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Sample records for assessing double acid-etched

  1. Effects of dextrose and lipopolysaccharide on the corrosion behavior of a Ti-6Al-4V alloy with a smooth surface or treated with double-acid-etching.

    PubMed

    Faverani, Leonardo P; Assunção, Wirley G; de Carvalho, Paulo Sérgio P; Yuan, Judy Chia-Chun; Sukotjo, Cortino; Mathew, Mathew T; Barao, Valentim A

    2014-01-01

    Diabetes and infections are associated with a high risk of implant failure. However, the effects of such conditions on the electrochemical stability of titanium materials remain unclear. This study evaluated the corrosion behavior of a Ti-6Al-4V alloy, with a smooth surface or conditioned by double-acid-etching, in simulated body fluid with different concentrations of dextrose and lipopolysaccharide. For the electrochemical assay, the open-circuit-potential, electrochemical impedance spectroscopy, and potentiodynamic test were used. The disc surfaces were characterized by scanning electron microscopy and atomic force microscopy. Their surface roughness and Vickers microhardness were also tested. The quantitative data were analyzed by Pearson's correlation and independent t-tests (α = 0.05). In the corrosion parameters, there was a strong lipopolysaccharide correlation with the Ipass (passivation current density), Cdl (double-layer capacitance), and Rp (polarization resistance) values (p<0.05) for the Ti-6Al-4V alloy with surface treatment by double-acid-etching. The combination of dextrose and lipopolysaccharide was correlated with the Icorr (corrosion current density) and Ipass (p<0.05). The acid-treated groups showed a significant increase in Cdl values and reduced Rp values (p<0.05, t-test). According to the topography, there was an increase in surface roughness (R2 = 0.726, p<0.0001 for the smooth surface; R2 = 0.405, p = 0.036 for the double-acid-etching-treated surface). The microhardness of the smooth Ti-6Al-4V alloy decreased (p<0.05) and that of the treated Ti-6Al-4V alloy increased (p<0.0001). Atomic force microscopy showed changes in the microstructure of the Ti-6Al-4V alloy by increasing the surface thickness mainly in the group associated with dextrose and lipopolysaccharide. The combination of dextrose and lipopolysaccharide affected the corrosion behavior of the Ti-6Al-4V alloy surface treated with double-acid-etching. However, no

  2. Fabrication, characterization, and biological assessment of multilayer DNA coatings on sandblasted-dual acid etched titanium surface.

    PubMed

    Liu, Li; Song, Li-Na; Yang, Guo-Li; Zhao, Shi-Fang; He, Fu-Ming

    2011-06-01

    As local gene therapy has received attention, immobilizing functional gene onto irregular oral implant surface has become an advanced challenge. Electrostatic layer-by-layer (LBL) assembly technique could achieve this goal and allow local and efficient administration of genes to the target cells. In this study, multilayers of cationic lipid/plasmid DNA (pEGFP-C1) complex (LDc) and anionic hyaluronic acid were assembled onto sandblasted-dual acid etched titanium disks by the LBL technique. Surface characteristics of the coatings were performed by x-ray photospectroscopy (XPS), contact angle measurements, and scanning electron microscopy (SEM). The cell biological characteristics of the coatings were evaluated by in vitro experiments. SEM results demonstrated that the porous titanium surface was gradually flattened with the increase of the multilayer. The XPS survey indicated that the N element was found from the coating. The coating degradation and pEGFP-C1 releasing kinetics showed that the more assembled layer numbers were, the larger the amount of DNA released in the first 30 h. MC3T3-E1 cells were cultured directly on the DNA-loaded surface. Higher enhanced green fluorescent protein (EGFP) expression efficiency was achieved by increasing the number of layers when cells were cultured after 24 or 72 h. The MC3T3-E1 cell viability on the surface of multilayer DNA coatings was significantly higher than that on control porous titanium surface. It was concluded that the approach established by the LBL technique had great potential in immobilizing gene coatings onto the porous titanium surface and subsequently influenced the function of the cultured cell.

  3. Effect of acid etching of glass ionomer cement surface on the microleakage of sandwich restorations.

    PubMed

    Bona, Alvaro Della; Pinzetta, Caroline; Rosa, Vinícius

    2007-06-01

    The purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs) used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth), assigned to 4 groups (n=10) and restored as follows: Group CIE - conventional GIC (CI) was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E) along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN - same as Group CIE, except for acid etching of the CI surface; Group RME - same as CIE, but using a resin modified GIC (RMGIC); Group RMN - same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24 degrees C for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (a=0.05). Dye penetration scores were as follow: CIE - 2.5; CIN - 2.5; RME - 0.9; and RMN - 0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin composite-dentin interfaces than CI.

  4. Resin Adaptation of Radicular Dentin Tubules after Endodontic Instrumentation and Acid Etching.

    DTIC Science & Technology

    1983-02-01

    the manuscript. DISCLAIMERS The statements, opinions, and advertisements in the Journal of Endodontics are solely those of the individual authors...I RD-Ai26 872 RESIN ADAPTATION OF RADICULAR DENTIN TUBULES AFTER / I ENDODONTIC INSTRUMENTATION AND ACID ETCHING(U) WALTER I REED ARMY INST OF...Adaptation to Radicular Dentin Tubules SbisoofpeAfter Endodontic Instrumentation and Acid Etching 1982-1983 6. PERFORMING ORG. REPORTNUMBER -, AUTHOR(a) S

  5. Bonding durability of single-step adhesives to previously acid-etched dentin.

    PubMed

    Ikeda, Masahiko; Tsubota, Keishi; Takamizawa, Toshiki; Yoshida, Takeshi; Miyazaki, Masashi; Platt, Jeffrey A

    2008-01-01

    This study investigated the effect of phosphoric acid etching on the dentin bond strength of five single-step self-etch adhesive systems; Absolute, Clearfil tri-S Bond, Fluoro Bond Shake One, G-Bond and One-Up Bond F Plus. Bovine mandibular incisors were mounted in self-curing resin and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied on the prepared dentin surfaces with and without prior phosphoric acid etching and light irradiated. Resin composite was condensed into a mold (ø4x2 mm), light irradiated and stored in water at 37 degrees C. Four groups (n=10) were made per adhesive system: with and without prior acid etching and with and without thermal cycling between 5 degrees C and 55 degrees C for 10,000 cycles. The specimens were tested in a shear mode at a crosshead speed of 1.0 mm/minute. Two-way ANOVA, Student t-test and Tukey HSD test at a level of 0.05 were done. For specimens without prior acid etching, the mean bond strengths to bovine dentin ranged from 12.8 to 17.1 MPa and ranged from 6.7 to 13.3 MPa for specimens with prior acid etching after 24 hours storage in water. When the specimens were subjected to thermal cycling, the mean bond strengths ranged from 10.7 to 24.8 MPa for the specimens without prior acid etching and 4.6 to 13.9 MPa for the specimens with prior acid etching. The changes in dentin bond strength were different among the adhesive systems tested. Failure modes were commonly adhesive failure associated with mixed failure for specimens with prior acid etching. For specimens without prior acid etching, failures in composite and dentin were increased. From the results of this in vitro study, prior acid etching might be not acceptable for increasing the dentin bond strengths of single-step self-etch adhesive systems.

  6. Effects of fluoride treatment on phosphoric acid-etching in primary teeth: an AFM observation.

    PubMed

    Choi, Samjin; Rhee, Yeri; Park, Jeong-Hoon; Lee, Gi-Ja; Kim, Kyung-Sook; Park, Jae-Hong; Park, Young-Guk; Park, Hun-Kuk

    2010-07-01

    The aim of this study was to examine the effect of fluoride application on 37% phosphoric acid-etching by atomic force microscopy (AFM) in primary tooth samples based on a clinical protocol used in a pediatric dental hospital. Enamel samples were prepared from 36 exfoliated and non-carious primary teeth. Primary tooth samples were randomly assigned to one of the four groups based on the timing of acid-etching with 37% phosphoric acid after an acidulated phosphate fluoride (APF) pre-treatment. Group 1 received no fluoride application, Group 2 was pre-treated with fluoride and then received acid-etching 2 weeks later. One week separated the fluoride treatment and the acid-etching in Group 3, while Group 4 received acid-etching immediately after the fluoride treatment. The vestibular enamel surfaces of each primary tooth sample were scanned in air at a resolution of 512 x 512 pixels and a scan speed of 0.8 line/s. On the enamel surfaces of the primary teeth after APF pre-treatment, debris were observed although the teeth were smoother than they were prior to APF. As a result, it was concluded that APF treatment is responsible for decreased primary tooth surface roughness. The enamel surfaces etched for 20s showed that acid-etching was effective not only in removing scratches and debris, but also for evaluating enamel rod characteristics. Primary tooth enamel surfaces after etching showed minute structures caused by the decreased hydroxyapatite nanoparticle space, compared to those before etching. Also, acid-etching showed significantly increased roughness effects (p<0.0001, n=9). Finally, as more time elapsed after APF pre-treatment, the roughness was decreased to a lesser degree (p=0.005, n=9). We suggest that primary teeth etching 2 weeks after APF pre-treatment used clinically in pediatric hospitals may be effective to obtain properly etched enamel surfaces.

  7. Effect of prior acid etching on bonding durability of single-step adhesives.

    PubMed

    Watanabe, Takayuki; Tsubota, Keishi; Takamizawa, Toshiki; Kurokawa, Hiroyasu; Rikuta, Akitomo; Ando, Susumu; Miyazaki, Masashi

    2008-01-01

    This study investigated the effect of prior phosphoric acid etching on the enamel bond strength of five single-step self-etch adhesive systems: Absolute, Clearfil tri-S Bond, Fluoro Bond Shake One, G-Bond and One-Up Bond F Plus. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 silicon carbide paper. Adhesives were applied to the enamel surfaces with or without prior phosphoric-acid etching and light irradiated. The resin composites were condensed into a mold and light irradiated. In total, 40 specimens were tested per adhesive system with and without prior acid etching and were further divided into two groups: those stored in water at 37 degrees C for 24 hours without cycling and those stored in water at 37 degrees C for 24 hours followed by thermal cycling between 5 degrees C and 55 degrees C with 10,000 repeats. After storage under each set of conditions, the specimens were tested in shear mode at a crosshead speed of 1.0 mm/minute. Two-way analysis of variance, the Student's t-test and the Tukey HSD test were used to analyze the data at a significance level of 0.05. For the specimens without prior acid etching, the mean bond strengths to enamel ranged from 11.0 to 14.6 MPa after 24-hour storage in water, while the corresponding values for specimens with prior acid etching ranged from 15.2 to 19.3 MPa. When these specimens were subjected to thermal cycling, the mean bond strengths ranged from 11.3 to 17.0 MPa without prior acid etching and from 12.3 to 23.2 MPa with prior acid etching. The changes in enamel bond strengths differed among the adhesive systems tested. After 24-hour storage in water, the most common failure modes were adhesive failure and mixed failure for specimens with and without prior acid etching, respectively. Thus, through a careful choice of adhesive system, prior acid etching can increase the bond strengths of single-step self-etch adhesive systems.

  8. Influence of previous acid etching on bond strength of universal adhesives to enamel and dentin.

    PubMed

    Torres, Carlos Rocha Gomes; Zanatta, Rayssa Ferreira; Silva, Tatiane Josefa; Huhtala, Maria Filomena Rocha Lima; Borges, Alessandra Bühler

    2017-01-01

    The objective of this study was to evaluate the effect of acid pretreatment on the bond strength of composite resin bonded to enamel and dentin with 2 different universal self-etching adhesives. The null hypothesis was that the acid treatment performed prior to adhesive application would not significantly change the bond strength to enamel or dentin for either universal adhesive tested. A sample of 112 bovine incisors were selected and embedded in acrylic resin. Half were ground until a flat enamel surface was obtained, and the other half were polished until a 6 × 6-mm area of dentin was exposed, resulting into 2 groups (n = 56). The enamel and dentin groups were divided into 2 subgroups according to the adhesive system applied: Futurabond U or Scotchbond Universal. Each of these subgroups was divided into 2 additional subgroups (n = 14); 1 subgroup received phosphoric acid pretreatment, and 1 subgroup did not. The bond strength was assessed with a microtensile test. Data from enamel and dentin specimens were analyzed separately using 1-way analysis of variance. The acid pretreatment did not significantly change the bond strength of the adhesives tested, either to enamel (P = 0.4161) or to dentin (P = 0.4857). The acid etching pretreatment did not affect the bond strength to dentin and enamel when the tested universal multipurpose adhesive systems were used.

  9. Effect of acid-etching on remineralization of enamel white spot lesions.

    PubMed

    Al-Khateeb, S; Exterkate, R; Angmar-Månsson, B; ten Cate, J M; ten Cate, B

    2000-02-01

    This in vitro study aimed at investigating whether full remineralization would occur in white spot lesions when the surface porosity was increased by acid-etching. The effect of fluoride was also investigated. Enamel blocks with in vitro produced white spot lesions were used. Group A was exposed to a remineralizing solution only. In group B, the lesions were etched with 35% phosphoric acid for 30 s, then treated as in group A. Group C was treated as group A + daily treatment with a fluoride toothpaste slurry (1,000 ppm) for 5 min. Group D was treated as group B + the daily fluoride treatment of group C. The remineralization was measured weekly with Quantitative Light-induced Fluorescence during the experimental period. After 10 weeks of remineralization, mineral profiles were assessed with transverse microradiography. The enamel fluorescence was partly regained. There were significant differences in the lesion depth, mineral content at the surface layer, and integrated mineral loss between the groups. Addition of fluoride accelerated the remineralization only in the beginning; in later stages the process leveled out and even reached a plateau in all the groups. It was concluded that full remineralization was not achieved by etching, by the addition of fluoride, nor by the combination of both treatments in this in vitro study.

  10. In vitro short-term bonding performance of zirconia treated with hot acid etching and primer conditioning etching and primer conditioning.

    PubMed

    Xie, Haifeng; Chen, Chen; Dai, Wenyong; Chen, Gang; Zhang, Feimin

    2013-01-01

    This study aimed to investigate and compare the resin bond strengths of zirconia conditioned as follows: alumina sandblasting; alumina sandblasting+application of 10-MDP-containing primer; alumina sandblasting+application of Z-Prime Plus or Metal/Zirconia Primer (new zirconia primers); tribochemical silica coating+silanization; hot acid etching in three different combinations [H2SO4/(NH4)2SO4, HF/HNO3, H2SO4/HF/HNO3]+application of 10-MDP-containing primer. Shear bond strengths (SBS) after water storage for 24 h and 40 days were measured to assess resin bonding performance. Surface and chemical properties of conditioned zirconia surfaces and primers were characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, Fourier transform infrared spectroscopy, and atomic force microscopy. Surface roughness ranked in descending order was: hot acid etching > tribochemical silica coating > alumina sandblasting. Combination of tribochemical silica coating and silanization showed the highest initial SBS (12.46±2.13 MPa) (P<0.01). Etching with H2SO4/(NH4)2SO4 (13.15±3.24 MPa) and HF/HNO3 (13.48±2.15 MPa) showed significantly better bond durability (P<0.01). Hot acid etching seemed to be a promising surface roughening treatment to improve resin-zirconia bonding.

  11. Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

    PubMed

    Imbery, Terence A; Kennedy, Matthew; Janus, Charles; Moon, Peter C

    2012-01-01

    Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P < 0.05). EDTA was successfully substituted for phosphoric acid-etched enamel and dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

  12. Instrumentation With Ultrasonic Scalers Facilitates Cleaning of the Sandblasted and Acid-Etched Titanium Implants.

    PubMed

    Park, Jun-Beom; Lee, Sung-Hoon; Kim, NamRyang; Park, Seojin; Jin, Seong-Ho; Choi, Bong-Kyu; Kim, Kack-Kyun; Ko, Youngkyung

    2015-08-01

    Mechanical instrumentation is widely used to debride dental implants, but this may alter the surface properties of titanium, which in turn may influence bacterial adhesion and make it more difficult to remove the biofilm. This in vitro study was performed (1) to assess the amount of biofilm formation on a sand-blasted and acid-etched titanium fixture treated with ultrasonic scalers with metal, plastic, and carbon tips and (2) to evaluate how this treatment of titanium surfaces affects implant cleaning by brushing with dentifrice. The titanium fixtures were treated with various ultrasonic scaler tips, and surface roughness parameters were measured by confocal microscopy. Biofilm was formed on the treated fixtures by using pooled saliva from 10 subjects, and the quantity of the adherent bacteria was compared with crystal violet assay. The fixture surfaces with biofilm were brushed for total of 30 seconds with a toothbrush with dentifrice. The bacteria remaining on the brushed fixture surfaces were quantified by scanning electron microscopy. Surface changes were evident, and the changes of the surfaces were more discernible when metal tips were used. A statistically significant decrease in roughness value (arithmetic mean height of the surface) was seen in the 2 metal-tip groups and the single plastic-tip group. After brushing with dentifrice, the treated surfaces in all the treatment groups showed significantly fewer bacteria compared with the untreated surfaces in the control group, and the parts of the surfaces left untreated in the test groups. Within the limits of this study, treatment of titanium fixture surfaces with ultrasonic metal, plastic, or carbon tips significantly enhanced the bacterial removal efficacy of brushing. Thorough instrumentation that smooths the whole exposed surface may facilitate maintenance of the implants.

  13. Strength determination of periodontal splints fabricated from acid-etched retained materials.

    PubMed

    Compton, F H; Beagrie, G S; Chernecky, R

    1977-07-01

    Six systems (one polycarboxylate, one polymethyl methacrylate, one unfilled BIS-GMA resin, two combinations of methyl cyanoacrylate and polymethyl methacrylate, and one combination of unfilled BIS-GMA and filled composite resin) were evaluated for in vitro retention to acid-etched human enamel. Also tested were one unfilled-filled resin combination backed by perforated orthodontic band metal and another unfilled resin backed by stainless steel wire mesh. Significant differences in retention were found. Results show that retention depends pril surface and to resist subsequent chemical degradation.

  14. Cell adhesion and in vivo osseointegration of sandblasted/acid etched/anodized dental implants.

    PubMed

    Kim, Mu-Hyon; Park, Kyeongsoon; Choi, Kyung-Hee; Kim, Soo-Hong; Kim, Se Eun; Jeong, Chang-Mo; Huh, Jung-Bo

    2015-05-06

    The authors describe a new type of titanium (Ti) implant as a Modi-anodized (ANO) Ti implant, the surface of which was treated by sandblasting, acid etching (SLA), and anodized techniques. The aim of the present study was to evaluate the adhesion of MG-63 cells to Modi-ANO surface treated Ti in vitro and to investigate its osseointegration characteristics in vivo. Four different types of Ti implants were examined, that is, machined Ti (control), SLA, anodized, and Modi-ANO Ti. In the cell adhesion study, Modi-ANO Ti showed higher initial MG-63 cell adhesion and induced greater filopodia growth than other groups. In vivo study in a beagle model revealed the bone-to-implant contact (BIC) of Modi-ANO Ti (74.20%±10.89%) was much greater than those of machined (33.58%±8.63%), SLA (58.47%±12.89), or ANO Ti (59.62%±18.30%). In conclusion, this study demonstrates that Modi-ANO Ti implants produced by sandblasting, acid etching, and anodizing improve cell adhesion and bone ongrowth as compared with machined, SLA, or ANO Ti implants. These findings suggest that the application of Modi-ANO surface treatment could improve the osseointegration of dental implant.

  15. Acid-etched microtexture for enhancement of bone growth into porous-coated implants.

    PubMed

    Hacking, S A; Harvey, E J; Tanzer, M; Krygier, J J; Bobyn, J D

    2003-11-01

    We designed an in vivo study to determine if the superimposition of a microtexture on the surface of sintered titanium beads affected the extent of bone ingrowth. Cylindrical titanium intramedullary implants were coated with titanium beads to form a porous finish using commercial sintering techniques. A control group of implants was left in the as-sintered condition. The test group was etched in a boiling acidic solution to create an irregular surface over the entire porous coating. Six experimental dogs underwent simultaneous bilateral femoral intramedullary implantation of a control implant and an acid etched implant. At 12 weeks, the implants were harvested in situ and the femora processed for undecalcified, histological examination. Eight transverse serial sections for each implant were analysed by backscattered electron microscopy and the extent of bone ingrowth was quantified by computer-aided image analysis. The extent of bone ingrowth into the control implants was 15.8% while the extent of bone ingrowth into the etched implants was 25.3%, a difference of 60% that was statistically significant. These results are consistent with other research that documents the positive effect of microtextured surfaces on bone formation at an implant surface. The acid etching process developed for this study represents a simple method for enhancing the potential of commonly available porous coatings for biological fixation.

  16. Surface characterization of alkali- and heat-treated Ti with or without prior acid etching

    NASA Astrophysics Data System (ADS)

    An, Sang-Hyun; Matsumoto, Takuya; Miyajima, Hiroyuki; Sasaki, Jun-Ichi; Narayanan, Ramaswamy; Kim, Kyo-Han

    2012-03-01

    Titanium and its alloys are used as implant materials in dental and orthopaedic applications. The material affinities to host bone tissue greatly concern with the recovery period and good prognosis. To obtain a material surface having excellent affinity to bone, acid etching prior to alkali- and heat-treatment of Ti was conducted. The surface characteristics of the prepared sample indicated that the roughness as well as the wettability increased by pre-etching. Bone-like apatite was formed on pre-etched, alkali- and heat-treated Ti surface in simulated body fluid (SBF) within 3 days, while it takes 5 days on the solely alkali- and heat-treated surface. Osteoblastic cells showed better compatibility on the per-etched surface compared to the pure Ti surface or alkali- and heat-treated surface. Moreover, the pre-etched surface showed better pull-off tensile adhesion strength against the deposited apatite. Thus, acid etching prior to alkali- and heat-treatment would be a promising method for enhancing the affinity of Ti to host bone tissue.

  17. In Vitro Evaluation of Microleakage Around Orthodontic Brackets Using Laser Etching and Acid Etching Methods

    PubMed Central

    Toodehzaeim, Mohammad Hossein; Yassaei, Sogra; Karandish, Maryam; Farzaneh, Sedigeh

    2014-01-01

    Objective: path of microleakage between the enamel and adhesive potentially allows microbial ingress that may consequently cause enamel decalcification. The aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques. Materials and Method: The specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1), laser etching with Er:YAG at 100 mJ and 15 Hz for 15s (group 2), and laser etching with Er:YAG at 140 mJ and 15 Hz for 15s (group 3). After photo polymerization, the teeth were subjected to 500 thermal cycles. Then the specimens were sealed with nail varnish, stained with 2% methylen blue for 24hs, sectioned, and examined under a stereomicroscope. They were scored for marginal microleakage that occurred between the adhesive-enamel and bracket-adhesive interfaces from the occlusal and gingival margins. Data were analyzed with the Kruskal- Wallis test. Results: For the adhesive-enamel and bracket-adhesive surfaces, significant differences were not observed between the three groups. Conclusion: According to this study, the Er:YAG laser with 1.5 and 2.1 watt settings may be used as an adjunctive for preparing the surface for orthodontic bracket bonding. PMID:25628661

  18. In vitro remineralization of acid-etched human enamel with Ca 3SiO 5

    NASA Astrophysics Data System (ADS)

    Dong, Zhihong; Chang, Jiang; Deng, Yan; Joiner, Andrew

    2010-02-01

    Bioactive and inductive silicate-based bioceramics play an important role in hard tissue prosthetics such as bone and teeth. In the present study, a model was established to study the acid-etched enamel remineralization with tricalcium silicate (Ca 3SiO 5, C 3S) paste in vitro. After soaking in simulated oral fluid (SOF), Ca-P precipitation layer was formed on the enamel surface, with the prolonged soaking time, apatite layer turned into density and uniformity and thickness increasingly from 250 to 350 nm for 1 day to 1.7-1.9 μm for 7 days. Structure of apatite crystals was similar to that of hydroxyapatite (HAp). At the same time, surface smoothness of the remineralized layer is favorable for the oral hygiene. These results suggested that C 3S treated the acid-etched enamel can induce apatite formation, indicating the biomimic mineralization ability, and C 3S could be used as an agent of inductive biomineralization for the enamel prosthesis and protection.

  19. Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

    NASA Astrophysics Data System (ADS)

    Costescu, Ruxandra M.; Deneke, Christoph; Thurmer, Dominic J.; Schmidt, Oliver G.

    2009-12-01

    The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The “etch suppression” area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

  20. Hydrogen content in titanium and a titanium-zirconium alloy after acid etching.

    PubMed

    Frank, Matthias J; Walter, Martin S; Lyngstadaas, S Petter; Wintermantel, Erich; Haugen, Håvard J

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (p<0.01) on the titanium-zirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium.

  1. Effects of laser and acid etching and air abrasion on mineral content of dentin.

    PubMed

    Malkoc, Meral Arslan; Taşdemir, Serife Tuba; Ozturk, A Nilgun; Ozturk, Bora; Berk, Gizem

    2011-01-01

    The aim of this study was to evaluate the mineral content of dentin prepared using an Er,Cr:YSGG laser at four different power settings, acid etching, and air abrasion. The study teeth comprised 35 molars which were randomly divided into seven equal groups. The occlusal third of the crowns were cut with a slow-speed diamond saw. The groups were as follows: group A, control group; group B, dentin etched with 35% buffered phosphoric acid for 30 s; group C, dentin abraded at 60 psi with 50-µm aluminium oxide for 1 s; groups D-G, dentin irradiated with the Er,Cr:YSGG laser at 1.50 W (group D), 2.25 W (group E), 3.00 W (group F), and 3.50 W (group G). The levels of Mg, P, Ca, K and Na in each dentin slab were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Data were analysed by one way analysis of variance and Tukey HSD tests. There were no significant differences between the groups in the levels of Ca, P and Na, and the Ca/P ratio (p>0.05); however, there were significant differences in the levels of K (p<0.001) and Mg (p=0.13). In addition, the levels of Mg in the air abrasion group were higher than in the other groups (p<0.01). Etching with the Er,Cr:YSGG laser system, air abrasion and acid etching did not affect the levels of Ca, P and Na, or the Ca/P ratio, in the dentin surface.

  2. Shear bond strength of resin cement to an acid etched and a laser irradiated ceramic surface

    PubMed Central

    Motro, Pelin Fatma Karagoz; Yurdaguven, Haktan

    2013-01-01

    PURPOSE To evaluate the effects of hydrofluoric acid etching and Er,Cr:YSGG laser irradiation on the shear bond strength of resin cement to lithium disilicate ceramic. MATERIALS AND METHODS Fifty-five ceramic blocks (5 mm × 5 mm × 2 mm) were fabricated and embedded in acrylic resin. Their surfaces were finished with 1000-grit silicon carbide paper. The blocks were assigned to five groups: 1) 9.5% hydrofluoric-acid etching for 60 s; 2-4), 1.5-, 2.5-, and 6-W Er,Cr:YSGG laser applications for 60 seconds, respectively; and 5) no treatment (control). One specimen from each group was examined using scanning electron microscopy. Ceramic primer (Rely X ceramic primer) and adhesive (Adper Single Bond) were applied to the ceramic surfaces, followed by resin cement to bond the composite cylinders, and light curing. Bonded specimens were stored in distilled water at 37℃ for 24 hours. Shear bond strengths were determined by a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests (α=0.05). RESULTS Adhesion was significantly stronger in Group 2 (3.88 ± 1.94 MPa) and Group 3 (3.65 ± 1.87 MPa) than in Control group (1.95 ± 1.06 MPa), in which bonding values were lowest (P<.01). No significant difference was observed between Group 4 (3.59 ± 1.19 MPa) and Control group. Shear bond strength was highest in Group 1 (8.42 ± 1.86 MPa; P<.01). CONCLUSION Er,Cr:YSGG laser irradiation at 1.5 and 2.5 W increased shear bond strengths between ceramic and resin cement compared with untreated ceramic surfaces. Irradiation at 6 W may not be an efficient ceramic surface treatment technique. PMID:23755333

  3. Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

    PubMed Central

    Soares, Ana Flávia; Bombonatti, Juliana Fraga Soares; Alencar, Marina Studart; Consolmagno, Elaine Cristina; Honório, Heitor Marques; Mondelli, Rafael Francisco Lia

    2016-01-01

    ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10), each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL) or diode laser/violet LED (VHL) (experimental): Control (C); 35% Total Blanc Office (TBO35HL); 35% Lase Peroxide Sensy (LPS35HL); 25% Lase Peroxide Sensy II (LPS25HL); 15% Lase Peroxide Lite (LPL15HL); and 10% hydrogen peroxide (experimental) (EXP10VHL). pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm). ANOVA and Tukey´s tests were applied (α=0.05). Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups. PMID:27008254

  4. Investigation of acid-etched CO2 laser ablated enamel surfaces using polarization sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Nahm, Byung J.; Kang, Hobin; Chan, Kenneth; Fried, Daniel

    2012-01-01

    A carbon dioxide laser operating at the highly absorbed wavelength of 9.3μm with a pulse duration of 10-15μs is ideally suited for caries removal and caries prevention. The enamel thermally modified by the laser has enhanced resistance to acid dissolution. This is an obvious advantage for caries prevention; however, it is often necessary to etch the enamel surface to increase adhesion to composite restorative materials and such surfaces may be more resistant to etching. The purpose of the study was to non-destructively measure the susceptibility of laser-ablated enamel surfaces to acid dissolution before and after acid-etching using Polarization Sensitive Optical Coherence Tomography (PS-OCT). PS-OCT was used to acquire images of bovine enamel surfaces after exposure to laser irradiation at ablative fluence, acid-etching, and a surface softened dissolution model. The integrated reflectivity from lesion and the lesion depth were measured using PS-OCT. Samples were also sectioned for examination by Polarized Light Microscopy (PLM). PS-OCT images showed that acid-etching greatly accelerated the formation of subsurface lesions on both laser-irradiated and non-irradiated surfaces (P<0.05). A 37.5% phosphoric acid etch removed the laser modified enamel layer after 5-10 seconds.

