-area plots (inter-crown scale) with the post-fire 0.10 m aerial ortho-photos and measured crown information of twenty forest inventory plots. Our approach can accurately assess forest burn severity at the sub-crown (overall accuracy is 84% with a Kappa value of 0.77), crown (overall accuracy is 82% with a Kappa value of 0.76), and inter-crown scales (89% of the variation in estimated burn severity ratings (i.e. Geo-Composite Burn Index (CBI)). This work highlights that forest burn severity mapping from VHR data can capture heterogeneous fire patterns at fine spatial scales over the large spatial extents. This is important since most ecological processes associated with fire effects vary at the less than 30 m scale and

  20. Demonstration of a crown ether process for partitioning strontium from high level liquid waste (HLLW)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianchen; Jing, Shan; Chen, Jing [Tsinghua Univ., Beijing (China). Inst. of Nuclear and New Energy Technology (INET); Tsinghua Univ., Beijing (China). Beijing Key Lab of Radioactive Waste Treatment

    2016-05-01

    Chinese HLLW with a higher-salt liquid that was generated via plutonium uranium recovery by extraction (PUREX) processing was temporarily stored in stainless steel tanks and is waiting for treatment. The volume and heat-loading of the glass block are reduced if the strontium, cesium, actinides and other long-life radioactive elements, such as Tc in the HLLW, are partitioned before the HLLW verification. This process is beneficial to preserve the capacity of the geological disposal repository and to minimize long-term hazards. The process of partitioning strontium from Chinese HLLW using Dicyclohexano-18Crown-6(DCH18C-6) was developed in past decades, including such fundamental studies as the small scale cold and hot test. In this work, new studies are introduced, including the cold and the long time hot cascade tests, using a miniature centrifugal contactor set and the pilot-scale cold test using pulse extraction columns. The results indicate that the crown process is promising for partitioning strontium from Chinese HLLW.

  1. Cesium-133 NMR studies of crown ether-Cs sup + complexes in high dielectric amide solvents

    Energy Technology Data Exchange (ETDEWEB)

    Soong, Lee-Lin; Leroi, G.E.; Popov, A.I. (Michigan State Univ., East Lansing (USA))

    1990-04-04

    Cesium-133 chemical shift and spin-lattice relaxation time measurements have been used to determine formation constants of the cesium ion complexes with 11 crown ethers, 15C5, 18C6, 21C7, DA18C6, DB18C6, DC18C6, DB21C7, DB24C8, DB27C9, DC21C7, and DC24C8, in formamide, N-methylformamide, dimethylormamide, and dimethylacetamide solutions. In the cases of 15C5, 18C6, DC21C7, and DC24C8, both LCs{sup +} and L{sub 2}Cs{sup +} complexes (L = crown ether) were observed; in all other systems only 1:1 complexes were formed. The formation of L{sub 2}Cs{sup +} complexes with DC21C7 and DC24C8 is surprising since both ligand cavities are larger than the cesium cation; previously, it was expected that only 1:1 complexes would form under such circumstances. In addition to the match between the cation diameter and ligand cavity, such factors as solvation of the complexation partners and the structure of the solvent itself affect the stability of the macrocycle-cation complexes. The selected amide solvents have similar donicities and dipole moments; in general, consistent with expectations for ion-dipole interactions, the calculated stability constants were larger in the lower dielectric constant media. 23 refs., 9 figs., 4 tabs.

  2. [Effects of different tooth preparations on the fracture behavior of teeth with severe wedge-shaped defect restored with post and core crowns].

    Science.gov (United States)

    Feng, Dandan; Qi, Dong; Lin, Xuefen; Ding, Tingting; Ji, Ping

    2014-04-01

    This study aimed to investigate the effects of different tooth preparations on the fracture strength and pattern of failure of teeth with severe wedge-shaped defect restored with post and core crowns. According to whether the teeth above the wedge-shaped defect was removed (represented by B) or not (represented by A), the ferrule next to the wedge-shaped defect was prepared (represented by D) or not (represented by C), the cast post-and-core was chosen (represented by E) or glass-fiber post and resin core was chosen (represented by F). A total of 64 human mandibular premolar teeth were randomly divided into 8 groups: A1-1 (A + C + E), A1-2 (A + C + F), A2-1 (A + D + E), A2-2 (A + D + F), B1-1 (B + C + E), B1-2 (B + C + F), B2-1 (B + D + E), B2-2 (B + D + F), each group 8 teeth. All the teeth were prepared and restored accordingly and then mounted on an electronic pressure universal testing machine. The maximum fracture strength and the patterns of failure were recorded. 1) The fracture strength of Group A1-1 > that of Group B1-1, Group A1-2 > Group B1-2, Group B2-1 > Group B1-1, and Group B2-1 > Group B2-2 with significant differences (P crown. The ferrule of the wedge-shaped defect is not recommended to be prepared. Furthermore, the glass-fiber post and resin core is favorable for the re-repair of the teeth than the cast post and core.

  3. Variation in Incidence and Severity of Injuries among Crown-of-Thorns Starfish (Acanthaster cf. solaris on Australia’s Great Barrier Reef

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    Vanessa Messmer

    2017-02-01

    Full Text Available Despite the presence of numerous sharp poisonous spines, adult crown-of-thorns starfish (CoTS are vulnerable to predation, though the importance and rates of predation are generally unknown. This study explores variation in the incidence and severity of injuries for Acanthaster cf. solaris from Australia’s Great Barrier Reef. The major cause of such injuries is presumed to be sub-lethal predation such that the incidence of injuries may provide a proxy for overall predation and mortality rates. A total of 3846 Acanthaster cf. solaris were sampled across 19 reefs, of which 1955 (50.83% were injured. Both the incidence and severity of injuries decreased with increasing body size. For small CoTS (<125 mm total diameter >60% of individuals had injuries, and a mean 20.7% of arms (±2.9 SE were affected. By comparison, <30% of large (>450 mm total diameter CoTS had injuries, and, among those, only 8.3% of arms (±1.7 SE were injured. The incidence of injuries varied greatly among reefs but was unaffected by the regulations of local fisheries.

  4. Design and Development of Highly Potent HIV-1 Protease Inhibitors with a Crown-Like Oxotricyclic Core as the P2-Ligand To Combat Multidrug-Resistant HIV Variants.

    Science.gov (United States)

    Ghosh, Arun K; Rao, Kalapala Venkateswara; Nyalapatla, Prasanth R; Osswald, Heather L; Martyr, Cuthbert D; Aoki, Manabu; Hayashi, Hironori; Agniswamy, Johnson; Wang, Yuan-Fang; Bulut, Haydar; Das, Debananda; Weber, Irene T; Mitsuya, Hiroaki

    2017-05-25

    Design, synthesis, and evaluation of a new class of exceptionally potent HIV-1 protease inhibitors are reported. Inhibitor 5 displayed superior antiviral activity and drug-resistance profiles. In fact, this inhibitor showed several orders of magnitude improved antiviral activity over the FDA approved drug darunavir. This inhibitor incorporates an unprecedented 6-5-5 ring-fused crown-like tetrahydropyranofuran as the P2 ligand and an aminobenzothiazole as the P2' ligand with the (R)-hydroxyethylsulfonamide isostere. The crown-like P2 ligand for this inhibitor has been synthesized efficiently in an optically active form using a chiral Diels-Alder catalyst providing a key intermediate in high enantiomeric purity. Two high resolution X-ray structures of inhibitor-bound HIV-1 protease revealed extensive interactions with the backbone atoms of HIV-1 protease and provided molecular insight into the binding properties of these new inhibitors.

  5. Proximity to a high traffic road: glucocorticoid and life history consequences for nestling white-crowned sparrows.

    Science.gov (United States)

    Crino, O L; Van Oorschot, B Klaassen; Johnson, E E; Malisch, J L; Breuner, C W

    2011-09-01

    Roads have been associated with decreased reproductive success and biodiversity in avian communities and increased physiological stress in adult birds. Alternatively, roads may also increase food availability and reduce predator pressure. Previous studies have focused on adult birds, but nestlings may also be susceptible to the detrimental impacts of roads. We examined the effects of proximity to a road on nestling glucocorticoid activity and growth in the mountain white-crowned sparrow (Zonotrichia leucophrys oriantha). Additionally, we examined several possible indirect factors that may influence nestling corticosterone (CORT) activity secretion in relation to roads. These indirect effects include parental CORT activity, nest-site characteristics, and parental provisioning. And finally, we assessed possible fitness consequences of roads through measures of fledging success. Nestlings near roads had increased CORT activity, elevated at both baseline and stress-induced levels. Surprisingly, these nestlings were also bigger. Generally, greater corticosterone activity is associated with reduced growth. However, the hypothalamic-pituitary-adrenal axis matures through the nestling period (as nestlings get larger, HPA-activation is greater). Although much of the variance in CORT responses was explained by body size, nestling CORT responses were higher close to roads after controlling for developmental differences. Indirect effects of roads may be mediated through paternal care. Nestling CORT responses were correlated with paternal CORT responses and paternal provisioning increased near roads. Hence, nestlings near roads may be larger due to increased paternal attentiveness. And finally, nest predation was higher for nests close to the road. Roads have apparent costs for white-crowned sparrow nestlings--increased predation, and apparent benefits--increased size. The elevation in CORT activity seems to reflect both increased size (benefit) and elevation due to road

  6. Extracting forest canopy structure from spatial information of high resolution optical imagery: tree crown size versus leaf area index

    Science.gov (United States)

    C. Song; M.B. Dickinson

    2008-01-01

    Leaves are the primary interface where energy, water and carbon exchanges occur between the forest ecosystems and the atmosphere. Leaf area index (LAI) is a measure of the amount of leaf area in a stand, and the tree crown size characterizes how leaves are clumped in the canopy. Both LAI and tree crown size are of essential ecological and management value. There is a...

  7. Identification, introgression, and molecular marker genetic analysis and selection of a highly effective novel oat crown rust resistance from diploid oat, Avena strigosa

    Science.gov (United States)

    A new highly effective resistance to oat crown rust (Puccinia coronata f. sp. avenae) was identified in the diploid oat Avena strigosa PI 258731 and introgressed into hexaploid cultivated oat. Young plants with this resistance show moderate susceptibility, whereas older plant tissues and adult plant...

  8. Detection of a High-Density Brachiolaria-Stage Larval Population of Crown-of-Thorns Sea Star (Acanthaster planci in Sekisei Lagoon (Okinawa, Japan

    Directory of Open Access Journals (Sweden)

    Go Suzuki

    2016-03-01

    Full Text Available Outbreaks of the crown-of-thorns sea star (Acanthaster planci are likely to be strongly associated with drastic changes in larval survival influenced by food availability. However, no quantitative or qualitative data are available on the distribution of A. planci larvae in the field nor on the environmental factors that influence their survivorship. Here we use a DNA barcoding approach to describe the distribution of A. planci larvae in Sekisei Lagoon, Ryukyu Archipelago, Japan after conducting three days of high-intensity sampling. High densities (53.3 individuals/m3 of A. planci larvae were found outside of Yonara Channel, which is the largest reef channel in this lagoon. Surprisingly, most (94% of the aggregated larvae were advanced-stage brachiolaria. Considering that it takes several days to develop to this stage, this result demonstrates that A. planci larvae were floating for some time and maintaining a high-density population. However, this dense larval cloud disappeared immediately after a typhoon. No spatial correlation was found between larval density and either nutrient or chlorophyll a concentrations, suggesting that A. planci larvae do not necessarily aggregate in nutrient-rich water. These data suggest that some high-density populations of late developmental stage A. planci larvae were produced under a low phytoplankton concentration and could potentially trigger an adult outbreak. Consequently, our data suggest that adult outbreaks may not necessarily be triggered by food availability alone.

  9. High-Resolution Airborne UAV Imagery to Assess Olive Tree Crown Parameters Using 3D Photo Reconstruction: Application in Breeding Trials

    Directory of Open Access Journals (Sweden)

    Ramón A. Díaz-Varela

    2015-04-01

    Full Text Available The development of reliable methods for the estimation of crown architecture parameters is a key issue for the quantitative evaluation of tree crop adaptation to environment conditions and/or growing system. In the present work, we developed and tested the performance of a method based on low-cost unmanned aerial vehicle (UAV imagery for the estimation of olive crown parameters (tree height and crown diameter in the framework of olive tree breeding programs, both on discontinuous and continuous canopy cropping systems. The workflow involved the image acquisition with consumer-grade cameras on board a UAV and orthomosaic and digital surface model generation using structure-from-motion image reconstruction (without ground point information. Finally, geographical information system analyses and object-based classification were used for the calculation of tree parameters. Results showed a high agreement between remote sensing estimation and field measurements of crown parameters. This was observed both at the individual tree/hedgerow level (relative RMSE from 6% to 20%, depending on the particular case and also when average values for different genotypes were considered for phenotyping purposes (relative RMSE from 3% to 16%, pointing out the interest and applicability of these data and techniques in the selection scheme of breeding programs.

  10. Fracture resistance of zirconia-composite veneered crowns in comparison with zirconia-porcelain crowns.

    Science.gov (United States)

    Alsadon, Omar; Patrick, David; Johnson, Anthony; Pollington, Sarah; Wood, Duncan

    2017-05-31

    The objectives were to evaluate the fracture resistance and stress concentration in zirconia/composite veneered crowns in comparison to zirconia/porcelain crowns using occlusal fracture resistance and by stress analysis using finite element analysis method. Zirconia substructures were divided into two groups based on the veneering material. A static load was applied occlusally using a ball indenter and the load to fracture was recorded in Newtons (N). The same crown design was used to create 3D crown models and evaluated using FEA. The zirconia/composite crowns subjected to static occlusal load showed comparable results to the zirconia/porcelain crowns. Zirconia/composite crowns showed higher stress on the zirconia substructure at 63.6 and 50.9 MPa on the zirconia substructure veneered with porcelain. In conclusion, zirconia/composite crowns withstood high occlusal loads similar to zirconia/porcelain crowns with no significant difference. However, the zirconia/composite crowns showed higher stress values than the zirconia/porcelain crowns at the zirconia substructure.

  11. Larvae of the coral eating crown-of-thorns starfish, Acanthaster planci in a warmer-high CO2 ocean.

    Science.gov (United States)

    Kamya, Pamela Z; Dworjanyn, Symon A; Hardy, Natasha; Mos, Benjamin; Uthicke, Sven; Byrne, Maria

    2014-11-01

    Outbreaks of crown-of-thorns starfish (COTS), Acanthaster planci, contribute to major declines of coral reef ecosystems throughout the Indo-Pacific. As the oceans warm and decrease in pH due to increased anthropogenic CO2 production, coral reefs are also susceptible to bleaching, disease and reduced calcification. The impacts of ocean acidification and warming may be exacerbated by COTS predation, but it is not known how this major predator will fare in a changing ocean. Because larval success is a key driver of population outbreaks, we investigated the sensitivities of larval A. planci to increased temperature (2-4 °C above ambient) and acidification (0.3-0.5 pH units below ambient) in flow-through cross-factorial experiments (3 temperature × 3 pH/pCO2 levels). There was no effect of increased temperature or acidification on fertilization or very early development. Larvae reared in the optimal temperature (28 °C) were the largest across all pH treatments. Development to advanced larva was negatively affected by the high temperature treatment (30 °C) and by both experimental pH levels (pH 7.6, 7.8). Thus, planktonic life stages of A. planci may be negatively impacted by near-future global change. Increased temperature and reduced pH had an additive negative effect on reducing larval size. The 30 °C treatment exceeded larval tolerance regardless of pH. As 30 °C sea surface temperatures may become the norm in low latitude tropical regions, poleward migration of A. planci may be expected as they follow optimal isotherms. In the absence of acclimation or adaptation, declines in low latitude populations may occur. Poleward migration will be facilitated by strong western boundary currents, with possible negative flow-on effects on high latitude coral reefs. The contrasting responses of the larvae of A. planci and those of its coral prey to ocean acidification and warming are considered in context with potential future change in tropical reef ecosystems.

  12. The use of stainless steel crowns.

    Science.gov (United States)

    Seale, N Sue

    2002-01-01

    The stainless steel crown (SSC) is an extremely durable restoration with several clear-cut indications for use in primary teeth including: following a pulpotomy/pulpectomy; for teeth with developmental defects or large carious lesions involving multiple surfaces where an amalgam is likely to fail; and for fractured teeth. In other situations, its use is less clear cut, and caries risk factors, restoration longevity and cost effectiveness are considerations in decisions to use the SSC. The literature on caries risk factors in young children indicates that children at high risk exhibiting anterior tooth decay and/or molar caries may benefit by treatment with stainless steel crowns to protect the remaining at-risk tooth surfaces. Studies evaluating restoration longevity, including the durability and lifespan of SSCs and Class II amalgams demonstrate the superiority of SSCs for both parameters. Children with extensive decay, large lesions or multiple surface lesions in primary molars should be treated with stainless steel crowns. Because of the protection from future decay provided by their feature of full coverage and their increased durability and longevity, strong consideration should be given to the use of SSCs in children who require general anesthesia. Finally, a strong argument for the use of the SSC restoration is its cost effectiveness based on its durability and longevity.

  13. Comparative photophysical behaviour of naphthalene-linked crown ...

    Indian Academy of Sciences (India)

    TECS

    Abstract. A comparative time-resolved emission studies of several naphtho-crown ethers I–V, where metal ions can be complexed in a predetermined orientation with respect to the naphthalene (Naph) π- plane and naphthalene-linked aza crown ethers (L1 and L2) have been presented. In both the systems, crown ethers ...

  14. Thinning guidelines from crown area relationships for young hardwood plantations

    Science.gov (United States)

    Jeffrey W. Stringer; Luke Cecil

    2010-01-01

    Crown closure in hardwood plantations signals the first opportunity to apply density control treatments such as thinning or release. The proper timing of these treatments is a function of stocking levels and is generally scheduled within several years after initial crown closure. Predicting crown closure for a plantation provides practitioners with the ability to plan...

  15. Coast redwood live crown and sapwood

    Science.gov (United States)

    John-Pascal Berrill; Jesse L. Deffress; Jessica M. Engle

    2012-01-01

    Understanding crown rise and sapwood taper will help meet management objectives such as producing long branch-free boles for clear wood and old-growth restoration, or producing sawlogs with a high proportion of heartwood. Coast redwood (Sequoia sempervirens) tree crown ratio data were collected 20 years after partial harvesting in a 65-year-old second growth stand....

  16. Clinical Evaluation and Parental Satisfaction with Pediatric Zirconia Anterior Crowns.

    Science.gov (United States)

    Holsinger, Daniel M; Wells, Martha H; Scarbecz, Mark; Donaldson, Martin

    2016-01-01

    The purpose of this study was to evaluate the clinical success of and parental satisfaction with anterior pediatric zirconia crowns. A retrospective analysis of maxillary anterior pediatric zirconia crowns was performed. Crowns were evaluated for retention, gingival health, color match, contour, marginal integrity, and opposing tooth wear. Parental satisfaction regarding the esthetics of the crowns and parental perception of the impact of treatment on the child's appearance and oral health were evaluated by questionnaire. Fifty-seven crowns were evaluated in 18 children. Eight teeth were lost to exfoliation, three were extracted due to pathology, and two crowns debonded, leaving 44 available for examination. The average crown age at time of examination was 20.8 months. Sixteen crowns (36 percent) displayed gingival inflammation and color mismatch. No recurrent caries or opposing tooth wear was noted. Parents reported high satisfaction with the color, size, and shape of the crowns. The majority of parents reported that crowns improved the appearance and oral health of their child (78 percent and 83 percent, respectively). Eight-nine percent of parents reported that they would highly recommend these crowns. Zirconia crowns are clinically acceptable restorations in the primary maxillary anterior dentition. Parental satisfaction with zirconia crowns is high.

  17. Koreksi dimensi vertikal oklusal dengan modifikasi restorasi mahkota logam pada kasus severe early childhood caries (Correcting occlusal vertical dimension using modified stainless steel crown restoration in severe early childhood caries case

    Directory of Open Access Journals (Sweden)

    Amrita Widyagarini

    2014-06-01

    Full Text Available Background: Severe early childhood caries (SECC describes progressively dental caries in primary dentition among children aged less than 3 to 5-year-old. Loss of Occlusal Vertical Dimension (OVD with deep bite in clinical feature found 2.5 times more often in s-ecc children than others. It leads discrepancies of vertical development of permanent dentition, hence creates malocclusion. Purpose: The aim of this paper was to report consideration and correction of OVD in SECC child. Case: A 5-year-old girl was accompanied by her mother came to pediatric dental clinic Faculty of Dentistry Universitas Indonesia. Patient’s chief complaint was decay on all her teeth. Clinical examination revealed caries on all primary dentition, tooth #16, #46 have not yet been occluded, 26 erupted partially and it occluded with 36, anterior deep bite. Diagnose was anterior deep bite caused by SECC. Case management: Operative-rehabilitative treatment restores OVD to prevent malocclusion by modifying height of ssc in primary molars. Correcting deep bite using stainless steel crown (SSC modified in posterior was done. First, restoration with glass-ionomer cement for raising the bite followed by a week evaluation to observe masticatory function and functional analysis of temporomandibular joint. Second, ssc were placed in primary molars. Conclusion: Modifying height of ssc in primary molars could corrected OVD in SECC child. Permanent first molars eruption could be guided to completely occlusion and prevent early malocclusion.Latar belakang: Severe early childhood caries (SECC menunjukan pola karies gigi sulung yang progresif dan menyeluruh pada anak usia di bawah 3 hingga 5 tahun. Kehilangan dimensi vertikal oklusal (DVO, dengan gambaran gigitan dalam pada periode gigi sulung dilaporkan terjadi 2,5 kali lebih banyak pada anak SECC. Hal ini dapat menyebabkan gangguan perkembangan vertikal gigi permanen yang nantinya menyebabkan maloklusi. Tujuan: Laporan kasus ini

  18. Comparative in vivo evaluation of restoring severely mutilated primary anterior teeth with biological post and crown preparation and reinforced composite restoration

    Directory of Open Access Journals (Sweden)

    Grewal N

    2008-01-01

    Full Text Available Background: This study was designed to compare the success rate of biological and composite restorations when used to replace structural loss of primary anterior teeth using intracanal post for radicular support of the restoration. Materials and Methods: Forty-two patients aged between 3-5 years presenting with early childhood caries (ECC received at least one or more composite and biological restorations for comparative evaluation. A total of 150 restorations were done (75 biological restorations and 75 composite restorations. The restorations were evaluated single-blind according to a modified USPHS system. Assessment of the patient′s response in accepting a biological restoration, psychological impact of the restorations, view of the parents, and peer group reviews, etc. were recorded in a response sheet in presence of the child and the parents. Observations and Results: In vivo clinical performance of biological post and crown restorations and intracanal reinforced composite restorations was comparable with respect to shade match, marginal discoloration, marginal integrity, surface finish, gingival health, retention, and recurrent carious lesions. The cost effectiveness of biological restorations was certainly a positive attribute. Conclusion: The biological restoration presented as a cost effective, clinician friendly, less-technique sensitive, and esthetic alternative to commercially available restorative materials used for restoring deciduous teeth affected by ECC.

  19. Clinical assessment of class II resin-based composites versus preformed metal crowns performed on primary molars in patients at high risk of caries.

    Science.gov (United States)

    Alyahya, A; Khanum, A; Qudeimat, M

    2018-02-01

    To compare class II resin composite with preformed metal crowns (PMC) in the treatment of proximal dentinal caries in high caries-risk patients. The charts (270) of paediatric patients with proximal caries of their primary molars were reviewed. Success or failure of a procedure was assessed using the dental notes. Survival analysis was used to calculate the mean survival time (MST) for both procedures. The influence of variables on the mean survival time was investigated. A total of 593 class II resin composites and 243 PMCs were placed in patients ranging between 4-13 years of age. The failure percentage of class II resin composites was 22.6% with the majority having been due to recurrent caries, while the failure percentage of PMCs was 15.2% with the majority due to loss of the crown. There was no significant difference between the MST of class II resin composites and PMCs, 41.3 and 45.6 months respectively (p value = 0.06). In class II resin composites, mesial restorations were associated with lower MST compared to distal restorations (p-value composites and PMCs were comparable when performed on high caries-risk patients.

  20. [Three-dimensional data fusion method for tooth crown and root based on curvature continuity algorithm].

    Science.gov (United States)

    Zhao, Y J; Liu, Y; Sun, Y C; Wang, Y

    2017-08-18

    To explore a three-dimensional (3D) data fusion and integration method of optical scanning tooth crowns and cone beam CT (CBCT) reconstructing tooth roots for their natural transition in the 3D profile. One mild dental crowding case was chosen from orthodontics clinics with full denture. The CBCT data were acquired to reconstruct the dental model with tooth roots by Mimics 17.0 medical imaging software, and the optical impression was taken to obtain the dentition model with high precision physiological contour of crowns by Smart Optics dental scanner. The two models were doing 3D registration based on their common part of the crowns' shape in Geomagic Studio 2012 reverse engineering software. The model coordinate system was established by defining the occlusal plane. crown-gingiva boundary was extracted from optical scanning model manually, then crown-root boundary was generated by offsetting and projecting crown-gingiva boundary to the root model. After trimming the crown and root models, the 3D fusion model with physiological contour crown and nature root was formed by curvature continuity filling algorithm finally. In the study, 10 patients with dentition mild crowded from the oral clinics were followed up with this method to obtain 3D crown and root fusion models, and 10 high qualification doctors were invited to do subjective evaluation of these fusion models. This study based on commercial software platform, preliminarily realized the 3D data fusion and integration method of optical scanning tooth crowns and CBCT tooth roots with a curvature continuous shape transition. The 10 patients' 3D crown and root fusion models were constructed successfully by the method, and the average score of the doctors' subjective evaluation for these 10 models was 8.6 points (0-10 points). which meant that all the fusion models could basically meet the need of the oral clinics, and also showed the method in our study was feasible and efficient in orthodontics study and clinics

  1. Crown Fire Potential

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Crown fire potential was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The...

  2. Development of high-performance ion sensors based on the functions of crown ethers and synthetic bilayer membranes; Kurauneteru oyobi goseinibunshimaku no kino wo kiban to shita koseino ion denkyoku no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yanagi, H.; Sakai, T.; Ogata, T. [Tokuyama Corp., Tokyo (Japan)

    1999-10-10

    High-Performance Na{sup +}, K{sup +} and Cl{sup -} ion selective electrodes (ISEs) are reported. These are based on a new concept, which is an ion recognition site formed by molecular interaction. In the case of Na and K ISEs, crown ether compounds connecting with planar substituents were used as the ionophores. The selectivities depend on the structure of substituents. It is found that the intermolecular interaction of the planar substituent plays an important role on the improvement of selectivity. The selectivities of interactive mono (crown ether) are equal to that of bis (crown ether). It means that ion recognition site like a bis (crown ether) is formed by the interaction of mono (crown ehter)s. In the case of C1 ISE, immobilized synthetic bilayer membrane with quaternary ammonium salts was used as the ion sensitive membrane. in the immobilized synthetic bilayer membrane, ordered molecular aggregates is formed. It is found that the molecular orientation improved the Cl selectivity. The insufficient selectivity over lipophilic anions can be addition of alphatic alcohol. These resulting ISEs exhibit high speed response and long life time, and they are applicable to clinical use which demands both accurate measurement and high speed processing. (author)

  3. Colorimetric values of esthetic stainless steel crowns.

    Science.gov (United States)

    Hosoya, Yumiko; Omachi, Koichi; Staninec, Michal

    2002-01-01

    The colorimetric values of two different kinds of esthetic stainless steel crowns were measured and compared with the colorimetric values of primary anterior teeth in Japanese children. The colorimetric values of resin composite-faced stainless steel crowns (Kinder Krown) and epoxy-coated stainless steel crowns (White Steel Crown) were measured with a color difference meter. The Commission Internationale de Eclairage L*, a*, b*, and delta E*ab values and Munsell value, chroma, and hue were calculated. The data were compared with previously reported colorimetric values of Japanese primary anterior teeth measured with the same color difference meter used in this study. Compared to Japanese primary anterior teeth, Kinder Krown Pedo I and Pedo II showed much higher L* values and lower hue; on the other hand, White Steel Crown showed much higher L*, a*, b* values, much higher value and chroma, and much lower hue. Color analysis revealed that the colors of the White Steel Crown and Kinder Krown Pedo I were substantially different from the color of Japanese primary anterior teeth. The color difference between Pedo II crowns and Japanese primary anterior teeth was relatively high, but the color of Pedo II might be acceptable for clinical use.

  4. Aesthetic preformed paediatric crowns: systematic review.

    Science.gov (United States)

    Aiem, Elody; Smaïl-Faugeron, Violaine; Muller-Bolla, Michèle

    2017-07-01

    Different aesthetic preformed crowns (APC) are proposed to restore decayed and damaged primary teeth because the stainless steel crowns (SSCs) do not satisfy parents concerned about aesthetic. The objective was to evaluate the clinical effectiveness of all types of APC for restoring primary teeth compared with conventional filling materials or other types of crowns. Relevant articles were searched in electronic databases of PubMed via MEDLINE and the Cochrane central register of controlled trials. Two review authors independently assessed the risk of bias in the included articles and extracted data. From 555 potentially eligible articles, seven relevant articles were included. The overall risk of bias was high for all the studies. SCCs cannot be replaced by APC, such as the open-faced SSCs and the pre-veneered SCCs, for restoring badly decayed primary molars. Zircon crowns were assessed only in primary incisors and compared with pre-veneered SCCs and resin composite strip crowns. After a follow-up of only 6 months, Zircon crowns gave significantly better results than the others with regard to gingival health and crown fractures. Due to the small number of RCTs on this topic and their risk of bias, future RCTs should be carried out in primary teeth. © 2016 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Pre-restorative crown lengthening surgery outcomes: a systematic review.

    Science.gov (United States)

    Pilalas, Ioannis; Tsalikis, Lazaros; Tatakis, Dimitris N

    2016-12-01

    Pre-restorative crown lengthening surgery (CLS) is a common periodontal procedure, for which systematic reviews are lacking. This systematic review aimed to assess outcomes of CLS performed for restorative reasons. Databases (MEDLINE, Scopus, OpenGrey) were searched up to January 2016 for clinical/animal trials on CLS for restorative reasons with ≥6-month follow-up. Primary outcomes investigated were: free gingival margin position, probing depth, clinical attachment level, and plaque/inflammation indices. Four non-randomized and one randomized controlled clinical trial and one controlled animal trial were included. Heterogeneity and high risk of bias were identified. CLS resulted in increased crown length (6-month average: 1.4-3.3 mm). Between immediate postsurgery and follow-up, gingival margin may rebound, largely during the first three postoperative months. Technical (flap positioning, osseous resection, root preparation) and anatomical (periodontal biotype) factors influence outcomes. The literature lacks studies on tooth mobility, crown-root ratio, patient- and referring dentist-reported outcomes, surgical technique comparisons, and restorative treatment timing. Within the available data limitations, it is concluded that CLS results in increased crown length and possible gingival margin rebound. Technical aspects (primarily) and anatomical factors (secondarily) influence outcomes. Future research is needed to fill significant voids in our knowledge on several procedural aspects. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Identification, introgression, and molecular marker genetic analysis and selection of a highly effective novel oat crown rust resistance from diploid oat, Avena strigosa.

    Science.gov (United States)

    Rines, Howard W; Miller, Marisa E; Carson, Martin; Chao, Shiaoman; Tiede, Tyler; Wiersma, Jochum; Kianian, Shahryar F

    2018-03-01

    Oat crown rust is one of the most damaging diseases of oat. We identified a new source of resistance and developed KASP and TaqMan markers for selection in breeding programs. A new highly effective resistance to oat crown rust (Puccinia coronata f. sp. avenae) was identified in the diploid oat Avena strigosa PI 258731 and introgressed into hexaploid cultivated oat. Young plants with this resistance show moderate susceptibility, whereas older plant tissues and adult plants are resistant with no virulent isolates encountered in over 8 years of testing. Resistance was incorporated into hexaploid oat by embryo rescue, colchicine chromosome doubling followed by backcrosses with a hexaploid parent, and selection for stable transmission of resistance. To mitigate flag leaf and panicle chlorosis/necrosis associated with the resistance, crosses were made with derived resistant lines to breeding lines of divergent parentage followed by selection. Subsequently, two F 2 sister lines, termed MNBT1020-1 and MNBT1021-1, were identified in which the chlorosis/necrosis was reduced. These two lines performed well in replicated multi-location state trials in 2015 and 2016 out-yielding all cultivar entries. Segregating F 2:3 plants resulting from crosses of MNBT lines to susceptible parents were genotyped with the oat 6K SNP array, and SNP loci with close linkage to the resistance were identified. KASP assays generated from linked SNPs showed accurate discrimination of the resistance in derivatives of the resistant MNBT lines crossed to susceptible breeding lines. A TaqMan marker was developed and correctly identified homozygous resistance in over 95% of 379 F 4 plants when rust was scored in F 4:5 plants in the field. Thus, a novel highly effective resistance and associated molecular markers are available for use in breeding, genetic analysis, and functional studies.

  7. In Vitro Analysis of the Tribological Behaviour of Different Material Combinations for Telescopic Crowns

    Directory of Open Access Journals (Sweden)

    Wigbert Linek

    2016-06-01

    Full Text Available Telescopic crowns are used to connect removable dental prostheses with the remaining dentition. Several material combinations are used for manufacturing primary and secondary crowns. The present experimental study analysed the influence of different material combinations on the long-term development of surface roughness and pull-off forces. Six different material combinations were tested. Secondary crowns were manufactured either by casting or electroforming. Each material combination was tested with n = 10 specimens. A material testing device with integrated power sensors was used for 10,000 cycles per test. Signs of wear were identified by surface roughness measurements, and visualized by a scanning electron microscope (SEM and X-ray spectroscopy (EDX technologies. Statistical significances were tested by using the U-Test with Bonferroni correction. The choice of materials and the manufacturing process were found to influence the long-term development of pull-off forces as well as wear-associated surface roughness. Combinations of different groups of materials for primary and secondary crowns showed favourable results. Worse results were found for the combination pure titanium and pure titanium and the combination high gold alloy and electroformed gold. Wear-associated surface roughness was higher for combinations of similar or identical groups of materials. For manufacturing telescopic crowns, combinations of different groups of materials are preferred. For secondary crown manufacturing, electroforming is superior to casting.

  8. Correlation of flexural strength of coupons versus strength of crowns fabricated with different zirconia materials with and without aging.

    Science.gov (United States)

    Alghazzawi, Tariq F; Janowski, Gregg M

    2015-12-01

    The purpose of this study was to determine the presence of a correlation between flexural strength and simulated crown strength; a correlation between crown strength and mode of fracture; an effect of aging on the flexural strength; and an effect of aging on the crown strength. Two hundred forty zirconia specimens were fabricated with 2 different designs, fully contoured crown shape specimens (n = 120) and rectangular coupons (n = 120), to provide 10 specimens each of 6 brands of zirconia (Lava Plus High Translucency [3M ESPE], Argen HT [Argen Corp], Zirlux [Ardent], BruxZir [Glidewell Laboratories], ZenoStar [Wieland Dental], and DDBioZX(2) [Dental Direkt]). One-half of each sample type was given a severe, simulated low-temperature aging treatment. The coupons were tested by 3-point flexural strength, and crowns were tested after luting to metallic abutments using resin cement. Statistical significance was evaluated by 2-factor analysis of variance (P = .05). Aging increased the mean (standard deviation [SD]) flexural strength for the following groups: Argen HT (995 [140] megapascals versus 677 [121] MPa before aging), Zirlux (939 [101] MPa versus 826 [169] MPa before aging), and ZenoStar (954 [81] MPa versus 764 [77] MPa before aging). There were statistical differences for the mean (SD) crown strengths for the following aged crowns: DDBioZX(2) had higher magnitudes (9,755 [1,095] MPa) than ZenoStar (8,864 [976] MPa), whereas Lava Plus High Translucency crowns had higher magnitudes (9,871 [942] MPa) than ZenoStar (8,864 [976] MPa). There was no effect of aging on the crown strength. There were statistical differences in the mode of fracture for the zirconia crowns between the following groups: nonaged and aged BruxZir (P = .014), nonaged and aged ZenoStar (P = .0226), and nonaged and aged Lava Plus High Translucency (P crown strength. There was no direct correlation between ranking of flexural strength and crown strength in the range of properties exhibited by

  9. Fracture strength of ceramic monolithic crown systems of different thickness.

    Science.gov (United States)

    Nordahl, Niklas; Vult von Steyern, Per; Larsson, Christel

    2015-09-01

    The objective of this study was to evaluate fracture strength of high-translucent (HTZ) and low-translucent (LTZ) zirconia and glass-ceramic (LDS) crowns. HTZ and LTZ crowns were made with thicknesses of; 0.3 mm, 0.5 mm, 0.7 mm, 1.0 mm, and 1.5 mm; and LDS crowns of 1.0 mm and 1.5 mm thicknesses. Each group consisted of 10 crowns. All crowns underwent artificial aging before loading until fracture. Mean fracture strengths varied from 450 N to 3,248 N in the LTZ group, 438 N to 3,487 N in the HTZ group, and 1,030 N to 1,431 N in the LDS group. The load at fracture of HTZ and LTZ crowns was equal. The load at fracture of yttria-stabilized tetragonal zirconia polycrystals crowns was significantly greater than LDS crowns (P = 0.000). Two types of fractures were recorded; complete and partial crack-like fracture. The crack type fracture occurred most frequently in all groups except in the thicker LTZ groups (1.0 mm and 1.5 mm). According to this study, there is no difference in strength between crowns made of high-translucent or low-translucent zirconia. At equal thickness, the strength of zirconia crowns was significantly greater than that of lithium-disilicate glass-ceramic.

  10. Treatment with double crown-retained removable partial dentures and oral health-related quality of life in middle- and high-aged patients.

    Science.gov (United States)

    Grossmann, Anne-Christiane; Hassel, Alexander J; Schilling, Oliver; Lehmann, Franziska; Koob, Andreas; Rammelsberg, Peter

    2007-01-01

    The objective of this study was to assess the change in oral health-related quality of life following treatment with double crown-retained removable partial dentures (RPDs). Sixty RPDs in 54 patients (mean age: 65 years) were fabricated and retained with either galvanoformed telescopic secondary crowns (n = 30) or conical secondary crowns (n = 30). The Oral Health Impact Profile (OHIP) was assessed pretreatment and during 6- and 12-month follow-up appointments. Patient assessment of denture-satisfaction was also recorded on a Lickert-type scale. A decrease in the OHIP-sum score was significant after treatment for both groups, but not between the experimental groups. The denture assessment showed good values for both groups. Treatment with different double crown-retained RPDs improved oral health-related quality of life.

  11. Crowns and Crypts

    Indian Academy of Sciences (India)

    thesis of stable complexes of all Group-! elements. Crypts form similar but much more stable complexes, also with the alkaline earths. The stabilization ofless familiar oxidation states of a large number of elements using crowns and crypts became an easy task. The basic and the oxidising properties of KOH and KMnO 4'.

  12. Spectrophotometric evaluation of crown fragment a year after ...

    African Journals Online (AJOL)

    Background: Crown fracture is the most common type of fracture and frequently affects the anterior teeth. Crown fractures have been treated in several ways depending on the location and kind of fracture. This case emphasizes reattachment of fractured fragments using fiber-reinforced post. Also this case report underlines ...

  13. Zirconia crowns - the new standard for single-visit dentistry?

    Science.gov (United States)

    Wiedhahn, Klaus; Fritzsche, Günter; Wiedhahn, Claudine; Schenk, Olaf

    2016-01-01

    Zirconia crowns combine the advantages of metal restorations, such as minimally invasive tooth preparation and ease of cementation, with those of full ceramic crowns, such as low thermal conductivity and tooth color. With the introduction of a high-speed sintering procedure, it is possible to produce and cement zirconia crowns and small monolithic bridges in a Cerec Single Visit procedure. This new procedure is compared to established chairside methods.

  14. Multilayered ion-imprinted membranes with high selectivity towards Li+ based on the synergistic effect of 12-crown-4 and polyether sulfone

    Science.gov (United States)

    Lu, Jian; Qin, Yingying; Zhang, Qi; Wu, Yilin; Cui, Jiuyun; Li, Chunxiang; Wang, Liang; Yan, Yongsheng

    2018-01-01

    High-selective multilayered Li+-imprinted membranes (Li-IIMs) with enhanced hydrophilicity and stability were developed based on polyether sulfone substrate membranes. The multilayered structure was prepared with polydopamine (pDA) as the interfacial adhesion layer, SiO2 nanoparticles as the hydrophilic layer and Li+-imprinted polymers as the imprinted layer. The selective ;Li+-recognition sites; were formed using 12-crown-4 (12C4) as the adsorbing units. The optimal relative selectivity coefficients (α) of Li+/Na+ and Li+/K+ reached up to 1.85 and 2.07 with the imprinting factor (β) of 2.51, and the high permselectivity factors (γ) of Na+/Li+ (7.39) and K+/Li+ (9.86) were achieved on Li-IIMs. The Langmuir isotherm model and the pseudo-second-order kinetics model best fitted the rebinding data of Li-IIMs, as well as the rebinding capacities reached up to 90.3% of initial binding after 5 cycles of adsorption/desorption and just declined to 88.1% after another 5 cycles a month later. Therefore, the as-prepared Li-IIMs would have potential applications for the separation of lithium ions from salt lake brines.

  15. Characterization of Microsolvated Crown Ethers from Broadband Rotational Spectroscopy

    Science.gov (United States)

    Perez, Cristobal; Schnell, Melanie; Blanco, Susana; Lopez, Juan Carlos

    2016-06-01

    Since they were first synthetized, crown ethers have been extensively used in organometallic chemistry due to their unparalleled binding selectivity with alkali metal cations. From a structural point of view, crown ethers are heterocycles containing oxygen and/or other heteroatoms, although the most common ones are formed from ethylene oxide unit. Crown ethers are conventionally seen as being hydrophilic inside and hydrophobic outside when the structures found for the metal cation complexes are considered. However, crown ethers are extremely flexible and in isolation may present a variety of stable conformations so that their structure may be easily adapted in presence of a strong ligand as an alkali metal cation minimize the energy of the resulting complex. Water can be considered a soft ligand which interacts with crown ethers through moderate hydrogen bonds. It is thus interesting to investigate which conformers are selected by water to form complexes, the preferred interaction sites and the possible conformational changes due to the presence of one or more water molecules. Previous studies identified microsolvated crown ethers but in all cases with a chromophore group attached to the structure. Here we present a broadband rotational spectroscopy study of microsolvated crown ethers produced in a pulsed molecular jet expansion. Several 1:1 and 1:2 crown ether:water aggregates are presented for 12-crown-4, 15-crown-5 and 18-crown-6. Unambiguous identification of the structures has been achieved using isotopic substitution within the water unit. The subtle changes induced in the structures of the crown ether monomer upon complexation and the hydrogen-bonding network that hold them together will be also discussed. F. Gámez, B. Martínez-Haya, S. Blanco,J. C. López and J. L. Alonso, Phys. Chem. Chem. Phys. 2014, 14 12912-12918 V. A. Shubert, C.W. Müller and T. Zwier, J. Phys. Chem. A 2009, 113 8067-8079

  16. Highly Absorbent Antibacterial Hemostatic Dressing for Healing Severe Hemorrhagic Wounds

    OpenAIRE

    Ting-Ting Li; Ching-Wen Lou; An-Pang Chen; Mong-Chuan Lee; Tsing-Fen Ho; Yueh-Sheng Chen; Jia-Horng Lin

    2016-01-01

    To accelerate healing of severe hemorrhagic wounds, a novel highly absorbent hemostatic dressing composed of a Tencel?/absorbent-cotton/polylactic acid nonwoven base and chitosan/nanosilver antibacterial agent was fabricated by using a nonwoven processing technique and a freeze-drying technique. This study is the first to investigate the wicking and water-absorbing properties of a nonwoven base by measuring the vertical wicking height and water absorption ratio. Moreover, blood agglutination ...

  17. Anaphylactic shock caused by sting of crown-of-thorns starfish (Acanthaster planci).

    Science.gov (United States)

    Ihama, Yoko; Fukasawa, Maki; Ninomiya, Kenji; Kawakami, Yuka; Nagai, Takumi; Fuke, Chiaki; Miyazaki, Tetsuji

    2014-03-01

    A 40s-year-old woman with previous history of injury due to contact with crown-of-thorns starfish, Acanthaster planci, was stung on the right middle finger. After immediately losing consciousness, she died 13 h after injury despite intensive medical treatment. Examination of the respiratory system revealed narrowing due to severe edema of the laryngopharynx, as well as alveolar hemorrhage, eosinophilic infiltration, and extensive neutrophil and eosinophil aggregation in the intravascular lumen of the lungs. Examination of the liver revealed severe diffuse hepatocellular necrosis and extremely high levels of liver transaminases, indicating severe liver damage. Based on these findings, we concluded that she had died from anaphylactic shock induced by circulation of crown-of-thorns starfish venom in the bloodstream. Injurious contact with the spine of the crown-of-thorns starfish can cause severe symptoms as well as systematic reactions, including anaphylaxis. To our knowledge, this is the first case of anaphylactic shock or death caused by human contact with the crown-of-thorns starfish reported in the English-language literature. Although rare, anaphylaxis due to injury by marine animals is potentially fatal. Saving lives requires providing education regarding prevention and enabling prompt response to possible anaphylaxis, including preparation of adrenaline for auto-injection. Copyright © 2014. Published by Elsevier Ireland Ltd.

  18. Estudo de diversas variedades de copas sobre diferentes porta-enxertos da mangueira (Mangifera indica L. Study of several varieties of tree crowns on different rootstocks of mango (Mangifera indica L.

    Directory of Open Access Journals (Sweden)

    S. Simão

    1994-12-01

    Full Text Available O objetivo deste trabalho foi verificar a interferência copa x porta-enxerto no desenvolvimento da mangueira. As alturas e os diâmetros das copas foram tomadas uma vez em 1981, quando as 210 plantas atingiram 15 anos de idade. As variedades de copas estudadas foram as seguintes: Extrema, Oliveira Neto, Carlota, Imperial, Pahiri e Bourbon. Os porta-enxertos utilizados foram Espada, Extrema, Olivara Neto, Carlota, Coco, Pahiri e Bourbon. Os dados foram analisados e a comparação das médias foi feita através do teste de Tukey em nível de 5% de probabilidade. O estudo mostrou que as variedades de copa, Olivara Neto, Extrema e Bourbon atingiram uma altura e um diâmetro maior que as demais variedades.The aim of this paper was to investigate the influence of the combination tree crown + rootstock on mango tree performance. The trees were selected according to height and crown diameter, measured once in 1981, using 210 trees, 15 years old at the beginning of the experiment. The Extrema, Espada, Oliveira Neto, Carlota, Bourbon, Coco and Pahiri varieties were used as rootstock and Extrema, Pahiri, Imperial, Oliveira Neto, Cariota e Bourbon were utilized as scions for tree crown development. Data were analysed by classical statistics, comparing means through the Tukey test, at a probability level of 5%. The crowns Oliveira Neto, Extrema e Bourbon showed the highest heights and diametres.

  19. Marginal adaptation of stainless steel crowns.

    Science.gov (United States)

    Croll, Theodore P; Epstein, David W; Castaldi, Cosmo R

    2003-01-01

    The chief goal of full coronal restoration using preformed stainless steel crowns (SSC) is replication of normal crown form and function. Marginal adaptation of SSCs involves appropriate crown size selection, trimming the crown form to achieve proper length, crimping crown edges to proximate the prepared tooth, and finishing and polishing the crown form. This report about SSC restoration focuses on the procedure of adapting, finishing, and polishing crown margins.

  20. Pulpotomy to stainless steel crown ratio in children with early childhood caries: a cross-sectional analysis.

    Science.gov (United States)

    Thikkurissy, Sarat; McTigue, Dennis; Matracia, Sophie; Casamassimo, Paul

    2011-01-01

    This study's purpose was to determine the pulpotomy-to-crown ratio (PCR) in a high-early childhood caries patient population and factors associated with choice of pulpotomy and crown treatments. This was a retrospective quality assurance chart review. Five calibrated examiners (kappa=0.86) rated radiographic caries from available films. Demographic data, including age, health status, medications, and pain score, were collected along with pulpotomy- and crown-related treatment characteristics of location of tooth, treatment site, and level of operator skill. The record review of 521 patients (mean age=5.1 ± 1.9 years old) revealed 1,365 stainless steel crowns (SSCs) performed with 461 pulpotomies in a 6-month period, in both operating rooms (1,043 SSCs) and ambulatory settings (322 SSCs). The mean PCR was 0.34, with PCR decreasing with increasing patient age. Pulpotomy and crown treatments increased with radiographic caries severity with a significant association between pulpotomy and radiographic severity (Pcrown ratio in this high-early childhood caries pediatric population was 0.34. Pain, the American Society of Anesthesiologists classification system, and radiographic caries severity were predictors of pulpotomy, but operator type and location of treatment were not.

  1. Silica based click-dibenzo-18-crown-6-ether high performance liquid chromatography stationary phase and its application in separation of fullerenes.

    Science.gov (United States)

    Li, Yanzhe; Sheng, Zhe; Zhu, Chuanlei; Yin, Wei; Chu, Changhu

    2018-02-01

    Crown ether is a type of typical macrocyclic polyether compounds, which can produce strong interactions with cationic species, such as metal ions and protonated amines due to its cavity structure and the strong electronegative effect of heteroatoms on the crown ether ring. In this paper, a type of silica based crown ether stationary phase was prepared by covalently bonding dibenzo-18-crown 6-ether (DBCE) on silica gel via copper (I) catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC). The tetraazido DBCE was rapidly prepared by bromomethylation and subsequent azido substitution of DBCE. Finally, this key intermediate was covalently bonded to silica beads by click chemistry to get click-DBCE. Its structure was confirmed by FT-IR and elemental analysis, and the structures of all related intermediates were confirmed by NMR, IR and MS spectra. The crown ether based stationary phase showed good chromatography characteristics and column efficiency (up to 43,553 plates m -1 theoretical plate number is obtained in the case of fluoranthene) under reverse phase liquid chromatographic (RPLC) model. The primary chromatographic evaluation showed that click-DBCE displayed better chromatography efficiency than commercial C18 stationary phase (THERMO BDS HYPERSIL), when they were applied in the separation of regio-isomers of benzene, polycyclic aromatic hydrocarbons (PAHs) and macrolide pharmaceuticals. Furthermore, this stationary phase could also be used to separate fullerenes under normal phase mode, and in this case, 1-chloronaphthalene was suitable additive for improving chromatographic separation ability. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Fracture resistance and failure modes of CEREC endo-crowns and conventional post and core-supported CEREC crowns

    Directory of Open Access Journals (Sweden)

    Chia-Yu Chang

    2009-09-01

    Conclusion: The bonded ceramic endo-crowns showed a significantly higher fracture resistance than the classic reinforced and designed group and, therefore, offer a feasible alternative for severely damaged teeth.

  3. Highly Absorbent Antibacterial Hemostatic Dressing for Healing Severe Hemorrhagic Wounds

    Directory of Open Access Journals (Sweden)

    Ting-Ting Li

    2016-09-01

    Full Text Available To accelerate healing of severe hemorrhagic wounds, a novel highly absorbent hemostatic dressing composed of a Tencel®/absorbent-cotton/polylactic acid nonwoven base and chitosan/nanosilver antibacterial agent was fabricated by using a nonwoven processing technique and a freeze-drying technique. This study is the first to investigate the wicking and water-absorbing properties of a nonwoven base by measuring the vertical wicking height and water absorption ratio. Moreover, blood agglutination and hemostatic second tests were conducted to evaluate the hemostatic performance of the resultant wound dressing. The blending ratio of fibers, areal weight, punching density, and fiber orientation, all significantly influenced the vertical moisture wicking property. However, only the first two parameters markedly affected the water absorption ratio. After the nonwoven base absorbed blood, scanning electron microscope (SEM observation showed that erythrocytes were trapped between the fibrin/clot network and nonwoven fibers when coagulation pathways were activated. Prothrombin time (PT and activated partial thromboplastin time (APTT blood agglutination of the resultant dressing decreased to 14.34 and 50.94 s, respectively. In the femoral artery of the rate bleeding model, hemostatic time was saved by 87.2% compared with that of cotton cloth. Therefore, the resultant antibacterial wound dressing demonstrated greater water and blood absorption, as well as hemostatic performance, than the commercially available cotton cloth, especially for healing severe hemorrhagic wounds.

  4. Development of ultrasonic high temperature system for severe accidents research

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Kil Mo; Kang, Kyung Ho; Kim, Young Ro and others

    2000-07-01

    The aims of this study are to find a gap formation between corium melt and the reactor lower head vessel, to verify the principle of the gap formation and to analyze the effect of the gap formation on the thermal behavior of corium melt and the lower plenum. This report aims at suggesting development of a new high temperature measuring system using an ultrasonic method which overcomes the limitations of the present thermocouple method used for severe accident experiments. Also, this report describes the design and manufacturing method of the ultrasonic system. At that time, the sensor element is fabricated to a reflective element using 1mm diameter and 50 mm and 80 mm long tungsten alloy wires. This temperature measuring system is intended to measure up to 2800 deg C.

  5. Experimental modeling of crown fire initiation in open and closed shrubland systems

    Science.gov (United States)

    W. Tachajapong; S. Lozano; S. Mahalingam; D.R. Weise

    2014-01-01

    The transition of surface fire to live shrub crown fuels was studied through a simplified laboratory experiment using an open-topped wind tunnel. Respective surface and crown fuels used were excelsior (shredded Populus tremuloides wood) and live chamise (Adenostoma fasciculatum, including branches and foliage). A high crown fuel...

  6. Three different surgical techniques of crown lengthening: A comparative study

    Directory of Open Access Journals (Sweden)

    Ramya Nethravathy

    2013-01-01

    Full Text Available Introduction: A short clinical crown may lead to poor retention form thereby leading to improper tooth preparation. Surgical crown lengthening procedure is done to increase the clinical crown length without violating the biologic width. Several techniques have been proposed for clinical crown lengthening which includes gingivectomy, apically displaced flap with or without resective osseous surgery, and surgical extrusion using periotome. Objective: The aim of this paper is to compare clinically the three different surgical techniques of crown lengthening procedures. Materials and Methods: Fifteen patients who reported to the department of Periodontology, were included in the study. Patients were randomly divided into three groups, which include patients who underwent gingivectomy (Group A, apically repositioned flap (Group B and surgical extrusion using periotome (Group C. Clinical measurements such as clinical crown length, gingival zenith, interdental papilla height were taken at baseline and at 3 rd month post-operatively. Results: Clinical and radiographic evaluation at 3 rd month suggest that surgical extrusion technique offers several advantages over the other conventional surgical techniques such as preservation of the interproximal papilla, gingival margin position and no marginal bone loss. Conclusions: This technique can be used to successfully treat a grossly damaged crown structure as a result of tooth fracture, dental caries and iatrogenic factors especially in the anterior region, where esthetics is of great concern.

  7. Ready to crown

    LENUS (Irish Health Repository)

    McReynolds, David

    2017-04-01

    When multiple teeth or localised segments of the mouth require crowns, the restorative interventions involved can be psychologically and physically demanding for the operator, patient and dental technician alike.1,2 It is important that all parties involved in restorations of this nature hold a shared understanding of the expected outcome of treatment, with a realistic, common end goal in mind right from the very beginning. Such clarity of thought and communication is key to avoiding biological, mechanical and aesthetic failures in the planning and execution of advanced restorative treatments. Biomechanically stable and aesthetically pleasing provisional restorations are an essential aspect of treatment, which allow teeth to be prepared and provisionalised over multiple appointments within the comfort zone of the operator and patient.3

  8. Clinical performance of esthetic posterior crowns in primary molars: a pilot study.

    Science.gov (United States)

    Fuks, A B; Ram, D; Eidelman, E

    1999-01-01

    The aim of this pilot study was to assess the clinical performance of esthetic crowns and to compare these to conventional stainless steel crowns (SSC). Twenty two crowns (11 conventional and 11 esthetic) were placed in mandibular primary molars obeying the following criteria: the tooth was not mobile; no fistulae were present; the tooth had at least one caries free or properly restored antagonist and had to be in contact with one adjacent tooth mesially, in the case of the primary second molars or distally in the case of the primary first molars. Crown preparation was done in a conventional manner, but reduction was more extensive for the thicker esthetic crowns, to allow for proper occlusion. The crowns were evaluated clinically and radiographically after 6 months and the following parameters were assessed: gingival health, marginal extension, crown adequacy, proper position or occlusion, proximal contact, chipping of the facing (for esthetic crowns) and cement removal. At the 6 month evaluation all esthetic crowns were intact, without chipping of the facing, and no excess of cement was observed in both groups. No difference was found for marginal extension, occlusion, proximal contact, crown adequacy, and bone resorption, but a significant difference was found for periodontal health between esthetic crowns and conventional SSC (P crowns assessed had several inconveniences, as they resulted in poor gingival health, are very expensive, and, although not measured, are bulky and without a natural appearance.

  9. Precision of fit: the Procera AllCeram crown.

    Science.gov (United States)

    May, K B; Russell, M M; Razzoog, M E; Lang, B R

    1998-10-01

    Strength, color stability, and precision of fit are requirements for all-ceramic restorations. The Procera AllCeram crown system, composed of a densely sintered high-purity alumina core combined with a low fusing surface porcelain, appears to satisfy most of these requirements. However, evaluation of marginal fit has not been reported. This study measured the precision of fit of the Procera AllCeram crown fabricated with Procera CAD/CAM technology for the premolar and molar teeth fit to a die. Five ivorine maxillary first premolars and first molars were prepared for full-coverage crowns. Preparations were standardized with a convergence angle of 10 degrees, chamfer margins of 1.3 to 1.5 mm circumferentially, and occlusal reduction of 2.0 mm. AllCeram crowns were fabricated for the dies, and the fit of the crown to the die was determined by using a standardized procedure with a silicone impression material that served a dual role: (1) as a retrievable luting agent, and (2) to replicate the internal aspects of the crown. Laser videography was used to measure the gap dimension between the crowns and the dies at the marginal opening, the axial wall, the cusp tip, and the occlusal adaptation measurement locations. Mean gap dimensions and standard deviations (SDs) were calculated for marginal opening, internal adaptation, and precision of fit. Mean gap dimensions and standard deviations at the marginal opening for the premolar and molar crowns were 56.0 microns SD +/- 21 and 63.0 microns SD +/- 13 microns, respectively. The mean gap dimensions and SDs of the internal adaptation were 69.0 microns SD +/- 17 microns for axial wall, 48.0 microns SD +/- 12 microns for cusp tip, and 36.0 microns SD +/- 7 microns for occlusal adaptation for the premolar crowns; and 49.0 microns SD +/- 3 microns axial wall, 67.0 microns SD +/- 21 microns cusp tip, and 74.0 microns SD +/- 29 microns occlusal adaptation for molar crowns. Precision of fit and SDs for premolar and molar crowns were

  10. Aesthetic preformed crowns for primary teeth.

    Science.gov (United States)

    Taylor, Greig D

    2017-06-23

    Data sourcesMedline, Cochrane central register of controlled trials, US National Institutes of Health Trials Register and the World Health Organization International Clinical Trials Registry Platform.Study selectionEnglish language randomised clinical trials comparing APCs with conventional restorative techniques for primary teeth.Data extraction and synthesisStudy selection and data abstraction were conducted independently by two reviewers. Risk of bias was assessed using the Cochrane risk of bias tool. Study characteristics and results were described qualitatively. Meta-analysis was not conducted.ResultsSeven studies were included, six reported on primary molars and one on primary incisors. There was great variety in the design of the RCTs, however, all compared pre-veneered stainless steel crowns (SSCs) with other crowns or two different pre-veneered SSCs. The risk of bias in all studies was high with significantly different outcome measures used.ConclusionsSSCs cannot be replaced by APCs for restoring decayed primary molar teeth due to the insufficient quality of evidence available. After a follow-up of only six months, zircon crowns gave significantly better results than the others regarding gingival health and crown fractures. Due to the small number of RCTs on this topic and their risk of bias, future RCTs should be carried out in primary teeth.

  11. Preformed posterior stainless steel crowns: an update.

    Science.gov (United States)

    Croll, T P

    1999-02-01

    For almost 50 years, dentists have used stainless steel crowns for primary and permanent posterior teeth. No other type of restoration offers the convenience, low cost, durability, and reliability of such crowns when interim full-coronal coverage is required. Preformed stainless steel crowns have improved over the years. Better luting cements have been developed and different methods of crown manipulation have evolved. This article reviews stainless steel crown procedures for primary and permanent posterior teeth. Step-by-step placement of a primary molar stainless steel crown is documented and permanent molar stainless steel crown restoration is described. A method for repairing a worn-through crown also is reviewed.

  12. In Vitro Shock Absorption Tests on Implant-Supported Crowns: Influence of Crown Materials and Luting Agents.

    Science.gov (United States)

    Rosentritt, Martin; Schneider-Feyrer, Sibylle; Behr, Michael; Preis, Verena

    2017-05-18

    To investigate the force absorption capacity of implant-supported crowns made of different restorative materials and connected to abutments with different luting agents. Molar crowns were milled of different computer-aided design/computer-aided manufacture materials (n = 8 crowns per material): polymethyl methacrylate, polyether ether ketone, composite, lithium disilicate, titanium, and zirconia. Crowns were mounted on titanium implant replicas using different luting agents: uncemented, temporarily cemented (zinc oxide-eugenol cement), conventionally cemented (zinc oxide phosphate cement), and adhesively bonded. As a reference, one implant replica was tested without a crown. Force absorptions of the different combinations of crown materials and luting agents were determined by applying an increasing force (0 to 250 N) on the occlusal crown surface and measuring the resulting force below the implant. Mean curves of applied and resulting forces up to 200 N were determined (six measurements per group), and slopes were calculated. Statistical analysis was performed (one-way analysis of variance, Bonferroni post hoc test, α = .05). Significant (P crown materials that were uncemented, temporarily cemented, cemented, and adhesively bonded. Materials with higher moduli of elasticity (ceramics, titanium) showed steeper slopes of the force curves and lower shock-absorbing capacity than resin-based materials, but were influenced more by the luting agents. The damping effects of resin-based materials were higher in combination with all cementation and luting modes. Shock absorption tests exhibited a strong material-dependent damping behavior of implant-supported crowns. The shock-absorbing capacity of crown materials with high moduli of elasticity may benefit from conventional cementation.

  13. The diagnosis of severe thunderstorms with high-resolution WRF ...

    Indian Academy of Sciences (India)

    impact of three microphysical schemes in cap- turing the severe thunderstorm event occurred over Kolkata on 15 May 2009. Also, we have made an attempt to .... species (water vapour, cloud water, rainwater, ice, snow and graupel) (Otkin and Greenwald. 2008). Sensitivity experiments have been con- ducted for a severe ...

  14. High cardiovascular risk in severely obese young children and adolescents

    NARCIS (Netherlands)

    Emmerik, N.M.A. van; Renders, C.M.; Veer, M. van de; Buuren, S. van; Baan-Slootweg, O.H. van der; Kist-van Holthe, J.E.; HiraSing, R.A.

    2012-01-01

    Objective: To assess the prevalence of cardiovascular risk factors in severely obese children and adolescents. Methods: A nationwide prospective surveillance study was carried out from July 2005 to July 2007 where paediatricians were asked to report all new cases of severe obesity in 2-18-year-old

  15. Silica crown refractory corrosion in glass melting furnaces

    Directory of Open Access Journals (Sweden)

    Balandis A.

    2011-01-01

    Full Text Available The critical parameters of silica refractories, such as compressive strength, bulk, density, quantity of silica, microstructure and porosity were evaluated of unused and used bricks to line the crowns of glass furnaces, when the rate of corrosion of crowns were about 2 times greater. The change of these parameters, the chemical composition and formation of the microcracks in the used silica refractories material were studied. It was established that the short time at service of container glass furnace crown can be related to low quality of silica brick: high quantity of CaO and impurities, low quantity of silica, low quantity of silica, transferred to tridymite and cristobalite and formation of 5-10 μm and more than 100 μm cracks in the crown material. The main reason of corrosion high quality silica bricks used to line the crown of electrovacuum glass furnace is the multiple cyclic change of crown temperature at 1405 - 1430°C range in the initial zone of crown and at 1575 - 1605°C range in the zone of highest temperatures.

  16. The Effects of Margin Curvature on Load at Fracture of Ceramic Crowns.

    Science.gov (United States)

    Øilo, Marit; Kvam, Ketil; Reisegg, Kjetil; Gjerdet, Nils Roar

    2015-01-01

    Despite the high fracture strength of modern dental core ceramics, fractures are a common cause of clinical failures. The aim of this study was to use a clinically relevant test method to evaluate the effect of the curvature of the cervical crown margins on load at fracture. Thirty zirconia crowns and 30 glass-ceramic crowns were produced for three premolar preparations with variation in the approximal crown margin curvature: low curvature (r=12 mm), moderate curvature (r=2.5 mm), and high curvature (r=1.5). The crowns were loaded until fracture with a method that mimics clinical fracture modes. Statistically significant differences were found among both crown margin curvature and material groups (Pcrown margins increases crown strength compared with a high curvature.

  17. An automatic robotic system for three-dimensional tooth crown preparation using a picosecond laser.

    Science.gov (United States)

    Wang, Lei; Wang, Dangxiao; Zhang, Yuru; Ma, Lei; Sun, Yuchun; Lv, Peijun

    2014-09-01

    Laser techniques have been introduced into dentistry to overcome the drawbacks of traditional treatment methods. The existing methods in dental clinical operations for tooth crown preparation have several drawbacks which affect the long-term success of the dental treatment. To develop an improved robotic system to manipulate the laser beam to achieve safe and accurate three-dimensional (3D) tooth ablation, and thus to realize automatic tooth crown preparation in clinical operations. We present an automatic laser ablation system for tooth crown preparation in dental restorative operations. The system, combining robotics and laser technology, is developed to control the laser focus in three-dimensional motion aiming for high speed and accuracy crown preparation. The system consists of an end-effector, a real-time monitor and a tooth fixture. A layer-by-layer ablation method is developed to control the laser focus during the crown preparation. Experiments are carried out with picosecond laser on wax resin and teeth. The accuracy of the system is satisfying, achieving the average linear errors of 0.06 mm for wax resin and 0.05 mm for dentin. The angle errors are 4.33° for wax resin and 0.5° for dentin. The depth errors for wax resin and dentin are both within 0.1 mm. The ablation time is 1.5 hours for wax resin and 3.5 hours for dentin. The ablation experimental results show that the movement range and the resolution of the robotic system can meet the requirements of typical dental operations for tooth crown preparation. Also, the errors of tooth shape and preparation angle are able to satisfy the requirements of clinical crown preparation. Although the experimental results illustrate the potential of using picosecond lasers for 3D tooth crown preparation, many research issues still need to be studied before the system can be applied to clinical operations. © 2014 Wiley Periodicals, Inc.

  18. The diagnosis of severe thunderstorms with high-resolution WRF ...

    Indian Academy of Sciences (India)

    Gangetic Plain and northeast India is the outburst of severe local convective storms, commonly known as 'Nor'westers'(as they ... Centre for Atmospheric Sciences, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India.

  19. Overdenture dengan Pegangan Telescopic Crown

    Directory of Open Access Journals (Sweden)

    Pambudi Santoso

    2014-06-01

    Full Text Available Kaitan presisi merupakan alat retensi mekanis yang menghubungkan antara satu atau lebih pegangan gigi tiruan, yang bertujuan untuk menambah retensi dan/atau stabilisasi. Kaitan presisi dapat digunakan secara luas pada gigi tiruan cekat, gigi tiruan sebagian lepasan, overdenture, implant untuk retensi overdenture, dan protesa maksilo fasial. Overdenture dengan kaitan presisi dapat membantu dalam pembagian beban kunyah, meminimalkan trauma pada gigi pegangan dan jaringan lunak, meminimalkan resorbsi tulang, dan meningkatkan estetik dan pengucapan suara. Salah satu jenis dari kaitan presisi adalah telescopic crown, terdiri dari 2 macam mahkota, yaitu mahkota primer yang melekat secara permanen pada gigi penyangga, dan mahkota sekunder yang melekat pada gigi tiruan. Tujuan pemaparan kasus ini adalah untuk memberikan informasi tentang rehabilitasi pasien edentulous sebagian rahang atas dengan telescopic crown..  Pasien wanita berusia 45 tahun datang ke klinik prostodonsia RSGM Prof.Soedomo dengan keluhan ingin dibuatkan gigi tiruan. Pasien kehilangan gigi 11 12 15 16 17 21 22 24 25 26 dan 27 yang diindikasikan untuk pembuatan overdenture gigi tiruan sebagian lepasan (GTS kerangka logam dengan pegangan telescopic crown pada gigi 13 dan 14 dengan sistem parallel-sided crown. Tahap-tahap pembuatan telescopic crown yaitu mencetak model study dengan catatan gigit pendahuluan. Perawatan saluran dilakukan pada akar gigi 13, dilanjutkan pemasangan pasak fiber serta rewalling dinding bukal. Gigi 13 dan 14 dilakukan preparasi mahkota penuh, dilanjutkan dengan pencetakan model kerja untuk coping primer dan kerangka logam dengan metode double impression. Coping primer disementasi pada gigi penyangga, dilanjutkan pasang coba coping sekunder beserta kerangka logam. Selanjutnya dilakukan pencatatan gigit, pencetakan model kerja, penyusunan gigi dan pasang coba penyusunan gigi pada pasien. Prosedur dilanjutkan dengan proses di laboratorium, serta insersi pada

  20. Intracranial Pressure during HighVolume Hemofiltration in Severe Sepsis

    Directory of Open Access Journals (Sweden)

    A. P. Berdnikov

    2014-01-01

    Full Text Available Objective: to define the prognostic value of intracranial pressure (ICP changes in highvolume hemofiltration (HVHF in patients with severe sepsis and normal preperfusion ICP.Subjects and methods. A retrospective study was conducted in 50 patients (a total of 134 sessions with severe sepsis and normal baseline ICP who received ther apy using HVHF for extrarenal indications. Based on ICP changes before and after HVHF, the investigators identified 2 groups: 1 no ICP changes (n=81; 2 elevated ICP (n=53.Conclusion. HVHF is ineffective when the normal preperfusion ICP is increased in patients with severe sepsis who have a concurrence of an arteriovenous carbon dioxide difference of more than 8 mm Hg and a Glasgow coma score of less than 10.

  1. A Randomized Controlled Trial of Crown Therapy in Young Individuals with Amelogenesis Imperfecta.

    Science.gov (United States)

    Pousette Lundgren, G; Morling Vestlund, G I; Trulsson, M; Dahllöf, G

    2015-08-01

    Amelogenesis imperfecta (AI) is a rare, genetically determined defect in enamel mineralization. Existing treatment recommendations suggest resin-composite restorations until adulthood, although such restorations have a limited longevity. New crown materials allow for minimal preparation techniques. The aim of this study was to compare the quality and longevity of 2 crown types-Procera and IPS e.max Press-in adolescents and young adults with AI. A secondary aim was to document adverse events. We included 27 patients (11 to 22 y of age) with AI in need of crown therapy in a randomized controlled trial using a split-mouth technique. After placing 119 Procera crowns and 108 IPS e.max Press crowns following randomization, we recorded longevity, quality, adverse events, and tooth sensitivity. After 2 y, 97% of the crowns in both crown groups had excellent or acceptable quality. We found no significant differences in quality between Procera and IPS e.max Press crowns. Tooth sensitivity was significantly reduced after crown therapy (P crowns. The results show that it is possible to perform crown therapy with excellent results and without severe complications in young patients with AI. The study is registered at http://www.controlled-trials.com (ISRCTN70438627). © International & American Associations for Dental Research 2015.

  2. Clinical assessment of enamel wear caused by monolithic zirconia crowns.

    Science.gov (United States)

    Stober, T; Bermejo, J L; Schwindling, F S; Schmitter, M

    2016-08-01

    The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6-, 12-, and 24-month follow-up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser-scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two-sided paired Student's t-tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19-26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75-115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia-opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified. © 2016 John Wiley & Sons Ltd.

  3. Spectrum of choices to restore the smile of a child: An update on current pediatric anterior crowns

    Directory of Open Access Journals (Sweden)

    Amit Kumar Sahu

    2016-01-01

    Full Text Available Esthetic treatment of severely damaged primary teeth is one of the greatest challenges to pediatric dentists. A wide variety of full coverage esthetic crowns for primary teeth are commercially available in the market. A practitioner should choose convenient, durable, and reliable solution which is fulfilled with complete knowledge of different crown forms. This article on esthetic crowns for children gives an outline of various anterior crowns in a tabular form, reviews their composition, advantages, disadvantages, and selection criteria.

  4. Research and primary evaluation of an automatic fusion method for multisource tooth crown data.

    Science.gov (United States)

    Dai, Ning; Li, Dawei; Yang, Xu; Cheng, Cheng; Sun, Yuchun

    2017-11-01

    With the development of 3-dimensional (3D) scanning technologies in dentistry, high accuracy optical scanning data from the crown and cone beam computed tomography data from the root can be acquired easily. In many dental fields, especially in digital orthodontics, it is useful to fuse the data from the crown and the root. However, the manual fusion method is complex and difficult. A novel automatic fusion method for 2-source data from the crown and the root was researched, and its accuracy was evaluated in this study. An occlusal splint with several alumina ceramic spheres was fabricated using heat-curing resin. A multipoint (center of each sphere) alignment method was performed to achieve rapid registration of the crown data from optical scanning and the root data from cone beam computed tomography. The segmentation algorithm based on heuristic search was adopted to perform extraction and segmentation of the crown from whole optical scanning data. The level set algorithm and the marching cubes (MC) algorithm were used to reconstruct digital imaging and communications in medicine data into a 3D model. A novel multisource data fusion algorithm, which is based on iterative Laplacian deformation (ILD), was researched and applied to achieve automatic fusion. Finally, the 3D errors of the method were evaluated. The 3 groups of typical tooth data were automatically fused within 2 seconds. The mean standard deviation was less than 0.02 mm. The novel method can aid the construction of a high-quality 3D model of complete teeth to enable orthodontists to safely, reliably, and visually plan tooth alignment programs. Copyright © 2017 John Wiley & Sons, Ltd.

  5. Grapevine (Vitis vinifera) Crown Galls Host Distinct Microbiota.

    Science.gov (United States)

    Faist, Hanna; Keller, Alexander; Hentschel, Ute; Deeken, Rosalia

    2016-09-15

    Crown gall disease of grapevine is caused by virulent Agrobacterium strains and establishes a suitable habitat for agrobacteria and, potentially, other bacteria. The microbial community associated with grapevine plants has not been investigated with respect to this disease, which frequently results in monetary losses. This study compares the endophytic microbiota of organs from grapevine plants with or without crown gall disease and the surrounding vineyard soil over the growing seasons of 1 year. Amplicon-based community profiling revealed that the dominating factor causing differences between the grapevine microbiota is the sample site, not the crown gall disease. The soil showed the highest microbial diversity, which decreased with the distance from the soil over the root and the graft union of the trunk to the cane. Only the graft union microbiota was significantly affected by crown gall disease. The bacterial community of graft unions without a crown gall hosted transient microbiota, with the three most abundant bacterial species changing from season to season. In contrast, graft unions with a crown gall had a higher species richness, which in every season was dominated by the same three bacteria (Pseudomonas sp., Enterobacteriaceae sp., and Agrobacterium vitis). For in vitro-cultivated grapevine plantlets, A. vitis infection alone was sufficient to cause crown gall disease. Our data show that microbiota in crown galls is more stable over time than microbiota in healthy graft unions and that the microbial community is not essential for crown gall disease outbreak. The characterization of bacterial populations in animal and human diseases using high-throughput deep-sequencing technologies, such as 16S amplicon sequencing, will ideally result in the identification of disease-specific microbiota. We analyzed the microbiota of the crown gall disease of grapevine, which is caused by infection with the bacterial pathogen Agrobacterium vitis. All other Agrobacterium

  6. Canopy Fuel Load Mapping of Mediterranean Pine Sites Based on Individual Tree-Crown Delineation

    Directory of Open Access Journals (Sweden)

    Giorgos Mallinis

    2013-12-01

    Full Text Available This study presents an individual tree-crown-based approach for canopy fuel load estimation and mapping in two Mediterranean pine stands. Based on destructive sampling, an allometric equation was developed for the estimation of crown fuel weight considering only pine crown width, a tree characteristic that can be estimated from passive imagery. Two high resolution images were used originally for discriminating Aleppo and Calabrian pines crown regions through a geographic object based image analysis approach. Subsequently, the crown region images were segmented using a watershed segmentation algorithm and crown width was extracted. The overall accuracy of the tree crown isolation expressed through a perfect match between the reference and the delineated crowns was 34.00% for the Kassandra site and 48.11% for the Thessaloniki site, while the coefficient of determination between the ground measured and the satellite extracted crown width was 0.5. Canopy fuel load values estimated in the current study presented mean values from 1.29 ± 0.6 to 1.65 ± 0.7 kg/m2 similar to other conifers worldwide. Despite the modest accuracies attained in this first study of individual tree crown fuel load mapping, the combination of the allometric equations with satellite-based extracted crown width information, can contribute to the spatially explicit mapping of canopy fuel load in Mediterranean areas. These maps can be used among others in fire behavior prediction, in fuel reduction treatments prioritization and during active fire suppression.

  7. Clinical evaluation of and parental satisfaction with resin-faced stainless steel crowns.

    Science.gov (United States)

    Roberts, C; Lee, J Y; Wright, J T

    2001-01-01

    This study evaluated the clinical success and parental acceptance of anterior primary dentition caries treatment with prefabricated resin-faced stainless steel crowns. A retrospective analysis of maxillary anterior primary dentition caries treatment using Whiter Biter II Crowns was performed. Each crown was evaluated for retention, fracture, interface failure, color match, marginal integrity, and surface texture. Parental satisfaction regarding the esthetics of the crowns was evaluated by survey. Thirty-eight crowns were evaluated in 12 children. The average crown age at time of examination was 20.7 months. Three teeth were lost to trauma with all other crowns remaining intact. Twelve crowns (32%) showed loss of at least some facial resin. Nine crowns (24%) had complete loss of the resin facing. Overall parental satisfaction with the treatment was excellent, however, satisfaction with crown esthetics received the lowest rating. While parental satisfaction with treatment of anterior primary dentition caries with prefabricated resin-faced stainless steel crowns is excellent, the high failure rate of the resin facings is problematic.

  8. Track prediction of very severe cyclone 'Nargis' using high resolution ...

    Indian Academy of Sciences (India)

    In the present study, a detailed diagnostic analysis of the system 'Nargis' is carried out initially to investigate the features associated with this unusual movement and subsequently the real time forecast of VSCS 'Nargis' using high resolution advanced version weather research forecasting (WRF) model is presented.

  9. High-precision timeline for Earth's most severe extinction.

    Science.gov (United States)

    Burgess, Seth D; Bowring, Samuel; Shen, Shu-zhong

    2014-03-04

    The end-Permian mass extinction was the most severe loss of marine and terrestrial biota in the last 542 My. Understanding its cause and the controls on extinction/recovery dynamics depends on an accurate and precise age model. U-Pb zircon dates for five volcanic ash beds from the Global Stratotype Section and Point for the Permian-Triassic boundary at Meishan, China, define an age model for the extinction and allow exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Mya, an interval of 60 ± 48 ka. Onset of a major reorganization of the carbon cycle immediately precedes the initiation of extinction and is punctuated by a sharp (3‰), short-lived negative spike in the isotopic composition of carbonate carbon. Carbon cycle volatility persists for ∼500 ka before a return to near preextinction values. Decamillenial to millennial level resolution of the mass extinction and its aftermath will permit a refined evaluation of the relative roles of rate-dependent processes contributing to the extinction, allowing insight into postextinction ecosystem expansion, and establish an accurate time point for evaluating the plausibility of trigger and kill mechanisms.

  10. [Fracture toughness of zirconia ceramic crowns made by feather-edge tooth preparation design].

    Science.gov (United States)

    Mirković, Nemanja; Gostović, Aleksandra Spadijer; Lazić, Zoran; Trifković, Branka

    2012-07-01

    Fracture toughness determines functional crown strenght and prevents damages on ceramics during mastication. There is a lack of relevant literature data about fracture toughness of crowns made by feather-edge preparation. Mechanical testing of ceramic samples is supposed to show if feather-edge tooth preparation is a successful method for making ceramic crowns without any risk of reduction of their mechanical properties. This research was done to establish effects of feather-edge tooth preparation on fracture toughness of single zirconia ceramic crowns. The research was performed as an experimental study. Sixty (60) ceramic crowns were made on non-carious extracted human premolars. Thirty (30) crowns were made on the basis of feather-edge preparation (experimental group I). The group II included 30 crowns made on 1 mm rounded shoulder. Crowns fabrication was executed on a copy mill production system "Zirkonzahn" (Zirkonzahn GMBH, Gais, Germany). The spherical compression test was used to determine fracture toughness, using 6 mmn diameter ceramic ball. Fracture load for damaging ceramic crown was recorded on a universal testing machine--Zwick, type 1464, with the speed of 0.05 mm/min. The results of this research introduced significant differences between fracture toughness of ceramic samples in every examined group. However, fracture toughness of crowns from both group was above 2000 N, what was double beyond a recommended value. The mean value of fracture toughness in the feather-edge group was 2090 N, and in shoulder group it was 2214 N. This research showed a high fracture toughness of zirconia crowns made on feather-edge preparation. The examined crowns showed a fracture resistance at a sufficient distance in relation to the minimum values of functional loads. Further research of functional loads of these crown is necessary, as well as research of marginal adaptation of cemented crowns and gingival inflammatory response.

  11. Fracture toughness of zirconia ceramic crowns made by feather-edge tooth preparation design

    Directory of Open Access Journals (Sweden)

    Mirković Nemanja

    2012-01-01

    Full Text Available Background/Aim. Fracture toughness determines functional crown strenght and prevents damages on ceramics during mastication. There is a lack of relevant literature data about fracture toughness of crowns made by feather-edge preparation. Mechanical testing of ceramic samples is supposed to show if feather-edge tooth preparation is a successful method for making ceramic crowns without any risk of reduction of their mechanical properties. This research was done to establish effects of feather-edge tooth preparation on fracture toughness of single zirconia ceramic crowns. Methods. The research was performed as an experimental study. Sixty (60 ceramic crowns were made on non-carious extracted human premolars. Thirty (30 crowns were made on the basis of feather-edge preparation (experimental group I. The group II included 30 crowns made on 1 mm rounded shoulder. Crowns fabrication was executed on a copy mill production system “Zirkonzahn” (Zirkonzahn GMBH, Gais, Germany. The spherical compression test was used to determine fracture toughness, using 6 mm diameter ceramic ball. Fracture load for damaging ceramic crown was recorded on a universal testing machine - Zwick, type 1464, with the speed of 0.05 mm/min. Results. The results of this research introduced significant differences between fracture toughness of ceramic samples in every examined group. However, fracture toughness of crowns from both group was above 2 000 N, what was double beyond a recommended value. The mean value of fracture toughness in the feather-edge group was 2 090 N, and in shoulder group it was 2 214 N. Conclusion. This research showed a high fracture toughness of zirconia crowns made on feather-edge preparation. The examined crowns showed a fracture resistance at a sufficient distance in relation to the minimum values of functional loads. Further research of functional loads of these crown is necessary, as well as research of marginal adaptation of cemented crowns and

  12. Wave Forces on Crown Walls

    DEFF Research Database (Denmark)

    Pedersen, Jan; Burcharth, H. F.

    1993-01-01

    This paper presents some of the results from a large parametric laboratory study including more than 200 long-duration model tests. The study addresses both the wave forces imposed on the breakwater crown wall as well as the performance of the structure in reducing the wave overtopping. The testing...... programme includes variations of the sea state parameters and of the geometrical configuration of the breakwater and crown wall. Basic relations between forces/overtopping and the varied parameters are examined and preliminary design guidelines for structures within the tested range of variations...

  13. Computational assessment of several hydrogen-free high energy compounds.

    Science.gov (United States)

    Tan, Bisheng; Huang, Ming; Long, Xinping; Li, Jinshan; Fan, Guijuan

    2016-01-01

    Tetrazino-tetrazine-tetraoxide (TTTO) is an attractive high energy compound, but unfortunately, it is not yet experimentally synthesized so far. Isomerization of TTTO leads to its five isomers, bond-separation energies were empolyed to compare the global stability of six compounds, it is found that isomer 1 has the highest bond-separation energy (1204.6kJ/mol), compared with TTTO (1151.2kJ/mol); thermodynamic properties of six compounds were theoretically calculated, including standard formation enthalpies (solid and gaseous), standard fusion enthalpies, standard vaporation enthalpies, standard sublimation enthalpies, lattice energies and normal melting points, normal boiling points; their detonation performances were also computed, including detonation heat (Q, cal/g), detonation velocity (D, km/s), detonation pressure (P, GPa) and impact sensitivity (h50, cm), compared with TTTO (Q=1311.01J/g, D=9.228km/s, P=40.556GPa, h50=12.7cm), isomer 5 exhibites better detonation performances (Q=1523.74J/g, D=9.389km/s, P=41.329GPa, h50= 28.4cm). Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Retention of Resin Composite CAM Crowns Following Different Bonding Protocols

    Science.gov (United States)

    Nejat, Amir Hossein

    Objectives: Resin composite CAM materials offer more efficient milling, however, there is a high incidence of clinical debonding when this material is used for full-coverage crowns. The aim of the present study is to evaluate the effect of different surface treat-ments and primers on the crown retention of a new resin composite CAM material. Methods: 120 molars were prepared with a 24 degree taper, 1.5mm height, and axial walls in dentin. Surface area was measured by digital microscopy and preparations were scanned with an intraoral scanner. Crowns were milled from an experimental com-posite material with 4mm occlusal height. Teeth were randomly allocated to 12 groups (n= 10) based on the possible combinations of three surface treatments (Control, Alumina air abrasion [50mum Al2O3 at 0.28MPa], Hydrofluoric acid etch [5% HF acid for 20 sec]), silane application (with or without Kerr Silane), and adhesive application (with or without Optibond XTR adhesive). Optibond XTR adhesive was applied to the tooth preparations and crowns were bonded with MaxCem Elite. Crowns were fatigued for 100,000 cycles at 100N in water. Crowns were debonded in tension in a universal testing machine at 1mm/min. Crown retention strength (maximum load/area of preparation) was analyzed using a three-way ANOVA with Tukey's post-hoc tests. Results: Surface treatment, silane and adhesive applications independently affect the retention force (pResin composite crowns should be alumina particle abraded and coated with silane and adhesive.

  15. Double-crown-retained removable dental prostheses: a retrospective study of survival and complications.

    Science.gov (United States)

    Schwindling, Franz Sebastian; Dittmann, Britta; Rammelsberg, Peter

    2014-09-01

    Research data are scarce on double-crown-retained removable dental prostheses. In double-crown-retained removable dental prostheses, crown-like copings are definitively cemented to the abutment teeth and serve as prosthesis attachments. The purpose of this study was to evaluate the survival of double-crown-retained removable dental prostheses in use for 7 years and to determine their most common complications. A retrospective analysis was conducted to investigate the clinical outcome of 117 prostheses in 86 patients with 385 abutment teeth. Thirty-two telescopic-crown-retained removable dental prostheses, 51 conical-crown-retained removable dental prostheses, and 34 resilient telescopic-crown-retained overdentures were clinically reexamined by 1 investigator. Prosthesis success was defined as survival without severe complications (abutment tooth extraction). Statistical analyses were performed with Kaplan-Meier modeling and Cox regression (α=.05). Minor complications, for example, the decementation of primary crowns (34.2%), failure of the veneer of secondary crowns (11.1%), fracture of the denture base (17.1%), and the need for relining (12%), were common. Cumulative prosthesis survival for all types of prostheses was 93.8% after 7 years. After the same period, prosthesis success was 90% for telescopic-crown-retained removable dental prostheses and 78.5% for conical-crown-retained removable dental prostheses and resilient telescopic-crown-retained overdentures. The medium-term double-crown-retained removable dental prosthesis survival found in this retrospective investigation appears acceptable. When bearing in mind the limits of this study, this kind of prosthesis might be a viable treatment option for patients with a reduced dentition. However, more laboratory and clinical research is necessary to reduce the incidence of minor complications and confirm the present in vivo results in larger patient groups. Copyright © 2014 Editorial Council for the Journal of

  16. Failure modes and fracture origins of porcelain veneers on bilayer dental crowns.

    Science.gov (United States)

    Liu, Yihong; Liu, Guanghua; Wang, Yong; Shen, James Zhijian; Feng, Hailan

    2014-01-01

    The aims of this study were to determine the fracture origins and crack paths in the porcelain of clinically failed bilayer ceramic restorations and to reveal the correlation between the porcelain failures and material properties. Three clinically failed crowns of each material (bilayer zirconia crowns, galvano-ceramic crowns, and porcelain-fused-to-metal crowns) were collected and underwent failure analysis. The fractures found in porcelain veneers showed several characteristics including wear, Hertzian cone crack, chipping off, and delamination. The results indicated that the fracture origins and features of the porcelain in bilayer ceramic restorations might be affected by the rigidity of core materials and thickness of copings.

  17. A Rare Case of Crowned Dens Syndrome Mimicking Aseptic Meningitis

    Directory of Open Access Journals (Sweden)

    Teruyuki Takahashi

    2013-03-01

    Full Text Available Background: Crowned dens syndrome (CDS, related to microcrystalline deposition in the periodontoid process, is the main cause of acute or chronic cervical pain. Microcrystal-line deposition most often consists of calcium pyrophosphate dehydrate crystals and/or hydroxyapatite crystals. Case Presentation: This report describes the case of an 89-year-old woman who presented with sudden onset, high fever, severe occipital headache, and neck stiffness. A laboratory examination revealed a markedly elevated white blood cell count (11,100/µl and C-reactive protein level (23.8 mg/dl. These clinical findings suggested severe infection such as meningitis with sepsis. However, the results of blood culture, serum endotoxin, and procalcitonin were all negative, and cerebrospinal fluid studies revealed only a slight abnormality. The patient was first diagnosed with meningitis and treated with antiviral and antibiotic agents as well as non-steroidal anti-inflammatory drugs, but they only had limited effects. A cervical plain computed tomography (CT scan and its three-dimensional (3D reconstruction detected a remarkable crown-like calcification surrounding the odontoid process. On the basis of the CT findings, the patient was diagnosed as a severe case of CDS and was immediately treated with corticosteroids. The patient's condition drastically improved within a week after one course of corticosteroid therapy. Conclusion: Some atypical symptoms of CDS are misleading and may be misdiagnosed as meningitis, as happened in our case. A CT scan, especially a 3D-CT scan, is necessary and useful for a definitive diagnosis of CDS. CDS should be considered as a differential diagnosis of a possible etiology for fever, headache, and cervical pain of unknown origin.

  18. Earth Pressure on Tunnel Crown

    DEFF Research Database (Denmark)

    Andersen, Lars

    Two different analyses have been carried out in order to find the vertical earth pressure, or overburden pressure, at the crown of a tunnel going through a dike. Firstly, a hand calculation is performed using a simple dispersion of the stresses over depth. Secondly, the finite‐element program...

  19. A conceptual framework for ranking crown fire potential in wildland fuelbeds.

    Science.gov (United States)

    Mark D. Schaaf; David V. Sandberg; Maarten D. Schreuder; Cynthia L. Riccardi

    2007-01-01

    This paper presents a conceptual framework for ranking the crown fire potential of wildland fuelbeds with forest canopies. This approach extends the work by Van Wagner and Rothermel, and introduces several new physical concepts to the modeling of crown fire behavior derived from the reformulated Rothemel surface fire modeling concepts proposed by Sandberg et al. This...

  20. Equations to convert compacted crown ratio to uncompacted crown ratio for trees in the Interior West

    Science.gov (United States)

    Chris Toney; Matthew C. Reeves

    2009-01-01

    Crown ratio is the proportion of total tree length supporting live foliage. Inventory programs of the US Forest Service generally define crown ratio in terms of compacted or uncompacted measurements. Measurement of compacted crown ratio (CCR) involves envisioning the transfer of lower branches of trees with asymmetric crowns to fill holes in the upper portion of the...

  1. Digital photo monitoring for tree crown

    Science.gov (United States)

    Neil Clark; Sang-Mook Lee

    2007-01-01

    Assessing change in the amount of foliage within a tree’s crown is the goal of crown transparency estimation, a component in many forest health assessment programs. Many sources of variability limit analysis and interpretation of crown condition data. Increased precision is needed to detect more subtle changes that are important for detection of health problems....

  2. 21 CFR 872.3330 - Preformed crown.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Preformed crown. 872.3330 Section 872.3330 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3330 Preformed crown. (a) Identification. A preformed crown is a prefabricated device made of plastic or austenitic alloys or alloys containing 75 percent or...

  3. Antibacterial activity of plant defensins against alfalfa crown rot pathogens

    Science.gov (United States)

    Alfalfa (Medicago sativa) is the fourth most widely grown crop in the United States. Alfalfa crown rot is a disease complex that severely decreases alfalfa stand density and productivity in all alfalfa-producing areas. Currently, there are no viable methods of disease control. Plant defensins are sm...

  4. DNA methylation mediated control of gene expression is critical for development of crown gall tumors.

    Directory of Open Access Journals (Sweden)

    Jochen Gohlke

    Full Text Available Crown gall tumors develop after integration of the T-DNA of virulent Agrobacterium tumefaciens strains into the plant genome. Expression of the T-DNA-encoded oncogenes triggers proliferation and differentiation of transformed plant cells. Crown gall development is known to be accompanied by global changes in transcription, metabolite levels, and physiological processes. High levels of abscisic acid (ABA in crown galls regulate expression of drought stress responsive genes and mediate drought stress acclimation, which is essential for wild-type-like tumor growth. An impact of epigenetic processes such as DNA methylation on crown gall development has been suggested; however, it has not yet been investigated comprehensively. In this study, the methylation pattern of Arabidopsis thaliana crown galls was analyzed on a genome-wide scale as well as at the single gene level. Bisulfite sequencing analysis revealed that the oncogenes Ipt, IaaH, and IaaM were unmethylated in crown galls. Nevertheless, the oncogenes were susceptible to siRNA-mediated methylation, which inhibited their expression and subsequently crown gall growth. Genome arrays, hybridized with methylated DNA obtained by immunoprecipitation, revealed a globally hypermethylated crown gall genome, while promoters were rather hypomethylated. Mutants with reduced non-CG methylation developed larger tumors than the wild-type controls, indicating that hypermethylation inhibits plant tumor growth. The differential methylation pattern of crown galls and the stem tissue from which they originate correlated with transcriptional changes. Genes known to be transcriptionally inhibited by ABA and methylated in crown galls became promoter methylated upon treatment of A. thaliana with ABA. This suggests that the high ABA levels in crown galls may mediate DNA methylation and regulate expression of genes involved in drought stress protection. In summary, our studies provide evidence that epigenetic processes

  5. Comparison of the arithmetic and geometric means in estimating crown diameter and crown cross-sectional area

    Science.gov (United States)

    KaDonna Randolph

    2010-01-01

    The use of the geometric and arithmetic means for estimating tree crown diameter and crown cross-sectional area were examined for trees with crown width measurements taken at the widest point of the crown and perpendicular to the widest point of the crown. The average difference between the geometric and arithmetic mean crown diameters was less than 0.2 ft in absolute...

  6. Ecology and conservation of the crowned lemur, Lemur coronatus, at Ankarana, n. Madagascar. With notes on Sanford's lemur, other sympatrics and subfossil lemurs.

    Science.gov (United States)

    Wilson, J M; Stewart, P D; Ramangason, G S; Denning, A M; Hutchings, M S

    1989-01-01

    Forests of Ankarana limestone massif in northern Madagascar support one of the largest and least disturbed populations of Crowned Lemurs, Lemur coronatus. This paper reports a preliminary study of the ecology of this species in the Ankarana Special Reserve conducted at the end of the dry season in 1986, with additional information collected a year later. Crowned Lemurs occur in very high densities in the semi-deciduous canopy forest and this probably represents a dry season refuge for the species. They also use more open habitats, including sparsely vegetated limestone and degraded forest. Sanford's Lemur, Lemur fulvus sanfordi, also inhabits the Ankarana forests but is most abundant in degraded habitats. Crowned and Sanford's Lemurs had similar patterns of activity, which included nocturnal travelling and feeding bouts. Crowned Lemurs proved to be unusual among Lemur species in displaying low spatial troop cohesion and a lack of obvious troop hierarchy. Stronglyoides-like enteric helminths infested about one third of Crowned Lemurs but were apparently not causing disease. Crowned Lemurs fall prey to the Fosa, Cryptoprocta ferox, and the young possibly also to the largest raptors. A total of seven living lemur species (including the very rare Propithecus diadema perrieri and Daubentonia madagascariensis) were confirmed at Ankarana by the authors, and three further species have been reported by other observers. In addition to these ten extant lemurs, four subfossil species have been discovered: three of them (Hapalemur simus, Palaeopropithecus and Mesopropithecus) by the authors. The possibility that all 14 lemurs were once sympatric is discussed. For the present, the lemurs of Ankarana are protected from hunting by local taboo. Nevertheless they are under severe threat from habitat destruction, despite Ankarana's Special Reserve status. Given the very restricted distributions of Crowned and Sanford's Lemurs, both must be considered as threatened with extinction.

  7. High Fat, High Fructose, High Cholesterol Feeding Causes Severe NASH and Cecal Microbiota Dysbiosis in Juvenile Ossabaw Swine.

    Science.gov (United States)

    Panasevich, Matthew R; Meers, Grace M; Linden, Melissa A; Booth, Frank W; Perfield, James W; Fritsche, Kevin L; Wankhade, Umesh D; Chintapalli, Sree V; Shankar, Kartik; Ibdah, J A; Rector, R Scott

    2017-09-12

    Pediatric obesity and nonalcoholic steatohepatitis (NASH) are on the rise in industrialized countries, yet our ability to mechanistically examine this relationship is limited by the lack of a suitable higher animal model. Here, we examined the effects of high fat, high fructose corn syrup, high cholesterol Western style diet (WD)-induced obesity on NASH and cecal microbiota dysbiosis in juvenile Ossabaw swine. Juvenile female Ossabaw swine (5 weeks old) were fed WD (43.0% fat; 17.8% high fructose corn syrup; 2% cholesterol) or low-fat diet (CON/lean; 10.5% fat) for 16 wks (n=6 each) or 36 wks (n=4 each). WD-fed pigs developed obesity, dyslipidemia, and systemic insulin resistance compared with CON pigs. In addition, obese WD-fed pigs developed severe NASH, with hepatic steatosis, hepatocyte ballooning, inflammatory cell infiltration, and fibrosis after 16 weeks, with further exacerbation of histological inflammation and fibrosis after 36 wks of WD-feeding. WD-feeding also resulted in robust cecal microbiota changes including increased relative abundances of families and genera in Proteobacteria (Phigh fat, high fructose, high cholesterol diet develop obesity and severe microbiota dysbiosis with a pro-inflammatory signature and a NASH phenotype directly relevant to the pediatric/adolescent and young adult population. Copyright © 2017, American Journal of Physiology-Endocrinology and Metabolism.

  8. Crown sealing and buckling instability during water entry of spheres

    KAUST Repository

    Marston, J. O.

    2016-04-05

    We present new observations from an experimental investigation of the classical problem of the crown splash and sealing phenomena observed during the impact of spheres onto quiescent liquid pools. In the experiments, a 6 m tall vacuum chamber was used to provide the required ambient conditions from atmospheric pressure down to of an atmosphere, whilst high-speed videography was exploited to focus primarily on the above-surface crown formation and ensuing dynamics, paying particular attention to the moments just prior to the surface seal. In doing so, we have observed a buckling-type azimuthal instability of the crown. This instability is characterised by vertical striations along the crown, between which thin films form that are more susceptible to the air flow and thus are drawn into the closing cavity, where they atomize to form a fine spray within the cavity. To elucidate to the primary mechanisms and forces at play, we varied the sphere diameter, liquid properties and ambient pressure. Furthermore, a comparison between the entry of room-temperature spheres, where the contact line pins around the equator, and Leidenfrost spheres (i.e. an immersed superheated sphere encompassed by a vapour layer), where there is no contact line, indicates that the buckling instability appears in all crown sealing events, but is intensified by the presence of a pinned contact line. © 2016 Cambridge University Press.

  9. 18-crown-6-sodium cholate complex: thermochemistry, structure, and stability.

    Science.gov (United States)

    Mihelj, Tea; Tomašić, Vlasta; Biliškov, Nikola

    2014-06-03

    18-Crown-6, one of the most relevant crown ethers, and sodium cholate, a steroidal surfactant classified as a natural bile salt, are components of a novel, synthesized coordination complex: 18-crown-6-sodium cholate (18C6·NaCh). Like crown ethers, bile salts act as building blocks in supramolecular chemistry to design new functionalized materials with a desired structure and properties. In order to obtain thermal behavior of this 1:1 coordination complex, thermogravimetry and differential thermal analysis were used, as well as microscopic observations and differential scanning calorimetry. Temperature dependent infrared (IR) spectroscopy gave a detailed view into phase transitions. The structures during thermal treatment were observed with powder X-ray diffraction, and molecular models of the phases were made. Hard, glassy, colorless compound 18C6·NaCh goes through crystalline-crystalline polymorphic phase transitions at higher temperatures. The room temperature phase is indexed to a triclinic lattice, while in the high temperature phases molecules take randomly one of the two different configurations in the unit cell, resulting in the 2-fold symmetry. The formation of cholesteric liquid crystalline phase occurs simultaneously with partial decomposition, followed by the isotropization with simultaneous and complete decomposition at much higher temperature, as obtained by IR. The results provide valuable information about the relationship between molecular structure, thermal properties, and stability of the complex, indicating the importance of an appropriate choice of cation, amphiphilic, and crown ether unit in order to synthesize compounds with desired behavior.

  10. Digital modeling technology for full dental crown tooth preparation.

    Science.gov (United States)

    Dai, Ning; Zhong, Yicheng; Liu, Hao; Yuan, Fusong; Sun, Yuchun

    2016-04-01

    A dental defect is one of the most common oral diseases, and it often requires a full crown restoration. In this clinical operation, the dentist must manually prepare the affected tooth for the full crown so that it has a convergence angle between 4° and 10°, no undercuts, and uniform and even shoulder widths and depths using a high speed diamond bur in the patient׳s mouth within one hour, which is a difficult task that requires visual-manual operation. The quality of the tooth preparation has an important effect on the success rate of the subsequent prosthodontic treatment. This study involved research into digital modeling technology for full dental crown tooth preparation. First, the margin line of the tooth preparation was designed using a semi-automatic interactive process. Second, the inserting direction was automatically computed. Then, the characteristic parameters and the constraints on the tooth preparation were defined for the model. Next, the shoulder and axial surface of the tooth preparation were formed using parametric modeling. Finally, the implicit surface of a radial basis function was used to construct the tooth preparation׳s occlusal surface. The experimental results verified that the method of digital modeling for full crown preparation proposed in this study can quickly and accurately implement personalized designs of various parameters, such as the shoulder width and the convergence angle; it provides a digital design tool for full crown preparation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Morphological and compositional alterations of in vivo aged prefabricated pediatric metal crowns (PMCs).

    Science.gov (United States)

    Zinelis, Spiros; Lambrinaki, Tina; Kavvadia, Katerina; Papagiannoulis, Lisa

    2008-02-01

    The purpose of the present study was to assess the morphological and elemental alterations of retrieved prefabricated metal crowns (PMCs) after intraoral exposure. Seventeen in vivo aged stainless steel crowns (3M ESPE) were collected. The intraoral exposure time varied from 3 to 101 months. For every retrieved crown one new crown of the same type was used as a reference. The reference and in vivo aged crowns were examined by high-vacuum scanning electron microscopy and energy-dispersive X-ray microanalysis. The elemental composition between the as-received and in vivo aged crowns was statistically analyzed by t-test (a=0.05). In vivo aged crown surfaces demonstrated significantly morphological alterations with accumulation of amorphous intraoral integuments, biting imprints, wear and occlusal perforations. The results of microanalysis showed that there were no statistically significant differences in the elemental composition of the stainless steel crowns between the two conditions. Under the conditions of the present study, retrieved prefabricated pediatric stainless steel crowns exhibit morphological changes mainly due to plastic deformation, without changes in elemental composition.

  12. Clinical success and parental satisfaction with anterior preveneered primary stainless steel crowns.

    Science.gov (United States)

    Shah, Purvi V; Lee, Jessica Y; Wright, J Timothy

    2004-01-01

    The purpose of this study was to evaluate the clinical success of and parental satisfaction with treatment using prefabricated resin-faced stainless steel crowns (SSCs; Kinder Krowns, Mayclin Dental Studios, Minneapolis, Minn) on anterior primary teeth. Patients treated with Kinder Krowns within the last 3 years were recalled for dinical evaluation and completion of a parental satisfaction survey in this retrospective cross-sectional study. Clinical evaluation was performed for crown retention, facing retention, and resin veneer wear. Forty-six teeth were evaluated in 12 children. The average age of the crown at the time of examination was 17.5 months (range 5-38 months). All crowns were present in the mouth, and resin fracture resulting in partial or total facing loss was seen in 24% of the crowns. No resin facing fracture or visible wear was seen in 61% of the crowns. Six crowns had total facing loss from fracture (13%), while 5 (11%) had partial facing fracture. Wear (7 crowns, 15%) was limited to less than the incisal one third of the crown. The parental satisfaction with the preveneered SSCs overall was high, with satisfaction for appearance and the shape being the lowest. Kinder Krown prefabricated resin-faced SSCs showed a low failure rate, and the parental satisfaction with treatment was positive.

  13. Measuring residual stress in ceramic zirconia-porcelain dental crowns by nanoindentation.

    Science.gov (United States)

    Zhang, Y; Allahkarami, M; Hanan, J C

    2012-02-01

    Residual stress plays a critical role in failure of ceramic dental crowns. The magnitude and distribution of residual stress in the crown system are largely unknown. Determining the residual stress quantitatively is challenging since the crown has such complex contours and shapes. This work explored the feasibility and validity of measuring residual stress of zirconia and porcelain in ceramic crowns by nanoindentation. Nanoindentation tests were performed on the cross-section of a crown for both porcelain and zirconia along four critical locations: the thickest, thinnest and medium porcelain thicknesses. Zirconia and porcelain pieces, chipped off from the crown and annealed at 400 °C, were used as reference samples. The residual stress was determined by comparing the measured hardness of the stressed sample with that of the reference sample. Nanoindentation impression images were acquired through a scanning probe microscope (SPM) equipped with a Hysitron Triboindenter. Zirconia showed large pile-up. Residual stress is determined along the thickness of crowns at the chosen locations for both porcelain and zirconia. The measured results were compared with the results from X-ray diffraction (XRD) and finite element modeling (FEM). Results show there are large amounts of residual stresses in the dental crown and their magnitude differs between locations due to the complex shape of the crown. The average residual stress readings were as high as -637 MPa and 323 MPa for zirconia and porcelain respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Chipping resistance of graded zirconia ceramics for dental crowns.

    Science.gov (United States)

    Zhang, Y; Chai, H; Lee, J J-W; Lawn, B R

    2012-03-01

    A serious drawback of veneering porcelains is a pronounced susceptibility to chipping. Glass-infiltrated dense zirconia structures can now be produced with esthetic quality, making them an attractive alternative. In this study, we examined the hypothesis that such infiltrated structures are much more chip-resistant than conventional porcelains, and at least as chip-resistant as non-infiltrated zirconia. A sharp indenter was used to produce chips in flat and anatomically correct glass-infiltrated zirconia crown materials, and critical loads were measured as a function of distance from the specimen edge (flat) or side wall (crown). Control data were obtained on zirconia specimens without infiltration and on crowns veneered with porcelains. The results confirmed that the resistance to chipping in graded zirconia is more than 4 times higher than that of porcelain-veneered zirconia and is at least as high as that of non-veneered zirconia.

  15. Chipping Resistance of Graded Zirconia Ceramics for Dental Crowns

    Science.gov (United States)

    Zhang, Y.; Chai, H.; Lee, J.J.-W.; Lawn, B.R.

    2012-01-01

    A serious drawback of veneering porcelains is a pronounced susceptibility to chipping. Glass-infiltrated dense zirconia structures can now be produced with esthetic quality, making them an attractive alternative. In this study, we examined the hypothesis that such infiltrated structures are much more chip-resistant than conventional porcelains, and at least as chip-resistant as non-infiltrated zirconia. A sharp indenter was used to produce chips in flat and anatomically correct glass-infiltrated zirconia crown materials, and critical loads were measured as a function of distance from the specimen edge (flat) or side wall (crown). Control data were obtained on zirconia specimens without infiltration and on crowns veneered with porcelains. The results confirmed that the resistance to chipping in graded zirconia is more than 4 times higher than that of porcelain-veneered zirconia and is at least as high as that of non-veneered zirconia. PMID:22232142

  16. An alternative method for estimating crown characteristics of urban trees using digital photographs

    Science.gov (United States)

    Matthew F. Winn; Philip A. Araman

    2012-01-01

    The USDA Forest Service Forest Inventory and Analysis (FIA) program has concluded that statewide urban forest inventories are feasible based on a series of pilot studies initiated in 2001. However, much of the tree crown data collected during inventories are based on visual inspection and therefore highly subjective. In order to objectively determine the crown...

  17. In situ quantification of experimental ice accretion on tree crowns using terrestrial laser scanning.

    Science.gov (United States)

    Nock, Charles A; Greene, David; Delagrange, Sylvain; Follett, Matt; Fournier, Richard; Messier, Christian

    2013-01-01

    In the eastern hardwood forests of North America ice storms are an important disturbance event. Ice storms strongly influence community dynamics as well as urban infrastructure via catastrophic branch failure; further, the severity and frequency of ice storms are likely to increase with climate change. However, despite a long-standing interest into the effects of freezing rain on forests, the process of ice accretion and thus ice loading on branches remains poorly understood. This is because a number of challenges have prevented in situ measurements of ice on branches, including: 1) accessing and measuring branches in tall canopies, 2) limitations to travel during and immediately after events, and 3) the unpredictability of ice storms. Here, utilizing a novel combination of outdoor experimental icing, manual measurements and terrestrial laser scanning (TLS), we perform the first in situ measurements of ice accretion on branches at differing heights in a tree crown and with increasing duration of exposure. We found that TLS can reproduce both branch and iced branch diameters with high fidelity, but some TLS instruments do not detect ice. Contrary to the expectations of ice accretion models, radial accretion varied sharply within tree crowns. Initially, radial ice accretion was similar throughout the crown, but after 6.5 hours of irrigation (second scanning) radial ice accretion was much greater on upper branches than on lower (∼factor of 3). The slope of the change in radial ice accretion along branches increased with duration of exposure and was significantly greater at the second scanning compared to the first. We conclude that outdoor icing experiments coupled with the use of TLS provide a robust basis for evaluation of models of ice accretion and breakage in tree crowns, facilitating estimation of the limiting breaking stress of branches by accurate measurements of ice loads.

  18. In situ quantification of experimental ice accretion on tree crowns using terrestrial laser scanning.

    Directory of Open Access Journals (Sweden)

    Charles A Nock

    Full Text Available In the eastern hardwood forests of North America ice storms are an important disturbance event. Ice storms strongly influence community dynamics as well as urban infrastructure via catastrophic branch failure; further, the severity and frequency of ice storms are likely to increase with climate change. However, despite a long-standing interest into the effects of freezing rain on forests, the process of ice accretion and thus ice loading on branches remains poorly understood. This is because a number of challenges have prevented in situ measurements of ice on branches, including: 1 accessing and measuring branches in tall canopies, 2 limitations to travel during and immediately after events, and 3 the unpredictability of ice storms. Here, utilizing a novel combination of outdoor experimental icing, manual measurements and terrestrial laser scanning (TLS, we perform the first in situ measurements of ice accretion on branches at differing heights in a tree crown and with increasing duration of exposure. We found that TLS can reproduce both branch and iced branch diameters with high fidelity, but some TLS instruments do not detect ice. Contrary to the expectations of ice accretion models, radial accretion varied sharply within tree crowns. Initially, radial ice accretion was similar throughout the crown, but after 6.5 hours of irrigation (second scanning radial ice accretion was much greater on upper branches than on lower (∼factor of 3. The slope of the change in radial ice accretion along branches increased with duration of exposure and was significantly greater at the second scanning compared to the first. We conclude that outdoor icing experiments coupled with the use of TLS provide a robust basis for evaluation of models of ice accretion and breakage in tree crowns, facilitating estimation of the limiting breaking stress of branches by accurate measurements of ice loads.

  19. Modelling initial mortality of Abies religiosa in a crown fire in Mexico

    Directory of Open Access Journals (Sweden)

    Salomé Temiño-Villota

    2016-04-01

    Full Text Available Aim of study: The objectives of this work were to determine which morphological and fire severity variables may help explain the mortality of adult Abies religiosa (Kunth Schltdl. & Cham., to model the probability of this species after being affected by crown fire, and to obtain more elements to classify the sacred fir in terms of fire resistance. This type of studies are relevant to estimate the impact of crown fires on the climax forests that forms this species.Area of study: The burned forest was located in the southern Mexico City, borough.Material and methods: Morphological variables and fire severity indicators were collected for 335 Abies religiosa trees burned by a mixed severity fire. Logistic regression was used to analyze data and develop models that best explained tree mortality.Main results: Survival was 26.9%. The models for height (p≤0.0001, diameter at breast height (p=0.0082, crown length (p≤0.0001 and crown base height (p≤0.0001 were significant, with a negative relationship between each one of these variables and probability of mortality. The significant severity variables were lethal scorch height (p≤0.0001 and crown kill (p≤ 0.0001, which have a direct relationship with probability of mortality.Highlights: This species is moderately fire-resistant. Crown kill ≥ 70% markedly increases mortality. Silvicultural activities such as pruning, thinning and fuel management can reduce the risk of crown fires.

  20. Modelling initial mortality of Abies religiosa in a crown fire in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Temiño-Villota, S.; Rodríguez-Trejo, D.A.; Molina Terrén, D.M.; Ryan, K.

    2016-07-01

    Aim of the study: The objectives of this work were to determine which morphological and fire severity variables may help explain the mortality of adult Abies religiosa (Kunth) Schltdl. & Cham., to model the probability of this species after being affected by crown fire, and to obtain more elements to classify the sacred fir in terms of fire resistance. This type of studies are relevant to estimate the impact of crown fires on the climax forests that forms this species. Area of study: The burned forest was located in the southern Mexico City, borough. Material and methods: Morphological variables and fire severity indicators were collected for 335 Abies religiosa trees burned by a mixed severity fire. Logistic regression was used to analyze data and develop models that best explained tree mortality. Main results: Survival was 26.9%. The models for height (p≤0.0001), diameter at breast height (p=0.0082), crown length (p≤0.0001) and crown base height (p≤0.0001) were significant, with a negative relationship between each one of these variables and probability of mortality. The significant severity variables were lethal scorch height (p≤0.0001) and crown kill (p≤ 0.0001), which have a direct relationship with probability of mortality. Highlights: This species is moderately fire-resistant. Crown kill ≥ 70% markedly increases mortality. Silvicultural activities such as pruning, thinning and fuel management can reduce the risk of crown fires. (Author)

  1. Evaluating ceramic crown margins with digital radiography.

    Science.gov (United States)

    Wahle, William Maxwell; Masri, Radi; Driscoll, Carl; Romberg, Elaine

    2017-09-29

    Radiographs aid in clinically determining crown fit, specifically interproximal margins where tactile and visual methods may be limited. However, investigations of the utility of digital radiographs as a tool for evaluating the marginal openings of ceramic crowns are lacking. The purpose of this in vitro study was to assess whether marginal adaptation for ceramic crowns and for metal-ceramic crowns with a metal collar can be identified with digital radiographs. One lithium disilicate crown, 1 fluorapatite crown, and 1 metal-ceramic crown were fabricated for a maxillary premolar. The crowns were attached to a custom-designed device that allowed the marginal discrepancy to be changed. A total of 10 increments were measured starting at 0 to 20 μm and increasing every 20 μm to a maximum opening of 180 to 200 μm. At each increment, 2 radiographs were made of the crowns, using a digital sensor, 1 perpendicular to and 1 at 80 degrees to the long axis of the tooth. To test whether digital radiographs could be used to accurately identify "acceptable" and "unacceptable" margins, 21 dentists were asked to rate the radiographs as "acceptable" or "unacceptable." The chi square test was used to analyze differences between the dentists' evaluations and the actual marginal opening (α=.05). For the purposes of this study, a marginal discrepancy greater than 80 μm was considered "unacceptable." Of all marginal discrepancies exceeding 80 μm, 78.6% of the metal-ceramic crown radiographs were incorrectly scored as "acceptable" (Ptested metal-ceramic crowns tended to be evaluated incorrectly as acceptable. The marginal fit of the tested ceramic crowns tended to be evaluated incorrectly as unacceptable. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  2. Pericoronal radiolucency associated with incomplete crown

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Kyung Soo [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2013-12-15

    The author experienced 8 cases of pericoronal radiolucency involving an incomplete tooth crown that had not developed to form the cemento-enamel junction, and the underdeveloped crown sometimes appeared to be floating within the radiolucency radiographically. The first impression was that these cystic lesions had odontogenic keratocysts, but half of them turned out to be dentigerous cysts histopathologically. There has been no report concerning odontogenic cysts involving an incompletely developed crown. The purpose of this paper is to report that dentigerous cysts may develop before the completion of the cemento-enamel junction of a developing crown.

  3. Fracture resistance of various temporary crown materials.

    Science.gov (United States)

    Yilmaz, Asude; Baydaş, Seyfettin

    2007-01-01

    The aim of this study was to evaluate the fracture resistance of various provisional crown materials using an in vitro model test system. In the present study polycarbonate crowns, prefabricated by the manufacturer (3M Polycarbonate Crown), and the temporary crowns, fabricated in the dental laboratory environment, were fabricated using bis-acryl composite (Protemp II), autopolymerizing PMMA resin (BISICO Temp S), and heat-polymerized PMMA resin (Major C&B-V Dentine). All temporary crowns were stored in distilled water for 24 hours at room temperature prior to testing. The crowns were seated on metal dies, fabricated from Cr-Co alloy (AZ Dental, Konstanz, Germany), and then tested using the indenter of a Hounsfield testing machine (Hounsfield Tensometer, Hounsfield Test Equipment, Raydon, England). The tip of the indenter was located at a position one-third of the way down the inciso-palatine surface at 135 masculine. The data were statistically analyzed for differences using one-way analysis of variance (ANOVA) and the Tukey HSD test (P polycarbonate crowns were significantly different from the BISICO Temp S, Protemp II, and Major C&B-V Dentine (P polycarbonate crowns may be preferable to the other types of temporary crowns used in this study.

  4. Radiolucency below the crown of mandibular horizontal incompletely impacted third molars and acute inflammation in men with diabetes

    Directory of Open Access Journals (Sweden)

    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

  5. Museum security and the Thomas Crown Affair.

    Energy Technology Data Exchange (ETDEWEB)

    Michaud, E. C. (Nuclear Engineering Division)

    2010-01-01

    Over the years, I've daydreamed about stealing a Vermeer, a Picasso, or Rembrandt. It tickles me, as much as watching the reboot of The Thomas Crown Affair. Why is it, do you suppose, so much fun to think about stealing a world renowned piece off the wall of a major metropolitan museum? Is it the romantic thoughts of getting away with it, walking past infrared detectors, and pressure sensors ala Indiana Jones with the sack of sand to remove the idol without triggering the security system? Is it the idea of snatching items with such fantastic prices, where the romance of possessing an item of such value is less intoxicating than selling it to a private collector for it to never be seen again? I suspect others share my daydreams as they watch theater or hear of a brazen daylight heist at museums around the world, or from private collections. Though when reality sets in, the mind of the security professional kicks in. How could one do it, why would one do it, what should you do once it's done? The main issue a thief confronts when acquiring unique goods is how to process or fence them. They become very difficult to sell because they are one-of-a-kind, easy to identify, and could lead to the people involved with the theft. The whole issue of museum security takes up an ironic twist when one considers the secretive British street artist 'Banksy'. Banksy has made a name for himself by brazenly putting up interesting pieces of art in broad daylight (though many critics don't consider his work to be art) on building walls, rooftops, or even museums. I bring him up for a interesting take on what may become a trend in museum security. In March of 2005, Banksy snuck a piece of his called 'Vandalized Oil Painting' into the Brooklyn Museum's Great Historical Painting Wing, plus 3 other pieces into major museums in New York. Within several days, 2 paintings had been torn down, but 2 stayed up much longer. In his home country of the UK, a

  6. Incorporating crown dimensions into stem height and basal area for ...

    African Journals Online (AJOL)

    Four crown dimensions (crown diameter, crown projection area, crown length and crown ratio) were each incorporated into nonlinear individual tree total height and basal area increment models for African white wood (Triplochiton scleroxylon K. Schum). The basic height/basal area growth model was formulated as a ...

  7. Tree crown conditions in Missouri, 2000-2003

    Science.gov (United States)

    KaDonna C. Randolph; W. Keith Moser

    2009-01-01

    The Forest Service, U.S. Department of Agriculture, Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes three FIA tree crown condition indicators (crown dieback, crown density, and foliage transparency) and sapling crown vigor measured in Missouri between 2000...

  8. Marginal adaptation and fracture resistance of adhesively luted glass fibre-composite reinforced molar crowns with different inner crown surfaces.

    Science.gov (United States)

    Behr, M; Rosentritt, M; Sikora, M I; Karl, P; Handel, G

    2003-09-01

    This study compared the influence of different inner crown surfaces on the fracture resistance and marginal adaptation of adhesively fixed glass fibre-reinforced molar crowns. Vectris/Targis crowns were constructed with an inner framework of glass fibres (directly on the tooth) or an inner veneering composite layer between the fibre-framework and the tooth-substance. Both groups were sandblasted inside using Al(2)O(3); 50 microm grain size (200 kPa, 20 s) and silane coated. A control group had the inner fibre framework, but was neither sandblasted nor silane coated. The crowns were adhesively cemented on extracted human teeth, and thermally cycled and mechanically loaded (TCML: 6000 x 5 degrees C/55 degrees C; 1.2 x 10(6) x 50 N, 1.66 Hz). The marginal adaptation before and after TCML was evaluated and the fracture resistance was investigated using a Zwick universal testing machine. After TCML the proportion of 'perfect margin' of the control group decreased significantly at the interface crown/cement. For the variations with an inner fibre framework or inner composite layer the marginal adaptation or fracture resistance did not decrease significantly after ageing. The fracture resistance values were control: 1509N+/-486; inner fibre framework: 1896N+/-342; inner composite layer: 1754N+/-340. In the case of the investigated fibre framework and veneering composite, the inner surface of glass fibre-reinforced molar crowns can be covered with a composite layer or with a glass fibre framework. Both methods achieve comparable high fracture strengths and reliable marginal adaptation.

  9. Studies of a pyridino-crown ether-based chiral stationary phase on the enantioseparation of biogenic chiral aralkylamines and α-amino acid esters by high-performance liquid chromatography.

    Science.gov (United States)

    Lévai, Sándor; Németh, Tamás; Fődi, Tamás; Kupai, József; Tóth, Tünde; Huszthy, Péter; Balogh, György Tibor

    2015-11-10

    This paper reports the enantioseparation ability of a pyridino-18-crown-6 ether-based chiral stationary phase [(S,S)-CSP-1]. The enantiomeric discrimination of chiral stationary phase (S,S)-CSP-1 was evaluated by HPLC using the mixtures of enantiomers of various protonated primary aralkylamines [1-phenylethylamine hydrogen perchlorate (PEA), 2,3-dihydro-1H-inden-1-amine (1-aminoindan), 2,2'-(1,2-diaminoethane-1,2-diyl) diphenol (HPEN)] and perchlorate salts of α-amino acid esters [alanine benzyl ester (Ala-OBn), phenylalanine benzyl ester (Phe-OBn), phenylalanine methyl ester (Phe-OMe), phenylglycine methyl ester (PhGly-OMe), glutamic acid dibenzyl ester (Glu-diOBn), and valine benzyl ester (Val-OBn)]. The best enantioseparation was achieved in the case of PEA. The high enantioselectivity was rationalized by the strong π-π interaction of the extended π system of the aryl-substituted pyridine unit. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Calix[4]-bis-crowns and calix[4]-bis-aza-oxa-crowns: from receptors design to molecular machines

    Energy Technology Data Exchange (ETDEWEB)

    Asfari, Z.; Nierlich, M.; Thuery, P.; Lamare, V.; Dozol, J.F.; Leroy, M.; Vicens, J. [CEA, Cadarache, Saint Paul-lez-Durance, (France)

    1996-11-01

    This review article mainly collects our results on the complexation properties of a series of 1,3-calix[4]-bis-crowns in the 1,3-alternate conformation. Due to their high symmetry, these receptors were shown to form mono-and bi-nuclear complexes with alkali metal cations as evidenced by X-ray crystallography and NMR investigations. Among the family those receptors containing 6 oxygen atoms in the poly glycolic chains were proved to be highly selective towards cesium cation. The observed Na+/Cs+ selectivity was exploited in separation process using them as carriers in transport through supported liquid membranes (SLMs). The selectivity was also rationalized through the determination of thermodynamical parameters of the complexation. X-ray structures and molecular modelling showed that the ligands are preorganised to complex cesium cations and were accounted for explaining the high selectivity observed during the transport experiments. ``1 H- and ``133Cs-NMR grave a schematic representation of the formation of binuclear species and of tunneling of the metal through the calixarene unit. Calix[4]-bis-aza-oxa-crowns and related hybrid receptors combining poly oxa aza-and poly oxa crown ether elements which have been synthesized are good candidates for acting as hard-soft receptors. Due to the globular shapes of calix[4]-bis-crowns, molecular world globes as new molecular machines have been prepared. (Author)29 refs.

  11. GRL-09510, a Unique P2-Crown-Tetrahydrofuranylurethane -Containing HIV-1 Protease Inhibitor, Maintains Its Favorable Antiviral Activity against Highly-Drug-Resistant HIV-1 Variants in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Masayuki; Miguel Salcedo-Gómez, Pedro; Yedidi, Ravikiran S.; Delino, Nicole S.; Nakata, Hirotomo; Venkateswara Rao, Kalapala; Ghosh, Arun K.; Mitsuya, Hiroaki

    2017-09-25

    We report that GRL-09510, a novel HIV-1 protease inhibitor (PI) containing a newly-generated P2-crown-tetrahydrofuranylurethane (Crwn-THF), a P2'-methoxybenzene, and a sulfonamide isostere, is highly active against laboratory and primary clinical HIV-1 isolates (EC50: 0.0014–0.0028 μM) with minimal cytotoxicity (CC50: 39.0 μM). Similarly, GRL-09510 efficiently blocked the replication of HIV-1NL4-3 variants, which were capable of propagating at high-concentrations of atazanavir, lopinavir, and amprenavir (APV). GRL-09510 was also potent against multi-drug-resistant clinical HIV-1 variants and HIV-2ROD. Under the selection condition, where HIV-1NL4-3 rapidly acquired significant resistance to APV, an integrase inhibitor raltegravir, and a GRL-09510 congener (GRL-09610), no variants highly resistant against GRL-09510 emerged over long-term in vitro passage of the virus. Crystallographic analysis demonstrated that the Crwn-THF moiety of GRL-09510 forms strong hydrogen-bond-interactions with HIV-1 protease (PR) active-site amino acids and is bulkier with a larger contact surface, making greater van der Waals contacts with PR than the bis-THF moiety of darunavir. The present data demonstrate that GRL-09510 has favorable features for treating patients infected with wild-type and/or multi-drug-resistant HIV-1 variants, that the newly generated P2-Crwn-THF moiety confers highly desirable anti-HIV-1 potency. The use of the novel Crwn-THF moiety sheds lights in the design of novel PIs.

  12. Towards an Optimized Method of Olive Tree Crown Volume Measurement

    Directory of Open Access Journals (Sweden)

    Antonio Miranda-Fuentes

    2015-02-01

    Full Text Available Accurate crown characterization of large isolated olive trees is vital for adjusting spray doses in three-dimensional crop agriculture. Among the many methodologies available, laser sensors have proved to be the most reliable and accurate. However, their operation is time consuming and requires specialist knowledge and so a simpler crown characterization method is required. To this end, three methods were evaluated and compared with LiDAR measurements to determine their accuracy: Vertical Crown Projected Area method (VCPA, Ellipsoid Volume method (VE and Tree Silhouette Volume method (VTS. Trials were performed in three different kinds of olive tree plantations: intensive, adapted one-trunked traditional and traditional. In total, 55 trees were characterized. Results show that all three methods are appropriate to estimate the crown volume, reaching high coefficients of determination: R2 = 0.783, 0.843 and 0.824 for VCPA, VE and VTS, respectively. However, discrepancies arise when evaluating tree plantations separately, especially for traditional trees. Here, correlations between LiDAR volume and other parameters showed that the Mean Vector calculated for VCPA method showed the highest correlation for traditional trees, thus its use in traditional plantations is highly recommended.

  13. Towards an Optimized Method of Olive Tree Crown Volume Measurement

    Science.gov (United States)

    Miranda-Fuentes, Antonio; Llorens, Jordi; Gamarra-Diezma, Juan L.; Gil-Ribes, Jesús A.; Gil, Emilio

    2015-01-01

    Accurate crown characterization of large isolated olive trees is vital for adjusting spray doses in three-dimensional crop agriculture. Among the many methodologies available, laser sensors have proved to be the most reliable and accurate. However, their operation is time consuming and requires specialist knowledge and so a simpler crown characterization method is required. To this end, three methods were evaluated and compared with LiDAR measurements to determine their accuracy: Vertical Crown Projected Area method (VCPA), Ellipsoid Volume method (VE) and Tree Silhouette Volume method (VTS). Trials were performed in three different kinds of olive tree plantations: intensive, adapted one-trunked traditional and traditional. In total, 55 trees were characterized. Results show that all three methods are appropriate to estimate the crown volume, reaching high coefficients of determination: R2 = 0.783, 0.843 and 0.824 for VCPA, VE and VTS, respectively. However, discrepancies arise when evaluating tree plantations separately, especially for traditional trees. Here, correlations between LiDAR volume and other parameters showed that the Mean Vector calculated for VCPA method showed the highest correlation for traditional trees, thus its use in traditional plantations is highly recommended. PMID:25658396

  14. Development of Instrument Transmitter Protecting Device against High-Temperature Condition during Severe Accidents

    Directory of Open Access Journals (Sweden)

    Min Yoo

    2014-01-01

    Full Text Available Reliable information through instrumentation systems is essential in mitigating severe accidents such as the one that occurred at the Fukushima Daiichi nuclear power plant. There are five elements which might pose a potential threat to the reliability of parameter detection at nuclear power plants during a severe accident: high temperature, high pressure, high humidity, high radiation, and missiles generated during the evolution of a severe accident. Of these, high temperature apparently poses the most serious threat, since thin shielding can get rid of pressure, humidity, radiation (specifically, alpha and beta radiations, and missile effects. In view of this fact, our study focused on designing an instrument transmitter protecting device that can eliminate the high-temperature effect on transmitters to maintain their functional integrity. We present herein a novel concept for designing such a device in terms of heat transfer model that takes into account various heat transfer mechanisms associated with the device.

  15. Dimethylammonium perchlorate 18-crown-6 monohydrate clathrate

    Directory of Open Access Journals (Sweden)

    Jia-Zhen Ge

    2010-07-01

    Full Text Available The reaction of dimethylamine, 18-crown-6, and perchloric acid in methanol yields the title compound, C2H8N+·ClO4−·C12H24O6·H2O. The dimethylammonium cation and the water molecule interact with the 18-crown-6 unit: N—H...O hydrogen bonds are formed between the ammonium NH2+ group and four O atoms of the crown ether, while the water molecule on the other side of 18-crown-6 ring forms O—H...O hydrogen bonds with two other O atoms of the crown ether. All conventional donors and acceptors in the cations are thus engaged in hydrogen bonding. The ClO4− anion is disordered over two sites, and occupancies for the disordered O atoms were fixed at 0.5. In the crystal, the cations and anions are arranged in alternating layers.

  16. Geographic access to high capability severe acute respiratory failure centers in the United States

    National Research Council Canada - National Science Library

    Wallace, David J; Angus, Derek C; Seymour, Christopher W; Yealy, Donald M; Carr, Brendan G; Kurland, Kristen; Boujoukos, Arthur; Kahn, Jeremy M

    2014-01-01

    .... We sought to measure geographic access to these centers in the United States. Cross-sectional analysis of geographic access to high capability severe acute respiratory failure centers in the United States...

  17. Comparison of internal fit between implant abutments and cast metal crowns vs laser-sintered crowns.

    Science.gov (United States)

    Kiliçarslan, Mehmet Ali; Özkan, Pelin; Uludag, Bülent; Mumcu, Emre

    2014-07-01

    A common problem related to cemented single crowns is the internal misfit, which may cause inadequate retention, especially when seated on the implant abutment. The aim of this study was to compare the internal fit of Co-Cr crowns using a traditional lost-wax casting technique from laser-sintered Co-Cr alloy crowns. Twelve metallic crowns per each technique were fabricated. The effect of the thickness of cement, originated internal gap was evaluated. Crowns were cemented on the implant abutments with resin cement, and the internal fit of crowns was measured at five areas with an optical microscope. The data were analyzed, and the means were compared with a t-test (pcrowns obtained through the lost wax method (min. 65.50 ± 9.54 μm and max. 313.46 ± 48.12 μm). The fit of the metal crown likely varies with the fabrication technique. The use of techniques that enable the adjustment of crown parameters, such as the laser sintering technique, maintains the desired fit between casting and implant abutments. This study investigated which technique affects the internal fit of cemented implant-supported crowns, comparing the use of lost wax casting and laser-sintered metal dental alloys. The results of this study indicate that the use of laser-sintered crowns can improve for crown accuracy.

  18. QTL analysis of crown rust resistance in perennial ryegrass under conditions of natural and artificial infection

    DEFF Research Database (Denmark)

    Schejbel, Britt; Jensen, Louise Friis Bach; Xing, Yongzhong

    2007-01-01

    Crown rust is an economically devastating disease of perennial ryegrass. Both artificial crown rust inoculations, with the possibility of several selection cycles in one year, as well as marker-assisted selection can be used for more efficient breeding of new resistant cultivars. The objective...... as well as by artificial pathogen inoculations using a detached leaf assessment. The broad sense heritability values for the field, detached leaf and combined assays were 0.42, 0.56, and 0.64, respectively, indicating a good potential for selection for crown rust resistance. A total of six QTLs were...

  19. Flipping the sign of refractive index changes in ultrafast and temporally shaped laser-irradiated borosilicate crown optical glass at high repetition rates

    Science.gov (United States)

    Mermillod-Blondin, A.; Burakov, I. M.; Meshcheryakov, Yu. P.; Bulgakova, N. M.; Audouard, E.; Rosenfeld, A.; Husakou, A.; Hertel, I. V.; Stoian, R.

    2008-03-01

    Ultrafast subpicosecond laser exposure usually induces negative refractive index changes in optical glasses with strong thermal expansion such as borosilicate BK7 due to volume expansion and mechanical rarefaction. We show that temporally shaped laser excitation on picosecond scales and at high repetition rates can invert the regular material response resulting in a significant refractive index increase. Simulations of pulse propagation and evolution of heat and strain waves in BK7 glass exposed to different pulse durations were performed to understand mechanisms of refractive index increase. Narrow spatial distribution of energy for optimized picosecond pulses determines shock-induced plastic deformations accompanied by partial healing of the lateral strain due to preferential heat flow. The matter momentum relaxation produces directional on-axis material compaction.