  5. Ultrastructure of the surface of dental enamel with molar incisor hypomineralization (MIH) with and without acid etching.

    PubMed

    Bozal, Carola B; Kaplan, Andrea; Ortolani, Andrea; Cortese, Silvina G; Biondi, Ana M

    2015-01-01

    The aim of the present work was to analyze the ultrastructure and mineral composition of the surface of the enamel on a molar with MIH, with and without acid etching. A permanent tooth without clinical MIH lesions (control) and a tooth with clinical diagnosis of mild and moderate MIH, with indication for extraction, were processed with and without acid etching (H3PO4 37%, 20") for observation with scanning electron microscope (SEM) ZEISS (Supra 40) and mineral composition analysis with an EDS detector (Oxford Instruments). The control enamel showed normal prismatic surface and etching pattern. The clinically healthy enamel on the tooth with MIH revealed partial loss of prismatic pattern. The mild lesion was porous with occasional cracks. The moderate lesion was more porous, with larger cracks and many scales. The mineral composition of the affected surfaces had lower Ca and P content and higher O and C. On the tooth with MIH, even on normal looking enamel, the demineralization does not correspond to an etching pattern, and exhibits exposure of crystals with rods with rounded ends and less demineralization in the inter-prismatic spaces. Acid etching increased the presence of cracks and deep pores in the adamantine structure of the enamel with lesion. In moderate lesions, the mineral composition had higher content of Ca, P and Cl. Enamel with MIH, even on clinically intact adamantine surfaces, shows severe alterations in the ultrastructure and changes in ionic composition, which affect the acid etching pattern and may interfere with adhesion.

  6. Effect of Acid Etching, Silane and Thermal Cycling on the Bond Strength of Metallic Brackets to Ceramic.

    PubMed

    Matos, Natália Regina Santos de; Costa, Ana Rosa; Valdrighi, Heloísa Cristina; Correr, Américo Bortolazzo; Vedovello, Silvia Amélia; Santamaria, Milton; Correr-Sobrinho, Lourenço

    2016-01-01

    The aim of this study was to evaluate the effect of silanes, thermal cycling and acid etching on the shear bond strength (SBS) of metallic brackets to feldspathic ceramic. Feldspathic ceramic cylinders (Groups 1, 2, 5 and 6) were etched for 60 s with 10% hydrofluoric acid and Groups 3, 4, 7 and 8, without acid etching. Two layers of silane Clearfil Ceramic Primer (CCP, Groups 1 to 4) and two layers of RelyX Ceramic Primer (RCP, groups 5 to 8) were applied and dried for 60 s. Brackets were bonded to the cylinders with Transbond XT and light-activated for 40 s with Bluephase G2. All specimens were stored in deionized water at 37 °C for 24 h, and the specimens of groups 1, 3, 5 and 7 were submitted to 7,000 thermal cycles (5 °C/55 °C). After storage, the SBS test was performed at a crosshead speed of 1 mm/min. Data were subjected to three-way ANOVA and Tukey's post hoc test (α=0.05). The adhesive remnant index (ARI) was evaluated at 8x magnification. The SBS of CCP was significantly greater than of RCP (p<0.05), with or without thermal cycling. Thermal cycling significantly reduced the SBS (p<0.05). The groups submitted to acid etching showed significantly higher SBS than those without acid etching (p<0.05). In conclusion, thermal cycling reduced SBS for all groups. The best ceramic surface treatment for bracket bonding was achieved by acid etching and CCP silane. The ARI results showed predominance of score 0 for all groups.

  7. Improvement of enamel bond strengths for conventional and resin-modified glass ionomers: acid-etching vs. conditioning*

    PubMed Central

    Zhang, Ling; Tang, Tian; Zhang, Zhen-liang; Liang, Bing; Wang, Xiao-miao; Fu, Bai-ping

    2013-01-01

    Objective: This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths (μTBSs) of conventional and resin-modified glass ionomer cements (GICs/RMGICs). Methods: Forty-eight bovine incisors were prepared into rectangular blocks. Highly-polished labial enamel surfaces were either acid-etched, conditioned with liquids of cements, or not further treated (control). Subsequently, two matching pre-treated enamel surfaces were cemented together with one of four cements [two GICs: Fuji I (GC), Ketac Cem Easymix (3M ESPE); two RMGICs: Fuji Plus (GC), RelyX Luting (3M ESPE)] in preparation for μTBS tests. Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy (SEM). Results: Phosphoric acid etching significantly increased the enamel μTBS of GICs/RMGICs. Conditioning with the liquids of the cements produced significantly weaker or equivalent enamel μTBS compared to the control. Regardless of etching, RMGICs yielded stronger enamel μTBS than GICs. A visible hybrid layer was found at certain enamel-cement interfaces of the etched enamels. Conclusions: Phosphoric acid etching significantly increased the enamel μTBSs of GICs/RMGICs. Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays, using GICs/RMGICs to improve the bond strengths. RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength. PMID:24190447

  8. Surface Properties and Osteoblastic Cytocompatibility of Two Blasted and Acid-Etched Titanium Implant Systems with Distinct Microtopography

    PubMed Central

    Mesquita, Pedro; Gomes, Pedro de Sousa; Sampaio, Paula; Juodzbalys, Gintaras; Afonso, Américo

    2012-01-01

    ABSTRACT Objectives The aim of this study is to compare two commercially available screw-type sandblasted and acid-etched (SLA) Ti implant systems from Eckermann Laboratorium S.L., with similar geometry and distinct microtopography, regarding surface properties and osteoblastic cytocompatibility. Material and Methods Implant I (referred as a conventional SLA system) and Implant II (a system patented as Eckcyte®) were characterized for macro and microtopograpphy, surface roughness and chemical composition. For the cytocompatibility studies, human bone marrow osteoblastic cells were seeded over the implants' surface, and the cell response was assessed for cell adhesion and proliferation, alkaline phosphatase (ALP) activity and matrix mineralization. Results Implant I presented a rough surface with irregularly shaped and sized cavities among flatter-appearing areas, whereas Implant II exhibited a homogeneous rough microporous surface. Compared to Implant I, Implant II presented higher Ra values (0.8 [SD 0.008] μm and 1.21 [SD 0.15] μm, respectively, P < 0.05) and also increased values of Rz, Rt and Rsm, a more negative value of Rsk, and similar RKu values. XPS showed the expected presence of Ti, O, C and N; Al, Si, F, P and Ca were detected in low concentrations. Implant II exhibited significantly lower Al levels. Both implants supported the adhesion, proliferation and differentiation of osteoblastic cells. Implant II showed a thicker fibrilar cell layer and an earlier onset and more abundant matrix mineralization. Conclusions The homogeneous rough and microporous surface of Implant II is most probably a main contributor for its improved cell response. PMID:24422006

  9. Noble Gases and Nitrogen Released from a Lunar Soil Pyroxene Separate by Acid Etching

    NASA Astrophysics Data System (ADS)

    Rider, P. E.

    1993-07-01

    We report initial results from a series of experiments designed to measure recently implanted solar wind (SW) ions in lunar soil mineral grains [1]. An acid-etching technique similar to the CSSE method developed at ETH Zurich was used to make abundance and isotope measurements of the SW noble gas and nitrogen compositions. Among the samples examined was a pyroxene separate from soil 75081. It was first washed with H2O to remove contamination from the sample finger walls and grain surfaces. H2O also acted as a weak acid, releasing gases from near-surface sites. Treatment with H2SO3 followed the water washes. Acid pH (~1.8 to ~1.0) and temperature (~23 degrees C to ~90 degrees C) and duration of acid attack (several minutes to several days) were varied from step to step. Finally, the sample was pyrolyzed in several steps to remove the remaining gases, culminating with a high-temperature pyrolysis at 1200 degrees C. Measurements of the light noble gases were mostly consistent with those from previous CSSE experiments performed on pyroxene [2,3]. It should be noted, however, that the Zurich SEP component was not easily distinguishable in the steps where it was expected to be observed. We suspect our experimental protocol masked the SEP reservoir, preventing us from seeing its distinctive signature. The most interesting results from this sample are its Kr and Xe isotopic and elemental compositions. Pyroxene apparently retains heavy noble gases as well as ilmenite (and plagioclase [4]). The heavy noble gas element ratios from this sample along with those previously reported [5,6] are, however, considerably heavier than the theoretically determined "solar system" values [7,8]. Explanations for the difference include the possibility that the derivations are incorrect, that there is another component of lunar origin mixing with the solar component, or that some type of loss mechanism is altering the noble gas reservoirs of the grains. The Kr and Xe isotopic compositions for

  10. Comparison of Self-Etch Primers with Conventional Acid Etching System on Orthodontic Brackets

    PubMed Central

    Zope, Amit; Zope-Khalekar, Yogita; Chitko, Shrikant S.; Kerudi, Veerendra V.; Patil, Harshal Ashok; Jaltare, Pratik; Dolas, Siddhesh G

    2016-01-01

    Introduction The self-etching primer system consists of etchant and primer dispersed in a single unit. The etching and priming are merged as a single step leading to fewer stages in bonding procedure and reduction in the number of steps that also reduces the chance of introduction of error, resulting in saving time for the clinician. It also results in smaller extent of enamel decalcification. Aim To compare the Shear Bond Strength (SBS) of orthodontic bracket bonded with Self-Etch Primers (SEP) and conventional acid etching system and to study the surface appearance of teeth after debonding; etching with conventional acid etch and self-etch priming, using stereomicroscope. Materials and Methods Five Groups (n=20) were created randomly from a total of 100 extracted premolars. In a control Group A, etching of enamel was done with 37% phosphoric acid and bonding of stainless steel brackets with Transbond XT (3M Unitek, Monrovia, California). Enamel conditioning in left over four Groups was done with self-etching primers and adhesives as follows: Group B-Transbond Plus (3M Unitek), Group C Xeno V+ (Dentsply), Group D-G-Bond (GC), Group E-One-Coat (Coltene). The Adhesive Remnant Index (ARI) score was also evaluated. Additionally, the surface roughness using profilometer were observed. Results Mean SBS of Group A was 18.26±7.5MPa, Group B was 10.93±4.02MPa, Group C was 6.88±2.91MPa while of Group D was 7.78±4.13MPa and Group E was 10.39±5.22MPa respectively. In conventional group ARI scores shows that over half of the adhesive was remaining on the surface of tooth (score 1 to 3). In self-etching primer groups ARI scores show that there was no or minor amount of adhesive remaining on the surface of tooth (score 4 and 5). SEP produces a lesser surface roughness on the enamel than conventional etching. However, statistical analysis shows significant correlation (p<0.001) of bond strength with surface roughness of enamel. Conclusion All groups might show clinically

  11. Comparative Evaluation of Tensile – Bond Strength of An Orthodontic Adhesive with and without Fluoride Application, After Acid Etching -An Invitro Study

    PubMed Central

    Yugandhar, G; Ramana, I Venkata; Srinivas, K; Yadav, S. Sarjeev Singh

    2015-01-01

    Background Fixed appliances hinder the effective control of plaque accumulation and white spot lesions may develop under the ill fitting bands or adjacent to the stainless steel brackets during orthodontic treatment particularly the etching process. Aims and Objectives Comparative study of tensile bond strength of an orthodontic adhesive with and without fluoride application after acid etching to know the effect of fluoride on bond strength. Materials and Methods This study is carried out on 90 non carious human premolar teeth, and divided in 6 groups with each group of 15 specimens. In those Groups I and IV were control group acid etch treatment, Group II and V is 1.23% APF gel (acid etch plus APF gel treatment,) and group III and VI is 8% SnF2 (acid etch plus SnF2 treatment). Samples of Group I, II and III bond strength were tested after 24 h and groups IV, V and VI after one month on microtechtensometer machine. The scanning electron microscope (SEM) investigation was carried out for the 2 specimens for the control group after acid etch and 4 specimens after acid etch with fluoride application for fluoride groups. Results Control and SnF2 treated groups was found to be nearly similar to the control group whereas APF treated group showed less focal holes than the other 2 groups. Conclusion Fluoride application after acid etching without having an adverse effect on bond strength but we can prevent the white spot lesions and caries. PMID:26023648

  12. Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion

    PubMed Central

    Zahran, R.; Rosales Leal, J. I.; Rodríguez Valverde, M. A.; Cabrerizo Vílchez, M. A.

    2016-01-01

    Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF) acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5–7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time. PMID:27824875

  13. Comparative Study of the Effect of Acid Etching on Enamel Surface Roughness between Pumiced and Non-pumiced Teeth

    PubMed Central

    Abreu, Lucas Guimarães; Paiva, Saul Martins; Pretti, Henrique; Lages, Elizabeth Maria Bastos; Júnior, João Batista Novães; Ferreira, Ricardo Alberto Neto

    2015-01-01

    Background: The objective was to perform a comparative analysis of the effect of acid etching on enamel roughness between pumiced and non-pumiced teeth. Materials and Methods: The sample was composed of 32 dental surfaces divided into two groups: Group 1-16 surfaces having received pumice prophylaxis; and Group 2-16 surfaces not having received pumice prophylaxis. The teeth were kept in saline until the first record of surface roughness prior to etching. For each surface, a roughness graph was obtained through trials using a surface roughness tester. This procedure was repeated two more times at different locations for a total of three readings which, later, were converted in a mean value. The teeth were then acid etched with a 37% phosphoric acid for 60 s, rinsed with water, air dried, and tested with the roughness tester again using the same protocol described for baseline. The Quantikov image analysis program was used to measure the length of the graphs. The average value of the lengths was recorded for each surface before and after etching. The increase in roughness caused by acid etching was calculated and compared between groups. Results: The mean increase in roughness caused by the etching was 301 µm (11.37%) in Group 1 and 214 µm (8.33%) in Group 2. No statistically significant difference was found between samples with and without pumice prophylaxis (P = 0.283). Conclusion: The present study showed that the effect of acid etching on enamel roughness was not significantly affected by prior pumice prophylaxis. PMID:26435607

  14. Inactivation of Matrix-bound MMPs by Cross-linking Agents in Acid Etched Dentin

    PubMed Central

    Scheffel, Débora Lopes Salles; Hebling, Josimeri; Scheffel, Régis Henke; Agee, Kelly A.; Turco, Gianluca; de Souza Costa, Carlos Alberto; Pashley, David H.

    2014-01-01

    Objectives Published TEM analysis of in vivo resin-dentin bonds shows that in 44 months almost 70% of collagen fibrils from the hybrid layer disappear. Matrix metalloproteinases (MMPs) play an important role in that process and are thought to be the main factor responsible for the solubitization of dentin collagen. Therefore, this study aimed to evaluate the inactivation of matrix-bound MMPs by carbodiimide (EDC) or proanthocyanidin (PA) both cross-linking agents, or the MMP-inhibitor, chlorhexidine (CHX), on acid-etched dentin using a simplified MMP assay method. Methods Dentin beams (1×1×6mm) were obtained from mid-coronal dentin of sound third molars and randomly divided into 6 groups (G) according to the dentin treatment: G1: Deionized water (control), G2: 0.1M EDC, G3: 0.5M EDC, G4: 0.5M EDC+35% HEMA, G5: 5% Proanthocyanidin (PA) and G6: 2% CHX. The beams were etched for 15s with 37% phosphoric acid, rinsed and then immersed for 60s in one of the treatment solutions. The total MMP activity of dentin was analyzed for 1 h by colorimetric assay (Sensolyte). Data were submitted to Wilcoxon non-parametric test and Mann-Whitney tests (p>0.05). Results All experimental cross-linking solutions significantly reduced MMP activity compared to control, except 0.1M EDC (53.6% ±16.1). No difference was observed between cross-linking agents and 2% CHX 0.5M EDC + 35% HEMA (92.3% ±8.0) was similar to 0.5M EDC (89.1% ±6.4), 5% PA (100.8% ±10.9) and 2% CHX (83.4% ±10.9). Conclusion Dentin treatment with cross-linking agents is effective to significantly reduce MMP activity. Mixing 0.5M EDC and 35% HEMA did not influence EDC inhibitor potential. PMID:23786610

  15. In vitro evaluation of microleakage under orthodontic brackets using two different laser etching, self etching and acid etching methods.

    PubMed

    Hamamci, Nihal; Akkurt, Atilim; Başaran, Güvenç

    2010-11-01

    This study evaluated the microleakage of brackets bonded by four different enamel etching techniques. Forty freshly extracted human premolars were divided randomly into four equal groups and received the following treatment: group 1, acid etching; group 2, self-etching primer (SEP); group 3, erbium:yttrium-aluminum-garnet (Er:YAG) laser etching; and group 4, erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching. After photopolymerization, the teeth were kept in distilled water for 1 month and then subjected to 500 thermal cycles. Then, the specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 h, sectioned, and examined under a stereomicroscope. In addition, they were scored for marginal microleakage at the adhesive-enamel and bracket-adhesive interfaces from the incisal and gingival margins. Statistical analyses consisted of the Kruskal-Wallis test and the Mann-Whitney U test with Bonferroni correction. Microleakage occurred between the adhesive-enamel and bracket-adhesive interfaces in all groups. For the adhesive-enamel surface, a significant difference was observed between group 1 and groups 2 (P = 0.011), 3 (P = 0.002), and 4 (P = 0.000) on the gingival side. Overall, significant differences were observed between group 1 and groups 3 (P = 0.003) and 4 (P = 0.000). In dental bonding procedures, acid etching was found to result in the least microleakage. Since etching with a laser decreases the risk of caries and is time-saving, it may serve as an alternative to acid etching.

  16. The effect of topical fluorides, after acid etching of enamel, on the bond strength of directly bonded orthodontic brackets.

    PubMed

    Hirce, J D; Sather, A H; Chao, E Y

    1980-10-01

    This study tests the hypothesis that the beneficial effects of topical fluoride can be realized without reducing the bond strength of the resin adhesive. Twenty-eight groups of four teeth (third molars and premolars) were extracted from twenty-eight patients and stored in distilled water. Twin brackets on Ormesh pads were bonded to all teeth with Endur adhesive. One tooth from each group was bonded according to the manufacturer's instructions. These teeth, Subgroup I, served as controls. Subgroup II teeth were etched for 4 minutes with 50% phosphoric acid containing 2 percent sodium fluoride. Subgroup III teeth received a 3-minute application of a basic phosphate fluoride solution (10(-2)M NA3PO4, 10(3) ppm F) after 1 minute of etching with 50 percent phosphoric acid. Subgroup IV teeth received a 4-minute application of 8 percent stannous fluoride solution after 1 minute of etching with 50 percent phosphoric acid. Each tooth was mounted in a block of improved dental stone; guide wires were used to reproduce bracket orientation. The M.T.S. materials-testing apparatus was used to generate a torsional moment on the bracket at a rate of 1 degree per second. Fluoride uptake by enamel has been shown to be greater in an acid medium or after acid etching. The application of directly bonded orthodontic brackets and pit-and-fissure sealants requires acid etching of the enamel surface. This study supports the use of topical fluoride after acid etching, a procedure that achieves the benefits of increased fluoride uptake without changing the bond strength of the resin adhesive.

  17. Effect of acid etching duration on tensile bond strength of composite resin bonded to erbium:yttrium-aluminium-garnet laser-prepared dentine. Preliminary study.

    PubMed

    Chousterman, M; Heysselaer, D; Dridi, S M; Bayet, F; Misset, B; Lamard, L; Peremans, A; Nyssen-Behets, C; Nammour, S

    2010-11-01

    The purpose of this study was to compare the tensile bond strength of composite resin bonded to erbium:yttrium-aluminium-garnet (Er:YAG) laser-prepared dentine after different durations of acid etching. The occlusal third of 68 human third molars was removed in order to expose the dentine surface. The teeth were randomly divided into five groups: group B (control group), prepared with bur and total etch system with 15 s acid etching [37% orthophosphoric acid (H(3)PO(4))]; group L15, laser photo-ablated dentine (200 mJ) (laser irradiation conditions: pulse duration 100 micros, air-water spray, fluence 31.45 J/ cm(2), 10 Hz, non-contact hand pieces, beam spot size 0.9 mm, irradiation speed 3 mm/s, and total irradiation time 2 x 40 s); group L30, laser prepared, laser conditioned and 30 s acid etching; group L60, laser prepared, laser conditioned and 60 s acid etching; group L90, laser prepared, laser conditioned and 90 s acid etching. A plot of composite resin was bonded onto each exposed dentine and then tested for tensile bond strength. The values obtained were statistically analysed by analysis of variance (ANOVA) coupled with the Tukey-Kramer test at the 95% level. A 90 s acid etching before bonding showed the best bonding value (P < 0.05) when compared with all the other groups including the control group. There is no significance difference between other groups, nor within each group and the control group. There was a significant increase in tensile bond strength of the samples acid etched for 90 s.

  18. Surface Topographical Changes of a Failing Acid-Etched Long-Term in Function Retrieved Dental Implant.

    PubMed

    Monje, Alberto; González-García, Raúl; Fernández-Calderón, María Coronada; Hierro-Oliva, Margarita; González-Martín, María Luisa; Del Amo, Fernando Suarez-Lopez; Galindo-Moreno, Pablo; Wang, Hom-Lay; Monje, Florencio

    2016-02-01

    The aim of the present study was to report the main topographical and chemical changes of a failing 18-year in function retrieved acid-etching implant in the micro- and nanoscales. A partially edentulous 45 year old rehabilitated with a dental implant at 18 years of age exhibited mobility. After careful examination, a 3.25 × 13-mm press-fit dental implant was retrieved. Scanning electron microscope (SEM) analysis was carried out to study topographical changes of the retrieved implant compared with an unused implant with similar topographical characteristics. Moreover, X-ray photoelectron spectroscopy (XPS) analysis was used to study the surface composition of the retrieved failing implant. Clear changes related to the dual dioxide layer are present as visible in ≥×500 magnification. In addition, it was found that, for the retrieved implant, the surface composition consisted mainly of Ti2p, O1s, C1s, and Al2p. Also, a meaningful decrease of N and C was noticed, whereas the peaks of Ti2p, Al2p, and O1s increased when analyzing deeper (up to ×2000s) in the sample. It was shown that the superficial surface of a retrieved press-fit dual acid-etched implant 18 years after placement is impaired. However, the causes and consequences for these changes cannot be determined.

  19. Effects of rhBMP-2 on Sandblasted and Acid Etched Titanium Implant Surfaces on Bone Regeneration and Osseointegration: Spilt-Mouth Designed Pilot Study

    PubMed Central

    Kim, Nam-Ho; Lee, So-Hyoun; Ryu, Jae-Jun; Choi, Kyung-Hee; Huh, Jung-Bo

    2015-01-01

    This study was conducted to evaluate effects of rhBMP-2 applied at different concentrations to sandblasted and acid etched (SLA) implants on osseointegration and bone regeneration in a bone defect of beagle dogs as pilot study using split-mouth design. Methods. For experimental groups, SLA implants were coated with different concentrations of rhBMP-2 (0.1, 0.5, and 1 mg/mL). After assessment of surface characteristics and rhBMP-2 releasing profile, the experimental groups and untreated control groups (n = 6 in each group, two animals in each group) were placed in split-mouth designed animal models with buccal open defect. At 8 weeks after implant placement, implant stability quotients (ISQ) values were recorded and vertical bone height (VBH, mm), bone-to-implant contact ratio (BIC, %), and bone volume (BV, %) in the upper 3 mm defect areas were measured. Results. The ISQ values were highest in the 1.0 group. Mean values of VBH (mm), BIC (%), and BV (%) were greater in the 0.5 mg/mL and 1.0 mg/mL groups than those in 0.1 and control groups in buccal defect areas. Conclusion. In the open defect area surrounding the SLA implant, coating with 0.5 and 1.0 mg/mL concentrations of rhBMP-2 was more effective, compared with untreated group, in promoting bone regeneration and osseointegration. PMID:26504807

  20. Effect of fluoride on the morphology of calcium phosphate crystals grown on acid-etched human enamel.

    PubMed

    Fan, Y; Sun, Z; Moradian-Oldak, J

    2009-01-01

    The aim of this study was to examine the effect of fluoride ion concentration on the morphology of calcium phosphate crystals grown on acid-etched enamel as a model for tooth enamel erosion. Samples were immersed in calcification solution for 16 h and changes in crystal morphology were monitored by field emission scanning electron microscopy. Without fluoride, plate-like octacalcium phosphate crystals (20 nm thick, 2-10 microm wide) were formed. With 1-10 mg/l fluoride, arrays of denser needle-like nanocrystals (20-30 nm wide, >500 nm in length) were formed. We conclude that there is a minimal fluoride concentration (1 mg/l) that dramatically affects the morphology of calcium phosphate crystals grown on etched enamel in vitro.

  1. Effect of Fluoride on the Morphology of Calcium Phosphate Crystals Grown on Acid-Etched Human Enamel

    PubMed Central

    Fan, Y.; Sun, Z.; Moradian-Oldak, J.

    2009-01-01

    The aim of this study was to examine the effect of fluoride ion concentration on the morphology of calcium phosphate crystals grown on acid-etched enamel as a model for tooth enamel erosion. Samples were immersed in calcification solution for 16 h and changes in crystal morphology were monitored by field emission scanning electron microscopy. Without fluoride, plate-like octacalcium phosphate crystals (20 nm thick, 2–10 μm wide) were formed. With 1–10 mg/l fluoride, arrays of denser needle-like nanocrystals (20–30 nm wide, >500 nm in length) were formed. We conclude that there is a minimal fluoride concentration (1 mg/l) that dramatically affects the morphology of calcium phosphate crystals grown on etched enamel in vitro. PMID:19321991

  2. Changes in the surface of bone and acid-etched and sandblasted implants following implantation and removal

    PubMed Central

    Eroglu, Cennet Neslihan; Ertugrul, Abdullah Seckin; Eskitascioglu, Murat; Eskitascioglu, Gurcan

    2016-01-01

    Objective: The aim of this study was to determine whether there are any changes in the surface of bone or implant structures following the removal of a screwed dental implant. Materials and Methods: For this, six individual samples of acid-etched and sandblasted implants from three different manufacturers’ implant systems were used. They were screwed in a D1 bovine bone, and they were removed after primary stabilization. The bone and implant surfaces are evaluated with scanning electron microscope. Results: Through examination of the surfaces of the bone prior to implantation and of the used and unused implant surfaces, it was found that inhomogeneity in the implant surface can cause microcracking in the bone. Conclusions: This is attributed to the stress induced during the implantation of self-tapping implants and suggests that a tap drill may be required in some instances to protect the implant surface. PMID:27011744

  3. An In Vitro Comparison of the Bond Strength of Composite to Superficial and Deep Dentin, Treated With Er:YAG Laser Irradiation or Acid-Etching.