  20. The role of tyloses in crown hydraulic failure of mature walnut trees afflicted by apoplexy disorder.

    Science.gov (United States)

    McElrone, Andrew J; Grant, Joseph A; Kluepfel, Daniel A

    2010-06-01

    In the Central Valley of California, mature walnut trees afflicted with apoplexy disorder exhibit rapid and complete crown defoliation within a few weeks of symptom initiation. Symptoms are typically found throughout the entire crown and are initially expressed as wilting and chlorosis followed by scorching of leaves. Since the cause of apoplexy disorder is unknown, we set out to elucidate the water relations physiology underlying this condition. Stem water potential (Psi(s)) of healthy, asymptomatic trees remained high throughout the 2007 growing season, while that of apoplexy-afflicted trees decreased significantly with the onset of symptoms for both healthy-appearing and symptomatic portions of these trees. Psi(s)s were significantly reduced by at least 0.7 MPa in the lower, middle and upper portions of the symptomatic canopies compared with those from asymptomatic trees. Heat pulse velocities measured in the main trunk at three radial depths consistently decreased prior to the onset of symptoms and eventually reached zero with complete crown defoliation. Comparison of sap flow with predicted water use based on walnut evapotranspiration suggests that stomata of symptomatic trees were closing at higher evaporative demand prior to symptom formation. Specific hydraulic conductivity (K(s)) of symptomatic stems was significantly lower than that of asymptomatic stems, and no detectable K(s) could be measured on several of the symptomatic stem samples. However, shallow root K(s) did not significantly differ between symptomatic and asymptomatic trees, suggesting that hydraulic failure was isolated to the crown of these grafted trees. Light and scanning electron microscopy of stem and trunk sapwood revealed extensive tylose development in vessels throughout the crown of symptomatic trees. Analysis of the formation of tyloses on multiple dates revealed rapid development of these vessel occlusions in conjunction with visual symptom formation and dramatic decreases in sap

  1. Digital evaluation of the fit of zirconia-reinforced lithium silicate crowns with a new three-dimensional approach.

    Science.gov (United States)

    Zimmermann, Moritz; Valcanaia, Andre; Neiva, Gisele; Mehl, Albert; Fasbinder, Dennis

    2017-11-30

    Several methods for the evaluation of fit of computer-aided design/computer-assisted manufacture (CAD/CAM)-fabricated restorations have been described. In the study, digital models were recorded with an intraoral scanning device and were measured using a new three-dimensional (3D) computer technique to evaluate restoration internal fit. The aim of the study was to evaluate the internal adaptation and fit of chairside CAD/CAM-fabricated zirconia-reinforced lithium silicate ceramic crowns fabricated with different post-milling protocols. The null hypothesis was that different post-milling protocols did not influence the fitting accuracy of zirconia-reinforced lithium silicate restorations. A master all-ceramic crown preparation was completed on a maxillary right first molar on a typodont. Twenty zirconia-reinforced lithium silicate ceramic crowns (Celtra Duo, Dentsply Sirona) were designed and milled using a chairside CAD/CAM system (CEREC Omnicam, Dentsply Sirona). The 20 crowns were randomly divided into two groups based on post-milling protocols: no manipulation after milling (Group MI) and oven fired-glazing after milling (Group FG). A 3D computer method was used to evaluate the internal adaptation of the crowns. This was based on a subtractive analysis of a digital scan of the crown preparation and a digital scan of the thickness of the cement space over the crown preparation as recorded by a polyvinylsiloxane (PVS) impression material. The preparation scan and PVS scan were matched in 3D and a 3D difference analysis was performed with a software program (OraCheck, Cyfex). Three areas of internal adaptation and fit were selected for analysis: margin (MA), axial wall (AX), and occlusal surface (OC). Statistical analysis was performed using 80% percentile and one-way ANOVA with post-hoc Scheffé test (P = .05). The closest internal adaptation of the crowns was measured at the axial wall with 102.0 ± 11.7 µm for group MI-AX and 106.3 ± 29.3 µm for group FG

  2. PREFORMED METAL CROWNS AS A PROSTHETIC RESTORATIONS IN PEDIATRIC DENTISTRY

    OpenAIRE

    Evgeni Dimitrov; Milena Georgieva; Мariana Dimova-Gabrovska; Radosveta Andreeva; Ani Belcheva-Krivorova

    2017-01-01

    The preformed metal crowns (PMCs) are prefabricated constructions, used for restoring a severely broken teeth, affected by multisurfice carious lesions. The aim of the current study is to analyze and criticize the contemporary scientific conclusions related to indications, the usage methods, the advantages and disadvantages of the PMCs, used in the treatment protocol in pediatric dentistry. The subject of the analysis is 64 english language papers, published in the period from 1966 to 2...

  3. Laboratory fire behavior measurements of chaparral crown fire

    Science.gov (United States)

    C. Sanpakit; S. Omodan; D. Weise; M Princevac

    2015-01-01

    In 2013, there was an estimated 9,900 wildland fires that claimed more than 577,000 acres of land. That same year, about 542 prescribed fires were used to treat 48,554 acres by several agencies in California. Being able to understand fires using laboratory models can better prepare individuals to combat or use fires. Our research focused on chaparral crown fires....

  4. Evaluating the Performance of High-Altitude Aerial Image-Based Digital Surface Models in Detecting Individual Tree Crowns in Mature Boreal Forests

    Directory of Open Access Journals (Sweden)

    Topi Tanhuanpää

    2016-07-01

    Full Text Available Height models based on high-altitude aerial images provide a low-cost means of generating detailed 3D models of the forest canopy. In this study, the performance of these height models in the detection of individual trees was evaluated in a commercially managed boreal forest. Airborne digital stereo imagery (DSI was captured from a flight altitude of 5 km with a ground sample distance of 50 cm and corresponds to regular national topographic airborne data capture programs operated in many countries. Tree tops were detected from smoothed canopy height models (CHM using watershed segmentation. The relative amount of detected trees varied between 26% and 140%, and the RMSE of plot-level arithmetic mean height between 2.2 m and 3.1 m. Both the dominant tree species and the filter used for smoothing affected the results. Even though the spatial resolution of DSI-based CHM was sufficient, detecting individual trees from the data proved to be demanding because of the shading effect of the dominant trees and the limited amount of data from lower canopy levels and near the ground.

  5. Fullerene-C60 and crown ether doped on C60 sensors for high sensitive detection of alkali and alkaline earth cations

    Science.gov (United States)

    Zaghmarzi, Fatemeh Alipour; Zahedi, Mansour; Mola, Adeleh; Abedini, Saboora; Arshadi, Sattar; Ahmadzadeh, Saeed; Etminan, Nazanin; Younesi, Omran; Rahmanifar, Elham; Yoosefian, Mehdi

    2017-03-01

    Fullerenes are effective acceptor components with high electron affinity for charge transfer. The significant influences of chemical adsorption of the cations on the electrical sensitivity of pristine C60 and 15-(C2H4O)5/C60 nanocages could be the basis of new generation of electronic sensor design. The density functional theory calculation for alkali and alkaline earth cations detection by pristine C60 and 15-(C2H4O)5/C60 nanocages are considered at B3LYP level of theory with 6-31 G(d) basis set. The quantum theory of atoms in molecules analysis have been performed to understand the nature of intermolecular interactions between the cations and nanocages. Also, the natural bond orbital analysis have been performed to assess the intermolecular interactions in detail. Furthermore, the frontier molecular orbital, energy gap, work function, electronegativity, number of transferred electron (∆N), dipole moment as well as the related chemical hardness and softness are investigated and calculated in this study. The results show that the adsorption of cations (M=Na+, K+, Mg2+ and Ca2+) are exothermic and the binding energy in pristine C60 nanocage and 15-(C2H4O)5/C60 increases with respect to the cations charge. The results also denote a decrease in the energy gap and an increase in the electrical conductivity upon the adsorption process. In order to validate the obtained results, the density of state calculations are employed and presented in the end as well.

  6. The influence of cervical finish line, internal relief, and cement type on the cervical adaptation of metal crowns

    NARCIS (Netherlands)

    Bottino, Marco Antonio; Valandro, Luiz Felipe; Buso, Leondardo; Oezcan, Mutlu

    2007-01-01

    Objective: The aim of this investigation was to evaluate the cervical adaptation of metal crowns under several conditions, namely (1) variations in the cervical finish line of the preparation, (2) application of internal relief inside the crowns, and (3) cementation using different luting materials.

  7. Severe obesity and high blood pressure among children, Philadelphia health centers, 2010.

    Science.gov (United States)

    Nguyen, John V; Robbins, Jessica M; Houck, Kevin L; Nobis, Elizabeth A; Inman, Katelyn A; Khan, Khudsiya S; Robbins, Susan W

    2014-04-01

    Child obesity is a major health problem particularly affecting disadvantaged population groups. Severe obesity carries additional health risks for children. In the context of the childhood obesity epidemic, high blood pressure among children is of increasing concern. Chart reviews were carried out to examine the prevalence of severe obesity and its association with high blood pressure measurements among randomly selected patients aged 3 to 17 years who had well-child care visits at 8 public community health centers during 2010. A majority of the 691 patients reviewed were African American (58%); an additional 16% were Hispanic. The prevalence of severe obesity was 7.7% (95% confidence interval = 5.8% to 9.9%) and the prevalence of high blood pressure measurements was 17.5% (95% confidence interval = 14.8% to 20.6%). Patients who were severely obese were more than twice as likely as other children to have high blood pressure values. Severe obesity is associated with substantially increased frequency of high blood pressure measurements in children, and should be investigated further as a potential marker for hypertension in children. Primary care providers should be prepared to diagnose and treat hypertension in severely obese children.

  8. The types and severity of high myopic maculopathy in Chinese patients.

    Science.gov (United States)

    Chen, Hui; Wen, Feng; Li, Haitao; Zuo, Chengguo; Zhang, Xiongze; Huang, Shizhou; Luo, Guangwei

    2012-01-01

    To describe the severity and morphological features of high myopic maculopathy in Chinese patients and to evaluate their association with age, refractive error and visual acuity. Six hundred and four eyes of 337 patients (ages 8-88 years) with high myopia (refractive error ≤ -6.0 D) presenting to the Zhongshan Ophthalmic Center were studied retrospectively. All patients underwent an ophthalmological examination including digital colour fundus photography. Fundus fluorescein angiography was performed in 251 patients (443 eyes) and indocyanine green angiography was performed in 35 patients (63 eyes). The type and severity of myopic degeneration were categorized in each eye. Risk factors associated with high myopic maculopathy were evaluated using General Estimating Equation models. Two hundred and fifty-one patients (443 eyes) presented with maculopathy in this study. The most common subtype of high myopic maculopathy was lacquer cracks (prevalence 29.1%). The most commonly observed degree was M(3) (choroidal pallor and tessellation, with posterior staphyloma and lacquer cracks). Older age was significantly associated with diffuse chorioretinal atrophy (p = 0.024), patchy chorioretinal atrophy (p maculopathy: tessellated fundus (p = 0.001), lacquer cracks (p maculopathy. There was no gender difference in the type and severity of myopic maculopathy. Age and refractive error are important risk factors playing different roles in the development of distinct subtypes and varying severities of high myopic maculopathy. Visual acuity is significantly associated with various subtypes and the severity of high myopic maculopathy. Ophthalmic & Physiological Optics © 2011 The College of Optometrists.

  9. Bonded resin composite strip crowns for primary incisors: clinical tips for a successful outcome.

    Science.gov (United States)

    Kupietzky, Ari

    2002-01-01

    The bonded resin composite strip crown is perhaps the most esthetic of all the restorations available to the clinician for the treatment of severely decayed primary incisors. However, strip crowns are also the most technique-sensitive and may be difficult to place. The purpose of this step-by-step technique article is to present some simple clinical tips to assist the clinician in achieving an esthetic and superior outcome.

  10. Marginal Strength of Collarless Metal Ceramic Crown

    Directory of Open Access Journals (Sweden)

    Sikka Swati

    2010-01-01

    fracture strength at margins of metal ceramic crowns cemented to metal tooth analogs. Crowns evaluated with different marginal configurations, shoulder and shoulder bevel with 0 mm, 0.5 mm, 1 mm, and 1.5 mm, were selected. Methods. Maxillary right canine typhodont tooth was prepared to receive a metal ceramic crown with shoulder margin. This was duplicated to get 20 metal teeth analogs. Then the same tooth was reprepared to get shoulder bevel configuration. These crowns were then cemented onmetal teeth analogs and tested for fracture strength atmargin on an Instron testing machine. A progressive compressive load was applied using 6.3 mm diameter rod with crosshead speed of 2.5 mm per minute. Statisticaly analysis was performed with ANOVA, Student's “t” test and “f” test. Results. The fracture strength of collarless metal ceramic crowns under study exceeded the normal biting force. Therefore it can be suggested that collarless metal ceramic crowns with shoulder or shoulder bevel margins up to 1.5 mm framework reduction may be indicated for anteriormetal ceramic restorations. Significance. k Collarless metal ceramic crowns have proved to be successful for anterior fixed restorations. Hence, it may be subjected to more clinical trials.

  11. Parental satisfaction with preveneered stainless steel crowns for primary anterior teeth.

    Science.gov (United States)

    Champagne, Cariann; Waggoner, William; Ditmyer, Marcia; Casamassimo, Paul S; MacLean, Jeanette

    2007-01-01

    The purpose of this study was to evaluate parental satisfaction with preveneered stainless steel crowns placed on their child. A questionnaire using a 5-point Likert-type scale was administered by a trained assistant to a convenience sample of 58 parents at recall of their child at least 6 months after placement of preveneered stainless steel crowns (PVSSCs; NuSmile). The questionnaire asked about: (1) durability; (2) color; (3) size; and (4) shape. Fifty-eight children ranged in age from 18 months to 12 years were approached for participation. Crowns were placed by pediatric dental residents or private practice pediatric dentists. Fifty-four of 58 parent questionnaires were usable. The average age of the children was 5 years, 2 months at recall. The children had crowns present an overage of 13 months at evaluation. Overall, parental acceptance of NuSmile PVSSCs was very high at 93% (N=50). Parents were most satisfied with the crown's: (1) size (N=52; 97%); (2) shape (N=51; 94%); (3) shade and retention (N=48; 89%); (4) metal visibility (N=40; 74%); and (5) durability (N=38; 70%). Forty-three parents (80%) stated that their children were satisfied with the crowns. Parent satisfaction with the NuSmile preveneered stainless steel crowns was very high.

  12. Monolithic CAD/CAM lithium disilicate versus veneered Y-TZP crowns: comparison of failure modes and reliability after fatigue.

    Science.gov (United States)

    Guess, Petra C; Zavanelli, Ricardo A; Silva, Nelson R F A; Bonfante, Estevam A; Coelho, Paulo G; Thompson, Van P

    2010-01-01

    The aim of this research was to evaluate the fatigue behavior and reliability of monolithic computer-aided design/computer-assisted manufacture (CAD/CAM) lithium disilicate and hand-layer-veneered zirconia all-ceramic crowns. A CAD-based mandibular molar crown preparation, fabricated using rapid prototyping, served as the master die. Fully anatomically shaped monolithic lithium disilicate crowns (IPS e.max CAD, n = 19) and hand-layer-veneered zirconia-based crowns (IPS e.max ZirCAD/Ceram, n = 21) were designed and milled using a CAD/CAM system. Crowns were cemented on aged dentinlike composite dies with resin cement. Crowns were exposed to mouth-motion fatigue by sliding a WC-indenter (r = 3.18 mm) 0.7 mm lingually down the distobuccal cusp using three different step-stress profiles until failure occurred. Failure was designated as a large chip or fracture through the crown. If no failures occurred at high loads (> 900 N), the test method was changed to staircase r ratio fatigue. Stress level probability curves and reliability were calculated. Hand-layer-veneered zirconia crowns revealed veneer chipping and had a reliability of monolithic lithium disilicate crowns failed during step-stress mouth-motion fatigue (180,000 cycles, 900 N). CAD/CAM lithium disilicate crowns also survived r ratio fatigue (1,000,000 cycles, 100 to 1,000 N). There appears to be a threshold for damage/bulk fracture for the lithium disilicate ceramic in the range of 1,100 to 1,200 N. Based on present fatigue findings, the application of CAD/CAM lithium disilicate ceramic in a monolithic/fully anatomical configuration resulted in fatigue-resistant crowns, whereas hand-layer-veneered zirconia crowns revealed a high susceptibility to mouth-motion cyclic loading with early veneer failures.

  13. Distribution and prevalence of crown rot pathogens affecting wheat crops in southern Chile

    Directory of Open Access Journals (Sweden)

    Ernesto Moya-Elizondo

    2015-03-01

    Full Text Available Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L. crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W and Purranque (40°50'30" S; 73°22'03" W. Severity of crown rot disease was determined through visual assessment of the first internode of 20 tillers obtained from each field. Incidence of crown rot pathogens per field was determined by plating the 20 tillers on Petri plates with 20% potato dextrose agar amended with lactic acid (aPDA medium. Resulting fungal colonies from monoxenic culture were identified by morphological or molecular-assisted identification. Severity of crown rot varied between 11.3% and 80% for individual fields. Culture plate analysis showed 72.2% of stems were infected with some fungus. Fusarium avenaceum, F. graminearum, and F. culmorum, pathogens associated with Fusarium crown rot disease were isolated from 13.5% of tillers. Gaeumannomyces graminis, causal agent of take-all disease in cereals, was isolated from 11.1% of culms. Phaeosphaeria sp., an endophyte and possibly a non-pathogenic fungus, was isolated from 13.9% of tillers. Pathogenic fungi such as Rhizoctonia spp. and Microdochium nivale, other saprophyte, and several unidentified non-sporulating fungi were isolated at frequencies lower than 3% of the total. Fusarium crown rot and take-all were the most prevalent and distributed crown rot diseases present in wheat crops in southern Chile.

  14. Internal fit evaluation of crowns prepared using a new dental crown fabrication technique: laser-sintered Co-Cr crowns.

    Science.gov (United States)

    Ucar, Yurdanur; Akova, Tolga; Akyil, Musa S; Brantley, William A

    2009-10-01

    Difficulties encountered during casting of base metal dental alloys limit their use. Application of these alloys might be enhanced if new techniques are used. The purpose of this study was to compare the internal fit of laser-sintered Co-Cr alloy crowns with base metal restorations prepared from another Co-Cr alloy and a Ni-Cr alloy using conventional casting techniques. Internal fit of laser-sintered Co-Cr crowns was compared with the fit of conventionally cast Ni-Cr and Co-Cr alloy crowns. Twelve crown-shaped specimens were prepared on a stainless steel die representing a prepared maxillary right central incisor for each group. Fit of crowns was evaluated using 2 different techniques: (1) weighing the light-body addition silicone that simulated a cement material, and (2) measuring the internal gap width on a die for longitudinally sectioned specimens. One-way ANOVA followed by Tukey multiple comparison test was used for statistical analysis (alpha=.05). Significantly higher mean (SD) light-body silicone weights (Pcrowns. However, no significant difference was found among the 3 alloy groups evaluated for the internal gap width of sectioned crown specimens.

  15. Relationships of Chamaecyparis formosensis crown shape and parameters with thinning intensity and age

    Directory of Open Access Journals (Sweden)

    Tian-Ming Yen

    2015-12-01

    Full Text Available Taiwan red cypress (Chamaecyparis formosensis Matsum is an indigenousand important cypress conifer with a broad area of natural forests and plantations in Taiwan. Because of the high economic value and multiple uses of the species, numerous researchers have studied its growth and yield within plantation forests. However, few studies have examined how the crown characteristics of the tree respond to different thinning regimes, particularly in the long run. The crown is a dominant outline of aboveground component of a tree that can sensitively reflect competitions from trees located nearby. This study evaluated the crown form of Taiwan red cypress at three different growth stages with different thinning intensities over 20 years. The study began in 1982, when the three plantations examined were aged 7, 15, and 21 years, and when thinning treatments began. In 2002, crown form parameters (CFPs and crown profile equations (CPEs were used to analyze the thinning effects at the tree level. Two-way analysis of variance (ANOVA revealed that age class influenced most CFPs and that thinning treatments influenced all CFPs, indicating that both factors could simultaneously affect the CFPs. Moreover, the CPEs fit the observed data well for all age classes, demonstrating that the equation had a high capacity for predicting crown form. The CPEs were used to determine the mean crown shape profile for each thinning treatment and age class. According to the mean crown profile predicted by CPEs, we found that crown length and width increased with thinning intensity for all aged trees, especially after a heavy thinning treatment.

  16. Clinical study on high concentrations of sodium hyaluronate eye drops for moderate to severe dry eye

    OpenAIRE

    Yu-Jing Tian; Qin Zhang

    2014-01-01

    AIM: To observe the efficacy of high concentrations of sodium hyaluronate(3g/L SH)for moderate to severe dry eye. METHODS: Forty moderate to severe dry eye patients were included in the study according to the diagnosis criteria and randomized into two groups. The patients of the trial group received topical administration of high concentration sodium hyaluronate(3g/L), and those of the control group received sodium hyaluronate(1g/L)plus recombinant human epidermal growth factor. The dry eye s...

  17. Fracture resistance of zirconia-composite veneered crowns in comparison with zirconia-porcelain crowns.

    OpenAIRE

    Alsadon, O.; Patrick, D.; Johnson, A.; Pollington, S.; Wood, D.

    2017-01-01

    The objectives were to evaluate the fracture resistance and stress concentration in zirconia/composite veneered crowns in comparison to zirconia/porcelain crowns using occlusal fracture resistance and by stress analysis using finite element analysis method. Zirconia substructures were divided into two groups based on the veneering material. A static load was applied occlusally using a ball indenter and the load to fracture was recorded in Newtons (N). The same crown design was used to create ...

  18. Crown-rise and crown-length dynamics: applications to loblolly pine

    Science.gov (United States)

    Harry T. Valentine; Ralph L. Amateis; Jeffrey H. Gove; Annikki. Makela

    2013-01-01

    The original crown-rise model estimates the average height of a crown-base in an even-aged mono-species stand of trees. We have elaborated this model to reduce bias and prediction error, and to also provide crown-base estimates for individual trees. Results for the latter agree with a theory of branch death based on resource availability and allocation.We use the...

  19. Success of Hall technique crowns questioned.

    Science.gov (United States)

    Nainar, S M Hashim

    2012-01-01

    Hall technique is a method of providing stainless steel crowns for primary molars without tooth preparation and requires no local anesthesia. Literature review showed inconclusive evidence and therefore this technique should not be used in clinical practice.

  20. Wear and repair of stainless steel crowns

    National Research Council Canada - National Science Library

    Yilmaz, Y; Kara, N Belduz; Yilmaz, A; Sahin, H

    2011-01-01

    The purpose of this study was to determine the wear of stainless steel crowns (SSCs) in children, and compare the extent of microleakage in SSCs that had been repaired using either a cermet glass-ionomer cement...

  1. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities...

  2. A clinical study evaluating success of 2 commercially available preveneered primary molar stainless steel crowns.

    Science.gov (United States)

    Leith, Rona; O'Connell, Anne C

    2011-01-01

    To evaluate the success of posterior NuSmile(®) and Kinder™Krown and to determine the level of parental satisfaction with this treatment option. Forty-eight crowns were placed in 18 children with a mean age of 5 years. A split mouth design was used. Each participant randomly received each crown type on 2 or 4 pair matched molars. Two trained operators completed all treatments. Two additional trained and calibrated clinicians blindly re-evaluated crowns according to specified variables. A visual analogue scale was used to determine parental satisfaction. Examiner reliability was determined by Cohen's kappa scores and results were analysed statistically using Fisher's exact test. All crowns were retained after 12 months with no statistical difference in the clinical and radiographic success of posterior NuSmile(®) and Kinder™Krowns. Overall success was high with 81% of facings intact and 83% free of gingival inflammation after 12 months. Radiographically, 81% were successful. Veneer facing wear was significantly more likely to occur with opposing crowns (P=.02). Parental satisfaction was excellent with a mean score of 9.3 out of 10. These crowns combine the durability of conventional stainless steel crowns with improved esthetics and are proposed as a suitable alternative where esthetic demand is increased.

  3. Early complications and short-term failures of zirconia single crowns and partial fixed dental prostheses.

    Science.gov (United States)

    Pihlaja, Juha; Näpänkangas, Ritva; Raustia, Aune

    2014-10-01

    Ceramic single crowns fabricated from newer materials, especially zirconia, have shown relatively high survival rates. However, early reversible complications may increase the risk of an irreversible failure later. The purpose of the study was to evaluate the early complications and short-term failures of zirconia single crowns and partial fixed dental prostheses (FDPs) made by predoctoral dental students. Data were collected from the patient records. Altogether, 264 zirconia single crowns and 120 FDPs (342 abutments and 190 pontics) were fabricated for 173 patients between 2007 and 2010. Early complications were recorded during the prosthetic treatment phase, and short-term failures were recorded during the first year in use. The most frequent early complications were localized gingival irritation (1.9% of single crowns and 2.5% of FDP) and postoperative tooth sensitivity (0.4% of single crowns and 3.3% of FDPs). Pulp exposure during preparation was recorded in 3 abutment teeth of the FDPs. The most frequent short-term failure was chipping of the veneering porcelain (0.8% for single crowns, 0.8% for FDPs). One crown lost cementation because of poor retention (0.4%), and 2 FDPs failed because of framework fractures (1.7%). The most frequent early complications were localized gingival irritation and postoperative tooth sensitivity, and the most frequent short-term failure was chipping of the veneering porcelain. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  4. 4-Bromoanilinium perchlorate 18-crown-6 clathrate

    Directory of Open Access Journals (Sweden)

    Min Guo

    2010-11-01

    Full Text Available The reaction of 4-bromoaniline, 18-crown-6, and perchloric acid in methanol yields the title compound, C6H7BrN+·ClO4−·C12H24O6, in which the protonated –NH3+ group forms three bifurcated N—H...O hydrogen bonds to the O atoms of the crown ether.

  5. Severe encephalopathy after high-dose chemotherapy with autologous stem cell support for brain tumours.

    Science.gov (United States)

    van den Berkmortel, F; Gidding, C; De Kanter, M; Punt, C J A

    2006-01-01

    Recurrent medulloblastoma carries a poor prognosis. Long-term survival has been obtained with high-dose chemotherapy with autologous stem cell transplantation and secondary irradiation. A 21-year-old woman with recurrent medulloblastoma after previous chemotherapy and radiotherapy is presented. The patient was treated with high-dose chemotherapy and autologous stem cell transplantation. She developed a severe treatment-related encephalopathy which affected her quality of life and neurocognitive functioning for the rest of her life. Possible causative factors are discussed and central nervous system toxicity by high-dose chemotherapy in brain tumour patients is reviewed. Case reports on severe central nervous system toxicity have been reported, but data from prospective studies on neurocognitive functioning are not available. These data strongly support a systematic long-term follow-up of brain tumour patients treated with high-dose chemotherapy with emphasis on neurocognitive function tests.

  6. Experimental and numerical modeling of shrub crown fire initiation

    Science.gov (United States)

    Watcharapong Tachajapong; Jesse Lozano; Shakar Mahalingam; Xiangyang Zhou; David Weise

    2009-01-01

    The transition of fire from dry surface fuels to wet shrub crown fuels was studied using laboratory experiments and a simple physical model to gain a better understanding of the transition process. In the experiments, we investigated the effects of varying vertical distances between surface and crown fuels (crown base height), and of the wind speed on crown fire...

  7. Infrared Spectroscopy of Divalent Zinc and Cadmium Crown Ether Systems

    NARCIS (Netherlands)

    Cooper, T. E.; Carl, D. R.; Oomens, J.; Steill, J. D.; Armentrout, P. B.

    2011-01-01

    The gas-phase structures of transition-metal dication (Zn2+ and Cd2+) complexes with varying sized crown ethers, 12-crown-4 (12c4), 15-crown-5 (15c5), and 18-crown-6 (18c6), are investigated using infrared multiple photon dissociation (IRMPD) spectroscopy and quantum mechanical calculations. The

  8. A numerical rating system for crown classes of southern hardwoods

    Science.gov (United States)

    James S. Meadows; E.C. Burkhardt; Robert L. Johnson; John D. Hodges

    2001-01-01

    A numerical rating system to delineate crown classes of southern hardwoods is described. The system is based on four criteria: (1) amount of direct sunlight from above, (2) amount of direct sunlight from the sides, (3) crown balance, and (4) relative crown size. The total point value assigned places the tree within one of the four crown classes. The rating system can...

  9. Investigating the Dynamics of Wandoo Crown Decline with Time Series Landsat Imagery

    Science.gov (United States)

    Zdunic, K.; Behn, G.; van Dongen, R.

    2012-08-01

    In the forests of south west Western Australia dramatic declines in tree health have been observed in recent years. The species Eucalyptus wando has exhibited loss of crown foliage in increasing stages of severity; this condition is referred to as wandoo crown decline and can lead to death. Determining the extent and timing of these declines is difficult on the ground due to the large distribution of E. wandoo and the observation of tree declines at a range of locations and dates over the last 40 years. Understanding the distribution, severity and timing of these declines is essential to the identification of the causes of these impacts. Investigation of time series Landsat imagery can inform on locations of crown foliage loss and the time periods these losses occurred in. Applying a vegetation index to a 20 year sequence of imagery enabled periods of decline to be identified. Employment of trend analysis of four date time series demonstrated the dynamics of wandoo crown cover. Comparisons of periods of decline with the variations of cover density over the entire image sequence facilitated the identification of possible locations and timing of wandoo crown decline impacts. Changes in crown cover observed by the imagery analysis were compared to field surveys.

  10. Epidemiology of severe injuries among United States high school athletes: 2005-2007.

    Science.gov (United States)

    Darrow, Cory J; Collins, Christy L; Yard, Ellen E; Comstock, R Dawn

    2009-09-01

    Over 7 million students participate in high school athletics annually. Despite numerous health benefits, high school athletes are at risk for injury. Severe injury rates and patterns differ by gender and type of exposure. Study Design Descriptive epidemiology study. Sports-related injury data were collected during the 2005-2007 academic years from 100 nationally representative United States high schools via RIO (Reporting Information Online). Severe injury was defined as any injury that resulted in the loss of more than 21 days of sports participation. Participating certified athletic trainers (ATCs) reported 1378 severe injuries during 3 550 141 athlete-exposures (0.39 severe injuries per 1000 athletic exposures). Football had the highest severe injury rate (0.69), followed by wrestling (0.52), girls' basketball (0.34), and girls' soccer (0.33). The rate in all boys' sports (0.45) was higher than all girls' sports (0.26) (rate ratio [RR], 1.74; 95% confidence interval [CI], 1.54-1.98; P sports (soccer, basketball, and baseball/softball), girls sustained a higher severe injury rate (0.29) than boys (0.23) (RR, 1.28; 95% CI, 1.08-1.52; P = .006). More specifically, girls' basketball had a higher rate (0.34) than boys' basketball (0.24) (RR, 1.43; 95% CI, 1.10-1.86; P = .009). Differences between boys' and girls' soccer and baseball/softball were not statistically significant. The severe injury rate was greater in competition (0.79) than practice (0.24) (RR, 3.30; 95% CI, 2.97-3.67; P sports injuries, 0.3% resulted in medical disqualification for the athletes' career, and an additional 56.8% resulted in medical disqualification for the entire season. One in 4 (28.3%) severe injuries required surgery, with over half (53.9%) being knee surgeries. Severe injury rates and patterns varied by sport, gender, and type of exposure. Because severe injuries negatively affect athletes' health and often place an increased burden on the health care system, future research should

  11. Does Visual Performance Influence Head Impact Severity Among High School Football Athletes?

    Science.gov (United States)

    Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W

    2015-11-01

    To compare the odds of sustaining moderate and severe head impacts, rather than mild, between high school football players with high and low visual performance. Prospective quasi-experimental. Clinical Research Center/On-field. Thirty-seven high school varsity football players. Athletes completed the Nike SPARQ Sensory Station visual assessment before the season. Head impact biomechanics were captured at all practices and games using the Head Impact Telemetry System. Each player was classified as either a high or low performer using a median split for each of the following visual performance measures: visual clarity, contrast sensitivity, depth perception, near-far quickness, target capture, perception span, eye-hand coordination, go/no go, and reaction time. We computed the odds of sustaining moderate and severe head impacts against the reference odds of sustaining mild head impacts across groups of high and low performers for each of the visual performance measures. Players with better near-far quickness had increased odds of sustaining moderate [odds ratios (ORs), 1.27; 95% confidence intervals (CIs), 1.04-1.56] and severe head impacts (OR, 1.45; 95% CI, 1.05-2.01) as measured by Head Impact Technology severity profile. High and low performers were at equal odds on all other measures. Better visual performance did not reduce the odds of sustaining higher magnitude head impacts. Visual performance may play less of a role than expected for protecting against higher magnitude head impacts among high school football players. Further research is needed to determine whether visual performance influences concussion risk. Based on our results, we do not recommend using visual training programs at the high school level for the purpose of reducing the odds of sustaining higher magnitude head impacts.

  12. Stress corrosion cracking of several high strength ferrous and nickel alloys

    Science.gov (United States)

    Nelson, E. E.

    1971-01-01

    The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

  13. High Levels of Methylarginines Were Associated With Increased Mortality in Patients With Severe Sepsis

    DEFF Research Database (Denmark)

    Mortensen, Karoline Myglegard; Itenov, Theis Skovsgaard; Haase, Nicolai

    2016-01-01

    . We investigated if high-plasma levels of ADMA, SDMA, and arginine/ADMA ratio were associated with 90-day mortality in patients with severe sepsis or septic shock. Methods: We included 267 adult patients admitted to intensive care unit with severe sepsis or septic shock. The patients had previously...... been included in the randomized controlled trial “Scandinavian Starch for Severe Sepsis and Septic Shock (6S).” ADMA, SDMA, and arginine/ADMA ratio were measured in plasma. The risk of death within 90 days was estimated in multivariate Cox regression analyses adjusted for gender, age >=65 years, major...... in patients with severe sepsis or septic shock. Interfering with the methylarginine-NO systems may be a novel target in these patients....

  14. Preformed crowns for decayed primary molar teeth.

    Science.gov (United States)

    Innes, Nicola P T; Ricketts, David; Chong, Lee Yee; Keightley, Alexander J; Lamont, Thomas; Santamaria, Ruth M

    2015-12-31

    Crowns for primary molars are preformed and come in a variety of sizes and materials to be placed over decayed or developmentally defective teeth. They can be made completely of stainless steel (know as 'preformed metal crowns' or PMCs), or to give better aesthetics, may be made of stainless steel with a white veneer cover or made wholly of a white ceramic material. In most cases, teeth are trimmed for the crowns to be fitted conventionally using a local anaesthetic. However, in the case of the Hall Technique, PMCs are pushed over the tooth with no local anaesthetic, carious tissue removal or tooth preparation. Crowns are recommended for restoring primary molar teeth that have had a pulp treatment, are very decayed or are badly broken down. However, few dental practitioners use them in clinical practice. This review updates the original review published in 2007. Primary objectiveTo evaluate the clinical effectiveness and safety of all types of preformed crowns for restoring primary teeth compared with conventional filling materials (such as amalgam, composite, glass ionomer, resin modified glass ionomer and compomers), other types of crowns or methods of crown placement, non-restorative caries treatment or no treatment. Secondary objectiveTo explore whether the extent of decay has an effect on the clinical outcome of primary teeth restored with all types of preformed crowns compared with those restored with conventional filling materials. We searched the following electronic databases: Cochrane Oral Health Group Trials Register (to 21 January 2015), Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library, 2014, Issue 12), MEDLINE via Ovid (1946 to 21 January 2015) and EMBASE via Ovid (1980 to 21 January 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing trials and Open Grey for grey literature (to

  15. Extreme fire severity patterns in topographic, convective and wind-driven historical wildfires of Mediterranean pine forests.

    Directory of Open Access Journals (Sweden)

    Judit Lecina-Diaz

    Full Text Available Crown fires associated with extreme fire severity are extremely difficult to control. We have assessed fire severity using differenced Normalized Burn Ratio (dNBR from Landsat imagery in 15 historical wildfires of Pinus halepensis Mill. We have considered a wide range of innovative topographic, fuel and fire behavior variables with the purposes of (1 determining the variables that influence fire severity patterns among fires (considering the 15 wildfires together and (2 ascertaining whether different variables affect extreme fire severity within the three fire types (topographic, convective and wind-driven fires. The among-fires analysis showed that fires in less arid climates and with steeper slopes had more extreme severity. In less arid conditions there was more crown fuel accumulation and closer forest structures, promoting high vertical and horizontal fuel continuity and extreme fire severity. The analyses carried out for each fire separately (within fires showed more extreme fire severity in areas in northern aspects, with steeper slopes, with high crown biomass and in climates with more water availability. In northern aspects solar radiation was lower and fuels had less water limitation to growth which, combined with steeper slopes, produced more extreme severity. In topographic fires there was more extreme severity in northern aspects with steeper slopes and in areas with more water availability and high crown biomass; in convection-dominated fires there was also more extreme fire severity in northern aspects with high biomass; while in wind-driven fires there was only a slight interaction between biomass and water availability. This latter pattern could be related to the fact that wind-driven fires spread with high wind speed, which could have minimized the effect of other variables. In the future, and as a consequence of climate change, new zones with high crown biomass accumulated in non-common drought areas will be available to burn

  16. Extreme Fire Severity Patterns in Topographic, Convective and Wind-Driven Historical Wildfires of Mediterranean Pine Forests

    Science.gov (United States)

    Lecina-Diaz, Judit; Alvarez, Albert; Retana, Javier

    2014-01-01

    Crown fires associated with extreme fire severity are extremely difficult to control. We have assessed fire severity using differenced Normalized Burn Ratio (dNBR) from Landsat imagery in 15 historical wildfires of Pinus halepensis Mill. We have considered a wide range of innovative topographic, fuel and fire behavior variables with the purposes of (1) determining the variables that influence fire severity patterns among fires (considering the 15 wildfires together) and (2) ascertaining whether different variables affect extreme fire severity within the three fire types (topographic, convective and wind-driven fires). The among-fires analysis showed that fires in less arid climates and with steeper slopes had more extreme severity. In less arid conditions there was more crown fuel accumulation and closer forest structures, promoting high vertical and horizontal fuel continuity and extreme fire severity. The analyses carried out for each fire separately (within fires) showed more extreme fire severity in areas in northern aspects, with steeper slopes, with high crown biomass and in climates with more water availability. In northern aspects solar radiation was lower and fuels had less water limitation to growth which, combined with steeper slopes, produced more extreme severity. In topographic fires there was more extreme severity in northern aspects with steeper slopes and in areas with more water availability and high crown biomass; in convection-dominated fires there was also more extreme fire severity in northern aspects with high biomass; while in wind-driven fires there was only a slight interaction between biomass and water availability. This latter pattern could be related to the fact that wind-driven fires spread with high wind speed, which could have minimized the effect of other variables. In the future, and as a consequence of climate change, new zones with high crown biomass accumulated in non-common drought areas will be available to burn as extreme

  17. Extreme fire severity patterns in topographic, convective and wind-driven historical wildfires of Mediterranean pine forests.

    Science.gov (United States)

    Lecina-Diaz, Judit; Alvarez, Albert; Retana, Javier

    2014-01-01

    Crown fires associated with extreme fire severity are extremely difficult to control. We have assessed fire severity using differenced Normalized Burn Ratio (dNBR) from Landsat imagery in 15 historical wildfires of Pinus halepensis Mill. We have considered a wide range of innovative topographic, fuel and fire behavior variables with the purposes of (1) determining the variables that influence fire severity patterns among fires (considering the 15 wildfires together) and (2) ascertaining whether different variables affect extreme fire severity within the three fire types (topographic, convective and wind-driven fires). The among-fires analysis showed that fires in less arid climates and with steeper slopes had more extreme severity. In less arid conditions there was more crown fuel accumulation and closer forest structures, promoting high vertical and horizontal fuel continuity and extreme fire severity. The analyses carried out for each fire separately (within fires) showed more extreme fire severity in areas in northern aspects, with steeper slopes, with high crown biomass and in climates with more water availability. In northern aspects solar radiation was lower and fuels had less water limitation to growth which, combined with steeper slopes, produced more extreme severity. In topographic fires there was more extreme severity in northern aspects with steeper slopes and in areas with more water availability and high crown biomass; in convection-dominated fires there was also more extreme fire severity in northern aspects with high biomass; while in wind-driven fires there was only a slight interaction between biomass and water availability. This latter pattern could be related to the fact that wind-driven fires spread with high wind speed, which could have minimized the effect of other variables. In the future, and as a consequence of climate change, new zones with high crown biomass accumulated in non-common drought areas will be available to burn as extreme

  18. Acacia shrubs respond positively to high severity wildfire: Implications for conservation and fuel hazard management.

    Science.gov (United States)

    Gordon, Christopher E; Price, Owen F; Tasker, Elizabeth M; Denham, Andrew J

    2017-01-01

    High severity wildfires pose threats to human assets, but are also perceived to impact vegetation communities because a small number of species may become dominant immediately after fire. However there are considerable gaps in our knowledge about species-specific responses of plants to different fire severities, and how this influences fuel hazard in the short and long-term. Here we conduct a floristic survey at sites before and two years after a wildfire of unprecedented size and severity in the Warrumbungle National Park (Australia) to explore relationships between post-fire growth of a fire responsive shrub genera (Acacia), total mid-story vegetation cover, fire severity and fuel hazard. We then survey 129 plots surrounding the park to assess relationships between mid-story vegetation cover and time-since-fire. Acacia species richness and cover were 2.3 and 4.3 times greater at plots after than before the fire. However the same common dominant species were present throughout the study. Mid-story vegetation cover was 1.5 times greater after than before the wildfire, and Acacia species contribution to mid-story cover increased from 10 to 40%. Acacia species richness was not affected by fire severity, however strong positive associations were observed between Acacia and total mid-story vegetation cover and severity. Our analysis of mid-story vegetation recovery showed that cover was similarly high between 2 and 30years post-fire, then decreased until 52years. Collectively, our results suggest that Acacia species are extremely resilient to high severity wildfire and drive short to mid-term increases in fuel hazard. Our results are discussed in relation to fire regime management from the twin perspectives of conserving biodiversity and mitigating human losses due to wildfire. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. High Titer and Yields Achieved with Novel, Low-Severity Pretreatment Strategy

    Energy Technology Data Exchange (ETDEWEB)

    2016-03-01

    NREL researchers obtained high concentration sugar syrups in enzymatic hydrolysis that are fermentable to ethanol and other advanced biofuels and intermediate products at high yields. The novel DMR process is simpler and bypasses all severe pretreatment methods, thus reducing the environmental impact. The results are unprecedented. Researchers achieved a high concentration of sugars (230g/L of monomeric sugar and 270 g/L total sugar) and this low toxicity, highly fermentable syrup yielded 86 g/L ethanol (> 90 percent conversion). In addition, the lignin streams from this process can readily be converted to jet or renewable diesel blendstocks through a hydrodeoxygenation step. The NREL-developed, low severity DMR process may potentially replace higher severity chemical pretreatments and associated expensive reactors constructed of exotic alloys with a simpler process, using commercial-scale equipment commonly associated with the pulp and paper industry, to produce high concentration, low toxicity sugar streams and highly reactive lignin streams from non-food renewable biomass for biological and catalytic upgrading to advanced biofuels and chemicals. The simpler DMR process with black liquor recycling could reduce environmental and life-cycle impacts, and repurpose shuttered pulp and paper mills to help revitalize rural economies.

  20. High serum ACE activity predicts severe hypoglycaemia over time in patients with type 1 diabetes

    DEFF Research Database (Denmark)

    Færch, Louise; Pedersen-Bjergaard, Ulrik; Thorsteinsson, Birger

    2011-01-01

    High serum angiotensin-converting enzyme (ACE) activity is associated with increased risk of severe hypoglycaemia (SH) within 1 year in type 1 diabetes. We wanted to find out whether ACE activity is stable over time and predicts SH beyond 1 year, and if gender differences exist in the association...

  1. High serum ACE activity predicts severe hypoglycaemia over time in patients with type 1 diabetes

    DEFF Research Database (Denmark)

    Færch, Louise; Pedersen-Bjergaard, Ulrik; Thorsteinsson, Birger

    2011-01-01

    High serum angiotensin-converting enzyme (ACE) activity is associated with increased risk of severe hypoglycaemia (SH) within 1 year in type 1 diabetes. We wanted to find out whether ACE activity is stable over time and predicts SH beyond 1 year, and if gender differences exist in the association...... between ACE activity and risk of SH....

  2. Efficacy and Social Validity of Peer Network Interventions for High School Students with Severe Disabilities

    Science.gov (United States)

    Asmus, Jennifer M.; Carter, Erik W.; Moss, Colleen K.; Biggs, Elizabeth E.; Bolt, Daniel M.; Born, Tiffany L.; Bottema-Beutel, Kristen; Brock, Matthew E.; Cattey, Gillian N.; Cooney, Molly; Fesperman, Ethan S.; Hochman, Julia M.; Huber, Heartley B.; Lequia, Jenna L.; Lyons, Gregory L.; Vincent, Lori B.; Weir, Katie

    2017-01-01

    This randomized controlled trial examined the efficacy of peer network interventions to improve the social connections of 47 high school students with severe disabilities. School staff invited, trained, and supported 192 peers without disabilities to participate in individualized social groups that met throughout one semester. Compared to…

  3. Comparison of the load at failure of soldered and nonsoldered porcelain-fused-to-metal crowns.

    Science.gov (United States)

    Kang, Min-Sok; Ercoli, Carlo; Galindo, Daniel F; Graser, Gerald N; Moss, Mark E; Tallents, Ross H

    2003-09-01

    The application of solder material to metal frameworks could affect the porcelain-to-metal failure load and possibly compromise the longevity of porcelain-fused-to-metal crowns. This in vitro study assessed the influence of solder on the porcelain failure load between metal and porcelain, using crown-shaped specimens. Forty standardized crown patterns were fabricated on a metal die and cast with noble alloy (Protocol). The specimens were divided into test (soldered, n=20) and control (nonsoldered, n=20) groups. A 2-mm-diameter perforation was produced on the buccal surface of the test specimens, 1.5 mm apical to the junction between occlusal and buccal surfaces. The perforation was repaired with high-fusing white ceramic solder material. All castings were finished with aluminum oxide stones and airborne-particle abraded with 50-microm aluminum oxide at 75 psi of pressure. Two layers each of opaque and dentin porcelain were applied on all specimens. All crowns were subjected to a vertical compressive load with a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. The loading apparatus of the device contacted the buccal cusp only. In both control and test groups, 10 crowns were loaded with a stainless steel pin (phase I) whereas the remaining 10 in each group were loaded with a carbon steel pin (phase II). Means of loads at failure were recorded in each group for each pin type and compared (soldered vs nonsoldered) by use of a t test (alpha=.05). Mean failure load for nonsoldered crowns was 349 +/- 63 kgf in phase I and 228 +/- 49 kgf in phase II. Soldered crowns showed a significantly lower failure load (265 +/- 82 kgf [phase I; Pstandard deviation. Soldered metal-porcelain crown specimens demonstrated a significantly lower load at failure. Within the limits of this study, it was concluded that solder material might negatively affect porcelain-metal crowns.

  4. Long-term clinical performance of esthetic primary molar crowns.

    Science.gov (United States)

    Ram, Diana; Fuks, Anna B; Eidelman, Eliecer

    2003-01-01

    The aim of the study was to report the long-term clinical performance of esthetic primary molar crowns and compare them to that of stainless steel crowns (SSC). Twenty crowns (10 conventional and 10 esthetic) placed in 10 children who had participated in a previously reported study, were assessed again after 4 years. The crowns were evaluated clinically and radiographically according to the following parameters: gingival health, marginal extension, crown adequacy, proper occlusion, proximal contact, chipping of the facing (for esthetic crowns only), and cement removal. At the 4 year evaluation, all the esthetic crowns showed chipping of the facing. No difference was found for marginal extension, occlusion, crown adequacy and periodontal health between SSCs and the esthetic crowns. After 4 years, all the esthetic crowns presented chipping of the facing and, consequently, a very poor esthetic appearance.

  5. THE EFFECT OF ABOVEGROUND COMPETITION ON SPATIAL STRUCTURE AND CROWN SHAPE OF THE DOMINATING CANOPY SPECIES OF FOREST STANDS OF EUROPEAN RUSSIA

    Directory of Open Access Journals (Sweden)

    V. N. Shanin

    2016-12-01

    Full Text Available Background. The most of ecosystem models do not take into account the asymmetry of crowns resulted from the competition between trees. Thus, the objective of the current study is to estimate quantitatively the effect of competition on shape and size of tree crowns. Materials and methods. The study was carried out in mixed and pure spruce, pine and birch stands in the Moscow and Novgorod regions. Mapping of trees was carried out on 14 sample plots of 25×25 m in size. Stem diameter, crown length and crown spread in four cardinal directions were measured for each tree. The relationship between crown size and tree stem size was analysed, as well as spatial distribution of stem bases and centroids of crown projections. Results. We found that crown size and shape is strongly dependent on tree species, its location in stand, and stand density. Pioneer tree species are characterized by relatively narrower crowns with high relative crown base height while the late-successional tree species have relatively wider crowns. The asymmetry of crown projection was shown to be strongly influenced by a tree neighbourhood. We also found that centroids of crown projections are distributed in space more regularly than stem bases. Conclusions. The species-specific features in crown development were shown. The analysis of results confirmed the previously described mechanism of adaptation to competition from neighbouring trees through asymmetric crown expansion in different directions. The relationships derived can be used for development of improved algorithm of simulation of aboveground competition. New procedure will allow us account the influence of a tree neighbourhood on the size and shape of its crown.

  6. Surviving severe traumatic brain injury in Denmark: incidence and predictors of highly specialized rehabilitation

    Directory of Open Access Journals (Sweden)

    Odgaard L

    2015-03-01

    Full Text Available Lene Odgaard,1 Ingrid Poulsen,2 Lars Peter Kammersgaard,2 Søren Paaske Johnsen,3 Jørgen Feldbæk Nielsen,1 1Hammel Neurorehabilitation Center and University Research Clinic, Aarhus University, Aarhus, Denmark; 2Department of Neurorehabilitation, TBI and Research Unit on Brain injury rehabilitation (RUBRIC, Glostrup Hospital, Copenhagen University, Copenhagen, Denmark; 3Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark Purpose: To identify all hospitalized patients surviving severe traumatic brain injury (TBI in Denmark and to compare these patients to TBI patients admitted to highly specialized rehabilitation (HS-rehabilitation. Patients and methods: Patients surviving severe TBI were identified from The Danish National Patient Registry and The Danish Head Trauma Database. Overall incidence rates of surviving severe TBI and incidence rates of admission to HS-rehabilitation after severe TBI were estimated and compared. Patient-related predictors of no admission to HS-rehabilitation among patients surviving severe TBI were identified using multivariable logistic regression. Results: The average incidence rate of surviving severe TBI was 2.3 per 100,000 person years. Incidence rates of HS-rehabilitation were generally stable around 2.0 per 100,000 person years. Overall, 84% of all patients surviving severe TBI were admitted to HS-rehabilitation. Female sex, older age, and non-working status pre-injury were independent predictors of no HS-rehabilitation among patients surviving severe TBI. Conclusion: The incidence rate of hospitalized patients surviving severe TBI was stable in Denmark and the majority of the patients were admitted to HS-rehabilitation. However, potential inequity in access to HS-rehabilitation may still be present despite a health care system based on equal access for all citizens. Keywords: database, health care disparities, registries, validity 

  7. An investigation of crown fuel bulk density effects on the dynamics of crown fire initiation in shrublands

    Science.gov (United States)

    Watcharapong Tachajapong; Jesse Lozano; Shankar Mahalingam; Xiangyang Zhou; David R. Weise

    2008-01-01

    Crown fire initiation is studied by using a simple experimental and detailed physical modeling based on Large Eddy Simulation (LES). Experiments conducted thus far reveal that crown fuel ignition via surface fire occurs when the crown base is within the continuous flame region and does not occur when the crown base is located in the hot plume gas region of the surface...

  8. Comparison of the fracture strengths of metal-ceramic crowns and three ceromer crowns.

    Science.gov (United States)

    Ku, Chul-Whoi; Park, Sang-Won; Yang, Hong-So

    2002-08-01

    The fracture strength of a number of new ceromer systems for the fabrication of anterior fixed partial dentures is unknown. The purpose of this study was to compare the fracture strengths of metal-ceramic crowns and 3 types of ceromer crowns in a simulated anterior tooth preparation. A resin maxillary central incisor analog was prepared with a 5-degree convergence angle and a 90-degree, 1-mm shoulder. The incisal edge was reduced by 2 mm, and the axiogingival and axioincisal line angles were rounded. A mold of this tooth was made with vinyl polysiloxane impression material. Ten wax patterns were made from the mold and cast in a nickel-chromium alloy for the fabrication of metal dies, from which 10 metal-ceramic crowns were fabricated. Ten crowns for each of 3 ceromer systems (Artglass, Sculpture, and Targis) were fabricated from the same metal die. Each crown group was prepared, polymerized, air-particle abraded, and finished in accordance with the specific manufacturer's instructions. All 4 types of finished crowns were luted to the dies and embedded in polymethyl methacrylate resin blocks. Their fracture resistance was tested in a universal testing machine. The load was directed at the incisolingual line angle, at 130 degrees to the long axis of each specimen, until catastrophic failure occurred. A 7-mm-diameter rod was used to load the artificial crowns, with the center of the rod in contact with the crown surfaces. Analysis of variance and Tukey's multiple comparisons test (PMetal-ceramic crowns fractured at significantly higher values than ceromer crowns (1317 vs 602 N, respectively) (Pmetal-ceramic crowns, still exceeded normal occlusal forces.

  9. COMPARSION EFFECTIVENES METHODS REPEIR CROWN TEETH IN DOGS

    OpenAIRE

    CHOOHNO V.S.

    2008-01-01

    Methods of dogs’ crown teeth restoration with using of anchor pin with light curable composite, glass fiber pin with light curable composite, stump crown with prosthetic crown were approved. Their effectiveness was compared. Greater reliability was shown by methods of stump crown with prosthetic crown, when using of which there was no that restoration damage in all cases, but there was no cosmetics effect. Restoration methods with using anchor pin with light curable composite and glass fiber ...

  10. High severity fire in forests of the southwest: Conservation implications. Progress Report August 2005

    Science.gov (United States)

    Haire, Sandra L.

    2006-01-01

    The occurrence of large, severe fires in southwestern ponderosa pine (Pinus ponderosa) forests has resulted in concern that these forests may not persist under such an extreme disturbance regime. In our research, we are examining the outcomes of high-severity fire in ponderosa pine forests and their neighboring communities across an elevational gradient. One goal of our work is to contribute to understanding the resiliency of these systems, but we also want to investigate the conservation values intrinsic to the diverse communities that represent alternative successional trajectories after severe fire. One assumption of our research is that the spatial pattern of a disturbance becomes increasingly important when the disturbance is large and biological legacies are few and sparse. We ask, therefore, what spectrum of plant communities results from high severity fire, and what is their relationship to spatial patterns of severity mapped in early post fire timeframes? Also, do spatial patterns of older burns (1950–80) differ from recent burns (1998–present) in ways that make us expect successional changes years from now to differ from those we observed at our older burn field sites?

  11. CBT for insomnia in patients with high and low depressive symptom severity: adherence and clinical outcomes.

    Science.gov (United States)

    Manber, Rachel; Bernert, Rebecca A; Suh, Sooyeon; Nowakowski, Sara; Siebern, Allison T; Ong, Jason C

    2011-12-15

    To evaluate whether depressive symptom severity leads to poorer response and perceived adherence to cognitive behavioral therapy for insomnia (CBTI) and to examine the impact of CBTI on well-being, depressive symptom severity, and suicidal ideation. Pre- to posttreatment case replication series comparing low depression (LowDep) and high depression (HiDep) groups (based on a cutoff of 14 on the Beck Depression Inventory [BDI]). 127 men and 174 women referred for the treatment of insomnia. Seven sessions of group CBTI. Improvement in the insomnia severity, perceived energy, productivity, self-esteem, other aspects of wellbeing, and overall treatment satisfaction did not differ between the HiDep and LowDep groups (p > 0.14). HiDep patients reported lower adherence to a fixed rise time, restricting time in bed, and changing expectations about sleep (p depressive symptom severity. Thus, the benefits of CBTI extend beyond insomnia and include improvements in non-sleep outcomes, such as overall well-being and depressive symptom severity, including suicidal ideation, among patients with baseline elevations. Results identify aspects of CBTI that may merit additional attention to further improve outcomes among patients with insomnia and elevated depressive symptom severity.

  12. Development of highly reliable power and communication system for essential instruments under severe accidents in NPP

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Bo Hwan; Jang, Gi Chan; Shin, Sung Min; Kang, Hyun Gook; Rim, Chun Taek [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Soo Ill [I and C Group, Korea Hydro and Nuclear Power Co., Ltd, Central Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to 627 .deg. C and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad.

  13. Development of Highly Reliable Power and Communication System for Essential Instruments Under Severe Accidents in NPP

    Directory of Open Access Journals (Sweden)

    Bo Hwan Choi

    2016-10-01

    Full Text Available This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to 627°C and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad.

  14. The Influence of Severe Storm Tracks on High Impact Weather in North America

    Science.gov (United States)

    Berbery, E. Hugo; Lukens, Katherine

    2017-04-01

    The behavior of Northern Hemisphere (NH) severe storm tracks and their influence on high impact winter weather are diagnostically studied using data from the Climate Forecast System Reanalysis (CFSR) and the Global Precipitation Climatology Project (GPCP). In this study high impact weather is represented by strong low-level winds and intense precipitation. Storm tracks are described by isentropic potential vorticity (IPV) maxima within a Lagrangian framework and are found to correspond with those described in previous studies: three storm tracks are identified over the North Pacific and North Atlantic Oceans as well as over the Mediterranean Sea. The cyclogenesis pattern shows that severe storms (the top 14% of all storms) generally develop along the tracks. The cyclolysis pattern reveals that most cyclones dissipate in the eastern North Pacific and western North Atlantic Oceans. Across the NH, the diabatic heating increases where the storm tracks are present, with the larger heating gradients corresponding to high track density regions, i.e., where the majority of storms tend to propagate. Precipitation intensity related to the severe storm tracks is largest where they are strongest, e.g., over the oceans, and along the west coast of North America. Over North America, it is found that severe storms contribute 40-60% of the precipitation produced by all winter storms. The largest increases in low-level wind speeds are found in the storm track regions which are collocated poleward and eastward of the jet stream maxima over the oceans. The winds in the severe storm track regions almost double in speed from the background wind, particularly in the northeastern North Pacific, the northeastern North Atlantic, and leeward of the Rocky Mountains. Leeward of high orography, the winds intensify and flow southeastward across North America toward the North Atlantic Ocean.

  15. High Body Mass Index in Infancy May Predict Severe Obesity in Early Childhood.

    Science.gov (United States)

    Smego, Allison; Woo, Jessica G; Klein, Jillian; Suh, Christina; Bansal, Danesh; Bliss, Sherri; Daniels, Stephen R; Bolling, Christopher; Crimmins, Nancy A

    2017-04-01

    To characterize growth trajectories of children who develop severe obesity by age 6 years and identify clinical thresholds for detection of high-risk children before the onset of obesity. Two lean (body mass index [BMI] 5th to ≤75th percentile) and 2 severely obese (BMI ≥99th percentile) groups were selected from populations treated at pediatric referral and primary care clinics. A population-based cohort was used to validate the utility of identified risk thresholds. Repeated-measures mixed modeling and logistic regression were used for analysis. A total of 783 participants of normal weight and 480 participants with severe obesity were included in the initial study. BMI differed significantly between the severely obese and normal-weight cohorts by age 4 months (P severe obesity by age 6 years (sensitivity, 51%-95%; specificity, 95%). This BMI threshold was validated in a second independent cohort (n = 2649), with a sensitivity of 33%-77% and a specificity of 74%-87%. A BMI ≥85th percentile in infancy increases the risk of severe obesity by age 6 years by 2.5-fold and the risk of clinical obesity by age 6 years by 3-fold. BMI trajectories in children who develop severe obesity by age 6 years differ from those in children who remain at normal weight by age 4-6 months, before the onset of obesity. Infants with a WHO BMI ≥85th percentile are at increased risk for developing severe obesity by age 6 years. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Urban Crowns: crown analysis software to assist in quantifying urban tree benefits

    Science.gov (United States)

    Matthew F. Winn; Sang-Mook Lee Bradley; Philip A. Araman

    2010-01-01

    UrbanCrowns is a Microsoft® Windows®-based computer program developed by the U.S. Forest Service Southern Research Station. The software assists urban forestry professionals, arborists, and community volunteers in assessing and monitoring the crown characteristics of urban trees (both deciduous and coniferous) using a single side-view digital photograph. Program output...

  17. Examining the profile of high-potency cannabis and its association with severity of cannabis dependence.

    Science.gov (United States)

    Freeman, T P; Winstock, A R

    2015-11-01

    Cannabis use is decreasing in England and Wales, while demand for cannabis treatment in addiction services continues to rise. This could be partly due to an increased availability of high-potency cannabis. Adults residing in the UK were questioned about their drug use, including three types of cannabis (high potency: skunk; low potency: other grass, resin). Cannabis types were profiled and examined for possible associations between frequency of use and (i) cannabis dependence, (ii) cannabis-related concerns. Frequent use of high-potency cannabis predicted a greater severity of dependence [days of skunk use per month: b = 0.254, 95% confidence interval (CI) 0.161-0.357, p cannabis was not associated with dependence (days of other grass use per month: b = 0.020, 95% CI -0.029 to 0.070, p = 0.436; days of resin use per month: b = 0.025, 95% CI -0.019 to 0.067, p = 0.245). Frequency of cannabis use (all types) did not predict severity of cannabis-related concerns. High-potency cannabis was clearly distinct from low-potency varieties by its marked effects on memory and paranoia. It also produced the best high, was preferred, and most available. High-potency cannabis use is associated with an increased severity of dependence, especially in young people. Its profile is strongly defined by negative effects (memory, paranoia), but also positive characteristics (best high, preferred type), which may be important when considering clinical or public health interventions focusing on cannabis potency.

  18. High prevalence of seasonal affective disorder among persons with severe visual impairment.

    Science.gov (United States)

    Madsen, Helle Østergaard; Dam, Henrik; Hageman, Ida

    2016-01-01

    Light severely affects the occurrence of seasonal affective disorder (SAD). To compare the prevalence of SAD in persons with severe visual impairment and persons with full sight, and in persons with severe visual impairment with or without light perception. This cross-sectional study assessed the Global Seasonality Score (GSS) and the prevalence of SAD among 2781 persons with visual impairment and 4099 persons with full sight using the Seasonal Pattern Assessment Questionnaire (SPAQ). Respondents with visual impairment had significantly higher GSS and prevalence of SAD compared with full sight controls, Pseasonal change than both full sight and no light perception respondents. The study showed a highly significant association between visual impairment and SPAQ-defined SAD parameters, supporting the hypothesis that decreased retinal light input plays a role in the pathogenesis of SAD. © The Royal College of Psychiatrists 2016.

  19. Full-length high-temperature severe fuel damage test No. 1

    Energy Technology Data Exchange (ETDEWEB)

    Rausch, W.N.; Hesson, G.M.; Pilger, J.P.; King, L.L.; Goodman, R.L.; Panisko, F.E.

    1993-08-01

    This report describes the first full-length high-temperature test (FLHT-1) performed by Pacific Northwest Laboratory (PNL) in the National Research Universal (NRU) reactor at Chalk River, Ontario, Canada. The test is part of a series of experiments being performed for the NRC as a part of their Severe Fuel Damage Program and is one of several planned for PNL`s Coolant Boilaway and Damage Progression Program. The report summarizes the test design and test plan. it also provides a summary and discussion of the data collected during the test and of the photos taken during the post-test examination. All objectives for the test were met. The key objective was to demonstrate that severe fuel damage tests on full-length fuel bundles can be safely conducted in the NRU reactor.

  20. Cost studies for commercial fuselage crown designs

    Science.gov (United States)

    Walker, T. H.; Smith, P. J.; Truslove, G.; Willden, K. S.; Metschan, S. L.; Pfahl, C. L.

    1991-01-01

    Studies were conducted to evaluate the cost and weight potential of advanced composite design concepts in the crown region of a commercial transport. Two designs from each of three design families were developed using an integrated design-build team. A range of design concepts and manufacturing processes were included to allow isolation and comparison of cost centers. Detailed manufacturing/assembly plans were developed as the basis for cost estimates. Each of the six designs was found to have advantages over the 1995 aluminum benchmark in cost and weight trade studies. Large quadrant panels and cobonded frames were found to save significant assembly labor costs. Comparisons of high- and intermediate-performance fiber systems were made for skin and stringer applications. Advanced tow placement was found to be an efficient process for skin lay up. Further analysis revealed attractive processes for stringers and frames. Optimized designs were informally developed for each design family, combining the most attractive concepts and processes within that family. A single optimized design was selected as the most promising, and the potential for further optimization was estimated. Technical issues and barriers were identified.

  1. Restoring crown fractures by direct composite layering using transparent strip crowns.

    Science.gov (United States)

    Eden, Ece; Taviloğlu, Engin

    2016-04-01

    Traumatic dental injuries are mostly seen at childhood and adolescence. The most common fracture in permanent anterior teeth is crown fracture. Esthetic and easy rehabilitation of these anterior teeth is possible using layering techniques and direct composite resin restorations. Shape, color and surface texture are the most important factors in restoring crown fractures esthetically. This article illustrates how to perform an esthetic composite resin restoration of crown fractures using strip crowns. The technique suggests using a strip crown as a mold for direct resin composite restoration. This provides a cost-effective treatment with operator friendly approach where most outstanding advantage is the minimum chair-side time with a single visit that is very important for young trauma patients. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Sleep disordered breathing in a high-risk cohort prevalence and severity across pregnancy.

    Science.gov (United States)

    Facco, Francesca L; Ouyang, David W; Zee, Phyllis C; Grobman, William A

    2014-11-01

    The objective of this study was to determine the prevalence and incidence of sleep disordered breathing (SDB) in pregnancy among high-risk women. This was a prospective, observational study. We recruited women with a body mass index (BMI) ≥ 30 kg/m(2), chronic hypertension, pregestational diabetes, history of preeclampsia, and/or a twin gestation. Objective assessment of SDB was completed between 6 and 20 weeks and again in the third trimester. SDB was defined as an apnea-hypopnea index (AHI) ≥5, and further grouped into severity categories: mild (5-14.9), moderate (15-29.9) and severe (≥30). Subjects who had a normal AHI at the baseline (AHI pregnancy 21, 6 and 3% had mild, moderate, or severe SDB, respectively. These frequencies increased to 35, 7, and 5% in the third trimester (p pregnancy; 26 were cases of new-onset SDB, while the other 8 had SDB in early pregnancy that worsened in severity. The incidence of new-onset SDB was 20%. The majority of these new-onset cases were mild. SDB in early pregnancy is common in high-risk women and new-onset SDB occurs in 20% of these women. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  3. A 2-year Retrospective Clinical study of Enamic Crowns Performed in a Private Practice Setting.

    Science.gov (United States)

    Chirumamilla, Geetika; Goldstein, Cary E; Lawson, Nathaniel C

    2016-07-01

    To evaluate the clinical performance and survival of Enamic crowns placed in a prosthodontic dental practice. Thirty-five patients and 45 crowns were included in the study. At 1-year recall appointments, the restorations were examined for survival. At the 2-year recall appointment, all restorations were clinically evaluated by an independent evaluator for CDA clinical criteria. Kaplan-Meier method and a log-rank test were used to compare the survival of the restorations placed with resin and resin-modified glass ionomer (RMGI) cements. Out of the 45 crowns that were followed, 2 were lost to follow-up by 1 year and 7 were lost to follow-up by 2 years. Severe complications were observed in 2 teeth by the 2-year follow-up and were recorded as failures due to recurrent decay, and an internal crack in the abutment tooth. There was no difference between the survival probability for crowns cemented with resin cement (96.8%) and with RMGI cements (92.9%) (p = 0.42), however, 1 out of the 14 crowns cemented with RMGI cement debonded. The crowns were evaluated according the CDA criteria with over 90% alfa scores for all categories aside from surface texture (86% alfa). The estimated 2-year survival of Enamic crowns is >90%. Based on the preliminary 2-year results achieved in a clinical practice, Enamic is a suitable material for full-coverage single-unit crowns. Further studies are necessary to evaluate the long term success. (J Esthet Restor Dent 28:231-237, 2016). © 2016 Wiley Periodicals, Inc.

  4. Resistance of full veneer metal crowns with different forms of axial grooves

    Science.gov (United States)

    Hidayat, A. S.; Masulili, C.; Indrasari, M.

    2017-08-01

    Dental crowns or bridges can occasionally come loose or separate from the tooth during chewing, particularly when they are situated on small, short, and conical teeth. The main cause of this separation is a lack of retention and resistance to the tooth. There are several methods available to increase the retention and resistance of the crown during both inlay and onlay preparation, including parallelism, groove preparation, crown build-up, and surface roughness. The aim of this study was to determine the differences in resistance of full veneer metal crowns with various forms of groove preparation. The study involved the compressive strength testing of a total of 24 specimens, namely six specimens without groove preparation, six specimens with box-shaped grooves, six specimens with V-shaped grooves, and six specimens with half round grooves. The mean values of the metal crowns that separated from the teeth during testing were 27.97 ± 1.08 kgF for the crowns with box-shaped grooves, 6.15 ± 0.22 kgF for those with V-shaped grooves, 1.77 ± 0.12 kgF for those with half round grooves, and 0.95 ± 0.13 kgF for those without grooves. This study found that the resistance is best in crowns with box-shaped grooves, followed by those with V-shaped grooves, half round grooves, and those without groove. When clinicians are working on short and conical molar teeth, it is therefore recommended that box-shaped grooves are used to increase the resistance of the crown.

  5. Dynamics of indole-3-acetic acid oxidase activity in suspension culture of sunflower crown-gall

    Directory of Open Access Journals (Sweden)

    Zofia Chirek

    2014-01-01

    Full Text Available IAA oxidase activity was determined in several growth phases of a suspension culture of sunflower crown-gall. During the short phase of intensive growth (zero passage - PO a negative correlation was noted between enzymatic activity and the rate of growth. IAA oxidase activity increased to a certain level is not a factor limiting cell division. For protraction of the phase of intensive growth (first passage - P1, however, a decrease in the activity of this enzyme seems indispensable. IAA oxidase activity in the tested culture is under the control of inhibitors present in the cells and medium. High enzyme inhibition was observed in PO cells during the phase, of intensive growth and in P1 at the beginning and in the middle part of this phase. These results suggest' that the -auxin level determined in earlier studies in sunflower crown-gall culture is controlled by the IAA oxidase set. During the long phase of intensive growth (P1 this control is of negative feedback type.

  6. Severe Refractory Immune Thrombocytopenia Successfully Treated with High-Dose Pulse Cyclophosphamide and Eltrombopag

    Directory of Open Access Journals (Sweden)

    Faiz Anwer

    2015-01-01

    Full Text Available Severe refractory ITP is clinically challenging and a variety of single or combination chemotherapies have been tried with limited outcome. We report a case of ITP that was unresponsive to multiple agents including high-dose steroid, IVIG, Rho(D immune globulin, rituximab, cyclosporine, azathioprine, vincristine, mycophenolate mofetil, romiplostim, and eltrombopag; however, it achieved complete remission with combination treatment of cyclophosphamide and eltrombopag.

  7. A new forest fire paradigm: The need for high-severity fires

    Science.gov (United States)

    Monica L. Bond; Rodney B. Siegel; Richard L. Hutto; Victoria A. Saab; Stephen A. Shunk

    2012-01-01

    Bond, Monica L.; Siegel, Rodney B.; Hutto, Richard L.; Saab, Victoria A.; Shunk, Stephen A. 2012. A new forest fire paradigm: The need for high-severity fires. The Wildlife Professional. Winter 2012: 46-49. During the 2012 fire season from June through August, wildfires in the drought-stricken western and central United States burned more than 3.6 million acres of...

  8. Accuracy of the field triage protocol in selecting severely injured patients after high energy trauma.

    Science.gov (United States)

    van Laarhoven, J J E M; Lansink, K W W; van Heijl, M; Lichtveld, R A; Leenen, L P H

    2014-05-01

    For optimal treatment of trauma patients it is of great importance to identify patients who are at risk for severe injuries. The Dutch field triage protocol for trauma patients, the LPA (National Protocol of Ambulance Services), is designed to get the right patient, in the right time, to the right hospital. Purpose of this study was to determine diagnostic accuracy and compliance of this triage protocol. Triage criteria were categorised into physiological condition (P), mechanism of trauma (M) and injury type (I). A retrospective analysis of prospectively collected data of all high-energy trauma patients from 2008 to 2011 in the region Central Netherlands is performed. Diagnostic parameters (sensitivity, specificity, negative predictive value, positive predictive value) of the field triage protocol for selecting severely injured patients were calculated including rates of under- and overtriage. Undertriage was defined as the proportion of severely injured patients (Injury Severity Score (ISS)≥16) who were transported to a level two or three trauma care centre. Overtriage was defined as the proportion of non-severely injured patients (ISS<16) who were transported to a level one trauma care centre. Overall sensitivity and specificity of the field triage protocol was 89.1% (95% confidence interval (CI) 84.4-92.6) and 60.5% (95% CI 57.9-63.1), respectively. The overall rate of undertriage was 10.9% (95%CI 7.4-15.7) and the overall rate of overtriage was 39.5% (95%CI 36.9-42.1). These rates were 16.5% and 37.7%, respectively for patients with M+I-P-. Compliance to the triage protocol for patients with M+I-P- was 78.7%. Furthermore, compliance in patients with either a positive I+ or positive P+ was 91.2%. The overall rate of undertriage (10.8%) was mainly influenced by a high rate of undertriage in the group of patients with only a positive mechanism criterion, therefore showing low diagnostic accuracy in selecting severely injured patients. As a consequence these

  9. [Photoelastic stress analysis of root dentin with different composite resin post and core systems and crowns].

    Science.gov (United States)

    Takei, Hidenori

    2010-03-01

    Much research has been reported about post and core systems with composite resin, but the influence of the different types of prefabricated posts on the distribution of stress in the root has not yet been elucidated. It is necessary to clarify the influence of the relationship between core and crown materials to obtain combined restorations. The aim of this study is to analyze the influence of the combination of various post and core systems and different kinds of crown material on the stress distribution in the root. Six 2-dimensional photoelastic premolar models were designed. Three types of post and core systems (composite resin post and core, composite resin core with the fiber post, and composite resin core with a prefabricated stainless steel post) and two kinds of crown materials (metal and hybrid-type hard composite resin) were fabricated and cemented to each model. In these models, we applied a load of 200 N at an angle of 45 degrees to the tooth axis and analyzed the fringe order using a transmission polariscope. As a result, it has been clarified that the combination of the post and core and the crown plays an important role in preventing stress concentration within root Stress concentration can be prevented using a crown fabricated with a high-elastic modulus for the post and core with a high-elastic modulus, and a crown fabricated with a low-elastic modulus for the post and core with a low-elastic modulus.

  10. Rock mechanics of crown pillars between cut-and-fill stopes at the Mount Isa mine

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.F.; Bridges, M.C.

    1980-05-15

    At both levels, the leading stopes experienced bad ground conditions due to high stresses in the stope's backs when the crown pillars were about 35 m high. At 9 level, cut-and-fill mining stopped and most of the crown pillars were extracted by a slot-and-massfire method. At 11 level, cut-and-fill mining continued. Shear displacement along bedding planes began within and around the crown pillars of the leading stopes at 11 level, and spread through other crown pillars and to the hangingwall of the stoping system. Destressing and good ground conditions occurred where shear occurred, with further concentrations of stress in other areas. Crown pillars are being extracted to leave minimal 1:2 height to width diaphragms under the stopes above. Ground behavior of the 11 level crown pillars was investigated by observation, stress measurement, regional surveying of displacement and finite element models. An explanation of the ground behavior has evolved from this work. Bedding planes with an estimated angle of sliding friction of 10/sup 0/ were the main factor determining the behavior of this area.

  11. All-ceramic crown preparations: An alternative technique.

    Science.gov (United States)

    Tran, J; Dudley, J; Richards, L

    2017-03-01

    The aim of this study was to compare the crown preparation dimensions produced from two different techniques of preparation for posterior all-ceramic crowns. Twenty-four fourth year dental students undertook a course of advanced simulation training involving education in an alternative technique of preparation for a 36 all-ceramic crown. Crown preparations performed using the traditional technique were compared with an alternative technique for total occlusal convergence (TOC) and reduction difference (RD) using digital scanning and comparative software. Groups that spent the most time performing the alternative technique produced crown preparations with significantly lower buccolingual (BL) TOC. The training resulted in crown preparations that were closer to ideal TOC and RD measurements. The alternative technique of crown preparation for a posterior all-ceramic crown showed initial promise in creating a less buccolingually tapered and more ideally occlusally reduced crown preparation. © 2016 Australian Dental Association.

  12. High fat, high fructose, high cholesterol feeding causes severe NASH and cecal microbiota dysbiosis in juvenile Ossabaw swine

    Science.gov (United States)

    Female Ossabaw swine (5 weeks old) were fed WD (43.0% fat; 17.8% high fructose corn syrup; 2% cholesterol) or low-fat diet (CON/lean; 10.5% fat) for 16 wks (n=6 each) or 36 wks (n=4 each). WD-fed pigs developed obesity, dyslipidemia, and systemic insulin resistance compared with CON pigs. In additio...

  13. Clinical study on high concentrations of sodium hyaluronate eye drops for moderate to severe dry eye

    Directory of Open Access Journals (Sweden)

    Yu-Jing Tian

    2014-06-01

    Full Text Available AIM: To observe the efficacy of high concentrations of sodium hyaluronate(3g/L SHfor moderate to severe dry eye. METHODS: Forty moderate to severe dry eye patients were included in the study according to the diagnosis criteria and randomized into two groups. The patients of the trial group received topical administration of high concentration sodium hyaluronate(3g/L, and those of the control group received sodium hyaluronate(1g/Lplus recombinant human epidermal growth factor. The dry eye symptom scores, ocular surface disease index(OSDIscores, tear film break-up time(BUT, Schirmer Ⅰ test and corneal fluorescein staining score were evaluated.All the indexes were compared between the two groups 2wk before and after treatment. RESULTS: There were no significant differences of the indicators between the two groups before treatment. After 2wk treatment, the differences were statistically significant compared to former except for the Schirmer Ⅰ test. Compared with the control group, the symptom scores and the OSDI scores were lowered. No significant differences were found in the other indicators between these two groups. CONCLUSION: Topical usage of highconcentrations of sodium hyaluronate(3g/Lis beneficial for remitting the ocular symptoms in moderate to severe dry eyes, and also improve the quality of life of patients.

  14. Retrospective Study of Retention of Stainless Steel Crowns and Pre-veneered Crowns on Primary Anterior Teeth.

    Science.gov (United States)

    Lopez-Loverich, Angela M; Garcia, Maria Minerva; Donly, Kevin J

    2015-01-01

    The purpose of this retrospective chart review was to explore the retention of anterior pre-veneered stainless steel crowns (NuSmile) and conventional stainless steel crowns (3M ESPE) placed on primary anterior teeth. Records for children were reviewed over four years using the electronic record system axiUm. Data collected included child's age at time of crown placement, date of placement, tooth number, type of crown, patient behavior, treatment environment, provider type, crown presence, absence, and cementation success or failure at subsequent recall visits. A total of 637 anterior crowns in children treated with either or both crown types met this study's inclusion criteria. Of these crowns, 483 were NuSmile Signature crowns and 154 were stainless steel crowns. There was a nine percent failure rate for the NuSmile Signature crowns and a seven percent failure rate for the stainless steel crowns. There was no statistically significant difference in crown retention rates between the two groups (Pcrown retention rates for both crown types with no statistically significant difference between them (P<0.05).

  15. EL CROWN HALL. CONTEXTO Y PROYECTO

    Directory of Open Access Journals (Sweden)

    Laura Lizondo Sevilla

    2010-05-01

    Full Text Available RESUMEN El artículo enmarca el edificio del Crown Hall en el contexto docente y arquitectónico de Mies van der Rohe. Revisa sus inicios en la Bauhaus con su primera intervención en un espacio docente para la Bauhaus de Berlín en 1932, así como su marcha a Estados Unidos, los planteamientos arquitectónicos del campus del IIT y el proyecto del Crown Hall. El texto incide en el estudio del proceso proyectual del Crown Hall analizando la evolución de su concepción arquitectónica a través de las diferentes versiones del proyecto. Se constata la transición desde los primeros planteamientos arquitectónicos de los edificios del campus del IIT proyectados por Mies hacia el planteamiento del gran espacio unitario del Crown Hall. Este proyecto se puede entender desde la creciente importancia de la estructura, la claridad constructiva y el manejo del acero y vidrio como únicos materiales de la imagen del edificio y el carácter flexible y unitario del espacio. Finalmente se hace referencia al concepto del "espacio universal" en la arquitectura de Mies, como un concepto abstracto que supera los de flexibilidad de uso o unidad espacial, insinuando, a modo de reflexión, las principales variables que definirían el espacio universal miesiano.SUMMARY The article showcases the Crown Hall building in the educational and architectural context of Mies van der Rohe. It reviews his beginnings in the Bauhaus with his first intervention in an educational space for the Bauhaus of Berlin in 1932, as well as his sojourn to the United States, and the architectural approaches to the IIT campus and the Crown Hall project. The text touches on the study of the planning process for the Crown Hall, analysing the evolution of its architectural conception, through the different versions of the project. The article covers the transition from the first architectural approaches for the IIT campus buildings, planned by Mies, to the approach of the large unitary space of

  16. High Strength of Mg-9%Al-1%Zn Alloys Achieved by Severe Working

    Science.gov (United States)

    Okayasu, Mitsuhiro; Muranaga, Takuya

    2017-10-01

    To obtain the excellent mechanical properties of AZ91 magnesium alloy (Mg-8.9%Al-0.6%Zn-0.2%Mn), the microstructural characteristics of AZ91 alloys are modified by various forging and heating processes. High tensile properties (ultimate tensile strength σ UTS = 420 MPa and fracture strain ɛ f = 3%) are obtained for the alloy made by the following process: solution treatment (ST) at 410 °C for 24 h plus water quenching, multidirectional forging (MDF) with 5% strain applied in 15 forgings at room temperature, and warm unidirectional forging (WUF) at a forging rate of 75% at 225 °C. The high tensile strength is a reflection of improved microstructural characteristics, namely a fine α-Mg phase and a high dislocation density. Moreover, brittle β-phase is significantly attributed to the mechanical properties of AZ91 alloy. Because of the severe deformation undergone by the alloy during the MDF process, the solution treatment is important to achieve high ductility with low internal strain, i.e., normalization. In fact, the ɛ f value for the ST sample is as high as 10%, leading to severe work hardening during the tensile test, with deformation twins and slips. The WUF process is conducted immediately after the sample has been heated to 225 °C, for less than 5 min, to avoid material softening. A relatively high tensile strength ( σ UTS = 305 MPa) is also achieved using the WUF process (with a forging rate of 75% at 200 °C) after the ST and aging process (200 °C for 12 h) although low ductility is found ( ɛ f = 0.7%), with hard and brittle β-phases being precipitated around the grain boundaries.

  17. Cumulative effects of successive restorative procedures on anterior crown flexure: intact versus veneered incisors.

    Science.gov (United States)

    Magne, P; Douglas, W H

    2000-01-01

    When successive restorative procedures (e.g., porcelain veneers, interdental resin composite restorations, and endodontic treatment) are carried out on the same tooth, significant effects on crown flexure can be expected. Dentin-bonded porcelain veneers (experimental group) were assessed in vitro using functional and cyclic thermal loads. They were compared to natural teeth (control group) with respect to 2 parameters: coronal flexure (investigated using experimental strain gauges) and morphology of the tooth-restoration interface (scanning electron microscopic evaluation). For both veneered and natural teeth, crown deformation was recorded at 5 sequential experimental steps: intact tooth (baseline), Class III cavities, Class III resin composite restorations, endodontic treatment, and endodontic restoration (without posts). No significant differences in crown flexure were found between natural and veneered incisors when compared across experimental steps. The main effect for experimental steps was highly significant. When averaged across all specimens (natural and veneered teeth), the endodontic treatment step resulted in the highest crown flexure (1.55x the baseline value). The unrestored Class III cavities and the endodontic restoration were next highest (1.30x and 1.28x the baseline value, respectively). The lowest crown flexures were found after restoration of the Class III cavities (1.13x the baseline value). No measurable microleakage or gaps were detected at the ceramic-resin, resin-enamel, or resin-dentin interfaces (Optibond FL, Kerr). Each subsequent reduction in tooth structure resulted in a substantial increase in crown flexibility, even after restoration. Endodontic procedures were responsible for most of the loss in crown stiffness. Extensive proximal cutting and restorations seemed to minimally affect crown flexure. Porcelain veneers showed perfect biomimetic behavior, because cumulated restoration procedures had the same effect on natural and

  18. High Prevalence of Obstructive Sleep Apnea in Patients with Moderate to Severe Chronic Obstructive Pulmonary Disease.

    Science.gov (United States)

    Soler, Xavier; Gaio, Eduardo; Powell, Frank L; Ramsdell, Joe W; Loredo, Jose S; Malhotra, Atul; Ries, Andrew L

    2015-08-01

    When obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) coexist in the so-called "overlap" syndrome, a high risk for mortality and morbidity has been reported. There is controversy about the prevalence of OSA in people affected by COPD. The purpose of this study was to investigate objective meaures of sleep-disordered breathing in patients with moderate to severe COPD to test the hypothesis that COPD is associated with an increased prevalence of OSA. Fifty-four patients (54% men) with moderate to severe COPD were enrolled prospectively (mean ± SD, FEV1 = 42.8 ± 19.8% predicted, and FEV1/FVC = 42.3 ± 13.1). Twenty patients (37%) were on supplemental oxygen at baseline. Exercise tolerance; questionnaires related to symptoms, sleep, and quality of life; and home polysomnography were obtained. Forty-four patients had full polysomnography suitable for analysis. OSA (apnea-hypopnea index > 5/h) was present in 29 subjects (65.9%). Sleep efficiency was poor in 45% of subjects. OSA is highly prevalent in patients with moderate to severe COPD referred to pulmonary rehabilitation. Sleep quality is also poor among this selected group. These patients have greater-than-expected sleep-disordered breathing, which could be an important contributory factor to morbidity and mortality. Pulmonary rehabilitation programs should consider including a sleep assessment in patients with moderate to severe COPD and interventions when indicated to help reduce the impact of OSA in COPD.

  19. Forecasting of Severe Weather in Austria and Hungary Using High-Resolution Ensemble Prediction System

    Science.gov (United States)

    Szucs, Mihaly; Simon, Andre; Szintai, Balazs; Suklitsch, Martin; Wang, Yong; Wastl, Clemens; Boloni, Gergely

    2015-04-01

    The study presents and compares several approaches in EPS (ensemble prediction system) forecasting based on the non-hydrostatic, high resolution AROME model. The PEARP (global ARPEGE model EPS) was used for coupling. Besides, AROME-EPS was also generated upon hydrostatic ALADIN-EPS forecasts (LAEF), which were used as initial and lateral boundary conditions for each AROME-EPS run. The horizontal resolution of the AROME model is 2.5km and it uses 60 vertical levels for the vertical discretization. In most of the tests, the AROME-EPS run with 10+1 members in Hungarian and 16 members in Austrian implementation. The forecast length was usually set to 30-36 hours. The use of high-resolution EPS has advantages in almost all situations with severe convection (mostly in forecasting intense multicell thunderstorms or mesoscale convective systems of non-frontal origin). The possibility of severe thunderstorm was indicated by several EPS runs even if the deterministic (reference) AROME model failed to forecast the event. Similarly, it could be shown that the AROME-EPS can perform better than hydrostatic global or ALADIN-EPS models in situations with strong wind or heavy precipitation induced by large-scale circulation (mainly in mountain regions). Both EDA (Ensemble of Data Assimilation) and SPPT (Stochastically Perturbed Parameterized Tendencies) methods were tested as a potential perturbation generation method on limited area. The EDA method was able to improve the accuracy of single members through the reduction of the analysis error by applying local data assimilation. It was also able to increase the spread of the system in the early hours due to the additional analysis perturbations. The impact of the SPPT scheme was proven to be smaller in comparison to the impact of this method in global ensemble systems. Further possibilities of improving the assimilation methods and the setup of the AROME-EPS are also discussed.

  20. [The method of esthetic crown restoration with composite resin jacket crown in primary molars].

    Science.gov (United States)

    Doi, K; Shibui, N; Suda, M; Uehara, M; Karibe, H; Kondou, K

    1990-10-01

    The term "esthetics" has recently been also used in the dental field, and a field called esthetic dentistry is increasingly being noted. The number of not only adult but also pediatric patients who visit for treatment aiming at esthetic recovery is being increased. Inpedodontics, composite resin of the coronal color is generally used in the restoration of deciduous incisors. However, the method using metal crowns for the deciduous teeth is used for the deciduous molars at present. We applied a composite resin jacket crown to the deciduous molar in a way similar to that of esthetic crown restoration for the anterior teeth. The surgical procedure before crown preparation varied slightly according to the presence or absence of pulpal treatment of vital teeth and with non-vital teeth, but the application was performed as follows: 1) Desensitization of pulp, pulpal treatment and core construction. 2) Preparation of crown. 3) Selection, trial set and occlusal equilibration of a metal crown for the deciduous tooth. 4) Precision impression with a silicone impression material. 5) Removal of the metal crown for the deciduous tooth from the impression material. 6) Making of an under-cut to the abutment tooth on the buccal lingual side. 7) Filling of the impression with chemical polymerization resin. 8) Application of pressure in the oral cavity. 9) Adjustment of edge and crown forms. Thus, the preparation method for the composite resin jacket crown was relatively simple. Since this surgery, the patient has been followed up for 1 year and 6 months, and no specifically troublesome points have been observed clinically. The patient and her parents are satisfied with the results.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Utilization of stainless steel crowns by general dentists and pediatric dental specialists in Indiana.

    Science.gov (United States)

    Kowolik, Joan; Kozlowski, Diana; Jones, James E

    2007-01-01

    The purpose of this study was to evaluate utilization of the stainless steel crown by both the general and pediatric dentists in Indiana. Although reports indicate that there has been a dramatic reduction in dental caries in the US, almost 20 percent of children have dental decay by age four, with almost 80 percent having a cavity by 17 years of age. After reviewing the literature, Seale has recommended that the stainless steel crown is the most successful restoration for children with a rate of high caries. All dental schools in North America teach the value of using stainless steel crowns and the method of tooth preparation. We hypothesized that greater use of the stainless steel crowns would be made by specialists than by general dentists. In this study, of the 200 questionnaires distributed, 62.5 percent were returned and analyzed. The results imply that stainless steel crowns are being significantly underutilized in general dental practice. It is interesting, and perhaps of concern, that the general dentists are not interested in continuing education courses about this subject. Over the next few years, with the aging of the pediatric dental community in Indiana, general (not specialty) dentists will treat most of the children. Because of this, pre-doctoral education needs to place more emphasis on preparation and utilization of the stainless steel crown.

  2. Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns.

    Science.gov (United States)

    Mitov, Gergo; Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter

    2016-02-01

    The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling 5℃-55℃ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at 137℃, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns.

  3. Effect of crown to implant ratio and implant dimensions on periimplant stress of splinted implant-supported crowns: a finite element analysis.

    Science.gov (United States)

    Bayraktar, Mehmet; Gultekin, B Alper; Yalcin, Serdar; Mijiritsky, Eitan

    2013-08-01

    To assess the influence of different crown-implant (C/I) ratios and implant dimensions on periimplant stress in the partially edentulous posterior mandible by 3-dimensional finite element analysis (FEA). Two implants were placed in the second premolar and first molar regions of the mandibular model. The implants were then splinted with a 2-unit fixed bridge. The influence of 3 parameters (C/I ratio, implant length, and implant diameter) on periimplant bone stress was then analyzed by using FEA. C/I ratios showed a direct relationship with periimplant bone stress, but the absolute height of the clinical crown had a much more significant influence. The implant length had less influence on the periimplant bone stress than the implant diameter. Lower stress values were detected in wide-diameter implants, even in scenarios involving long crowns. Crown height is a more important factor affecting the periimplant bone stress than the C/I ratio for splinted implant-supported crowns. Two-unit fixed restorations with high C/I ratios may be successfully used with wide-diameter implants in the posterior mandible.

  4. High-frequency percussive ventilation in severe acute respiratory distress syndrome: A single center experience

    Directory of Open Access Journals (Sweden)

    Herbert Spapen

    2014-01-01

    Full Text Available Background: Few studies have investigated high-frequency percussive ventilation (HFPV in adult patients with acute respiratory distress syndrome (ARDS. Materials and Methods: We retrospectively analyzed data from critically ill-patients with moderate and severe ARDS who received HFPV. Ventilation and oxygenation were governed according to a predefined protocol. HFPV was continued until patients could be switched to conventional ventilation. Results: A total of 42 patients (20 with pneumonia-related ARDS and 22 non-septic ARDS cases were evaluable. Baseline demographic characteristics, severity of illness, lung injury score; pH and respiratory variables were comparable between pneumonia and non-sepsis-related ARDS. Within 24 h, HFPV restored normal pH and PaCO 2 and considerably improved oxygenation. Oxygenation improved more in non-septic than in pneumonia-related ARDS. Patients with pneumonia-induced ARDS also remained longer HFPV-dependent (7.0 vs. 4.9 days; P < 0.05. Mortality at 30 days was significantly higher in pneumonia-related than in non-sepsis-related ARDS (50% vs. 18%; P = 0.01. Conclusions: HFPV caused rapid and sustained improvement of oxygenation and ventilation in patients with moderate to severe ARDS. Less improved oxygenation, longer ventilator dependency and worse survival were observed in pneumonia-related ARDS.

  5. Randomized controlled trial of levamisole hydrochloride as adjunctive therapy in severe falciparum malaria with high parasitemia.

    Science.gov (United States)

    Maude, Richard J; Silamut, Kamolrat; Plewes, Katherine; Charunwatthana, Prakaykaew; Ho, May; Abul Faiz, M; Rahman, Ridwanur; Hossain, Md Amir; Hassan, Mahtab U; Bin Yunus, Emran; Hoque, Gofranul; Islam, Faridul; Ghose, Aniruddha; Hanson, Josh; Schlatter, Joel; Lacey, Rachel; Eastaugh, Alison; Tarning, Joel; Lee, Sue J; White, Nicholas J; Chotivanich, Kesinee; Day, Nicholas P J; Dondorp, Arjen M

    2014-01-01

    Cytoadherence and sequestration of erythrocytes containing mature stages of Plasmodium falciparum are central to the pathogenesis of severe malaria. The oral anthelminthic drug levamisole inhibits cytoadherence in vitro and reduces sequestration of late-stage parasites in uncomplicated falciparum malaria treated with quinine. Fifty-six adult patients with severe malaria and high parasitemia admitted to a referral hospital in Bangladesh were randomized to receive a single dose of levamisole hydrochloride (150 mg) or no adjuvant to antimalarial treatment with intravenous artesunate. Circulating late-stage parasites measured as the median area under the parasite clearance curves were 2150 (interquartile range [IQR], 0-28 025) parasites/µL × hour in patients treated with levamisole and 5489 (IQR, 192-25 848) parasites/µL × hour in controls (P = .25). The "sequestration ratios" at 6 and 12 hours for all parasite stages and changes in microvascular blood flow did not differ between treatment groups (all P > .40). The median time to normalization of plasma lactate (levamisole vs 28 (IQR, 12-36) hours without levamisole (P = .15). There was no benefit of a single-dose of levamisole hydrochloride as adjuvant to intravenous artesunate in the treatment of adults with severe falciparum malaria. Rapid parasite killing by intravenous artesunate might obscure the effects of levamisole.

  6. Clinical heterogeneity among people with high functioning autism spectrum conditions: evidence favouring a continuous severity gradient

    Directory of Open Access Journals (Sweden)

    Woodbury-Smith Marc

    2008-02-01

    Full Text Available Abstract Background Autism Spectrum Conditions (ASCs are characterized by a high degree of clinical heterogeneity, but the extent to which this variation represents a severity gradient versus discrete phenotypes is unclear. This issue has complicated genetic studies seeking to investigate the genetic basis of the high hereditability observed clinically in those with an ASC. The aim of this study was to examine the possible clustering of symptoms associated with ASCs to determine whether the observed distribution of symptom type and severity supported either a severity or a symptom subgroup model to account for the phenotypic variation observed within the ASCs. Methods We investigated the responses of a group of adults with higher functioning ASCs on the fifty clinical features examined in the Autism Spectrum Quotient, a screening questionnaire used in the diagnosis of higher functioning ASCs. In contrast to previous studies we have used this instrument with no a priori assumptions about any underlying factor structure of constituent items. The responses obtained were analyzed using complete linkage hierarchical cluster analysis. For the members of each cluster identified the mean score on each Autism Spectrum Quotient question was calculated. Results Autism Spectrum Quotient responses from a total of 333 individuals between the ages of 16.6 and 78.0 years were entered into the hierarchical cluster analysis. The four cluster solution was the one that generated the largest number of clusters that did not also include very small cluster sizes, defined as a membership comprising 10 individuals or fewer. Examination of these clusters demonstrated that they varied in total Autism Spectrum Quotient but that the profiles across the symptoms comprising the Autism Spectrum Quotient did not differ independently of this severity factor. Conclusion These results are consistent with a unitary spectrum model, suggesting that the clinical heterogeneity observed

  7. Clinical heterogeneity among people with high functioning autism spectrum conditions: evidence favouring a continuous severity gradient

    Science.gov (United States)

    Ring, Howard; Woodbury-Smith, Marc; Watson, Peter; Wheelwright, Sally; Baron-Cohen, Simon

    2008-01-01

    Background Autism Spectrum Conditions (ASCs) are characterized by a high degree of clinical heterogeneity, but the extent to which this variation represents a severity gradient versus discrete phenotypes is unclear. This issue has complicated genetic studies seeking to investigate the genetic basis of the high hereditability observed clinically in those with an ASC. The aim of this study was to examine the possible clustering of symptoms associated with ASCs to determine whether the observed distribution of symptom type and severity supported either a severity or a symptom subgroup model to account for the phenotypic variation observed within the ASCs. Methods We investigated the responses of a group of adults with higher functioning ASCs on the fifty clinical features examined in the Autism Spectrum Quotient, a screening questionnaire used in the diagnosis of higher functioning ASCs. In contrast to previous studies we have used this instrument with no a priori assumptions about any underlying factor structure of constituent items. The responses obtained were analyzed using complete linkage hierarchical cluster analysis. For the members of each cluster identified the mean score on each Autism Spectrum Quotient question was calculated. Results Autism Spectrum Quotient responses from a total of 333 individuals between the ages of 16.6 and 78.0 years were entered into the hierarchical cluster analysis. The four cluster solution was the one that generated the largest number of clusters that did not also include very small cluster sizes, defined as a membership comprising 10 individuals or fewer. Examination of these clusters demonstrated that they varied in total Autism Spectrum Quotient but that the profiles across the symptoms comprising the Autism Spectrum Quotient did not differ independently of this severity factor. Conclusion These results are consistent with a unitary spectrum model, suggesting that the clinical heterogeneity observed in those with an autistic

  8. Clinical heterogeneity among people with high functioning autism spectrum conditions: evidence favouring a continuous severity gradient.

    Science.gov (United States)

    Ring, Howard; Woodbury-Smith, Marc; Watson, Peter; Wheelwright, Sally; Baron-Cohen, Simon

    2008-02-20

    Autism Spectrum Conditions (ASCs) are characterized by a high degree of clinical heterogeneity, but the extent to which this variation represents a severity gradient versus discrete phenotypes is unclear. This issue has complicated genetic studies seeking to investigate the genetic basis of the high hereditability observed clinically in those with an ASC. The aim of this study was to examine the possible clustering of symptoms associated with ASCs to determine whether the observed distribution of symptom type and severity supported either a severity or a symptom subgroup model to account for the phenotypic variation observed within the ASCs. We investigated the responses of a group of adults with higher functioning ASCs on the fifty clinical features examined in the Autism Spectrum Quotient, a screening questionnaire used in the diagnosis of higher functioning ASCs. In contrast to previous studies we have used this instrument with no a priori assumptions about any underlying factor structure of constituent items. The responses obtained were analyzed using complete linkage hierarchical cluster analysis. For the members of each cluster identified the mean score on each Autism Spectrum Quotient question was calculated. Autism Spectrum Quotient responses from a total of 333 individuals between the ages of 16.6 and 78.0 years were entered into the hierarchical cluster analysis. The four cluster solution was the one that generated the largest number of clusters that did not also include very small cluster sizes, defined as a membership comprising 10 individuals or fewer. Examination of these clusters demonstrated that they varied in total Autism Spectrum Quotient but that the profiles across the symptoms comprising the Autism Spectrum Quotient did not differ independently of this severity factor. These results are consistent with a unitary spectrum model, suggesting that the clinical heterogeneity observed in those with an autistic spectrum condition at the higher-IQ end

  9. PREFORMED METAL CROWNS FOR THE PERMANENT DENTITION.

    Science.gov (United States)

    Millar, Lynsey M; Cairns, Alison M; Fowler, Lauren

    2015-11-01

    Preformed metal crowns have a range of uses in paediatric dentistry in both the primary and permanent dentition. This article provides an overview of their use in permanent teeth, including teeth that have been affected by molar incisor hypomineralisation, caries, developmental defects and tooth surface loss. The indications for use are described, along with the clinical technique for placement

  10. Paraphoma crown rot of pyrethrum (Tanacetum cinerariifolium)

    NARCIS (Netherlands)

    Moslemi, Azin; Ades, Peter Kevin; Groom, Tim; Crous, Pedro; Nicolas, Marc Edward; Taylor, Paul William James

    2016-01-01

    Pyrethrum (Tanacetum cinerariifolium) is commercially cultivated for the extraction of natural pyrethrin insecticides from the oil glands inside seeds. Yield-decline has caused significant yield losses in Tasmania during the last decade. A new pathogen of pyrethrum causing crown rot and reduced

  11. Confronting Stereotypes: "Maus" in Crown Heights.

    Science.gov (United States)

    Loewenstein, Andrea Freud

    1998-01-01

    Concentrates specifically on the experience of using "Maus" (a narrative in comic strip form) with one class which met in spring 1996, after the accidental killing of a Black child by a Hasidic Jew in Crown Heights, New York. Uses the text at Medgar Evers College in a freshman composition course which also functions as an introduction to…

  12. Investigations of several interference effects in high frequency plasmas of analytical importance

    Energy Technology Data Exchange (ETDEWEB)

    Larson, G.F.

    1977-02-01

    Investigations of the extent to which certain inter-element or interference effects occur in a radiofrequency-excited inductively coupled plasma (ICP) are reported. Under conditions normally employed for analytical purposes, it is shown that: (a) two solute vaporization interferences often observed in flames are eliminated or reduced to negligible proportions in the plasma; (b) increasing concentrations of an easily ionizable element (Na) up to concentrations of 6900 ..mu..g/ml exerted an unusually low influence on the observed emission intensities of three selected elements (Ca, Cr, and Cd) of widely differing degrees of ionization. The high degree of freedom from interelement effects of this analytical technique is further documented by the observation that a variety of matrices did not affect the emission intensity of Mo to a significant extent. A comparison of the degree to which several interference effects are observed in a microwave-excited single electrode plasma (SEP) and in an ICP shows that the severe changes observed in the SEP are small or negligible in the ICP. The spectral interferences arising from stray light and from the wings of broadened emission lines in atomic emission spectrometry are discussed. Experimental evidence is presented showing various forms of stray light originating from defects in the optical components, design and engineering of optical spectrometers. Experimental evidence is also presented demonstrating that the wings of certain spectral lines emitted by high temperature sources may contribute a significant continuum at wavelengths as far removed as 10 nm or more from the line center.

  13. High-mobility group box 1 protein and its role in severe acute pancreatitis

    Science.gov (United States)

    Shen, Xiao; Li, Wei-Qin

    2015-01-01

    The high mobility group box 1 (HMGB1), which belongs to the subfamily of HMG-1/-2, is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da. HMGB1 is a ubiquitous nuclear protein in mammals and plays a vital role in inflammatory diseases. Acute pancreatitis is one of the most common causes of acute abdominal pain with a poor prognosis. Acute pancreatitis is an acute inflammatory process of the pancreas (duration of less than six months), for which the severe form is called severe acute pancreatitis (SAP). More and more studies have shown that HMGB1 has a bidirectional effect in the pathogenesis of SAP. Extracellular HMGB1 can aggravate the pancreatic inflammatory process, whereas intracellular HMGB1 has a protective effect against pancreatitis. The mechanism of HMGB1 is multiple, mainly through the nuclear factor-κB pathway. Receptors for advanced glycation end-products and toll-like receptors (TLR), especially TLR-2 and TLR-4, are two major types of receptors mediating the inflammatory process triggered by HMGB1 and may be also the main mediators in the pathogenesis of SAP. HMGB1 inhibitors, such as ethyl pyruvate, pyrrolidine dithiocarbamate and Scolopendra subspinipes mutilans, can decrease the level of extracellular HMGB1 and are the promising targets in the treatment of SAP. PMID:25663762

  14. Internal adaptation of cast titanium crowns

    Directory of Open Access Journals (Sweden)

    Sicknan Soares da Rocha

    2007-08-01

    Full Text Available As the adaptation of titanium crowns obtained by Rematitan Plus investment, specific for titanium, is not recognized to be suitable, this study evaluated the effect of the concentration of the specific liquid and the temperature of the mold of investments on the internal misfit of crowns cast on commercially pure titanium. Individual dies of epoxy resin were obtained, representing teeth prepared for full-crown restoration with a 6-degree axial surface convergence angle and shoulder (1.0 mm. For the waxing of each crown, a ring-shaped stainless steel matrix (8.0mm internal diameter; 7.5 mm height was adapted above the individual dies of epoxy resin. The Rematian Plus investment was mixed according to the manufacturer's instructions using two different concentrations of the specific liquid: 100%, 75%. Casting was performed in a Discovery Plasma Ar-arc vacuum-pressure casting machine with molds at temperatures of 430ºC, 515ºC and 600ºC. The crowns were cleaned individually in a solution (1% HF + 13% HNO3 for 10 min using a ultrasonic cleaner, with no internal adaptations, and luted with zinc phosphate cement under a 5 kg static load. The crown and die assemblies were embedded in resin and sectioned longitudinally. The area occupied by cement was observed using stereoscopic lens (10X and measured by the Leica Qwin image analysis system (mm². The data for each experimental condition (n=8 were analyzed by Kruskal-Wallis non-parametric test (á=0.05. The results showed that liquid dilution and the increase in mold temperature did not significantly influence the levels of internal fit of the cast titanium crowns. The lowest means (±SD of internal misfit were obtained for the 430ºC/100%: (7.25 mm² ±1.59 and 600ºC/100% (8.8 mm² ±2.25 groups, which presented statistically similar levels of internal misfit.

  15. Severe beta blocker and calcium channel blocker overdose: Role of high dose insulin.

    Science.gov (United States)

    Seegobin, Karan; Maharaj, Satish; Deosaran, Ansuya; Reddy, Pramod

    2018-01-10

    A 54-year-old female presented after taking an overdose of an unknown amount of hydrochlorothiazide, doxazocin, atenolol and amlodipine. She was initially refractory to treatment with conventional therapy (intravenous fluids, activated charcoal, glucagon 5 mg followed with glucagon drip, calcium gluconate 10%, and atropine). Furthermore, insulin at 4 U/kg was not effective in improving her hemodynamics. Shortly after high dose insulin was achieved with 10 U/kg, there was dramatic improvement in hemodynamics resulting in three of five vasopressors being weaned off in 8 h. She was subsequently off all vasopressors after six additional hours. The role of high dose insulin has been documented in prior cases, however it is generally recommended after other conventional therapies have failed. However, there are other reports that suggest it as initial therapy. Our patient failed conventional therapies and responded well only with maximum dose of insulin. Physicians should consider high dose insulin early in severe beta blocker or calcium channel blocker overdose for improvement in hemodynamics. This leads to early discontinuation of vasopressors. It is important that emergency physicians be aware of the beneficial effects of high dose insulin when initiated early as opposed to waiting for conventional therapy to fail; as these patients often present first to the emergency department. Early initiation in the emergency department can be beneficial in these patients. Copyright © 2018. Published by Elsevier Inc.

  16. Influence of cement film thickness on the retention of implant-retained crowns.

    Science.gov (United States)

    Mehl, Christian; Harder, Sönke; Steiner, Martin; Vollrath, Oliver; Kern, Matthias

    2013-12-01

    The main goal of this study was to establish a new, high precision procedure to evaluate the influence of cement film thickness on the retention of cemented implant-retained crowns. Ninety-six tapered titanium abutments (6° taper, 4.3 mm diameter, Camlog) were shortened to 4 mm. Computer-aided design was used to design the crowns, and selective laser sintering, using a cobalt-chromium alloy, was used to produce the crowns. This method used a focused high-energy laser beam to fuse a localized region of metal powder to build up the crowns gradually. Before cementing, preset cement film thicknesses of 15, 50, 80, or 110 μm were established. Glass ionomer, polycarboxylate, or resin cements were used for cementation. After 3 days storage in demineralized water, the retention of the crowns was measured in tension using a universal testing machine. The cement film thicknesses could be achieved with a high level of precision. Interactions between the factors cement and cement film thickness could be found (p ≤ 0.001). For all cements, crown retention decreased significantly between a cement film thickness of 15 and 50 μm (p ≤ 0.001). At 15 μm cement film thickness, the resin cement was the most retentive cement, followed by the polycarboxylate and then the glass ionomer cement (p ≤ 0.05). The results suggest that cement film thickness has an influence on the retentive strength of cemented implant-retained crowns. © 2013 by the American College of Prosthodontists.

  17. Climate drives inter-annual variability in probability of high severity fire occurrence in the western United States

    Science.gov (United States)

    Keyser, Alisa; Westerling, Anthony LeRoy

    2017-05-01

    A long history of fire suppression in the western United States has significantly changed forest structure and ecological function, leading to increasingly uncharacteristic fires in terms of size and severity. Prior analyses of fire severity in California forests showed that time since last fire and fire weather conditions predicted fire severity very well, while a larger regional analysis showed that topography and climate were important predictors of high severity fire. There has not yet been a large-scale study that incorporates topography, vegetation and fire-year climate to determine regional scale high severity fire occurrence. We developed models to predict the probability of high severity fire occurrence for the western US. We predict high severity fire occurrence with some accuracy, and identify the relative importance of predictor classes in determining the probability of high severity fire. The inclusion of both vegetation and fire-year climate predictors was critical for model skill in identifying fires with high fractional fire severity. The inclusion of fire-year climate variables allows this model to forecast inter-annual variability in areas at future risk of high severity fire, beyond what slower-changing fuel conditions alone can accomplish. This allows for more targeted land management, including resource allocation for fuels reduction treatments to decrease the risk of high severity fire.

  18. New atraumatic easy removal technique for permanently cemented crown

    Directory of Open Access Journals (Sweden)

    Pravinkumar G Patil

    2012-01-01

    Full Text Available Removal of a permanently cemented crown or fixed partial denture is a cumbersome procedure for a prosthodontist, especially when there is no purchase point available to remove it. The technique described in this article consists of sectioning of a crown on facial surface followed by removal of the crown with orthodontic plier. This technique does not damage the gingival/periodontal tissues or underlying tooth structure as the crown need not to be removed with jerky back-action force.

  19. Two-body wear comparison of zirconia crown, gold crown, and enamel against zirconia.

    Science.gov (United States)

    Kwon, Min-Seok; Oh, Sang-Yeob; Cho, Sung-Am

    2015-07-01

    Full zirconia crowns have recently been used for dental restorations because of their mechanical properties. However, there is little information about their wear characteristics against enamel, gold, and full zirconia crowns. The purpose of this study was to compare the wear rate of enamel, gold crowns, and zirconia crowns against zirconia blocks using an in vitro wear test. Upper specimens were divided into three groups: 10 enamels (group 1), 10 gold crowns (group 2, Type III gold), and 10 zirconia crowns (group 3, Prettau(®)Zirkon 9H, Zirkonzahn, Italy). Each of these specimens was wear tested against a zirconia block (40×30×3mm(3)) as a lower specimen (30 total zirconia blocks). Each specimen of the groups was abraded against the zirconia block for 600 cycles at 1Hz with 15mm front-to-back movement on an abrading machine. Moreover, the load applied during the abrading test was 50N, and the test was performed in a normal saline emulsion for 10min. Three-dimensional images were taken before and after the test, and the statistical analysis was performed using the Krushal-Wallis test and Mann-Whitney test (p=0.05). The mean volume loss of group 1 was 0.47mm(3), while that of group 2 and group 3 was 0.01mm(3). The wear volume loss of enamels against zirconia was higher than that of gold and zirconia crowns. Moreover, according to this result, zirconia crowns are not recommended for heavy bruxers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Cement application techniques in luting implant-supported crowns: a quantitative and qualitative survey.

    Science.gov (United States)

    Wadhwani, Chandur; Hess, Timothy; Piñeyro, Alfonso; Opler, Richard; Chung, Kwok-Hung

    2012-01-01

    To investigate different techniques used by dentists when luting an implant-supported crown and to evaluate the application of cement quantitatively and qualitatively. Participants were given a bag containing cement sachet, mixing pad, spatula, a variety of application instruments, and a polycarbonate crown form. The participants were instructed with a standardized audio-video presentation to proportion the cement, mix it, and apply it to the intaglio of the crown as they would if they were to cement it onto an implant abutment in a clinical situation. The crowns were weighed, first unfilled and then again once the applied cement had set. The mean weights of fully-loaded crowns (n = 10) were used as a control group. The patterns of cement loading were recorded. The weights of collected cement-loaded crowns were compared to those of the control group and analyzed statistically. Four hundred and one dentists in several different geographic locations were surveyed. Three distinct cement loading patterns were observed: gross application (GA), brush-on application (BA), and margin application (MA). The mean weights for each cement loading pattern were 242.2 mg for the GA group, 59.9 mg for the BA group, and 59.0 mg for the MA group. The weight of cement in the GA group was significantly higher than that in the other groups. No statistically significant difference between groups BA and MA was seen. The diversity of the cement loading patterns disclosed in this study indicates that there is a lack of uniformity and precision in methods and a lack of consensus in the dental community regarding the appropriate quantity of cement and placement method for a cement-retained implant crown.

  1. Modeling crown structural responses to competing vegetation control, thinning, fertilization, and Swiss needle cast in coastal Douglas-fir of the Pacific Northwest, USA.

    Science.gov (United States)

    A.R. Weiskittel; D.A. Maguire; R.A. Monserud

    2007-01-01

    Crown structure is a key variable influencing stand productivity, but its reported response to various stand factors has differed. This can be partially attributed to lack of a unified study on crown response to intensive management or stand health. In this analysis of several Douglas-fir (Pseudotsuga menziesii var. menziesii [...

  2. 21 CFR 872.3770 - Temporary crown and bridge resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Temporary crown and bridge resin. 872.3770 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a material, such as...

  3. Parsimonious Crown Diameter Prediction Models for Tectona Grandis

    African Journals Online (AJOL)

    Parsimonious Crown Diameter Prediction Models for Tectona Grandis (Linn f Verbenaceae). FS Popo-ola, BA Oyebade,. Abstract. Tree crown is one complement of net primary production and its dimensions reflect general tree health. Crown diameter is often used as an important predictor variable for tree growth equation.

  4. Crown dilacerations - Two case reports | Rao | Nigerian Dental Journal

    African Journals Online (AJOL)

    Crown dilaceration is a relatively abnormal clinical finding when compared to root dilacerations. The incidence of crown dilacerations is stated to be as low as 3%. This report presents two cases of crown dilacerations in two different locations. A brief review of the literature pertinent to the condition, and the clinical and ...

  5. Fatigue resistance of CAD/CAM resin composite molar crowns.

    NARCIS (Netherlands)

    Shembish, F.A.; Tong, H.; Kaizer, M.; Janal, M.N.; Thompson, V.P.; Opdam, N.J.M.; Zhang, Y.

    2016-01-01

    OBJECTIVE: To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. METHODS: Fully anatomically shaped monolithic resin composite molar crowns (Lava

  6. Distribution And Types Of Artificial Crowns And Bridges Prescribed ...

    African Journals Online (AJOL)

    There were no statically crowned tooth was the maxillary central incisor constituting 59.7 per cent. All – resin crowns were the most prescribed (59.2 per cent) followed was porcelain – fused to – metal crowns (38. 1 per cent). A total of 68 fixed partial dentures, consisting of 178 retainers and 117 poetics made for 68 patients

  7. Evaluation of sampling strategies to estimate crown biomass

    Science.gov (United States)

    Krishna P Poudel; Hailemariam Temesgen; Andrew N Gray

    2015-01-01

    Depending on tree and site characteristics crown biomass accounts for a significant portion of the total aboveground biomass in the tree. Crown biomass estimation is useful for different purposes including evaluating the economic feasibility of crown utilization for energy production or forest products, fuel load assessments and fire management strategies, and wildfire...

  8. Precise Hugoniot data and EOS properties to 2 Mbars for several high-pressure standards

    Science.gov (United States)

    Mashimo, Tsutomu; Liu, Xun; Fukuno, Taisei; Katsuyama, Tatsuhiro; Zaretsky, Eugene; Nagayama, Kunihito

    2017-06-01

    Pressure calibration in static compression experiments is usually undertaken on the basis of the equation of state (EOS) of materials used as a pressure standard, such as Au, Pt, Ag, Cu, MgO, etc. derived from their Hugoniot-compression curves (Au scale, Pt scale, Ruby scale, etc.). To derive true equations of state (EOS) from these standards, precise Hugoniot data are needed, including material strength in order to drive the isothermal hydrostatic compression curve. To accomplish this objective, we have implemented a high-speed streak camera measurement system consisting of a rotating-mirror type streak camera aBnd a pulsed dye laser combined with a one-stage powder gun and a two-stage light gas gun to obtain Hugoniot curves. We achieved measurement errors for shock and particle velocities of 0.3% and 0.1%-0.2%, respectively, for each shot, which enables us to analyze the influence of shear strength and the Grüneisen parameter. We have obtained highly accurate Hugoniot data for W, Cu, Au, Pt, Ag, MgO up to 2.3 Mbars. We also performed the VISAR experiments to access the strength for several materials. In addition, we initiated a program to measure the Hugoniot data of heated samples to determine the Grüneisen parameter using a high-frequency inductive heating system. Detailed results for W, Cu, Au, etc. will be presented, and the resulting EOS and application as pressure standards will be discussed.

  9. High-Density Lipoprotein Cholesterol, Blood Urea Nitrogen, and Serum Creatinine Can Predict Severe Acute Pancreatitis

    Directory of Open Access Journals (Sweden)

    Wandong Hong

    2017-01-01

    Full Text Available Background and Aims. Early prediction of disease severity of acute pancreatitis (AP would be helpful for triaging patients to the appropriate level of care and intervention. The aim of the study was to develop a model able to predict Severe Acute Pancreatitis (SAP. Methods. A total of 647 patients with AP were enrolled. The demographic data, hematocrit, High-Density Lipoprotein Cholesterol (HDL-C determinant at time of admission, Blood Urea Nitrogen (BUN, and serum creatinine (Scr determinant at time of admission and 24 hrs after hospitalization were collected and analyzed statistically. Results. Multivariate logistic regression indicated that HDL-C at admission and BUN and Scr at 24 hours (hrs were independently associated with SAP. A logistic regression function (LR model was developed to predict SAP as follows: −2.25–0.06 HDL-C (mg/dl at admission + 0.06 BUN (mg/dl at 24 hours + 0.66 Scr (mg/dl at 24 hours. The optimism-corrected c-index for LR model was 0.832 after bootstrap validation. The area under the receiver operating characteristic curve for LR model for the prediction of SAP was 0.84. Conclusions. The LR model consists of HDL-C at admission and BUN and Scr at 24 hours, representing an additional tool to stratify patients at risk of SAP.

  10. Increased mortality in patients with severe COPD associated with high-intensity exercise

    DEFF Research Database (Denmark)

    Schaadt, Lone; Christensen, Robin; Kristensen, Lars Erik

    2016-01-01

    INTRODUCTION: Intensity of exercise is believed to be a key determinant of response to chronic obstructive pulmonary disease (COPD) rehabilitation. We hypothesized that a higher intensity of exercise, in combination with physiotherapist-led instructions and education in management of breathlessness...... prospective cohort study on severe COPD patients referred to outpatient rehabilitation. METHODS: In 2013, four rehabilitation courses were scheduled (spring, summer, autumn, and winter) each lasting 8 weeks and including eight to ten patients. This preliminary study was designed as a controlled cohort study...... assessed from the participants' medical records in an 18-month period. RESULTS: We were able to enroll 31 patients in total (15 in the high-intensity exercise group and 16 in regular intensity). There were no group differences in the hospitalization rates. However, during review of the medical records, we...

  11. [Autoimmune hypothyroidism nonresponsive to high doses of levothyroxine and severe hypocalcemia].

    Science.gov (United States)

    Silva, Cintia M dos Santos; Souza, Marcus Vinicius L de

    2005-08-01

    The factors that make difficult the normalization of TSH in hypothyroidism need special attention because some patients on thyroxine replacement do not maintain a normal TSH. We report a 50 year-old woman with autoimmune hypothyroidism of difficult compensation, associated with anemia, hypocalcemia with a previous episode of tetany, hypomagnesemia, psychologic alterations and important weight loss. After compensation of the hypothyroidism with doses of L-thyroxine as high as 325 microg/day, the hypothesis of a malabsorptive syndrome was raised. Celiac disease was confirmed by elevated serum antigliadin antibody. A gluten-free diet was instituted which improved the symptoms associated with malabsorption and reduced the L-thyroxine requirement to 125 microg/day. Because several studies have shown an association of both diseases, a routine screening for celiac disease has been widely proposed in patients with autoimmune thyroid disease.

  12. Microseismicity Induced by Fault Activation During the Fracture Process of a Crown Pillar

    Science.gov (United States)

    Zhang, Penghai; Yang, Tianhong; Yu, Qinglei; Xu, Tao; Zhu, Wancheng; Liu, Honglei; Zhou, Jingren; Zhao, Yongchuan

    2015-07-01

    Shirengou iron mine in Hebei Province, China is now under transition from open pit to underground mining. During this process, the unstable failure risk of crown pillar is growing as a result of underground mining, fault activation and water seepage. To monitor the stability of the crown pillar, a microseismic monitoring system was equipped in 2006. Based on temporal and spatial distribution of microseismic events and deformation mechanism, it was found that it is the propagation of the buried fault F15 that causes the failure of the crown pillar, resulting in increased water seeping into the underground drifts. By analyzing the temporal changes in multiple microseismic parameters during the fracture process of the crown pillar, it was found that several distinct abnormalities in the microseismic data such as a rapid decrease in the b value, a sharp increase in energy release, an abnormal increase in apparent stress and a low dominant frequency, could be judged as the signal of an increasing risk. Therefore, the microseismic monitoring has been proven to be a suitable method for understanding damage and fracture process of the crown pillar during the transition from open pit to underground mining.

  13. Modelling initial mortality of Abies religiosa in a crown fire in Mexico

    OpenAIRE

    Temiño Villota, Salomé; Rodríguez Trejo, Dante A.; Molina Terrén, Domingo; Ryan, Kevin C.

    2016-01-01

    Aim of study: The objectives of this work were to determine which morphological and fire severity variables may help explain the mortality of adult Abies religiosa (Kunth) Schltdl. & Cham., to model the probability of this species after being affected by crown fire, and to obtain more elements to classify the sacred fir in terms of fire resistance. This type of studies are relevant to estimate the impact of crown fires on the climax forests that forms this species.Area of study: The burne...

  14. Crowned Dens Syndrome: Report of Three Cases and a Review of the Literature.

    Science.gov (United States)

    Oka, Akihiko; Okazaki, Koichi; Takeno, Ayumu; Kumanomido, Satoshi; Kusunoki, Ryusaku; Sato, Shuichi; Ishihara, Shunji; Kinoshita, Yoshikazu; Nishina, Masayoshi

    2015-07-01

    Patients with crowned dens syndrome (CDS), which is pseudogout of the atlantoaxial junction induced by "crown-like" calcifications around the dens, present with symptoms of severe neck pain, rigidity, and high fever. CDS patients are often misdiagnosed as having meningitis or polymyalgia rheumatica, leading to potentially unnecessary invasive procedures for diagnosis and treatment. We report 3 patients with CDS who had characteristic findings on computed tomography (CT), all of whom quickly recovered with nonsteroidal antiinflammatory drug (NSAID) administration. In addition, we reviewed 72 published cases, including our patients. CDS typically occurs in elderly people (mean age 71.4 years). Common symptoms include neck pain (100%), neck rigidity (98%), and fever (80.4%), and most show elevated inflammatory markers (88.3%) on serum laboratory tests. Neck pain on rotation is a characteristic and helpful symptom in the diagnosis. The most useful modality is CT (97.1%), showing linear calcium deposits around the dens, mostly in the transverse ligament of atlas (TLA). CT number is especially helpful to distinguish a normal TLA (35-110 HU) from a calcified one (202-258 HU) in our cases. The most effective treatment is NSAID administration (85%), which usually leads to marked resolution of symptoms within days or weeks. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to acute and severe symptoms, CDS patients often present to an emergency department. To avoid unnecessary invasive procedures for diagnosis and treatment, CDS should be considered in the differential diagnosis of febrile neck pain. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Relationship between crown dieback and drought in the southeastern United States

    Science.gov (United States)

    Michael K. Crosby; Zhaofei Fan; Martin A. Spetich; Theodor D. Leininger; Xingang. Fan

    2012-01-01

    Forest Health and Monitoring (FHM) and Palmer's Drought Severity Index (PDSI) data were obtained for 11 states in the southeastern United States to assess the relationship between drought and crown dieback. Correlation analyses were performed at the species group and ecoregion levels within the study area. The results indicate a negative correlation between...

  16. Tree regeneration in black ash (Fraxinus nigra) stands exhibiting crown dieback in Minnesota

    Science.gov (United States)

    Brian J. Palik; Michael E. Ostry; Robert C. Venette; Ebrahim. Abdela

    2012-01-01

    Crown dieback and mortality of black ash (Fraxinus nigra) has been noted across the range of the species in North America for several decades. Causes of dieback and mortality are not definitive, but may be related to spring drought or excessive moisture. Where black ash is the dominant tree species in the forest, continued dieback and mortality may...

  17. Apical bud toughness tests and tree sway movements to examine crown abrasion: preliminary results

    Science.gov (United States)

    Tyler Brannon; Wayne Clatterbuck

    2012-01-01

    Apical bud toughness differences were examined for several species to determine if crown abrasion affects shoot growth of determinate and indeterminate species during stand development. Determinate buds will set and harden after initial shoot elongation in the spring, while the indeterminate shoots form leaves from the apical meristem continuously based on the...

  18. High incidence and severity of periodontitis in patients with Marfan syndrome in Japan.

    Science.gov (United States)

    Suzuki, Jun-Ichi; Imai, Yasushi; Aoki, Mieko; Fujita, Daishi; Aoyama, Norio; Tada, Yuko; Akazawa, Hiroshi; Izumi, Yuichi; Isobe, Mitsuaki; Komuro, Issei; Nagai, Ryozo; Hirata, Yasunobu

    2015-09-01

    Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the extracellular matrix protein fibrillin-1. While it is known that patients with MFS are at high risk of dental disorders and cardiovascular diseases, little information has been provided to date. To clarify the prevalence of periodontitis in patients with MFS, their oral condition and cardiovascular complications were evaluated. The subjects were patients with MFS (n = 40) who attended the University of Tokyo hospital; age- and gender-matched healthy individuals (n = 14) constituted a control group. Cardiovascular complications and full-mouth clinical measurements, including number of teeth, probing of pocket depth (PD), bleeding on probing (BOP), and community periodontal index (CPI) were recorded. MFS patients had more frequent cardiovascular complications (95 %) compared with the controls (0 %). MFS patients had periodontitis (CPI 3 and 4) more frequently (87.5 %) than the age- and gender-matched control subjects (35.7 %). Furthermore, MFS patients had significantly more severe periodontitis (CPI 2.90 ± 0.12 vs 1.64 ± 0.32) and fewer remaining teeth (26.7 ± 0.4 vs 28.4 ± 0.4) compared with the controls. However, PD and BOP were comparable between MFS patients and the control group. A high incidence of periodontitis and cardiovascular complications was observed in Japanese MFS patients.

  19. A simplified isolation technique for preparation and placement of resin composite strip crowns.

    Science.gov (United States)

    Psaltis, Gregory L; Kupietzky, Ari

    2008-01-01

    Resin composite strip crowns (SCs) have been utilized for over 2 decodes to restore carious primary teeth. While SCs are the most esthetic anterior crowns, they also are the most technique sensitive. Restoration of a severely decoyed primary anterior tooth with a SC restoration is often complicated by hemorrhage in the operative site. Inflamed, bleeding gingiva may interfere with proper curing of the restorations, resulting in discolored crowns due to excessive bleeding during the curing process. Proper isolation and hemostasis is crucial for successfully completing the SC restoration. Traditionally, the routine use of ligature ties to deflect gingival tissue and retain the rubber dam in place has been recommended to address this problem. The purpose of this report was to describe a simple, relatively inexpensive, alternative technique for placing SCs by utilizing orthodontic elastomers.

  20. Effect of preparation surface area on the clinical outcome of full veneer crowns in dogs.

    Science.gov (United States)

    Riehl, Jessica; Soukup, Jason W; Collins, Caitlyn; Siverling, Sarah; Ploeg, Heidi-Lynn; Snyder, Christopher J

    2014-01-01

    Crown therapy is commonly used in veterinary medicine to provide support to teeth which have previously fractured, received root canal therapy, have significant wear, or experienced other detrimental removal of tooth substance. As with several aspects of veterinary medicine, many of the recommendations or guidelines for crown therapy originate from human dentistry, which are then transferred to veterinary patients. Due to the significant difference in the anatomy of teeth and function of the oral cavity between humans and dogs, these guidelines need to be studied to determine the appropriateness of their use in veterinary patients. This article evaluates the relationship between surface area of the preparation and clinical outcome of full veneer crown therapy of the canine tooth in dogs. Although there appeared to be a positive relationship between preparations with greater surface area and successful clinical outcome, it was not found to be statistically significant.

  1. HURRICANE AND SEVERE STORM SENTINEL (HS3) HIGH-ALTITUDE IMAGING WIND AND RAIN AIRBORNE PROFILER (HIWRAP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) High-Altitude Imaging Wind and Rain dataset was collected from the High-altitude Imaging Wind and Rain Airborne...

  2. [A ten-year clinical study of cracked teeth restored with glass ceramic crowns].

    Science.gov (United States)

    Luo, X P; Yuan, Y; Shi, Y J; Qian, D D

    2016-10-09

    Objective: To evaluate the clinic performance of high strength glass ceramic crowns for the painful cracked teeth during a 10-year observation period. Methods: Forty-two posterior teeth from 36 patients were diagnosed as having a crack, biting painful and sensitivity to cold were selected in the Department of Prosthodontic, Institute and Hospital of Stomatology, Nanjing University Medical School. The lost-wax hot pressed glass ceramic crowns were bonded on the minimally invasive prepared teeth by modern adhesive technology. Patients were interviewed and went through clinic examination after one week, one month, and every six months. Results: The effectiveness of 42 glass ceramic crowns for cracked teeth was evaluated for a mean observation time over 10-year. At the first week, 29(81%) patients were free of pain, three still had sensitivity to cold and chewing pain, three still had sensitivity to cold, one had painful to cold and hot. After one month, two patients still had chewing pain, and one tooth needed endodontic treatment after six months. In 10 years, 2(5%) all ceramic crowns were broken, the other 40 restorations kept good clinical performances with a 10-year survival rate of 95%. Conclusions: The high strength glass ceramic crowns are very effective and successful in treating the cracked teeth and then keep the good mastication function and appearance.

  3. Clinical performance - a reflection of damage accumulation in ceramic dental crowns

    Energy Technology Data Exchange (ETDEWEB)

    Rekow, D.E. [Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States). Dept. of Orthodontics; Thompson, V.P. [Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States). New Jersey Dental School

    2001-07-01

    All-ceramic dental crowns have tremendous appeal for patients - their esthetics nearly match those of natural teeth. Unfortunately, the most esthetic materials are brittle and, consequently, are vulnerable to damage relating to shaping which is exacerbated during cyclic loading during normal chewing. Clinical performance of all-ceramic dental prostheses are directly dependent on damage introduced during fabrication and during fatigue loading associated with function. The accumulation of damage results in unacceptably high failure rates (where failure is defined as a complete fracture requiring replacement of the prosthesis). The relation between shaping damage and fatigue damage on clinical performance of all-ceramic dental crowns was investigated. Materials used commercially for all-ceramic crowns and investigated in this study included a series of different microstructures of machinable glass ceramics (Corning), aluminas and porcelains (Vita Zahnfabrik), and zirconia (Norton). As monolithic materials, strong, tough, fatigue-resistant materials are not sufficiently esthetic for crowns. Crowns fabricated from monolithic esthetic materials have high failure rates. Layering ceramics could provide acceptable strength through management of damage accumulation. (orig.)

  4. A guinea pig model of selective severe high-frequency hearing loss.

    Science.gov (United States)

    Havenith, Sarah; Klis, Sjaak F L; Versnel, Huib; Grolman, Wilko

    2013-10-01

    Using an appropriate dose of an aminoglycoside antibiotic cotreated with a loop diuretic a guinea pig model of high-frequency loss can be obtained mimicking cochlear implant candidates with low-frequency residual hearing. We examined the stability of this model over time. A well-established method to create an animal model for profound deafness is cotreatment with an aminoglycoside antibiotic and a loop diuretic. Recent data indicated that reduction of the aminoglycoside dose might yield selective high-frequency hearing loss. Such a model is relevant for studies related to hybrid cochlear implant devices, for example, with respect to preservation of residual hearing. Guinea pigs received an electrode for chronic recording of compound action potentials to tones to assess thresholds. They were treated with a coadministration of kanamycin (200 mg/kg) and furosemide (100 mg/kg), after which, the animals were sacrificed for histologic analysis at 2, 4, or 7 weeks. After 2 to 7 weeks threshold shifts were greater than 50 dB for 8 to 16 kHz in 15 of 17 animals, whereas threshold shifts at 2 kHz or lower were less than 50 dB in 13 animals. Major threshold shifts occurred the first 2 to 4 days; subsequently, some spontaneous recovery occurred and, after 2-3 weeks thresholds, remained stable. Inner hair cell loss still progressed between 2 and 4 weeks in the most basal cochlear region; thereafter, hair cell loss was stable. An appropriate animal model for selective severe high-frequency hearing loss was obtained, which is stable at 4 weeks after ototoxic treatment.

  5. Fracture resistance of monolithic zirconia molar crowns with reduced thickness.

    Science.gov (United States)

    Nakamura, Keisuke; Harada, Akio; Inagaki, Ryoichi; Kanno, Taro; Niwano, Yoshimi; Milleding, Percy; Örtengren, Ulf

    2015-01-01

    The purpose of the present study was to analyze the relationship between fracture load of monolithic zirconia crowns and axial/occlusal thickness and to evaluate the fracture resistance of monolithic zirconia crowns with reduced thickness in comparison with that of monolithic lithium disilicate crowns with regular thickness. Monolithic zirconia crowns (Lava Plus Zirconia, 3M/ESPE) with specified axial/occlusal thicknesses and lithium disilicate crowns (IPS e.max press, Ivoclar/Vivadent) with regular thickness were fabricated using a dental CAD/CAM system and a press technique, respectively. The crowns cemented onto dies were loaded until fracture. Based on measurements of the crown thickness made by micro-CT and the fracture load, multiple regression analysis was performed. It was revealed that the occlusal thickness significantly affected the fracture load (p zirconia crowns, the fracture load of the zirconia crowns with the occlusal thickness of 0.5 mm (5558 ± 522 N) was significantly higher than that of lithium disilicate crowns with an occlusal thickness of 1.5 mm (3147 ± 409 N). Within the limitations of the present study, it is suggested that monolithic zirconia crown with chamfer width of 0.5 mm and occlusal thickness of 0.5 mm can be used in the molar region in terms of fracture resistance.

  6. Tree Crown Mapping in Managed Woodlands (Parklands) of Semi-Arid West Africa Using WorldView-2 Imagery and Geographic Object Based Image Analysis

    Science.gov (United States)

    Karlson, Martin; Reese, Heather; Ostwald, Madelene

    2014-01-01

    Detailed information on tree cover structure is critical for research and monitoring programs targeting African woodlands, including agroforestry parklands. High spatial resolution satellite imagery represents a potentially effective alternative to field-based surveys, but requires the development of accurate methods to automate information extraction. This study presents a method for tree crown mapping based on Geographic Object Based Image Analysis (GEOBIA) that use spectral and geometric information to detect and delineate individual tree crowns and crown clusters. The method was implemented on a WorldView-2 image acquired over the parklands of Saponé, Burkina Faso, and rigorously evaluated against field reference data. The overall detection rate was 85.4% for individual tree crowns and crown clusters, with lower accuracies in areas with high tree density and dense understory vegetation. The overall delineation error (expressed as the difference between area of delineated object and crown area measured in the field) was 45.6% for individual tree crowns and 61.5% for crown clusters. Delineation accuracies were higher for medium (35–100 m2) and large (≥100 m2) trees compared to small (crown mapping in parkland landscapes and similar woodland areas. PMID:25460815

  7. Cerec anterior crowns: restorative options with monolithic ceramic materials.

    Science.gov (United States)

    Reich, Sven; Fiedlar, Kurt

    2013-01-01

    The aim of this article is to discuss the different types of monolithic ceramic crowns that can be placed on anterior teeth with existing shoulder preparations. Anterior crowns were indicated for the teeth 12 to 22 in the present case. The patient, a 65-year-old male, had received all-ceramic crowns 20 years earlier, which had started to develop cracks and palatal fractures over the last few years. The patient's teeth were prepared and four sets of crowns were fabricated using different monolithic ceramic materials: IPS e.max CAD, Cerec Blocs C In, VITABLOCS Real Life, and ENAMIC. Both shade characterization and crystallization firing were performed on the monolithic lithium disilicate glass ceramic crowns. The silicate ceramic crowns received glaze firing alone. The crowns made of hybrid ceramic (ENAMIC) were treated with a polymer sealant.