    PubMed

    Alaghehmand, Homayoon; Nezhad Nasrollah, Fatemeh; Nokhbatolfoghahaei, Hanieh; Fekrazad, Reza

    2016-01-01

    Introduction: The aim of this study was to compare the micro-shear bond strength of composite resin on superficial and deep dentin after conditioning with phosphoric acid and Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser. Methods: Thirty human molars were selected, roots were removed and crowns were bisected to provide a total of 60 half-crowns. Specimens were ground to expose superficial and deep dentin. Samples were assigned to six groups: (1) AS (acid etching of superficial dentin); (2) AD (acid etching of deep dentin); (3) LS (Er:YAG laser irradiation on superficial dentin); (4) LD (Er:YAG laser irradiation on deep dentin); (5) LAS (Er:YAG laser irradiation on superficial dentin followed by acid etching); (6) LAD (Er:YAG laser irradiation on deep dentin followed by acid etching) The adhesive protocol was performed. Samples were thermocycled and micro-shear bond strength was tested to failure. The data were submitted to statistical analysis with one-way analysis of variance (ANOVA) and Tukey post hoc test. Results: The AS group, demonstrated the greatest amount of micro-shear bond strength. Statistical analysis showed a decrease in bond strength in laser-treated groups which was more significant for deep dentin. Conclusion: Preparation of dentin with laser did not improve bonding to superficial and deep dentin.

  4. An In Vitro Comparison of the Bond Strength of Composite to Superficial and Deep Dentin, Treated With Er:YAG Laser Irradiation or Acid-Etching

    PubMed Central

    Alaghehmand, Homayoon; Nezhad Nasrollah, Fatemeh; Nokhbatolfoghahaei, Hanieh; Fekrazad, Reza

    2016-01-01

    Introduction: The aim of this study was to compare the micro-shear bond strength of composite resin on superficial and deep dentin after conditioning with phosphoric acid and Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser. Methods: Thirty human molars were selected, roots were removed and crowns were bisected to provide a total of 60 half-crowns. Specimens were ground to expose superficial and deep dentin. Samples were assigned to six groups: (1) AS (acid etching of superficial dentin); (2) AD (acid etching of deep dentin); (3) LS (Er:YAG laser irradiation on superficial dentin); (4) LD (Er:YAG laser irradiation on deep dentin); (5) LAS (Er:YAG laser irradiation on superficial dentin followed by acid etching); (6) LAD (Er:YAG laser irradiation on deep dentin followed by acid etching) The adhesive protocol was performed. Samples were thermocycled and micro-shear bond strength was tested to failure. The data were submitted to statistical analysis with one-way analysis of variance (ANOVA) and Tukey post hoc test. Results: The AS group, demonstrated the greatest amount of micro-shear bond strength. Statistical analysis showed a decrease in bond strength in laser-treated groups which was more significant for deep dentin. Conclusion: Preparation of dentin with laser did not improve bonding to superficial and deep dentin. PMID:28144437

  5. Comparison of shear bond strength of reattached incisor fragment using Er,Cr:YSGG laser etching and conventional acid etching: An in vitro study

    PubMed Central

    Kumar, Gyanendra; Goswami, Mridula; Dhillon, Jatinder Kaur

    2016-01-01

    Aim: The aim of this invitro study is to evaluate the shear bond strength of reattached fractured incisor fragments using Er,Cr:YSGG laser and conventional acid etching without additional tooth preparation. Materials and methods: Forty extracted human teeth were divided in two groups of 20 each (Groups A and B). In Group A, fractured surface was treated by an Er, Cr: YSGG laser system (Waterlase MD, Biolase Technology Inc., San Clemente, CA, USA) operating at a wavelength of 2,780 nm and frequency of 20 Hz. In Group B, fractured surface was etched using 37% phosphoric acid (Scotchbond, 3M). In both the groups, further subdivision with 10 sample each was made based on horizontal and oblique fracture. After laser or acid etching, all the samples were reattached using flowable composite resin and light cured. The samples were tested for shear bond strength. Results: Mean shear bond strength for Group A (94.70±39.158) was lower as compared to Group B (121.25±49.937), although the difference was not statistically significant(p value=0.121). Similarly no statistical significant difference was observed amongst the subgroups. (p>0.05) Conclusion: Er,Cr:YSGG laser etching in reattachment of fractured incisor fragment is a good alternative to conventional acid etching. Er,Cr:YSGG showed comparable efficiency in rebonding of fractured teeth fragment as acid etching. PMID:27721563

  6. 241-AN Double Shell Tanks (DST) Integrity Assessment Report

    SciTech Connect

    JENSEN, C.E.

    1999-09-21

    This report presents the results of the integrity assessment of the 241-AN double-shell tank farm facility located in the 200 East Area of the Hanford Site. The assessment included the design evaluation and integrity examinations of the tanks and concluded that the facility is adequately designed, is compatible with the waste, and is fit for use. Recommendations including subsequent examinations, are made to ensure the continued safe operation of the tanks.

  7. 241-AZ Double Shell Tanks (DST) Integrity Assessment Report

    SciTech Connect

    JENSEN, C.E.

    1999-09-21

    This report presents the results of the integrity assessment of the 241-A2 double-shell tank farm facility located in the 200 East Area of the Hanford Site. The assessment included the design evaluation and integrity examinations of the tanks and concluded that the facility is adequately designed, is compatible with the waste, and is fit for use. Recommendations including subsequent examinations, are made to ensure the continued safe operation of the tanks.

  8. Effect of acid etching on marginal adaptation of mineral trioxide aggregate to apical dentin: microcomputed tomography and scanning electron microscopy analysis.

    PubMed

    Al-Fouzan, Khalid; Al-Garawi, Ziad; Al-Hezaimi, Khalid; Javed, Fawad; Al-Shalan, Thakib; Rotstein, Ilan

    2012-12-01

    The present investigation assessed the effect of acid etching on marginal adaptation of white- and gray-colored mineral trioxide aggregate (MTA) to apical dentin using microcomputed tomography (micro-CT) and scanning electron microscopy (SEM). Sixty-four extracted single-rooted human maxillary teeth were used. Following root-end resection and apical preparation, the teeth were equally divided into four groups according to the following root end filling materials: (i) white-colored MTA (WMTA), (ii) etched WMTA (EWMTA), (iii) gray-colored MTA (GMTA) and (iv) etched GMTA (EGMTA). After 48 h, the interface between root-end filling materials and the dentinal walls was assessed using micro-CT and SEM. Data were statistically analyzed using the Kruskal-Wallis and Dunn tests. Micro-CT analysis revealed gap volumes between the apical cavity dentin walls and EGMTA, GMTA, EWMTA and WMTA of (0.007 1±0.004) mm(3), (0.053±0.002) mm(3), (0.003 6±0.001) mm(3) and (0.005 9±0.002) mm(3) respectively. SEM analysis revealed gap sizes for EGMTA, WMTA, EWMTA and GMTA to be (492.3±13.8) µm, (594.5±17.12) µm, (543.1±15.33) µm and (910.7±26.2) µm respectively. A significant difference in gap size between root end preparations filled with GMTA and EGMTA was found (P<0.05). No significance difference in gap size between WMTA and EWMTA were found in either SEM or micro-CT analysis. In conclusion, pre-etching of apical dentin can provide a better seal for GMTA but not for WMTA.

  9. Comparison of shear bond strength and surface structure between conventional acid etching and air-abrasion of human enamel.

    PubMed

    Olsen, M E; Bishara, S E; Damon, P; Jakobsen, J R

    1997-11-01

    Recently, air-abrasion technology has been examined for potential applications within dentistry, including the field of orthodontics. The purpose of this study was to compare the traditional acid-etch technique with an air-abrasion surface preparation technique, with two different sizes of abrading particles. The following parameters were evaluated: (a) shear bond strength, (b) bond failure location, and (c) enamel surface preparation, as viewed through a scanning electron microscope. Sixty extracted human third molars were pumiced and divided into three groups of 20. The first group was etched with a 37% phosphoric acid gel for 30 seconds, rinsed for 30 seconds, and dried for 20 seconds. The second and third groups were air-abraded with (a) a 50 microm particle and (b) a 90 microm particle of aluminum oxide, with the Micro-etcher microabrasion machine (Danville Engineering Inc.). All three groups had molar stainless steel orthodontic brackets bonded to the buccal surface of each tooth with Transbond XT bonding system (3M Unitek). A Zwick Universal Testing Machine (Calitek Corp.) was used to determine shear bond strengths. The analysis of variance was used to compare the three groups. The Adhesive Remnant Index (ARI) was used to evaluate the residual adhesive on the enamel after bracket removal. The chi square test was used to evaluate differences in the ARI scores among the groups. The significance for all tests was predetermined at p < or = 0.05. The results indicated that there was a significant difference in shear bond strength among the three groups (p = 0.0001). The Duncan Multiple Range test showed a significant decrease in shear bond strength in the air-abraded groups. The chi square test revealed significant differences among the ARI scores of the acid-etched group and the air-abraded groups (chi(2) = 0.0001), indicating no adhesive remained on the enamel surface after debonding when air-abrasion was used. In conclusion, the current findings indicate that

  10. The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics

    PubMed Central

    Ramakrishnaiah, Ravikumar; Alkheraif, Abdulaziz A.; Divakar, Darshan Devang; Matinlinna, Jukka P.; Vallittu, Pekka K.

    2016-01-01

    The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™); the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching) and four experimental groups (20, 40, 80 and 160 s of etching). The etched surfaces’ microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey’s test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability. PMID:27240353

  11. The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics.

    PubMed

    Ramakrishnaiah, Ravikumar; Alkheraif, Abdulaziz A; Divakar, Darshan Devang; Matinlinna, Jukka P; Vallittu, Pekka K

    2016-05-27

    The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™); the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching) and four experimental groups (20, 40, 80 and 160 s of etching). The etched surfaces' microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey's test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability.

  12. The effects of acid etching time on surface mechanical properties of dental hard tissues.

    PubMed

    Zafar, Muhammad Sohail; Ahmed, Naseer

    2015-01-01

    The objective of this study was to evaluate the effect of etching time on the surface properties of dental hard tissues including enamel and dentin. For this purpose, samples were prepared using extracted human teeth and treated with 37% phosphoric acid for various length of time using the set protocol. The effects of etching time on surface roughness were assessed using non-contact surface roughness profilometer and surface hardness was measured using nanoindentation technique. All results were analyzed statistically using SPSS computer software. Within the limitation of this study, it was concluded that etching time influences on the surface properties of dental hard tissues particularly the enamel. Enamel surface properties such as roughness and hardness can be altered remarkable as a matter of few seconds. Prolonged etching time than recommended is likely to increase the surface roughness and decrease surface hardness; compromising the bond strength of adhesive materials in clinical applications.

  13. From acid etching treatments to tribocorrosive properties of dental implants: do some experimental results on surface treatments have an influence on the tribocorrosion behaviour of dental implants?

    NASA Astrophysics Data System (ADS)

    Geringer, Jean; Demanget, Nicolas; Pellier, Julie

    2013-10-01

    Surface treatments of dental implants aim at promoting osseointegration, i.e. the anchorage of the metallic part. Titanium-, grade II-V, based material is used as a bulk material for dental implants. For promoting the anchorage of this metallic biomaterial in human jaw, some strategies have been applied for improving the surface state, i.e. roughness, topography and coatings. A case study, experimental study, is described with the method of acid etching on titanium grade 4, CpTi. The main goal is to find the right proportion in a mixture of two acids in order to obtain the best surface state. Finally, a pure theoretical prediction is quite impossible and some experimental investigations are necessary to improve the surface state. The described acid etching is compared with some other acid etching treatments and some coatings available on dental implants. Thus, the discussion is focused on the tribocorrosion behaviour of titanium-based materials. The purpose of the coating is that the lifetime under tribocorrosion is limited. Moreover, the surgery related to the implantation has a huge impact on the stability of dental implants. Thus, the performance of dental implants depends on factors related to surgery (implantation) that are difficult to predict from the biomaterial characteristics. From the tribocorrosion point of view, i.e. during the mastication step, the titanium material is submitted to some deleterious factors that cause the performance of dental implants to decrease.

  14. Effect of Lactic Acid Etching on Bonding Effectiveness of Orthodontic Bracket after Water Storage

    PubMed Central

    Alsulaimani, Fahad F.

    2014-01-01

    Objective. To determine the effect of lactic acid at various concentrations on the shear bond strength of orthodontic brackets bonded with the resin adhesive system before and after water storage. Materials and Methods. Hundred extracted human premolars were divided into 5 treatment groups and etched for 30 seconds with one of the following agents: lactic acid solution with (A) 10%, (B) 20%, (C) 30%, and (D) 50%; group E, 37% phosphoric acid (control). Metal brackets were bonded using a Transbond XT. Bonding effectiveness was assessed by shear bond strength after 24 hours and 6 months of water storage at 37°C. The data were analyzed with 2-way analysis of variance and Tukey's Honestly Significant Difference (HSD) test (α = .001). Results. Lactic acid concentration and water storage resulted in significant differences for brackets bond strength (P < .001). 20% lactic acid had significantly higher mean bond strength values (SD) for all conditions: 24 hours [12.2 (.7) MPa] and 6 months [10.1 (.6) MPa] of water storage. 37% phosphoric acid had intermediate bond strength values for all conditions: 24 hours [8.2 (.6) MPa] and 6 months [6.2 (.6) MPa] of water storage. Also, there were differences in bond strength between storage time, with a reduction in values from 24 hours and 6 months for all experimental groups (P < .001). Conclusion. Lactic acid could be used in place of phosphoric acid as an enamel etchant for bonding of orthodontic brackets. PMID:25006465

  15. Temperature Rise Induced by Light Curing Unit Can Shorten Enamel Acid-Etching Time

    PubMed Central

    Najafi Abrandabadi, Ahmad; Sheikh-Al-Eslamian, Seyedeh Mahsa; Panahandeh, Narges

    2015-01-01

    Objectives: The aim of this in-vitro study was to assess the thermal effect of light emitting diode (LED) light curing unit on the enamel etching time. Materials and Methods: Three treatment groups with 15 enamel specimens each were used in this study: G1: Fifteen seconds of etching, G2: Five seconds of etching, G3: Five seconds of etching plus LED light irradiation (simultaneously). The micro shear bond strength (μSBS) of composite resin to enamel was measured. Results: The mean μSBS values ± standard deviation were 51.28±2.35, 40.47±2.75 and 50.00±2.59 MPa in groups 1, 2 and 3, respectively. There was a significant difference between groups 1 and 2 (P=0.013) and between groups 2 and 3 (P=0.032) in this respect, while there was no difference between groups 1 and 3 (P=0.932). Conclusion: Simultaneous application of phosphoric acid gel over enamel surface and light irradiation using a LED light curing unit decreased enamel etching time to five seconds without compromising the μSBS. PMID:27559352

  16. Hazard assessments of double-shell flammable gas tanks

    SciTech Connect

    Fox, G.L.; Stepnewski, D.D.

    1994-09-28

    This report is the fourth in a series of hazard assessments performed on the double-shell flammable gas watch list tanks. This report focuses on hazards associated with the double-shell watch list tanks (101-AW, 103-AN, 104-AN, and 105-AN). While a similar assessment has already been performed for tank 103-SY, it is also included here to incorporate a more representative slurry gas mixture and provide a consistent basis for comparing results for all the flammable gas tanks. This report is intended to provide an in-depth assessment by considering the details of the gas release event and slurry gas mixing as the gas is released from the waste. The consequences of postulated gas ignition are evaluated using a plume burn model and updated ignition frequency predictions. Tank pressurization which results from a gas burn, along with the structural response, is also considered. The report is intended to support the safety basis for work activities in flammable gas tanks by showing margins to safety limits that are available in the design and procedures.

  17. Mixed matrix membranes with HF acid etched ZSM-5 for ethanol/water separation: Preparation and pervaporation performance

    NASA Astrophysics Data System (ADS)

    Zhan, Xia; Lu, Juan; Tan, Tingting; Li, Jiding

    2012-10-01

    The mixed matrix membranes (MMMs) were prepared from crosslinked PDMS incorporated with HF acid etched ZSM-5. ZSM-5 zeolite was etched with a series of HF aqueous-acetone solution and characterized by SEM, BET, XRD and FT-IR. It was found that HF etching process was very effective for removing organic impurities in zeolite and micro-pores were observed out of the surface of zeolite particles, which enhanced the hydrophobicity and surface roughness of ZSM-5 successfully. Both tensile strength and swelling resistance of ZSM-5/PDMS MMMs increased with the rising concentration of HF solution, which can mainly be attributed to the improved zeolite-PDMS interfacial adhesion resulted from the intrusion of PDMS into micro-pores out of the ZSM-5 surface. Subsequently, the sorption experiment was performed with the results suggesting preferential sorption of ethanol by MMMs. Moreover, the sorption selectivity of ZSM-5/PDMS MMMs increased notably as the concentration of HF solution increased. The pervaporation performance of ethanol/water mixtures using MMMs was also investigated in detail. The MMMs filled with etched ZSM-5 showed much better selectivity than that filled with non-etched ones, with a little expense of permeability. It was found that with the same zeolite loading, increasing the HF acid concentration in etching process enhanced the zeolite-PDMS interfacial adhesion which promoted the ethanol selectivity of MMMs, while depressed the total permeation flux a little. In addition, both ethanol permeation and the selectivity increased with an increase of the zeolite loading from 10% to 30%. Nevertheless, excessive zeolite loading or decreasing thickness of selective layer led to the poor selectivity to ethanol. A decline of the ethanol selectivity was also observed as the feed ethanol concentration as well as feed temperature increased.

  18. Comparative Evaluation of the Etching Pattern of Er,Cr:YSGG & Acid Etching on Extracted Human Teeth-An ESEM Analysis

    PubMed Central

    Mazumdar, Dibyendu; Ranjan, Shashi; Krishna, Naveen Kumar; Kole, Ravindra; Singh, Priyankar; Lakiang, Deirimika; Jayam, Chiranjeevi

    2016-01-01

    Introduction Etching of enamel and dentin surfaces increases the surface area of the substrate for better bonding of the tooth colored restorative materials. Acid etching is the most commonly used method. Recently, hard tissue lasers have been used for this purpose. Aim The aim of the present study was to evaluate and compare the etching pattern of Er,Cr:YSGG and conventional etching on extracted human enamel and dentin specimens. Materials and Methods Total 40 extracted non-diseased teeth were selected, 20 anterior and 20 posterior teeth each for enamel and dentin specimens respectively. The sectioned samples were polished by 400 grit Silicon Carbide (SiC) paper to a thickness of 1.0 ± 0.5 mm. The enamel and dentin specimens were grouped as: GrE1 & GrD1 as control specimens, GrE2 & GrD2 were acid etched and GrE3 & GrD3 were lased. Acid etching was done using Conditioner 36 (37 % phosphoric acid) according to manufacturer instructions. Laser etching was done using Er,Cr:YSGG (Erbium, Chromium : Ytrium Scandium Gallium Garnet) at power settings of 3W, air 70% and water 20%. After surface treatment with assigned agents the specimens were analyzed under ESEM (Environmental Scanning Electron Microscope) at X1000 and X5000 magnification. Results Chi Square and Student “t” statistical analysis was used to compare smear layer removal and etching patterns between GrE2-GrE3. GrD2 and GrD3 were compared for smear layer removal and diameter of dentinal tubule opening using the same statistical analysis. Chi-square test for removal of smear layer in any of the treated surfaces i.e., GrE2-E3 and GrD2-D3 did not differ significantly (p>0.05). While GrE2 showed predominantly type I etching pattern (Chi-square=2.78, 0.05

    0.10) and GrE3 showed type III etching (Chi-square=4.50, p<0.05). The tubule diameters were measured using GSA (Gesellschaft fur Softwareentwicklung und Analytik, Germany) image analyzer and the ‘t’ value of student ‘t’ test was 18.10 which was a

  19. Effect of adhesive hydrophilicity and curing-time on the permeability of resins bonded to water vs. ethanol-saturated acid-etched dentin

    PubMed Central

    Cadenaro, Milena; Breschi, Lorenzo; Rueggeberg, Frederick A.; Agee, Kelli; Di Lenarda, Roberto; Carrilho, Marcela; Tay, Franklin R.; Pashley, David H.

    2009-01-01

    Objective This study examined the ability of five comonomer blends (R1-R5) of methacrylate-based experimental dental adhesives solvated with 10 mass% ethanol, at reducing the permeability of acid-etched dentin. The resins were light-cured for 20, 40 or 60 s. The acid-etched dentin was saturated with water or 100% ethanol. Method Human unerupted third molars were converted into crown segments by removing the occlusal enamel and roots. The resulting crown segments were attached to plastic plates connected to a fluid-filled system for quantifying fluid flow across smear layer-covered dentin, acid-etched dentin and resin-bonded dentin. The degree of conversion of the resins was measured using Fourier transform infrared spectroscopy. Result Application of the most hydrophobic comonomer blend (R1) to water-saturated dentin produced the smallest reductions in dentin permeability (31.9, 44.1 and 61.1% after light-curing for 20, 40 or 60 s respectively). Application of the same blend to ethanol-saturated dentin reduced permeability of 74.1, 78.4 and 81.2%, respectively (p<0.05). Although more hydrophilic resins produced larger reductions in permeability, the same trend of significantly greater reductions in ethanol-saturated dentin over that of water-saturated dentin remained. This result can be explained by the higher solubility of resins in ethanol vs. water. Significance The largest reductions in permeability produced by resins were equivalent but not superior, to those produced by smear layers. Resin sealing of dentin remains a technique-sensitive step in bonding etch-and-rinse adhesives to dentin. PMID:18571228

  20. Evaluation of modifying the bonding protocol of a new acid-etch primer on the shear bond strength of orthodontic brackets.

    PubMed

    Ajlouni, Raed; Bishara, Samir E; Oonsombat, Charuphan; Denehy, Gerald E

    2004-06-01

    The purpose of the study was to evaluate the shear bond strength of orthodontic brackets when light curing both the self-etch primer and the adhesive in one step. Fourty eight teeth were bonded with self-etch primer Angel I (3M/ESPE, St Paul, Minn) and divided into three groups. In group I (control), 16 teeth were stored in deionized water for 24 hours before debonding. In group II, 16 teeth were debonded within half-an-hour to simulate when the initial archwires were ligated. In group III, 16 additional teeth were bonded using exactly the same procedure as in groups I and II, but the light cure used for 10 seconds after applying the acid-etch primer was eliminated, and the light cure used for 20 seconds after the precoated bracket was placed over the tooth. This saved at least two minutes of the total time of the bonding procedure. The teeth in this group were also debonded within half-an-hour from the time of initial bonding. The teeth debonded after 24 hours of water storage at 37 degrees C had a mean shear bond strength of 6.0 +/- 3.5 MPa, the group that was debonded within half-an-hour of two light exposures had a mean shear bond strength of 5.9 +/- 2.7 MPa, and the mean for the group with only one light cure exposure was 4.3 +/- 2.6 MPa. Light curing the acid-etch primer together with the adhesive after placing the orthodontic bracket did not significantly diminish the shear bond strength as compared with light curing the acid-etch primer and the adhesive separately.

  1. A comparative study of shear bond strength of orthodontic bracket after acid-etched and Er:YAG treatment on enamel surface

    NASA Astrophysics Data System (ADS)

    Leão, Juliana C.; Mota, Cláudia C. B. O.; Cassimiro-silva, Patricia F.; Gomes, Anderson S. L.

    2016-02-01

    This study aimed to evaluate the shear bond strength (SBS) of teeth prepared for orthodontic bracket bonding with 37% phosphoric acid and Er:YAG laser. Forty bovine incisors were divided into two groups. In Group I, the teeth were conditioned with 37% phosphoric acid and brackets were bonded with Transbond XT; in Group II, the teeth were irradiated with Er:YAG and bonding with Transbond XT. After SBS test, the adhesive remnant index was determined. Adhesion to dental hard tissues after Er:YAG laser etching was inferior to that obtained after acid etching but exceeded what is believed to be clinically sufficient strength, and therefore can be used in patients.

  2. Early bone response to sandblasted, dual acid-etched and H2O2/HCl treated titanium implants: an experimental study in the rabbit.

    PubMed

    He, F M; Yang, G L; Li, Y N; Wang, X X; Zhao, S F

    2009-06-01

    The aim of this study was to evaluate the influence of a roughened H(2)O(2)/HCl heat-treated titanium surface on peri-implant bone formation at an early stage in vivo. 24 Ti(6)Al(4)V alloy implants were used; half were treated by sandblasted and dual acid-etched treatments (control group), while the others were treated by sandblasted, dual acid-etched and H(2)O(2)/HCl heat treatments (test group). The morphology and roughness were analyzed by field emission SEM and atomic force microscopy. The implants were inserted into the femora of 12 adult white rabbits. After 2 and 4 weeks, femora block specimens were prepared for histological and histomorphometric analysis. SEM micrographs showed that multilevel and different sized pits were formed on both surfaces. New bone formation was observed on both implant surfaces. Test implants demonstrated a greater mean percentage of bone-implant contact as compared with controls at 2 (46.84 vs. 41.81, p=0.000) and 4 weeks (49.43 vs. 44.87, p=0.006) of healing. It is concluded that the H(2)O(2)/HCl heat-treated rough titanium surface promoted enhanced bone apposition during the early stages of new bone formation around the implant.

  3. Human dental implants with a sandblasted, acid-etched surface retrieved after 5 and 10 years: a light and scanning electron microscopy evaluation of two cases.

    PubMed

    Mangano, Carlo; Perrotti, Vittoria; Raspanti, Mario; Mangano, Francesco; Luongo, Giuseppe; Piattelli, Adriano; Iezzi, Giovanna

    2013-01-01

    The aim of the present study was a light and scanning electron microscopy (SEM) evaluation of the peri-implant tissues around sandblasted, acid-etched implants, retrieved from man, after a loading period of 5 and 10 years, respectively. Two implants (Leone Implant System) had been retrieved for a fracture of the prosthetic superstructure respectively after 5 and 10 years of loading. Both implants were stable before retrieval and had been retrieved using a 5-mm trephine bur. One implant was treated to obtain thin ground sections, while the other underwent evaluation under SEM. Compact, mature lamellar bone was present over most of the implant perimeter in close contact with the implant surface and with many remodeling areas. Under SEM, small concavities, completely filled by mineralized bone, were present on the implant surface. The present histologic results showed that these implants were well integrated over the long term, and the peri-implant bone was undergoing continuous remodeling at the interface.

  4. Histological and immunohistochemical evaluation of the peri-implant soft tissues around machined and acid-etched titanium healing abutments: a prospective randomised study.

    PubMed

    Degidi, Marco; Artese, Luciano; Piattelli, Adriano; Scarano, Antonio; Shibli, Jamil A; Piccirilli, Marcello; Perrotti, Vittoria; Iezzi, Giovanna

    2012-06-01

    A close spatial correlation has been described between the roughness of intraoral materials and the rate of bacterial colonisation. The aim of the present study in man was to conduct a comparative immunohistochemical evaluation of the inflammatory infiltrate, microvessel density, the nitric oxide synthases 1 and 3 and the vascular endothelial growth factor expression, the proliferative activity, and the B and T lymphocyte and histiocyte positivity in the peri-implant soft tissues around machined and acid-etched titanium healing caps. Ten patients participated in this study. The patients were enrolled consecutively. All patients received dental implants left to heal in a non-submerged mode. Healing caps were inserted in all implants. Half of the implants were supplied randomly with machined caps of titanium (control), while the other half were provided randomly with acid-etched titanium caps (test). After a 6-month healing period, a gingival biopsy was performed with a circular scalpel around the healing caps of both groups. The inflammatory infiltrate was mostly present in test specimens. Their extension was much larger than that of the control samples. A higher number of T and B lymphocytes were observed in test specimens. Higher values of microvessel density and a higher expression of vascular endothelial growth factor intensity were observed in the test samples. Furthermore, the Ki-67, NOS1 and NOS3 expression was significantly higher in the test specimens. All these results showed that the tissues around test healing caps underwent a higher rate of restorative processes, most probably correlated to the higher inflammation processes observed in these tissues.