  8. [Transvaginal Prosima mesh and high uterosacral ligament suspension in the treatment of severe pelvic organ prolapsey].

    Science.gov (United States)

    Wang, Wen-ying; Lu, Yong-xian; Hu, Xiao-juan; Liu, Xin; Shen, Wen-jie; Liu, Jing-xia; Ge, Jing; Zhang, Ying-hui; Zhao, Ying; Niu, Ke

    2012-07-01

    To study the efficacy of performing transvaginal Prosima mesh with high uterosacral ligament suspension (HUS) in treatment of severe pelvic organ prolapse (POP). From July 2010 to February 2011, 70 patients with severe POP underwent transvaginal prosima mesh with HUS in First Affiliated Hospital, General Hospital of People's Liberation Army. Clinical parameters of perioperation were collected. After 1 month and 2 - 3 months, perineal two-dimensional ultrasound examination was performed to measure mesh length in midsagittal plane. Validated prolapse quality of life questionnaires, pelvic floor distress inventsry short form 20 (PFDI-20) and pelvic floor impact questionnaire short form 7 (PFIQ-7) were used to evaluate the therapeutic effect. The mean results of pre-operative PFIQ-7 and PFDI-20 was 54 and 51, respectively. Median operation time was (195 ± 47) min and median blood loss was (160 ± 64) ml. All the patients were followed for a mean time of 13 months (2 - 19 months). Seven cases were found with mesh exposure with less than 1 cm(2). The objective cure rate was 100%. The mean score of post-operative PFIQ-7 and PFDI-20 were both 19, which were significantly lower than those of pre-operation (P < 0.05). Anterior Prosima mesh was 3.5 cm at 1 month by ultrasound examination, and the second result of ultrasound scans was 2.8 cm at 2 - 3 month, which were both shortened 2.5 cm and 3.2 cm when compared with that of original size. Transvaginal Prosima mesh placement with HUS is a safe and efficient surgery with less complication. Although mesh became shorter after 2 - 3 month, it did not affect surgery efficacy.

  9. Pediatric Preformed Metal Crowns - An Update

    OpenAIRE

    Sangameshwar Sajjanshetty; P S Patil; Deepa Hugar; K Rajkumar

    2013-01-01

    Stainless Steel crowns (SSC) were introduced in 1947 by the Rocky Mountain Company and popularized by Humphrey in 1950. Prefabricated SSC can be adapted to individual primary teeth and cemented in place to provide a definitive restoration. The SSC is extremely durable, relatively inexpensive, subject to minimal technique sensitivity during placement, and offers the advantage of full coronal coverage. SSC are often used to restore primary and permanent teeth in children and adolescents where i...

  10. Plasma high sensitivity C-reactive protein as a marker of severity in ...

    African Journals Online (AJOL)

    severe DKA (p value for both <0.001). Hs-CRP was strongly associated with IL6 level and WBCs count in moderate /severe DKA. Conclusion: Hs-CRP is increased in moderate/severe DKA patients along with IL6 and leukocytes in absence of ...

  11. Alkaline-side extraction of technetium from tank waste using crown ethers and other extractants

    Energy Technology Data Exchange (ETDEWEB)

    Bonnesen, P.V.; Moyer, B.A.; Presley, D.J.; Armstrong, V.S.; Haverlock, T.J.; Counce, R.M.; Sachleben, R.A.

    1996-06-01

    The chemical development of a new crown-ether-based solvent-extraction process for the separation of (Tc) from alkaline tank-waste supernate is ready for counter-current testing. The process addresses a priority need in the proposed cleanup of Hanford and other tank wastes. This need has arisen from concerns due to the volatility of Tc during vitrification, as well as {sup 99}Tc`s long half-life and environmental mobility. The new process offers several key advantages that direct treatability--no adjustment of the waste composition is needed; economical stripping with water; high efficiency--few stages needed; non-RCRA chemicals--no generation of hazardous or mixed wastes; co-extraction of {sup 90}Sr; and optional concentration on a resin. A key concept advanced in this work entails the use of tandem techniques: solvent extraction offers high selectivity, while a subsequent column sorption process on the aqueous stripping solution serves to greatly concentrate the Tc. Optionally, the stripping solution can be evaporated to a small volume. Batch tests of the solvent-extraction and stripping components of the process have been conducted on actual melton Valley Storage Tank (MVST) waste as well as simulants of MVST and Hanford waste. The tandem process was demonstrated on MVST waste simulants using the three solvents that were selected the final candidates for the process. The solvents are 0.04 M bis-4,4{prime}(5{prime})[(tert-butyl)cyclohexano]-18-crown-6 (abbreviated di-t-BuCH18C6) in a 1:1 vol/vol blend of tributyl phosphate and Isopar{reg_sign} M (an isoparaffinic kerosene); 0.02 M di-t-BuCH18C6 in 2:1 vol/vol TBP/Isopar M and pure TBP. The process is now ready for counter-current testing on actual Hanford tank supernates.

  12. On the radiation stability of crown ethers in ionic liquids.

    Energy Technology Data Exchange (ETDEWEB)

    Shkrob, I.; Marin, T.; Dietz, M. (Chemical Sciences and Engineering Division); (Benedictine Univ.); (Univ. of Wisconsin at Milwaukee)

    2011-04-14

    Crown ethers (CEs) are macrocyclic ionophores used for the separation of strontium-90 from acidic nuclear waste streams. Room temperature ionic liquids (ILs) are presently being considered as replacements for traditional molecular solvents employed in such separations. It is desirable that the extraction efficacy obtained with such solvents should not deteriorate in the strong radiation fields generated by decaying radionuclides. This deterioration will depend on the extent of radiation damage to both the IL solvent and the CE solute. While radiation damage to ILs has been extensively studied, the issue of the radiation stability of crown ethers, particularly in an IL matrix, has not been adequately addressed. With this in mind, we have employed electron paramagnetic resonance (EPR) spectroscopy to study the formation of CE-related radicals in the radiolysis of selected CEs in ILs incorporating aromatic (imidazolium and pyridinium) cations. The crown ethers have been found to yield primarily hydrogen loss radicals, H atoms, and the formyl radical. In the low-dose regime, the relative yield of these radicals increases linearly with the mole fraction of the solute, suggesting negligible transfer of the excitation energy from the solvent to the solute; that is, the solvent has a 'radioprotective' effect. The damage to the CE in the loading region of practical interest is relatively low. Under such conditions, the main chemical pathway leading to decreased extraction performance is protonation of the macrocycle. At high radiation doses, sufficient to increase the acidity of the IL solvent significantly, such proton complexes compete with the solvent cations as electron traps. In this regime, the CEs will rapidly degrade as the result of H abstraction from the CE ring by the released H atoms. Thus, the radiation dose to which a CE/IL system is exposed must be maintained at a level sufficiently low to avoid this regime.

  13. Asymmetric catalysis in aqueous media: use of metal-chiral crown ethers as efficient chiral Lewis acid catalysts in asymmetric aldol reactions

    Directory of Open Access Journals (Sweden)

    Shu Kobayashi

    2001-01-01

    Full Text Available Metal-chiral crown ether complexes have been developed as efficient chiral Lewis acid catalysts for asymmetric aldol reactions of silyl enol ethers with aldehydes in aqueous media. While many excellent catalytic asymmetric reactions have been developed recently, most of them have to be carried out under strictly anhydrous conditions in organic solvents. This is probably due to the instability of many catalysts and/or intermediates in the presence of even a small amount of water. To address this issue, we searched for metal-crown ether complexes on the basis of our "multi-coordination" hypothesis, and found that lead(II and lanthanide(III catalysts worked well as chiral Lewis acids in aqueous media. To the best of our knowledge, these are the first examples of chiral crown-based Lewis acids that can be successfully used in catalytic asymmetric reactions. The catalysts have been characterized by X-ray diffraction, and their unique structures as chiral catalysts have been revealed. Use of water as a solvent is essential in these asymmetric catalysis, and the role of water on these reactions to explain the high reactivity and selectivity has been suggested. Another important point is that kinetic studies have shown the possibility that these types of crown ether complexes would be suitable as chiral catalysts employed in aqueous media. In addition, although the catalytic asymmetric aldol reactions are one of the most powerful carbon-carbon bond-forming methodologies and several successful examples have been reported, the use of aprotic anhydrous solvents and low reaction temperatures (-78 °C has been needed in almost all successful cases. On the other hand, the present reactions proceeded smoothly at -10-0 °C in water-alcohol solutions while retaining high levels of diastereo- and enantioselectivities.

  14. High-frequency measurement of depressive severity in a patient treated for severe treatment-resistant depression with deep-brain stimulation.

    Science.gov (United States)

    Sani, S; Busnello, J; Kochanski, R; Cohen, Y; Gibbons, R D

    2017-08-15

    Although there have been previous studies of deep-brain stimulation (DBS), we present, to our knowledge, the first example of high-frequency depressive severity measurement-based DBS treatment in particular and psychiatric treatment in general. Daily post-surgical e-mail prompts for a period of 6 months resulted in 93 administrations of a computerized adaptive test (CAT) of depression severity (CAT-Depression Inventory or CAT-DI) via the internet. There was an average of 3.37 weekly measurements with an average separation of 2.12 days. No additional incentive was provided to the patient for completing the adaptive tests. The patient is a 55-year-old female with six psychiatric hospitalizations for depression, two suicide attempts, marginal response to eight electroconvulsive therapy (ECT) treatments and 35 psychotropic medications. We report results after high-frequency stimulation of the superolateral branch of the medial forebrain bundle. The CAT-DI was used for daily assessments before, during and after (remotely in response to an e-mail prompt) the DBS procedure. Two follow-up Hamilton Depression Scales (HAM-Ds) were also collected. Response to treatment varied markedly, with a decrease from severe (>75) to mild (60), which is three times the size of the uncertainty level. Although the HAM-D scores decreased, they missed the more complete temporal pattern identified by CAT-DI daily monitoring. We demonstrated feasibility of daily depressive severity measurement at high levels of precision and compliance. Clinician ratings confirm the general pattern of treatment benefit, but mask the marked variability in mood and more marked periods of benefit and decline.

  15. URS Brava – a new oat cultivar with partial resistance to crown rust

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Federizzi

    2015-08-01

    Full Text Available The cultivar URS Brava, obtained from a simple cross between the line ‘UFRGS 995078-2’ and the cultivar ‘URS 21’, shows high grain yield and stability, high grain quality, desirable agronomical traits and partial resistance to crown rust, caused by the fungus Puccinia coronata f. sp. avenae.

  16. Severe water ingress accident analysis for a Modular High Temperature Gas Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zuoyi [Inst. of Nuclear Energy Technology Tsinghua Univ., Beijing, BJ (China); Scherer, Winfried

    1997-12-31

    This paper analyzes the severe water ingress accidents in the SIEMENS 200MW Modular High Temperature Gas Cooled Reactor (HTR-Module) under the assumption of no active safety protection systems in order to find the safety margin of the current HTR-Module design. A water, steam and helium multi-phase cavity model is originally developed and implemented in the DSNP simulation system. The developed DSNP system is used to simulate the primary circuit of HTR-Module power plant. The comparisons of the models with the TINTE calculations validate the current simulation. After analyzing the effects of blower separation on water droplets, the wall heat storage, etc., it is found that the maximum H{sub 2}O density increase rate in the reactor core is smaller than 0.3 kg/(m{sup 3}s). The liquid water vaporization in the steam generator and H{sub 2}O transport from the steam generator to the reactor core reduces the impulse of the H{sub 2}O in the reactor core. The nuclear reactivity increase caused by the water ingress leads to a fast power excursion, which, however, is inherently counterbalanced by negative feedback effects. Concerning the integrity of the fuel elements, the safety relevant temperature limit of 1600degC was not reached in any case. (author)

  17. Evaluation of the stress corrosion cracking resistance of several high strength low alloy steels

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The stress corrosion cracking resistance was studied for high strength alloy steels 4130, 4340, for H-11 at selected strength levels, and for D6AC and HY140 at a single strength. Round tensile and C-ring type specimens were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, salt spray, the atmosphere at Marshall Space Flight Center, and the seacoast at Kennedy Space Center. Under the test conditions, 4130 and 4340 steels heat treated to a tensile strength of 1240 MPa (180 ksi), H-11 and D6AC heat treated to a tensile strength of 1450 MPa (210 ksi), and HY140 (1020 MPa, 148 ksi) are resistant to stress corrosion cracking because failures were not encountered at stress levels up to 75 percent of their yield strengths. A maximum exposure period of one month for alternate immersion in salt water or salt spray and three months for seacoast is indicated for alloy steel to avoid false indications of stress corrosion cracking because of failure resulting from severe pitting.

  18. FEM and Von Mises Analysis on Prosthetic Crowns Structural Elements: Evaluation of Different Applied Materials

    Directory of Open Access Journals (Sweden)

    Ennio Bramanti

    2017-01-01

    Full Text Available The aim of this paper is to underline the mechanical properties of dental single crown prosthodontics materials in order to differentiate the possibility of using each material for typical clinical condition and masticatory load. Objective of the investigation is to highlight the stress distribution over different common dental crowns by using computer-aided design software and a three-dimensional virtual model. By using engineering systems of analyses like FEM and Von Mises investigations it has been highlighted the strength over simulated lower first premolar crowns made by chrome cobalt alloy, golden alloy, dental resin, and zirconia. The prosthodontics crown models have been created and put on simulated chewing stresses. The three-dimensional models were subjected to axial and oblique forces and both guaranteed expected results over simulated masticatory cycle. Dental resin presented the low value of fracture while high values have been recorded for the metal alloy and zirconia. Clinicians should choose the better prosthetic solution for the teeth they want to restore and replace. Both prosthetic dental crowns offer long-term success if applied following the manufacture guide limitations and suggestions.

  19. Allergic contact gingivostomatitis from a temporary crown made of methacrylates and epoxy diacrylates.

    Science.gov (United States)

    Kanerva, L; Alanko, K; Estlander, T

    1999-12-01

    Occupational allergic contact dermatitis caused by (meth)acrylates is common in dental personnel, whereas dental acrylic fillings and crowns have rarely been reported to cause problems in dental patients. Here we report on a 48-year-old woman who developed gingivitis, stomatitis, and perioral dermatitis after a temporary crown made of restorative, two-component material had been inserted. The manufacturer stated that the temporary crown base paste and catalyst contained three (meth)acrylates, namely, a proacrylate, which is a modification of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (BIS-GMA); a tricyclate, which is a saturated, aliphatic, tricyclic methacrylate; and urethane methacrylate. The manufacturer refused to give more exact information on the (meth)acrylates. Patch testing revealed that the patient was highly allergic to BIS-GMA, other epoxy diacrylates, and (meth)acrylates, as well as to the base paste and catalyst of the temporary crown. Accordingly, it was concluded that the allergic reaction was caused by BIS-GMA, or a cross-reacting (meth)acrylate, or other (meth)acrylates in the temporary crown.

  20. Color change and fracture resistance of two preveneered stainless-steel crowns after sterilization.

    Science.gov (United States)

    Wickersham, G T; Seale, N S; Frysh, H

    1998-01-01

    This study compared the fracture resistance and color stability of two commercially available, preveneered stainless-steel crowns before and after four sterilization techniques. Thirty-five crowns from each of two manufacturers were divided into five groups. Four groups were sterilized twice using one of the following techniques: steam autoclave at both 121 degrees C (15 PSI) for 20 min and 132 degrees C (30 PSI) for 8 min; Chemiclave with formaldehyde at 132 degrees C for 20 min; and 2% gluteraldehyde for 10 h. The fifth group from each manufacturer was the control. Color of facings was measured before and after each sterilization in triplicate using a colorimeter, and the variance of each color parameter was analyzed for significance. Fracture resistance was measured for each group and differences between the control and experimental groups analyzed for significance. The results of this study show that high heat and chemical sterilizations have little effect on color and fracture resistance of the preveneered stainless-steel crowns. Student's t test analysis revealed a significantly decreased resistance to fracture with Kinder Krowns sterilized in 2% gluteraldehyde. Chemiclave sterilization caused the most negative color change in all three color parameters measured for both types of crowns. As neither steam technique produced significant changes in fracture resistance or color changes that were clinically detectable, the results of this study indicate that the two steam techniques tested can be used by clinicians to sterilize either Kinder Krowns or Nu Smile preveneered stainless-steel crowns.

  1. Engineering of surface microstructure transformations using high rate severe plastic deformation in machining

    Science.gov (United States)

    Abolghasem, Sepideh

    research effort, where Large Strain Machining (LSM) is presented as a controlled test of microstructure response. Sample conditions are created using LSM in Face Centered Cubic (FCC) metals, while characterizing the deformation using Digital Image Correlation(DIC) and Infrared(IR) thermography. Microstructural consequences such as grain size, subgrain size and grain boundary responses resulting from the characterized thermomechanical conditions are examined using Electron Back-Scattered Diffraction (EBSD). Once empirical data is generated across the broad thermomechanical conditions, reliable microstructure maps are populated. This characterization can help understand surface microstructures resulting from shear-based manufacturing processes such as turning, milling, shaping, etc. that are created under analogous thermomechanical conditions. Keywords: microstructure characterization, ultrafine grain microstructure, severe plastic deformation, high speed deformation.

  2. Severe maternal morbidity associated with maternal birthplace in three high-immigration settings

    DEFF Research Database (Denmark)

    Urquia, Marcelo L; Glazier, Richard H; Mortensen, Laust

    2015-01-01

    BACKGROUND: Maternal mortality and morbidity vary substantially worldwide. It is unknown if these geographic differences translate into disparities in severe maternal morbidity among immigrants from various world regions. We assessed disparities in severe maternal morbidity between immigrant wome......-Saharan Africans in all three settings. CONCLUSIONS: Immigrant women from Sub-Saharan Africa have higher rates of severe maternal morbidity. Other immigrant groups had similar or lower rates than the majority locally born populations....

  3. Crown plasticity and competition for canopy space: a new spatially implicit model parameterized for 250 North American tree species.

    Directory of Open Access Journals (Sweden)

    Drew W Purves

    Full Text Available BACKGROUND: Canopy structure, which can be defined as the sum of the sizes, shapes and relative placements of the tree crowns in a forest stand, is central to all aspects of forest ecology. But there is no accepted method for deriving canopy structure from the sizes, species and biomechanical properties of the individual trees in a stand. Any such method must capture the fact that trees are highly plastic in their growth, forming tessellating crown shapes that fill all or most of the canopy space. METHODOLOGY/PRINCIPAL FINDINGS: We introduce a new, simple and rapidly-implemented model--the Ideal Tree Distribution, ITD--with tree form (height allometry and crown shape, growth plasticity, and space-filling, at its core. The ITD predicts the canopy status (in or out of canopy, crown depth, and total and exposed crown area of the trees in a stand, given their species, sizes and potential crown shapes. We use maximum likelihood methods, in conjunction with data from over 100,000 trees taken from forests across the coterminous US, to estimate ITD model parameters for 250 North American tree species. With only two free parameters per species--one aggregate parameter to describe crown shape, and one parameter to set the so-called depth bias--the model captures between-species patterns in average canopy status, crown radius, and crown depth, and within-species means of these metrics vs stem diameter. The model also predicts much of the variation in these metrics for a tree of a given species and size, resulting solely from deterministic responses to variation in stand structure. CONCLUSIONS/SIGNIFICANCE: This new model, with parameters for US tree species, opens up new possibilities for understanding and modeling forest dynamics at local and regional scales, and may provide a new way to interpret remote sensing data of forest canopies, including LIDAR and aerial photography.

  4. An Investigation Into the Integrity of Fit of Provisional Crowns Using Current Proprietary Temporary Crown Materials.

    Science.gov (United States)

    Taylor, Philip D; Georgakis, Georgios; Niggli, Jason

    2016-06-01

    Three methods of direct provisional crown construction were investigated for accuracy of marginal fit. A modified proprietary crown coping was compared to Bis GMA and isobutyl methacrylate resin provisional crowns with margins modified by using a flowable composite and 'bead on' isobutyl methacrylate respectively. Measurement was at 50x magnification at seven sites over the fit surface. Data was analyzed using SPSS version 13.0.1 and measurement compared using the Mann Whitney test set at a significance level of 0.05. Reliability was checked using the Bland Altman test. Statistical significant differences were found between the three groups. The order of best fit was Bis-GMA and flowable composite > isobutyl methacrylate with 'bead on' margins > Bis-GMA modified implant temporary coping. The clinical significance is that the Bis GMA and flowable composite combination can be used with equal confidence to traditional methods of temporarisation.

  5. Posterior preveneered stainless steel crowns: clinical performance after three years.

    Science.gov (United States)

    O'Connell, Anne C; Kratunova, Evelina; Leith, Rona

    2014-01-01

    The purpose of this study was to evaluate the clinical performance of posterior preveneered stainless steel crowns after three years. NuSmile crowns and Kinder Krowns were randomly allocated on paired molars using a split-mouth design. Variables such as fracture, wear, gingival health, and esthetics were recorded. (PStatistical analysis was completed on 34 paired crowns in 14 children. After three years, 53 percent of crowns were fracture free compared to 81 percent at one year. There was minimal esthetic impact for most fractures due to the location of the veneer fracture, but five crowns had extensive fracture. No difference was reported in the clinical performance between the two crown types. Fracture was more likely to occur where the adjacent tooth was missing. Parents reported a satisfaction rating of 8.3 out of 10. Clinical performance of both crown types was similar and successful for three years. Facing fracture occurred in 47 percent of crowns but had minimal impact on the esthetic value or parental satisfaction in the majority of cases. These crowns offer an esthetic alternative to the traditional stainless steel crown, but parents should be alerted to the possibility of veneer loss over time.

  6. Veneer retention of preveneered primary stainless steel crowns after crimping.

    Science.gov (United States)

    Gupta, Monica; Chen, Jung-Wei; Ontiveros, Joe C

    2008-01-01

    The purpose of this study was to determine if crimping the lingual aspect of commercially available, preveneered, anterior stainless steel primary crowns affects the fracture resistance of the veneer facings. Twenty-six anterior NuSmile crowns (size A1) were divided into 2 groups: group 1 served as the control, and group 2 was manually crimped evenly on the lingual cervical portion. All crowns were cemented onto a screw-mounted resin core duplicated from a manually prepared Kilgore tooth and tested under compression. Recorded were fracture resistance, percent of veneer facing loss, and fracture to the gingival margin. Differences between the control and experimental groups were analyzed by independent t test and chi-square (alpha=0.05). The mean shear force required to fracture the veneers of the noncrimped crowns was 510.11 N (+/-79.66 SD), and 511.02 N (+/-62.37) for the crimped crowns. The mean percentage of veneer facing removed in the noncrimped crowns was 33% (+/-12.18), and 43% (+/-14.30) in the crimped crowns. No significant difference in shear strengths (P=.970) and in percentage of veneer loss (P=.063) was shown between crimped and noncrimped crowns. A mean of 8% of the noncrimped crowns and 23% of the crimped crowns had veneers fracturing to the gingival margin. The chi-square test showed no significant difference (P=.297). The veneer resistance to fracture for the crimped crowns was comparable to noncrimped crowns. The crimped crowns, however, were associated with greater veneer surface area loss.

  7. High hip fracture risk in men with severe aortic calcification - MrOS study

    Science.gov (United States)

    Szulc, Pawel; Blackwell, Terri; Schousboe, John T.; Bauer, Douglas C.; Cawthon, Peggy; Lane, Nancy E.; Cummings, Steven R.; Orwoll, Eric S.; Black, Dennis M.; Ensrud, Kristine E.

    2013-01-01

    A significant link between cardiovascular disease and osteoporosis is established in postmenopausal women, but data in men are scarce. We tested the hypothesis that greater severity of abdominal aortic calcification (AAC) was associated with an increased risk of non-spine fracture in 5994 men aged ≥65 years. AAC wasassessed on 5400 baseline lateral thoraco-lumbar radiographs using a validated visual semi-quantitative score. Total hip bone mineral density (BMD) was measured using dual energy X-ray absorptiometry. Incident non-spine fractures were centrally adjudicated. After adjustment for age, BMI, total hip BMD, fall history, prior fracture, smoking status, co-morbidities, race and clinical center, the risk of non-spine fracture (n=805) was increased among men with higher AAC (HR Q4 (AAC score ≥9) vs Q1 (0-1): 1.36, 96%CI: 1.10-1.68). This association was due to an increased risk of hip fracture (n=178) among men with higher AAC (HR Q4 vs Q1: 2.33, 95%CI: 1.41-3.87). By contrast, the association between AAC and the risk of non-spine-non-hip fracture was weaker and not significant (HR Q4 vs Q1: 1.22, 95%CI: 0.96-1.55). The findings regarding higher AAC and increased risk of fracture were not altered in additional analyses accounting for degree of trauma, estimated glomerular filtration rate, presence of lumbar vertebral fractures (which may bias AAC assessment), preexisting cardiovascular disease, ankle brachial index or competing risk of death. Thus, in this large cohort of elderly men, greater AAC was independently associated with an increased risk of hip fracture, but not with other non-spine fractures. These findings suggest that AAC assessment may be a useful method for identification of older men at high risk of hip fracture. PMID:23983224

  8. Severe dating violence and quality of life among south carolina high school students.

    Science.gov (United States)

    Coker, A L; McKeown, R E; Sanderson, M; Davis, K E; Valois, R F; Huebner, E S

    2000-11-01

    Little research has addressed the impact of dating violence and forced-sex victimization and perpetration on adolescent well-being. In this cross-sectional study, we provide (1) estimates of severe dating violence (SDV) by victimization and perpetration status, (2) estimates of lifetime forced-sex victimization and perpetration, (3) demographic and health behaviors correlated with SDV, and (4) associations between SDV and forced sex and well-being as assessed by (1) health-related quality of life (H-R QOL) and (2) life satisfaction measures. We used a stratified cluster sample of 5414 public high school students, grades 9 through 12, who responded to the 1997 self-administered South Carolina Youth Risk Behavior Survey. Nearly 12% of adolescents self-reported SDV as a victim (7.6%) or a perpetrator (7.7%), and SDV rates (victimization/perpetration combined) are higher in girls (14.4%) than boys (9.1%). Race, aggressive behaviors, substance use, and sexual risk-taking are correlates of SDV. Among young women, SDV victimization, not perpetration, was associated with recent poor H-R QOL and suicide ideation or attempts, but not lower life-satisfaction scores. Among young men, SDV perpetration, not victimization, was strongly associated with poor H-R QOL and suicide attempts, and lower scores for all domains of life satisfaction. This research provides evidence that SDV and forced sex are associated with poor H-R QOL, low life-satisfaction scores, and adverse health behaviors in adolescent female victims and male perpetrators. Screening for dating violence is needed to identify and intervene early to reduce the impact of dating violence.

  9. Dynamics of the MAP IOP 15 severe Mistral event: Observations and high-resolution numerical simulations

    Science.gov (United States)

    Guénard, V.; Drobinski, P.; Caccia, J. L.; Tedeschi, G.; Currier, P.

    2006-04-01

    This paper investigates the fundamental processes involved in a severe Mistral event that occurred during the Mesoscale Alpine Program (from 6 to 9 November 1999). The Mistral refers to a violent north/north-westerly wind blowing in south-eastern France from the Rhône valley to the French Riviera. The study is based on measurements from radiosoundings launched from Lyon and Nîmes and from two UHF wind profilers located near Marseille and Toulon allowing a good description of the flow in the complex terrain formed by the south-western Alps. Observational results are compared with RAMS non-hydrostatic numerical simulations performed with 27 km, 9 km and 3 km nested grids. The numerical simulations capture the flow complexity both upstream of the Alps and in the coastal area affected by the Mistral. They correctly reproduce horizontal wind speeds and directions, vertical velocities, virtual potential temperature and relative humidity documented by the observational network. The simulations are used to point out the main dynamical processes generating the Mistral. It is found that flow splitting around the Alps and around the isolated peaks bordering the south-eastern part of the Rhône valley (Mont Ventoux 1909 m, Massif du Lubéron 1425 m) induces the low-level jet observed near Marseille that lasts for 36 hours. The high-resolution simulation indicates that the transient low-level jet lasting for only 9 hours observed at Toulon is due to a gravity wave breaking over local topography (the Sainte Baume 1147 m) where hydraulic jumps are involved. A mountain wake with two opposite-sign potential-vorticity banners is generated. The mesoscale wake explains the westward progression of the large-scale Alpine wake.

  10. Rational Design of Cesium-Selective Ionophores and Chemosensors: Dihydrocalix[4]arene Crown-6 Ethers

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, Richard A.; Bryan, Jeffrey C.; Brown, Gilbert M.; Engle, Nancy L.; Haverlock, Tamara J.; Hay, Benjamin P.; Urvoas, Agathe; Moyer, Bruce A.

    2003-12-15

    Molecular mechanics calculations performed on calix[4]arene crown-6 ethers predict that the 1,3-dihydro derivatives will exhibit greater complementarity for potassium and cesium ions than the parent 1,3-dialkoxy calix crowns. The X-ray crystal structures of 1,3-alt bis-octyloxycalix[4]arene benzocrown-6 ether, dihydrocalix[4]arene benzocrown-6 ether, and the cesium nitrate complex of dihydrocalix[4]arene benzocrown-6 ether were determined. The cesium complex structure corresponds closely to the structure predicted by molecular mechanics. The dihydrocalix[4]arene crown-6 ethers exhibit enhanced cesium selectivity in the extraction of alkali metal salts and provide a platform for a highly sensitive and selective cesium chemosensor.

  11. Vonlays: a conservative esthetic alternative to full-coverage crowns.

    Science.gov (United States)

    McLaren, Edward A; Figueira, Johan; Goldstein, Ronald E

    2015-04-01

    Porcelain veneers have long been a popular restorative option that have evolved into a well-accepted treatment that can be fabricated in various ways. Onlays are another common treatment modality used in contemporary dentistry to restore large areas of decay and to replace old restorations. With the availability of newer high-strength materials such as lithium disilicate and processing technologies like CAD/CAM and heat pressing, dental professionals are now able to produce highly esthetic, high-strength restorations that blend seamlessly with the natural dentition while also withstanding posterior occlusal forces. This has resulted in innovative methods of providing minimally invasive dentistry. One such approach is a combination restoration the authors call a "vonlay," which, as demonstrated in this case report, can be used as an alternative to coverage crowns to restore damaged posterior teeth.

  12. High prevalence of seasonal affective disorder among persons with severe visual impairment

    DEFF Research Database (Denmark)

    Madsen, Helle Østergaard; Dam, Henrik; Hageman, Ida

    2016-01-01

    BACKGROUND: Light severely affects the occurrence of seasonal affective disorder (SAD). AIMS: To compare the prevalence of SAD in persons with severe visual impairment and persons with full sight, and in persons with severe visual impairment with or without light perception. METHOD: This cross......-sectional study assessed the Global Seasonality Score (GSS) and the prevalence of SAD among 2781 persons with visual impairment and 4099 persons with full sight using the Seasonal Pattern Assessment Questionnaire (SPAQ). RESULTS: Respondents with visual impairment had significantly higher GSS and prevalence...... of SAD compared with full sight controls, PSAD parameters...

  13. [Comparison of the clinical effects of selective laser melting deposition basal crowns and cobalt chromium alloy base crowns].

    Science.gov (United States)

    Li, Jing-min; Wang, Wei-qian; Ma, Jing-yuan

    2014-06-01

    To evaluate the clinical effects of selective laser melting (SLM) deposition basal crowns and cobalt chromium alloy casting base crowns. One hundred and sixty eight patients treated with either SLM deposition basal crowns (110 teeth) or cobalt chromium alloy casting basal crowns (110 teeth) were followed-up for 1 month, 6 months, 12 months and 24 months. The revised standard of American Public Health Association was used to evaluate the clinical effect of restoration, including the color of porcelain crowns, gingival inflammation, gingival margin discoloration, and crack or fracture. Data analysis was conducted with SPSS 20 software package for Student's t test and Chi-square test. Six cases were lost to follow-up. The patients who were treated with SLM deposition basal crowns (104 teeth) and cobalt chromium alloy casting base crowns (101 teeth) completed the study. Patients were more satisfied with SLM deposition cobalt chromium alloy porcelain crowns. There was 1 prosthesis with poor marginal fit after 24 months of restoration in SLM crowns. There were 6 prostheses with edge coloring and 8 with poor marginal fit in cobalt chromium alloy casting base crowns, which was significantly different between the 2 groups(P<0.05). The SLM deposition copings results in smaller edge coloring and better marginal fit than those of cobalt-chrome copings. Patients are pleased with short-term clinical results.

  14. PREFORMED METAL CROWNS AS A PROSTHETIC RESTORATIONS IN PEDIATRIC DENTISTRY

    Directory of Open Access Journals (Sweden)

    Evgeni Dimitrov

    2017-07-01

    Full Text Available The preformed metal crowns (PMCs are prefabricated constructions, used for restoring a severely broken teeth, affected by multisurfice carious lesions. The aim of the current study is to analyze and criticize the contemporary scientific conclusions related to indications, the usage methods, the advantages and disadvantages of the PMCs, used in the treatment protocol in pediatric dentistry. The subject of the analysis is 64 english language papers, published in the period from 1966 to 2017 y. The analysis shows that disadvantages of these restorations are related to the aesthetics and previous preparation of the hard tooth tissues. The numerous advantages are related to the mechanical durability; the successful tightness concerning the non-operative sealing of caries and the prophylactic effect related to secondary caries lesion as well as the orthodontic jaw malformations, justify the usage of the PMCs in pediatric dentistry and also explain the need of scientific, clinical research in this domain.

  15. Rehabilitation of complicated crown-root fracture by invisible approach

    Directory of Open Access Journals (Sweden)

    V Leela Rani

    2016-01-01

    Full Text Available Dental trauma is one of the most common and significant problems met in all dental offices almost every day. In particular, injury to the anterior teeth is more vulnerable as it may affect the psychosocial behavior, severe emotional complications can occur leading to disturbances in their mental attitude. Cosmetic (lingual orthodontics is the recent development in the field of dentistry in the last few decades. Patients are more concerned about their appearance during the treatment and are affected by psychosocial issues because of labially placed brackets, thus leading to the evolution of lingual orthodontic appliances. In this article, we are sharing our clinical experience treating a complicated crown-root fracture using the lingual orthodontic technique.

  16. Exploring the Use of Suspension in High School Codes of Conduct for Mild, Moderate, and Severe Behaviors

    Science.gov (United States)

    Horwitz, Amy Beth

    2010-01-01

    The purpose of this investigation is to describe the outcomes of a multi-state study of written discipline policies in a high school setting. This study examines discipline codes of conduct and analyzes the content for behaviors ranging in severity (mild, moderate, and severe) while specifically examining the use of suspension as a punitive…

  17. Vegetation response to a short interval between high-severity wildfires in a mixed-evergreen forest

    Science.gov (United States)

    Daniel C. Donato; Joseph B. Fontaine; W. Douglas Robinson; J. Boone Kauffman; Beverly E. Law

    2009-01-01

    Variations in disturbance regime strongly influence ecosystem structure and function. A prominent form of such variation is when multiple high-severity wildfires occur in rapid succession (i.e. short-interval (SI) severe fires, or ‘re-burns’). These events have been proposed as key mechanisms altering successional rates and pathways....

  18. Basal ganglia - thalamus and the crowning enigma

    Directory of Open Access Journals (Sweden)

    Marianela eGarcia-Munoz

    2015-11-01

    Full Text Available When Hubel (1982 referred to layer 1 of primary visual cortex as …a ‘crowning mystery’ to keep area-17 physiologists busy for years to come... he could have been talking about any cortical area. In the 80’s and 90’s there were no methods to examine this neuropile on the surface of the cortex: a tangled web of axons and dendrites from a variety of different places with unknown specificities and doubtful connections to the cortical output neurons some hundreds of microns below. Recently, three changes have made the crowning enigma less of an impossible mission: the clear presence of neurons in layer 1 (L1, the active conduction of voltage along apical dendrites and optogenetic methods that might allow us to look at one source of input at a time. For all of those reasons alone, it seems it is time to take seriously the function of L1. The functional properties of this layer will need to wait for more experiments but already L1 cells are GAD67 positive, i.e., inhibitory! They could reverse the sign of the thalamic glutamate (GLU input for the entire cortex. It is at least possible that in the near future normal activity of individual sources of L1 could be detected using genetic tools. We are at the outset of important times in the exploration of thalamic functions and perhaps the solution to the crowning enigma is within sight. Our review looks forward to that solution from the solid basis of the anatomy of the basal ganglia output to motor thalamus. We will focus on L1, its afferents, intrinsic neurons and its influence on responses of pyramidal neurons in layers 2/3 and 5. Since L1 is present in the whole cortex we will provide a general overview considering evidence mainly from the somatosensory cortex before focusing on motor cortex.

  19. The association between etanercept serum concentration and psoriasis severity is highly age-dependent.

    Science.gov (United States)

    Detrez, Iris; Van Steen, Kristel; Segaert, Siegfried; Gils, Ann

    2017-06-01

    The association between etanercept serum concentration and psoriasis disease severity is poorly investigated, and currently etanercept serum concentration monitoring that is aiming to optimize the psoriasis treatment lacks evidence. In this prospective study, we investigated the relation between etanercept exposure and disease severity via measuring etanercept concentrations at five consecutive time points in 56 psoriasis patients. Disease severity assessments included the Psoriasis Area and Severity Index (PASI), body surface area (BSA) and Physician Global Assessment (PGA), and etanercept and anti-etanercept antibody concentrations were determined every 3 months for a period of 1 year. The present study demonstrated that the association between etanercept concentration and psoriasis severity is age-dependent: when patients were stratified into three groups, patients in the youngest age group (-50 years) showed a lower PASI at a higher etanercept concentration (β = -0.26), whereas patients in the oldest age group (+59 years) showed the opposite trend (β =0.22). Similar age effects were observed in the relation of etanercept concentration with BSA (P=0.02) and PGA (P=0.02). The influence of age and length of time in therapy on the etanercept concentration-disease severity relation was unaffected by body mass index (BMI) or any other possible confounder. Incidence of anti-etanercept antibodies was low (2%). The age-dependent relation between etanercept serum concentrations is both unexpected and intriguing and needs further investigation. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  20. Treatment results of high dose cabergoline as an adjuvant therapy in six patients with established severe ovarian hyper stimulation syndrome.

    Science.gov (United States)

    Saharkhiz, Nasrin; Akbari Sene, Azadeh; Salehpour, Saghar; Tamimi, Maryam; Vasheghani Farahani, Masoumeh; Sheibani, Kourosh

    2014-10-01

    The beneficial role of cabergoline as a prophylactic agent to prevent ovarian hyper stimulation syndrome (OHSS) among high-risk patients has been demonstrated in previous studies. But data for its role as a treatment for established severe OHSS is still limited. We represent the treatment results of high dose oral cabergoline in management of six patients after the syndrome is established. High-dose oral cabergoline (1 mg daily for eight days) was prescribed as an adjuvant to symptomatic treatment for six hospitalized patients with established severe OHSS following infertility treatment cycles. In two cases OHSS resolved rapidly despite the occurrence of ongoing pregnancy. Considering the treatment outcomes of our patients, high dose cabergoline did not eliminate the need for traditional treatments, but it was a relatively effective and safe therapy in management of established severe OHSS, and prevented the increase in its severity following the occurrence of pregnancy.

  1. Hurricane and Severe Storm Sentinel (HS3) Scanning High-Resolution Interferometer Sounder (S-HIS) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) Scanning High-Resolution Interferometer Sounder (S-HIS) measures emitted thermal radiances that are used to obtain...

  2. HURRICANE AND SEVERE STORM SENTINEL (HS3) GLOBAL HAWK HIGH ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) Global Hawk High Altitude MMIC Sounding Radiometer (HAMSR) dataset includes measurements gathered by the HAMSR...

  3. CN-07PREDICTORS OF ACUTE SEVERE LYMPHOPENIA DURING RADIOTHERAPY AND TEMOZOLOMIDE FOR HIGH-GRADE GLIOMA

    Science.gov (United States)

    Huang, Jiayi; Robinson, Clifford; DeWees, Todd; Campian, Jian; Mullen, Daniel; Fergus, Sandra; Kim, Albert; Dunn, Gavin; Tran, David; Simpson, Joseph

    2014-01-01

    BACKGROUND: Acute severe lymphopenia (ASL) frequently develops during radiotherapy and temozolomide (RT + TMZ) for high-grade glioma (HGG) and has been shown to be correlated with survival. This study is designed to identify potential predictors of ASL, especially RT-specific parameters that can be modified. METHODS: From January 2007 to December 2012, 194 patients with HGG were treated RT + TMZ and had available data including lymphocyte count and radiation dose-volume histogram (DVH) parameters. RT was delivered to 2 planning target volumes (PTV1) over a median of 43 days (range 19-75): 60Gy (40.05-66) to PTV 1 and 51Gy (30-54) to PTV2. Concurrent TMZ was given daily at a dose of 75 mg/m2 for the duration of RT. ASL was defined as less than 500/ul (Common Toxicity Criteria version 4.0, grade 3-4) within the first two months from the start of RT. Peripheral blood including lymphocyte count was typically assessed weekly during RT and then monthly thereafter. DVH parameters were determined for brain, brainstem and PTV from the original RT plan. The stepwise logistic regression analysis (SLRA) was used to determine the most important predictors of ASL. RESULTS: Forty-five patients (23%) developed ASL. Patients with ASL had significantly worse OS than those without (median 11.2 vs 18.3 months, respectively, p < 0.001). The SLRA showed that female gender (odd ratio [OR], 5.21; 95% confidence interval [CI], 2.34-11.63), elder age (1.05; 1.01-1.08), higher V25Gy (volume receiving 25Gy) of brain (1.04; 1.01-1.06), lower pretreatment lymphocyte count (1.001; 1.00-1.002) were the most significant predictors for ASL. ASL rate was 40% for patients with V25Gy ≥ 66% and 15% for V25Gy < 66%. CONCLUSIONS: Female gender, elder age, increased V25Gy of brain, and low pretreatment lymphocyte count are significant predictors of ASL during treatment of HGG. Maintaining V25Gy of brain below 66% may reduce the rate of ASL.

  4. Pediatric Preformed Metal Crowns - An Update

    Directory of Open Access Journals (Sweden)

    Sangameshwar Sajjanshetty

    2013-01-01

    Full Text Available Stainless Steel crowns (SSC were introduced in 1947 by the Rocky Mountain Company and popularized by Humphrey in 1950. Prefabricated SSC can be adapted to individual primary teeth and cemented in place to provide a definitive restoration. The SSC is extremely durable, relatively inexpensive, subject to minimal technique sensitivity during placement, and offers the advantage of full coronal coverage. SSC are often used to restore primary and permanent teeth in children and adolescents where intracoronal restorations would otherwise fail. This article brings the update of this definitive restoration.

  5. An Overview of Preformed Metal Crowns. Part 1: Conventional Technique.

    Science.gov (United States)

    Rogers, Helen J; Batley, Haris A; Deery, Chris

    2015-12-01

    This article details the clinical techniques for conventional preformed metal crown placement. It aims to increase the readers' awareness of the clinical advantages of preformed metal crowns and the indications for their use. The second part will discuss the Hall Technique. CPD/Clinical Relevance: This two-part article aims to guide the reader through the conventional and alternative techniques available for placement of a preformed metal crown whilst providing an update of the evidence for each.

  6. Assessment of nickel release from stainless steel crowns.

    OpenAIRE

    Nahid Ramazani; Rahil Ahmadi; Mansure Darijani

    2014-01-01

    Objective: Adverse effects of dental materials, especially metals, have been an important issue in recent decades. Purpose of Study: The purpose of this study was to determine the amount of nickel released from stainless steel crowns in artificial saliva. Materials and Methods: In this in-vitro study, 270 stainless steel crowns were divided into five groups, each with nine subgroups. Each group (I to V) was comprised of four, five, six, seven and eight crowns, respectively. Each subgroup was ...

  7. Metafora Pada Lirik Lagu Soundtrack Anime Guilty Crown

    OpenAIRE

    Marsella, Elin; Isnaini, Zuli Laili; Nimashita, Hana

    2017-01-01

    This study discusses the types of categories and analysis of metaphorical meanings contained in the lyrics of anime anime soundtrack Guilty Crown. The purpose of this study is to determine the type of category and the meaning of the metaphor in the lyrics of anime soundtrack Guilty Crown. The object of this study is four songs of anime soundtrack Guilty Crown. This is a quantitative study with with descriptive method. The result of study found eleven metaphorical expressions and type of categ...

  8. Fatigue resistance of CAD/CAM resin composite molar crowns.

    Science.gov (United States)

    Shembish, Fatma A; Tong, Hui; Kaizer, Marina; Janal, Malvin N; Thompson, Van P; Opdam, Niek J; Zhang, Yu

    2016-04-01

    To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. Fully anatomically shaped monolithic resin composite molar crowns (Lava Ultimate, n=24) and leucite reinforced glass-ceramic crowns (IPS Empress CAD, n=24) were fabricated using CAD/CAM systems. Crowns were cemented on aged dentin-like resin composite tooth replicas (Filtek Z100) with resin-based cements (RelyX Ultimate for Lava Ultimate or Multilink Automix for IPS Empress). Three step-stress profiles (aggressive, moderate and mild) were employed for the accelerated sliding-contact mouth-motion fatigue test. Twenty one crowns from each group were randomly distributed among these three profiles (1:2:4). Failure was designated as chip-off or bulk fracture. Optical and electron microscopes were used to examine the occlusal surface and subsurface damages, as well as the material microstructures. The resin composite crowns showed only minor occlusal damage during mouth-motion step-stress fatigue loading up to 1700N. Cross-sectional views revealed contact-induced cone cracks in all specimens, and flexural radial cracks in 2 crowns. Both cone and radial cracks were relatively small compared to the crown thickness. Extending these cracks to the threshold for catastrophic failure would require much higher indentation loads or more loading cycles. In contrast, all of the glass-ceramic crowns fractured, starting at loads of approximately 450N. Monolithic CAD/CAM resin composite crowns endure, with only superficial damage, fatigue loads 3-4 times higher than those causing catastrophic failure in glass-ceramic CAD crowns. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  9. Reducing fatalities and severe injuries on Florida's high-speed multi-lane arterial corridors : part I, preliminary severity analysis of driver crash involvements, final report, April 2009

    Science.gov (United States)

    2009-04-28

    Severe injury involvements on arterial roads account for a quarter of the total severe injuries reported statewide. Crash severity analysis was conducted and consisted of six road entity models and twenty crash type models. The data preparation and s...

  10. Evaluation of the clinical performance and effectiveness of adhesively-bonded metal crowns on damaged canine teeth of working dogs over a two- to 52-month period.

    Science.gov (United States)

    van Foreest, A; Roeters, J

    1998-03-01

    In this clinical study, 41 metal full crown restorations of canine teeth were placed in 18 working dogs. Twenty-six canine teeth had severe attrition with no involvement of the pulp cavities; 15 fractured canine teeth were endodontically treated. With the exception of one tooth, at least one-third of the coronal part of each canine tooth was available for a supragingivally performed, minimal tooth crown preparation. A dental resin luting cement technique was used to bond the electrolytically etched crown (made from an alloy of cobalt-chrome-molybdenum) to the tooth. The metal crowns were slightly shorter and with a more rounded tip than the original tooth. Posts or post-and-core techniques were not used. Median follow-up period was 30 months (range 2 to 61 months), at which time 36 crowns were found to be intact and functional. Five crowns were lost; three as a result of subsequent injury and fracture of the tooth below the crown; one as a result of use of less than one-third of the coronal portion of the tooth for retention of the crown; and one as a result of an oblique fracture of the root.

  11. Modification of soil nutrients and micro-climate by tree crowns in a ...

    African Journals Online (AJOL)

    Tree crowns in semi-arid areas have often been found to create micro-habitants of improved soil physical and nutrient status and reduced evapotranspiration. These encourage the growth of mesic, palatable and high yielding perennial grasses in otherwise arid environments. A two-year study, in areas with a long history of ...

  12. Metal ion complexation by ionizable crown ethers. Final report, January 1, 1988--June 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, R.A.

    1994-12-31

    During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. The ligands possess one or more ionizable group (carboxylic acid, phosphonic acid monoethyl ester, para-nitrophenol, phosphonic acid) attached to crown ether, monoazacrown ether or diazacrown ether frameworks. These novel chelating agents have either pendent or inward-facing proton-ionizable groups. Such lipophilic proton-ionizable crown ethers are designed for use in multiphase metal ion separations (solvent extraction, liquid membrane transport). In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The influence of structural variations within lipophilic acyclic polyether dicarboxylic acids upon competitive solvent extraction of alkaline earth cations has been probed. Also a new chromogenic, di-ionizable crown ether with extremely high selectivity for Hg{sup 2+} has been discovered.

  13. Can stature be estimated from tooth crown dimensions? A study in a sample of South-East Asians.

    Science.gov (United States)

    Hossain, Mohammad Zakir; Munawar, Khalil M M; Rahim, Zubaidah H A; Bakri, Marina Mohd

    2016-04-01

    Stature estimation is an important step during medico-legal and forensic examination. Difficulty arises when highly decomposed and mutilated dead bodies with fragmentary remains are brought for forensic identification like in mass disaster or airplane crash. The body remains could be just a jaw with some teeth. The objective of this study was to explore if the stature of an individual can be determined from the tooth crown dimensions. A total of 201 volunteers participated in this study. The stature and clinical crown dimensions (length, mesiodistal and labiolingual diameters) of maxillary anterior teeth were measured. Correlation between crown dimensions and stature was analyzed by Pearson correlation test. Regression analysis was used to get equations for estimation of stature from crown measurements. The regression equations were applied in the same sample of volunteers that was used to obtain the equations. The reliability and accuracy of the equations were checked in another sample of volunteers. Length and mesiodistal diameter of the crown of central incisors and canines showed significant albeit low to moderate correlations (0.35-0.45) with the stature. The correlation co-efficient values were higher (as high as 0.537) when summation of the measurements was taken for analysis. The regression equations when applied to the same and a test sample of volunteers revealed that differences between actual and estimated stature can be as low as 0.01 to as much as 16.50cm. The findings suggest that although there are some degrees of positive correlations between stature and tooth crown dimensions, stature estimation from the tooth crown dimensions cannot provide the accuracy of estimation as required in forensic situations. The stature estimation accuracy using tooth crown dimensions is comparable to that of cephalo-facial dimensions but inferior to that of long bones. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Evaluation of calix-crown ionophores for selective separation of radio-cesium from acidic nuclear waste solution

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, P.K. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ansari, S.A. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sarkar, A. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Bhattacharyya, A. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Manchanda, V.K. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)]. E-mail: vkm@magnum.barc.ernet.in

    2006-07-07

    Extraction of Cs-137 from nitric acid was carried out using nitrobenzene solutions of calix-crowns such as calix[4]arene-bis(crown-6) (CC-A), calix[4]arene-bis(benzo crown-6) (CC-B) and calix[4]arene-bis(napthocrown-6) (CC-C). CC-C was found to be superior extractant for Cs(I) as compared to the other two calix-crown ligands used in the present study. The effect of diluent on the extraction of Cs(I) indicated the trend: nitrobenzene > dichloroethane > chloroform > decanol >> carbon tetrachloride {approx} n-hexane {approx} toluene. Subsequently, the studies were carried out with nitrobenzene solutions of the calix-crown ligands (mainly CC-C) on the effects of (a) aqueous phase acidity (b) ligand concentration, and (c) cesium concentration on Cs extraction from nitric acid media. Conditions for quantitative extraction and stripping were optimized and the extracted species conformed to {l_brace}[CsL]{sup +}.[NO{sub 3}]{sup -}.nH{sub 2}O{r_brace}. Selectivity studies were carried out using an irradiated natural U target involving tracer amount of fission products activities. Extraction of Cs(I) from a synthetic high level waste solution was also carried out. The promising results obtained in the present studies indicate possible use of the calix-crown ligand for Cs(I) recovery from the acidic high level waste.

  15. [Comparison of adaptation of crowns of different lithium disilicate glass-ceramic].

    Science.gov (United States)

    Li, Kemeng; Ai, Hongjun; Yi, Zhe

    2016-05-01

    To evaluate the adaptation of different lithium disilicate glass-ceramic crown and whether different fabrication processes affect the adaptation of crowns. Thirty epoxy dies crowns were divided into 3 groups. They were cemented to domestic lithium disilicate glass-ceramic crowns in Group A, to IPS e.max CAD crowns in Group B and to IPS e.max Press crowns in Group C respectively. All crowns were cut by cutting machine. A confocal laser scanning microscope was used to measure the gap between crown tissue surface and die. There were significant differences in the three groups of measurement points(Pglass-ceramic crowns appeared to have clinically acceptable fit.

  16. Severe fatigue after kidney transplantation : a highly prevalent, disabling and multifactorial symptom

    NARCIS (Netherlands)

    Goedendorp, Martine M.; Hoitsma, Andries J.; Bloot, Lotte; Bleijenberg, Gijs; Knoop, Hans

    2013-01-01

    Fatigue is a common symptom of patients with chronic kidney disease, but seldom investigated after transplantation. We determined the prevalence, impact and related factors of severe fatigue in kidney transplant recipients (KTRs). Medical records and questionnaires were used to assess kidney

  17. High-oleic ready-to-use therapeutic food maintains docosahexaenoic acid status in severe malnutrition

    Science.gov (United States)

    Ready-to-use therapeutic food (RUTF) is the preferred treatment for uncomplicated severe acute malnutrition. It contains large amounts of linoleic acid and little a-linolenic acid, which may reduce the availability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to the recovering child...

  18. High C-Reactive Protein Predicts Delirium Incidence, Duration, and Feature Severity After Major Noncardiac Surgery.

    Science.gov (United States)

    Vasunilashorn, Sarinnapha M; Dillon, Simon T; Inouye, Sharon K; Ngo, Long H; Fong, Tamara G; Jones, Richard N; Travison, Thomas G; Schmitt, Eva M; Alsop, David C; Freedman, Steven D; Arnold, Steven E; Metzger, Eran D; Libermann, Towia A; Marcantonio, Edward R

    2017-08-01

    To examine associations between the inflammatory marker C-reactive protein (CRP) measured preoperatively and on postoperative day 2 (POD2) and delirium incidence, duration, and feature severity. Prospective cohort study. Two academic medical centers. Adults aged 70 and older undergoing major noncardiac surgery (N = 560). Plasma CRP was measured using enzyme-linked immunosorbent assay. Delirium was assessed from Confusion Assessment Method (CAM) interviews and chart review. Delirium duration was measured according to number of hospital days with delirium. Delirium feature severity was defined as the sum of CAM-Severity (CAM-S) scores on all postoperative hospital days. Generalized linear models were used to examine independent associations between CRP (preoperatively and POD2 separately) and delirium incidence, duration, and feature severity; prolonged hospital length of stay (LOS, >5 days); and discharge disposition. Postoperative delirium occurred in 24% of participants, 12% had 2 or more delirium days, and the mean ± standard deviation sum CAM-S was 9.3 ± 11.4. After adjusting for age, sex, surgery type, anesthesia route, medical comorbidities, and postoperative infectious complications, participants with preoperative CRP of 3 mg/L or greater had a risk of delirium that was 1.5 times as great (95% confidence interval (CI) = 1.1-2.1) as that of those with CRP less than 3 mg/L, 0.4 more delirium days (P delirium (3.6 CAM-S points higher, P delirium (95% CI = 1.0-2.4) as those in the lowest quartile (≤127.53 mg/L), had 0.2 more delirium days (P delirium (4.5 CAM-S points higher, P delirium incidence, duration, and feature severity. CRP may be useful to identify individuals who are at risk of developing delirium. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

  19. Descriptive statistics of tree crown condition in the North Central United States

    Science.gov (United States)

    KaDonna C. Randolph; Randall S. Morin; Jim Steinman

    2010-01-01

    The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in Illinois, Indiana, Michigan, Minnesota, Missouri, and Wisconsin...

  20. Descriptive statistics of tree crown condition in the United States Interior West

    Science.gov (United States)

    KaDonna C. Randolph; Mike T. Thompson

    2010-01-01

    The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in Colorado, Idaho, Nevada, Utah, and Wyoming between 1996 and...

  1. Descriptive statistics of tree crown condition in California, Oregon, and Washington

    Science.gov (United States)

    KaDonna C. Randolph; Sally J. Campbell; Glenn Christensen

    2010-01-01

    The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four tree crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in California, Oregon, and Washington between 1996 and 1999....

  2. Descriptive statistics of tree crown condition in the Northeastern United States

    Science.gov (United States)

    KaDonna C. Randolph; Randall S. Morin; Jim Steinman

    2010-01-01

    The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in Connecticut, Delaware, Maine, Maryland, Massachusetts, New...

  3. Experimental Research of Mutual Influence of Several Consecutive Water Droplets on Regularities of their Evaporation through High-temperature

    Directory of Open Access Journals (Sweden)

    Antonov Dmitrii V.

    2015-01-01

    Full Text Available Experimental research of the main integral characteristic of several water droplets at their evaporation through high-temperature gases (1100K was carried out. Features of water droplet movement in a high-temperature gas stream are established. Characteristics of droplet movement at a variety of their initial parameters in a wide range was established by high-speed video registration preservers «Phantom» and software packages «Tema Automotive» and «Phantom Camera Control». The main integral characteristics of several water droplets in the different distance between them were installed.

  4. Spectrophotometric analysis of crown discoloration induced by MTA- and ZnOE-based sealers

    Science.gov (United States)

    IOANNIDIS, Konstantinos; MISTAKIDIS, Ilias; BELTES, Panagiotis; KARAGIANNIS, Vassilis

    2013-01-01

    Crown discoloration can be induced by root canal sealer remnants following root canal treatment. Objective: The aim of this study was to evaluate chromatic alterations in human tooth crowns induced by a Mineral Trioxide Aggregate-based sealer (MTA Fillapex® and a commonly used ZnOE-based sealer (Roth-811). The tested null hypothesis was that the application of the materials did not induce clinically perceptible crown discoloration (Ho: CIE color difference ΔEL*a*b* color system and the corresponding ΔE values were calculated. Statistical analysis was performed using two-way mixed ANOVA models, at p=0.05 level of significance. Results: A statistically significant increase in a* and b* chromatic parameters of the MTA Fillapex Group was measured. However, ΔE values did not exceed the human eye perceptibility threshold (set at ΔE<3.7) during the experimental period (ΔEt3=2.88). In Roth-811 Group, a statistically significant decrease in L* and a statistically significant increase in a* and b* chromatic parameters was measured, during all observation periods. Resultant ΔE values exceeded the human eye perceptibility threshold after 1 week (ΔEt1=5.65). Conclusions: Application of MTA Fillapex in tooth crowns resulted in minimal color alterations, while Roth 811 induced severe discoloration, in vitro. It could be suggested that, in terms of aesthetics, the use of MTA Fillapex appears to be favorable. PMID:23739854

  5. Severe Trauma Stress Inoculation Training for Combat Medics using High Fidelity Simulation

    Science.gov (United States)

    2013-12-01

    Interservice/Jndustry Training, Simulation, and Education Conference (/1/ TSEC ) 20/3 responding to lED victims. He has led the development of several...environment. The course is based 13067 Paper No. Page 4 of 12 lnterservicellndustry Training, Simulation, and Education Conference (/1/ TSEC ) 2013 on known...Simulation, and Education Conference (1/! TSEC ) 2013 positive made from it, which a sculptor used to finalize the final casting model. From this positive, a

  6. High dose Erythropoietin increases Brain Tissue Oxygen Tension in Severe Vasospasm after Subarachnoid Hemorrhage

    Directory of Open Access Journals (Sweden)

    Helbok Raimund

    2012-06-01

    Full Text Available Abstract Background Vasospasm-related delayed cerebral ischemia (DCI significantly impacts on outcome after aneurysmal subarachnoid hemorrhage (SAH. Erythropoietin (EPO may reduce the severity of cerebral vasospasm and improve outcome, however, underlying mechanisms are incompletely understood. In this study, the authors aimed to investigate the effect of EPO on cerebral metabolism and brain tissue oxygen tension (PbtO2. Methods Seven consecutive poor grade SAH patients with multimodal neuromonitoring (MM received systemic EPO therapy (30.000 IU per day for 3 consecutive days for severe cerebral vasospasm. Cerebral perfusion pressure (CPP, mean arterial blood pressure (MAP, intracranial pressure (ICP, PbtO2 and brain metabolic changes were analyzed during the next 24 hours after each dose given. Statistical analysis was performed with a mixed effects model. Results A total of 22 interventions were analyzed. Median age was 47 years (32–68 and 86 % were female. Three patients (38 % developed DCI. MAP decreased 2 hours after intervention (P btO2 significantly increased over time (P  Conclusions EPO increases PbtO2 in poor grade SAH patients with severe cerebral vasospasm. The effect on outcome needs further investigation.

  7. Fracture of porcelain-veneered gold-alloy and zirconia molar crowns using a modified test set-up

    Science.gov (United States)

    Larsson, Christel; Drazic, Marko; Nilsson, Eddie; Vult von Steyern, Per

    2015-01-01

    Abstract Objective: The main aim of this study was to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and metal-ceramic (MC) molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP molar crowns veneered with porcelain were manufactured. The crowns were artificially aged before final load to fracture. Load was applied using a 7 mm diameter steel ball exerting force on the cusps with stresses directed toward the core-veneer interface. Fracture surface analysis was performed using light- and scanning electron microscopy. Results: The test design produced fractures of the veneering material rather than complete fractures. MC crowns withstood significantly (p > 0.001) higher loads (mean 2155 N) than Y-TZP (mean 1505 N) crowns, yet both endure loads sufficient for predictable clinical use. Fracture mode differed between MC and Y-TZP. MC crowns exhibited fractures involving the core-veneer interface but without core exposure. One Y-TZP crown suffered a complete fracture, all others except one displayed fractures of the veneering material involving the core-veneer interface with core exposure. Conclusions: The test set-up produces fractures similar to those found in vivo and may be useful to evaluate the core-veneer interface of different material systems, both metals and ceramics. The study confirms suggestions from previous studies of a weaker core-veneer bond for Y-TZP compared to MC crowns. PMID:28642899

  8. Fracture of porcelain-veneered gold-alloy and zirconia molar crowns using a modified test set-up

    Directory of Open Access Journals (Sweden)

    Christel Larsson

    2015-01-01

    Full Text Available Objective: The main aim of this study was to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP and metal-ceramic (MC molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP molar crowns veneered with porcelain were manufactured. The crowns were artificially aged before final load to fracture. Load was applied using a 7 mm diameter steel ball exerting force on the cusps with stresses directed toward the core-veneer interface. Fracture surface analysis was performed using light- and scanning electron microscopy. Results: The test design produced fractures of the veneering material rather than complete fractures. MC crowns withstood significantly (p > 0.001 higher loads (mean 2155 N than Y-TZP (mean 1505 N crowns, yet both endure loads sufficient for predictable clinical use. Fracture mode differed between MC and Y-TZP. MC crowns exhibited fractures involving the core-veneer interface but without core exposure. One Y-TZP crown suffered a complete fracture, all others except one displayed fractures of the veneering material involving the core-veneer interface with core exposure. Conclusions: The test set-up produces fractures similar to those found in vivo and may be useful to evaluate the core-veneer interface of different material systems, both metals and ceramics. The study confirms suggestions from previous studies of a weaker core-veneer bond for Y-TZP compared to MC crowns.

  9. Longevity of metal-ceramic crowns cemented with self-adhesive resin cement: a prospective clinical study

    Science.gov (United States)

    Brondani, Lucas Pradebon; Pereira-Cenci, Tatiana; Wandsher, Vinicius Felipe; Pereira, Gabriel Kalil; Valandro, Luis Felipe; Bergoli, César Dalmolin

    2017-04-10

    Resin cements are often used for single crown cementation due to their physical properties. Self-adhesive resin cements gained widespread due to their simplified technique compared to regular resin cement. However, there is lacking clinical evidence about the long-term behavior of this material. The aim of this prospective clinical trial was to assess the survival rates of metal-ceramic crowns cemented with self-adhesive resin cement up to six years. One hundred and twenty-nine subjects received 152 metal-ceramic crowns. The cementation procedures were standardized and performed by previously trained operators. The crowns were assessed as to primary outcome (debonding) and FDI criteria. Statistical analysis was performed using Kaplan-Meier statistics and descriptive analysis. Three failures occurred (debonding), resulting in a 97.6% survival rate. FDI criteria assessment resulted in scores 1 and 2 (acceptable clinical evaluation) for all surviving crowns. The use of self-adhesive resin cement is a feasible alternative for metal-ceramic crowns cementation, achieving high and adequate survival rates.

  10. Towards highs performance bulk thermoelectric materials with enhanced mechanical properties by Severe Plastic Deformation (SPD)

    OpenAIRE

    Santamaría Regueiro, J.A.(Jon Ander); Gil Sevillano, J. (Javier); Alkorta Barragan, J. (Jon)

    2016-01-01

    Nowadays, one of the most promising strategies to produce highly efficient thermoelectric (TE) materials is to reduce the lattice thermal conductivity by introducing phonon scattering centres (such as submicron sized grain boundaries, second-phase nano-particles, and point defects) at different length scales. For highly anisotropic crystals such as Bi2Te3-based thermoelectrics, the combination of nanosized grain structures (to improve phonon scattering) together with strong crystallographic t...

  11. High Relapse Rates Despite Early Intervention with Intravenous Methylprednisolone Pulse Therapy for Severe Childhood Alopecia Areata.

    Science.gov (United States)

    Smith, Alexandra; Trüeb, Ralph M; Theiler, Martin; Hauser, Valérie; Weibel, Lisa

    2015-01-01

    Previous data suggest that early application of intravenous methylprednisolone pulse therapy (IV-MPPT) may improve the disease course of alopecia areata. The objective of this study was to investigate the outcome of IV-MPPT in severe childhood alopecia areata, predominantly with short disease duration. Eighteen children (10 girls, 8 boys) younger than 17 years old (median age 7.7 yrs, range 2.1-16.5 yrs) treated with IV-MPPT for severe childhood alopecia areata in a referral center for pediatric dermatology over 3 years (median disease duration 4 mos, range 1-12 mos) were retrospectively evaluated. Five patients had alopecia areata totalis or universalis and 13 had alopecia multilocularis. The median scalp area affected by alopecia was 60% (range 30%-100%). All patients underwent two or three cycles of IV-MPPT at monthly intervals (maximum 500 mg/day on three consecutive days). Within 7 months after the last IV-MPPT session, 10 of 18 children had good response (≥75% of hair regrowth), with eight showing improvement within the first 4 months. Of the remaining eight patients, one had moderate response (50%-74% regrowth), three had poor response (1%-49% regrowth), and four (all with alopecia areata universalis or totalis) had no response. Seven of the initial 10 good responders experienced relapses, with marked hair loss after the last IV-MPPT session. The estimated median time to relapse was 8 months (95% confidence interval 7, 9 mos). IV-MPPT, even early in the course of disease, did not affect long-term outcome of alopecia areata in our group of severely affected patients. © 2015 Wiley Periodicals, Inc.

  12. Severe dermatomyositis with pronounced generalized subcutaneous edema and dysphagia: A rare manifestation of a highly active disease

    OpenAIRE

    Peng, Amy Chia-Ying; Huang, Chien-Hun; Lin, Tsy-Sheng; Lee, Julia Yu-Yun

    2014-01-01

    Severe subcutaneous edema is rare in dermatomyositis (DM). Such patients usually have a highly active disease, which requires aggressive treatment. To date, there are 14 reported cases of generalized edema secondary to adult DM. We described a severe case of DM manifesting generalized edema, oropharyngeal dysphagia, and dysarthria. A 44-year-old female presented with a typical rash of DM, proximal muscle weakness, and marked swelling of the limbs and face. The findings in the skin biopsy, mus...

  13. Relationships among alfalfa resistance to Sclerotinia crown and ...

    African Journals Online (AJOL)

    Sclerotinia crown and stem rot (SCSR) of alfalfa caused by Sclerotinia trifoliorum is one of the main constraints for efficient alfalfa cultivation in temperate climate all over the world. The resistance of 200 alfalfa accessions to Sclerotinia crown and stem rot was evaluated during 2010 to 2011 in the field nursery established in ...

  14. Crown ratio models for tropical rainforests species in Oban division ...

    African Journals Online (AJOL)

    Crown ratio (CR) is a characteristic used to describe the crown size, which is an important element of forest growth and yield. It is often used as an important predictor variable for tree-level growth equations. It indicates tree vigour and is an important habitat variable. It is often estimated using allometry. Modified versions of ...

  15. Automatic crown cover mapping to improve forest inventory

    Science.gov (United States)

    Claude Vidal; Jean-Guy Boureau; Nicolas Robert; Nicolas Py; Josiane Zerubia; Xavier Descombes; Guillaume Perrin

    2009-01-01

    To automatically analyze near infrared aerial photographs, the French National Institute for Research in Computer Science and Control developed together with the French National Forest Inventory (NFI) a method for automatic crown cover mapping. This method uses a Reverse Jump Monte Carlo Markov Chain algorithm to locate the crowns and describe those using ellipses or...

  16. Grey Crowned Cranes Balearica regulorum in urban areas of Uganda

    African Journals Online (AJOL)

    landscapes: the case of Crowned Crane breeding and distribution outside Protected Areas in Uganda. African Journal of Ecology 48: 119–125. Pomeroy, d.e. 1980a. Aspects of the ecology of Crowned Crane Balearica regulorum in Uganda. Scopus 4: 29–35. Pomeroy, d.e. 1980b. Growth and plumage changes of the Grey ...

  17. Laser all-ceramic crown removal-a laboratory proof-of-principle study-phase 2 crown debonding time.

    Science.gov (United States)

    Rechmann, Peter; Buu, Natalie C H; Rechmann, Beate M T; Finzen, Frederick C

    2014-10-01

    The removal of all-ceramic crowns is a time consuming procedure in the dental office. Little research has been done in alternative removal techniques for all-ceramic crowns. The objective of the second phase of this proof-of-principle laboratory pilot study was to evaluate whether Ivoclar Vivadent all-ceramic crowns can be efficiently removed from natural teeth without damage to the underlying tooth structure using an Erbium laser. The ceramic materials used were IPS E.max CAD Lithium-disilicate (LS2 ) (E.max CAD) and IPS E.max ZirCAD Zirconium-oxide (ZrO2 ) (ZirCAD) (Ivoclar, Vivadent, Liechtenstein). Molars, either as stand-alone teeth or placed in an artificial row of teeth, were prepared to receive all-ceramic crowns. Copings and full contour crowns with either featheredge or regular margins were produced. The all-ceramic crowns were bonded to the teeth with Ivoclar Multilink Automix. The time for Er:YAG laser debonding of each crown was then measured. The Er:YAG (LiteTouch, Syneron, Yokneam, Israel) was used with an 1,100 µm diameter fiber tip with energies up to 600 mJ per pulse (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µs at 126 mJ/pulse, and 400 µs at 590 mJ/pulse). The irradiation was applied at a distance of 10 mm from the crown surface following a defined pattern. Air-water spray was applied to the crowns at a rate of 67 ml/minute. All of the all-ceramic crowns were successfully debonded with the laser. On average, an all-ceramic E.max CAD crown was debonded in 190 ± 92 seconds (average ± SD). The debonding time for ZirCAD featheredge crowns was 226 ± 105 seconds and for ZirCAD crowns with regular margins it was 312 ± 102 seconds. No crowns fractured and no damage to the underlying dentin was detected. The bonding cement deteriorated due to the Er:YAG irradiation. Additionally, no carbonization at the dentin/cement interface was observed. Er:YAG laser energy can successfully be used

  18. Retention of veneered stainless steel crowns on replicated typodont primary incisors: an in vitro study.

    Science.gov (United States)

    Guelmann, Marcio; Gehring, Daren F; Turner, Clara

    2003-01-01

    The purpose of this in vitro study was to determine the effect of crimping and cementation on retention of veneered stainless steel crowns. One hundred twenty crowns, 90 from 3 commercially available brands of veneered stainless steel crowns (Dura Crown, Kinder Krown, and NuSmile Primary Crown) and 30 (plain) Unitek stainless steel crowns were assessed for retention. An orthodontic wire was soldered perpendicular to the incisal edge of the crowns; the crowns were fitted to acrylic replicas of ideal crown preparations and were divided equally into 3 test groups: group 1--crowns were crimped only (no cement used); group 2--crowns were cemented only; and group 3--crowns were crimped and cemented to the acrylic replicas. An Instron machine recorded the amount of force necessary to dislodge the crowns and the results were statistically analyzed using 2-way ANOVA and Tukey honestly significant difference (HSD) test. Group 3 was statistically more retentive than groups 1 and 2. Group 2 was statistically more retentive than group 1 (P crowns were statistically more retentive than the veneered crowns (P crowns showed statistically less retention values than all other crowns (P crowns showed statistically better retention rates than all other brands (P crowns with veneer facings were significantly more retentive than the nonveneered ones when cement and crimping were combined.

  19. Analysis of severe feather pecking behavior in a high feather pecking selection line

    DEFF Research Database (Denmark)

    Labouriau, R; Kjaer, J B; Abreu, G C G

    2009-01-01

    Even though feather pecking (FP) in laying hens has been extensively studied, a good solution to prevent chickens from this behavior under commercial circumstances has not been found. Selection against FP behavior is possible, but for a more effective selection across different populations......, it is necessary to characterize the genetic mechanism associated with this behavior. In this study, we use a high FP selection line, which has been selected for 8 generations. We present evidence of the presence of a major dominant allele affecting the FP behavior by using an argument based on the presence...... of mixture in the distribution of the observed FP and by studying the evolution of the proportion of very high FP along the sequence of 8 generations. This hypothesis is further supported by the fact that the gene transcription profile of the birds performing high FP differs from the profile of the other...

  20. Effect of the crown design and interface lute parameters on the stress-state of a machined crown-tooth system: a finite element analysis.

    Science.gov (United States)

    Shahrbaf, Shirin; vanNoort, Richard; Mirzakouchaki, Behnam; Ghassemieh, Elaheh; Martin, Nicolas

    2013-08-01

    The effect of preparation design and the physical properties of the interface lute on the restored machined ceramic crown-tooth complex are poorly understood. The aim of this work was to determine, by means of three-dimensional finite element analysis (3D FEA) the effect of the tooth preparation design and the elastic modulus of the cement on the stress state of the cemented machined ceramic crown-tooth complex. The three-dimensional structure of human premolar teeth, restored with adhesively cemented machined ceramic crowns, was digitized with a micro-CT scanner. An accurate, high resolution, digital replica model of a restored tooth was created. Two preparation designs, with different occlusal morphologies, were modeled with cements of 3 different elastic moduli. Interactive medical image processing software (mimics and professional CAD modeling software) was used to create sophisticated digital models that included the supporting structures; periodontal ligament and alveolar bone. The generated models were imported into an FEA software program (hypermesh version 10.0, Altair Engineering Inc.) with all degrees of freedom constrained at the outer surface of the supporting cortical bone of the crown-tooth complex. Five different elastic moduli values were given to the adhesive cement interface 1.8GPa, 4GPa, 8GPa, 18.3GPa and 40GPa; the four lower values are representative of currently used cementing lutes and 40GPa is set as an extreme high value. The stress distribution under simulated applied loads was determined. The preparation design demonstrated an effect on the stress state of the restored tooth system. The cement elastic modulus affected the stress state in the cement and dentin structures but not in the crown, the pulp, the periodontal ligament or the cancellous and cortical bone. The results of this study suggest that both the choice of the preparation design and the cement elastic modulus can affect the stress state within the restored crown

  1. Robustness of Multiple High Speed TCP CUBIC Connections Under Severe Operating Conditions

    DEFF Research Database (Denmark)

    Pilimon, Artur; Ruepp, Sarah Renée; Berger, Michael Stübert

    2015-01-01

    on and supported by packet-level simulations. The results show that the aggressive nature of CUBIC’s nonlinear congestion window control principle causes a degradation of the time-average throughput at the moderate level of random packet loss even under increasing Round-Trip-Time of the flow. However......We study the adaptation capabilities and robustness of the high-speed TCP CUBIC algorithm. For this purpose we consider a network environment with variable and high random packet loss and a large Bandwidth-Delay product, shared by multiple heterogeneous TCP connections. The analysis is based...

  2. Full scale numerical analysis of high performance concrete columns designed to withstand severe blast impact

    DEFF Research Database (Denmark)

    Riisgaard, Benjamin; Georgakis, Christos; Stang, Henrik

    2007-01-01

    Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Particle system, FDSP, combined with a high strength longitudinal flexural rebar arrangement laced together with polymer lacing to avoid shock initiated disintegration of the structural element under blast...... of PETN (85/15) High Explosives at stand off 1600 mm. Additionally, a LS-DYNA material model suitable for predicting the response of Polymer reinforced Compact Reinforced Concrete improved for close-in detonation and a description of the LS-DYNA multi-material Eulerian method for modeling the blast event...

  3. Thoracic Idiopathic Scoliosis Severity Is Highly Correlated with 3D Measures of Thoracic Kyphosis.

    Science.gov (United States)

    Sullivan, T Barrett; Reighard, Fredrick G; Osborn, Emily J; Parvaresh, Kevin C; Newton, Peter O

    2017-06-07

    Loss of thoracic kyphosis has been associated with thoracic idiopathic scoliosis. Modern 3-dimensional (3D) imaging systems allow more accurate characterization of the scoliotic deformity than traditional radiographs. In this study, we utilized 3D calculations to characterize the association between increasing scoliosis severity and changes in the sagittal and axial planes. Patients evaluated in a scoliosis clinic and determined to have either a normal spine or idiopathic scoliosis were included in the analysis. All underwent upright, biplanar radiography with 3D reconstructions. Two-dimensional (2D) measurements of the magnitude of the thoracic major curve and the thoracic kyphosis were recorded. Image processing and MATLAB analysis were utilized to produce a 3D calculation of thoracic kyphosis and apical vertebral axial rotation. Regression analysis was performed to determine the correlation of 2D kyphosis, 3D kyphosis, and apical axial rotation with the magnitude of the thoracic major curve. The 442 patients for whom 2D and 3D data were collected had a main thoracic curve magnitude ranging from 1° to 118°. Linear regression analysis of the 2D and 3D T5-T12 kyphosis versus main thoracic curve magnitude yielded significant models (p scoliosis magnitude increased, at a rate of more than half the increase in the main thoracic curve magnitude. Analysis confirmed a surprisingly strong correlation between scoliosis severity and loss of 3D kyphosis that was absent in the 2D analysis. A similarly strong correlation between curve magnitude and apical axial rotation was evident. These findings lend further credence to the concept that scoliosis progresses in the coronal, sagittal, and axial planes simultaneously. The findings of this study suggest that 3D assessment is critical for adequate characterization of the multiplanar deformity of idiopathic scoliosis and deformity in the sagittal plane is linked to deformity in the coronal plane. Increasing severity of coronal

  4. Separation of americium (III) and strontium (II) using TEHDGA and 18-crown-6

    Energy Technology Data Exchange (ETDEWEB)

    Sinharoy, Prithwish; Khan, Pasupati Nath; Nair, Deepika; Jagasia, Poonam; Dhami, P.S.; Kaushik, C.P.; Banerjee, Kalyan [Bhabha Atomic Research Centre, Mumbai (India). Nuclear Recycle Group; Anitha, M. [Bhabha Atomic Research Centre, Mumbai (India). Rare Earth Development Section; Sharma, J.N. [Bhabha Atomic Research Centre, Mumbai (India). Process Development Div.

    2017-06-01

    This work describes extraction of Am(III) and Sr(II) together with tetra(2-ethylhexyl) diglycolamide (TEHDGA) and selective back-extraction of strontium with a strontium complexant, 18-crown-6, leading to their separation from each other. 0.3 M TEHDGA+5% isodecyl alcohol/n-dodecane was used to extract Am(III) and Sr(II) from 4 M nitric acid into organic phase with very high D (D{sub Am}=1000, D{sub Sr}=22) and 0.1 M 18-crown-6 dissolved in 4 M nitric acid is used for selective stripping of Sr(II) from loaded extract phase. Am(III) left in the extract phase was then stripped with 0.01 M nitric acid. Stripping of Sr(II) was found to increase with increase in 18-crown-6 concentration, at 0.1 M 18-crown-6 dissolved in 4 M nitric acid, 83% of the loaded strontium (D{sub Sr}=0.20) was back-extracted in a single contact while loss of Am(III) was 0.8% (D{sub Am}=122.45). Stoichiometry limit of 1:1 was observed between strontium and 18-crown-6. Strontium was precipitated and separated from the complexant by Na{sub 2}SO{sub 4} or Na{sub 2}CO{sub 3}. This process was tested with simulated solution of high level waste and found suitable for quantitative recovery of strontium with high purity.

  5. Biologic rationale of esthetic crown lengthening using innovative proportion gauges.

    Science.gov (United States)

    Fletcher, Paul

    2011-01-01

    Research shows that practitioners tend to underestimate the amount of tooth structure that must be exposed during a crown lengthening procedure. In the anterior portion of the mouth, this can lead to biologic width problems and subsequent cosmetic issues. This paper presents a biologically based, step-by-step approach to periodontal esthetic crown lengthening. Using a series of innovative measuring gauges, the ideal clinical crown length of a tooth as well as the proper occlusogingival placement of the interproximal papilla will be determined based on established, documented tooth proportion relationships. The biologic crown length of the tooth, defined as the distance from the incisal edge to the bone crest, will subsequently be determined as a function of the clinical crown length, with the ultimate goals being adequate tooth structure for the placement of a restorative margin, establishment of a healthy dentogingival complex, and the placement of an esthetically pleasing definitive restoration.

  6. Focused supervision of high-risk fall dementia patients: a simple method to reduce fall incidence and severity.

    Science.gov (United States)

    Detweiler, Mark B; Kim, Kye Y; Taylor, Brenda Y

    2005-01-01

    Dementia units in nursing homes have a disproportionately high number of demographic risk factors for falls. Many residents have a previous history of falls, the inability to call for assistance, and the inability to remember safety instructions. For interdisciplinary falls review committees, this population may be the most difficult to manage. The Virginia Veterans Care Center (VVCC) Dementia Unit Interdisciplinary Fall Team instituted a novel practice for reducing the number and severity of falls among the highest risk group of dementia patients. Certified nursing assistants (CNAs) were assigned to high-risk residents for focused supervision. The patients received consistent supervision by selected CNAs during the day and evening shifts. Eight residents identified as high risk who continued to have falls despite multiple interventions were selected for the study. A comparison of four months of intervention with the four months prior to the intervention revealed a significant (p = 0. 024) fall reduction during the intervention months. Individually, seven of the eight participants had reduced falls during the intervention period. A 5-point scale for fall severity demonstrated an overall reduction in fall severity during that period. Individually, five of the eight patients had a decreased fall severity, and one had no change. Two patients experienced an increase in fall severity due to ongoing medical problems. While the small number of patients in the study limits the power of the results, this novel intervention of using designated CNAs to supervise high-risk fall residents with dementia may prove helpful for staff in other nursing facilities.

  7. Student-Generated Protective Behaviors to Avert Severe Harm Due to High-Risk Alcohol Consumption

    Science.gov (United States)

    Smith, Sandi W.; LaPlante, Carolyn; Wibert, Wilma Novales; Mayer, Alex; Atkin, Charles K.; Klein, Katherine; Glazer, Edward; Martell, Dennis

    2011-01-01

    High-risk alcohol consumption is a significant problem on college campuses that many students see as a rite of passage in their development into adulthood. Developing effective prevention campaigns designed to lessen or avert the risks associated with alcohol consumption entails understanding how students perceive harmful consequences as well as…

  8. High Diversity of Rabies Viruses Associated with Insectivorous Bats in Argentina: Presence of Several Independent Enzootics

    Science.gov (United States)

    Piñero, Carolina; Gury Dohmen, Federico; Beltran, Fernando; Martinez, Leila; Novaro, Laura; Russo, Susana; Palacios, Gustavo; Cisterna, Daniel M.

    2012-01-01

    Background Rabies is a fatal infection of the central nervous system primarily transmitted by rabid animal bites. Rabies virus (RABV) circulates through two different epidemiological cycles: terrestrial and aerial, where dogs, foxes or skunks and bats, respectively, act as the most relevant reservoirs and/or vectors. It is widely accepted that insectivorous bats are not important vectors of RABV in Argentina despite the great diversity of bat species and the extensive Argentinean territory. Methods We studied the positivity rate of RABV detection in different areas of the country, and the antigenic and genetic diversity of 99 rabies virus (RABV) strains obtained from 14 species of insectivorous bats collected in Argentina between 1991 and 2008. Results Based on the analysis of bats received for RABV analysis by the National Rabies system of surveillance, the positivity rate of RABV in insectivorous bats ranged from 3.1 to 5.4%, depending on the geographic location. The findings were distributed among an extensive area of the Argentinean territory. The 99 strains of insectivorous bat-related sequences were divided into six distinct lineages associated with Tadarida brasiliensis, Myotis spp, Eptesicus spp, Histiotus montanus, Lasiurus blosseviilli and Lasiurus cinereus. Comparison with RABV sequences obtained from insectivorous bats of the Americas revealed co-circulation of similar genetic variants in several countries. Finally, inter-species transmission, mostly related with Lasiurus species, was demonstrated in 11.8% of the samples. Conclusions This study demonstrates the presence of several independent enzootics of rabies in insectivorous bats of Argentina. This information is relevant to identify potential areas at risk for human and animal infection. PMID:22590657

  9. High diversity of rabies viruses associated with insectivorous bats in Argentina: presence of several independent enzootics.

    Directory of Open Access Journals (Sweden)

    Carolina Piñero

    Full Text Available BACKGROUND: Rabies is a fatal infection of the central nervous system primarily transmitted by rabid animal bites. Rabies virus (RABV circulates through two different epidemiological cycles: terrestrial and aerial, where dogs, foxes or skunks and bats, respectively, act as the most relevant reservoirs and/or vectors. It is widely accepted that insectivorous bats are not important vectors of RABV in Argentina despite the great diversity of bat species and the extensive Argentinean territory. METHODS: We studied the positivity rate of RABV detection in different areas of the country, and the antigenic and genetic diversity of 99 rabies virus (RABV strains obtained from 14 species of insectivorous bats collected in Argentina between 1991 and 2008. RESULTS: Based on the analysis of bats received for RABV analysis by the National Rabies system of surveillance, the positivity rate of RABV in insectivorous bats ranged from 3.1 to 5.4%, depending on the geographic location. The findings were distributed among an extensive area of the Argentinean territory. The 99 strains of insectivorous bat-related sequences were divided into six distinct lineages associated with Tadarida brasiliensis, Myotis spp, Eptesicus spp, Histiotus montanus, Lasiurus blosseviilli and Lasiurus cinereus. Comparison with RABV sequences obtained from insectivorous bats of the Americas revealed co-circulation of similar genetic variants in several countries. Finally, inter-species transmission, mostly related with Lasiurus species, was demonstrated in 11.8% of the samples. CONCLUSIONS: This study demonstrates the presence of several independent enzootics of rabies in insectivorous bats of Argentina. This information is relevant to identify potential areas at risk for human and animal infection.

  10. Yersinia pestis intracellular parasitism of macrophages from hosts exhibiting high and low severity of plague.

    Directory of Open Access Journals (Sweden)

    Duraisamy Ponnusamy

    Full Text Available BACKGROUND: Yersinia pestis causes severe disease in natural rodent hosts, but mild to inapparent disease in certain rodent predators such as dogs. Y. pestis initiates infection in susceptible hosts by parasitizing and multiplying intracellularly in local macrophages prior to systemic dissemination. Thus, we hypothesize that Y. pestis disease severity may depend on the degree to which intracellular Y. pestis overcomes the initial host macrophage imposed stress. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis, the progression of in vitro infection by Y. pestis KIM62053.1+ of mouse splenic and RAW264.7 tissue culture macrophages and dog peripheral blood-derived and DH82 tissue culture macrophages was studied using microscopy and various parameters of infection. The study showed that during the early stage of infection, intracellular Y. pestis assumed filamentous cellular morphology with multiple copies of the genome per bacterium in both mouse and dog macrophages. Later, in mouse macrophages, the infection elicited spacious vacuolar extension of Yersinia containing vacuoles (YCV, and the filamentous Y. pestis reverted to coccobacillary morphology with genomic equivalents approximately equaling colony forming units. In contrast, Y. pestis infected dog macrophages did not show noticeable extension of YCV, and intracellular Y. pestis retained the filamentous cellular morphology for the entire experiment in DH82 cells or were killed by blood-derived macrophages. In addition, during the later stage of infection, Y. pestis infected mouse macrophages exhibited cell lysis whereas dog macrophages did not. CONCLUSION/SIGNIFICANCE: Overall, these results support our hypothesis that Y. pestis in mouse macrophages can overcome the initial intracellular stress necessary for subsequent systemic infection. However, in dogs, failure of Y. pestis to overcome macrophage imposed stress may result in mild or in apparent disease in dogs.

  11. Long-term results after Ilizarov treatment for severe high-energy injuries of the elbow.

    Science.gov (United States)

    Fodor, Lucian; Ullmann, Yehuda; Soudry, Michael; Lerner, Alexander

    2009-06-01

    Clinical aspects, such as the long-term results after circular external fixation and functional rehabilitation after high-energy injuries of the elbow joint, have not received sufficient attention in the literature. Fourteen patients with high-energy elbow injuries were treated in our hospital over the last 15 years with a circular external fixation frame. The mechanism of injury was blast in eight patients, gunshot wounds in two, motor vehicle crash in two, and fall from height in two. Twelve patients had high-energy open periarticular fractures, nine had Gustillo-Anderson 3B fractures, and three had Gustillo-Anderson 3C fractures. Two patients suffered from closed high-energy periarticular elbow injuries. Seven patients had associated peripheral neurologic injuries and three had vascular injuries. Average Ilizarov fixation time was 20 weeks (range, 6-47 weeks). The follow-up period varied from 1.5 years to 11 years. The average arc of elbow flexion was 110.4 degrees and extension was 19.6 degrees. The average arc of forearm rotation was of 63.5 degrees for pronation (range, 5-90 degrees) and 63.2 degrees for supination (range, 5-90 degrees). The average Mayo Elbow Performance Index score was 84 points (range, 60-100) and the average Khalfayan functional score was 83.4 (range, 68.7-100). Long-term follow-up proved that the hinged Ilizarov/hybrid frame represents a useful instrument to provide stabilization of the elbow joint while facilitating early movements and physiotherapy. The main indication is patients who suffered from open high-energy contaminated fractures with extensive soft-tissue damage (e.g., blast, war injuries) and combined bone and ligaments injuries.

  12. Multiseasonal Tree Crown Structure Mapping with Point Clouds from OTS Quadrocopter Systems

    Science.gov (United States)

    Hese, S.; Behrendt, F.

    2017-08-01

    OTF (Off The Shelf) quadro copter systems provide a cost effective (below 2000 Euro), flexible and mobile platform for high resolution point cloud mapping. Various studies showed the full potential of these small and flexible platforms. Especially in very tight and complex 3D environments the automatic obstacle avoidance, low copter weight, long flight times and precise maneuvering are important advantages of these small OTS systems in comparison with larger octocopter systems. This study examines the potential of the DJI Phantom 4 pro series and the Phantom 3A series for within-stand and forest tree crown 3D point cloud mapping using both within stand oblique imaging in different altitude levels and data captured from a nadir perspective. On a test site in Brandenburg/Germany a beach crown was selected and measured with 3 different altitude levels in Point Of Interest (POI) mode with oblique data capturing and deriving one nadir mosaic created with 85/85 % overlap using Drone Deploy automatic mapping software. Three different flight campaigns were performed, one in September 2016 (leaf-on), one in March 2017 (leaf-off) and one in May 2017 (leaf-on) to derive point clouds from different crown structure and phenological situations - covering the leaf-on and leafoff status of the tree crown. After height correction, the point clouds where used with GPS geo referencing to calculate voxel based densities on 50 × 10 × 10 cm voxel definitions using a topological network of chessboard image objects in 0,5 m height steps in an object based image processing environment. Comparison between leaf-off and leaf-on status was done on volume pixel definitions comparing the attributed point densities per volume and plotting the resulting values as a function of distance to the crown center. In the leaf-off status SFM (structure from motion) algorithms clearly identified the central stem and also secondary branch systems. While the penetration into the crown

  13. MULTISEASONAL TREE CROWN STRUCTURE MAPPING WITH POINT CLOUDS FROM OTS QUADROCOPTER SYSTEMS

    Directory of Open Access Journals (Sweden)

    S. Hese

    2017-08-01

    Full Text Available OTF (Off The Shelf quadro copter systems provide a cost effective (below 2000 Euro, flexible and mobile platform for high resolution point cloud mapping. Various studies showed the full potential of these small and flexible platforms. Especially in very tight and complex 3D environments the automatic obstacle avoidance, low copter weight, long flight times and precise maneuvering are important advantages of these small OTS systems in comparison with larger octocopter systems. This study examines the potential of the DJI Phantom 4 pro series and the Phantom 3A series for within-stand and forest tree crown 3D point cloud mapping using both within stand oblique imaging in different altitude levels and data captured from a nadir perspective. On a test site in Brandenburg/Germany a beach crown was selected and measured with 3 different altitude levels in Point Of Interest (POI mode with oblique data capturing and deriving one nadir mosaic created with 85/85 % overlap using Drone Deploy automatic mapping software. Three different flight campaigns were performed, one in September 2016 (leaf-on, one in March 2017 (leaf-off and one in May 2017 (leaf-on to derive point clouds from different crown structure and phenological situations – covering the leaf-on and leafoff status of the tree crown. After height correction, the point clouds where used with GPS geo referencing to calculate voxel based densities on 50 × 10 × 10 cm voxel definitions using a topological network of chessboard image objects in 0,5 m height steps in an object based image processing environment. Comparison between leaf-off and leaf-on status was done on volume pixel definitions comparing the attributed point densities per volume and plotting the resulting values as a function of distance to the crown center. In the leaf-off status SFM (structure from motion algorithms clearly identified the central stem and also secondary branch systems. While the penetration into the

  14. Effects of Added Salts on Surface Tension and Aggregation of Crown Ether Surfactants.

    Science.gov (United States)

    Suzuki, Maki; Fujio, Katsuhiko

    2016-01-01

    Two crown ether surfactants, dodecanoyloxymethyl- (C11Φ6) and octanoyloxymethyl-18-crown-6 (C7Φ6), were synthesized and the surface tension dependence on surfactant concentration of their aqueous solutions was measured both in the absence and presence of alkali chlorides to confirm the critical micelle concentration (CMC) is highest for the added cation that have an ionic diameter comparable to the hole size of the crown ether ring and that several break points on the surface tension vs. concentration curves occur for these crown ether surfactants. For C11Φ6 and C7Φ6, in the absence of salt, the surface tension vs. concentration curves had two break points. Using the solubilization of a water-insoluble dye as an indicator, we found that the break point at the higher concentration (m0) for C7Φ6 was due to micelle formation. Two break points were also observed for the aqueous solution of C11Φ6 in the presence of NaCl, KCl, RbCl, and CsCl salts at concentrations of 0.22 mol kg(-1) and for C7Φ6 with 0.22 mol kg(-1) KCl added. The CMC (m0) was found to be the highest for solutions containing K(+) salts because K(+) has an ionic diameter comparable to the hole size of 18-crown-6 ring. Furthermore, the CMC decreased as the ionic diameters of the added cations deviated from the hole size. The molecular areas at two break points, estimated by the Gibbs adsorption isotherm, except for that at the break point at mI of C7Φ6, were very small for an adsorbed monolayer. Further investigation is required to elucidate the reason for the break point at mI.

  15. Severe aortic valve stenosis in the elderly: high prevalence of sleep-related breathing disorders

    Directory of Open Access Journals (Sweden)

    Keymel S

    2015-09-01

    Full Text Available Stefanie Keymel,1 Katharina Hellhammer,1 Tobias Zeus,1 Marc Merx,2 Malte Kelm,1 Stephan Steiner3 1Department of Cardiology, Pneumology, and Vascular Diseases, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, 2Department of Cardiology, Vascular Diseases and Intensive Care Medicine, KRHKlinikum Robert Koch Gehrden, Gehrden, 3Department of Cardiology, Pneumology and Intensive Care Medicine, St Vincenz Hospital, Limburg, Germany Background: Aortic valve stenosis is common in the elderly, with a prevalence of nearly 3% in patients aged 75 years or older. Despite the fact that sleep-related breathing disorders (SRBD are thought to be associated with cardiac disease, little is known about their prevalence in this patient cohort. The purpose of this study was to evaluate the prevalence of SRBD in older patients with aortic valve stenosis admitted for transcatheter aortic valve implantation.Methods: Forty-eight consecutive patients (mean age 81±6 years; 37.5% male with symptomatic aortic valve stenosis and considered for transcatheter aortic valve replacement were screened for SRBD. Sleep studies were performed by in-hospital unattended cardiorespiratory polygraphy measuring nasal air flow, chest and abdominal efforts, as well as oxygen saturation and body position. The patients were divided in subgroups dependent on the documented apnea–hypopnea index (AHI; no SRBD was defined as an AHI of <5 events/hour; mild SRBD as AHI 5–15 events/hour, and moderate to severe SRBD as AHI ≥15 events/hour.Results: Thirty-seven patients (77% had SRBD defined as an AHI of ≥5 events/hour. Eleven patients had an unremarkable investigation, with AHI <5 events/hour (mean 3.0±1.3 events/hour. Among patients with sleep apnea, 19 patients had mild SRBD, with an AHI of 5–15 events/hour (mean 9.9±3.4 events/hour and 18 patients had moderate to severe SRBD (mean 26.6±11.3 events/hour. Mainly, obstructive apneas were found. Subgroups were not

  16. Retention of gold alloy crowns cemented with traditional and resin cements.

    Science.gov (United States)

    Pinzón, Lilliam M; Frey, Gary N; Winkler, Mark M; Tate, William H; Burgess, John O; Powers, John M

    2009-01-01

    The aim of this study was to measure in vitro retention of cast gold crowns cemented with traditional and resin cements. Forty-eight human molars were prepared on a lathe to produce complete crown preparations with a consistent taper and split into six groups, eight crowns in each group. Crowns were cast in a high-gold alloy and then cemented. After 24 hours, the retention force (N) was recorded and mean values were analyzed by one-way analysis of variance and the Fisher post-hoc least significant difference (PLSD) multiple comparisons test (a = .05). Failure sites were examined under 3100 magnification and recorded. Mean values (SD) for each group in increasing order of retention force were: Harvard Cement: 43 N (27), TempoCem: 59 N (16), PermaCem Dual: 130 N (42), RelyX Luting Cement: 279 N (26), Contax and PermaCem Dual: 286 N (38), and TempoCem with Contax and PermaCem Dual: 340 N (14). The Fisher PLSD interval (P = .05) for comparing cements was 29 N. Zinc-phosphate cement and provisional resin cements had the lowest retention forces. Resin cement with a bonding agent and the hybrid-ionomer cement had similar retention forces. Resin cement with a bonding agent applied after use of a provisional resin cement had a significantly higher retention force than the other cements tested.

  17. Fracture Strength of Zirconia and Alumina Ceramic Crowns Supported by Implants.

    Science.gov (United States)

    Traini, Tonino; Sorrentino, Roberto; Gherlone, Enrico; Perfetti, Federico; Bollero, Patrizio; Zarone, Ferdinando

    2015-07-01

    Due to the brittleness and limited tensile strength of the veneering glass-ceramic materials, the methods that combine strong core material (as zirconia or alumina) are still under debate. The present study aims to evaluate the fracture strength and the mechanism of failure through fractographic analysis of single all-ceramic crowns supported by implants. Forty premolar cores were fabricated with CAD/CAM technology using alumina (n = 20) and zirconia (n = 20). The specimens were veneered with glass-ceramic, cemented on titanium abutments, and subjected to loading test until fracture. SEM fractographic analysis was also performed. The fracture load was 1165 (±509) N for alumina and 1638 (±662) N for zirconia with a statistically significant difference between the two groups (P = 0.026). Fractographic analysis of alumina-glass-ceramic crowns, showed the presence of catastrophic cracks through the entire thickness of the alumina core; for the zirconia-glass-ceramic crowns, the cracks involved mainly the thickness of the ceramic veneering layer. The sandblast procedure of the zirconia core influenced crack path deflection. Few samples (n = 3) showed limited microcracks of the zirconia core. Zirconia showed a significantly higher fracture strength value in implant-supported restorations, indicating the role played by the high resistant cores for premolar crowns.

  18. Reliability of reduced-thickness and thinly veneered lithium disilicate crowns.

    Science.gov (United States)

    Silva, N R F A; Bonfante, E A; Martins, L M; Valverde, G B; Thompson, V P; Ferencz, J L; Coelho, P G

    2012-03-01

    The present investigation hypothesized that the reliability of reduced-thickness monolithic lithium disilicate crowns is high relative to that of veneered zirconia (Y-TZP) and comparable with that of metal ceramic (MCR) systems. CAD/CAM first mandibular molar full-crown preparations were produced with uniform thicknesses of either 1.0-mm or 2.0-mm occlusal and axial reduction, then replicated in composite for standard crown dies. Monolithic 1.0-mm (MON) and 2.0-mm CAD/CAM lithium disilicate crowns, the latter with a buccal thin veneer (BTV) of 0.5 mm, were fabricated and then sliding-contact-fatigued (step-stress method) until failure or suspension (n = 18/group). Crack evolution was followed, and fractography of post mortem specimens was performed and compared with that of clinical specimens. Use level probability Weibull calculation (use load = 1,200 N) showed interval overlaps between MON and BTV. There was no significant difference between the Weibull characteristic failure loads of MON and BTV (1,535 N [90% CI 1,354-1,740] and 1,609 N [90% CI 1,512-1,712], respectively), which were significantly higher than that of Y-TZP (370 N [90% CI 322-427]) and comparable with that of MCR (1,304 N [90% CI 1,203-1,414]), validating the study hypothesis.

  19. Reliability of Reduced-thickness and Thinly Veneered Lithium Disilicate Crowns

    Science.gov (United States)

    Silva, N.R.F.A.; Bonfante, E.A.; Martins, L.M.; Valverde, G.B.; Thompson, V.P.; Ferencz, J.L.; Coelho, P.G.

    2012-01-01

    The present investigation hypothesized that the reliability of reduced-thickness monolithic lithium disilicate crowns is high relative to that of veneered zirconia (Y-TZP) and comparable with that of metal ceramic (MCR) systems. CAD/CAM first mandibular molar full-crown preparations were produced with uniform thicknesses of either 1.0-mm or 2.0-mm occlusal and axial reduction, then replicated in composite for standard crown dies. Monolithic 1.0-mm (MON) and 2.0-mm CAD/CAM lithium disilicate crowns, the latter with a buccal thin veneer (BTV) of 0.5 mm, were fabricated and then sliding-contact-fatigued (step-stress method) until failure or suspension (n = 18/group). Crack evolution was followed, and fractography of post mortem specimens was performed and compared with that of clinical specimens. Use level probability Weibull calculation (use load = 1,200 N) showed interval overlaps between MON and BTV. There was no significant difference between the Weibull characteristic failure loads of MON and BTV (1,535 N [90% CI 1,354–1,740] and 1,609 N [90% CI 1,512–1,712], respectively), which were significantly higher than that of Y-TZP (370 N [90% CI 322–427]) and comparable with that of MCR (1,304 N [90% CI 1,203–1,414]), validating the study hypothesis. PMID:22205635

  20. Optoelectronics of inverted type-I CdS/CdSe core/crown quantum ring

    Science.gov (United States)

    Bose, Sumanta; Fan, Weijun; Zhang, Dao Hua

    2017-10-01

    Inverted type-I heterostructure core/crown quantum rings (QRs) are quantum-efficient luminophores, whose spectral characteristics are highly tunable. Here, we study the optoelectronic properties of type-I core/crown CdS/CdSe QRs in the zincblende phase—over contrasting lateral size and crown width. For this, we inspect their strain profiles, transition energies, transition matrix elements, spatial charge densities, electronic bandstructures, band-mixing probabilities, optical gain spectra, maximum optical gains, and differential optical gains. Our framework uses an effective-mass envelope function theory based on the 8-band k ṡ p method employing the valence force field model for calculating the atomic strain distributions. The gain calculations are based on the density-matrix equation and take into consideration the excitonic effects with intraband scattering. Variations in the QR lateral size and relative widths of core and crown (ergo the composition) affect their energy levels, band-mixing probabilities, optical transition matrix elements, emission wavelengths/intensities, etc. The optical gain of QRs is also strongly dimension and composition dependent with further dependency on the injection carrier density causing the band-filling effect. They also affect the maximum and differential gain at varying dimensions and compositions.

  1. Identification of several high-risk HPV inhibitors and drug targets with a novel high-throughput screening assay

    Science.gov (United States)

    Toots, Mart; Ustav, Mart; Männik, Andres; Mumm, Karl; Tämm, Kaido; Tamm, Tarmo; Ustav, Mart

    2017-01-01

    Human papillomaviruses (HPVs) are oncogenic viruses that cause numerous different cancers as well as benign lesions in the epithelia. To date, there is no effective cure for an ongoing HPV infection. Here, we describe the generation process of a platform for the development of anti-HPV drugs. This system consists of engineered full-length HPV genomes that express reporter genes for evaluation of the viral copy number in all three HPV replication stages. We demonstrate the usefulness of this system by conducting high-throughput screens to identify novel high-risk HPV-specific inhibitors. At least five of the inhibitors block the function of Tdp1 and PARP1, which have been identified as essential cellular proteins for HPV replication and promising candidates for the development of antivirals against HPV and possibly against HPV-related cancers. PMID:28182794

  2. High-precision timeline for Earth’s most severe extinction

    Science.gov (United States)

    Burgess, Seth D.; Bowring, Samuel; Shen, Shu-zhong

    2014-01-01

    The end-Permian mass extinction was the most severe loss of marine and terrestrial biota in the last 542 My. Understanding its cause and the controls on extinction/recovery dynamics depends on an accurate and precise age model. U-Pb zircon dates for five volcanic ash beds from the Global Stratotype Section and Point for the Permian-Triassic boundary at Meishan, China, define an age model for the extinction and allow exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Mya, an interval of 60 ± 48 ka. Onset of a major reorganization of the carbon cycle immediately precedes the initiation of extinction and is punctuated by a sharp (3‰), short-lived negative spike in the isotopic composition of carbonate carbon. Carbon cycle volatility persists for ∼500 ka before a return to near preextinction values. Decamillenial to millennial level resolution of the mass extinction and its aftermath will permit a refined evaluation of the relative roles of rate-dependent processes contributing to the extinction, allowing insight into postextinction ecosystem expansion, and establish an accurate time point for evaluating the plausibility of trigger and kill mechanisms. PMID:24516148

  3. Microstructure characterization of high-purity aluminum processed by dynamic severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Dirras, Guy; Chauveau, Thierry; Ramtani, Salah; Bui, Quang-Hien [LPMTM, CNRS, UPR 9001, Universite Paris 13, 99 avenue J. B. Clement, 93430 Villetaneuse (France); Abdul-Latif, Akrum [Laboratoire d' Ingenierie des Systemes Mecaniques et des Materiaux, 3 rue Fernand Hainaut, 93407 St Ouen Cedex (France)

    2010-10-15

    Fine-grained aluminum (700-1000 nm) was processed by dynamic severe plastic deformation of coarse-grained (3 mm) pure aluminum (99.999 wt.%). The resulting microstructure was characterized by transmission electron microscopy (TEM) and X-ray profile analyses. It is observed that the grain size determined by TEM departs from measurements made by X-ray profile analysis. In the latter case, the average crystallite size determined over the global crystallographic or on the deformation-induced texture components, namely {l_brace}123{r_brace} left angle 751 right angle, {l_brace}100{r_brace} left angle 011 right angle, and {l_brace}223{r_brace} left angle 154 right angle, yields similar values ({proportional_to}225 nm). By contrast, the dislocation density determined on these texture components is about two times higher than the one measured on the global texture. The difference might be related to the specificities of the induced crystallographic texture. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. Severe Eosinophilic Syndrome: Highly Unlikely Associated with the Use of Probiotic Supplements!

    Directory of Open Access Journals (Sweden)

    Arthur C. Ouwehand

    2013-01-01

    Full Text Available A recent report in this journal suggested a causal relation between probiotic consumption and eosinophilia. In our opinion, the data presented does not suggest such a relationship. The two described eosinophilia cases have not been shown to be caused by infection and certainly not by probiotic infection. The consumed probiotics could not be retrieved in shops, so their identity remains unknown. Furthermore, the alleged consumption took place 2–4 weeks prior to the onset of the symptoms; during such time period, probiotics tend to have disappeared from the intestine. Because most probiotic health benefits are strain specific, also potential risks are strain specific. Thus, generalizing a risk to probiotics as a class is incorrect. We do, however, agree with the authors of the case report that quality control of probiotics should be rigorous. We also do not dispute that there may be certain risk groups (e.g. severely immune-compromised patients, where probiotic use should be carefully monitored. In conclusion, the data presented in the case report do not indicate that specific probiotics strains might cause eosinophilia.

  5. Severe influenza-associated respiratory infection in high HIV prevalence setting, South Africa, 2009-2011.

    Science.gov (United States)

    Cohen, Cheryl; Moyes, Jocelyn; Tempia, Stefano; Groom, Michelle; Walaza, Sibongile; Pretorius, Marthi; Dawood, Halima; Chhagan, Meera; Haffejee, Summaya; Variava, Ebrahim; Kahn, Kathleen; Tshangela, Akhona; von Gottberg, Anne; Wolter, Nicole; Cohen, Adam L; Kgokong, Babatyi; Venter, Marietjie; Madhi, Shabir A

    2013-11-01

    Data on influenza epidemiology in HIV-infected persons are limited, particularly for sub-Saharan Africa, where HIV infection is widespread. We tested respiratory and blood samples from patients with acute lower respiratory tract infections hospitalized in South Africa during 2009-2011 for viral and pneumococcal infections. Influenza was identified in 9% (1,056/11,925) of patients enrolled; among influenza case-patients, 358 (44%) of the 819 who were tested were infected with HIV. Influenza-associated acute lower respiratory tract infection incidence was 4-8 times greater for HIV-infected (186-228/100,000) than for HIV-uninfected persons (26-54/100,000). Furthermore, multivariable analysis showed HIV-infected patients were more likely to have pneumococcal co-infection; to be infected with influenza type B compared with type A; to be hospitalized for 2-7 days or >7 days; and to die from their illness. These findings indicate that HIV-infected persons are at greater risk for severe illnesses related to influenza and thus should be prioritized for influenza vaccination.

  6. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent.

    Science.gov (United States)

    Awual, Md Rabiul; Yaita, Tsuyoshi; Taguchi, Tomitsugu; Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro

    2014-08-15

    Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs-π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Switchable Diastereoselectivity in the Fluoride Promoted Vinylogous Mukaiyama-Michael Reaction of 2-Trimethylsilyloxyfuran Catalyzed by Crown Ethers

    KAUST Repository

    Della Sala, Giorgio

    2017-05-31

    The fluoride promoted vinylogous Mukaiyama-Michael reaction (VMMR) of 2-trimethylsilyloxyfuran with diverse α,β-unsaturated ketones is described. The TBAF catalyzed VMMR afforded high anti-diastereoselectivity irrespective of the solvents used. The KF/crown ethers catalytic systems proved to be highly efficient in terms of yields and resulted in a highly diastereoselective unprecedented solvent/catalyst switchable reaction. Anti-adducts were obtained as single diastereomers or with excellent diastereoselectivities when benzo-15-crown-5 in CH2Cl2 was employed. On the other hand, high syn-diastereoselectivities (from 76:24 to 96:4) were achieved by employing dicyclohexane-18-crown-6 in toluene. Based on DFT calculations, the catalysts/solvents-dependent switchable diastereoselectivities are proposed to be the result of loose or tight cation-dienolate ion pairs.

  8. Effect of Resin Cement Mixing Method on the Retention Strength of a CAD/CAM Zirconia Crowns.

    Science.gov (United States)

    Sadighpour, Leyla; Fazel, Akbar; Geramipanah, Farideh; Allahdadi, Mahdi

    2014-12-01

    Several treatments have been suggested to improve the retention of zirconia-based restorations luted with different cements. Resin cements are believed to improve crown retention under certain circumstances. The aim of the present study was to examine the effect of three cements with different mixing methods on the retention of CAD/CAM zirconia crowns. Thirty extracted human molars were randomly divided into three groups and prepared for all-ceramic crowns (6° taper, 4-mm height and a 1.2 mm rounded shoulder finish line). A zirconia crown (Tizian CAD/CAM) was fabricated for each tooth. The crowns were air-abraded using airborne particles, adjusted, and cemented to the corresponding tooth with one of the following cements: Panavia F2 (PAN group), RelyX Unicem (UNH group) or RelyX Unicem Aplicap (UNA group). After 3,000 rounds of thermal cycling, retention was measured using a specific retentive jig and a universal testing machine. The retention strength was measured by dividing the retention force by the surface area of each tooth. The means of the pull-out test results for each group were compared using analysis of variance and Tukey's HSD test (α = 0.05). The mode of failure was examined using a stereomicroscope. The mean retention value was 6.45 (0.34) MPa for the UNA group, 4.99 MPa (0.47) for the UNH group, and 4.45 (0.39) for the PAN group; the differences among the three test groups were significant. A mixed failure was observed in 83.3 % of specimens, while no cohesive failure occurred in the crowns. Within the limitations of the present study, of the three tested cements, Relyx Unicem Aplicap cement was associated with the highest retention force for Tizian zirconia crowns.

  9. The relationship between alexithymia, anxiety, depression, and internet addiction severity in a sample of Italian high school students.

    Science.gov (United States)

    Scimeca, Giuseppe; Bruno, Antonio; Cava, Lucia; Pandolfo, Gianluca; Muscatello, Maria Rosaria Anna; Zoccali, Rocco

    2014-01-01

    We aimed to assess whether Internet addiction (IA) severity was related to alexithymia scores among high school students, taking into account the role of gender differences and the possible effect of anxiety, depression, and age. Participants in the study were 600 students (ages ranging from 13 to 22; 48.16% girls) recruited from three high schools in two cities from Southern Italy. Participants completed a sociodemographic questionnaire, the Toronto Alexithymia Scale, the Internet Addiction Test, the Hamilton Anxiety Scale, and the Hamilton Depression Scale. The findings of the study showed that IA scores were associated with alexithymia scores, over and above the effect of negative emotions and age. Students with pathological levels of alexithymia reported higher scores on IA severity. In particular, results showed that difficulty in identifying feelings was significantly associated with higher scores on IA severity. No effect of gender was found. Implications for clinicians were discussed.

  10. The Relationship between Alexithymia, Anxiety, Depression, and Internet Addiction Severity in a Sample of Italian High School Students

    Directory of Open Access Journals (Sweden)

    Giuseppe Scimeca

    2014-01-01

    Full Text Available We aimed to assess whether Internet addiction (IA severity was related to alexithymia scores among high school students, taking into account the role of gender differences and the possible effect of anxiety, depression, and age. Participants in the study were 600 students (ages ranging from 13 to 22; 48.16% girls recruited from three high schools in two cities from Southern Italy. Participants completed a sociodemographic questionnaire, the Toronto Alexithymia Scale, the Internet Addiction Test, the Hamilton Anxiety Scale, and the Hamilton Depression Scale. The findings of the study showed that IA scores were associated with alexithymia scores, over and above the effect of negative emotions and age. Students with pathological levels of alexithymia reported higher scores on IA severity. In particular, results showed that difficulty in identifying feelings was significantly associated with higher scores on IA severity. No effect of gender was found. Implications for clinicians were discussed.

  11. Peer Interactions and Sociometric Status of High School Students with Moderate or Severe Disabilities in General Education Classrooms.

    Science.gov (United States)

    Mu, Keli; Siegel, Ellin B.; Allinder, Rose M.

    2000-01-01

    A study examined the social status of six high school students with moderate or severe disabilities in general education cooking classes. Although no participants were classified as popular among their peers, the majority obtained average social status ratings. Students with disabilities were involved in fewer social interactions than their peers.…

  12. Simultaneous anterior cruciate ligament reconstruction and dome-shaped high tibial osteotomy for severe medial compartment osteoarthritis of the knee

    Directory of Open Access Journals (Sweden)

    Nobuyuki Kumahashi

    2016-10-01

    Conclusion: An ACL reconstruction combined with a dome-shaped high tibial osteotomy using a locking plate is one option for treating an aged athlete with ACL deficiency and severe medial compartment osteoarthritis, and can allow the athlete to return to sports activity.

  13. Investigation of the time-dependent wear behavior of veneering ceramic in porcelain fused to metal crowns during chewing simulations.

    Science.gov (United States)

    Guo, Jiawen; Tian, Beimin; Wei, Ran; Wang, Weiguo; Zhang, Hongyun; Wu, Xiaohong; He, Lin; Zhang, Shaofeng

    2014-12-01

    The excessive abrasion of occlusal surfaces in ceramic crowns limits the service life of restorations and their clinical results. However, little is known about the time-dependent wear behavior of ceramic restorations during the chewing process. The aim of this in vitro study was to investigate the dynamic evolution of the wear behavior of veneering porcelain in PFM crowns as wear progressed, as tested in a chewing simulator. Twenty anatomical metal-ceramic crowns were prepared using Ceramco III as the veneering porcelain. Stainless steel balls served as antagonists. The specimens were dynamically loaded in a chewing simulator with 350N up to 2.4×10(6) loading cycles, with additional thermal cycling between 5 and 55°C. During the testing, several checkpoints were applied to measure the substance loss of the crowns' occlusal surfaces and to evaluate the microstructure of the worn areas. After 2.4×10(6) cycles, the entire wear process of the veneering porcelain in the PFM crowns revealed three wear stages (running-in, steady and severe wear stages). The occlusal surfaces showed traces of intensive wear on the worn areas during the running-in wear stage, and they exhibited the propagation of cracks in the subsurface during steady wear stage. When the severe wear stage was reached, the cracks penetrated the ceramic layer, causing the separation of porcelain pieces. It also exhibited a good correlation among the microstructure, the wear loss and the wear rate of worn ceramic restorations. The results suggest that under the conditions of simulated masticatory movement, the wear performance of the veneering porcelain in PFM crowns indicates the apparent similarity of the tribological characteristics of the traditional mechanical system. Additionally, the evaluation of the wear behavior of ceramic restorations should be based on these three wear stages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Cross-modal extinction in a boy with severely autistic behaviour and high verbal intelligence.

    Science.gov (United States)

    Bonneh, Yoram S; Belmonte, Matthew K; Pei, Francesca; Iversen, Portia E; Kenet, Tal; Akshoomoff, Natacha; Adini, Yael; Simon, Helen J; Moore, Christopher I; Houde, John F; Merzenich, Michael M

    2008-07-01

    Anecdotal reports from individuals with autism suggest a loss of awareness to stimuli from one modality in the presence of stimuli from another. Here we document such a case in a detailed study of A.M., a 13-year-old boy with autism in whom significant autistic behaviours are combined with an uneven IQ profile of superior verbal and low performance abilities. Although A.M.'s speech is often unintelligible, and his behaviour is dominated by motor stereotypies and impulsivity, he can communicate by typing or pointing independently within a letter board. A series of experiments using simple and highly salient visual, auditory, and tactile stimuli demonstrated a hierarchy of cross-modal extinction, in which auditory information extinguished other modalities at various levels of processing. A.M. also showed deficits in shifting and sustaining attention. These results provide evidence for monochannel perception in autism and suggest a general pattern of winner-takes-all processing in which a stronger stimulus-driven representation dominates behaviour, extinguishing weaker representations.

  15. Structure and mechanical properties of a high-carbon steel subjected to severe deformation

    Science.gov (United States)

    Gorkunov, E. S.; Zadvorkin, S. M.; Goruleva, L. S.; Makarov, A. V.; Pecherkina, N. L.

    2017-10-01

    The structure and mechanical properties of a high-carbon eutectic steel subjected to the cold plastic deformation by hydrostatic extrusion in a wide range of true strain have been studied. Using scanning and transmission electron microscopy, it has been shown that the formation of cellular, fragmented, and submicrocrystalline structures occurs in the ferritic constituent of the pearlite structure of the steel upon extrusion. This is a consequence of the occurrence of dynamic recovery and continuous dynamic and post-dynamic recrystallization, which cause a decrease in the density of free dislocations at the true strain of more than 1.62. The partial dissolution of the carbide phase is also observed. It has been found that, at a true strain of up to 0.81, the strength properties of the investigated steel are determined mainly by subgrain, dislocation, and precipitation mechanisms of the strengthening; in the deformation range of 0.81-1.62, the role of the grainboundary strengthening increases. At strains above 1.62, grain-boundary strengthening is a prevailing mechanism in the formation of the level of strength properties of the extruded U8A steel. The ultimate tensile strength and yield stress over the entire strain range only uniquely correlate with the density of highangle boundaries; the dependences of the strength characteristics on other structural parameters are not monotonic.

  16. Marginal Assessment of Crowns by the Aid of Parallel Radiography

    Directory of Open Access Journals (Sweden)

    Farnaz Fattahi

    2015-03-01

    Full Text Available Introduction: Marginal adaptation is the most critical item in long-term prognosis of single crowns. This study aimed to assess the marginal quality as well asthe discrepancies in marginal integrity of some PFM single crowns of posterior teeth by employing parallel radiography in Shiraz Dental School, Shiraz, Iran. Methods: In this descriptive study, parallel radiographies were taken from 200 fabricated PFM single crowns of posterior teeth after cementation and before discharging the patient. To calculate the magnification of the images, a metallic sphere with the thickness of 4 mm was placed in the direction of the crown margin on the occlusal surface. Thereafter, the horizontal and vertical space between the crown margins, the margin of preparations and also the vertical space between the crown margin and the bone crest were measured by using digital radiological software. Results: Analysis of data by descriptive statistics revealed that 75.5% and 60% of the cases had more than the acceptable space (50µm in the vertical (130±20µm and horizontal (90±15µm dimensions, respectively. Moreover, 85% of patients were found to have either horizontal or vertical gap. In 77% of cases, the margins of crowns invaded the biologic width in the mesial and 70% in distal surfaces. Conclusion: Parallel radiography can be expedient in the stage of framework try-in to yield some important information that cannot be obtained by routine clinical evaluations and may improve the treatment prognosis

  17. The repair of preveneered posterior stainless steel crowns.

    Science.gov (United States)

    Yilmaz, Yucel; Gurbuz, Taskin; Eyuboglu, Ozge; Belduz, Nihal

    2008-01-01

    This study's purposes were to determine the shear bond strength (SBS) for and to perform dye penetration (microleakage) and scanning electron microscopy (SEM) evaluations of preveneered posterior stainless steel crowns (SSCs) that were repaired using 2 different materials. Twenty-two crowns were used. They were stored in artificial saliva for 30 days and then thermocycled. A force was applied on the crowns' occlusal surfaces until the original veneer material appeared to be fractured. The fracture types and S8S values were recorded. The crowns were then repaired using Panavia opaque cement and Tetric Flow or Monoopaque and Tetric Flow. Twenty of the repaired crowns were subjected to dye penetration and SBS tests, and the remaining 2 were evaluated using SEM. Statistical analysis revealed no statistically significant differences in the results of either the S8S or the dye penetration test (P = .58 and P = 38, respectively). A statistically significant difference was found between original and repaired crowns regarding fracture extent (P = .02), but not failure type (P = .08). SEM evaluation showed that there was no observable gap at the interface of the original or repaired materials and the stainless steel base. Preveneered posterior stainless steel crowns may be repaired using either repair material types tested here.

  18. Selective crystallization of cations with crown ethers; Selektive Kristallisation von Kationen mit Kronenethern

    Energy Technology Data Exchange (ETDEWEB)

    Heffels, Dennis Egidius

    2014-07-04

    The aim of this work was to study the selectivity and preferences of the incorporation of differently sized cations in the cavities of various crown ethers and the characterization of the resulting compounds. The coordination preferences of crown ethers with different cavities have long been known, and the impact of other effects on the structure formation have increasingly become the focus of attention. In this work a comparative overview of the coordination preferences depending on various factors was undertaken. The focus was mainly on the variation of the cavity of the crown ether in the presence of differently sized cations. In addition, the effects of the solvent and differently coordinating anions have been investigated. Within the framework of this work, basic coordination preferences could be detected with rare earth nitrates, which are affected particularly by the choice of the solvent. The formation of different types of structures could be controlled by varying the conditions such that the incorporation of the cation in the cavity of the crown ether was influenced and the formation of a particular type of structure can be influenced partly by the choice of solvent. In this case no direct preferences for the incorporation into the cavity of the crown ether in relation to the cation size were observed for rare earth cations. However, the coordination of the crown ether leads in each case - for lanthanides - to rather high coordination numbers. A total of five new rare earth complexes and two structural variants could be observed with crown ethers. In the study of the selectivity of the incorporation into the cavity, known structures were also reproduced and further structures were characterized but the crystal structures not entirely solved. With the use of monovalent cations such as potassium, lithium or silver a total of nine new compounds could be synthesized, while no clear preferences for the incorporation of certain cations were detected. The

  19. Crown ethers and phase transfer catalysis in polymer science

    CERN Document Server

    Carraher, Charles

    1984-01-01

    Phase transfer catalysis or interfacial catalysis is a syn­ thetic technique involving transport of an organic or inorganic salt from a solid or aqueous phase into an organic liquid where reaction with an organic-soluble substrate takes place. Over the past 15 years there has been an enormous amount of effort invested in the development of this technique in organic synthe­ sis. Several books and numerous review articles have appeared summarizing applications in which low molecular weight catalysts are employed. These generally include either crown ethers or onium salts of various kinds. While the term phase transfer catalysis is relatively new, the concept of using a phasetrans­ fer agent (PTA) is much older~ Both Schnell and Morgan employed such catalysts in synthesis of polymeric species in the early 1950's. Present developments are really extensions of these early applications. It has only been within the last several years that the use of phase transfer processes have been employed in polymer synthesis...

  20. Optimizing preparation design for metal-free composite resin crowns.

    Science.gov (United States)

    Ohlmann, Brigitte; Gruber, Rudolf; Eickemeyer, Grit; Rammelsberg, Peter

    2008-09-01

    Although composite resin materials are used for posterior crown restorations, the influence of preparation design, material thickness, convergence angle, and method of cementation on fracture resistance remains unclear. The purpose of this in vitro study was to test the hypothesis that minimal preparation designs provide an acceptable level of fracture resistance for posterior composite resin crowns. Nonreinforced Artglass composite resin crowns (n=128) were fabricated on human molars in 16 test groups (n=8). Axial tooth preparation included a 1-mm-deep shoulder or a 0.5-mm chamfer preparation, whereas occlusal reduction was either 0.5 mm or 1.3 mm. The total angle of convergence was 4 or 11 degrees and the crowns were cemented either with glass ionomer cement (Ketac Cem) or resin cement (2bond2). After 10,000 thermal cycles, crowns were vertically loaded until failure occurred; load was measured in newtons. Statistical analysis was performed by a 4-way ANOVA (alpha=.05). Statistical analysis revealed significant effects of occlusal thickness (Pcrowns. For composite resin crowns with an occlusal thickness of 0.5 mm, the resistance to fracture was lower than for crowns with a 1.3-mm thickness. Fracture resistance was greater when resin cement was used, and greater for the chamfer finish line than for the shoulder finish line. Use of a greater total convergence angle reduced fracture resistance. Fracture resistance of composite resin crowns was significantly improved by increasing the occlusal thickness of the crowns, by using resin cement, and by reducing the total convergence angle.

  1. Survival Predictions of Ceramic Crowns Using Statistical Fracture Mechanics.

    Science.gov (United States)

    Nasrin, S; Katsube, N; Seghi, R R; Rokhlin, S I

    2017-05-01

    This work establishes a survival probability methodology for interface-initiated fatigue failures of monolithic ceramic crowns under simulated masticatory loading. A complete 3-dimensional (3D) finite element analysis model of a minimally reduced molar crown was developed using commercially available hardware and software. Estimates of material surface flaw distributions and fatigue parameters for 3 reinforced glass-ceramics (fluormica [FM], leucite [LR], and lithium disilicate [LD]) and a dense sintered yttrium-stabilized zirconia (YZ) were obtained from the literature and incorporated into the model. Utilizing the proposed fracture mechanics-based model, crown survival probability as a function of loading cycles was obtained from simulations performed on the 4 ceramic materials utilizing identical crown geometries and loading conditions. The weaker ceramic materials (FM and LR) resulted in lower survival rates than the more recently developed higher-strength ceramic materials (LD and YZ). The simulated 10-y survival rate of crowns fabricated from YZ was only slightly better than those fabricated from LD. In addition, 2 of the model crown systems (FM and LD) were expanded to determine regional-dependent failure probabilities. This analysis predicted that the LD-based crowns were more likely to fail from fractures initiating from margin areas, whereas the FM-based crowns showed a slightly higher probability of failure from fractures initiating from the occlusal table below the contact areas. These 2 predicted fracture initiation locations have some agreement with reported fractographic analyses of failed crowns. In this model, we considered the maximum tensile stress tangential to the interfacial surface, as opposed to the more universally reported maximum principal stress, because it more directly impacts crack propagation. While the accuracy of these predictions needs to be experimentally verified, the model can provide a fundamental understanding of the

  2. Residual thermal stress simulation in three-dimensional molar crown systems: a finite element analysis.

    Science.gov (United States)

    Bonfante, Estevam A; Rafferty, Brian T; Silva, Nelson R F A; Hanan, Jay C; Rekow, Elizabeth Dianne; Thompson, Van P; Coelho, Paulo G

    2012-10-01

    To simulate coefficient of thermal expansion (CTE)-generated stress fields in monolithic metal and ceramic crowns, and CTE mismatch stresses between metal, alumina, or zirconia cores and veneer layered crowns when cooled from high temperature processing. A 3D computer-aided design model of a mandibular first molar crown was generated. Tooth preparation comprised reduction of proximal walls by 1.5 mm and of occlusal surfaces by 2.0 mm. Crown systems were monolithic (all-porcelain, alumina, metal, or zirconia) or subdivided into a core (metallic, zirconia, or alumina) and a porcelain veneer layer. The model was thermally loaded from 900°C to 25°C. A finite element mesh of three nodes per edge and a first/last node interval ratio of 1 was used, resulting in approximately 60,000 elements for both solids. Regions and values of maximum principal stress at the core and veneer layers were determined through 3D graphs and software output. The metal-porcelain and zirconia-porcelain systems showed compressive fields within the veneer cusp bulk, whereas alumina-porcelain presented tensile fields. At the core/veneer interface, compressive fields were observed for the metal-porcelain system, slightly tensile for the zirconia-porcelain, and higher tensile stress magnitudes for the alumina-porcelain. Increasingly compressive stresses were observed for the metal, alumina, zirconia, and all-porcelain monolithic systems. Variations in residual thermal stress levels were observed between bilayered and single-material systems due to the interaction between crown configuration and material properties. © 2012 by the American College of Prosthodontists.

  3. Assessing factors causing severe injuries in crashes of high-deck buses in long-distance driving on freeways.

    Science.gov (United States)

    Chu, Hsing-Chung

    2014-01-01

    High-deck buses that have a higher center of gravity traveling at an excessive speed have a higher likelihood of causing serious and fatal accidents when drivers lose control of the vehicle. In addition, drivers who suffer from fatigue in long-distance driving increase the likelihood of serious accident. This paper examines the effects of risk factors contributing to severe crashes associated with high-deck buses used for long-distance driving on freeways. An ordered logit and latent class models are used to examine significant factors on the severity of injuries in crashes related to high-deck buses. Driver fatigue, drivers or passengers not wearing a seat belt, reckless driving, drunk driving, crashes occurred between midnight and dawn, and crashes occurred at interchange ramps were found to significantly affect the severity of injuries in crashes involving high-deck buses. Safety policies to prevent severe injuries in crashes involving high deck buses used for long-distance runs on freeways include: (1) restricting drivers from exceeding the limit of daily driving hours and mandating sufficient rest breaks; (2) installing an automatic sleep-warning device in the vehicle; (3) drivers with obstructive sleep apnea syndrome or sleep disorders should be tested and treated before they are allowed to perform long hours of driving tasks; (4) educating the public or even amending the seatbelt legislation to require all passengers to wear a seat belt and thus reduce the chance of ejection from a high-deck bus and prevent serious injuries in a crash while traveling at a higher speed on freeways. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Phylogeography of the crown-of-thorns starfish: genetic structure within the Pacific species

    Science.gov (United States)

    Vogler, C.; Benzie, J. A. H.; Tenggardjaja, K.; Ambariyanto; Barber, P. H.; Wörheide, G.

    2013-06-01

    Previous studies of the population genetic structure of the corallivorous crown-of-thorns starfish (COTS) Acanthaster planci in the Pacific Ocean showed high levels of gene flow that were assumed to reflect a high dispersal potential. However, the phylogeographic analyses of the Pacific crown-of-thorns starfish species of this study, using the highly variable mitochondrial control region and the most complete geographic coverage to date, contradict this view. Results show high levels of overall genetic structure (ΦST = 0.198), suggesting a complex history of range restrictions and expansions, a pattern that we hypothesize results from changes in topography and oceanography associated with sea-level changes. However, results also show signatures of ongoing gene flow between populations isolated in the past and high levels of genetic connectivity even among distant populations. Combined, these results indicate that while there are significant limits to genetic exchange among populations among Pacific Ocean populations of the crown-of-thorns starfish, the high larval dispersal potential of this species is often achieved as well.

  5. Simplified Fabrication of an Esthetic Implant-Supported Crown With a Novel CAD/CAM Glass Ceramic.

    Science.gov (United States)

    Conejo, Julián; Blatz, Markus B

    2016-06-01

    Implant therapy and CAD/CAM technologies are advancing quickly, providing predictable esthetic and functional treatment options. A recent development involves the use of zirconia-reinforced lithium-silicate ceramic for fabrication of implant-supported restorations. Suitable for monolithic crowns, the material provides the optical advantages of a silicate ceramic with improved physical strength. Several prerequisites, however, are necessary to fabricate screw-retained monolithic restorations in the anterior maxilla. This case report demonstrates the clinical steps to fabricate a monolithic ceramic CAD/CAM crown on an immediately placed dental implant in the esthetic zone.

  6. Unique case of a geminated supernumerary tooth with trifid crown

    Energy Technology Data Exchange (ETDEWEB)

    Ather, Amber; Ather, Hunaiza; Sheth, Sanket Milan; Muliya, Vidya Saraswathi [Manipal College of Dental Sciences, Manipal (Korea, Republic of)

    2012-09-15

    Gemination, a relatively uncommon dental anomaly, is characterized by its peculiar representation as a tooth with a bifid crown and a common root and root canal. It usually occurs in primary dentition. To come across gemination in a supernumerary tooth is a rare phenomenon. The purpose of this paper is to present a unique case of hyperdontia wherein gemination in an impacted supernumerary tooth resulted in a trifid crown unlike the usual bifid crown. The role of conventional radiographs as well as computed tomography, to accurately determine the morphology and spatial location, and to arrive at a diagnosis, is also emphasized in this paper.

  7. Re/crowning the Jowo Śākyamuni

    DEFF Research Database (Denmark)

    Warner, Cameron

    2011-01-01

    of ritual observance and visions received.  In 1409, Tsongkhapa Lozang Drakpa  (1357-1419) crowned the Jowo, changing his doctrinal and iconographic representations.  I connect the controversy surrounding Tsongkhapa's decision to re/crown the Jowo in 1409 to the significance placed on authenticity......, firstness, and ritual efficacy in Tibetan cosmology.  I follow the history of the Jowo's crown into the present, including the voices of those Tibetans who blame the 1951 Chinese invasion of Tibet on repercussions of Tsongkhapa's controversial decision.  A multidisciplinary perspective, combining texts...

  8. Numerical simulation of severe water ingress accidents in a modular high temperature gas cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zuoyi; Scherer, W.