  5. Shear bond strength and debonding characteristics of metal and ceramic brackets bonded with conventional acid-etch and self-etch primer systems: An in-vivo study

    PubMed Central

    Mirzakouchaki, Behnam; Sharghi, Reza; Shirazi, Samaneh; Moghimi, Mahsan; Shahrbaf, Shirin

    2016-01-01

    Background Different in-vitro studies have reported various results regarding shear bond strength (SBS) of orthodontic brackets when SEP technique is compared to conventional system. This in-vivo study was designed to compare the effect of conventional acid-etching and self-etching primer adhesive (SEP) systems on SBS and debonding characteristics of metal and ceramic orthodontic brackets. Material and Methods 120 intact first maxillary and mandibular premolars of 30 orthodontic patients were selected and bonded with metal and ceramic brackets using conventional acid-etch or self-etch primer system. The bonded brackets were incorporated into the wire during the study period to simulate the real orthodontic treatment condition. The teeth were extracted and debonded after 30 days. The SBS, debonding characteristics and adhesive remnant indices (ARI) were determined in all groups. Results The mean SBS of metal brackets was 10.63±1.42 MPa in conventional and 9.38±1.53 MPa in SEP system, (P=0.004). No statistically significant difference was noted between conventional and SEP systems in ceramic brackets. The frequency of 1, 2 and 3 ARI scores and debonding within the adhesive were the most common among all groups. No statistically significant difference was observed regarding ARI or failure mode of debonded specimens in different brackets or bonding systems. Conclusions The SBS of metal brackets bonded using conventional system was significantly higher than SEP system, although the SBS of SEP system was clinically acceptable. No significant difference was found between conventional and SEP systems used with ceramic brackets. Total SBS of metal brackets was significantly higher than ceramic brackets. Due to adequate SBS of SEP system in bonding the metal brackets, it can be used as an alternative for conventional system. Key words:Shear bond strength, Orthodontic brackets, Adhesive remnant index, self-etch. PMID:26855704

  6. Comparison of Shear Bond Strength of Orthodontic Brackets Bonded to Enamel Prepared By Er:YAG Laser and Conventional Acid-Etching

    PubMed Central

    Hosseini, M.H.; Namvar, F.; Chalipa, J.; Saber, K.; Chiniforush, N.; Sarmadi, S.; Mirhashemi, A.H.

    2012-01-01

    Introduction: The purpose of this study was to compare shear bond strength (SBS) of orthodontic brackets bonded to enamel prepared by Er:YAG laser with two different powers and conventional acid-etching. Materials and Methods: Forty-five human premolars extracted for orthodontic purposes were randomly assigned to three groups based on conditioning method: Group 1- conventional etching with 37% phosphoric acid; Group 2- irradiation with Er:YAG laser at 1 W; and Group 3- irradiation with Er:YAG laser at 1.5 W. Metal brackets were bonded on prepared enamel using a light-cured composite. All groups were subjected to thermocycling process. Then, the specimens mounted in auto-cure acryle and shear bond strength were measured using a universal testing machine with a crosshead speed of 0.5 mm per second. After debonding, the amount of resin remaining on the teeth was determined using the adhesive remnant index (ARI) scored 1 to 5. One-way analysis of variance was used to compare shear bond strengths and the Kruskal-Wallis test was performed to evaluate differences in the ARI for different etching types. Results: The mean and standard deviation of conventional acid-etch group, 1W laser group and 1.5W laser group was 3.82 ± 1.16, 6.97 ± 3.64 and 6.93 ± 4.87, respectively. Conclusion: The mean SBS obtained with an Er:YAG laser operated at 1W or 1.5W is approximately similar to that of conventional etching. However, the high variability of values in bond strength of irradiated enamel should be considered to find the appropriate parameters for applying Er:YAG laser as a favorable alternative for surface conditioning. PMID:22924098

  7. Rapid formation of AgnX(X = S, Cl, PO4, C2O4) nanotubes via an acid-etching anion exchange reaction

    NASA Astrophysics Data System (ADS)

    Li, Jingjing; Yang, Wenlong; Ning, Jiqiang; Zhong, Yijun; Hu, Yong

    2014-05-01

    This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4, and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the transformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by effectively controlling the diffusion rates of different species of reacting ions. As a demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the photodegradation of rhodamine B (RhB) under visible-light irradiation.This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4, and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the transformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by effectively controlling the diffusion rates of different species of reacting ions. As a demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the

  8. Ultrasonic recovery of copper and iron through the simultaneous utilization of Printed Circuit Boards (PCB) spent acid etching solution and PCB waste sludge.

    PubMed

    Huang, Zhiyuan; Xie, Fengchun; Ma, Yang

    2011-01-15

    A method was developed to recover the copper and iron from Printed Circuit Boards (PCB) manufacturing generated spent acid etching solution and waste sludge with ultrasonic energy at laboratory scale. It demonstrated that copper-containing PCB spent etching solution could be utilized as a leaching solution to leach copper from copper contained PCB waste sludge. It also indicated that lime could be used as an alkaline precipitating agent in this method to precipitate iron from the mixture of acidic PCB spent etching solution and waste sludge. This method provided an effective technique for the recovery of copper and iron through simultaneous use of PCB spent acid solution and waste sludge. The leaching rates of copper and iron enhanced with ultrasound energy were reached at 93.76% and 2.07% respectively and effectively separated copper from iron. Followed by applying lime to precipitate copper from the mixture of leachate and rinsing water produced by the copper and iron separation, about 99.99% and 1.29% of soluble copper and calcium were settled as the solids respectively. Furthermore the settled copper could be made as commercial rate copper. The process performance parameters studied were pH, ultrasonic power, and temperature. This method provided a simple and reliable technique to recover copper and iron from waste streams generated by PCB manufacturing, and would significantly reduce the cost of chemicals used in the recovery.

  9. Rapid formation of Ag(n)X(X = S, Cl, PO4, C2O4) nanotubes via an acid-etching anion exchange reaction.

    PubMed

    Li, Jingjing; Yang, Wenlong; Ning, Jiqiang; Zhong, Yijun; Hu, Yong

    2014-06-07

    This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4, and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the transformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by effectively controlling the diffusion rates of different species of reacting ions. As a demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the photodegradation of rhodamine B (RhB) under visible-light irradiation.

  10. Micro-shear bond strength and surface micromorphology of a feldspathic ceramic treated with different cleaning methods after hydrofluoric acid etching

    PubMed Central

    STEINHAUSER, Henrique Caballero; TURSSI, Cecília Pedroso; FRANÇA, Fabiana Mantovani Gomes; do AMARAL, Flávia Lucisano Botelho; BASTING, Roberta Tarkany

    2014-01-01

    Objective The aim of this study was to evaluate the effect of feldspathic ceramic surface cleaning on micro-shear bond strength and ceramic surface morphology. Material and Methods Forty discs of feldspathic ceramic were prepared and etched with 10% hydrofluoric acid for 2 minutes. The discs were randomly distributed into five groups (n=8): C: no treatment, S: water spray + air drying for 1 minute, US: immersion in ultrasonic bath for 5 minutes, F: etching with 37% phosphoric acid for 1 minute, followed by 1-minute rinse, F+US: etching with 37% phosphoric acid for 1 minute, 1-minute rinse and ultrasonic bath for 5 minutes. Composite cylinders were bonded to the discs following application of silane and hydrophobic adhesive for micro-shear bond strength testing in a universal testing machine at 0.5 mm/min crosshead speed until failure. Stereomicroscopy was used to classify failure type. Surface micromorphology of each treatment type was evaluated by scanning electron microscopy at 500 and 2,500 times magnification. Results One-way ANOVA test showed no significant difference between treatments (p=0.3197) and the most common failure types were cohesive resin cohesion followed by adhesive failure. Micro-shear bond strength of the feldspathic ceramic substrate to the adhesive system was not influenced by the different surface cleaning techniques. Absence of or less residue was observed after etching with hydrofluoric acid for the groups US and F+US. Conclusions Combining ceramic cleaning techniques with hydrofluoric acid etching did not affect ceramic bond strength, whereas, when cleaning was associated with ultrasound, less residue was observed. PMID:24676577

  11. Material Balance Assessment for Double-Shell Tank Waste Pipeline Transfer

    SciTech Connect

    Onishi, Yasuo; Wells, Beric E.; Hartley, Stacey A.; Enderlin, Carl W.

    2001-03-12

    PNNL developed a material balance assessment methodology based on conservation of mass for detecting leaks and mis-routings in pipeline transfer of double-shell tank waste at Hanford. The main factors causing uncertainty in these transfers are variable property and tank conditions of density, existence of crust, and surface disturbance due to mixer pump operation during the waste transfer. The methodology was applied to three waste transfers from Tanks AN-105 and AZ-102.

  12. Novel Microdilution Method to Assess Double and Triple Antibiotic Combination Therapy In Vitro.

    PubMed

    El-Azizi, Mohamed

    2016-01-01

    An in vitro microdilution method was developed to assess double and triple combinations of antibiotics. Five antibiotics including ciprofloxacin, amikacin, ceftazidime, piperacillin, and imipenem were tested against 10 clinical isolates of Pseudomonas aeruginosa. Each isolate was tested against ten double and nine triple combinations of the antibiotics. A 96-well plate was used to test three antibiotics, each one alone and in double and triple combinations against each isolate. The minimum bacteriostatic and bactericidal concentrations in combination were determined with respect to the most potent antibiotic. An Interaction Code (IC) was generated for each combination, where a numerical value was designated based on the 2-fold increase or decrease in the MICs with respect to the most potent antibiotic. The results of the combinations were verified by time-kill assay at constant concentrations of the antibiotics and in a chemostat. Only 13% of the double combinations were synergistic, whereas 5% showed antagonism. Forty-three percent of the triple combinations were synergistic with no antagonism observed, and 100% synergism was observed in combination of ciprofloxacin, amikacin, and ceftazidime. The presented protocol is simple and fast and can help the clinicians in the early selection of the effective antibiotic therapy for treatment of severe infections.

  13. Engineering Task Plan for the Integrity Assessment Examination of Double Contained Receiver Tanks (DCRT) Catch Tanks and Ancillary facilities

    SciTech Connect

    BECKER, D.L.

    2000-05-23

    This Engineering Task Plan (ETP) presents the integrity assessment examination of three DCRTs, seven catch tanks, and two ancillary facilities located in the 200 East and West Areas of the Hanford Site. The integrity assessment examinations, as described in this ETP, will provide the necessary information to enable the independently qualified registered professional engineer (IQRPE) to assess the condition and integrity of these facilities. The plan is consistent with the Double-Shell Tank Waste Transfer Facilities Integrity Assessment Plan.

  14. Performance assessment on grouted double-shell tank waste at Hanford

    SciTech Connect

    Mitchell, D.H; McNair, G.W.; Allison, J.M.

    1989-11-01

    The low-level fraction of liquid waste stored in double-shell tanks at Hanford will be solidified in a cementitious matrix (grout) and disposed in subsurface vaults. This paper discusses activities related to the preparation of a site-specific performance assessment as required by DOE Order 5820.2A. A draft performance assessment has been prepared for the planned grout disposal system at Hanford using site-specific data. The assessment estimates the incremental increase in the dose to future populations who, after loss of institutional control at the site, use groundwater downgradient of the disposal site. Increases in nonradiological species in water from a hypothetical well are also estimated. Two-dimensional transport models were used to estimate contaminant concentrations in groundwater. Based on diffusional release from the waste package, the projected radiological dose to an individual on a hypothetical farm using water from a well at the disposal facility boundary is estimated at less than one percent of the 25 mrem/yr standard in Order 5820.2. Technetium accounted for about 95% of the dose. Nitrate was the principle chemical contaminant at 0.3% to 0.5% of apportioned drinking water standards. Sensitivity studies on various parameters are in progress. This performance assessment will be updated as additional data become available.

  15. A double-mediator based whole cell electrochemical biosensor for acute biotoxicity assessment of wastewater.

    PubMed

    Gao, Guanyue; Fang, Deyu; Yu, Yuan; Wu, Liangzhuan; Wang, Yu; Zhi, Jinfang

    2017-05-15

    This work investigates the feasibility and sensitivity of a double-mediator based whole cell electrochemical biosensor to detect the acute biotoxicity of wastewater. The lipophilic mediator menadione was used to mediate the intracellular metabolic activities whereas hydrophilic potassium ferricyanide was employed as extracellular electron acceptor to transport the electron from the menadiol to anode. A chitosan hydrogel polymer film with boron-doped nanocrystalline diamond (BND) particles was electrodeposited onto a glassy carbon (GC) electrode to immobilize Saccharomyces cerevisiae cells and the mediators. The feasibility of the as-prepared biosensor was verified by determine the acute biotoxicity of four heavy metal ions(Cu(2+), Cd(2+), Ni(2+), Pb(2+)), three phenol pollutants (3,5-dichlorophenol, 4-chlorophenol, phenol) and three real wastewater samples. The IC50 values for Cu(2+), Cd(2+), Ni(2+), Pb(2+) are 10.12mg/L,13.88mg/L, 17.06mg/L and 34.56mg/L. And the IC50 value is 16.48mg/L, 34.40mg/L and 44.55mg/L for 3,5-dichlorophenol, 4-chlorophenol and phenol, respectively. The results of this work indicate that the double-mediator based whole cell electrochemical biosensor could be applied into the acute toxicity assessment of real wastewater samples with excellent performance and highlight their merit as portable and sensitive, which may providing a reasonable and reliable way for wastewater toxicity online detection.

  16. Environmental assessment for double tracks test site, Nevada Test Site, Nye County, Nevada

    SciTech Connect

    1996-04-01

    The U.S. Department of Energy, Nevada Operations Office (DOE/NV), with appropriate approvals from the U.S. Air Force (USAF), proposes to conduct environmental restoration operations at the Double Tracks test site located on the Nellis Air Force Range (NAFR) in Nye County, Nevada. This environmental assessment (EA) evaluates the potential environmental consequences of four alternative actions for conducting the restoration operation and of the no action alternative. The EA also identifies mitigation measures, where appropriate, designed to protect natural and cultural resources and reduce impacts to human health and safety. The environmental restoration operation at the Double Tracks test site would serve two primary objectives. First, the proposed work would evaluate the effectiveness of future restoration operations involving contamination over larger areas. The project would implement remediation technology options and evaluate how these technologies could be applied to the larger areas of contaminated soils on the Nevada Test Site (NTS), the Tonopah Test Range (TTR), and the NAFR. Second, the remediation would provide for the removal of plutonium contamination down to or below a predetermined level which would require cleanup of 1 hectare (ha) (2.5 acres), for the most likely case, or up to 3.0 ha (7.4 acres) of contaminated soil, for the upper bounding case.

  17. Comparison of alkaline phosphatase activity of MC3T3-E1 cells cultured on different Ti surfaces: modified sandblasted with large grit and acid-etched (MSLA), laser-treated, and laser and acid-treated Ti surfaces

    PubMed Central

    Li, Lin-Jie; Kim, So-Nam

    2016-01-01

    PURPOSE In this study, the aim of this study was to evaluate the effect of implant surface treatment on cell differentiation of osteoblast cells. For this purpose, three surfaces were compared: (1) a modified SLA (MSLA: sand-blasted with large grit, acid-etched, and immersed in 0.9% NaCl), (2) a laser treatment (LT: laser treatment) titanium surface and (3) a laser and acid-treated (LAT: laser treatment, acid-etched) titanium surface. MATERIALS AND METHODS The MSLA surfaces were considered as the control group, and LT and LAT surfaces as test groups. Alkaline phosphatase expression (ALP) was used to quantify osteoblastic differentiation of MC3T3-E1 cell. Surface roughness was evaluated by a contact profilometer (URFPAK-SV; Mitutoyo, Kawasaki, Japan) and characterized by two parameters: mean roughness (Ra) and maximum peak-to-valley height (Rt). RESULTS Scanning electron microscope revealed that MSLA (control group) surface was not as rough as LT, LAT surface (test groups). Alkaline phosphatase expression, the measure of osteoblastic differentiation, and total ALP expression by surface-adherent cells were found to be highest at 21 days for all three surfaces tested (P<.05). Furthermore, ALP expression levels of MSLA and LAT surfaces were significantly higher than expression levels of LT surface-adherent cells at 7, 14, and 21 days, respectively (P<.05). However, ALP expression levels between MSLA and LAT surface were equal at 7, 14, and 21 days (P>.05). CONCLUSION This study suggested that MSLA and LAT surfaces exhibited more favorable environment for osteoblast differentiation when compared with LT surface, the results that are important for implant surface modification studies. PMID:27350860

  18. Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Barrado, A. I.; Bettini, A.; Borges, F. I. G. M.; Camargo, M.; Cárcel, S.; Cervera, A.; Conde, C. A. N.; Conde, E.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Fernández, M.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Laing, A.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez, A.; Martínez-Lema, G.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Ortiz de Solórzano, A.; Pérez Aparicio, J. L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J. T.; Yahlali, N.

    2015-05-01

    The ``Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. Separate energy and tracking readout planes are based on different sensors: photomultiplier tubes for calorimetry and silicon multi-pixel photon counters for tracking. The design of a radiopure tracking plane, in direct contact with the gas detector medium, was specially challenging since the needed components like printed circuit boards, connectors, sensors or capacitors have typically, according to available information in databases and in the literature, activities too large for experiments requiring ultra-low background conditions. Here, the radiopurity assessment of tracking readout components based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr&aposaneo de Canfranc (Spain) is described. According to the obtained results, radiopure enough printed circuit boards made of kapton and copper, silicon photomultipliers and other required components, fulfilling the requirement of an overall background level in the region of interest of at most 8×10-4 counts keV-1 kg-1 y-1, have been identified.

  19. Asteroid Impact and Deflection Assessment mission: the Double Asteroid Redirection Test (DART)

    NASA Astrophysics Data System (ADS)

    Cheng, A.; Michel, P.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 6.5 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (i) to investigate the binary near-Earth asteroid (65803) Didymos, (ii) to demonstrate asteroid deflection by kinetic impact and to characterize the deflection. The primary DART objectives are to demonstrate a hypervelocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary.

  20. Experimental Assessment of Double Langmuir Probe Analysis Techniques in a Hall Thruster Plume

    DTIC Science & Technology

    2012-07-25

    magnitude higher than the extended far-field plume. Langmuir probes, an electrostatic diagnostic developed by Irving Langmuir in 1924 [5], are widely used...of Double Langmuir Probe Analysis Techniques in a Hall 5b. GRANT NUMBER Thruster Plume 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Brown, D.L...recent theoretical study of double Langmuir probes led to development of improved analytical techniques that account for probe electrode sheath

  1. Morphology of resin-dentin interfaces after Er,Cr:YSGG laser and acid etching preparation and application of different bonding systems.

    PubMed

    Beer, Franziska; Buchmair, Alfred; Körpert, Wolfram; Marvastian, Leila; Wernisch, Johann; Moritz, Andreas

    2012-07-01

    The goal of this study was to show the modifications in the ultrastructure of the dentin surface morphology following different surface treatments. The stability of the adhesive compound with dentin after laser preparation compared with conventional preparation using different bonding agents was evaluated. An Er,Cr:YSGG laser and 36% phosphoric acid in combination with various bonding systems were used. A total of 100 caries-free human third molars were used in this study. Immediately after surgical removal teeth were cut using a band saw and 1-mm thick dentin slices were created starting at a distance of 4 mm from the cusp plane to ensure complete removal of the enamel. The discs were polished with silicon carbide paper into rectangular shapes to a size of 6 × 4 mm (±0,2 mm).The discs as well as the remaining teeth stumps were stored in 0.9% NaCl at room temperature. The specimens were divided into three main groups (group I laser group, group II etch group, group III laser and etch group) and each group was subdivided into three subgroups which were allocated to the different bonding systems (subgroup A Excite, subgroup B Scotchbond, subgroup C Syntac). Each disc and the corresponding tooth stump were treated in the same way. After preparation the bonding composite material was applied according to the manufacturers' guidelines in a hollow tube of 2 mm diameter to the disc as well as to the corresponding tooth stump. Shear bond strength testing and environmental scanning electron microscopy were used to assess the morphology and stability of the resin-dentin interface. The self-etching bonding system showed the highest and the most constant shear values in all three main groups, thus enabling etching with phosphoric acid after laser preparation to be avoided. Thus we conclude that laser preparation creates a surface texture that allows prediction of the quality of the restoration without the risk of negative influences during the following treatment steps. This

  2. Safety and Efficacy Assessment of Two New Leprosy Skin Test Antigens: Randomized Double Blind Clinical Study

    PubMed Central

    Rivoire, Becky L.; Groathouse, Nathan A.; TerLouw, Stephen; Neupane, Kapil Dev; Ranjit, Chaman; Sapkota, Bishwa Raj; Khadge, Saraswoti; Kunwar, Chatra B.; Macdonald, Murdo; Hawksworth, Rachel; Thapa, Min B.; Hagge, Deanna A.; Tibbals, Melinda; Smith, Carol; Dube, Tina; She, Dewei; Wolff, Mark; Zhou, Eric; Makhene, Mamodikoe; Mason, Robin; Sizemore, Christine; Brennan, Patrick J.

    2014-01-01

    Background New tools are required for the diagnosis of pre-symptomatic leprosy towards further reduction of disease burden and its associated reactions. To address this need, two new skin test antigens were developed to assess safety and efficacy in human trials. Methods A Phase I safety trial was first conducted in a non-endemic region for leprosy (U.S.A.). Healthy non-exposed subjects (n = 10) received three titrated doses (2.5 µg, 1.0 µg and 0.1 µg) of MLSA-LAM (n = 5) or MLCwA (n = 5) and control antigens [Rees MLSA (1.0 µg) and saline]. A randomized double blind Phase II safety and efficacy trial followed in an endemic region for leprosy (Nepal), but involved only the 1.0 µg (high dose) and 0.1 µg (low dose) of each antigen; Tuberculin PPD served as a control antigen. This Phase II safety and efficacy trial consisted of three Stages: Stage A and B studies were an expansion of Phase I involving 10 and 90 subjects respectively, and Stage C was then conducted in two parts (high dose and low dose), each enrolling 80 participants: 20 borderline lepromatous/lepromatous (BL/LL) leprosy patients, 20 borderline tuberculoid/tuberculoid (BT/TT) leprosy patients, 20 household contacts of leprosy patients (HC), and 20 tuberculosis (TB) patients. The primary outcome measure for the skin test was delayed type hypersensitivity induration. Findings In the small Phase I safety trial, reactions were primarily against the 2.5 µg dose of both antigens and Rees control antigen, which were then excluded from subsequent studies. In the Phase II, Stage A/B ramped-up safety study, 26% of subjects (13 of 50) showed induration against the high dose of each antigen, and 4% (2 of 50) reacted to the low dose of MLSA-LAM. Phase II, Stage C safety and initial efficacy trial showed that both antigens at the low dose exhibited low sensitivity at 20% and 25% in BT/TT leprosy patients, but high specificity at 100% and 95% compared to TB patients. The high dose of both antigens

  3. Assessment of calcium dobesilate in diabetic retinopathy. A double-blind clinical investigation.

    PubMed

    Salama Benarroch, I; Nano, H; Pérez, H; Elizalde, F; Bisceglia, H; Salama, A

    1977-01-01

    In this double-blind, randomized trial, which lasted for 2 years, the authors investigated the efficacy of calcium dobesilate on diabetic retinopathy. 68 patients (51 on the active substance, 17 on placebo) participated in the study. The statistical analysis of the results indicate that calcium dobesilate acts as a potent angioprotector, capable of preventing both intra and extraretinal hemorrhages. The drug also lowers the incidence of exudate formation and improves visual acuity.

  4. [Laser treatment of sinusitis in general practice assessed by a double-blind controlled study].

    PubMed

    Moustsen, P A; Vinter, N; Aas-Andersen, L; Kragstrup, J

    1991-08-05

    The effect of Low Level Laser therapy (Galium-Aluminium-Arsenide laser, 30 mW/830 nm, Unilaser 2000 3B) on sinuitis was evaluated in a double-blind randomised clinical study comprising 60 patients from general practice. All patients received three treatments (90 seconds radiation on each sinus) with one to three days interval. No statistically significant differences in pain relief, well-being or duration of illness were observed between patients treated with laser and a placebo.

  5. Structural and Functional Assessment in Patients Treated with Systemic Isotretinoin Using Optical Coherence Tomography and Frequency-Doubling Technology Perimetry

    PubMed Central

    Bakbak, Berker; Gedik, Sansal; Koktekir, Bengu Ekinci; Guzel, Huseyin; Altınyazar, Hilmi Cevdet

    2013-01-01

    Abstract A causal association between central nervous system neuropathy and oral isotretinoin has been reported. In this study we aimed to assess retinal nerve fibre layer (RNFL) thickness and visual field changes in patients treated with systemic isotretinoin. Thirty-nine patients treated with 1 mg/kg daily oral isotretinoin were enrolled in this prospective clinical trial. All patients underwent complete ophthalmologic assessment before treatment, on day 60, and 3 months after completion of treatment. RNFL thickness measurements were performed with Stratus optical coherence tomography. Functional testing included frequency-doubling technology perimetry and Humphrey field analyser. Main outcome measures were average RNFL thicknesses and visual field indices (mean deviation, pattern standard deviation). Measurements of RNFL thickness showed no statistically significant change between the three measurements (p = 0.180). No statistically significant differences were observed in the frequency-doubling technology indices (mean deviation and pattern standard deviation, p = 0.066 and p = 0.103, respectively) and in the Humphrey field analyser indices (mean deviation and pattern standard deviation, p = 0.091 and p = 0.087, respectively) at day 60 of treatment or 3 months after the cessation of treatment. In this study of 39 patients, systemic use of isotretinoin (1 mg/kg daily) does not cause a statistically significant change in peripapillary RNFL thickness or visual field findings within the usage period, and within 3 months after cessation. PMID:28163763

  6. Optical coherence tomography assessment of a complex bifurcation lesion treated with double kissing Crush technique

    PubMed Central

    Cai, Jin-Zan; Zhang, Yao-Jun; Xu, Tian; Zhu, Yong-Xiang; Mao, Chen-Yu; Bourantas, Christos V.; Crake, Tom; Chen, Shao-Liang

    2017-01-01

    Abstract The DEFINITION (Impact of the complexity of bifurcation lesions treated with drug-eluting stents) study has provided a novel classification to evaluate the complexity of coronary bifurcation lesion according to coronary angiography, but angiographic imaging due to its low resolution and inherited limitation may result in an inaccurate adjudication. We used optical coherence tomography (OCT) to further evaluate the coronary characteristics in a patient with “simple” bifurcation lesion which was classified by the DEFINITION criteria. However, a “complex” bifurcation lesion was defined and confirmed according to the OCT results. A double kissing Crush stenting approach was adopted to treat this “complex” case finally. The immediate and long-term angiographic and OCT results were excellent. OCT may be useful imaging modality to classify complexity of coronary bifurcation lesion and subsequently guide its treatment strategy. PMID:28072714

  7. Double-shell tank integrity assessments ultrasonic test equipment performance test

    SciTech Connect

    Pfluger, D.C.

    1996-09-26

    A double-shell tank (DST) inspection (DSTI) system was performance tested over three months until August 1995 at Pittsburgh, Pennsylvania, completing a contract initiated in February 1993 to design, fabricate, and test an ultrasonic inspection system intended to provide ultrasonic test (UT) and visual data to determine the integrity of 28 DSTs at Hanford. The DSTs are approximately one-million-gallon underground radioactive-waste storage tanks. The test was performed in accordance with a procedure (Jensen 1995) that included requirements described in the contract specification (Pfluger 1995). This report documents the results of tests conducted to evaluate the performance of the DSTI system against the requirements of the contract specification. The test of the DSTI system also reflects the performance of qualified personnel and operating procedures.