    1996-01-01

    This report analyzes reverse water ingress accidents in the SIEMENS 200 MW Modular Pebble-Bed High Temperature Gas Cooled Reactor (HTR-MODULE) under the assumption of no active safety protection systems in order to find the safety margins of the current HTR-MODULE design and to realize a catastrophe-free nuclear technology. A water, steam and helium multi-phase cavity model is developed and implemented in the DSNP simulation system. The DSNP system is then used to simulate the primary and secondary circuit of a HTR-MODULE power plant. Comparisons of the model with experiments and with TINTE calculations serve as validation of the simulation. The analysis of the primary circuit tries to answer the question how fast the water enters the reactor core. It was found that the maximum H{sub 2}O concentration increase in the reactor core is smaller than 0.3 kg/(m{sup 3}s). The liquid water vaporization in the steam generator and H{sub 2}O transport from the steam generator to the reactor core reduce the ingress velocity of the H{sub 2}O into the reactor core. In order to answer the question how much water enters the primary circuit, the full cavitation of the feed water pumps is analyzed. It is found that if the secondary circuit is depressurized enough, the feed water pumps will be inherently stopped by the full cavitation. This limits the water to be pumped from the deaerator to the steam generator. A comprehensive simulation of the MODUL-HTR power plant then shows that the H{sub 2}O inventory in the primary circuit can be limited to about 3000 kg. The nuclear reactivity increase caused by the water ingress leads to a fast power excursion, which, however, is inherently counterbalanced by negative feedback effects. Concerning the integrity of the fuel elements, the safety relevant temperature limit of 1600 C was not reached in any case. (orig.) [Deutsch] Dieser Bericht analysiert schwere Wassereinbruch-Stoerfaelle im 200 MW modularen Kugelhaufen-Hochtemperaturreaktor (HTR

  9. Homeostatic regulation of sleep in the white-crowned sparrow (Zonotrichia leucophrys gambelii

    Directory of Open Access Journals (Sweden)

    Cirelli Chiara

    2008-05-01

    Full Text Available Abstract Background Sleep is regulated by both a circadian and a homeostatic process. The homeostatic process reflects the duration of prior wakefulness: the longer one stays awake, the longer and/or more intense is subsequent sleep. In mammals, the best marker of the homeostatic sleep drive is slow wave activity (SWA, the electroencephalographic (EEG power spectrum in the 0.5–4 Hz frequency range during non-rapid eye movement (NREM sleep. In mammals, NREM sleep SWA is high at sleep onset, when sleep pressure is high, and decreases progressively to reach low levels in late sleep. Moreover, SWA increases further with sleep deprivation, when sleep also becomes less fragmented (the duration of sleep episodes increases, and the number of brief awakenings decreases. Although avian and mammalian sleep share several features, the evidence of a clear homeostatic response to sleep loss has been conflicting in the few avian species studied so far. The aim of the current study was therefore to ascertain whether established markers of sleep homeostasis in mammals are also present in the white-crowned sparrow (Zonotrichia leucophrys gambelii, a migratory songbird of the order Passeriformes. To accomplish this goal, we investigated amount of sleep, sleep time course, and measures of sleep intensity in 6 birds during baseline sleep and during recovery sleep following 6 hours of sleep deprivation. Results Continuous (24 hours EEG and video recordings were used to measure baseline sleep and recovery sleep following short-term sleep deprivation. Sleep stages were scored visually based on 4-sec epochs. EEG power spectra (0.5–25 Hz were calculated on consecutive 4-sec epochs. Four vigilance states were reliably distinguished based on behavior, visual inspection of the EEG, and spectral EEG analysis: Wakefulness (W, Drowsiness (D, slow wave sleep (SWS and rapid-eye movement (REM sleep. During baseline, SWA during D, SWS, and NREM sleep (defined as D and SWS

  10. Effects of bark beetle attack on canopy fuel flammability and crown fire potential in lodgepole pine and Engelmann spruce forests

    Science.gov (United States)

    Wesley G. Page; Martin E. Alexander; Michael J. Jenkins

    2015-01-01

    Large wildland fires in conifer forests typically involve some degree of crowning, with their initiation and propagation dependent upon several characteristics of the canopy fuels. Recent outbreaks of mountain pine beetle (Dendroctonus ponderosae Hopkins) in lodgepole pine (Pinus contorta Dougl. var. latifolia E ngelm.) forests and spruce beetle (Dendroctonus...

  11. Screening of a dry bean Andean diversity panel for potential sources of resistance to Rhizoctonia crown and root rot

    Science.gov (United States)

    Rhizoctonia crown and root rot (RCRR), caused by Rhizoctonia solani, is a major problem in most sugar beet production areas and can cause substantial losses in both yield and quality. Over the last decade, it has become the most prevalent root disease of sugar beet in Michigan and several other regi...

  12. A technique for retrofitting a metal ceramic crown to an attachment-retained removable partial denture: a clinical report.

    Science.gov (United States)

    Uludag, Bulent; Gonuldas, Fehmi; Tokar, Emre; Sahin, Volkan

    2015-02-01

    In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades. Various types of extracoronal attachments are commonly used in combination with fixed partial dentures and RPDs to achieve retention and stability. Fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention are common reasons for a failed attachment-retained RPD. Another complication of metal ceramic crowns with precision attachment is decementation of the crowns. When fixed components of the attachment-retained RPD fail, the traditional treatment approach requires remaking both the fixed and removable components of the attachment-retained RPD. This technique describes retrofitting of a metal ceramic crown to a resilient attachment-retained RPD. © 2014 by the American College of Prosthodontists.

  13. Single detection of human bocavirus 1 with a high viral load in severe respiratory tract infections in previously healthy children.

    Science.gov (United States)

    Zhou, Lili; Zheng, Shouyan; Xiao, Qiuyan; Ren, Luo; Xie, Xiaohong; Luo, Jian; Wang, Lijia; Huang, Ailong; Liu, Wei; Liu, Enmei

    2014-07-30

    Human bocavirus is a newly discovered parvovirus. Multiple studies have confirmed the presence of human bocavirus1 (HBoV1) in respiratory tract samples of children. The viral load, presentation of single detection and its role as a causative agent of severe respiratory tract infections have not been thoroughly elucidated. We investigated the presence of HBoV1 by quantitative polymerase chain reaction (PCR) of nasopharyngeal aspirate specimens from 1229 children hospitalized for respiratory tract infections. The samples were analyzed for 15 respiratory viruses by PCR and 7 respiratory viruses by viral culture. At least one virus was detected in 652 (53.1%) of 1229 children, and two or more viruses were detected in 266 (21.6%) children. HBoV1 was detected in 127 children (10.3%), in which 66/127 (52%) of the cases were the only HBoV1 virus detected. Seasonal variation was observed with a high HBoV1 infection rate in summer. A cutoff value of 107 copies/mL was used to distinguish high and low HBoV1 viral loads in the nasopharyngeal aspirates. High viral loads of HBoV1 were noted predominantly in the absence of other viral agents (28/39, 71.8%) whereas there was primarily co-detection in cases of low HBoV1 viral loads (50/88, 56.8%). There were no differences in the clinical symptoms and severity between HBoV1 single detection and co-detection. In cases of HBoV1 single detection, the high viral load group was more prevalent among children with dyspnea and wheezing than was the low viral load group (42.9% vs. 23.7%, P = 0.036; 60.7% vs. 31.6%, P = 0.018). In clinical severity, a significant difference was recorded (25.0% vs. 5.3%, P = 0.003) between high viral load and low viral load groups. Of the HBoV1 positive patients associated with severe respiratory tract infections, 10/18 (55.6%) patients belonged to the HBoV1 high viral load group, and 7/10 (70%) patients had cases of HBoV1 single detection. HBoV1 at a high viral load is not frequently found in co

  14. Calix[4]arene-(2,3-naphthylene-crown-6,crown-6) as an extraordinarily efficient macrocyclic receptor for the univalent thallium cation

    Science.gov (United States)

    Makrlík, Emanuel; Böhm, Stanislav; Kvíčalová, Magdalena; Vaňura, Petr; Asfari, Zouhair

    2015-11-01

    On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Tl+ (aq) + 1.Cs+ (nb) ? 1.Tl+ (nb) + Cs+ (aq) taking place in the two-phase water-nitrobenzene system (1 = calix[4]arene-(2,3-naphthylene-crown-6,crown-6); aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex(Tl+,1.Cs+) = 0.3 ± 0.1. Further, the extremely high stability constant of the 1.Tl+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb(1.Tl+) = 10.0 ± 0.2. Finally, applying quantum mechanical calculations, the most probable structure of the cationic complex species 1.Tl+ was derived. In the resulting complex, the 'central' cation Tl+ is bound by eight strong bonds to six oxygen atoms of the crown-6 moiety and to two carbons from the respective two benzene rings of the parent ligand 1 via cation-π interaction. The interaction energy, E(int), of the considered 1.Tl+ complex was found to be -305.7 kJ/mol, also confirming the formation of this cationic species.

  15. Retention force of secondary crowns to copings after temporary cementation: the effect of crown material and luting agent.

    Science.gov (United States)

    Mundt, Torsten; Heinemann, Friedhelm; Golecki, Gudrun; Schwahn, Christian; Biffar, Reiner

    2010-12-01

    Tooth-implant supported restorations can be temporarily cemented if the natural abutments are protected by permanently cemented copings. This in vitro study investigated the retention forces of pure titanium crowns to milled titanium alloy copings and of cobalt-chromium crowns to copings made of electroplated gold after cementation with different luting agents. Five specimens per group were cemented with acrylic-urethane cement (inner crown surface preisolated with petroleum jelly) and provisional zinc oxide cement. The retention was measured using a universal testing machine and a dental device for crown removal. The differences between groups were compared using analysis of variance. The pull-off forces for the cobalt-chromium secondary crowns cemented on gold copings using zinc oxide cement were significantly higher (mean=144.5 N) than the other crown-cement combinations (32.2-54.4 N), which showed no significant differences in the retention force. The impulse number and magnitude of the dental device was usually low and showed no substantial differences between the crown-cement combinations. It can be concluded that the results of the clinical removal method for prostheses differ from the results of the pull-off test. The question which luting agent is the better choice for retrievable restorations remains unanswered without further clinical and laboratory studies.

  16. Prevalence and severity of the premenstrual syndrome. Effects of foods and beverages that are sweet or high in sugar content.

    Science.gov (United States)

    Rossignol, A M; Bonnlander, H

    1991-02-01

    The objective of this study was to evaluate whether certain foods and beverages that are high in sugar content or taste sweet are related to the prevalence and severity of the premenstrual syndrome. Specifically, we sought to evaluate whether consumption of "junk foods", chocolate, caffeine-free cola, fruit juices or alcoholic beverages might exert an effect on the premenstrual syndrome apart from any effects of daily consumption of beverages that are high in caffeine (caffeine-containing coffee, tea and colas). The study was based on 853 responses to a questionnaire probing menstrual and premenstrual health and certain daily dietary practices; it was mailed to female university students in Oregon. An analysis of the data revealed that the consumption of chocolate, but not of other junk foods, was related to the prevalence of the premenstrual syndrome among women with more severe premenstrual symptoms. Likewise, the consumption of alcoholic beverages (all alcoholic beverages and beer only) was related to the prevalence of the premenstrual syndrome among women with more severe symptoms, as were both fruit juice and caffeine-free soda. None of the associations was substantially altered when the daily consumption of beverages high in caffeine content was controlled for. Taken together, these data suggest that the consumption of foods and beverages that are high in sugar content or taste sweet is associated with prevalence of the premenstrual syndrome.

  17. The principles for creation of fire-prevention forest belts with barriers of deciduous species for protection from crown fires

    Directory of Open Access Journals (Sweden)

    S. N. Sannikov

    2017-10-01

    Full Text Available The article discuss one of the priority security problems in Russia, which is elaboration of the strategic system of the forest and society safeguards from catastrophic forest crown fires in connection with rapid climate warming. It is postulated, that a most effective and reliable barrier for the dispersal of the intensive crown fire in a coniferous forest massive can be a sufficiently wide strip of deciduous tree species – «deciduous forest barrier», which has phytomass capable of absorbing crown fire energy and transforming them to surface fire, which may be extinguished by technical means. The actuality of the natural study of the transition parameters from the crown fire to surface fire has been noted, depending on climate, fire intensity and the deciduous barrier structure. The results of the quantitative natural investigation of the consequences of catastrophic crown fires of 2004 in the island pine forests of forest-steppe zone in Kurgan Oblast, which passed through the belt of 50–70 year-old birch stands of middle density, has been cited and formalized mathematically. It has been shown, that 150 m width of deciduous forest barrier is necessary as a minimum for the reliable transition of the high intensive front crown fire to surface fire in the forest-steppe conditions of the Western Siberia, but this width reduces with a decreasing heating effect. It has been proposed to create the complex fire-prevention forest belts of different construction for the protection of forests, industrial objects and settlements. Besides a basic deciduous barrier, their structure should include technologically necessary buffer zones and zones for the localization and extinguishing surface fire, which stop a crown fire. It has been recommended to use natural regeneration of deciduous tree species, as a most effective and non-deficient method for the creation of deciduous forest barriers in the predominant forest types, except the lichen pine forests

  18. An up to 50-year follow-up of crown and veneer survival in a dental practice.

    Science.gov (United States)

    Olley, Ryan C; Andiappan, Manoharan; Frost, Peter

    2017-09-29

    Indirect restorations are an important treatment in dental practice, but long-term survival studies are lacking. The purpose of this retrospective study was to report on the outcome of indirect restorations, which were followed up annually for up to 50 years in a dental practice. A retrospective survival study was undertaken at a mixed National Health Service (NHS)/private dental practice in London, UK. Data were collected for restorations placed between 1966 and 1996 by 1 experienced operator. It was a requirement that patients had been followed up annually with clinical and radiographic examinations for up to 50 years. Patients were enrolled on a strict preventive policy and had excellent oral hygiene. Oral hygiene, restoration location, sensitivity, occlusion, and other details (preparation design, taper, cement used) were recorded. Restoration outcome was recorded as successful and surviving, unknown, or failed. The data were described descriptively. Kaplan-Meier survival curves and hazard curves were used to assess the survival of crowns and the probability of failure over time. A total of 223 restorations were placed in 47 patients between 1966 and 1996 and reviewed annually for up to 50 years (until 2016). These restorations included 154 metal-ceramic crowns (101 posterior and 53 anterior), 25 posterior gold crowns, 22 anterior ceramic veneers, and 22 anterior ceramic crowns. Restorations were in occlusion. The mean survival for metal-ceramic crowns was estimated as 47.53 years (95% confidence interval [CI]: 45.59-49.47 years). Failures in metal-ceramic crowns (n=6, 3.9%) were due to periapical periodontitis. The remaining restoration types had 100% survival at 50 years. This study showed that the survival of crowns and veneers is high over 50 years in clinical practice with annual follow-up and good oral hygiene. The proportion of teeth with loss of vitality, confirmed clinically and with radiographs, was minimal. Copyright © 2017 Editorial Council for the

  19. Fracture strength of porcelain fused to metal crowns made of cast, milled or laser-sintered cobalt-chromium.

    Science.gov (United States)

    Suleiman, Sozan Hama; Vult von Steyern, Per

    2013-09-01

    The aim was to compare the fracture strength of porcelain fused to metal crowns with copings fabricated in Co-Cr using different manufacturing techniques (casting, milling and laser-sintering) with crowns manufactured in a high-gold alloy. A total of 50 identical crowns were fabricated and sub-divided into five groups; cast Co-Cr, milled Co-Cr, two groups of laser-sintered Co-Cr and a control group cast in a high-gold alloy. After thermocycling (5000 cycles, 5-55°C) and pre-load (30-300 N, 10,000 cycles) the crowns were loaded until fracture. Load (N) and fracture mode were recorded. There was a significant difference (p alloy present numerically higher fracture strength than crowns made with copings fabricated in Co-Cr alloys. The difference is confirmed when analyzing the fracture surfaces, but the difference in fracture strength value is limited and is only significant with regard to one of the two laser-sintered groups.

  20. Sever's Disease

    Science.gov (United States)

    ... place on hard surfaces, such as track, basketball, soccer, and gymnastics. Sever's disease also can result from ... plate flat or high arch , which affects the angle of the heel within the foot, causing tightness ...

  1. Zirconia-Prefabricated Crowns for Pediatric Patients With Primary Dentition: Technique and Cementation for Esthetic Outcomes.

    Science.gov (United States)

    Cohn, Carla

    2016-09-01

    Traditionally, many clinicians tend to forego esthetic considerations when full-coverage restorations are indicated for pediatric patients with primary dentitions. However, the availability of new zirconia pediatric crowns and reliable techniques for cementation makes esthetic outcomes practical and consistent when restoring primary dentition. Two cases are described: a 3-year-old boy who presented with severe early childhood caries affecting both anterior and posterior teeth, and a 6-year-old boy who presented with extensive caries of his primary posterior dentition, including a molar requiring full coverage. The parents of both boys were concerned about esthetics, and the extent of decay indicated the need for full-coverage restorations. This led to the boys receiving treatment using a restorative procedure in which the carious teeth were prepared for and restored with esthetic tooth-colored zirconia crowns. In both cases, comfortable function and pleasing esthetics were achieved.

  2. Comparison of three different crown-lengthening procedures in the maxillary anterior esthetic regions.

    Science.gov (United States)

    Paolantoni, Guerino; Marenzi, Gaetano; Mignogna, Jolanda; Wang, Hom-Lay; Blasi, Andrea; Sammartino, Gilberto

    2016-01-01

    A papilla preservation crown-lengthening procedure (PPCL) was proposed for treatment of the maxillary anterior teeth (canine to canine) and compared to two traditional techniques. Thirty patients were assigned to three treatment groups: PPCL, the apically positioned flap with buccal approach (APF-B), and the apically positioned flap with buccal and palatal approach (APF-BP). Several clinical parameters were recorded at baseline and 6 months after surgery. Although no statistically significant differences were reported in many of the clinical parameters examined, APF-B and APF-BP showed a significantly higher interproximal clinical attachment loss when compared to PPCL. In the PPCL group, there was a significant increase in esthetic appraisal by the patients. Crown lengthening using a papilla-preservation flap approach and osseous recontouring is a viable alternative approach and could be useful in esthetic regions.

  3. Surgical crown lengthening in a population with human immunodeficiency virus: a retrospective analysis).

    Science.gov (United States)

    Kolhatkar, Shilpa; Mason, Suzanne A; Janic, Ana; Bhola, Monish; Haque, Shaziya; Winkler, James R

    2012-03-01

    Individuals with human immunodeficiency virus (HIV) have an increased risk of developing health problems, including some that are life threatening. Today, dental treatment for the population with a positive HIV diagnosis (HIV+) is comprehensive. There are limited reports on the outcomes of intraoral surgical therapy in patients with HIV, such as crown lengthening surgery (CLS) with osseous recontouring. This report investigates the outcome of CLS procedures performed at an urban dental school in a population of individuals with HIV. Specifically, this retrospective clinical analysis evaluates the healing response after CLS. Paper and electronic records were examined from the year 2000 to the present. Twenty-one individuals with HIV and immunosuppression, ranging from insignificant to severe, underwent CLS. Pertinent details, including laboratory values, medications, smoking history/status, and postoperative outcomes, were recorded. One such surgery is described in detail with radiographs, photographs, and a videoclip. Of the 21 patients with HIV examined after CLS, none had postoperative complications, such as delayed healing, infection, or prolonged bleeding. Variations in viral load (healing. In addition, variations in medication regimens (highly active anti-retroviral therapy [18]; on protease inhibitors [1]; no medications [2]) did not have an impact. The results of this retrospective analysis show the absence of postoperative complications after CLS in this population with HIV. Additional investigation into this area will help health care practitioners increase the range of surgical services provided to this group of patients.

  4. Composite fuselage crown panel manufacturing technology

    Science.gov (United States)

    Willden, Kurtis; Metschan, S.; Grant, C.; Brown, T.

    1992-01-01

    Commercial fuselage structures contain significant challenges in attempting to save manufacturing costs with advanced composite technology. Assembly issues, material costs, and fabrication of elements with complex geometry are each expected to drive the cost of composite fuselage structures. Boeing's efforts under the NASA ACT program have pursued key technologies for low-cost, large crown panel fabrication. An intricate bond panel design and manufacturing concepts were selected based on the efforts of the Design Build Team (DBT). The manufacturing processes selected for the intricate bond design include multiple large panel fabrication with the Advanced Tow Placement (ATP) process, innovative cure tooling concepts, resin transfer molding of long fuselage frames, and utilization of low-cost material forms. The process optimization for final design/manufacturing configuration included factory simulations and hardware demonstrations. These efforts and other optimization tasks were instrumental in reducing cost by 18 percent and weight by 45 percent relative to an aluminum baseline. The qualitative and quantitative results of the manufacturing demonstrations were used to assess manufacturing risks and technology readiness.

  5. The influence of veneering porcelain thickness of all-ceramic and metal ceramic crowns on failure resistance after cyclic loading.

    Science.gov (United States)

    Shirakura, Akihiko; Lee, Heeje; Geminiani, Alessandro; Ercoli, Carlo; Feng, Changyong

    2009-02-01

    In some clinical situations, the length of either a prepared tooth or an implant abutment is shorter than ideal, and the thickness of a porcelain crown must be increased. Thickness of the coping and the veneering porcelain should be considered to prevent mechanical failure of the crown. The purpose of this study was to investigate the influence of veneering porcelain thickness for all-ceramic and metal ceramic crowns on failure resistance after cyclic loading. All-ceramic and metal ceramic crowns (n=20) were fabricated on an implant abutment (RN Solid Abutment) for the study. Two different framework designs with 2 different incisal thicknesses of veneering porcelain (2 mm and 4 mm) were used for each all-ceramic and metal ceramic crown system, resulting in 4 experimental groups (n=10) with identically shaped crowns. The all-ceramic crown consisted of alumina (Procera AllCeram) frameworks and veneering porcelain (Cerabien), while metal ceramic crowns were made of high noble metal (Leo) frameworks and veneering porcelain (IPS Classic). All crowns were cemented on the corresponding abutments using a resin cement (Panavia 21). They were subjected to 1000 cycles of thermal cycling (5 degrees C and 55 degrees C; 5-second dwell time). The crowns were tested with a custom-designed cyclic loading apparatus which delivered simultaneous unidirectional cyclic loading at 135 degrees, vertically, at an rpm of 250, with a load of 49 N. Each specimen was loaded for 1.2 x 106 cycles or until it failed. The specimens were thoroughly evaluated for cracks and/or bulk fracture with an optical stereomicroscope (x10) and assigned a score of success, survival, or failure. The specimens without bulk fracture after cyclic loading were loaded along the long axis of the tooth, on the incisal edge, in a universal testing machine at a crosshead speed of 1.5 mm/min, until fracture. Fisher's exact test was used to compare the success and survival rate between the 2 different materials (alpha=.05

  6. Serum palivizumab level is associated with decreased severity of respiratory syncytial virus disease in high-risk infants.

    Science.gov (United States)

    Forbes, Michael L; Kumar, Veena R; Yogev, Ram; Wu, Xionghua; Robbie, Gabriel J; Ambrose, Christopher S

    2014-01-01

    Monthly doses of palivizumab, an RSV-specific monoclonal antibody, reduce RSV-related hospitalizations (RSVH) in high-risk children; however, no specific palivizumab level has been correlated with disease severity in humans. A post hoc analysis of a previous randomized, placebo-controlled trial evaluated the relationship between serum palivizumab level at the time of RSVH and disease severity. Pediatric intensive care unit (PICU) admission was the primary severity marker. Relationships were evaluated between disease severity and gestational age, age at enrollment, age at RSVH, presence of bronchopulmonary dysplasia, sex, race, multiple birth, household smoking, daycare attendance, sibling(s), family history of atopy, duration between most recent palivizumab dose and RSVH, and palivizumab level at RSVH. Forty-two (87.5%) of 48 palivizumab recipients with RSVH had palivizumab levels drawn; 11 were admitted to the PICU. Mean palivizumab levels were lower in PICU-admitted subjects (47.2 μg/mL) vs. non-PICU subjects (98.7 μg/mL; P < 0.0001); there were no statistically significant differences in other variables examined. The probability of PICU admission declined with higher palivizumab levels; there were no PICU admissions with levels ≥ 92 μg/mL. In multivariate analyses, palivizumab level was the only independent predictor of PICU admission (P = 0.009). Palivizumab level also correlated with duration of RSVH and PICU stay, supplemental oxygen use and duration, and mechanical ventilation use and duration (P < 0.05). Higher palivizumab level was associated with decreased disease severity in high-risk infants with RSVH. Findings suggest that palivizumab level has clinical relevance, and adherence to timely monthly dosing may confer additional protection among high-risk children receiving palivizumab.

  7. Percutaneous Dual-valve Intervention in a High-risk Patient with Severe Aortic and Mitral Stenosis.

    Science.gov (United States)

    Mrevlje, Blaz; Aboukura, Mohamad; Nienaber, Christoph A

    2016-01-01

    Aortic stenosis is the most frequent and mitral stenosis is the least frequent native single-sided valve disease in Europe. Patients with the combination of severe symptomatic degenerative aortic and mitral stenosis are very rare. Guidelines for the treatment of heart valve diseases are clear for single-valve situations. However, there is no common agreement or recommendation for the best treatment strategy in patients with multiple valve disease and severe concomitant comorbidities. A 76-year-old female patient with the combination of severe degenerative symptomatic aortic and mitral stenosis and several comorbidities including severe obesity, who was found unsuitable surgical candidate by the heart team and unsuitable for two-time general anesthesia in the case of two-step single-valve percutaneous approach by anesthesiologists, underwent successful percutaneous dual-valve single-intervention (transcatheter aortic valve implantation and percutaneous mitral balloon commissurotomy). Percutaneous dual-valve single-intervention is feasible in selected symptomatic high-risk patients.

  8. An extremely high bioavailability of orally administered vancomycin in a patient with severe colitis and renal insufficiency.

    Science.gov (United States)

    Yamazaki, Shingo; Suzuki, Takaaki; Suzuki, Tatsuya; Takatsuka, Hirokazu; Ishikawa, Masayuki; Hattori, Noriyuki; Fujishiro, Takeshi; Miyauchi, Hideaki; Oami, Takehiko; Ariyoshi, Noritaka; Oda, Shigeto; Matsubara, Hisahiro; Ishii, Itsuko

    2017-12-01

    Because there is little absorption of orally administered vancomycin hydrochloride (VCM) through the normal intestinal microvillus membrane, the pharmacokinetics of VCM absorbed from the digestive tract are mostly unknown. Here we report a case of severe colitis and renal insufficiency in which the serum concentration of VCM reached the supratherapeutic range after oral administration. A 54-year-old man receiving outpatient chemotherapy for rectal cancer was admitted to our hospital for severe sepsis and acute renal failure. Multimodal therapy including continuous renal replacement therapy (CRRT) and mechanical ventilation was initiated, and oral VCM administration (0.5 g every 6 h) was begun for suspected severe pseudomembranous colitis with large amounts of watery stool. Despite continued CRRT, the serum VCM concentration increased to 30.6 μg/mL after 4 days. Based on pharmacokinetic analysis, the bioavailability of VCM was estimated to be over 54.5%. Colonoscopy showed that the mucosa was severely damaged throughout the large intestine, resulting in considerable exudation of plasma and blood. This case indicates the need for careful and early monitoring during high-dose oral VCM administration to patients with severe mucosal injury and renal insufficiency. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  9. Developing and Testing a High-Fidelity Simulation Scenario for an Uncommon Life-Threatening Disease: Severe Malaria

    Directory of Open Access Journals (Sweden)

    Andrew Kestler

    2011-01-01

    Full Text Available Background. Severe malaria is prevalent globally, yet it is an uncommon disease posing a challenge to education in nonendemic countries. High-fidelity simulation (sim may be well suited to teaching its management. Objective. To develop and evaluate a teaching tool for severe malaria, using sim. Methods. A severe malaria sim scenario was developed based on 5 learning objectives. Sim sessions, conducted at an academic center, utilized METI ECS mannequin. After sim, participants received standardized debriefing and completed a test assessing learning and a survey assessing views on sim efficacy. Results. 29 participants included 3rd year medical students (65%, 3rd year EM residents (28%, and EM nurses (7%. Participants scored average 85% on questions related to learning objectives. 93% felt that sim was effective or very effective in teaching severe malaria, and 83% rated it most effective. All respondents felt that sim increased their knowledge on malaria. Conclusion. Sim is an effective tool for teaching severe malaria in and may be superior to other modalities.

  10. Probing supramolecular complexation of cetylpyridinium chloride with crown ethers

    Science.gov (United States)

    Saha, Subhadeep; Roy, Mahendra Nath

    2017-11-01

    Supramolecular complexations of cetylpyridinium chloride with three comparable cavity dimension based crown ethers, namely, dibenzo-18-crown-6, 18-crown-6 and dicyclohexano-18-crown-6 have been explored and adequately compared in acetonitrile with the help of conductivity in a series of temperatures to reveal the stoichiometry of the three host-guest complexes. Programme based mathematical treatment of the conductivity data affords association constants for complexations from which the thermodynamic parameters were derived for better comprehension about the process. The interactions at molecular level have been explained and decisively discussed by means of FT-IR and 1H NMR spectroscopic studies that demonstrate H-bond type interactions as the primarily force of attraction for the investigated supramolecular complexations.

  11. Finite Element Stress Analysis of Stainless Steel Crowns

    National Research Council Canada - National Science Library

    Attiguppe Prabhakar; Chandrashekar Yavagal; Amrita Chakraborty; S Sugandhan

    2015-01-01

      Background: Though stainless steel crowns (SSCs) have often been stated as the best restorative modality, there are limited studies demonstrating its efficacy in restoring the functional integrity of the primary dentition...

  12. Estimation of crown closure from AVIRIS data using regression analysis

    Science.gov (United States)

    Staenz, K.; Williams, D. J.; Truchon, M.; Fritz, R.

    1993-01-01

    Crown closure is one of the input parameters used for forest growth and yield modelling. Preliminary work by Staenz et al. indicates that imaging spectrometer data acquired with sensors such as the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) have some potential for estimating crown closure on a stand level. The objectives of this paper are: (1) to establish a relationship between AVIRIS data and the crown closure derived from aerial photography of a forested test site within the Interior Douglas Fir biogeoclimatic zone in British Columbia, Canada; (2) to investigate the impact of atmospheric effects and the forest background on the correlation between AVIRIS data and crown closure estimates; and (3) to improve this relationship using multiple regression analysis.

  13. Supramolecular metal complex systems based on crown-substituted tetrapyrroles

    Energy Technology Data Exchange (ETDEWEB)

    Tsivadze, Aslan Yu [Institute of Physical Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)

    2004-01-31

    The characteristic features of the structures and properties of crown-substituted porphyrinates and phthalocyaninates are considered. Interactions of these compounds with alkali metal salts yield supramolecular ensembles. The factors determining the architecture of such ensembles are described.

  14. Silica crown refractory corrosion in glass melting furnaces

    National Research Council Canada - National Science Library

    Balandis A; Nizeviciene D

    2011-01-01

    ... of glass furnaces, when the rate of corrosion of crowns were about 2 times greater. The change of these parameters, the chemical composition and formation of the microcracks in the used silica refractories material were studied...

  15. Nucleosynthesis and Energy Production in Stars: Bethe's Crowning ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 10. Nucleosyntheis and Energy Production in Stars: Bethe's Crowning Achievement. Indranil Mazumdar. General Article Volume 10 Issue 10 October 2005 pp 67-77 ...

  16. Mandibular molar crown-topography, a biological predisposing ...

    African Journals Online (AJOL)

    Mandibular molar crown-topography, a biological predisposing factor to development of caries – a post-mortem analysis of 2500 extracted lower permanent molars at the dental centre, University of Benin teaching hospital.

  17. Whole-Genome Sequences of Chlamydia psittaci Strain HJ, Isolated from Meat Pigeons with Severe Respiratory Distress and High Mortality.

    Science.gov (United States)

    Zhang, Qiang; Wu, Zongxue; Sun, Ruixue; Chu, Jun; Han, Er; Zhang, Yinxin; Ling, Yong; Gong, Yanping; Li, Dongfang; Wu, Honglong; He, Cheng; Ni, Peixiang

    2015-03-05

    The obligate intracellular Gram-negative bacterium Chlamydia psittaci causes systemic disease in psittacine birds, domestic poultry, and wild fowl. Importantly, C. psittaci may cause pneumonia, encephalitis, endocarditis, and even death in humans. The potential of pigeons as a source of human psittacosis is supported worldwide by relatively high seroconversion rates in the birds. This study reports the whole-genome sequencing of C. psittaci strain HJ, isolated from meat pigeons suffering from severe pneumonia and high mortality in 2013 in Hebei, China. Copyright © 2015 Zhang et al.

  18. Preferred low- and high-frequency compression ratios among hearing aid users with moderately severe to profound hearing loss.

    Science.gov (United States)

    Keidser, Gitte; Dillon, Harvey; Dyrlund, Ole; Carter, Lyndal; Hartley, David

    2007-01-01

    This study aimed to determine the low- and high-frequency compression ratios of a fast-acting device that were preferred by people with moderately severe to profound hearing loss. Three compression ratios (1:1, 1.8:1, and 3:1) were combined in the low and high frequencies to produce nine schemes that were evaluated pair-wise for three weeks in the field using an adaptive procedure. The evaluation was performed by 21 experienced hearing aid users with a moderately severe to profound hearing loss. Diaries and an exit interview were used to monitor preferences. Generally, the subjects preferred lower compression ratios than are typically prescribed, especially in the low frequencies. Specifically, 11 subjects preferred linear amplification in the low frequencies, and 14 subjects preferred more compression in the high than in the low frequencies. Preferences could not be predicted from audiometric data, onset of loss, or past experience with amplification. The data suggest that clients with moderately severe to profound hearing loss should be fitted with low-frequency compression ratios in the range 1:1 to 2:1 and that fine-tuning is essential.

  19. Ruthenium ammine/crown ether interactions in solution: Effects of modification of both guest and host on the strength of second-sphere complexation

    Energy Technology Data Exchange (ETDEWEB)

    Todd, M.D.; Yuhua Dong; Horney, J.; Yoon, D.I.; Hupp, J.T. (Northwestern Univ., Evanston, IL (United States))

    1993-05-12

    Charge-transfer absorption, electrochemical, and NMR-NOE studies of monomeric and dimeric (ligand-bridged) ruthenium ammine guest interactions with several crown ether hosts show that second-sphere complexation is prevalent in nitromethane as solvent and that complexation or binding constants can be varied by ca. 10[sup 8]-fold by modifying both guest and host properties. For hosts, larger binding constants are obtained with larger macrocycles and with more flexible macrocycles (i.e. dicyclohexano vs dibenzo crowns). For guests, larger binding constants are observed in higher oxidation states and in the presence of strongly electron-withdrawing ancillary ligands. In all cases, binding appears to be driven primarily by ammine hydrogen/ether oxygen (Lewis acid/base) interactions. Evidence is also found, however, for contributions from favorable benzene(crown)/pyridine(complex) interactions and (apparently) benzene(crown) [yields] Ru(III) charge-transfer (donor/acceptor) interactions. 17 refs., 3 figs., 2 tabs.

  20. Slow cooling protocol improves fatigue life of zirconia crowns.

    Science.gov (United States)

    Paula, Vitor G; Lorenzoni, Fabio C; Bonfante, Estevam A; Silva, Nelson R F A; Thompson, Van P; Bonfante, Gerson

    2015-02-01

    To compare the fatigue life and damage modes of zirconia crowns fabricated with and without framework design modification when porcelain veneered using a fast or slow cooling protocol. Composite resin replicas of a first molar full crown preparation were fabricated. Zirconia copings were milled as conventional (0.5mm even thickness, Zr-C, n=20,) or modified (lingual margin of 1.0mm thickness, 2.0mm height connected to two proximal struts of 3.5mm height, Zr-M, n=20). These groups were subdivided (n=10 each) according to the veneer cooling protocol employed: fast cooling (Zr-CFast and Zr-MFast) and slow cooling (Zr-CSlow and Zr-MSlow). Crowns were cemented and fatigued for 10(6) cycles in water. The number of cycles to failure was recorded and used to determine the interval databased 2-parameter probability Weibull distribution parameter Beta (β) and characteristic life value Eta (η). 2-parameter Weibull calculation presented β=5.53 and β=4.38 for Zr-MFast and Zr-CFast, respectively. Slow cooled crowns did not fail by completion of 10(6) cycles, thereby Weibayes calculation was applied. Increased fatigue life was observed for slow cooled crowns compared to fast cooled ones. Groups Zr-MFast and Zr-MSlow presented no statistical difference. Porcelain cohesive fractures were mainly observed in fast cooled groups. Slow cooled crowns presented in some instances inner cone cracks not reaching the zirconia/veneer interface. Improved fatigue life in tandem with the absence of porcelain fractures were observed in slow cooled crowns, regardless of framework design. Crowns fast cooled chiefly failed by porcelain cohesive fractures. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Silica crown refractory corrosion in glass melting furnaces

    OpenAIRE

    Balandis A.; Nizeviciene D.

    2011-01-01

    The critical parameters of silica refractories, such as compressive strength, bulk, density, quantity of silica, microstructure and porosity were evaluated of unused and used bricks to line the crowns of glass furnaces, when the rate of corrosion of crowns were about 2 times greater. The change of these parameters, the chemical composition and formation of the microcracks in the used silica refractories material were studied. It was established that the short time at service of containe...

  2. Mechanical performance of implant-supported posterior crowns.

    Science.gov (United States)

    de Kok, Paul; Kleverlaan, Cornelis J; de Jager, Niek; Kuijs, Ruud; Feilzer, Albert J

    2015-07-01

    The fracture of implant-supported restorations, especially of the veneering layer, is a common problem in dentistry. Monolithic ceramic or resin restorations might help solve this problem. The purpose of this in vitro study was to obtain additional insight into the risk of fracture of implant-supported restorations. Identical crowns (n=10) of 10 different ceramic and composite resin materials were cemented on conventional abutments on implant replicas embedded in polymethyl methacrylate blocks. The specimens were subjected to compressive load in a universal testing machine to record initial load to failure (ILF). Additionally, the flexural strength (FS), compressive strength (CS), and elastic modulus (E) of the investigated materials were determined. These results were used in a finite element analysis model of a composite resin and a lithium disilicate crown. Anatomic contour zirconia (Lava Plus) crowns had the highest ILF (6065 N), followed by lithium disilicate (IPS e.max) (2788 N) and the composite resin materials (Protemp 4, Majesty Flow, Telio CAD, Estenia C&B, Lava Ultimate, VITA Enamic) (2386 to 1935 N). Veneered zirconia (Lava) crowns showed the lowest ILF (1477 N). The highest FS, CS, and E were found for Lava Plus and IPS e.max. No direct relationship was found between ILF and the FS, CS, or E. The finite element analysis showed stresses that did not exceed the FS or CS of IPS e.max. The surface roughness of these crowns might have caused initial failure at relatively low stresses. In this laboratory study, monolithic implant-supported crowns showed a higher ILF than conventional veneered ceramic crowns. Monolithic ceramic restorations might perform better than composite resin crowns. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  3. Failure probability of three designs of zirconia crowns

    Science.gov (United States)

    Ramos, G. Freitas; Monteiro, E. Barbosa Carmona; Bottino, M.A.; Zhang, Y.; de Melo, R. Marques

    2015-01-01

    Objectives This study utilized a 2-parameter Weibull analysis for evaluation of lifetime of fully or partially porcelain-/glaze-veneered zirconia crowns after fatigue test. Methods Sixty first molars were selected and prepared for full-coverage crowns with three different designs(n = 20): Traditional –crowns with zirconia framework covered with feldspathic porcelain; Modified– crowns partially covered with veneering porcelain; and Monolithic–full-contour zirconia crowns. All specimens were treated with a glaze layer. Specimens were subjected to mechanical cycling (100N, 3Hz) with a piston with hemispherical tip (Ø=6 mm) until the specimens failed or up to 2×106 cycles. Every 500,000 cycles intervals, the fatigue tests were interrupted, and stereomicroscopy (10 X) was used to inspect the specimens for damage. We performed Weibull analysis of interval data to calculate the number of failures in each interval. Results The types and number of failures according to the groups were: cracking (Traditional-13, Modified-6) and chipping (Traditional-4) of the feldspathic porcelain, followed by delamination (Traditional-1) at the veneer/core interface and debonding (Monollithic-2) at the cementation interface. Weibull parameters (beta, scale; and eta, shape), with a two-sided confidence interval of 95%, were: Traditional – 1.25 and 0.9 × 106cycles; Modified– 0.58 and 11.7 × 106 cycles; and Monolithic – 1.05 and 16.5 × 106 cycles. Traditional crowns showed greater susceptibility to fatigue, the Modified group presented higher propensity to early failures, and the Monolithic group showed no susceptibility to fatigue. The Modified and Monolithic groups presented the highest number of crowns with no failures after the fatigue test. Conclusions The three crown designs presented significantly different behaviors under fatigue. The Modified and the Monolithic groups presented less probability to failure after 2×106cycles. PMID:26509988

  4. Development of post-fire crown damage mortality thresholds in ponderosa pine

    Science.gov (United States)

    James F. Fowler; Carolyn Hull Sieg; Joel McMillin; Kurt K. Allen; Jose F. Negron; Linda L. Wadleigh; John A. Anhold; Ken E. Gibson

    2010-01-01

    Previous research has shown that crown scorch volume and crown consumption volume are the major predictors of post-fire mortality in ponderosa pine. In this study, we use piecewise logistic regression models of crown scorch data from 6633 trees in five wildfires from the Intermountain West to locate a mortality threshold at 88% scorch by volume for trees with no crown...

  5. Crown Recession Patterns in Three Conifer Species of the Northern Rocky Mountains

    Science.gov (United States)

    Sean M. Garber; Robert A. Monserud; Douglas A. Maguire

    2008-01-01

    Crown length is a fundamental tree dimension for characterizing growth potential, wildlife habitat, and wood quality. The relative rates of height growth and crown recession detennine the progression of crown length over time. We investigated patterns in crown recession of three co-occurring species in the northern Rocky Mountains: western white pine (Pinus...

  6. 78 FR 63559 - Order of Suspension of Trading; In The Matter of Crown Alliance Capital Limited

    Science.gov (United States)

    2013-10-24

    ... COMMISSION Order of Suspension of Trading; In The Matter of Crown Alliance Capital Limited October 22, 2013... information concerning the securities of Crown Alliance Capital Limited (``Crown Alliance''), quoted under the ticker symbol CACL, because of questions regarding the accuracy of assertions in Crown Alliance's public...

  7. Consequences of crown shortening canine teeth in Greenland sled dogs

    DEFF Research Database (Denmark)

    Kortegaard, H E; Anthony Knudsen, T; Dahl, S

    2015-01-01

    OBJECTIVES: To evaluate the consequences of crown shortening, focusing on the prevalence of pulp exposure and periapical pathology in Greenland sled dogs that had had their canine crowns shortened at an early age. METHODS: Five cadaver heads and 54 sled dogs underwent an oral examination for dental...... fractures and pulp exposure of canines. All canines were radiographed and evaluated for periapical pathology. RESULTS: The prevalence of canine pulp exposure in 12 (5 heads and 7 dogs) crown shortened dogs was 91 · 7%, and 21 · 3% in 47 not-crown shortened dogs. A significant (P ... exposure of the canines in the crown shortened group compared to the not-crown shortened group was seen with a relative risk of 4 · 3 on a dog basis and a relative risk of 12 · 2 on a tooth basis. In dogs with pulp exposure of canines (n = 51) the prevalence of periapical pathology was 82 · 4%, but only 0...

  8. Repairing a preveneered stainless steel crown with two different materials.

    Science.gov (United States)

    Yilmaz, Yucel; Yilmaz, Asude

    2004-01-01

    The objective of this study was to determine the in vitro shear bond strength of 2 different repair materials for anterior preveneered stainless steel crowns (SSCs) after bond failure in the prefabricated veneers. Sixteen preveneered anterior SSCs were used. Each of the preveneered crowns was cemented with a luting glass ionomer cement onto cast die. Each die was placed into a mechanical testing machine. A force was applied on the veneer at the incisal edge, with a crosshead speed of 0.05 inches/minute until the initial original facial facing material fractured or dislodged. Fracture or dislodgment failure of the initial original facial facings was evaluated and photographed. Specimens were divided into 2 equal repairing procedure groups. Group 1 was repaired using Tetric Flow, a flowable resin composite. Group 2 was repaired using Major Resin, a crown and bridge veneering resin. After the repairing procedure, crowns were stored in water at room temperature for 24 hours and then thermocycled. The crowns repaired were debonded in the test machine in the same manner as the initial facial facing fracture test. The debonding failure of the repaired crowns also was evaluated and photographed. There was a statistically significant difference between the initial original veneer material and groups 1 and 2 (P stainless steel metal base.

  9. Fracture load of different crown systems on zirconia implant abutments.

    Science.gov (United States)

    Albrecht, T; Kirsten, A; Kappert, H F; Fischer, H

    2011-03-01

    The purpose of this study was to evaluate the fracture load of single zirconia abutment restorations using different veneering techniques and materials. The abutment restorations were divided into 6 groups with 20 samples each: test abutments (control group A), lithium disilicate ceramic crowns bonded on incisor abutments (group B), leucite ceramic crowns bonded on incisor abutments (group C), premolar abutments directly veneered with a fluor apatite ceramic (group D (layered) and group E (pressed)) and premolar abutments bonded with lithium disilicate ceramic crowns (group F). The fracture load of the restorations was evaluated using a universal testing machine. Half of each group was artificially aged (chewing simulation and thermocycling) before evaluating the fracture load with the exception of the test abutments. The fracture load of the test abutments was 705 ± 43N. Incisor abutments bonded with lithium disilicate or leucite ceramic crowns (groups B and C) showed fracture loads of about 580N. Premolar restorations directly veneered with fluor apatite ceramic (groups D and E) showed fracture loads of about 850N. Premolar restorations bonded with lithium disilicate ceramic crowns (group F) showed fracture loads of about 1850N. The artificial ageing showed no significant influence on the strength of the examined restorations. All ceramic crowns made of lithium disilicate glass-ceramic, adhesively bonded to premolar abutments showed the highest fracture loads in this study. However, all tested groups can withstand physiological bite forces. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

    Science.gov (United States)

    Keinan, David; Mass, Eliyahu; Zilberman, Uri

    2010-01-01

    Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ), was analyzed. An energy dispersive X-ray spectrometer (EDS) was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times) were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (P crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible. PMID:21274429

  11. Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

    Directory of Open Access Journals (Sweden)

    David Keinan

    2010-01-01

    Full Text Available Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ, was analyzed. An energy dispersive X-ray spectrometer (EDS was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (<.001. Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

  12. Absorption of nickel, chromium, and iron by the root surface of primary molars covered with stainless steel crowns.

    Science.gov (United States)

    Keinan, David; Mass, Eliyahu; Zilberman, Uri

    2010-01-01

    Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ), was analyzed. An energy dispersive X-ray spectrometer (EDS) was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times) were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (P Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

  13. A randomized clinical trial investigating the performance of two commercially available posterior pediatric preveneered stainless steel crowns: a continuation study.

    Science.gov (United States)

    Kratunova, Evelina; O'Connell, Anne C

    2014-01-01

    This study aimed to compare the clinical and radiographic success of preveneered posterior NuSmile® and Kinder Krowns® over one year and to assess the level of parental satisfaction with their esthetics. Three trained operators placed 120 crowns in a split-mouth design with a random allocation for 36 participants (mean age: 5.8 years) who received two, four, six, or eight crowns. Blind assessment of the clinical and radiographic performance of the restorations was performed by four calibrated examiners after one year. Results were analyzed by Fisher's exact test and McNemar test. Examiner reliability was determined by Cohen's kappa score. Visual analogue scale (VAS) was used to assess the level of parental satisfaction. All crowns but one were retained, and the majority (83 percent) had no facing fractures. Parental satisfaction was high (9.4/10 on the VAS). Primary maxillary first molar crowns had more occlusal facing fractures than their mandibular counterparts (P=.02). Primary mandibular second molar crowns showed more facing fractures than their maxillary counterparts (P=.008). Both types showed no statistical difference in most categories, but Kinder Krowns had more facing fractures (Pcrowns have predictable durability at 12 months while offering natural appearance to restored teeth.

  14. The comparative evaluation of the translucency of crowns fabricated with three different all-ceramic materials: an in vitro study.

    Science.gov (United States)

    Sravanthi, Y; Ramani, Y V; Rathod, Asha M; Ram, Sabita M; Turakhia, Hetal

    2015-02-01

    All-ceramic crowns with different core materials of different strength and aesthetics are available in recent years. The aesthetics of the crown depends mainly on the shade and translucency. Clinician should be aware of the quality and characteristics of these materials so that they will be able to opt for good material for successful clinical use. The aim of this study was to evaluate and compare the translucency of crowns fabricated with three different commercially available all-ceramic materials viz. Alumina - CAD-CAM Procera, Lithium disilicate - Pressable IPS e.max Press, Zirconia - CAD-CAM Lava. All-ceramic crowns (5 per each group and total of 15 samples) were made of Alumina - CAD-CAM Procera (Group I), Lithium disilicate - Pressable IPS e.max Press (Group II), Zirconia - CAD-CAM Lava (Group III) and veneered with their respective layering ceramic. Evaluation for the Translucency (CR=Yb/Yw) over the White (Yw) and Black (Yb) backgrounds at the Incisal, Middle, Cervical, Mesial and Distal thirds of each crown were done using the Spectrophotometer. The results obtained were statistically analyzed by Paired t-test (pceramic system depends on the translucency needed for successful prosthesis of artificial tooth so that it mimics patient's natural dentition. The qualitative measurement of translucency will give the evidence for the clinicians during selection of high or low value translucent tooth for successful replacement. Lithium disilicate - Pressable IPS e.max Press is having better translucency in comparison with other two materials in our study.

  15. Evaluation of fracture resistance of indirect composite resin crowns by cyclic impact test: influence of crown and abutment materials.

    Science.gov (United States)

    Sakoguchi, Kenji; Minami, Hiroyuki; Suzuki, Shiro; Tanaka, Takuo

    2013-01-01

    This study evaluated the effect of abutment materials on the fracture resistance of composite crowns for premolars. Composite crowns were fabricated using two different indirect composite resin materials (Meta Color Prime Art or Estenia C&B) and cemented onto either a metal (Castwell M.C. 12) or composite resin (Build-It FR and FibreKor) abutment with resin cement (Panavia F2.0). Twenty-four specimens were fabricated for four groups (n=6 each) and subjected to 280-N cyclic impact loading at 1.0 Hz. The number of cycles which caused the composite crown to fracture was defined as its fracture resistance. All data were statistically analyzed using ANOVA and the Bonferroni test (α=0.05). Composite crowns cemented onto resin abutments showed higher fracture resistance than those cemented onto metal abutments.

  16. Wear and repair of stainless steel crowns.

    Science.gov (United States)

    Yilmaz, Y; Kara, N Belduz; Yilmaz, A; Sahin, H

    2011-03-01

    The purpose of this study was to determine the wear of stainless steel crowns (SSCs) in children, and compare the extent of microleakage in SSCs that had been repaired using either a cermet glass-ionomer cement (GIC) or a packable composite resin (CR). For the first aim, the occlusal surface thickness of 31 harvested SSCs (21 primary first and 10 second molars) and 18 unused SSCs was measured, and then examined under scanning electron microscopy. For the second aim, standardised holes were prepared on the occlusal surfaces of 20 SSCs, and then repaired using either a cermet GIC or packable CR. After their repair, the extent of microleakage was determined using 0.5% basic fuchsin and stereomicroscopy. The thickness of all the harvested SCCs was 5.3 μm less than that of the unused SCCs (p<0.02), and there were no significant differences between the thickness and occlusal wear rates of harvested SSCs from the first and second primary molars. Although neither of the two repair materials completely prevented microleakage, the number of specimens in which microleakage occurred after repair with a cermet GIC was significantly lower than the number of specimens in which a packable CR was used (p<0.05). We concluded that the occlusal surfaces of SSCs for first and second primary molars display wear. Although perforated SSCs can be repaired using either a cermet GIC or a packable CR, less microleakage occurs in SSCs that were repaired with a cermet GIC than those with a packable CR.

  17. High prevalence of severe nausea and vomiting of pregnancy and hyperemesis gravidarum among relatives of affected individuals.

    Science.gov (United States)

    Fejzo, Marlena S; Ingles, Sue Ann; Wilson, Melissa; Wang, Wei; MacGibbon, Kimber; Romero, Roberto; Goodwin, Thomas M

    2008-11-01

    The goal of this study was to determine the prevalence of severe nausea and vomiting of pregnancy/hyperemesis gravidarum among relatives of affected individuals. Family history data were obtained on 1224 self-reported cases of hyperemesis gravidarum. Cases completed an online survey administered by the Hyperemesis Education and Research Foundation between 2003 and 2006. Approximately 28% of cases reported their mother had severe nausea and vomiting or hyperemesis gravidarum while pregnant with them. Of the 721 sisters with a pregnancy history, 137 (19%) had hyperemesis gravidarum. Among the most severe cases, those requiring total parenteral nutrition or nasogastric feeding tube, the proportion of affected sisters was even higher, 49/198 (25%). Nine percent of cases reported having at least two affected relatives including sister(s), mother, grandmother, daughters, aunt(s), and cousin(s). There is a high prevalence of severe nausea and vomiting of pregnancy/hyperemesis gravidarum among relatives of hyperemesis gravidarum cases in this study population. Because the incidence of hyperemesis gravidarum is most commonly reported to be 0.5%, this study provides strong but preliminary evidence for a genetic component to extreme nausea and vomiting of pregnancy.

  18. Low hepcidin levels in severely anemic malawian children with high incidence of infectious diseases and bone marrow iron deficiency.

    Directory of Open Access Journals (Sweden)

    Femkje A M Jonker

    Full Text Available A reliable diagnostic biomarker of iron status is required for severely anemic children living in malarious areas because presumptive treatment with iron may increase their infection risk if they are not iron deficient. Current biomarkers are limited because they are altered by host inflammation. In this study hepcidin concentrations were assessed in severely anemic children living in a highly malarious area of Malawi and evaluated against bone marrow iron in order to determine the usefulness of hepcidin as a point of care test.207 severely anemic children were assessed for levels of hepcidin, ferritin, serum transferrin receptor, erythropoietin, hematological indices, C-reactive protein, interleukin-6, malaria parasites and HIV infection. Deficiency of bone marrow iron stores was graded and erythroblast iron incorporation estimated. Interaction of covariates was assessed by structural-equation-modeling.Hepcidin was a poor predictor of bone marrow iron deficiency (sensitivity 66.7%; specificity 48.5%, and of iron incorporation (sensitivity 54.2%; specificity 61.8%, and therefore would have limitations as a point of care test in this category of children. As upregulation of hepcidin by inflammation and iron status was blunted by erythropoietin in this population, enhanced iron absorption through the low hepcidin values may increase infection risk. Current recommendations to treat all severely anemic children living in malarious areas with iron should therefore be reconsidered.

  19. High Prevalence of Severe Food Insecurity and Malnutrition among HIV-Infected Adults in Senegal, West Africa.

    Science.gov (United States)

    Benzekri, Noelle A; Sambou, Jacques; Diaw, Binetou; Sall, El Hadji Ibrahima; Sall, Fatima; Niang, Alassane; Ba, Selly; Ngom Guèye, Ndèye Fatou; Diallo, Mouhamadou Baïla; Hawes, Stephen E; Seydi, Moussa; Gottlieb, Geoffrey S

    2015-01-01

    Malnutrition and food insecurity are associated with increased mortality and poor clinical outcomes among people living with HIV/AIDS; however, the prevalence of malnutrition and food insecurity among people living with HIV/AIDS in Senegal, West Africa is unknown. The objective of this study was to determine the prevalence and severity of food insecurity and malnutrition among HIV-infected adults in Senegal, and to identify associations between food insecurity, malnutrition, and HIV outcomes. We conducted a cross-sectional study at outpatient clinics in Dakar and Ziguinchor, Senegal. Data were collected using participant interviews, anthropometry, the Household Food Insecurity Access Scale, the Individual Dietary Diversity Scale, and chart review. One hundred and nine HIV-1 and/or HIV-2 participants were enrolled. The prevalence of food insecurity was 84.6% in Dakar and 89.5% in Ziguinchor. The prevalence of severe food insecurity was 59.6% in Dakar and 75.4% in Ziguinchor. The prevalence of malnutrition (BMI Malnutrition was associated with lower CD4 cell counts (p = 0.01). Severe food insecurity and malnutrition are highly prevalent among HIV-infected adults in both Dakar and Ziguinchor, and are associated with poor HIV outcomes. Our findings warrant further studies to determine the root causes of malnutrition and food insecurity in Senegal, and the short- and long-term impacts of malnutrition and food insecurity on HIV care. Urgent interventions are needed to address the unacceptably high rates of malnutrition and food insecurity in this population.

  20. Suitability of Secondary PEEK Telescopic Crowns on Zirconia Primary Crowns: The Influence of Fabrication Method and Taper

    Directory of Open Access Journals (Sweden)

    Susanne Merk

    2016-11-01

    Full Text Available This study investigates the retention load (RL between ZrO2 primary crowns and secondary polyetheretherketone (PEEK crowns made by different fabrication methods with three different tapers. Standardized primary ZrO2 crowns were fabricated with three different tapers: 0°, 1°, and 2° (n = 10/group. Ten secondary crowns were fabricated (i milled from breCam BioHPP blanks (PM; (ii pressed from industrially fabricated PEEK pellets (PP (BioHPP Pellet; or (iii pressed from granular PEEK (PG (BioHPP Granulat. One calibrated operator adjusted all crowns. In total, the RL of 90 secondary crowns were measured in pull-off tests at 50 mm/min, and each specimen was tested 20 times. Two- and one-way ANOVAs followed by a Scheffé’s post-hoc test were used for data analysis (p < 0.05. Within crowns with a 0° taper, the PP group showed significantly higher retention load values compared with the other groups. Among the 1° taper, the PM group presented significantly lower retention loads than the PP group. However, the pressing type had no impact on the results. Within the 2° taper, the fabrication method had no influence on the RL. Within the PM group, the 2° taper showed significantly higher retention load compared with the 1° taper. The taper with 0° was in the same range value as the 1° and 2° tapers. No impact of the taper on the retention value was observed between the PP groups. Within the PG groups, the 0° taper presented significantly lower RL than the 1° taper, whereas the 2° taper showed no differences. The fabrication method of the secondary PEEK crowns and taper angles showed no consistent effect within all tested groups.

  1. Correction of severe class II skeletal discrepancy with fixed twin block and high pull headgear--a case report.

    Science.gov (United States)

    Patel, Dolly; Parekh, Harshik; Gupta, Bhaskar; Purl, Taruna

    2014-01-01

    This case report describes the management of a girl with a severe Class II skeletal discrepancy, Class II molar and canine relationship, a large overjet, an impinging overbite and a steep mandibular plane angle. Seemingly a surgical case, but as the patient was in CVMI stage 4, the treatment was initiated with a fixed twin block extending up to the maxillary second molars along with high pull headgear for the vertical control. This promoted the growth of the mandible, restrained maxilla in anteroposterior and vertical directions, combined with the fixed appliances for the aligning and levelling of the dentition improved the soft tissue profile. Thus severe skeletal Class II discrepancy with noncompensatory dental occlusion was successfully managed non-surgically with the combination of dentofacial orthopaedics along with comprehensive orthodontic mechanism without any extraction resulting in acceptable soft tissue changes.

  2. Exploring the Relationship Between Body Mass Index and Positive Symptom Severity in Persons at Clinical High Risk for Psychosis.

    Science.gov (United States)

    Caravaggio, Fernando; Brucato, Gary; Kegeles, Lawrence S; Lehembre-Shiah, Eugénie; Arndt, Leigh Y; Colibazzi, Tiziano; Girgis, Ragy

    2017-11-01

    Metabolic health and positive symptom severity has been investigated in schizophrenia, but not in clinical high risk (CHR) patients. We hypothesized that greater body mass index (BMI) in CHR patients would be related to less positive symptoms. We examined this relationship in CHR patients being treated with 1) no psychotropic medications (n = 58), 2) an antipsychotic (n = 14), or 3) an antidepressant without an antipsychotic (n = 10). We found no relationship between BMI and positive symptoms in unmedicated CHR patients, the majority of whom had a narrow BMI range between 20 and 30. However, in the smaller sample of CHR patients taking an antidepressant or antipsychotic, BMI was negatively correlated with positive symptoms. Although potentially underpowered, these preliminary findings provide initial steps in elucidating the relationships between metabolic health, neurochemistry, and symptom severity in CHR patients.

  3. High intensity positive pressure ventilation and long term pulmonary function responses in severe stable COPD. A delicate and difficult balance.

    Science.gov (United States)

    Esquinas, Antonio M; Petroianni, Angelo

    2014-06-01

    Method to improve minute ventilation (MV) during spontaneous breathing (SB) in stable severe chronic obstructive pulmonary disease (COPD) have a great clinical relevant in long term outcome. In this scenario, recommendations of early use of high-Intensity non-invasive Positive pressure Ventilation (HI-NPPV) or intelligent Volume Assured Pressure (iVAP) Support in Hypercapnic COPD have been proposed by safe therapeutics options. We analyze in this letter, Ekkernkamp et al. study that described the effect of HI-NPPV compared with SB on MV in patients receiving long-term treatment. We consider that interpretation of relationships between ABG, functional parameters, and respiratory mechanics reported need clarifications. Further prospective large clinical trials identifying the best mode of ventilation according to the characteristics in severe stable COPD are necessary to balance an effective approach and response on clinical symptoms and long-term effects.

  4. Fracture load of monolithic CAD/CAM lithium disilicate ceramic crowns and veneered zirconia crowns as a posterior implant restoration.

    Science.gov (United States)

    Kim, Jee Hwan; Lee, Su-Jeong; Park, Jun Sub; Ryu, Jae Jun

    2013-02-01

    To compare the fracture load and failure mode of the monolithic lithium disilicate crown (e.max group) and 2 types of veneered zirconia crowns, hand layer (ZV group) and heat pressed (ZP group), as a posterior implant-supported restoration. A total of 24 all-ceramic crowns for molar tooth were fabricated using the computer-aided design/computer-assisted manufacture (CAD/CAM) system. The e.max group crowns and zirconia copings for ZV and ZP groups were fabricated using a Cerec milling unit. The ZV group was fabricated using a hand-layer veneering method, and the ZP group using a heat-pressing method. All crowns were luted to the abutments, which were connected to implant fixtures, using resin cement. Fracture load was measured using the universal testing machine, and the fracture surface was evaluated by scanning electron microscopy. The ZP group showed significantly higher fracture load (5229.3 N) compared with the e.max group (3852.1 N) and ZV group (3100.3 N). All fractures in the ZV group occurred in the veneered layer. Monolithic CAD/CAM lithium disilicate crowns are applicable to posterior implant-supported restorations because the fracture load was higher than the average occlusal force.

  5. Crown depth as a result of evolutionary games: decreasing solar angle should lead to shallower, not deeper crowns.

    Science.gov (United States)

    Vermeulen, Peter Johannes

    2014-06-01

    There is a general notion in the literature that, with increasing latitude, trees have deeper crowns as a result of a lower solar elevation angle. However, these predictions are based on models that did not include the effects of competition for light between individuals. Here, I argue that there should be selection for trees to increase the height of the crown base, as this decreases shading by neighbouring trees, leading to an evolutionarily stable strategy (ESS). Because the level of between-tree shading increases with decreasing solar angle, the predicted ESS will shift to higher crown base height. This argument is supported by a simulation model to check for the effects of crown shape and the change of light intensity that occurs with changing solar angle on model outcomes. So, the lower solar angle at higher latitudes would tend to select for shallower, and not deeper, crowns. This casts doubt on the common belief that a decreasing solar angle increases crown depth. More importantly, it shows that different assumptions about what should be optimized can lead to different predictions, not just for absolute trait values, but for the direction of selection itself. © 2014 The Author. New Phytologist © 2014 New Phytologist Trust.

  6. Resistance in tomato and wild relatives to crown and root rot caused by Phytophthora capsici.

    Science.gov (United States)

    Quesada-Ocampo, L M; Hausbeck, M K

    2010-06-01

    Phytophthora capsici causes root, crown, and fruit rot of tomato, a major vegetable crop grown worldwide. The objective of this study was to screen tomato cultivars and wild relatives of tomato for resistance to P. capsici. Four P. capsici isolates were individually used to inoculate 6-week-old seedlings (1 g of P. capsici-infested millet seed per 10 g of soilless medium) of 42 tomato cultivars and wild relatives of tomato in a greenhouse. Plants were evaluated daily for wilting and death. All P. capsici isolates tested caused disease in seedlings but some isolates were more pathogenic than others. A wild relative of cultivated tomato, Solanum habrochaites accession LA407, was resistant to all P. capsici isolates tested. Moderate resistance to all isolates was identified in the host genotypes Ha7998, Fla7600, Jolly Elf, and Talladega. P. capsici was frequently recovered from root and crown tissue of symptomatic inoculated seedlings but not from leaf tissue or asymptomatic or control plants. The phenotype of the recovered isolate matched the phenotype of the inoculum. Pathogen presence was confirmed in resistant and moderately resistant tomato genotypes by species-specific polymerase chain reaction of DNA from infected crown and root tissue. Amplified fragment length polymorphisms of tomato genotypes showed a lack of correlation between genetic clusters and susceptibility to P. capsici, indicating that resistance is distributed in several tomato lineages. The results of this study create a baseline for future development of tomato cultivars resistant to P. capsici.

  7. Biological control for grapevine crown gall using nonpathogenic Rhizobium vitis strain ARK-1.

    Science.gov (United States)

    Kawaguchi, Akira; Inoue, Koji; Tanina, Koji; Nita, Mizuho

    2017-01-01

    Crown gall of grapevine, which is caused by tumorigenic Rhizobium vitis, is the most important bacterial disease of grapevine throughout the world. Screening tests of biological control agents resulted in the discovery of a nonpathogenic R. vitis strain ARK-1. By soaking grapevine roots with a cell suspension of strain ARK-1 prior to planting in the field, ARK-1 treatment significantly reduced the number of plants with crown gall symptoms. Several field trials result indicated that ARK-1 was very useful in the field, not only for grapevine but also for various other plant species. In experiments where a mixture of ARK-1 and a tumorigenic strain at a 1 : 1 cell ratio was examined in vitro and in planta, expression levels of the virulence genes virD2 and virE2 of the tumorigenic strain were significantly lower. The suppression of virulence genes, which can result in a reduction of gall formation and the pathogen population, seems to be a unique mechanism of ARK-1. These results indicated that ARK-1 is a promising new agent to control grapevine crown gall.

  8. Genetic variation of major histocompatibility complex genes in the endangered red-crowned crane.

    Science.gov (United States)

    Akiyama, Takuya; Kohyama, Tetsuo I; Nishida, Chizuko; Onuma, Manabu; Momose, Kunikazu; Masuda, Ryuichi

    2017-07-01

    Populations that have drastically decreased in the past often have low genetic variation, which may increase the risk of extinction. The genes of major histocompatibility complex (MHC) play an important role in the adaptive immune response of jawed vertebrates. Maintenance of adaptive genetic diversity such as that of MHC genes is important for wildlife conservation. Here, we determined genotypes of exon 3 of MHC class IA genes (MHCIA) and exon 2 of MHC class IIB genes (MHCIIB) to evaluate genetic variation of the endangered red-crowned crane population on Hokkaido Island, Japan, which experienced severe population decline in the past. We identified 16 and 6 alleles of MHCIA and MHCIIB, respectively, from 152 individuals. We found evidence of a positive selection at the antigen-binding sites in MHCIA exon 3 and MHCIIB exon 2. The phylogenetic analyses indicated evidence of trans-species polymorphism among the crane MHC genes. The genetic variability in both classes of MHC genes at the population level was low. No geographic structure was found based on the genetic diversity of microsatellite and MHC genes. Our study provides useful data for the optimal management of the red-crowned crane population in Hokkaido and can contribute to future studies on MHC genes of the continental populations of the red-crowned crane and other crane species.

  9. Radiolucency below the crown of mandibular horizontal incompletely impacted third molars and acute inflammation in men with diabetes

    Science.gov (United States)

    Yamaoka, Minoru; Ono, Yusuke; Ishizuka, Masahide; Yasuda, Kouichi; Uematsu, Takashi; Furusawa, Kiyofumi

    2009-01-01

    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 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 pericoronitis, whereas the periodontium shows a protective effect against acute pericoronitis. PMID:23674902

  10. High Prevalence of Severe Food Insecurity and Malnutrition among HIV-Infected Adults in Senegal, West Africa.

    Directory of Open Access Journals (Sweden)

    Noelle A Benzekri

    Full Text Available Malnutrition and food insecurity are associated with increased mortality and poor clinical outcomes among people living with HIV/AIDS; however, the prevalence of malnutrition and food insecurity among people living with HIV/AIDS in Senegal, West Africa is unknown. The objective of this study was to determine the prevalence and severity of food insecurity and malnutrition among HIV-infected adults in Senegal, and to identify associations between food insecurity, malnutrition, and HIV outcomes.We conducted a cross-sectional study at outpatient clinics in Dakar and Ziguinchor, Senegal. Data were collected using participant interviews, anthropometry, the Household Food Insecurity Access Scale, the Individual Dietary Diversity Scale, and chart review.One hundred and nine HIV-1 and/or HIV-2 participants were enrolled. The prevalence of food insecurity was 84.6% in Dakar and 89.5% in Ziguinchor. The prevalence of severe food insecurity was 59.6% in Dakar and 75.4% in Ziguinchor. The prevalence of malnutrition (BMI <18.5 was 19.2% in Dakar and 26.3% in Ziguinchor. Severe food insecurity was associated with missing clinic appointments (p = 0.01 and not taking antiretroviral therapy due to hunger (p = 0.02. Malnutrition was associated with lower CD4 cell counts (p = 0.01.Severe food insecurity and malnutrition are highly prevalent among HIV-infected adults in both Dakar and Ziguinchor, and are associated with poor HIV outcomes. Our findings warrant further studies to determine the root causes of malnutrition and food insecurity in Senegal, and the short- and long-term impacts of malnutrition and food insecurity on HIV care. Urgent interventions are needed to address the unacceptably high rates of malnutrition and food insecurity in this population.