  8. Accuracy assessment of single and double difference models for the single epoch GPS compass

    NASA Astrophysics Data System (ADS)

    Chen, Wantong; Qin, Honglei; Zhang, Yanzhong; Jin, Tian

    2012-02-01

    The single epoch GPS compass is an important field of study, since it is a valuable technique for the orientation estimation of vehicles and it can guarantee a total independence from carrier phase slips in practical applications. To achieve highly accurate angular estimates, the unknown integer ambiguities of the carrier phase observables need to be resolved. Past researches focus on the ambiguity resolution for single epoch; however, accuracy is another significant problem for many challenging applications. In this contribution, the accuracy is evaluated for the non-common clock scheme of the receivers and the common clock scheme of the receivers, respectively. We focus on three scenarios for either scheme: single difference model vs. double difference model, single frequency model vs. multiple frequency model and optimal linear combinations vs. traditional triple-frequency least squares. We deduce the short baseline precision for a number of different available models and analyze the difference in accuracy for those models. Compared with the single or double difference model of the non-common clock scheme, the single difference model of the common clock scheme can greatly reduce the vertical component error of baseline vector, which results in higher elevation accuracy. The least squares estimator can also reduce the error of fixed baseline vector with the aid of the multi-frequency observation, thereby improving the attitude accuracy. In essence, the "accuracy improvement" is attributed to the difference in accuracy for different models, not a real improvement for any specific model. If all noise levels of GPS triple frequency carrier phase are assumed the same in unit of cycles, it can be proved that the optimal linear combination approach is equivalent to the traditional triple-frequency least squares, no matter which scheme is utilized. Both simulations and actual experiments have been performed to verify the correctness of theoretical analysis.

  9. Radon and material radiopurity assessment for the NEXT double beta decay experiment

    SciTech Connect

    Cebrián, S.; Dafni, T.; González-Díaz, D.; Herrera, D. C.; Irastorza, I. G.; Luzón, G.; Ortiz de Solórzano, A.; Villar, J. A.; Álvarez, V.; Cárcel, S.; Cervera, A.; Díaz, J.; Ferrario, P.; Gómez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; López-March, N. [Instituto de Física Corpuscular, CSIC & Universitat de València, C and others

    2015-08-17

    The ”Neutrino Experiment with a Xenon TPC” (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in {sup 136}Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.

  10. Radon and material radiopurity assessment for the NEXT double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Barrado, A. I.; Bettini, A.; Borges, F. I. G. M.; Camargo, M.; Cárcel, S.; Cervera, A.; Conde, C. A. N.; Conde, E.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Fernández, M.; Ferrario, P.; Freitas, E. D. C.; Fernandes, L. M. P.; Gehman, V. M.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Morata, J. A. Hernando; Herrera, D. C.; Irastorza, I. G.; Laing, A.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez, A.; Martínez-Lema, G.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Vidal, J. Muñoz; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; de Solórzano, A. Ortiz; Aparicio, J. L. Pérez; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J. T.; Yahlali, N.

    2015-08-01

    The "Neutrino Experiment with a Xenon TPC" (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.

  11. Double Standards: When an Undergraduate Dissertation Becomes the Object of Two Different Assessment Approaches

    ERIC Educational Resources Information Center

    Starr-Glass, David; Ali, Tanweer

    2012-01-01

    Within a transnational educational programme, students residing in the Czech Republic obtain baccalaureate degrees from an accredited American college. The college has a distinctive approach towards learning, co-creation of knowledge and the use of mentors. Part of the degree assessment is an undergraduate dissertation, which serves as a capstone…

  12. Double-blind, randomized, pilot study assessing the resolution of postburn pruritus.

    PubMed

    Nedelec, Bernadette; Rachelska, Grazyna; Parnell, Laura K S; LaSalle, Leo

    2012-01-01

    The objective of this study was to evaluate whether Provase®, a nonprescription moisturizer with a blend of protease enzymes, would reduce postburn itching in adult burn survivors relative to a control moisturizer. This was a prospective, single-center, double-blinded, pilot study where 23 burn survivors were randomized to either the treatment group, who applied Provase, or the control group, who applied the base moisturizer used in Provase every 8 hours for 4 weeks. Twelve were randomized to the treatment and 11 to the control groups with 9 participants in each group completing the study. There was no difference between groups with respect to gender, ethnicity, causative factor, TBSA burned, or time postinjury. Participant's pruritus and scar were reevaluated on a weekly basis for 4 consecutive weeks. Relative to baseline, there was a significant reduction of itch duration in minutes at weeks 3 and 4, the number of days per week that itch was experienced at weeks 2, 3, and 4, and the number of itch episodes per day at week 2 for the treatment group. The itch TBSA reduced significantly relative to baseline for the treatment group at week 1, 2, and 3. The affective itch characteristics were significantly reduced for the treatment group for bothersome at weeks 1, 2, 3, and 4; for annoying at week 4; and for unbearable at weeks 2, 3, and 4. Although this was a pilot study and not powered for statistical differences, there were statistically significant differences for itch duration, weekly frequency, itch episodes per day, itch TBSA, and reported affective burden of itch after treatment. Further investigation is recommended with a larger sample size treated for a longer period of time where participants are stratified based on acute or chronic itch.

  13. Being overburdened and medically underserved: assessment of this double disparity for populations in the state of Maryland

    PubMed Central

    2014-01-01

    Background Environmental justice research has shown that many communities of color and low-income persons are differentially burdened by noxious land uses including Toxic Release Inventory (TRI) facilities. However, limited work has been performed to assess how these populations tend to be both overburdened and medically underserved. We explored this “double disparity” for the first time in Maryland. Methods We assessed spatial disparities in the distribution of TRI facilities in Maryland across varying levels of sociodemographic composition using 2010 US Census Health Professional Shortage Area (HPSA) data. Univariate and multivariate regression in addition to geographic information systems (GIS) were used to examine relationships between sociodemographic measures and location of TRI facilities. Buffer analysis was also used to assess spatial disparities. Four buffer categories included: 1) census tracts hosting one or more TRI facilities; 2) tracts located more than 0 and up to 0.5 km from the closest TRI facility; 3) tracts located more than 0.5 km and up to 1 km from a TRI facility; and 4) tracts located more than 1 km and up to 5 km from a TRI facility. Results We found that tracts with higher proportions of non-white residents and people living in poverty were more likely to be closer to TRI facilities. A significant increase in income was observed with an increase in distance between a census tract and the closest TRI facility. In general, percent non-white was higher in HPSA tracts that host at least one TRI facility than in non-HPSA tracts that host at least one TRI facility. Additionally, percent poverty, unemployment, less than high school education, and homes built pre-1950 were higher in HPSA tracts hosting TRI facilities than in non-HPSA tracts hosting TRI facilities. Conclusions We found that people of color and low-income groups are differentially burdened by TRI facilities in Maryland. We also found that both low-income groups and persons

  14. Comparison of single- and double-assessor scoring designs for the assessment of accomplished teaching.

    PubMed

    Engelhard, George; Myford, Carol M

    2009-01-01

    This article is based on a more extensive research report (Engelhard, Myford and Cline, 2000) prepared for the National Board for Professional Teaching Standards (NBPTS) concerning the Early Childhood/Generalist and Middle Childhood/Generalist assessment systems. The report is available from the Educational Testing Service (ETS). An earlier version of the article was presented at the American Educational Research Association Conference in New Orleans in 2000. We would like to acknowledge the helpful advice of Mike Linacre regarding the use of the FACETS computer program and the assistance of Fred Cline in analyzing these data. The material contained in this article is based on work supported by the NBPTS. Any opinions, findings, conclusions, and recommendations expressed herein are those of the authors and do not necessarily reflect the views of the NBPTS, Emory University, ETS, or the University of Illinois at Chicago.

  15. [A double blind randomised clinical trial to assess the efficacy of the treatments of the superficial pressure sores].

    PubMed

    Di Giulio, Paola; Saiani, Luisa; Laquintana, Dario; Palese, Alvisa; Perli, Serena; Andreatta, Mariarosa; Rosa, Federica; Chini, Patrizia; Soraperra, Francesca; Ventura, Ida; Suriani, Cinzia; Romani, Silvia; Zancarli, Miriam; Martini, Marta; Partel, Francesca; Bassetti, Serena; Kaisermann, Rita; Bortolotti, Chiara; Gianordoli, Mirta; Rizzoli, Ilaria; Nardelli, Roberta; Pellizzari, Enrico; Valduga, Edda; Castaman, Marta; Pordenon, Marta; Beltrame, Moira; Bertolo, Cecilia; Casasola, Eleonora; Del Pin, Patrizia; Giolo, Simonetta; Marcatti, Emanuele; Pecini, Dina; Rodaro, Marisa; Zanon, Cristina; Stefanon, Laura; Covre, Lidia; Babbo, Consuela; Martin, Irma; Roilo, Antonia; Zanutel, Marta; Sabbadin, Silvano; Boin, Laura; Caron, Alessia; Martignago, Egidio; Venturin, Valter; Greggio, Annalisa; Frigo, Paola; Lazzaron, Daniela; Tonietto, Annalisa; Zanin, Barbara; Zorzi, Silvano; Zuanon, Antonio; Salmaso, Daniele; Frison, Tiziana; Marin, Irene; Buosi, Antonella; Fiorese, Elena; Gasparin, Dino; Goat, Barbara; Saccardo, Graziella; Simonetto, Ornella; Gomiero, Silvio; Baccara, Nicoletta; Ghirardello, Lucia; Niolu, Marilena; Silvestri, Sabrina; Buffon, Maria Luisa; Casson, Paola; Santantonio, Rosy; Albore, Piersandro; Mazzorana, Elvira; Terziariol, Laura; Bulgarelli, Giuliana; Barani, Elisa; Gasparini, Patrizia; Migliori, Salvina; Sasso, Elisa; Marfisi, Rosa Maria; Tognoni, Gianni; Sgaroni, Guya; Noro, Gabriele; Mattiuzzo, Mara

    2004-01-01

    In spite of the progresses of knowledge and care, pressure sores continue to be a clinically relevant problem. A double blind randomised controlled trial was organised to assess the efficacy of triticum vulgaris (Fitostimoline) vs placebo in the re-epithelisation of superficial pressure sores. Patients with stage NPUAP II or superficial pressure sores, with an expected survival of more than 3 months and eligible for a follow-up up to 8 weeks were included, over a period of 2 years in 46 clinical sites. The protocol was approved by local ethical committees and informed consent was obtained before randomisation. Medications were performed by nurses if the patient was hospitalised and by nurses or properly instructed caregivers at home. Weekly follow-up controls were assumed by nurses. Out of the 294 randomised patients 270 were included in the analyses. The two groups are comparable for the main characteristics except for Norton Scale mean values, less severe in the group assigned to active treatment (10.1+/-3.7 vs 8.9+/-3.2). The mean follow-up was of 3.8 and 4.2 weeks with a mean duration of 26+/-18 and 29+/-18 days for the experimental group and controls respectively. Seventy-six patients in the treatment group and controls (58.0 and 54.7) had their lesions re-epithelized. Adjusting results for age, initial Norton and Push scores there are no differences between treated and controls (OR 0.99 95% IC 0.60-1.67). This multicentre study, sponsored by a research group of nurses, failed to support the hypothesis that triticum vulgaris, the active component of the product Fitostimoline, given on top of recommended treatment, provides a specific therapeutic advantage in terms of frequency and timing of re-epithelization in superficial pressure sores.

  16. Prevalence of the "double-line" sign when performing focused assessment with sonography in trauma (FAST) examinations.

    PubMed

    Patwa, Amy Shah; Cipot, Steven; Lomibao, Alvin; Nelson, Mathew; Bramante, Robert; Modayil, Veena; Haines, Christine; Ash, Adam; Raio, Christopher

    2015-09-01

    The double-line sign (DLS) is a wedge-shaped hypoechoic area in Morison's pouch bounded on both sides by echogenic lines. It represents a false-positive finding for free intraperitoneal fluid when performing focused assessment with sonography in trauma examinations. The purpose of this study was to determine the prevalence of DLS. Secondarily, the study will further investigate the relationship between the presence of a DLS and body mass index (BMI). This was a prospective study that enrolled patients over a 7-month period. Inclusion criteria were patients ≥ 18 years of age presenting to the Emergency Department (ED) requiring a FAST examination as part of the patient's standard medical care. Each examination was performed by one of six experienced ultrasonographers. Presence or absence of the DLS was established in real time and gender, height, weight, and BMI were recorded for each patient. The overall prevalence rate of DLS and the corresponding 95 % confidence interval were calculated, as well as the prevalence rates broken down by BMI characterized as underweight, normal weight, overweight, and obese; and age category (18-29, 30-64, and 65+). The Chi-square test and a Fisher's exact test for BMI category were used to compare the prevalence rates of positive DLS among the different demographic groups. 100 patients were enrolled in the study; the overall prevalence was 27 %. There was no statistical significance among the different demographic groups or BMI. The DLS is a prevalent finding. We believe this sign has become more apparent due to improved imaging technology and resolution.

  17. Low-Frequency Fatigue Assessed as Double to Single Twitch Ratio after Two Bouts of Eccentric Exercise of the Elbow Flexors.

    PubMed

    Janecki, Damian; Jaskólska, Anna; Marusiak, Jarosław; Jaskólski, Artur

    2016-12-01

    The aim of this study was to assess low-frequency fatigue as a double to single twitch ratio after repeated eccentric exercise of the elbow flexors. Maximal isometric torque, single and double twitch responses and low-frequency fatigue were assessed on the elbow flexors in 16 untrained male volunteers before, immediately after, 24 and 48 hours following two bouts of eccentric exercise consisted of 30 repetitions of lowering a dumbbell adjusted to ~75% of each individual's maximal isometric torque. Maximal isometric torque and electrically evoked responses decreased significantly in all measurements after the first bout of eccentric exercise (p < 0.05). In measurements performed at 24 and 48 hours after the second bout both maximal voluntary isometric torque and electrically evoked contractions were significantly higher than in measurements performed after the first bout (p < 0.05). Although low-frequency fatigue significantly increased up to 48 hours after each bout of eccentric exercise, its values at 24 and 48 hours after the second bout were significantly lower than at respective time points after the first bout (p < 0.05). Double to single twitch ratio could be used as a sensitive tool in the evaluation of muscle recovery and adaptation to repeated eccentric exercise.

  18. Low-Frequency Fatigue Assessed as Double to Single Twitch Ratio after Two Bouts of Eccentric Exercise of the Elbow Flexors

    PubMed Central

    Janecki, Damian; Jaskólska, Anna; Marusiak, Jarosław; Jaskólski, Artur

    2016-01-01

    The aim of this study was to assess low-frequency fatigue as a double to single twitch ratio after repeated eccentric exercise of the elbow flexors. Maximal isometric torque, single and double twitch responses and low-frequency fatigue were assessed on the elbow flexors in 16 untrained male volunteers before, immediately after, 24 and 48 hours following two bouts of eccentric exercise consisted of 30 repetitions of lowering a dumbbell adjusted to ~75% of each individual’s maximal isometric torque. Maximal isometric torque and electrically evoked responses decreased significantly in all measurements after the first bout of eccentric exercise (p < 0.05). In measurements performed at 24 and 48 hours after the second bout both maximal voluntary isometric torque and electrically evoked contractions were significantly higher than in measurements performed after the first bout (p < 0.05). Although low-frequency fatigue significantly increased up to 48 hours after each bout of eccentric exercise, its values at 24 and 48 hours after the second bout were significantly lower than at respective time points after the first bout (p < 0.05). Double to single twitch ratio could be used as a sensitive tool in the evaluation of muscle recovery and adaptation to repeated eccentric exercise. Key points First bout of eccentric (ECC) exercise of the elbow flexors muscles induced repeated bout effect that lead to faster recovery of the low-frequency fatigue, the maximal torque of voluntary and electrically evoked contractions, and smaller soreness sensation, when the exercise are repeated 2-3 weeks later. Double (DT) to single twitch (ST) ratio could be used as a sensitive tool in the evaluation of muscle recovery and adaptation to repeated eccentric exercise. The single twitch and DT to ST ratios seem to be more susceptible for minimal force deficits that could occur even after repeated ECC where repeated bout effect should confer the protection after subsequent muscle damage. PMID

  19. A milestone in the doubled haploid pathway of cassava: a milestone in the doubled haploid pathway of cassava (Manihot esculenta Crantz): cellular and molecular assessment of anther-derived structures.

    PubMed

    Perera, P I P; Ordoñez, C A; Lopez-Lavalle, L A Becerra; Dedicova, B

    2014-01-01

    This study was aimed at inducing androgenesis in cultured anthers of cassava (Manihot esculenta Crantz) to develop a protocol for the production of doubled haploids. Microspore reprogramming was induced in cassava by cold or heat stress of anthers. Since the anthers contain both haploid microspores and diploid somatic cells, it was essential to verify the origin of anther-derived calli. The origin of anther-derived calli was assessed by morphological screening followed by histological analysis and flow cytometry (FCM). Additionally, simple sequence repeat (SSR) and amplified fragmented length polymorphism (AFLP) assays were used for the molecular identification of the microspore-derived calli. The study clearly demonstrated the feasibility of producing microspore-derived calli using heat- or cold-pretreated anthers. Histological studies revealed reprogramming of the developmental pathway of microspores by symmetrical division of the nucleus. Flow cytometry analysis revealed different ploidy level cell types including haploids, which confirmed their origin from the microspores. The SSR and AFLP marker assays independently confirmed the histological and FCM results of a haploid origin of the calli at the DNA level. The presence of multicellular microspores in the in vitro system indicated a switch of developmental program, which constitutes a crucial step in the design of protocols for the regeneration of microspore-derived embryos and plants. This is the first detailed report of calli, embryos, and abnormal shoots originated from the haploid cells in cassava, leading to the development of a protocol for the production of doubled haploid plants in cassava.

  20. National Water-Quality Assessment Program; summary of pesticide data collected on East Fork Double Bayou, near Anahuac, Texas, March to September 1994

    USGS Publications Warehouse

    ,

    1995-01-01

    The Trinity River Basin study-unit assessment began in October 1991, with 2 years dedicated to planning, analyzing existing information, and designing data-collection networks, surveys, and studies. Then, a 3-year intensive data-collection program was initiated. The assessment followed guidelines provided by the National Water-Quality Assessment (NAWQA) Program National Synthesis team and considered suggestions made by the study unit's liaison committee. One of the issues selected for study concerned the quality of runoff in the coastal prairie. The study includes collecting streamflow, water-quality and watershed data on three streams, each representing watersheds in different parts of the coastal prairie. This fact sheet presents a summary of the pesticide data collected on East Fork Double Bayou from March to September 1994.

  1. Double-Staining Epifluorescence Technique to Assess Frequency of Dividing Cells and Bacteriovory in Natural Populations of Heterotrophic Microprotozoa †

    PubMed Central

    Sherr, Evelyn B.; Sherr, Barry F.

    1983-01-01

    We have developed a double-staining procedure for use with epifluorescence microscopy which allows the detection both of dividing cells and of ingested bacteria in food vacuoles of heterotrophic microprotozoa. Microprotozoan cells are stained sequentially with the DNA-specific fluorochrome DAPI (4′,6-diami-dino-2-phenylindole) and the nonspecific protein stain fluorescein isothiocyanate. During microscopic examination, heterotrophic microprotozoan cells are first located with fluorescein isothiocyanate fluorescence and then epifluorescence filter sets are switched to permit inspection under DAPI fluorescence of the cell nuclei and of the contents of food vacuoles. Among in situ populations of estuarine microprotozoa sampled over a tidal cycle, we found from 2.2 to 5.2% of the heterotrophic cells in a recognizable stage of division (nuclei elongated or double). Batch culture growth experiments were also carried out both with natural populations and with two isolated species of estuarine microprotozoa. In these experiments, the frequency of dividing cells ranged from 1.2 to 3.8% and appeared to be negatively correlated with growth rate. Microprotozoan populations sampled in continental shelf waters off Savannah, Ga., had mean frequencies of dividing cells ranging from 2.0 to 5.0%. A large fraction of cells in heterotrophic microprotozoan populations (an average of 27.4 ± 1.0% in estuarine water and of 30.1 ± 4.8% in shelf water) had DAPI-stained inclusions, presumably recently ingested bacteria, in their food vacuoles. Images PMID:16346446

  2. Assessment of DNA double-strand breaks induced by intravascular iodinated contrast media following in vitro irradiation and in vivo, during paediatric cardiac catheterization.

    PubMed

    Gould, Richard; McFadden, Sonyia L; Horn, Simon; Prise, Kevin M; Doyle, Philip; Hughes, Ciara M

    2016-01-01

    Paediatric cardiac catheterizations may result in the administration of substantial amounts of iodinated contrast media and ionizing radiation. The aim of this work was to investigate the effect of iodinated contrast media in combination with in vitro and in vivo X-ray radiation on lymphocyte DNA. Six concentrations of iodine (15, 17.5, 30, 35, 45, and 52.5 mg of iodine per mL blood) represented volumes of iodinated contrast media used in the clinical setting. Blood obtained from healthy volunteers was mixed with iodinated contrast media and exposed to radiation doses commonly used in paediatric cardiac catheterizations (0 mGy, 70 mGy, 140 mGy, 250 mGy and 450 mGy). Control samples contained no iodine. For in vivo experimentation, pre and post blood samples were collected from children undergoing cardiac catheterization, receiving iodine concentrations of up to 51 mg of iodine per mL blood and radiation doses of up to 400 mGy. Fluorescence microscopy was performed to assess γH2AX-foci induction, which corresponded to the number of DNA double-strand breaks. The presence of iodine in vitro resulted in significant increases of DNA double-strand breaks beyond that induced by radiation for ≥ 17.5 mg/mL iodine to blood. The in vivo effects of contrast media on children undergoing cardiac catheterization resulted in a 19% increase in DNA double-strand breaks in children receiving an average concentration of 19 mg/mL iodine to blood. A larger investigation is required to provide further information of the potential benefit of lowering the amount of iodinated contrast media received during X-ray radiation investigations.

  3. Adaptation of the neutral bacterial comet assay to assess antimicrobial-mediated DNA double-strand breaks in Escherichia coli

    PubMed Central

    SOLANKY, DIPESH; HAYDEL, SHELLEY E.

    2012-01-01

    This study aimed to determine the mechanism of action of a natural antibacterial clay mineral mixture, designated CB, by investigating the induction of DNA double-strand breaks (DSBs) in Escherichia coli. To quantify DNA damage upon exposure to soluble antimicrobial compounds, we modified a bacterial neutral comet assay, which primarily associates the general length of an electrophoresed chromosome, or comet, with the degree of DSB-associated DNA damage. To appropriately account for antimicrobial-mediated strand fragmentation, suitable control reactions consisting of exposures to water, ethanol, kanamycin, and bleomycin were developed and optimized for the assay. Bacterial exposure to the CB clay resulted in significantly longer comet lengths, compared to water and kanamycin exposures, suggesting that the induction of DNA DSBs contributes to the killing activity of this antibacterial clay mineral mixture. The comet assay protocol described herein provides a general technique for evaluating soluble antimicrobial-derived DNA damage and for comparing DNA fragmentation between experimental and control assays. PMID:22940101

  4. Carbon nanotube ecotoxicity in amphibians: assessment of multiwalled carbon nanotubes and comparison with double-walled carbon nanotubes.

    PubMed

    Mouchet, Florence; Landois, Perine; Puech, Pascal; Pinelli, Eric; Flahaut, Emmanuel; Gauthier, Laury

    2010-08-01

    The potential impact of industrial multiwalled carbon nanotubes (MWNTs) was investigated under normalized laboratory conditions according to the International Standard micronucleus assay ISO 21427-1 for 12 days of half-static exposure to 0.1, 1, 10 and 50 mg/l of MWNTs in water. Three different end points were carried out for 12 days of exposure: mortality, growth inhibition and micronuclei induction in erythrocytes of the circulating blood of larvae. Raman spectroscopy analysis was used to study the presence of carbon nanotubes in the biological samples. Considering the high diversity of carbon nanotubes according to their different characteristics, MWNTs were analyzed in Xenopus larvae, comparatively to double-walled carbon nanotubes used in a previous study in similar conditions. Growth inhibition in larvae exposed to 50 mg/l of MWNTs was evidenced; however, no genetoxicity (micronucleus assay) was noticed, at any concentration. Carbon nanotube localization in the larvae leads to different possible hypothesis of mechanisms explaining toxicity in Xenopus.

  5. Weathering the Double Whammy.

    ERIC Educational Resources Information Center

    Wellman, Jane V.

    2002-01-01

    Discusses how governing boards can help their institutions weather the "double-whammy" of doing more with less: identify the institution's short-term and long-term challenges; refocus the institution's mission, planning, and programming; assess and integrate the institution's tuition, aid, and outreach strategies; redouble the…

  6. Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

    SciTech Connect

    Amendt, P; Cerjan, C; Hamza, A; Hinkel, D; Milovich, J L; Robey, H F

    2006-10-26

    The goal of demonstrating ignition on the National Ignition Facility (NIF) has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include non-cryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma mediated laser backscatter, low threshold ignition temperatures ({approx} 4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT ({approx} 790 atm) in the inner shell, strict concentricity requirements on the two shells (< 3 {micro}m), development of nano-porous (<100 nm) low-density (<100 mg/cc) metallic foams for structural support of the inner shell and hydrodynamic instability mitigation, and effective control of hydrodynamic instabilities on the high-Atwood number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition designs and required materials-science advances at the nanoscale are described herein. Two new ignition designs that use rugby-shaped vacuum hohlraums are presented which utilize either 1 MJ or 2 MJ of laser energy at 3{omega}. The capability of the NIF to generate the requested reverse-ramp pulse shape for DS ignition is expected to be comparable to the planned high-contrast ({approx}100) pulse-shape at 1.8 MJ for the baseline cryogenic target. Nano-crystalline, high-strength, Au-Cu alloy inner shells are under development using electrochemical deposition over a glass mandrel, exhibiting tensile strengths well in excess of 790 atm. Novel, low-density (85 mg/cc) copper foams have recently been demonstrated using 10 mg/cc SiO{sub 2} nano-porous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nano-materials science developments and the

  7. Immunogenicity and safety assessment of a trivalent, inactivated split influenza vaccine in Korean children: Double-blind, randomized, active-controlled multicenter phase III clinical trial.

    PubMed

    Han, Seung Beom; Rhim, Jung-Woo; Shin, Hye Jo; Lee, Soo Young; Kim, Hyun-Hee; Kim, Jong-Hyun; Lee, Kyung-Yil; Ma, Sang Hyuk; Park, Joon Soo; Kim, Hwang Min; Kim, Chun Soo; Kim, Dong Ho; Choi, Young Youn; Cha, Sung-Ho; Hong, Young Jin; Kang, Jin Han

    2015-01-01

    A multicenter, double-blind, randomized, active-control phase III clinical trial was performed to assess the immunogenicity and safety of a trivalent, inactivated split influenza vaccine. Korean children between the ages of 6 months and 18 y were enrolled and randomized into a study (study vaccine) or a control vaccine group (commercially available trivalent, inactivated split influenza vaccine) in a 5:1 ratio. Antibody responses were determined using hemagglutination inhibition assay, and post-vaccination immunogenicity was assessed based on seroconversion and seroprotection rates. For safety assessment, solicited local and systemic adverse events up to 28 d after vaccination and unsolicited adverse events up to 6 months after vaccination were evaluated. Immunogenicity was assessed in 337 and 68 children of the study and control groups. In the study vaccine group, seroconversion rates against influenza A/H1N1, A/H3N2, and B strains were 62.0% (95% CI: 56.8-67.2), 53.4% (95% CI: 48.1-58.7), and 54.9% (95% CI: 48.1-60.2), respectively. The corresponding seroprotection rates were 95.0% (95% CI: 92.6-97.3), 93.8% (95% CI: 91.2-96.4), and 95.3% (95% CI: 93.0-97.5). The lower 95% CI limits of the seroconversion and seroprotection rates were over 40% and 70%, respectively, against all strains. Seroconversion and seroprotection rates were not significantly different between the study and control vaccine groups. Furthermore, the frequencies of adverse events were not significantly different between the 2 vaccine groups, and no serious vaccination-related adverse events were noted. In conclusion, the study vaccine exhibited substantial immunogenicity and safety in Korean children and is expected to be clinically effective.

  8. Can physiologic assessment and side effects tease out differences in PTSD trials? A double-blind comparison of citalopram, sertraline, and placebo.

    PubMed

    Tucker, Phebe; Potter-Kimball, Robin; Wyatt, Dorothy B; Parker, Don E; Burgin, Christie; Jones, Dan E; Masters, Barbara K

    2003-01-01

    Effects of double-blind treatment of chronic posttraumatic stress disorder (PTSD) with 2 SSRIs and placebo on emotional symptoms and autonomic reactivity were assessed prospectively. PTSD subjects received citalopram (n=25), sertraline (n=23), or placebo (n=10) for 10 weeks, with psychophysiologic assessments performed before and after treatment. Intent-to-treat analysis showed that all treatment groups improved significantly in total symptoms of PTSD (as measured by the Clinician Administered PTSD Scale), all 3 PTSD symptom clusters, and sleep time. However, subtle differences in improvements in PTSD symptom clusters, physiologic reactivity, and reported adverse events were identified. Citalopram treated subjects significantly lowered systolic and diastolic blood pressures, while sertraline and placebo treated patients significantly lowered only systolic blood pressure reactivity to individualized trauma scripts. The sertraline group showed significantly more improvement in avoidance/numbing symptoms than both other groups. Considering side effects, subjects on sertraline reported more gastrointestinal problems, with early terminators having more insomnia. Early terminators on citalopram reported more fatigue and appetite changes than other treatment groups, with completers reporting more sexual dysfunction. Results support a class effect of SSRIs in treating PTSD symptoms, but suggest a possible differential effect of drugs on symptom clusters, physiologic parameters, and side effects that may have clinical relevance. Implications of symptom reduction noted in the smaller placebo group are discussed relative to recent concerns about increasing placebo response in clinical trials.

  9. Testosterone replacement therapy in older male subjective memory complainers: double-blind randomized crossover placebo-controlled clinical trial of physiological assessment and safety.

    PubMed

    Asih, Prita R; Wahjoepramono, Eka J; Aniwiyanti, Vilia; Wijaya, Linda K; de Ruyck, Karl; Taddei, Kevin; Fuller, Stephanie J; Sohrabi, Hamid; Dhaliwal, Satvinder S; Verdile, Giuseppe; Carruthers, Malcolm; Martins, Ralph N

    2015-01-01

    Testosterone replacement therapy (TRT) has been investigated in older men as a preventative treatment against Alzheimer's disease and dementia. However, previous studies have been contradictory. We assessed TRT physiological effects in 44 older men (aged 61 ± 7.7 years) with subjective memory complaints using a double blind, randomized, crossover, placebo-controlled study. Participants were randomized into 2 groups, one group received transdermal testosterone (50 mg) daily for 24 weeks, followed by a 4 week wash-out period, then 24 weeks of placebo; the other group received the reverse treatment. Blood evaluation revealed significant increases in total testosterone, free (calculated) testosterone, dihydrotestosterone, and a decrease in luteinizing hormone levels (p<0.001) following TRT. Although there were significant increases in red blood cell counts, hemoglobin and prostate specific antigen levels following TRT, they remained within normal ranges. No significant differences in plasma amyloid beta, estradiol, sex hormone binding globulin, insulin levels, body fat percentage, or body mass index were detected. This is the first carefully controlled study that has investigated the influence of TRT in Indonesian men on blood biomarkers linked to dementia risk. Our study suggests TRT is safe and well-tolerated in this Indonesian cohort, yet longitudinal studies with larger cohorts are needed to assess TRT further, and to establish whether TRT reduces dementia risk.

  10. Double-blind, Placebo-controlled Study Assessing the Effect of Chocolate Consumption in Subjects with a History of Acne Vulgaris

    PubMed Central

    Caperton, Caroline; Block, Samantha; Viera, Martha; Keri, Jonette

    2014-01-01

    Objective: To assess the effect of chocolate on acne exacerbation in males between the ages of 18 and 35 with a history of acne vulgaris. Design: Double-blind, placebo-controlled, randomized, controlled trial. Setting: Single-site, outpatient, research, clinical facility at an academic research institution. Participants: Fourteen men between the ages of 18 and 35 were assigned to swallow capsules filled with either unsweetened 100-percent cocoa, hydrolyzed gelatin powder, or a combination of the two, at baseline. Measurements: Lesions were assessed and photographs were taken at baseline, Day 4, and Day 7. Results: Of the 14 subjects, 13 completed this Institutional Review Board approved study. A statistically significant increase in the mean number of total acneiform lesions (comedones, papules, pustules, nodules) was detected on both Day 4 (p=0.006) and Day 7 (p=0.043) compared to baseline. A small-strength positive Pearson’s correlation coefficient existed between the amount of chocolate each subject consumed and the number of lesions each subject developed between baseline and Day 4 (r=0.250), while a medium-strength positive correlation existed between baseline and Day 7 (r=0.314). No serious adverse events occurred. Conclusion: It appears that in acne-prone, male individuals, the consumption of chocolate correlates to an increase in the exacerbation of acne. PMID:24847404

  11. A double-blind, randomized controlled, prospective trial assessing the effectiveness of oral corticoids in the treatment of symptomatic lumbar canal stenosis

    PubMed Central

    2014-01-01

    Background Corticoids have potent anti-inflammatory effects, which may help in relieving pain and dysfunction associated with lumbar canal stenosis. We assessed the effectiveness of a decreasing-dose regimen of oral corticoids in the treatment of lumbar canal stenosis in a prospective, double-blind, randomized, placebo-controlled trial. Results Sixty-one patients with lumbar canal stenosis (50–75 years; canal area < 100 mm2 at L3/L4, L4/L5, and/or L5/S1on magnetic resonance imaging; and claudication within 100 m were electronically randomized to an oral corticoid group (n = 31) or a placebo group (n = 30). The treatment group received 1 mg/kg of oral corticoids daily, with a dose reduction of one-third per week for 3 weeks. Patients and controls were assessed by the Short Form 36 Health Survey, Roland–Morris Questionnaire, 6-min walk test, visual analog scale, and a Likert scale. All instruments showed similar outcomes for the corticoid and placebo groups (P > 0.05). Obese patients exhibited more severe symptoms compared with non-obese patients. L4/L5 stenosis was associated with more severe symptoms compared with stenosis at other levels. Conclusion The oral corticoid regimen used in this study was not effective in the treatment of lumbar canal stenosis. PMID:25099318

  12. [Double responses].

    PubMed

    Motté, G; Dinanian, S; Sebag, C; Drieu, L; Slama, M

    1995-12-01

    Double response is a rare electrocardiographic phenomenon requiring two atrioventricular conduction pathways with very different electrophysiological properties. Double ventricular responses are the usual manifestation: an atrial depolarisation (spontaneous or provoked, anticipated or not) is followed by a first ventricular response dependent on an accessory pathway or a rapid nodal pathway and then a second response resulting from sufficiently delayed transmission through a nodal pathway for the ventricles to have recovered their excitability when the second wave of activation reaches them. A simple curiosity when isolated and occurring under unusual conditions, particularly during electrophysiological investigation of the Wolff-Parkinson-White syndrome, the double response may initiate symptomatic non-reentrant junctional tachycardia when associated with nodal duality and repeating from atria in sinus rhythm. The functional incapacity and resistance to antiarrhythmic therapy may require referral for ablation of the slow pathway.

  13. Effective diffraction gratings via acidic etching of thermally poled glass

    NASA Astrophysics Data System (ADS)

    Kamenskii, A. N.; Reduto, I. V.; Petrikov, V. D.; Lipovskii, A. A.

    2016-12-01

    Relief diffraction gratings are formed via acidic chemical etching of a periodically poled soda-lime glass. The thermal poling under 1000 V DC is performed at 325 °C using a thermally stable glassy-carbon anodic electrode with periodic grooves, the depth of the grooves being of ∼650 nm. Poling-induced modification of the glass results in deepening the glass anodic surface in the regions under the ribs of the anodic electrode due to volume relaxation and in increasing chemical durability of these regions in acidic media comparatively to the virgin glass. Chemical etching of the poled glass in NH4F:8H2O solution allows additional to the thermal poling shaping of the glass surface via faster dissolution of unpoled/less poled glass regions. The morphology of the glass surface before and after the etching is characterized with atomic force and scanning electron microscopy. About 30 min etching provides the formation of ∼0.9 μm in height relief diffraction gratings with the diffraction efficiency close to the theoretically achievable ∼30% for multi-order diffraction. In vivo measuring of the diffraction efficiency in the course of the etching allows precise fabrication of the gratings.

  14. Electrophoretic protein analysis for the identification of doubled haploid 1A-1R, 1B-1R wheat-rye double translocation lines and for the assessment of their genetic stability.

    PubMed

    Vahl, U; Müller, G; Böhme, T

    1993-06-01

    Eighteen available doubled haploid wheat lines with a cytologically proven 1A-1R, 1B-1R double translocation, which where derived via anther culture from four crosses of the 1A-1R wheat-rye translocation cv "Amigo" with several 1B-1R wheat-rye translocation forms, were subjected to electrophoretic seed protein analysis. Besides, the five parents used in the crosses and some other wheat cultivars and doubled haploid lines (19 with a 1B-1R single translocation, 10 with a 1A-1R translocation and 7 without any 1R translocation) were also included in the investigation. It was found that the gliadin patterns visualized after SDS polyacrylamide gel electrophoresis of alcohol-soluble seed protein extracts can differentiate not only 1B-1R and 1A-1R translocation forms from wheats without any 1R-translocation chromosome, but also 1B-1R and 1A-1R wheats from each other. Moreover, 1A-1R, 1B-1R double translocation lines can be distinguished as well due to characteristic differences revealed between 1A-1R and 1B-1R translocation forms. Thus, all of tested dh1- and dh2-grains of the double translocation lines showed the expected doublet: the 1A-1R translocation ("Amigo")-typical rye band and the 1B-1R translocation ("Kawkas")-typical rye band. Consequently, gliadin patterns estimated after SDS electrophoresis may be used as markers for the fast detection of the desired 1A-1R, 1B-1R double translocation forms among 1A-1R single translocation lines, 1B-1R single translocation lines and lines without any 1R-translocation in the progenies of appropriate crosses. Furthermore, by means of gliadin tests on the dh2-generation the excellent stability of the double translocation 1A-1R, 1B-1R during more than one propagation phase has been proven. Estimations of high-molecular weight (HMW) glutenin subunits coded by 1A and 1B chromosomes are compatible with the double translocation constitution. A few deviating results can be explained by crossing-over events. Seed protein analysis

  15. Development of a novel rapid assay to assess the fidelity of DNA double-strand-break repair in human tumour cells

    PubMed Central

    Collis, S. J.; Sangar, V. K.; Tighe, A.; Roberts, S. A.; Clarke, N. W.; Hendry, J. H.; Margison, G. P.

    2002-01-01

    Cellular survival following ionising radiation-mediated damage is primarily a function of the ability to successfully detect and repair DNA double-strand breaks (DSBs). Previous studies have demonstrated that radiosensitivity, determined as a reduction in colony forming ability in vitro, may be related to the incorrect repair (misrepair) of DSBs. The novel rapid dual fluorescence (RDF) assay is a plasmid-based reporter system that rapidly assesses the correct rejoining of a restriction-enzyme produced DSBs within transfected cells. We have utilised this novel assay to determine the fidelity of DSB repair in the prostate tumour cell line LNCaP, the bladder tumour cell line MGH-U1 and a radiosensitive subclone S40b. The two bladder cell lines have been shown in previous studies to differ in their ability to correctly repair plasmids containing a single DSB. Using the RDF assay we found that a substantial portion of LNCaP cells [80.4 ± 5.3(standard error)%] failed to reconstitute reporter gene expression; however, there was little difference in this measure of DSB repair fidelity between the two bladder cell lines (48.3 ± 3.5% for MGH-U1; 39.9 ± 8.2% for S40b). The RDF assay has potential to be developed to study the relationship between DSB repair fidelity and radiosensitivity as well as the mechanisms associated with this type of repair defect. PMID:11788727

  16. Assessment of cetirizine, an antihistamine, to prevent cutaneous reactions to nevirapine therapy: results of the viramune-zyrtec double-blind, placebo-controlled trial.

    PubMed

    Launay, O; Roudière, L; Boukli, N; Dupont, B; Prévoteau du Clary, F; Patey, O; David, F; Lortholary, O; Devidas, A; Piketty, C; Rey, E; Urbinelli, R; Allaert, F A; Tréluyer, J M; Caumes, E

    2004-04-15

    We conducted a 12-week, multicenter, randomized, double-blind, placebo-controlled trial of cetirizine to assess the ability of antihistamines to prevent nevirapine-associated rash in patients infected with human immunodeficiency virus type 1. Patients initiating treatment with nevirapine were randomized to receive either cetirizine, 10 mg q.d. (104 patients), or placebo (96 patients) during the first 6 weeks of therapy. Rash occurred in 22 (11%) of 200 patients; 10 (9.6%) were in the cetirizine group and 12 (12.5%) were in the placebo group (odds ratio [OR], 0.75; 95% confidence interval [CI], 0.31-1.81; P=.5). Five of 22 rashes were cases of hypersensitivity syndrome. The rate of nevirapine discontinuation due to rash was similar in the 2 groups (7.7% and 6.25% in the cetirizine and placebo groups, respectively; P=.4). Multivariate analysis showed no treatment-group effect but indicated that age >40 years (OR, 3.83; 95% CI, 1.4-10.46; P=.008) was associated with an increased risk of rash. Cetirizine has no preventive effect on nevirapine-associated rash.

  17. Assessment of the antidandruff activity of a new shampoo: a randomized, double-blind, controlled study by clinical and instrumental evaluations.

    PubMed

    Sparavigna, Adele; Setaro, Michele; Caserini, Maurizio; Bulgheroni, Anna

    2013-01-01

    The aim of this randomized, double-blind, controlled study was to evaluate the antidandruff activity exerted by a new shampoo on patients affected by dandruff and/or mild seborrheic dermatitis by means of both D-squame technique coupled with image analysis and clinical assessments. Thirty-four patients were enrolled and 1:1 randomly assigned to either a test shampoo or a comparative shampoo group. Treatment schedule was twice a week for 4 weeks. The D-squame technique was shown to be able to objectively record variations in scalp desquamation both between test and comparative groups and within the same group over time. The results obtained with this instrumental approach showed a statistically significant reduction by 52% vs baseline after 2 weeks of treatment. There was an even greater reduction after 4 weeks (-66%). This reduction was statistically significant compared with the comparative group at the same time points. The analysis of all the other parameters (except Wood's lamp) confirmed the superiority of the test vs the comparative shampoo. The test shampoo proved to be safe, well tolerated, and accepted by the patients for cosmetic acceptability and efficacy. The study confirmed the antidandruff efficacy of the test shampoo and its superiority vs the comparative shampoo.

  18. Double Layers in Astrophysics

    NASA Technical Reports Server (NTRS)

    Williams, Alton C. (Editor); Moorehead, Tauna W. (Editor)

    1987-01-01

    Topics addressed include: laboratory double layers; ion-acoustic double layers; pumping potential wells; ion phase-space vortices; weak double layers; electric fields and double layers in plasmas; auroral double layers; double layer formation in a plasma; beamed emission from gamma-ray burst source; double layers and extragalactic jets; and electric potential between plasma sheet clouds.

  19. Double screening

    SciTech Connect

    Gratia, Pierre; Hu, Wayne; Joyce, Austin; Ribeiro, Raquel H.

    2016-06-15

    Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more than one type of screening. Specifically, we focus on a simple model which exhibits both Vainshtein and kinetic screening. We point out that due to the two characteristic length scales in the problem, the type of screening that dominates depends on the mass of the sourcing object, allowing for different phenomenology at different scales. We consider embedding this double screening phenomenology in a broader cosmological scenario and show that the simplest examples that exhibit double screening are radiatively stable.

  20. [Effects of anti-androgens on sexual function. Double-blind comparative studies on allylestrenol and chlormadinone acetate. Part II: Self-assessment questionnaire method].

    PubMed

    Kumamoto, Y; Yamaguchi, Y; Sato, Y; Suzuki, R; Tanda, H; Kato, S; Mori, K; Matsumoto, H; Maki, A; Kadono, M

    1990-02-01

    Allylestrenol (ALE) and chlormadinone acetate (CMA) were administered to patients with prostatomegaly by the double-blind method, and a self-assessment questionnaire method developed by the authors was used to study the influence of these two antiandrogens on their sexual function. Each test drug was orally administered to 58 patients, in a daily dosage of 50 mg for 12 consecutive weeks. The questionnaires consisted of 6 categories each consisting of 5 questions, or 30 questions in total. The 6 categories were "sexual desire," "erectile capacity" and "ejaculation," which relate to the sexual function, and "living environment (including the frequency of sex)," "dysuria" and "dummy (personality)." Each question was graded into 0-10 points, and each patient was requested to circle the number which best described his status. The scores were compiled and statistically analyzed. Many patients were senile. Evaluable answers were obtained for 99 (85.3%) of the 116 patients. Factor analysis based on the preadministration scores confirmed the contents of the questionnaires to be appropriate for the objectives of the present study. Multiple regression analysis revealed a high correlation between the self-assessment scores and objective data (nocturnal penile tumescence values; NPT values) when dropout cases due to a decrease in the sexual function and non-replying cases were excluded. The self-assessment questionnaire method was concluded to be as useful an objective test method as the NPT measurement for examining the sexual function. Aggravation of the "frequency of urination during night" was conspicuous in the CMA group, and there was a significant difference (p less than 0.05) in this parameter between the two groups. Except for this parameter, dysuria was improved in both administration groups, and there was no significant difference in the efficacy of the two drugs. Both drugs tended to suppress overall sexual function, but the suppression was less severe in the ALE

  1. Assessment of the effectiveness of low-level laser therapy on the hands of patients with rheumatoid arthritis: a randomized double-blind controlled trial.

    PubMed

    Meireles, Sandra Mara; Jones, Anamaria; Jennings, Fabio; Suda, Alina Lica; Parizotto, Nivaldo Antônio; Natour, Jamil

    2010-05-01

    Assess the effectiveness of low-level laser therapy on pain reduction and improvement in function in the hands of patients with rheumatoid arthritis. A randomized double-blind controlled trial was carried out on 82 patients with rheumatoid arthritis. The experimental group was submitted to the application of laser therapy, whereas the control group received a placebo laser. Aluminum gallium arsenide laser was used, at a wavelength of 785 nm, dose of 3 J/cm(2) and mean power of 70 mW. The groups were homogenous at the beginning of the study with regard to the main variables (p > 0.05). There were no statistically significant differences between groups in most of the measurements taken at the end of the intervention including the primary variables; the following variables were the exceptions: favoring the experimental group-inflammation of the interphalangeal joint of the right thumb (p = 0.012) and perimetry of the interphalangeal joint of the left thumb (p = 0.013); and favoring the control group-flexion of the proximal interphalangeal joint of the right fifth finger (p = 0.021), perimetry of the third proximal interphalangeal joint of the right hand (p = 0.044), grip strength in the left hand (p = 0.010), and the work domain of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire (p = 0.010). We conclude that low-level aluminum gallium arsenide laser therapy is not effective at the wavelength, dosage, and power studied for the treatment of hands among patients with rheumatoid arthritis.

  2. Transportable data from non-target arthropod field studies for the environmental risk assessment of genetically modified maize expressing an insecticidal double-stranded RNA.

    PubMed

    Ahmad, Aqeel; Negri, Ignacio; Oliveira, Wladecir; Brown, Christopher; Asiimwe, Peter; Sammons, Bernard; Horak, Michael; Jiang, Changjian; Carson, David

    2016-02-01

    As part of an environmental risk assessment, the potential impact of genetically modified (GM) maize MON 87411 on non-target arthropods (NTAs) was evaluated in the field. MON 87411 confers resistance to corn rootworm (CRW; Diabrotica spp.) by expressing an insecticidal double-stranded RNA (dsRNA) transcript and the Cry3Bb1 protein and tolerance to the herbicide glyphosate by producing the CP4 EPSPS protein. Field trials were conducted at 14 sites providing high geographic and environmental diversity within maize production areas from three geographic regions including the U.S., Argentina, and Brazil. MON 87411, the conventional control, and four commercial conventional reference hybrids were evaluated for NTA abundance and damage. Twenty arthropod taxa met minimum abundance criteria for valid statistical analysis. Nine of these taxa occurred in at least two of the three regions and in at least four sites across regions. These nine taxa included: aphid, predatory earwig, lacewing, ladybird beetle, leafhopper, minute pirate bug, parasitic wasp, sap beetle, and spider. In addition to wide regional distribution, these taxa encompass the ecological functions of herbivores, predators and parasitoids in maize agro-ecosystems. Thus, the nine arthropods may serve as representative taxa of maize agro-ecosystems, and thereby support that analysis of relevant data generated in one region can be transportable for the risk assessment of the same or similar GM crop products in another region. Across the 20 taxa analyzed, no statistically significant differences in abundance were detected between MON 87411 and the conventional control for 123 of the 128 individual-site comparisons (96.1%). For the nine widely distributed taxa, no statistically significant differences in abundance were detected between MON 87411 and the conventional control. Furthermore, no statistically significant differences were detected between MON 87411 and the conventional control for 53 out of 56 individual

  3. Assessment of the Efficacy and Safety of BMS-820836 in Patients With Treatment-Resistant Major Depression: Results From 2 Randomized, Double-Blind Studies.

    PubMed

    Bhagwagar, Zubin; Torbeyns, Anne; Hennicken, Delphine; Zheng, Ming; Dunlop, Boadie W; Mathew, Sanjay J; Khan, Arif; Weisler, Richard; Nelson, Craig; Shelton, Richard; Thase, Michael E; Lane, Roger

    2015-08-01

    Two phase 2B, randomized, double-blind studies assessed the efficacy and safety of fixed or flexible dose of triple monoamine uptake inhibitor BMS-820836 in patients with treatment-resistant depression to demonstrate whether switching to BMS-820836 was superior to the continuation of standard antidepressant treatment. Patients with a history of inadequate response to 1 to 3 adequate trials of antidepressant therapies were prospectively treated with duloxetine 60 mg/d for 8 weeks (CN162-006) or duloxetine 60 mg/d or escitalopram 20 mg/d for 7 weeks (CN162-007). Inadequate responders were randomized to continue their prospective phase treatment or switch to flexible-dose (0.5-2 mg/d; CN162-006) or fixed-dose (0.25, 0.5, 1, or 2 mg/d; CN162-007) BMS-820836 for 6 weeks. The primary end point in both studies was mean change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from randomization to study end point. BMS-820836 flexible (0.5-2 mg/d) or fixed dose of 1 mg/d or greater showed efficacy similar to the continuation of antidepressant treatment, with no statistically significant or clinically meaningful differences. In the CN162-006 study, the adjusted mean (SE) change in MADRS total score was -8.7 (0.661) and -8.1 (0.656) for BMS-820836 and duloxetine, respectively (P = 0.526). In the CN162-007 study, the adjusted mean (SE) change in MADRS total score was -7.3 (0.830) and -6.6 (0.842) for BMS-820836 of 1 and 2 mg, respectively, and -6.9 (0.602) for the continuation group (P = 0.910). Thus, BMS-820836 was well tolerated, with no evidence of dose-dependent discontinuations due to adverse events, but it failed to demonstrate superiority to the continuation of an existing antidepressant in patients with treatment-resistant depression.

  4. A randomized double blind crossover placebo-controlled clinical trial to assess the effects of a mouthwash containing chlorine dioxide on oral malodor

    PubMed Central

    Shinada, Kayoko; Ueno, Masayuki; Konishi, Chisato; Takehara, Sachiko; Yokoyama, Sayaka; Kawaguchi, Yoko

    2008-01-01

    Background Previous research has shown the oxidizing properties and microbiological efficacies of chlorine dioxide (ClO2), however, its clinical efficacies on oral malodor have been evaluated only with organoleptic measurements (OM) or sulphide monitors. No clinical studies have investigated the inhibitory effects of ClO2 on volatile sulfur compounds (VSCs) using gas chromatography (GC). The aim of this study was to assess the inhibitory effects of a mouthwash containing ClO2 on morning oral malodor using OM and GC. Methods A randomized, double blind, crossover, placebo-controlled clinical trial was conducted among 15 healthy male volunteers, who were divided into 2 groups. In the first test phase, the group 1 subjects (N = 8) were instructed to rinse with the experimental mouthwash containing ClO2, and those in group 2 (N = 7) to rinse with the placebo mouthwash without ClO2. In the second test, phase after a one week washout period, each group used the opposite mouthwash. Oral malodor was evaluated before rinsing, right after rinsing and every 30 minutes up to 4 hours with OM, and concentrations of hydrogen sulfide (H2S), methyl mercaptan (CH3SH) and dimethyl sulfide ((CH3)2S), the main VSCs of human oral malodor, were evaluated with GC. Results The baseline oral condition in the subjects in the 2 groups did not differ significantly. The mouthwash containing ClO2 improved morning bad breath according to OM and reduced concentrations of H2S, CH3SH and (CH3)2S according to GC up to 4 hours after rinsing. OM scores with ClO2 were significantly lower than those without ClO2 at all examination times. Significant reductions in the concentrations of the three kinds of VSCs measured by GC were also evident at all examination times. The concentrations of the three gases with ClO2 were significantly lower than those without ClO2 at most examination times. Conclusion In this explorative study, ClO2 mouthwash was effective at reducing morning malodor for 4 hours when used by

  5. Assessment of DNA double-strand breaks and γH2AX induced by the topoisomerase II poisons etoposide and mitoxantrone

    PubMed Central

    Smart, Daniel J.; Halicka, H. Dorota; Schmuck, Gabriele; Traganos, Frank; Darzynkiewicz, Zbigniew; Williams, Gary M.

    2008-01-01

    Double-strand breaks (DSBs) are highly deleterious DNA lesions as they lead to chromosome aberrations and/or apoptosis. The formation of nuclear DSBs triggers phosphorylation of histone H2AX on Ser-139 (defined as γH2AX), which participates in the repair of such DNA damage. Our aim was to compare the induction of γH2AX in relation to DSBs induced by topoisomerase II (TOPO II) poisons, etoposide (ETOP) and mitoxantrone (MXT), in V79 cells. DSBs were measured by the neutral comet assay, while γH2AX was quantified using immunocytochemistry and flow cytometry. Stabilized cleavage complexes (SCCs), lesions thought to be responsible for TOPO II poison-induced genotoxicity, were measured using a complex of enzyme–DNA assay. In the case of ETOP, a no observed adverse effect level (NOAEL) and lowest observed effect level (LOEL) for genotoxicity was determined; γH2AX levels paralleled DSBs at all concentrations but significant DNA damage was not detected below 0.5 μg/ml. Furthermore, DNA damage was dependent on the formation of SCCs. In contrast, at low MXT concentrations (0.0001–0.001 μg/ml), induction of γH2AX was not accompanied by increases in DSBs. Rather, DSBs were only significantly increased when SCCs were detected. These findings suggest MXT-induced genotoxicity occurred via at least two mechanisms, possibly related to DNA intercalation and/or redox cycling as well as TOPO II inhibition. Our findings also indicate that γH2AX can be induced by DNA lesions other than DSBs. In conclusion, γH2AX, when measured using immunocytochemical and flow cytometric methods, is a sensitive indicator of DNA damage and may be a useful tool in genetic toxicology screens. ETOP data are consistent with the threshold concept for TOPO II poison-induced genotoxicity and this should be considered in the safety assessment of chemicals displaying an affinity for TOPO II and genotoxic/clastogenic effects. PMID:18423498

  6. Double Description

    ERIC Educational Resources Information Center

    Fluellen, Jerry E., Jr.

    2005-01-01

    In the District of Columbia Public School system, two streams might characterize the professional development component of its strategic plan for high student achievement by 2014. On the one hand, the district has begun a two year professional development program aimed at making every teacher proficient. Knowing, teaching, and assessing standards…

  7. Seeing Double

    NASA Astrophysics Data System (ADS)

    Pesic, Peter

    2003-10-01

    The separateness and connection of individuals is perhaps the central question of human life: What, exactly, is my individuality? To what degree is it unique? To what degree can it be shared, and how? To the many philosophical and literary speculations about these topics over time, modern science has added the curious twist of quantum theory, which requires that the elementary particles of which everything consists have no individuality at all. All aspects of chemistry depend on this lack of individuality, as do many branches of physics. From where, then, does our individuality come? In Seeing Double, Peter Pesic invites readers to explore this intriguing set of questions. He draws on literary and historical examples that open the mind (from Homer to Martin Guerre to Kafka), philosophical analyses that have helped to make our thinking and speech more precise, and scientific work that has enabled us to characterize the phenomena of nature. Though he does not try to be all-inclusive, Pesic presents a broad range of ideas, building toward a specific point of view: that the crux of modern quantum theory is its clash with our ordinary concept of individuality. This represents a departure from the usual understanding of quantum theory. Pesic argues that what is bizarre about quantum theory becomes more intelligible as we reconsider what we mean by individuality and identity in ordinary experience. In turn, quantum identity opens a new perspective on us. Peter Pesic is a Tutor and Musician-in-Residence at St. John's College, Santa Fe, New Mexico. He has a Ph.D. in physics from Stanford University.