  11. High Prevalence of Severe Food Insecurity and Malnutrition among HIV-Infected Adults in Senegal, West Africa

    Science.gov (United States)

    Benzekri, Noelle A.; Sambou, Jacques; Diaw, Binetou; Sall, El Hadji Ibrahima; Sall, Fatima; Niang, Alassane; Ba, Selly; Ngom Guèye, Ndèye Fatou; Diallo, Mouhamadou Baïla; Hawes, Stephen E.; Seydi, Moussa; Gottlieb, Geoffrey S.

    2015-01-01

    Background Malnutrition and food insecurity are associated with increased mortality and poor clinical outcomes among people living with HIV/AIDS; however, the prevalence of malnutrition and food insecurity among people living with HIV/AIDS in Senegal, West Africa is unknown. The objective of this study was to determine the prevalence and severity of food insecurity and malnutrition among HIV-infected adults in Senegal, and to identify associations between food insecurity, malnutrition, and HIV outcomes. Methods We conducted a cross-sectional study at outpatient clinics in Dakar and Ziguinchor, Senegal. Data were collected using participant interviews, anthropometry, the Household Food Insecurity Access Scale, the Individual Dietary Diversity Scale, and chart review. Results One hundred and nine HIV-1 and/or HIV-2 participants were enrolled. The prevalence of food insecurity was 84.6% in Dakar and 89.5% in Ziguinchor. The prevalence of severe food insecurity was 59.6% in Dakar and 75.4% in Ziguinchor. The prevalence of malnutrition (BMI <18.5) was 19.2% in Dakar and 26.3% in Ziguinchor. Severe food insecurity was associated with missing clinic appointments (p = 0.01) and not taking antiretroviral therapy due to hunger (p = 0.02). Malnutrition was associated with lower CD4 cell counts (p = 0.01). Conclusions Severe food insecurity and malnutrition are highly prevalent among HIV-infected adults in both Dakar and Ziguinchor, and are associated with poor HIV outcomes. Our findings warrant further studies to determine the root causes of malnutrition and food insecurity in Senegal, and the short- and long-term impacts of malnutrition and food insecurity on HIV care. Urgent interventions are needed to address the unacceptably high rates of malnutrition and food insecurity in this population. PMID:26529509

  12. High prevalence of leptin and melanocortin-4 receptor gene mutations in children with severe obesity from Pakistani consanguineous families.

    Science.gov (United States)

    Saeed, Sadia; Butt, Taeed A; Anwer, Mehwish; Arslan, Muhammad; Froguel, Philippe

    2012-05-01

    Recessive or co-dominant single-gene mutations disrupting leptin melanocortin pathway cause severe obesity and hyperphagia. Since Pakistan has a very high rate of consanguinity, therefore, a significantly higher incidence of monogenic obesity is expected in its population. We have assessed the incidence of LEP and MC4R mutations and associated hormonal profiles, in a cohort of randomly selected Pakistani children with early onset of severe obesity. Sixty two unrelated children of consanguineous parents, with a weight-for-age percentile >97 were recruited in the study. Screening for mutations in the coding regions of LEP and MC4R was performed by direct sequencing. Serum hormone concentrations were determined by immunoassay. LEP mutations were found in 16.1% of the probands. Of these, 9 probands carried the homozygous frameshift mutation, G133_VfsX14, whereas one patient had a homozygous mutation involving deletion of 3 base pairs, (I35del). In these probands, leptin levels were very low or undetectable and insulin levels were increased in 33%. Homozygous MC4R mutations, M161T and I316S, identified separately in 2 subjects (3.2%), were associated with severe obesity, hyperphagia, hyperleptinemia and hyperinsulinemia. The heterozygous M161T sibling had normal body weight and hormone levels and the parents were only mildly overweight. Based on genetic analysis of LEP and MC4R genes only, we elucidated genetic causality of severe obesity in 20% of our patients confirming high prevalence of monogenic form of obesity in this consanguineous population. Co-dominancy of MC4R is exacerbated in this group with non-penetrance of obesity in heterozygous loss-of-function MC4R mutation carriers. The sub-ethnic specificity of LEP mutation, G133_VfsX14, suggests a founder effect. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Root interactions in a maize/soybean intercropping system control soybean soil-borne disease, red crown rot.

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    Xiang Gao

    Full Text Available BACKGROUND: Within-field multiple crop species intercropping is well documented and used for disease control, but the underlying mechanisms are still unclear. As roots are the primary organ for perceiving signals in the soil from neighboring plants, root behavior may play an important role in soil-borne disease control. PRINCIPAL FINDINGS: In two years of field experiments, maize/soybean intercropping suppressed the occurrence of soybean red crown rot, a severe soil-borne disease caused by Cylindrocladium parasiticum (C. parasiticum. The suppressive effects decreased with increasing distance between intercropped plants under both low P and high P supply, suggesting that root interactions play a significant role independent of nutrient status. Further detailed quantitative studies revealed that the diversity and intensity of root interactions altered the expression of important soybean PR genes, as well as, the activity of corresponding enzymes in both P treatments. Furthermore, 5 phenolic acids were detected in root exudates of maize/soybean intercropped plants. Among these phenolic acids, cinnamic acid was released in significantly greater concentrations when intercropped maize with soybean compared to either crop grown in monoculture, and this spike in cinnamic acid was found dramatically constrain C. parasiticum growth in vitro. CONCLUSIONS: To the best of our knowledge, this study is the first report to demonstrate that intercropping with maize can promote resistance in soybean to red crown rot in a root-dependent manner. This supports the point that intercropping may be an efficient ecological strategy to control soil-borne plant disease and should be incorporated in sustainable agricultural management practices.

  14. Ancestral morphology of crown-group molluscs revealed by a new Ordovician stem aculiferan.

    Science.gov (United States)

    Vinther, Jakob; Parry, Luke; Briggs, Derek E G; Van Roy, Peter

    2017-02-23

    Exceptionally preserved fossils provide crucial insights into extinct body plans and organismal evolution. Molluscs, one of the most disparate animal phyla, radiated rapidly during the early Cambrian period (approximately 535-520 million years ago (Ma)). The problematic fossil taxa Halkieria and Orthrozanclus (grouped in Sachitida) have been assigned variously to stem-group annelids, brachiopods, stem-group molluscs or stem-group aculiferans (Polyplacophora and Aplacophora), but their affinities have remained controversial owing to a lack of preserved diagnostic characters. Here we describe a new early sachitid, Calvapilosa kroegeri gen. et sp. nov. from the Fezouata biota of Morocco (Early Ordovician epoch, around 478 Ma). The new taxon is characterized by the presence of a single large anterior shell plate and polystichous radula bearing a median tooth and several lateral and uncinal teeth in more than 125 rows. Its flattened body is covered by hollow spinose sclerites, and a smooth, ventral girdle flanks an extensive mantle cavity. Phylogenetic analyses resolve C. kroegeri as a stem-group aculiferan together with other single-plated forms such as Maikhanella (Siphogonuchites) and Orthrozanclus; Halkieria is recovered closer to the aculiferan crown. These genera document the stepwise evolution of the aculiferan body plan from forms with a single, almost conchiferan-like shell through two-plated taxa such as Halkieria, to the eight-plated crown-group aculiferans. C. kroegeri therefore provides key evidence concerning the long debate about the crown molluscan affinities of sachitids. This new discovery strongly suggests that the possession of only a single calcareous shell plate and the presence of unmineralised sclerites are plesiomorphic (an ancestral trait) for the molluscan crown.

  15. A graph-based segmentation algorithm for tree crown extraction using airborne LiDAR data

    Science.gov (United States)

    Strîmbu, Victor F.; Strîmbu, Bogdan M.

    2015-06-01

    This work proposes a segmentation method that isolates individual tree crowns using airborne LiDAR data. The proposed approach captures the topological structure of the forest in hierarchical data structures, quantifies topological relationships of tree crown components in a weighted graph, and finally partitions the graph to separate individual tree crowns. This novel bottom-up segmentation strategy is based on several quantifiable cohesion criteria that act as a measure of belief on weather two crown components belong to the same tree. An added flexibility is provided by a set of weights that balance the contribution of each criterion, thus effectively allowing the algorithm to adjust to different forest structures. The LiDAR data used for testing was acquired in Louisiana, inside the Clear Creek Wildlife management area with a RIEGL LMS-Q680i airborne laser scanner. Three 1 ha forest areas of different conditions and increasing complexity were segmented and assessed in terms of an accuracy index (AI) accounting for both omission and commission. The three areas were segmented under optimum parameterization with an AI of 98.98%, 92.25% and 74.75% respectively, revealing the excellent potential of the algorithm. When segmentation parameters are optimized locally using plot references the AI drops to 98.23%, 89.24%, and 68.04% on average with plot sizes of 1000 m2 and 97.68%, 87.78% and 61.1% on average with plot sizes of 500 m2. More than introducing a segmentation algorithm, this paper proposes a powerful framework featuring flexibility to support a series of segmentation methods including some of those recurring in the tree segmentation literature. The segmentation method may extend its applications to any data of topological nature or data that has a topological equivalent.

  16. A comparison of high viscosity bone cement and low viscosity bone cement vertebroplasty for severe osteoporotic vertebral compression fractures.

    Science.gov (United States)

    Zhang, Liang; Wang, Jingcheng; Feng, Xinmin; Tao, Yuping; Yang, Jiandong; Wang, Yongxiang; Zhang, Shengfei; Cai, Jun; Huang, Jijun

    2015-02-01

    To compare the clinical outcome and complications of high viscosity and low viscosity poly-methyl methacrylate bone cement PVP for severe OVCFs. From December 2010 to December 2012, 32 patients with severe OVCFs were randomly assigned to either group H using high viscosity cement (n=14) or group L using low viscosity cement (n=18). The clinical outcomes were assessed by the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), Short Form-36 General Health Survey (SF-36), kyphosis Cobb's angle, vertebral height, and complications. Significant improvement in the VAS, ODI, SF-36 scores, kyphosis Cobb's angle, and vertebral height were noted in both the groups, and there were no significant differences between the two groups. Cement leakage was seen less in group H. Postoperative assessment using computed tomography identified cement leakage in 5 of 17 (29.4%) vertebrae in group H and in 15 of 22 (68.2%) vertebrae in group L (P=0.025). The PVP using high viscosity bone cement can provide the same clinical outcome and fewer complications compared with PVP using low viscosity bone cement. Copyright © 2014. Published by Elsevier B.V.

  17. OH⁻ deficiency in dental enamel, crown and root dentine as studied by ¹H CRAMPS.

    Science.gov (United States)

    Vyalikh, Anastasia; Mai, Ronald; Scheler, Ulrich

    2013-01-01

    High-resolution solid-state NMR based on combined rotation and multipulse spectroscopy (CRAMPS) has been applied to study chemical structures of dental tissues. The samples of human enamel, crown dentine and root dentin studied in this work were used without chemical pre-treatment. The quantitative ¹H NMR spectra permit an assignment to different structures and a quantification of the content of hydroxyl groups. While there is 40% hydroxyl content in the enamel, there is significantly less in the dentin, 14% in the crown and 9% in the root. Thus this study provides the direct evidence of OH⁻ ion deficiency in all dental tissues supporting earlier findings that bone and dental mineral apatite is poorly hydroxylated.

  18. Management of a Complicated Crown Fracture in a Tertiary Care Hospital

    Directory of Open Access Journals (Sweden)

    Md Abdul Hannan Sheikh

    2017-01-01

    Full Text Available Restoration of a fractured tooth is routinely performed in clinical practice. Many factors are considered in an effort to provide optimal mechanical properties, aesthetics, longevity as well as patient acceptance. In this type of challenging endeavour, main effort should be made to save as much of the coronal tooth structure to increase survival rate of endodontically-treated teeth. This case report presents a 35-year-old male with an oblique complicated crown fracture of maxillary left central incisor tooth. The procedure used to repair the fracture was gingivectomy followed by endodontic treatment. The root canal was filled with a root canal sealer and gutta-percha points. After root canal obturation, the tooth was restored with a glass fiber post and composite resin without additional crown coverage. The restoration made it possible to maintain the remaining tooth structure in a good occlusion and resulted in a high level of patient satisfaction.

  19. Calcium isotope fractionation in liquid chromatography with crown ether resin in methanol medium.

    Science.gov (United States)

    Nemoto, Shigeki; Nomura, Masao; Oi, Takao

    2013-06-01

    Breakthrough mode liquid chromatography was employed to investigate calcium (Ca) isotope fractionation in methanol medium. Highly porous silica beads, the inner pores of which were embedded with a benzo-18-crown-6 ether resin, were used as column packing material. Enrichment of heavier isotopes of Ca was observed in the frontal part of the respective Ca chromatograms. The values of the isotope fractionation coefficient (ϵ) were in the order of 10(-3) at 25 °C. Use of methanol as solvent has little advantage over the aqueous system as far as the values of ϵ are concerned. However, a substantial improvement was observed concerning the adsorption capacity of the crown ether resin for Ca ions. Molecular orbital calculations supported the present isotopic results in a qualitative fashion.

  20. Long-term behavior of double crown retained dentures with metal and metal-free secondary crowns and frameworks made of Vectris(©) on all-ceramic primary crowns: a prospective, randomized clinical trial up to 14 years.

    Science.gov (United States)

    Zahn, T; Zahn, B; Janko, S; Weigl, P; Gerhardt-Szép, S; Lauer, H C

    2016-06-01

    This prospective randomized clinical trial aimed to evaluate the long-term behavior of metal-free double crown retained dentures with secondary crowns and dental frameworks made of the fiber-reinforced composite Vectris(©) on all-ceramic primary crowns (IPS Empress 2(©)) over a period of up to 14 years and to subsequently evaluate patient satisfaction. For the control group, electroplated gold copings and metal frameworks were used. A total of 29 patients were treated with a total of 37 prostheses on 165 primary crowns. Of these 37 prostheses, 27 were allotted to the control group and 10 to the test group. The mean observation time was 91 ± 57 months; patient satisfaction surveys were conducted over 77 ± 59 months. Success rates in both groups were compared using Kaplan-Meier survival curves and log-rank test. Up to about 3 years, both types of prostheses exhibited similar success rates. Afterwards, a massive decrease in the Vectris(©) curve could be noted, whereas the metal curve dropped only slightly. This difference was also statistically significant (p = 0.032361). There was a comparable susceptibility to damages in both groups: 88.9 % (control) and 90 % (test), respectively, of the prostheses had to be repaired within the period of investigation (p = 0,121). Damages of the Vectris(©) secondary crowns could be detected significantly more often compared to the electroformed gold copings (p crowns and denture frameworks made with the glass fiber-reinforced composite material Vectris(©) showed a lower survival rate than the electroplated gold copings and metal frameworks. Primary crowns made of IPS Empress 2(©) had insufficient stability. Exclusively high-strength zirconia ceramics should be recommended for this indication. Both clinical and statistical data indicated the superiority of the restorations made with electroplated secondary crowns and metal framework. Therefore, the use of Vectris(©) cannot be recommended for the

  1. Laparoscopic Sleeve Gastrectomy Versus Laparoscopic Adjustable Gastric Banding for the Treatment Severe Obesity in High Risk Patients

    Science.gov (United States)

    2011-01-01

    Background: Laparoscopic sleeve gastrectomy (LSG) has emerged as an alternative restrictive bariatric procedure to the most popular laparoscopic adjustable gastric banding (LAGB). We analyze and compare the clinical and weight loss outcomes of LSG versus LAGB for the treatment of severe obesity in high-risk patients. Methods: Forty severely obese veterans (20/group) received either LSG or LAGB and were followed prospectively for 2 years. Outcome measures included operating room (OR) time, estimated blood loss (EBL), length of hospital stay (LOS), morbidity, mortality, reoperations, readmission rates, and weight loss over time. Results: The cohort primarily comprised high-risk and older male veterans. Patient's baseline demographics were similar between groups. LSG was associated with prolonged OR time (116±31 vs. 94±28min), higher EBL (34±28 vs. 17±19mL), and LOS (2±.9 vs. 1±.4days) when compared with LAGB. Minor morbidity and readmissions were similar between groups, while no major morbidity, reoperations, or mortality occurred. Total weight and BMI decreased significantly after surgery in both groups (LSG: 302±52 to 237lbs and 45±5 to 36±5kg/m2 vs. LAGB: 280±36 to 231±29lbs and 43±5 to 36±5kg/m2, respectively). Total weight loss was superior in the LSG vs. LAGB group at 2 years (TWL=65±24 vs. 49±28 lbs (P=.03); %EWL=51±20 vs. 46±23%; %EBMI loss=48±22 vs. 45±23%, and %BWL = 21±8 vs. 17±9%, respectively). Conclusion: In severely obese and high-risk patients, laparoscopic sleeve gastrectomy provides superior total weight loss at 2 years. PMID:22643503

  2. Transcriptional profiling of Plasmodium falciparum parasites from patients with severe malaria identifies distinct low vs. high parasitemic clusters.

    Science.gov (United States)

    Milner, Danny A; Pochet, Nathalie; Krupka, Malkie; Williams, Chris; Seydel, Karl; Taylor, Terrie E; Van de Peer, Yves; Regev, Aviv; Wirth, Dyann; Daily, Johanna P; Mesirov, Jill P

    2012-01-01

    In the past decade, estimates of malaria infections have dropped from 500 million to 225 million per year; likewise, mortality rates have dropped from 3 million to 791,000 per year. However, approximately 90% of these deaths continue to occur in sub-Saharan Africa, and 85% involve children less than 5 years of age. Malaria mortality in children generally results from one or more of the following clinical syndromes: severe anemia, acidosis, and cerebral malaria. Although much is known about the clinical and pathological manifestations of CM, insights into the biology of the malaria parasite, specifically transcription during this manifestation of severe infection, are lacking. We collected peripheral blood from children meeting the clinical case definition of cerebral malaria from a cohort in Malawi, examined the patients for the presence or absence of malaria retinopathy, and performed whole genome transcriptional profiling for Plasmodium falciparum using a custom designed Affymetrix array. We identified two distinct physiological states that showed highly significant association with the level of parasitemia. We compared both groups of Malawi expression profiles with our previously acquired ex vivo expression profiles of parasites derived from infected patients with mild disease; a large collection of in vitro Plasmodium falciparum life cycle gene expression profiles; and an extensively annotated compendium of expression data from Saccharomyces cerevisiae. The high parasitemia patient group demonstrated a unique biology with elevated expression of Hrd1, a member of endoplasmic reticulum-associated protein degradation system. The presence of a unique high parasitemia state may be indicative of the parasite biology of the clinically recognized hyperparasitemic severe disease syndrome.

  3. Transcriptional profiling of Plasmodium falciparum parasites from patients with severe malaria identifies distinct low vs. high parasitemic clusters.

    Directory of Open Access Journals (Sweden)

    Danny A Milner

    Full Text Available In the past decade, estimates of malaria infections have dropped from 500 million to 225 million per year; likewise, mortality rates have dropped from 3 million to 791,000 per year. However, approximately 90% of these deaths continue to occur in sub-Saharan Africa, and 85% involve children less than 5 years of age. Malaria mortality in children generally results from one or more of the following clinical syndromes: severe anemia, acidosis, and cerebral malaria. Although much is known about the clinical and pathological manifestations of CM, insights into the biology of the malaria parasite, specifically transcription during this manifestation of severe infection, are lacking.We collected peripheral blood from children meeting the clinical case definition of cerebral malaria from a cohort in Malawi, examined the patients for the presence or absence of malaria retinopathy, and performed whole genome transcriptional profiling for Plasmodium falciparum using a custom designed Affymetrix array. We identified two distinct physiological states that showed highly significant association with the level of parasitemia. We compared both groups of Malawi expression profiles with our previously acquired ex vivo expression profiles of parasites derived from infected patients with mild disease; a large collection of in vitro Plasmodium falciparum life cycle gene expression profiles; and an extensively annotated compendium of expression data from Saccharomyces cerevisiae. The high parasitemia patient group demonstrated a unique biology with elevated expression of Hrd1, a member of endoplasmic reticulum-associated protein degradation system.The presence of a unique high parasitemia state may be indicative of the parasite biology of the clinically recognized hyperparasitemic severe disease syndrome.

  4. High-functioning autism patients share similar but more severe impairments in verbal theory of mind than schizophrenia patients.

    Science.gov (United States)

    Tin, L N W; Lui, S S Y; Ho, K K Y; Hung, K S Y; Wang, Y; Yeung, H K H; Wong, T Y; Lam, S M; Chan, R C K; Cheung, E F C

    2017-09-18

    Evidence suggests that autism and schizophrenia share similarities in genetic, neuropsychological and behavioural aspects. Although both disorders are associated with theory of mind (ToM) impairments, a few studies have directly compared ToM between autism patients and schizophrenia patients. This study aimed to investigate to what extent high-functioning autism patients and schizophrenia patients share and differ in ToM performance. Thirty high-functioning autism patients, 30 schizophrenia patients and 30 healthy individuals were recruited. Participants were matched in age, gender and estimated intelligence quotient. The verbal-based Faux Pas Task and the visual-based Yoni Task were utilised to examine first- and higher-order, affective and cognitive ToM. The task/item difficulty of two paradigms was examined using mixed model analyses of variance (ANOVAs). Multiple ANOVAs and mixed model ANOVAs were used to examine group differences in ToM. The Faux Pas Task was more difficult than the Yoni Task. High-functioning autism patients showed more severely impaired verbal-based ToM in the Faux Pas Task, but shared similar visual-based ToM impairments in the Yoni Task with schizophrenia patients. The findings that individuals with high-functioning autism shared similar but more severe impairments in verbal ToM than individuals with schizophrenia support the autism-schizophrenia continuum. The finding that verbal-based but not visual-based ToM was more impaired in high-functioning autism patients than schizophrenia patients could be attributable to the varied task/item difficulty between the two paradigms.

  5. Comparison of incidence of complications and aesthetic performance for posterior metal-free polymer crowns and metal-ceramic crowns: results from a randomized clinical trial.

    Science.gov (United States)

    Ohlmann, Brigitte; Bermejo, Justo Lorenzo; Rammelsberg, Peter; Schmitter, Marc; Zenthöfer, Andreas; Stober, Thomas

    2014-06-01

    The purpose of this randomized clinical study was to evaluate the clinical performance of posterior, metal-free polymer crowns after follow-up for up to six years, and to compare it with the performance of metal-ceramic crowns. Eighty single crowns, manufactured from a polymer composite resin, were set on posterior teeth. Half of these received a glass-fibre framework (group 1) whereas half were prepared without framework stabilization (group 2). As the control group, 40 conventional metal-ceramic crowns were inserted. Primary endpoints were incidence of complications, investigated on a time-to-event basis, plaque status, and aesthetic performance. Thirty clinically relevant complications occurred after a median time of 2.3 years. Median follow-up time was four years. The most frequent complications were delamination (n=24) and root-canal treatment (n=4) of the crowns; the incidence of complications was not significantly different among crown materials (p=0.60). Twenty crowns had to be replaced (six polymer crowns in group 1, nine polymer crowns in group 2, four crowns in the control group, and one tooth (in group 1) had to be extracted). Mean plaque and gingival indexes for the test groups did not differ from those for the control group. Within a median follow-up period of four years, the clinical performance of posterior polymer crowns with and without a glass-fibre framework was not significantly different from that of metal-ceramic crowns, although the number of catastrophic failures of composite crowns was higher than that of the metal-ceramic crowns. On the basis of the study results, posterior polymer crowns may be an alternative to metal-ceramic crowns, although additional research is needed before they can be recommended, without reservation, as permanent restorations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Left Ventricular Apex Venting in High-Risk Redo Sternotomy With Severe Aortic Insufficiency: A Case Report.

    Science.gov (United States)

    Wakefield, Brett J; Leone, Alexander J; Sale, Shiva

    2017-08-10

    Redo cardiac surgery in patients with severe aortic insufficiency can present unique challenges to the anesthesiologist. We report a case highlighting the challenge and importance of interdisciplinary planning between cardiothoracic surgeons and anesthesiologists prior to high-risk surgery. Failure to place an endoaortic balloon and percutaneous coronary sinus catheter due to anatomical abnormalities prompted the adoption of an alternate technique involving apical ventricular venting to assist sternal reentry. Apical left ventricular venting was successfully used to prevent ventricular dilation and dysfunction during institution of cardiopulmonary bypass with significant aortic regurgitation and hypothermia-induced ventricular fibrillation.

  7. Testing of actively cooled mock-ups in several high heat flux facilities-An International Round Robin Test

    Energy Technology Data Exchange (ETDEWEB)

    Roedig, M. [Forschungszentrum Juelich, EURATOM Association, B-NM, D-52425 Juelich (Germany)]. E-mail: m.roedig@fz-juelich.de; Bobin-Vastra, I. [AREVA Centre Technique de Framatome, Porte Magenta, BP181, 71205 Le Creusot Cedex (France); Cox, S. [JET, UKAEA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Escourbiac, F. [CEA-DRFC, Cadarache, 13115 St. Paul lez Durance (France); Gervash, A. [Efremov Institute, St. Petersburg 196641 (Russian Federation); Kapoustina, A. [Forschungszentrum Juelich, EURATOM Association, B-NM, D-52425 Juelich (Germany); Kuehnlein, W. [Forschungszentrum Juelich, EURATOM Association, B-NM, D-52425 Juelich (Germany); Kuznetsov, V. [Efremov Institute, St. Petersburg 196641 (Russian Federation); Merola, M. [EFDA Close Support Unit, Boltzmannstr. 2, D-85748 Garching (Germany); Nygren, R. [Sandia National Laboratories, Albuquerque, NM 87185-1129 (United States); Youchison, D.L. [Sandia National Laboratories, Albuquerque, NM 87185-1129 (United States)

    2005-11-15

    Several electron beam and ion beam facilities are involved in high heat flux testing of plasma-facing components for next step fusion devices. Up to a certain degree, these machines are comparable, but differences concern, e.g. beam generation, beam sweeping, calibration techniques and diagnostics. In order to get an information if tests in the different facilities are really comparable, a set of actively cooled CFC monoblocks has been heated in four electron beam and one ion beam facility at comparable power densities. The temperature response during these loadings has been registered and used as a criteria for assessment.

  8. A comparative study of several compressibility corrections to turbulence models applied to high-speed shear layers

    Science.gov (United States)

    Viegas, John R.; Rubesin, Morris W.

    1991-01-01

    Several recently published compressibility corrections to the standard k-epsilon turbulence model are used with the Navier-Stokes equations to compute the mixing region of a large variety of high speed flows. These corrections, specifically developed to address the weakness of higher order turbulence models to accurately predict the spread rate of compressible free shear flows, are applied to two stream flows of the same gas mixing under a large variety of free stream conditions. Results are presented for two types of flows: unconfined streams with either (1) matched total temperatures and static pressures, or (2) matched static temperatures and pressures, and a confined stream.

  9. Retention of esthetic veneers on primary stainless steel crowns.

    Science.gov (United States)

    Baker, L H; Moon, P; Mourino, A P

    1996-01-01

    The purpose of this study was to ascertain the amount of shearing force necessary to fracture, dislodge or deform the esthetic veneer facings of four commercially available veneered primary incisor stainless steel crowns. The four types tested were: Cheng Crowns, [Peter Cheng Orthodontic Laboratory]; Whiter Biter Crown II, [White Bite Inc.]; Kinder Krowns, [Mayclin Dental Studio, Inc]; and NuSmile Primary Crowns, [Orthodontic Technologies, Inc]. The crowns (#4 right central incisor) from each manufacturer were obtained with the facings attached. The crowns were soaked for ninety days and thermocycled at 4 degrees C and 55 degrees C for 500 45-second cycles. The crowns were cemented to standardized chromium cobalt metal dies. Each die was placed in to a custom holder on the Instron Universal testing machine. A force was applied at the incisal edge of the veneer at 148 degrees, (the primary interincisal angle), with a crosshead speed of 0.05 inches/minute until the veneer either fractured, dislodged or deformed. The mean force (Ibs) required +/- SD to produce failure, in descending order, was as follows: Cheng (107.8 +/- 17.3); NuSmile (100.2 +/- 18.2); KinderKrown (91.3 +/- 27.4)d Whiter Biter (81.5 +/- 21.7). To test the hypothesis of no difference among the four manufacturers, an analysis of variance was performed using PROC GLM. The resultant F statistic was 2.79 (p < 0.0543), indicating a marginally statistically significant difference in the response variable "pressure" among the four groups. A posthoc test was then performed to ascertain where these differences occurred. These results, using Turkey's studentized range test for pairwise comparisons, suggested that the only difference was between the Cheng and Whiter Biter manufacturers.

  10. Environmental and biological cues for spawning in the crown-of-thorns starfish.

    Science.gov (United States)

    Caballes, Ciemon Frank; Pratchett, Morgan S

    2017-01-01

    Sporadic outbreaks of the coral-eating crown-of-thorns starfish are likely to be due, at least in part, to spatial and temporal variation in reproductive and settlement success. For gonochoric and broadcast spawning species such as crown-of-thorns starfish, spawning synchrony is fundamental for achieving high rates of fertilization. Highly synchronized gamete release within and among distinct populations is typically the result of the entrainment of neurohormonal endogenous rhythms by cues from the environment. In this study, we conducted multiple spawning assays to test the effects of temperature change, reduced salinity and nutrient enrichment of seawater, phytoplankton, gametes (sperm and eggs), and the combined effect of sperm and phytoplankton on the likelihood of spawning in male and female crown-of-thorns starfish. We also investigated sex-specific responses to each of these potential spawning cues. We found that (1) abrupt temperature change (an increase of 4°C) induced spawning in males, but less so in females; (2) males often spawned in response to the presence of phytoplankton, but none of the females spawned in response to these cues; (3) the presence of sperm in the water column induced males and females to spawn, although additive and synergistic effects of sperm and phytoplankton were not significant; and (4) males are more sensitive to the spawning cues tested and most likely spawn prior to females. We propose that environmental cues act as spawning 'inducers' by causing the release of hormones (gonad stimulating substance) in sensitive males, while biological cues (pheromones) from released sperm, in turn, act as spawning 'synchronizers' by triggering a hormonal cascade resulting in gamete shedding by conspecifics. Given the immediate temporal linkage between the timing of spawning and fertilization events, variability in the extent and synchronicity of gamete release will significantly influence reproductive success and may account for

  11. Environmental and biological cues for spawning in the crown-of-thorns starfish.

    Directory of Open Access Journals (Sweden)

    Ciemon Frank Caballes

    Full Text Available Sporadic outbreaks of the coral-eating crown-of-thorns starfish are likely to be due, at least in part, to spatial and temporal variation in reproductive and settlement success. For gonochoric and broadcast spawning species such as crown-of-thorns starfish, spawning synchrony is fundamental for achieving high rates of fertilization. Highly synchronized gamete release within and among distinct populations is typically the result of the entrainment of neurohormonal endogenous rhythms by cues from the environment. In this study, we conducted multiple spawning assays to test the effects of temperature change, reduced salinity and nutrient enrichment of seawater, phytoplankton, gametes (sperm and eggs, and the combined effect of sperm and phytoplankton on the likelihood of spawning in male and female crown-of-thorns starfish. We also investigated sex-specific responses to each of these potential spawning cues. We found that (1 abrupt temperature change (an increase of 4°C induced spawning in males, but less so in females; (2 males often spawned in response to the presence of phytoplankton, but none of the females spawned in response to these cues; (3 the presence of sperm in the water column induced males and females to spawn, although additive and synergistic effects of sperm and phytoplankton were not significant; and (4 males are more sensitive to the spawning cues tested and most likely spawn prior to females. We propose that environmental cues act as spawning 'inducers' by causing the release of hormones (gonad stimulating substance in sensitive males, while biological cues (pheromones from released sperm, in turn, act as spawning 'synchronizers' by triggering a hormonal cascade resulting in gamete shedding by conspecifics. Given the immediate temporal linkage between the timing of spawning and fertilization events, variability in the extent and synchronicity of gamete release will significantly influence reproductive success and may account

  12. Evaluation of marginal fit of 2 CAD-CAM anatomic contour zirconia crown systems and lithium disilicate glass-ceramic crown.

    Science.gov (United States)

    Ji, Min-Kyung; Park, Ji-Hee; Park, Sang-Won; Yun, Kwi-Dug; Oh, Gye-Jeong; Lim, Hyun-Pil

    2015-08-01

    This study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns. Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau®Zirconia and ZENOSTAR®ZR translucent) and lithium disilicate glass ceramic (IPS e.max®press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system. The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max®press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) (PCAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR®ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max®press) had overextended margins.

  13. Relationships between problematic Internet use and problem-gambling severity: Findings from a high-school survey

    Science.gov (United States)

    Yau, Yvonne H.C.; Pilver, Corey E.; Steinberg, Marvin A.; Rugle, Loreen J.; Hoff, Rani A.; Krishnan-Sarin, Suchitra; Potenza, Marc N.

    2013-01-01

    With the popularity of Internet use among adolescents, there is concern that some youth may display problematic or addictive patterns of Internet use. Although excessive patterns of Internet use was considered for inclusion in the DSM-5 with pathological gambling and substance-use disorders in a category of addictive disorders, it was determined that more research was needed on Internet-use behaviors before such actions be further considered and possibly undertaken. The present study is the first to investigate whether at-risk/problematic Internet use (ARPIU) may moderate the strength of association between problem-gambling severity and gambling-related characteristics and health and well-being measures in adolescents. Survey data from 1884 Connecticut high-school student stratified by Internet use (ARPIU vs. non-ARPIU) were examined in bivariate analyses and logistic regression models. Gambling-related characteristics and health and well-being measures were mostly positively associated with problem-gambling severity in both Internet use groups. Interaction odds ratio revealed that the strength of the associations between problem-gambling severity and marijuana, alcohol and caffeine use were stronger amongst the non-ARPIU compared to the ARPIU group, suggesting that the relationships between these substance use behaviors and problem gambling may be partially accounted for by ARPIU. Future studies should examine the extent to which preventative interventions targeting both problematic Internet use and problem gambling may synergistically benefit measures of health and reduce risk-taking behaviors in adolescence. PMID:24140304

  14. Severe dermatomyositis with pronounced generalized subcutaneous edema and dysphagia: A rare manifestation of a highly active disease

    Directory of Open Access Journals (Sweden)

    Amy Chia-Ying Peng

    2014-06-01

    Full Text Available Severe subcutaneous edema is rare in dermatomyositis (DM. Such patients usually have a highly active disease, which requires aggressive treatment. To date, there are 14 reported cases of generalized edema secondary to adult DM. We described a severe case of DM manifesting generalized edema, oropharyngeal dysphagia, and dysarthria. A 44-year-old female presented with a typical rash of DM, proximal muscle weakness, and marked swelling of the limbs and face. The findings in the skin biopsy, muscle enzymes, and electromyography were consistent with DM. No internal malignancy was detected. After a brief initial response to oral dexamethasone, the patient experienced a sudden worsening of muscle weakness with dysarthria and an inability to swallow even saliva. A magnetic resonance imaging study revealed edema of the subcutaneous tissue and muscles. The symptoms improved gradually in 2 months after intravenous pulse corticosteroid therapy. Generalized subcutaneous edema is a very rare manifestation of DM that can occur as a presenting symptom. It appears to be a hallmark of a severe DM that requires prompt and aggressive treatment. Additional cases are needed to establish guidelines for treatment of this rare variant.

  15. [Case of occlusal reconstruction for severe attrition].

    Science.gov (United States)

    Ueda, Takayuki

    2006-01-01

    A 57-year-old female complained of aesthetic disturbance, dysmasesis and phonation disorder by attrition. She had severe attrition of almost teeth. To avoid metal color exposure and attrition of opposing teeth, hybrid ceramics were used for veneered crowns and fixed partial denture. Since the prosthetic treatment, the patient wears a night guard to prevent attrition of her teeth and prosthesis. There has been no specific trouble during the 4-year follow-up. It is considered that using hybrid ceramics for veneering crowns and fixed partial denture and night guard help to prevent the attrition of opposing teeth and abrasion of prosthesis.

  16. FULLY AUTOMATED GIS-BASED INDIVIDUAL TREE CROWN DELINEATION BASED ON CURVATURE VALUES FROM A LIDAR DERIVED CANOPY HEIGHT MODEL IN A CONIFEROUS PLANTATION

    Directory of Open Access Journals (Sweden)

    R. J. L. Argamosa

    2016-06-01

    Full Text Available The generation of high resolution canopy height model (CHM from LiDAR makes it possible to delineate individual tree crown by means of a fully-automated method using the CHM’s curvature through its slope. The local maxima are obtained by taking the maximum raster value in a 3 m x 3 m cell. These values are assumed as tree tops and therefore considered as individual trees. Based on the assumptions, thiessen polygons were generated to serve as buffers for the canopy extent. The negative profile curvature is then measured from the slope of the CHM. The results show that the aggregated points from a negative profile curvature raster provide the most realistic crown shape. The absence of field data regarding tree crown dimensions require accurate visual assessment after the appended delineated tree crown polygon was superimposed to the hill shaded CHM.

  17. The effect of oxidative aging on the wear performance of highly crosslinked polyethylene knee inserts under conditions of severe malalignment.

    Science.gov (United States)

    Hermida, Juan C; Fischler, Andrew; Colwell, Clifford W; D'Lima, Darryl D

    2008-12-01

    First-generation crosslinked polyethylene developed for total hip arthroplasty has not gained wide acceptance for knee arthroplasty because of the increased potential for failure under high stresses and the increased risk for oxidative damage caused by free radicals. Sequentially crosslinked polyethylene (SQXL) is a second-generation crosslinked polyethylene that is reported to reduce the level of free radicals and preserve mechanical properties. Three groups of ultrahigh molecular weight polyethylene inserts were wear tested after artificial aging as per ASTM F2003: gamma-irradiated in air (GA-aged), sequentially crosslinked (SQXL-aged), and electron-beam irradiated and remelted (EBeam-aged). Inserts were tested in an AMTI knee wear simulator under malalignment conditions that were two standard deviations from the mean reported for computer-navigated and conventionally aligned techniques. GA-aged inserts delaminated by 500,000 cycles, and were severely damaged after 1 million cycles. None of the highly crosslinked inserts (SQXL-aged or EBeam-aged) delaminated or showed any signs of severe wear. Mean wear rate for GA-aged inserts was 124.6 +/- 49.4 mg/million cycles. Mean wear rates for SQXL-aged and EBeam-aged inserts were significantly lower (1.74 +/- 0.3 and 4.72 +/- 0.7, respectively). These results support the low levels of free radicals and preservation of mechanical properties reported in second-generation crosslinked ultrahigh molecular weight polyethylene.

  18. Tuberculosis caseload in children with severe acute malnutrition related with high hospital based mortality in Lusaka, Zambia.

    Science.gov (United States)

    Munthali, Tendai; Chabala, Chishala; Chama, Elson; Mugode, Raider; Kapata, Nathan; Musonda, Patrick; Michelo, Charles

    2017-06-12

    Tuberculosis and severe acute malnutrition (SAM) in children pose a major treatment and care challenge in high HIV burden countries in Africa. We investigated the prevalence of Tuberculosis notifications among hospitalised under-five children with severe acute malnutrition. A retrospective review of medical records for all children aged 0-59 months admitted to the University Teaching Hospital from 2009 to 2013 was performed. Descriptive statistics were employed to estimate TB caseload. Logistic regression was used to identify predictors of the TB caseload. A total of (n = 9540) under-five children with SAM were admitted over the period reviewed. The median age was 16 months (IQR 11-24) and the proportion diagnosed with TB was 1.58% (95% CI 1.3, 1.8) representing 151 cases. Of these, only 37 (25%) were bacteriologically confirmed cases. The HIV seroprevalence of children with SAM and TB was 46.5%. Children with SAM and TB were 40% more likely to die than children with SAM and without TB. Tuberculosis contributes to mortality among children with SAM in high TB and HIV prevalence settings. The under detection of cases and association of TB with HIV infection in malnutrition opens up opportunities to innovate integrative case finding approaches beyond just HIV counselling and testing within existing mother and child health service areas to include TB screening and prevention interventions, as these are critical primary care elements.

  19. New-born infants with severe hyaline membrane disease: radiological evaluation during high frequency oscillatory versus conventional ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Helbich, T.H.; Wunderbaldinger, P.; Herold, C.J. [Department of Radiology, University of Vienna (AKH), Waehringer Guertel 18-20 A-1090 Vienna (Austria); Popow, C.; Dobner, M.; Zekert, M. [Department of Paediatrics, Division of Neonatology University of Vienna (AKH), Waehringer Guertel 18-20 A-1090 Vienna (Austria)

    1998-10-01

    Objective: The aim of our study was to determine the impact of treatment with exogenous surfactant (ES) and high frequency oscillatory ventilation (HFOV) on the radiological appearance and clinical course of hyaline membrane disease (HMD) in new-born infants. Materials and methods: New-born infants (18) (median weight, 1010 g) with severe HMD (stages 3.5 and 4) who were treated with ES and HFOV were matched by birth weight and severity of disease with 18 new-born infants treated with ES and conventional mechanical ventilation (CV). Chest radiograms taken on days 1, 2/3, 4/5, 7, 14 and 28 were analyzed to check for the severity of generalized parenchymal opacities (GPO), local opacifications, pulmonary interstitial emphysema (PIE), gross air leak, general and localized overinflation, bronchopulmonary dysplasia (BPD) and clinical variables such as survival rates, duration of mechanical ventilation, mean airway pressure and inspired oxygen concentration. Results: At 4 weeks of age, new-born infants treated by HFOV had less severe GPO (median degree 1.5 vs. 3), less PIE (1 vs. 7 patients) and fewer signs of BPD (median BPD degree 1.5 vs. 2.6). The incidence of pneumothorax and of local opacifications were similar in both groups. New-born infants on HFOV had a lower mortality rate (5 vs. 13), needed fewer days of mechanical ventilation (median 15 vs. 23 days) and lower inspiratory oxygen concentrations (median FiO{sub 2} 0.38 vs. 0.64). Conclusion: In new-born infants with HMD, treatment with ES and HFOV resulted in a favourable radiological and clinical outcome as compared to treatment with ES and CV. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  20. Long-term administration of high doses of transdermal buprenorphine in cancer patients with severe neuropathic pain

    Directory of Open Access Journals (Sweden)

    Leppert W

    2015-12-01

    Full Text Available Wojciech Leppert, Grzegorz Kowalski Chair and Department of Palliative Medicine, Poznan University of Medical Sciences, Poznan, Poland Background: Buprenorphine is often administered by the transdermal route (transdermal buprenorphine [TB] in cancer patients with severe neuropathic pain. However, high doses of TB of 140 µg/h are rarely used.Patients and methods: Three cancer patients with severe neuropathic Numeric Rating Scale (NRS pain scores of 8–10 who were successfully treated with high doses of TB up to 140 µg/h along with other opioids and adjuvant analgesics.Results: TB was administered for a long period of follow-up (9 months to 4 years, including 34–261 days of treatment with the dose of 140 µg/h, which allowed achievement of satisfactory analgesia (NRS 3–5 and good treatment tolerance. In all three patients, TB dose was gradually titrated from 35 to 140 µg/h, and all patients used morphine at least for some time for breakthrough and background pain management along with adjuvant analgesics. Two patients continued the treatment with TB until the end of life, and one patient is still receiving the treatment.Conclusion: TB at doses of up to 140 µg/h in cancer patients with severe neuropathic pain seems to be effective and safe in combination with other opioids and with adjuvant analgesics, and may significantly improve patients’ quality of life. Clinical studies may explore higher than maximal 140 µg/h TB doses recommended by a manufacturer, and also in combination with other opioids and adjuvant analgesics. Keywords: adverse effects, analgesia, cancer, neuropathic pain, transdermal buprenorphine, treatment

  1. Synthesis of poly(arylene ether ketone)s bearing skeletal crown ether units for cation exchange membranes

    NARCIS (Netherlands)

    Zoetebier, Bram; Tas, Sinem; Vancso, Gyula J.; Nijmeijer, Dorothea C.; Hempenius, Mark A.

    2015-01-01

    Poly(arylene ether ketone)s (PAEKs) are the most commonly known high-performance materials used for ion exchange and fuel cell membranes. Described here is the design of novel sulfonated PAEKs (SPAEKs) and nonsulfonated PAEKs containing crown ether units in the main chain, which can be used in

  2. Effect of the crown preparation margin and die type on the marginal accuracy of fiber-reinforced composite crowns.

    Science.gov (United States)

    Ayad, Mohamed F

    2008-02-01

    The objective of this laboratory investigation was to determine the effect of different preparation designs (light chamfer, deep chamfer, and shoulder) and die-making materials (stone and epoxy) on the resulting margin misfit for fiber-reinforced composite crowns using a measuring microscope. Sixty standardized FibreKor crowns were made on stone and epoxy resin dies (n=30 each) duplicated from three metal master dies representing complete crown tooth preparation with a total convergence of 5 degrees . For each die group, three of the tooth preparation designs were established in relation to the type of finish line (n=0 each) as follows: Group A (0.5-mm light chamfer finish line); Group B (1.0-mm deep chamfer finish line); and Group C (1.0-mm shoulder finish line). Marginal accuracy was evaluated by measuring the distances between each of four pairs of indentations on the crowns and on the dies with a Nikon measuring microscope. Analysis of seating measurements with parametric analysis of variance and Tukey's Studentized Range (HSD) disclosed a statistically significant difference for both tooth preparation design and die material (pcrowns made on epoxy resin dies with a light chamfer finish line (57 microm), but the difference was not statistically significantly different from crowns made on epoxy resin dies with a deep chamfer light chamfer finish line (61 microm). However, crowns made on epoxy resin dies with a shoulder finish line (81 microm) had significantly higher values (pcrowns made on stone dies with the shoulder finish line (95 microm) had statistically higher marginal opening values (pcrowns made on stone dies with a light chamfer finish line (66 microm), but the difference was not statistically significantly different from crowns made on stone dies with a deep chamfer light chamfer finish line (70 microm). Significant differences were found among the die material used for the shoulder margin design. However, there was no significant difference between

  3. The use of stainless steel crowns: a systematic literature review.

    Science.gov (United States)

    Seale, N Sue; Randall, Ros

    2015-01-01

    The purpose was to review the published literature on stainless steel crowns (SSCs) from 2002 to the present as an update to an earlier review published in 2002. Included were published papers on clinical studies, case series, and laboratory testing on SSCs (including esthetic SSCs and the Hall technique) in peer-reviewed journals. Study quality and strength of evidence presented were assessed for papers reporting clinical results for SSCs as a primary study outcome using a list of weighting criteria. Sixty-one papers fulfilled the inclusion criteria (24 papers on 22 clinical studies, three case reports, 21 reviews and surveys, and 13 laboratory testing reports on SSCs and esthetic preformed metal crowns for primary and permanent molar teeth). Ten clinical studies achieved weighting scores ranging from 68 percent to 26 percent, with the two highest scoring studies (68 percent and 63 percent) considered good quality. Within the confines of the studies reviewed, primary molar esthetic crowns and SSCs had superior clinical performance as restoratives for posterior primary teeth, and the Hall technique was shown to have validity. No clinical studies were available on zirconia crowns. Further well-designed prospective studies on primary molar esthetic crowns and the Hall technique are needed.

  4. Wind Tunnel Experiments to Study Chaparral Crown Fires.

    Science.gov (United States)

    Cobian-Iñiguez, Jeanette; Aminfar, AmirHessam; Chong, Joey; Burke, Gloria; Zuniga, Albertina; Weise, David R; Princevac, Marko

    2017-11-14

    The present protocol presents a laboratory technique designed to study chaparral crown fire ignition and spread. Experiments were conducted in a low velocity fire wind tunnel where two distinct layers of fuel were constructed to represent surface and crown fuels in chaparral. Chamise, a common chaparral shrub, comprised the live crown layer. The dead fuel surface layer was constructed with excelsior (shredded wood). We developed a methodology to measure mass loss, temperature, and flame height for both fuel layers. Thermocouples placed in each layer estimated temperature. A video camera captured the visible flame. Post-processing of digital imagery yielded flame characteristics including height and flame tilt. A custom crown mass loss instrument developed in-house measured the evolution of the mass of the crown layer during the burn. Mass loss and temperature trends obtained using the technique matched theory and other empirical studies. In this study, we present detailed experimental procedures and information about the instrumentation used. The representative results for the fuel mass loss rate and temperature filed within the fuel bed are also included and discussed.

  5. Effect of cements on fracture resistance of monolithic zirconia crowns

    Science.gov (United States)

    Nakamura, Keisuke; Mouhat, Mathieu; Nergård, John Magnus; Lægreid, Solveig Jenssen; Kanno, Taro; Milleding, Percy; Örtengren, Ulf

    2016-01-01

    Abstract Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical cure mode (RC-C). First, the compressive strength of each cement was tested according to a standard (ISO 9917-1:2004). Second, load-to-failure test was performed to analyze the crown fracture resistance. CAD/CAM-produced monolithic zirconia crowns with a minimal thickness of 0.5 mm were prepared and cemented to dies with each cement. The crown–die samples were loaded until fracture. Results The compressive strength of SRC, RC-D and RC-C was significantly higher than those of ZPC and GIC (p crown between the groups. Conclusion The values achieved in the load-to-failure test suggest that monolithic zirconia crowns with a minimal thickness of 0.5 mm may have good resistance against fracture regardless of types of cements. PMID:27335900

  6. Brochopulmonary dysplasia: New high resolution computed tomography scorting system and correlation between the high resolution computed tomography score and clinical severity

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sumi; Kim, Woo Sun; Cheon, Jung Eun; Kim, Han Suk; Lee, Whal; Jung, Ah Young; Kim, In One; Choi, Jung Hwan [Seoul National University College of Medicine, Seoul (KR)

    2013-04-15

    To develop an high resolution computed tomography (HRCT) scoring system for the assessment of bronchopulmonary dysplasia (BPD) and determine its usefulness as compared with the chest radiographic score. Forty-two very low-birth-weight preterm infants with BPD (25 male, 17 female) were prospectively evaluated with HRCT performed at the mean age of 39.1-week postmenstrual age. Clinical severity of BPD was categorized as mild, moderate or severe. The HRCT score (0-36) of each patient was the sum of the number of bronchopulmonary segments with 1) hyperaeration and 2) parenchymal lesions (linear lesions, segmental atelectasis, consolidation and architectural distortion), respectively. We compared the HRCT scores with the chest radiographic scores (the Toce system) in terms of correlation with clinical severity. The HRCT score had good interobserver (r = 0.969, p < 0.001) and intraobserver (r = 0.986, p < 0.001) reproducibility. The HRCT score showed better correlation (r = 0.646, p < 0.001) with the clinical severity of BPD than the chest radiographic score (r = 0.410, p = 0.007). The hyperaeration score showed better correlation (r = 0.738, p < 0.001) with the clinical severity of BPD than the parenchymal score (r = 0.523, p < 0.001). We have developed a new HRCT scoring system for BPD based on the quantitative evaluation of pulmonary abnormalities of BPD consisting of the hyperaeration score and the parenchymal score. The HRCT score shows better correlation with the clinical severity of BPD than the radiographic score.

  7. Characteristics of highly impaired children with severe chronic pain: a 5-year retrospective study on 2249 pediatric pain patients

    Directory of Open Access Journals (Sweden)

    Zernikow Boris

    2012-05-01

    Full Text Available Abstract Background Prevalence of pain as a recurrent symptom in children is known to be high, but little is known about children with high impairment from chronic pain seeking specialized treatment. The purpose of this study was the precise description of children with high impairment from chronic pain referred to the German Paediatric Pain Centre over a 5-year period. Methods Demographic variables, pain characteristics and psychometric measures were assessed at the first evaluation. Subgroup analysis for sex, age and pain location was conducted and multivariate logistic regression applied to identify parameters associated with extremely high impairment. Results The retrospective study consisted of 2249 children assessed at the first evaluation. Tension type headache (48%, migraine (43% and functional abdominal pain (11% were the most common diagnoses with a high rate of co-occurrence; 18% had some form of musculoskeletal pain disease. Irrespective of pain location, chronic pain disorder with somatic and psychological factors was diagnosed frequently (43%. 55% of the children suffered from more than one distinct pain diagnosis. Clinically significant depression and general anxiety scores were expressed by 24% and 19% of the patients, respectively. Girls over the age of 13 were more likely to seek tertiary treatment compared to boys. Nearly half of children suffered from daily or constant pain with a mean pain value of 6/10. Extremely high pain-related impairment, operationalized as a comprehensive measure of pain duration, frequency, intensity, pain-related school absence and disability, was associated with older age, multiple locations of pain, increased depression and prior hospital stays. 43% of the children taking analgesics had no indication for pharmacological treatment. Conclusion Children with chronic pain are a diagnostic and therapeutic challenge as they often have two or more different pain diagnoses, are prone to misuse of

  8. Explicit area-based accuracy assessment for mangrove tree crown delineation using Geographic Object-Based Image Analysis (GEOBIA)

    Science.gov (United States)

    Kamal, Muhammad; Johansen, Kasper

    2017-10-01

    Effective mangrove management requires spatially explicit information of mangrove tree crown map as a basis for ecosystem diversity study and health assessment. Accuracy assessment is an integral part of any mapping activities to measure the effectiveness of the classification approach. In geographic object-based image analysis (GEOBIA) the assessment of the geometric accuracy (shape, symmetry and location) of the created image objects from image segmentation is required. In this study we used an explicit area-based accuracy assessment to measure the degree of similarity between the results of the classification and reference data from different aspects, including overall quality (OQ), user's accuracy (UA), producer's accuracy (PA) and overall accuracy (OA). We developed a rule set to delineate the mangrove tree crown using WorldView-2 pan-sharpened image. The reference map was obtained by visual delineation of the mangrove tree crowns boundaries form a very high-spatial resolution aerial photograph (7.5cm pixel size). Ten random points with a 10 m radius circular buffer were created to calculate the area-based accuracy assessment. The resulting circular polygons were used to clip both the classified image objects and reference map for area comparisons. In this case, the area-based accuracy assessment resulted 64% and 68% for the OQ and OA, respectively. The overall quality of the calculation results shows the class-related area accuracy; which is the area of correctly classified as tree crowns was 64% out of the total area of tree crowns. On the other hand, the overall accuracy of 68% was calculated as the percentage of all correctly classified classes (tree crowns and canopy gaps) in comparison to the total class area (an entire image). Overall, the area-based accuracy assessment was simple to implement and easy to interpret. It also shows explicitly the omission and commission error variations of object boundary delineation with colour coded polygons.

  9. Investigation of distortions around the cervical area of teeth restored with two kinds of crown materials.

    Science.gov (United States)

    Suzuki, Chikako; Miura, Hiroyuki; Okada, Daizo; Komada, Wataru; Miyasaka, Munenaga; Yamamoto, Masahiro; Masuoka, David

    2009-03-01

    The purpose of this study was to identify crown materials to decrease the stress concentrated at the cervical area of endodontically treated teeth. To this end, 14 extracted human mandibular premolars were divided into two groups for this study: complete cast crowns versus polymer-based crown and bridge material crowns. Both complete cast crowns (MC) and polymer-based crown and bridge material crowns (HC) were cemented with a glycidyl methacrylate-based resin cement (RC) to composite resin cores with glass fiber posts. Static loading was applied and distortion was measured with four pieces of strain gages attached to the marginal area. Findings showed that there was a large difference in distortion between crown and root in MC. On the other hand, distortions at the cervical area of crown and root were similar in HC.

  10. Fracture Strength After Fatigue Loading of Lithium Disilicate Pressed Zirconia Crowns.

    Science.gov (United States)

    Kim, So-Yeun; Choi, Jae-Won; Ju, Sung-Won; Ahn, Jin-Soo; Yoon, Mi-Jung; Huh, Jung-Bo

    2016-01-01

    The aim of this study was to evaluate the fracture resistance of fatigued lithium disilicate pressed zirconia crowns versus other ceramic crowns. Lithium disilicate pressed zirconia, fluorapatite pressed zirconia, monolithic lithium disilicate, and monolithic zirconia crowns were fabricated. Cyclic and static loadings were applied to the mesiobuccal cusp tip after thermocycling and fracture strengths were recorded. Fatigued lithium disilicate pressed zirconia crowns were found to have a fracture resistance of 9,117.81 ± 727.04 N, compared with 9,240.61 ± 887.21 N for monolithic zirconia crowns, 3,030.18 ± 1,505.83 N for fluorapatite pressed zirconia crowns, and 4,173.94 ± 877.46 N for monolithic lithium disilicate crowns (P = .001). This in vitro study shows that fatigued lithium disilicate pressed zirconia and monolithic zirconia crowns have better fracture resistance than fluorapatite pressed zirconia and monolithic lithium disilicate crowns.

  11. Double crown-retained maxillary overdentures: 5-year follow-up.

    Science.gov (United States)

    Frisch, Eberhard; Ziebolz, Dirk; Ratka-Krüger, Petra; Rinke, Sven

    2015-02-01

    There is a lack of data concerning implant-supported overdentures (IODs) retained by double crowns in the edentulous maxilla. To perform a retrospective evaluation of clinical outcomes (survival/success rates) of maxillary overdentures retained on four implants via double crowns. Between 1993 and 2011, 28 patients with edentulous maxillae were restored with overdentures supported by four implants with a Morse taper connection (Ankylos, Dentsply Friadent, Mannheim, Germany) and double crowns according to the Marburg Double Crown (MDC) technique in a private practice. For retrospective evaluation of implant and prosthetic survival (in situ criterion) and success (event-free observational period), only patients attending a professional maintenance program were included (n = 20). Twenty patients (13 female/ seven male, mean age: 63.45 ± 7.18 years) with 80 implants met the inclusion criteria. The mean follow-up period was 5.64 ± 3.50 years. One implant was lost (cumulative survival rate: 98.75%). Eight implants (10.1%) in two patients (10%) showed peri-implantitis; both patients were active smokers (cumulative success rate: 88.75%). All dentures were still functional (prosthetic survival rate 100%) at the time of investigation. Technical maintenance procedures (e.g., abutment loosening, screw loosening, acrylic fracture or relining) were required at a rate of 0.222/patient-year. Within the limitations of this study, we conclude that MDC-IODs are a promising treatment alternative for edentulous maxillae offering high implant and prosthesis survival rates > 98% and a limited incidence of biological and technical complications after a mean observational period of >5 years. © 2013 Wiley Periodicals, Inc.

  12. Results of crown-height reduction and partial coronal pulpectomy in rhesus monkeys (Macaca mulatta).

    Science.gov (United States)

    Lommer, M J; Verstraete, F J

    2001-02-01

    In research facilities using non-human primates, crown-height reduction with partial coronal pulpectomy ("vital pulpotomy") is routinely performed on canine teeth of adult male monkeys to reduce self-trauma and the potential for injury to staff or cage-mates. Success of pulpotomy techniques in humans is reportedly 40 to 60%. Failure leads to chronic inflammation and pulp necrosis, which introduces variability in research animals, and may affect research results. The purpose of the study reported here was to determine failure rate of this procedure by evaluating clinical and radiographic findings at 3, 9, and 24 months after crown amputation and partial coronal pulpectomy of maxillary canines in adult male rhesus monkeys. Forty-seven maxillary canine teeth from 24 adult male rhesus monkeys were treated by use of crown amputation and partial coronal pulpectomy, using standard dental technique. Follow-up clinical and radiographic examination was performed 3, 9, and 24 months after surgery. At three months after surgery, there was no clinical evidence of failure at any of the teeth. On the basis of radiographic findings, 2 of 47 teeth had failed and one was suspicious for early failure. At nine months, clinical evidence of failure was not apparent; radiographically, 5 of 44 teeth appeared to have failed and 3 others were suspect. Two years post-operatively, failure was clinically evident at two teeth, with radiographic evidence of failure in five teeth, and suspicion of early failure in an additional six of 41 teeth [corrected]. The failure rate of crown amputation and partial coronal pulpectomy of canine teeth in adult male rhesus monkeys is high, and the chronic inflammation associated with this is cause for concern.

  13. Characterization of the Migration of Hop Volatiles into Different Crown Cork Liner Polymers and Can Coatings.

    Science.gov (United States)

    Wietstock, Philip C; Glattfelder, Richard; Garbe, Leif-Alexander; Methner, Frank-Jürgen

    2016-04-06

    Absorption of hop volatiles by crown cork liner polymers and can coatings was investigated in beer during storage. All hop volatiles measured were prone to migrate into the closures, and the absorption kinetics was demonstrated to fit Fick's second law of diffusion well for a plane sheet. The extent and rate of diffusion were significantly dissimilar and were greatly dependent upon the nature of the volatile. Diffusion coefficients ranged from 1.32 × 10(-5) cm(2)/day (limonene) to 0.26 × 10(-5) cm(2)/day (α-humulene). The maximum amounts absorbed into the material at equilibrium were in the following order: limonene > α-humulene > trans-caryophyllene > myrcene ≫ linalool > α-terpineol > geraniol. With the application of low-density polyethylene (LDPE) liners with oxygen-scavenging functionality, oxygen-barrier liners made up from high-density polyethylene (HDPE) or liner polymers from a different manufacturer had no significant effect on the composition of hop volatiles in beers after prolonged storage of 55 days; however, significantly higher amounts of myrcene and limonene were found in the oxygen-barrier-type crown cork, while all other closures behaved similarly. Can coatings were demonstrated to absorb hop volatiles in a similar pattern as crown corks but to a lesser extent. Consequently, significantly higher percentages of myrcene were found in the beers.

  14. Clinical study on the success of posterior monolithic zirconia crowns and fixed dental prostheses: preliminary report

    Directory of Open Access Journals (Sweden)

    Merve Bankoğlu Güngör

    2017-09-01

    Full Text Available Objective: The purpose of this report was to present preliminary clinical results regarding the success rates and technical outcomes of posterior monolithic zirconia single tooth crowns (STs and fixed dental prostheses (FDPs. Materials and Method: Thirty-four patients received 43 posterior monolithic zirconia restorations as single tooth crowns (STs and/or fixed dental prostheses (FDPs, which were fabricated using a CAD-CAM (Computer Aided Design - Computer Aided Manufacturing system. At baseline and every 6 months, the restorations were examined for survival and technical outcomes. Success of the restorations was defined as the restoration remaining in situ, with no need for removal or replacement at follow-up visits. Technical outcomes were evaluated with a modified version of the United States Public Health Services criteria. Survival of restorations was estimated by using the Kaplan-Meier survival analysis. For each restoration, duration of follow-up was calculated from the time of placement to the date of its first failure. Results: After a mean observation period of 18.6 ± 3.9 months (between 8-24 months, cumulative survival rates were 86.7% and 92.3% for STs and FDPs, respectively. Technical evaluation revealed good marginal adaptation and crown contours; however, modifications were needed for shade and occlusion of restorations. Conclusion: These preliminary results revealed high survival rate and generally successful technical outcomes for posterior monolithic zirconia STs and FDPs.

  15. On the Formation Mechanism of A Long-lived Polar Crown Cavity

    Science.gov (United States)

    Karna, Nishu; Pesnell, William D.; Zhang, Jie

    2016-10-01

    We report the study of the longest-lived polar crown cavity of Solar Cycle 24th observed in the year 2013 and propose a physical mechanism to explain the sustained existence. We used high temporal and spatial resolution observations from the Atmospheric Imaging Assembly (AIA) and the Helioseismic Magnetic Imager (HMI) instruments on board the Solar Dynamics Observatory (SDO) to explore the structure and evolution. We examined the circumpolar cavity in great detail from March 21, 2013, till October 31, 2013, while it existed for more than one year. Our study suggests two necessary conditions to form a long stable circumpolar cavity or any polar crown cavity. First, the underlying polarity inversion line (PIL) of the circumpolar cavity is formed between the trailing part of dozens of decayed active regions distributed in different longitudes and the unipolar magnetic field in the polar coronal hole. Second, the long life of the cavity is sustained by the continuing flux cancellation along the polarity inversion line. The flux is persistently transported toward the polar region through surface meridional flow and diffusion, which also leads to the shrinking of the polar coronal hole. Comparing with the existing theory of the formation of polarity inversion lines, we introduce a new category named as "Diffused trailing flux and polar coronal hole interaction region" to explain the polar crown cavity. The existence of such region also helps explain the process of polar reversal, which provides insight into the solar cycle.

  16. Did enhanced afforestation cause high severity peat burn in the Fort McMurray Horse River wildfire?

    Science.gov (United States)

    Wilkinson, S. L.; Moore, P. A.; Flannigan, M. D.; Wotton, B. M.; Waddington, J. M.

    2018-01-01

    Climate change mediated drying of boreal peatlands is expected to enhance peatland afforestation and wildfire vulnerability. The water table depth–afforestation feedback represents a positive feedback that can enhance peat drying and consolidation and thereby increase peat burn severity; exacerbating the challenges and costs of wildfire suppression efforts and potentially shifting the peatland to a persistent source of atmospheric carbon. To address this wildfire management challenge, we examined burn severity across a gradient of drying in a black spruce dominated peatland that was partially drained in 1975‑1980 and burned in the 2016 Fort McMurray Horse River wildfire. We found that post-drainage black spruce annual ring width increased substantially with intense drainage. Average (±SD) basal diameter was 2.6 ± 1.2 cm, 3.2 ± 2.0 cm and 7.9 ± 4.7 cm in undrained (UD), moderately drained (MD) and heavily drained (HD) treatments, respectively. Depth of burn was significantly different between treatments (p < 0.001) and averaged (±SD) 2.5 ± 3.5 cm, 6.4 ± 5.0 cm and 36.9 ± 29.6 cm for the UD, MD and HD treatments, respectively. The high burn severity in the HD treatment included 38% of the treatment that experienced combustion of the entire peat profile, and we estimate that overall 51% of the HD pre-burn peat carbon stock was lost. We argue that the HD treatment surpassed an ecohydrological tipping point to high severity peat burn that may be identified using black spruce stand characteristics in boreal plains bogs. While further studies are needed, we believe that quantifying this threshold will aid in developing effective adaptive management techniques and protecting boreal peatland carbon stocks.

  17. Benthic Predators Influence Microhabitat Preferences and Settlement Success of Crown-of-Thorns Starfish (Acanthaster cf. solaris

    Directory of Open Access Journals (Sweden)

    Zara-Louise Cowan

    2016-12-01

    Full Text Available Like most coral reef organisms, crown-of-thorns starfish (Acanthaster spp. are expected to be highly vulnerable to predation as they transition from a planktonic larval phase to settling among reef habitats. Accordingly, crown-of-thorns starfish might be expected to exhibit behavioural adaptations which moderate exposure to predation at this critical stage in their life history. Using pairwise choice experiments and settlement assays, we explored the ability of competent larvae of Acanthaster cf. solaris to first detect and then actively avoid benthic predators during settlement. Pairwise choice experiments revealed that late stage brachiolaria larvae are able to detect predators in the substrate and where possible, will preferentially settle in microhabitats without predators. Settlement assays (without choices revealed that larvae do not necessarily delay settlement in the presence of predators, but high levels of predation on settling larvae by benthic predators significantly reduce the number of larvae that settle successfully. Taken together, these results show that crown-of-thorns starfish are highly vulnerable to benthic predators during settlement, and that variation in the abundance of benthic predators may exert a significant influence on patterns of settlement for crown-of-thorns starfish.

  18. Reduction of HCCI combustion noise through piston crown design

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper

    2010-01-01

    Seven shapes of piston crowns have been evaluated for their ability to reduce HCCI knock and transmission of combustion noise to the engine. The performance of each piston crown was evaluated with measurements of cylinder pressure, engine vibration and acoustic sound pressure measured one meter......, increased heat transfer can not be avoided. Thus, the use of alternative piston crown geometries designed to split the combustion may not be viable means of avoiding HCCI engine knock. The traditional diesel bowl type piston is therefore possibly the best alternative to the flat piston in terms of noise...... away from the engine. The experiments were conducted in a diesel engine that was run in HCCI combustion mode with a fixed quantity of DME as fuel. The results show that combustion knock is effectively suppressed by limiting the size of the volume in which the combustion occurs. Splitting...

  19. [Study on the compatibility of slip casting aluminous ceramic crowns