  8. Double Your Major, Double Your Return?

    ERIC Educational Resources Information Center

    Del Rossi, Alison F.; Hersch, Joni

    2008-01-01

    We use the 2003 National Survey of College Graduates to provide the first estimates of the effect on earnings of having a double major. Overall, double majoring increases earnings by 2.3% relative to having a single major among college graduates without graduate degrees. Most of the gains from having a double major come from choosing fields across…

  9. The double loop mattress suture

    PubMed Central

    Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

    2014-01-01

    An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p ≤ 0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p ≤ 0.001). Wound gapping is equal, and wound eversion appears significantly improved (p ≤ 0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

  10. Change of coagulation parameters after double plateletpheresis.

    PubMed

    Yilmaz, Mustafa; Dikmen, Tamer; Sonmez, Mehmet; Akdogan, Elif; Durmus, Ahmet; Omay, Serdar Bedii; Ovali, Ercument

    2007-10-01

    In the previous studies, some authors reported that automated apheresis leads to a hypercoagulable state. We tried to find out changes in coagulation parameters after double plateletpheresis in this study. Forty-five donors were recruited to the study, and coagulation parameters were assessed before and after double plateletpheresis. After double plateletpheresis, fibrinogen, factor V, factor VIII and factor IX were decreased compared with the values before apheresis. Although serum levels of this coagulation parameters are decreasing, they are still in the normal limits. Therefore, we suggest that double plateletpheresis is a safe procedure for healthy volunteers taking into account these coagulation parameters.

  11. Double-branched vortex generator

    NASA Technical Reports Server (NTRS)

    Cantwell, E. R.; Westphal, R. V.; Mehta, R. D.

    1985-01-01

    In order to assess the suitability of using a double branched vortex generator in parametric studies involving vortex interactions, an experimental study of the main vortex and secondary flows produced by a double branched vortex generator was conducted in a 20-by-40 cm indraft wind tunnel. Measurements of the cross flow velocities were made with a five hole pressure probe from which vorticity contours and vortex parameters were derived. The results showed that the optimum configuration consisted of chord extensions with the absence of a centerbody.

  12. Assessment of penetration potential of pH responsive double walled biodegradable nanogels coated with eucalyptus oil for the controlled delivery of 5-fluorouracil: In vitro and ex vivo studies.

    PubMed

    Sahu, Prashant; Kashaw, Sushil K; Jain, Sanyog; Sau, Samaresh; Iyer, Arun K

    2017-03-18

    Penetration enhancers coated biodegradable polymeric nanogels loaded with cytotoxic drugs applied via the topical route, can be a promising strategy for improving the chemotherapeutic efficiency of skin cancers. The major objective of proposed research was to investigate the in vitro and ex vivo chemotherapeutic potential of double walled PLGA-chitosan biodegradable nanogel entrapped with 5-fluororuacil (5-FU) coated with eucalyptus oil, topically applied onto the skin. 5-FU was first entrapped in PLGA core by solvent evaporation technique followed by coating with cationic chitosan for ionic interaction with anionic skin cancer cell membrane. A surface coating of eucalyptus oil (1%) was employed to improve the penetration efficacy of the nanogel into stratum corneum. The surface modified biodegradable double walled nanogel was characterized for particle size, charge and thermal properties followed by pH dependent in vitro analysis. Human keratinocyte (HaCaT) cell line was employed for the bio- and cyto-compatibility testing prior to the hemolysis assay and coagulation assessment. A porcine skin ex vivo screening was performed for assessing the penetration potential of the nanogels. DLS and TEM revealed a particle size about 170nm for the double walled nanogels. The nanogels also exhibited high thermal stability as analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). The drug entrapment efficacy was about ~40%. The drug release showed sustained release pattern noted up to 24h. The low hemolysis of 2.39% with short prothrombin time (PT) and activated partial thromboplastin time (APTT) of 14.2 and 35.5s respectively, revealed high biocompatibility of the nanogels. The cellular uptake and localization was assessed by confocal microscopy. The cytotoxicity (MTT assay) on HaCaT cell line demonstrated high cytocompatibilty of the nanogels. An ex vivo evaluation using porcine skin displayed efficient and steady state flux of 5-FU from the biodegradable

  13. Residual electric fields of InGaAs/AlAs/AlAsSb (001) coupled double quantum wells structures assessed by photoreflectance anisotropy

    NASA Astrophysics Data System (ADS)

    González-Fernández, J. V.; Herrera-Jasso, R.; Ulloa-Castillo, N. A.; Ortega-Gallegos, J.; Castro-García, R.; Lastras-Martínez, L. F.; Lastras-Martínez, A.; Balderas-Navarro, R. E.; Mozume, T.; Gozu, S.

    2016-12-01

    We report on photoreflectance anisotropy (PRA) spectroscopy of InGaAs/AlAs/AlAsSb coupled double quantum wells (CDQWs) with extremely thin coupling AlAs barriers grown by molecular beam epitaxy (MBE), with no intentional doping. By probing the in-plane interfacial optical anisotropies (OAs), it is shown that PRA spectroscopy has the ability to detect and distinguish semiconductor layers with quantum dimensions, as the anisotropic photoreflectance (PR) signal stems entirely from buried quantum wells (QWs). In order to account for the experimental PRA spectra, a theoretical model at k = 0, based on a linear electro-optic effect through a piezoelectric shear strain, has been employed to quantify the internal electric fields across the QWs. The dimensionalities of the PR lineshapes were tested by using reciprocal (Fourier) space analysis. Such a complementary test is used in order to correctly employ the PRA model developed here.

  14. A double-blind, placebo-controlled study to assess the mitochondria-targeted antioxidant MitoQ as a disease-modifying therapy in Parkinson's disease.

    PubMed

    Snow, Barry J; Rolfe, Fiona L; Lockhart, Michelle M; Frampton, Christopher M; O'Sullivan, John D; Fung, Victor; Smith, Robin A J; Murphy, Michael P; Taylor, Kenneth M

    2010-08-15

    Multiple lines of evidence point to mitochondrial oxidative stress as a potential pathogenic cause for Parkinson's disease (PD). MitoQ is a powerful mitochondrial antioxidant. It is absorbed orally and concentrates within mitochondria where it has been shown to protect against oxidative damage. We enrolled 128 newly diagnosed untreated patients with PD in a double-blind study of two doses of MitoQ compared with placebo to explore the hypothesis that, over 12 months, MitoQ would slow the progression of PD as measured by clinical scores, particularly the Unified Parkinson Disease Rating Scale. We showed no difference between MitoQ and placebo on any measure of PD progression. MitoQ does not slow the progression of PD, and this finding should be taken into account when considering the oxidative stress hypothesis for the pathogenesis of PD.

  15. Assessment of Denosumab in Korean Postmenopausal Women with Osteoporosis: Randomized, Double-Blind, Placebo-Controlled Trial with Open-Label Extension

    PubMed Central

    Koh, Jung-Min; Chung, Dong Jin; Chung, Yoon-Sok; Kang, Moo-Il; Kim, In-Ju; Min, Yong-Ki; Oh, Han-Jin; Park, Il Hyung; Lee, Yil-Seob; Waterhouse, Brian; Nino, Antonio; Fitzpatrick, Lorraine A.

    2016-01-01

    Purpose The efficacy and safety of denosumab was compared with placebo in Korean postmenopausal women with osteoporosis in this phase III study. Materials and Methods Women aged 60 to 90 years with a T-score of <-2.5 and ≥-4.0 at the lumbar spine or total hip were randomized to a single 60 mg subcutaneous dose of denosumab or placebo for the 6-month double-blind phase. Eligible subjects entered the 6-month open-label extension phase and received a single dose of denosumab 60 mg. Results Baseline demographics were similar in the 62 denosumab- and 64 placebo-treated subjects who completed the double-blind phase. Treatment favored denosumab over placebo for the primary endpoint {mean percent change from baseline in lumbar spine bone mineral density (BMD) at Month 6 [3.2% (95% confidence interval 2.1%, 4.4%; p<0.0001)]}; and secondary endpoints (mean percent change from baseline in lumbar spine BMD at Month 1, total hip, femoral neck, and trochanter BMD at Months 1 and 6, and median percent change from baseline in bone turnover markers at Months 1, 3, and 6). Endpoint improvements were sustained over 12 months in the open-label extension (n=119). There were no new or unexpected safety signals. Conclusion Denosumab was well tolerated and effective in increasing BMD and decreasing bone turnover markers over a 12-month period in Korean postmenopausal women. The findings of this study demonstrate that denosumab has beneficial effects on the measures of osteoporosis in Korean postmenopausal women. PMID:27189284

  16. 15 CFR 990.22 - Prohibition on double recovery.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Prohibition on double recovery. 990.22... NATURAL RESOURCE DAMAGE ASSESSMENTS Authorities § 990.22 Prohibition on double recovery. When taking actions under this part, trustees are subject to the prohibition on double recovery, as provided in 33...

  17. 15 CFR 990.22 - Prohibition on double recovery.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Prohibition on double recovery. 990.22... NATURAL RESOURCE DAMAGE ASSESSMENTS Authorities § 990.22 Prohibition on double recovery. When taking actions under this part, trustees are subject to the prohibition on double recovery, as provided in 33...

  18. [A double gallbladder].

    PubMed

    Mink van der Molen, A B; Salu, M K

    1991-04-06

    A 59-year-old woman is described with symptomatic cholelithiasis. A double gallbladder was incidentally found during abdominal surgery. The literature on a double gallbladder is reviewed with respect to incidence, anatomy, diagnosis and therapy.

  19. Chromosome doubling method

    DOEpatents

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  20. The double identity of linguistic doubling.

    PubMed

    Berent, Iris; Bat-El, Outi; Brentari, Diane; Dupuis, Amanda; Vaknin-Nusbaum, Vered

    2016-11-29

    Does knowledge of language consist of abstract principles, or is it fully embodied in the sensorimotor system? To address this question, we investigate the double identity of doubling (e.g., slaflaf, or generally, XX; where X stands for a phonological constituent). Across languages, doubling is known to elicit conflicting preferences at different levels of linguistic analysis (phonology vs. morphology). Here, we show that these preferences are active in the brains of individual speakers, and they are demonstrably distinct from sensorimotor pressures. We first demonstrate that doubling in novel English words elicits divergent percepts: Viewed as meaningless (phonological) forms, doubling is disliked (e.g., slaflaf < slafmak), but once doubling in form is systematically linked to meaning (e.g., slaf = ball, slaflaf = balls), the doubling aversion shifts into a reliable (morphological) preference. We next show that sign-naive speakers spontaneously project these principles to novel signs in American Sign Language, and their capacity to do so depends on the structure of their spoken language (English vs. Hebrew). These results demonstrate that linguistic preferences doubly dissociate from sensorimotor demands: A single stimulus can elicit diverse percepts, yet these percepts are invariant across stimulus modality--for speech and signs. These conclusions are in line with the possibility that some linguistic principles are abstract, and they apply broadly across language modality.

  1. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    SciTech Connect

    Carr, J. K.; Roy, S.; Skinner, J. L.; Zabuga, A. V.; Rizzo, T. R.

    2014-06-14

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala){sub 5}-Lys-H{sup +} in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly {sup 13}C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and {sup 13}C{sup 18}O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm{sup −1} for both frequencies and couplings, having larger errors only for the frequencies of terminal amides.

  2. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations.

    PubMed

    Carr, J K; Zabuga, A V; Roy, S; Rizzo, T R; Skinner, J L

    2014-06-14

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed "maps," which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala)5-Lys-H(+) in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly (13)C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and (13)C(18)O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm(-1) for both frequencies and couplings, having larger errors only for the frequencies of terminal amides.

  3. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Carr, J. K.; Zabuga, A. V.; Roy, S.; Rizzo, T. R.; Skinner, J. L.

    2014-06-01

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed "maps," which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala)5-Lys-H+ in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13C18O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm-1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides.

  4. Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy of Nonopioid Analgesics on Pain following Arthroscopic Knee Surgery.

    PubMed

    Abdulla, Susanne; Eckhardt, Regina; Netter, Ute; Abdulla, Walied

    2012-01-01

    Purpose. In a randomized, double-blind trial, the efficacy of nonopioid analgesics on postoperative piritramide consumption was compared for pain relief during the first 24 h in patients recovering from arthroscopic knee surgery. Methods. 120 patients were treated with normal saline and/or one of the nonopioid analgesics (parecoxib, metamizole, paracetamol) in addition to piritramide using the PCA pump. Beginning in the postanesthesia care unit (PACU), patients were asked to quantify their pain experience at rest while piritramide consumption was recorded. Results. Piritramide consumption upon arrival in the PACU was high in all groups. However, cumulative consumption in the parecoxib group was significantly lower than that in the placebo group at 6 and 12 h after surgery. At discharge from the PACU, VAS scores dropped in all groups and were significantly lower in the parecoxib group. In the PACU, satisfaction of the patients was moderate and improved with time after surgery. Conclusions. There was statistically significant opioid-saving effect by administering parecoxib with better VAS scores and satisfaction level compared to placebo. The high pain score in the PACU in all groups immediately after recovering from remifentanil-based anesthesia would be prevented if local anesthetics were administered intra-articularly as part of a multimodal analgesic approach.

  5. A randomized, double-blind, placebo-controlled trial to assess the bacterial anti-adhesion effects of cranberry extract beverages.

    PubMed

    Kaspar, Kerrie L; Howell, Amy B; Khoo, Christina

    2015-04-01

    In this study, we examined the ex vivo urinary anti-adhesion activity of low-calorie cranberry extract beverages in both a pilot study (n = 10) and a randomized, double-blind, placebo controlled clinical trial (n = 59). In the pilot study, subjects consumed a cranberry extract beverage (CEB) or a cranberry extract and juice beverage (CEJB), compared to placebo. Both cranberry beverages utilized a standardized cranberry extract powder at a level equivalent to low-calorie cranberry juice cocktail (LCJC) on a PAC content basis. Clean-catch urine samples collected at baseline and post intervention were tested for anti-adhesion activity utilizing a mannose-resistant human red blood cell hemagglutination assay specific for P-fimbriated E. coli. Results from the pilot study indicated that ex vivo anti-adhesion activity for both cranberry treatments were higher (p < 0.05) than placebo. In the clinical trial, we compared CEJB to LCJC and a placebo beverage. Post-consumption urine from both cranberry treatment groups showed significantly higher (p < 0.05) anti-adhesion activity compared to placebo. There were no differences observed in anti-adhesion activity between CJEB and LCJC, indicating similar bioactivity. Therefore, acute beverage consumption of cranberry extract and/or juice provides ex vivo anti-adhesion activity, which may help to improve urinary tract health.

  6. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    PubMed Central

    Carr, J. K.; Zabuga, A. V.; Roy, S.; Rizzo, T. R.; Skinner, J. L.

    2014-01-01

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala)5-Lys-H+ in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13C18O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm−1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides. PMID:24929378

  7. Assessment.

    ERIC Educational Resources Information Center

    Reising, Bob

    1998-01-01

    Argues (guided by "The Challenge of Change: Assessment in the 21st Century") that in the decades ahead, assessment will play an unprecedented role as the vehicle that will influence and guide scheduling, curriculum, and instruction. (SR)

  8. Induction and Rejoining of DNA Double Strand Breaks Assessed by H2AX Phosphorylation in Melanoma Cells Irradiated with Proton and Lithium Beams

    SciTech Connect

    Ibanez, Irene L.; Bracalente, Candelaria; Molinari, Beatriz L.; Palmieri, Monica A.; Policastro, Lucia; Kreiner, Andres J.; Burlon, Alejandro A.; Valda, Alejandro; Navalesi, Daniela; Davidson, Jorge; Davidson, Miguel; Vazquez, Monica; Ozafran, Mabel; Duran, Hebe

    2009-07-15

    Purpose: The aim of this study was to evaluate the induction and rejoining of DNA double strand breaks (DSBs) in melanoma cells exposed to low and high linear energy transfer (LET) radiation. Methods and Materials: DSBs and survival were determined as a function of dose in melanoma cells (B16-F0) irradiated with monoenergetic proton and lithium beams and with a gamma source. Survival curves were obtained by clonogenic assay and fitted to the linear-quadratic model. DSBs were evaluated by the detection of phosphorylated histone H2AX ({gamma}H2AX) foci at 30 min and 6 h post-irradiation. Results: Survival curves showed the increasing effectiveness of radiation as a function of LET. {gamma}H2AX labeling showed an increase in the number of foci vs. dose for all the radiations evaluated. A decrease in the number of foci was found at 6 h post-irradiation for low LET radiation, revealing the repair capacity of DSBs. An increase in the size of {gamma}H2AX foci in cells irradiated with lithium beams was found, as compared with gamma and proton irradiations, which could be attributed to the clusters of DSBs induced by high LET radiation. Foci size increased at 6 h post-irradiation for lithium and proton irradiations in relation with persistent DSBs, showing a correlation with surviving fraction. Conclusions: Our results showed the response of B16-F0 cells to charged particle beams evaluated by the detection of {gamma}H2AX foci. We conclude that {gamma}H2AX foci size is an accurate parameter to correlate the rejoining of DSBs induced by different LET radiations and radiosensitivity.

  9. Comparative analysis of the diagnostic performance of six major Echinococcus granulosus antigens assessed in a double-blind, randomized multicenter study.

    PubMed

    Lorenzo, Carmen; Ferreira, Henrique B; Monteiro, Karina M; Rosenzvit, Mara; Kamenetzky, Laura; García, Hector H; Vasquez, Yessika; Naquira, Cesar; Sánchez, Elizabeth; Lorca, Myriam; Contreras, María; Last, Jerry A; González-Sapienza, Gualberto G

    2005-06-01

    The serodiagnosis of hydatid disease is a valuable instrument for clinical diagnosis and epidemiological surveillance of high-risk populations. In the past decade a wealth of reports on the diagnostic performance of numerous antigens have been produced. However, their diagnostic value has been estimated under different conditions, using different serum collection, therefore precluding their direct comparison. Here we report an unbiased comparison of the same batch of six major E. granulosus antigens, namely, hydatid cyst fluid (HCF), native antigen B (AgB), two recombinant AgB subunits, an AgB-derived synthetic peptide, and recombinant cytosolic malate dehydrogenase from E. granulosus (EgMDH), against the same serum collection. The double-blind analysis was performed using a standardized protocol and receiver operating characteristic (ROC) data analysis by a network of six South American laboratories. High intercenter reproducibility was attained, and the intralaboratory analysis allowed the comparative ranking of the antigen panel. HCF, AgB, and its AgB8/1 subunit exhibited equivalent diagnostic efficiencies, 81.4% +/- 0.5%, 81.3% +/- 0.6%, and 81.9% +/- 2.0%, respectively; with a more favorable balance toward specificity in the case of the last antigen. The diagnostic efficiencies for the other three antigens were 76.8% +/- 6.8%, 69.1% +/- 2.7%, and 66.8% +/- 2.1%, for the peptide, the AgB8/2 subunit, and the EgMDH, respectively. The study also included an analysis of batch-to-batch variation in the diagnostic performance of different HCF regional preparations. Based on these results, a suggested recommendation on the use of these antigens was drawn.

  10. Comparative Analysis of the Diagnostic Performance of Six Major Echinococcus granulosus Antigens Assessed in a Double-Blind, Randomized Multicenter Study

    PubMed Central

    Lorenzo, Carmen; Ferreira, Henrique B.; Monteiro, Karina M.; Rosenzvit, Mara; Kamenetzky, Laura; García, Hector H.; Vasquez, Yessika; Naquira, Cesar; Sánchez, Elizabeth; Lorca, Myriam; Contreras, María; Last, Jerry A.; González-Sapienza, Gualberto G.

    2005-01-01

    The serodiagnosis of hydatid disease is a valuable instrument for clinical diagnosis and epidemiological surveillance of high-risk populations. In the past decade a wealth of reports on the diagnostic performance of numerous antigens have been produced. However, their diagnostic value has been estimated under different conditions, using different serum collection, therefore precluding their direct comparison. Here we report an unbiased comparison of the same batch of six major E. granulosus antigens, namely, hydatid cyst fluid (HCF), native antigen B (AgB), two recombinant AgB subunits, an AgB-derived synthetic peptide, and recombinant cytosolic malate dehydrogenase from E. granulosus (EgMDH), against the same serum collection. The double-blind analysis was performed using a standardized protocol and receiver operating characteristic (ROC) data analysis by a network of six South American laboratories. High intercenter reproducibility was attained, and the intralaboratory analysis allowed the comparative ranking of the antigen panel. HCF, AgB, and its AgB8/1 subunit exhibited equivalent diagnostic efficiencies, 81.4% ± 0.5%, 81.3% ± 0.6%, and 81.9% ± 2.0%, respectively; with a more favorable balance toward specificity in the case of the last antigen. The diagnostic efficiencies for the other three antigens were 76.8% ± 6.8%, 69.1% ± 2.7%, and 66.8% ± 2.1%, for the peptide, the AgB8/2 subunit, and the EgMDH, respectively. The study also included an analysis of batch-to-batch variation in the diagnostic performance of different HCF regional preparations. Based on these results, a suggested recommendation on the use of these antigens was drawn. PMID:15956395

  11. Development of the Resin Infusion between Double Flexible Tooling process : assessment of the viability of in-mold coating and implementation of UV curing.

    SciTech Connect

    Okoli, Okenwa I.

    2004-12-01

    As composites gain wider acceptance in all sectors of the economy, new methodologies must be developed to increase their cost effectiveness in manufacturing. The neoteric Resin Infusion between Double Flexible Tooling (RIDFT) process is undergoing modifications to improve its cost-effectiveness by developing methodologies for in-mold coating and the incorporation of UV curing. In-mold coating is desired by the composites industry since it eliminates the current paint process, which is not only laborious and time consuming, but expensive, and presents safety issues. Two methodologies (paint films and coinfusion) for implementing in-mold coating were investigated. It was demonstrated that thermoformable paint films could be used to produce coated RIDFTed components. Coinfusion was also successfully implemented. This work also investigated the feasibility of designing and incorporating a Cure on Demand system into the RIDFT process, using ultraviolet (UV) light for the curing of composite laminates. The objective was to develop a process for the RIDFT that would eliminate or reduce the inflexibility in the current production process, resulting in shortened production cycle times. UV-cured laminates were produced at a fraction of the time required to produce catalyst-cured laminates. Mechanical and material characterization tests were performed on each of the UV-cured laminates produced. The results were referenced against those obtained for laminates produced using a catalyst curing system to determine their overall quality. The UV-cured laminates, after undergoing tensile and rheological thermal tests, were found to have mechanical and material properties comparable, or in a few instances slightly better, than that of thermally cured laminates.

  12. Evaluation of double formalin--Lugol's fixation in assessing number and biomass of ciliates: an example of estimations at mesoscale in NE Atlantic.

    PubMed

    Karayanni, Hera; Christaki, Urania; Van Wambeke, France; Dalby, Andrew P

    2004-03-01

    Ciliated protozoa are potential grazers of primary and bacterial production and act as intermediaries between picoplankton and copepods and other large suspension feeders. Accurate determination of ciliate abundance and feeding mode is crucial in oceanic carbon budget estimations. However, the impact of different fixatives on the abundance and cell volume of ciliates has been investigated in only a few studies using either laboratory cultures or natural populations. Lugol's solution and formalin are the most commonly used fixatives for the preservation of ciliates samples. In the present study, the aim was to compare 0.4% Lugol's solution and 2% borated-formalin fixation and evaluate the need of counting duplicate samples each using a different fixative. For this, a large number of samples (n = 110) from the NE Atlantic was analyzed in the frame of POMME program (Multidisciplinary Mesoscale Ocean Program). We established a statistically significant relationship (p < 0.0001) between Lugol's and formalin fixed samples for both abundance (r2 = 0.50) and biomass (r2 = 0.76) of aloricate ciliates which showed that counts were higher in Lugol's solution by a factor of 2 and a non-taxon specific cell-loss in formalin. However, loricate ciliate abundance in our samples which were represented primarily by Tintinnus spp. did not show any difference between the two treatments. Abundance and biomass of mixotrophic ciliates (chloroplast-bearing cells) were for various reasons underestimated in both treatments. Our results show that unique fixation by formalin may severely underestimate ciliates abundance and biomass although their population may not alter. For this reason, Lugol's solution is best for the estimation of their abundance and biomass. However, for counts of mixotrophs and the evaluation of the ecological role of ciliates in carbon flux, double fixation is essential. Compromises regarding the fixatives have lead to severe underestimations of mixotrophs in studies

  13. Lutein supplementation in retinitis pigmentosa: PC-based vision assessment in a randomized double-masked placebo-controlled clinical trial [NCT00029289

    PubMed Central

    Bahrami, Hossein; Melia, Michele; Dagnelie, Gislin

    2006-01-01

    Background There is no generally accepted medical or surgical treatment to stop the progressive course of retinitis pigmentosa. Previous studies have suggested lutein as a potential treatment with positive effects on macular pigment density. The objective of this study was to examine the effect of lutein supplementation on preservation of visual function in patients with retinitis pigmentosa (RP) Methods In a double-masked randomized placebo-controlled phase I/II clinical trial with a cross-over design, 34 adult patients with RP were randomized to two groups. One group, consisted of 16 participants, received lutein supplementation (10 mg/d for 12 wks followed by 30 mg/d) for the first 24 weeks and then placebo for the following 24 weeks, while the other group included 18 participants for whom placebo (24 weeks) was administered prior to lutein. Visual acuity, contrast sensitivity, and central visual field were measured at different illumination levels at baseline and every week using a PC-based test at home. Results For visual acuity (VA) at normal illumination level, treatment with lutein reduced logMAR, i.e. improved VA, but this effect was not statistically significant. The changes in normal (100%), low (4%), and very low (0.1%) illumination log CS were not statistically significant (p-values: 0.34, 0.23, and 0.32, respectively). Lutein had a statistically significant effect on visual field (p-value: 0.038) and this effect increased in the model assuming a 6-week delay in effect of lutein. Comparing the development of vision measures against the natural loss expected to occur over the course of 48 weeks, most measures showed reduced decline, and these reductions were significant for normal illumination VA and CS. Conclusion These results suggest that lutein supplementation improves visual field and also might improve visual acuity slightly, although these results should be interpreted cautiously. As a combined phase I and II clinical trial, this study

  14. A double blind randomized placebo controlled phase I/II study assessing the safety and efficacy of allogeneic bone marrow derived mesenchymal stem cell in critical limb ischemia

    PubMed Central

    2013-01-01

    Background Peripheral vascular disease of the lower extremities comprises a clinical spectrum that extends from no symptoms to presentation with critical limb ischemia (CLI). Bone marrow derived Mesenchymal Stem Cells (BM- MSCs) may ameliorate the consequences of CLI due to their combinatorial potential for inducing angiogenesis and immunomodulatory environment in situ. The primary objective was to determine the safety of BM- MSCs in patients with CLI. Methods Prospective, double blind randomized placebo controlled multi-center study was conducted in patients with established CLI as per Rutherford classification in category II-4, III-5, or III-6 with infra-inguinal arterial occlusive disease and were not suitable for or had failed revascularization treatment. The primary end point was incidence of treatment – related adverse events (AE). Exploratory efficacy end points were improvement in rest pain, increase in Ankle Brachial Pressure Index (ABPI), ankle pressure, healing of ulcers, and amputation rates. Twenty patients (BM-MSC: Placebo = 1:1) were administered with allogeneic BM-MSCs at a dose of 2 million cells/kg or placebo (PlasmaLyte A) at the gastrocnemius muscle of the ischemic limb. Results Improvement was observed in the rest pain scores in both the arms. Significant increase in ABPI and ankle pressure was seen in BM-MSC arm compared to the placebo group. Incidence of AEs in the BM-MSC arm was 13 vs. 45 in the placebo arm where as serious adverse events (SAE) were similar in both the arms (5 in BM-MSC and 4 in the placebo group). SAEs resulted in death, infected gangrene, amputations in these patients. It was observed that the SAEs were related to disease progression and not related to stem cells. Conclusion BM-MSCs are safe when injected IM at a dose of 2 million cells/kg body weight. Few efficacy parameters such as ABPI and ankle pressure showed positive trend warranting further studies. Trial registration NIH website (http

  15. Application of the double-contingency principle within BNFL

    SciTech Connect

    Strafford, P.I.D.

    1995-12-31

    Historically, the double-contingency principle has been used for criticality assessment within British Nuclear Fuels plc (BNFL). This paper outlines what is understood by the double-contingency principle to illustrate how it is applied in criticality safety assessments and to highlight various problem areas that are encountered and, where possible, how they might be solved.

  16. Alternative Assessment.

    ERIC Educational Resources Information Center

    Stefonek, Tom; And Others

    1991-01-01

    This special double issue focuses on the issue of alternative assessment and its place in educational reform. "Alternative Assessment: A National Perspective" (T. Stefonek) emphasizes that the fundamental purposes of new assessment methods are grounded in educational goals, meaningful outcomes, and curricular and instructional programs…

  17. Fractal analysis: a novel method to assess roughness organization of implant surface topography.

    PubMed

    Perrotti, Vittoria; Aprile, Guiseppe; Degidi, Marco; Piattelli, Adriano; Iezzi, Giovanna

    2011-01-01

    Surface roughness is important for implant osseointegration. It has mostly been assessed by amplitude and height descriptors. Fractal analysis is derived from fractal geometry and is used to describe the organization of objects found in nature, quantifying their shape complexity with a value. Fractal dimension (Df?) is an index of the space-filling properties of an object and can be used as a parameter that describes the organization of surface roughness. The greater the Df value, the more chaotic the surface topography. The aim of this study was to assess the Df of implants with three different surface topographies to evaluate whether a novel method to measure roughness of implant surface topography could be developed. Forty-five disk-shaped samples (10 x 2 mm) with three different surface topographies were analyzed by scanning electron microscopy: group A, machined surface; group B, sandblasted and acid-etched surface; and group C, sandblasted, acid-etched, and neutralized surface. Images at 20,000x and 50,000x magnification were processed for quantitative analysis of Df using the box-counting method. Df values were correlated to the image magnification. At 20,000x magnification, Df for groups A, B, and C was 1.81, 1.67, and 1.59, respectively. At 50,000x magnification, Df was lower for all examined groups; more specifically, Df was 1.77, 1.59, and 1.42 for groups A, B, and C, respectively. Statistically significant differences were found between groups A and C at both magnifications. Df is used widely and successfully as a measurement to characterize anatomical structures and physiologic and pathologic processes. Df not only provides an index of roughness size values, but also a measure of roughness spatial organization; therefore, it could be a promising method to differentiate between rough surfaces capable of supporting osseointegration.

  18. Observing Double Stars

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.; Fulton, B. J.; Bianco, Federica B.; Martinez, John; Baxter, John; Brewer, Mark; Carro, Joseph; Collins, Sarah; Estrada, Chris; Johnson, Jolyon; Salam, Akash; Wallen, Vera; Warren, Naomi; Smith, Thomas C.; Armstrong, James D.; McGaughey, Steve; Pye, John; Mohanan, Kakkala; Church, Rebecca

    2012-05-01

    Double stars have been systematically observed since William Herschel initiated his program in 1779. In 1803 he reported that, to his surprise, many of the systems he had been observing for a quarter century were gravitationally bound binary stars. In 1830 the first binary orbital solution was obtained, leading eventually to the determination of stellar masses. Double star observations have been a prolific field, with observations and discoveries - often made by students and amateurs - routinely published in a number of specialized journals such as the Journal of Double Star Observations. All published double star observations from Herschel's to the present have been incorporated in the Washington Double Star Catalog. In addition to reviewing the history of visual double stars, we discuss four observational technologies and illustrate these with our own observational results from both California and Hawaii on telescopes ranging from small SCTs to the 2-meter Faulkes Telescope North on Haleakala. Two of these technologies are visual observations aimed primarily at published "hands-on" student science education, and CCD observations of both bright and very faint doubles. The other two are recent technologies that have launched a double star renaissance. These are lucky imaging and speckle interferometry, both of which can use electron-multiplying CCD cameras to allow short (30 ms or less) exposures that are read out at high speed with very low noise. Analysis of thousands of high speed exposures allows normal seeing limitations to be overcome so very close doubles can be accurately measured.

  19. Evidence of DNA double strand breaks formation in Escherichia coli bacteria exposed to alpha particles of different LET assessed by the SOS response.

    PubMed

    Serment-Guerrero, Jorge; Breña-Valle, Matilde; Aguilar-Moreno, Magdalena; Balcázar, Miguel

    2012-12-01

    Ionizing radiation produces a plethora of lesion upon DNA which sometimes is generated among a relatively small region due to clustered energy deposition events, the so called locally multiply damaged sites that could change to DSB. Such clustered damages are more likely to occur in high LET radiation exposures. The effect of alpha particles of different LET was evaluated on the bacterium Escherichia coli either by survival properties or the SOS response activity. Alpha radiation and LET distribution was controlled by means of Nuclear Track Detectors. The results suggest that alpha particles produce two types of lesion: lethal lesions and SOS inducing-mutagenic, a proportion that varies depending on the LET values. The SOS response as a sensitive parameter to assess RBE is mentioned.

  20. A novel double-isotope technique for the enzymatic assay of plasma histamine: application to estimation of mast cell activation assessed by antigen challenge in asthmatics

    SciTech Connect

    Brown, M.J.; Ind, P.W.; Causon, R.; Lee, T.H.

    1982-01-01

    The concentration of plasma histamine may provide an index of mast cell activation (degranulation) and can be measured by a sensitive radioenzymatic assay based on its specific conversion to (/sup 3/H)-methylhistamine in the presence of histamine-N-methyltransferase and (/sup 3/H)-S-adenosyl-L-methionine. In this assay, the separation of excess (/sup 3/H)-S-adenosyl-L-methionine from (/sup 3/H)-methylhistamine requires several steps, for which a correction factors is necessary to maintain precision. In the present modification, duplicate 50-microliters aliquots of each plasma sample were incubated with histamine-N-methyltransferase and (/sup 3/H)-S-adenosyl-L-methionine. A further aliquot, with an added standard of 200 ng/ml histamine, was incubated with histamine-N-methyl-transferase and (/sup 14/C)-S-adenosyl-L-methionine. This standard was converted to (/sup 14/C)-methylhistamine, and its recovery at the end of the assay corrected both for varying efficiency of methylation among plasma samples and for losses during the subsequent extraction and separation stages. The sensitivity of the assay was 25 pg/ml. The intra-assay and interassay coefficients of variation were 7.2% and 11.6%, respectively. In five asthmatics, antigen challenge caused a 28% fall in FEV1, and this was associated with a twofold to threefold rise in plasma histamine concentration. This assay may thus prove a useful method for assessing the role of mast cell release of mediators in vivo.

  1. A novel double-isotope technique for the enzymatic assay of plasma histamine: application to estimation of mast cell activation assessed by antigen challenge in asthmatics.

    PubMed

    Brown, M J; Ind, P W; Causon, R; Lee, T H

    1982-01-01

    The concentration of plasma histamine may provide an index of mast cell activation (degranulation) and can be measured by a sensitive radioenzymatic assay based on its specific conversion to (3H)-methylhistamine in the presence of histamine-N-methyltransferase and (3H)-S-adenosyl-L-methionine. In this assay, the separation of excess (3H)-S-adenosyl-L-methionine from (3H)-methylhistamine requires several steps, for which a correction factors is necessary to maintain precision. In the present modification, duplicate 50-microliters aliquots of each plasma sample were incubated with histamine-N-methyltransferase and (3H)-S-adenosyl-L-methionine. A further aliquot, with an added standard of 200 ng/ml histamine, was incubated with histamine-N-methyl-transferase and (14C)-S-adenosyl-L-methionine. This standard was converted to (14C)-methylhistamine, and its recovery at the end of the assay corrected both for varying efficiency of methylation among plasma samples and for losses during the subsequent extraction and separation stages. The sensitivity of the assay was 25 pg/ml. The intra-assay and interassay coefficients of variation were 7.2% and 11.6%, respectively. In five asthmatics, antigen challenge caused a 28% fall in FEV1, and this was associated with a twofold to threefold rise in plasma histamine concentration. This assay may thus prove a useful method for assessing the role of mast cell release of mediators in vivo.

  2. Multidimensional period doubling structures.

    PubMed

    Lee, Jeong Yup; Flom, Dvir; Ben-Abraham, Shelomo I

    2016-05-01

    This paper develops the formalism necessary to generalize the period doubling sequence to arbitrary dimension by straightforward extension of the substitution and recursion rules. It is shown that the period doubling structures of arbitrary dimension are pure point diffractive. The symmetries of the structures are pointed out.

  3. A randomized double blind placebo controlled trial assessing the efficacy and safety of praziquantel for the treatment of human schistosomiasis during pregnancy

    PubMed Central

    Olveda, Remigio M; Acosta, Luz P; Tallo, Veronica; Baltazar, Palmera I; Lesiguez, Jenny Lind S; Estanislao, Georgette G; Ayaso, Edna B; Monterde, Donna Bella S; Ida, Antonio; Watson, Nora; McDonald, Emily A; Wu, Hannah W; Kurtis, Jonathan D; Friedman, Jennifer F

    2015-01-01

    Summary Background Despite WHO recommendations to offer pregnant women treatment with praziquantel, many nations continue to withhold treatment, awaiting data from controlled trials addressing safety and efficacy. The objectives of the study were to 1) assess whether treatment of pregnant women with schistosomiasis at 12–16 weeks gestation leads to improved maternal and newborn outcomes and 2) collect maternal and newborn safety data. Methods Women who were otherwise healthy and infected with S. japonicum (N=370) were enrolled and randomized 1:1 to receive either over-encapsulated praziquantel (60 mg/kg in split dose) or placebo. The following efficacy outcomes were ascertained: maternal hemoglobin, iron status, and gestational weight gain, birth weight (primary outcome), newborn hemoglobin and iron status. Safety data were collected including immediate reactogenicity, post dosing toxicology ascertained 24 hours after study agent administration, and maternal and newborn serious adverse events. Findings Most women harbored low intensity infections (90.9%). Treatment with praziquantel did not have a significant impact on birth weight (2.85 kg in both groups, Beta −0.002, [0.88, 0.083]) or the incidence of low birth weight (OR 1.319 [0.729, 2.387]. Lack of treatment success may be due to the lack of difference in measures of maternal inflammation at 32 weeks gestation. Treatment with praziquantel resulted in a higher likelihood of treatment success (OR 5.815, [3.52, 9.61], P < 0.0001). Treatment was well tolerated with reactogenicity rates similar to that observed in non-pregnant subjects. There were no significant differences in key safety outcomes including abortion, fetal death in utero and congenital anomalies. Interpretation Results from this study provide important data from a controlled trial in support of the expansion of treatment policies to include pregnant women as recommended by WHO. Funding The trial was funded by the United States National

  4. Emerging double helical nanostructures.

    PubMed

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-08-21

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on 'bottom-up' and 'top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  5. Assessment.

    ERIC Educational Resources Information Center

    Andrews, Theodore E., Ed.

    "The Role of the State in Performance-Based Teacher Education-Certification" by Robert Roth creates a context for viewing how state agencies are approaching performance education. Peter Airasian then explores the value questions that are at the heart of evaluation issues. Fred McDonald looks at "The State of the Art in Performance Assessment," and…

  6. Effects of luseogliflozin, a sodium-glucose co-transporter 2 inhibitor, on 24-h glucose variability assessed by continuous glucose monitoring in Japanese patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled, crossover study.

    PubMed

    Nishimura, R; Osonoi, T; Kanada, S; Jinnouchi, H; Sugio, K; Omiya, H; Ubukata, M; Sakai, S; Samukawa, Y

    2015-08-01

    The aim of the present study was to determine the effects of luseogliflozin on 24-h glucose levels, assessed by continuous glucose monitoring, and on pharmacodynamic variables measured throughout the day. In this double-blind, placebo-controlled, crossover study, 37 patients with type 2 diabetes mellitus inadequately controlled with diet and exercise were randomized into two groups. Patients in each group first received luseogliflozin then placebo for 7 days each, or vice versa. After 7 days of treatment, the mean 24-h glucose level was significantly lower with luseogliflozin than with placebo [mean (95% confidence interval) 145.9 (134.4-157.5) mg/dl vs 168.5 (156.9-180.0) mg/dl; p < 0.001]. The proportion of time spent with glucose levels ≥70 to ≤180 mg/dl was significantly greater with luseogliflozin than with placebo [median (interquartile range) 83.2 (67.7-96.5)% vs 71.9 (46.9-83.3)%; p < 0.001] without inducing hypoglycaemia. The decrease in glucose levels was accompanied by reductions in serum insulin levels throughout the day.

  7. Advanced double layer capacitors

    NASA Technical Reports Server (NTRS)

    Sarangapani, S.; Lessner, P.; Forchione, J.; Laconti, A. B.

    1989-01-01

    There is a need for large amounts of power to be delivered rapidly in a number of airborne and space systems. Conventional, portable power sources, such as batteries, are not suited to delivering high peak power pulses. The charge stored at the electrode-electrolyte double layer is, however, much more assessible on a short time scale. Devices exploiting this concept were fabricated using carbon and metal oxides (Pinnacle Research) as the electrodes and sulfuric acid as the electrolyte. The approach reported, replaces the liquid sulfuric acid electrolyte with a solid ionomer electrolyte. The challenge is to form a solid electrode-solid ionomer electrolyte composite which has a high capacitance per geometric area. The approach to maximize contact between the electrode particles and the ionomer was to impregnate the electrode particles using a liquid ionomer solution and to bond the solvent-free structure to a solid ionomer membrane. Ruthenium dioxide is the electrode material used. Three strategies are being pursued to provide for a high area electrode-ionomer contact: mixing of the RuOx with a small volume of ionomer solution followed by filtration to remove the solvent, and impregnation of the ionomer into an already formed RuOx electrode. RuOx powder and electrodes were examined by non-electrochemical techniques. X-ray diffraction has shown that the material is almost pure RuO2. The electrode structure depends on the processing technique used to introduce the Nafion. Impregnated electrodes have Nafion concentrated near the surface. Electrodes prepared by the evaporation method show large aggregates of crystals surrounded by Nafion.

  8. The concept of double inlet-double outlet right ventricle: a distinct congenital heart disease.

    PubMed

    Spadotto, Veronica; Frescura, Carla; Ho, Siew Yen; Thiene, Gaetano

    The aim of this study was to estimate the incidence and to analyze the anatomy of double inlet-double outlet right ventricle complex and its associated cardiac anomalies in our autopsy series. Among the 1640 hearts with congenital heart disease of our Anatomical Collection, we reviewed the specimens with double inlet-double outlet right ventricle, according to the sequential-segmental analysis, identifying associated cardiac anomalies and examining lung histology to assess the presence of pulmonary vascular disease. We identified 14 hearts with double inlet-double outlet right ventricle (0.85%). Right atrial isomerism was observed in 10 hearts, situs solitus in 3 and left atrial isomerism in one. Regarding the mode of atrioventricular connection, all hearts but one had a common atrioventricular valve. Systemic or pulmonary venous abnormalities were noted in all patients with atrial isomerism. In nine patients a valvular or subvalvular pulmonary stenosis was present. Among the functionally "univentricular hearts", double inlet- double outlet right ventricle represents a peculiar entity, mostly in association with right atrial isomerism. Multiple cardiac anomalies are associated and may complicate surgical repair.

  9. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  10. A double-blind, randomized trial, including frequent patient–physician contacts and Ramadan-focused advice, assessing vildagliptin and gliclazide in patients with type 2 diabetes fasting during Ramadan: the STEADFAST study

    PubMed Central

    Hassanein, Mohamed; Abdallah, Khalifa; Schweizer, Anja

    2014-01-01

    Background Several observational studies were conducted with vildagliptin in patients with type 2 diabetes mellitus (T2DM) fasting during Ramadan, showing significantly lower incidences of hypoglycemia with vildagliptin versus sulfonylureas, including gliclazide. It was of interest to complement the existing real-life evidence with data from a randomized, double-blind, clinical trial. Clinical Trials Identifier NCT01758380. Methods This multiregional, double-blind study randomized 557 patients with T2DM (mean glycated hemoglobin [HbA1c], 6.9%), previously treated with metformin and any sulfonylurea to receive either vildagliptin (50 mg twice daily) or gliclazide plus metformin. The study included four office visits (three pre-Ramadan) and multiple telephone contacts, as well as Ramadan-focused advice. Hypoglycemic events were assessed during Ramadan; HbA1c and weight were analyzed before and after Ramadan. Results The proportion of patients reporting confirmed (<3.9 mmol/L and/or severe) hypoglycemic events during Ramadan was 3.0% with vildagliptin and 7.0% with gliclazide (P=0.039; one-sided test), and this was 6.0% and 8.7%, respectively, for any hypoglycemic events (P=0.173). The adjusted mean change pre- to post-Ramadan in HbA1c was 0.05%±0.04% with vildagliptin and −0.03%±0.04% with gliclazide, from baselines of 6.84% and 6.79%, respectively (P=0.165). In both groups, the adjusted mean decrease in weight was −1.1±0.2 kg (P=0.987). Overall safety was similar between the treatments. Conclusion In line with the results from previous observational studies, vildagliptin was shown in this interventional study to be an effective, safe, and well-tolerated treatment in patients with T2DM fasting during Ramadan, with a consistently low incidence of hypoglycemia across studies, accompanied by good glycemic and weight control. In contrast, gliclazide showed a lower incidence of hypoglycemia in the present interventional than the previous observational studies. This

  11. Assessment of the effectiveness and safety of Ethosuximide in the Treatment of non-Diabetic Peripheral Neuropathic Pain: EDONOT—protocol of a randomised, parallel, controlled, double-blinded and multicentre clinical trial

    PubMed Central

    Kerckhove, Nicolas; Mallet, Christophe; Pereira, Bruno; Chenaf, Chouki; Duale, Christian; Dubray, Claude; Eschalier, Alain

    2016-01-01

    Introduction Currently available analgesics are ineffective in 30–50% of patients suffering from neuropathic pain and often induce deleterious side effects. T-type calcium channel blockers (mibefradil, ethosuximide, NNC 55-0396) are of great interest for the development of new symptomatic treatments of neuropathic pain, due to their various effects on pain perception. Interestingly, ethosuximide, which has already been approved for treating epilepsy, is available on the European market for clinical use. Despite numerous preclinical data demonstrating an antinociceptive effect of ethosuximide in various animal models of neuropathic pain, no clinical studies have been published to date on the analgesic efficacy of ethosuximide in patients with neuropathic pain. Methods and analysis The Ethosuximide in the Treatment of non-Diabetic Peripheral Neuropathic Pain (EDONOT) trial is a randomised, parallel, controlled, double-blinded, multicentre clinical study. It is the first clinical trial to evaluate the efficacy and safety of ethosuximide in the treatment of non-diabetic peripheral neuropathic pain. Adult patients exhibiting peripheral neuropathic pain (Numeric Rating Scale (NRS) ≥4 and Douleur Neuropathique 4 (DN4)≥4) for at least 3 months and under stable analgesic treatment for at least 1 month will be included. Patients (n=220) will be randomly assigned to receive either ethosuximide or control treatment for 6 weeks following a 1 week run-in period. The primary end point is the intensity of neuropathic pain, assessed by NRS (0–10) before and after 6 weeks of treatment. The secondary end points are safety (adverse events are collected during the study: daily by the patient on the logbook and during planned phone calls by investigators), the intensity and features of neuropathic pain (assessed by Brief Pain Inventory (BPI) and Neuropathic Pain Symptom Inventory (NPSI) questionnaires) and health-related quality of life (assessed by Medical Outcome

  12. A randomized, double-blind, placebo-controlled, multiple-dose, parallel-group clinical trial to assess the effects of teduglutide on gastric emptying of liquids in healthy subjects

    PubMed Central

    2014-01-01

    Background Teduglutide, a recombinant analog of human glucagon-like peptide (GLP)-2, is a novel therapy recently approved for the treatment of adult patients with short bowel syndrome who are dependent on parenteral support. Previous studies assessing the effect of GLP-2 on gastric emptying in humans have yielded inconsistent results, with some studies showing no effect and others documenting a GLP-2–dependent delay in gastric emptying. The primary objective of this study was to assess the effect of teduglutide on gastric emptying of liquids in healthy subjects, as measured by the pharmacokinetics of acetaminophen. Methods This double-blind, parallel-group, single-center study enrolled and randomized 36 healthy subjects (22 men, 14 women) to receive subcutaneous doses of teduglutide 4 mg or placebo (2:1 ratio; 23:13) once daily on Days 1 through 10 in the morning. Gastric emptying of a mixed nutrient liquid meal was assessed by measuring acetaminophen levels predose and at 0.25, 0.5, 0.75, 1, 1.25, 1.5, 2, 3, 3.5, 4, 5, 6, 8, 10, 12, and 14 hours after administration of 1000 mg acetaminophen on Days 0 and 10. The primary study endpoint was a pharmacokinetic analysis of acetaminophen absorption in subjects receiving teduglutide or placebo. Results No significant differences in gastric emptying of liquids (acetaminophen area under the concentration [AUC] vs time curve from time 0 to the last measurable concentration, AUC extrapolated to infinity, maximum concentration [Cmax], and time to Cmax) were observed on Day 10 in subjects receiving teduglutide 4 mg versus subjects receiving placebo. There were no serious adverse events (AEs), deaths, or discontinuations due to an AE reported during the study. Conclusions Teduglutide 4 mg/day for 10 days does not affect gastric emptying of liquids in healthy subjects as measured by acetaminophen pharmacokinetics. No unexpected safety signals were observed. Trial registration This study was registered at Clinical

  13. Examples of Optical Assessment of Surface Cleanliness of Genesis Samples

    NASA Technical Reports Server (NTRS)

    Rodriquez, Melissa C.; Allton, J. H.; Burkett, P. J.; Gonzalez, C. P.

    2013-01-01

    Optical microscope assessment of Genesis solar wind collector surfaces is a coordinated part of the effort to obtain an assessed clean subset of flown wafer material for the scientific community. Microscopic survey is typically done at 50X magnification at selected approximately 1 square millimeter areas on the fragment surface. This survey is performed each time a principle investigator (PI) returns a sample to JSC for documentation as part of the established cleaning plan. The cleaning plan encompasses sample handling and analysis by Genesis science team members, and optical survey is done at each step in the process. Sample surface cleaning is performed at JSC (ultrapure water [1] and UV ozone cleaning [2]) and experimentally by other science team members (acid etch [3], acetate replica peels [4], CO2 snow [5], etc.). The documentation of each cleaning method can potentially be assessed with optical observation utilizing Image Pro Plus software [6]. Differences in particle counts can be studied and discussed within analysis groups. Approximately 25 samples have been identified as part of the cleaning matrix effort to date.

  14. Bilateral double level tibial lengthening in dwarfism☆

    PubMed Central

    Burghardt, Rolf D.; Yoshino, Koichi; Kashiwagi, Naoya; Yoshino, Shigeo; Bhave, Anil; Paley, Dror; Herzenberg, John E.

    2015-01-01

    Purpose Outcome assessment after double level tibial lengthening in patients with dwarfism. Methods Fourteen patients with dwarfism were analyzed after bilateral simultaneous double level tibial lengthening. Results Average age was 15.1 years. Average lengthening was 13.5 cm. The two levels were lengthened by an average of 7.5 cm proximally and 6.0 cm distally. Concomitant deformities were also addressed during lengthening. External fixation treatment time averaged 8.8 months. Healing index averaged 0.7 months/cm. Conclusion Bilateral tibial lengthening for dwarfism is difficult, but the results are usually quite gratifying. PMID:26566326

  15. A randomized, double blind, cross-over, placebo-controlled clinical trial to assess the effects of Candesartan on the insulin sensitivity on non diabetic, non hypertense subjects with dysglyce mia and abdominal obesity. "ARAMIA"

    PubMed Central

    López-Jaramillo, Patricio; Pradilla, Lina P; Lahera, Vicente; Sieger, Federico A Silva; Rueda-Clausen, Christian F; Márquez, Gustavo A

    2006-01-01

    Background The raising prevalence of type-2 diabetes mellitus and obesity has been recognized as a major problem for public health, affecting both developed and developing countries. Impaired fasting plasma glucose has been previously associated with endothelial dysfunction, higher levels of inflammatory markers and increased risk of developing insulin resistance and cardiovascular events. Besides life-style changes, the blockade of the renin-angiotensin system has been proposed as a useful alternative intervention to improve insulin resistance and decrease the number of new type-2 diabetes cases. The aim of this clinical trial is to study the effect of the treatment with Candesartan, an angiotensin II receptor antagonist, on the insulin resistance, the plasma levels of adipoquines, oxidative stress and prothrombotic markers, in a group of non diabetic, non hypertensive, dysglycemic and obese subjects. Methods and design A randomized, double blind, cross-over, placebo-controlled, clinical trial was designed to assess the effects of Candesartan (up to 32 mg/day during 6 months) on the Homeostasis Model Assessment (HOMA) index, lipid profile, protrombotic state, oxidative stress and plasma levels of inflammatory markers. The participants will be recruited in the "Fundación Cardiovascular de Colombia". Subjects who fullfil selection criteria will receive permanent educational, nutritional and exercise support during their participation in the study. After a 15 days-run-in period with placebo and life-style recommendations, the patients who have a treatment compliance equal or greater than 80% will be randomlly assigned to one of the treatment groups. Group A will receive Candesartan during 6 months and placebo during 6 months. Group B will receive placebo during the first 6 months, and then, Candesartan during the last 6 months. Control visits will be programed monthly and all parameters of interest will be evaluated every 6 months. Hypothesis Treatment with

  16. Double checking: a second look

    PubMed Central

    Chreim, Samia; Forster, Alan

    2015-01-01

    Abstract Rationale, aims and objectives Double checking is a standard practice in many areas of health care, notwithstanding the lack of evidence supporting its efficacy. We ask in this study: ‘How do front line practitioners conceptualize double checking? What are the weaknesses of double checking? What alternate views of double checking could render it a more robust process?’ Method This is part of a larger qualitative study based on 85 semi‐structured interviews of health care practitioners in general internal medicine and obstetrics and neonatology; thematic analysis of the transcribed interviews was undertaken. Inductive and deductive themes are reported. Results Weaknesses in the double checking process include inconsistent conceptualization of double checking, double (or more) checking as a costly and time‐consuming procedure, double checking trusted as an accepted and stand‐alone process, and double checking as preventing reporting of near misses. Alternate views of double checking that would render it a more robust process include recognizing that double checking requires training and a dedicated environment, Introducing automated double checking, and expanding double checking beyond error detection. These results are linked with the concepts of collective efficiency thoroughness trade off (ETTO), an in‐family approach, and resilience. Conclusion(s) Double checking deserves more questioning, as there are limitations to the process. Practitioners could view double checking through alternate lenses, and thus help strengthen this ubiquitous practice that is rarely challenged. PMID:26568537

  17. Double-helix stellarator

    SciTech Connect

    Moroz, P.E.

    1997-09-01

    A new stellarator configuration, the Double-Helix Stellarator (DHS), is introduced. This novel configuration features a double-helix center post as the only helical element of the stellarator coil system. The DHS configuration has many unique characteristics. One of them is the extreme low plasma aspect ratio, A {approx} 1--1.2. Other advantages include a high enclosed volume, appreciable rotational transform, and a possibility of extreme-high-{beta} MHD equilibria. Moreover, the DHS features improved transport characteristics caused by the absence of the magnetic field ripple on the outboard of the torus. Compactness, simplicity and modularity of the coil system add to the DHS advantages for fusion applications.

  18. Double arch mirror study

    NASA Technical Reports Server (NTRS)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  19. Double Photoionization Near Threshold

    NASA Technical Reports Server (NTRS)

    Wehlitz, Ralf

    2007-01-01

    The threshold region of the double-photoionization cross section is of particular interest because both ejected electrons move slowly in the Coulomb field of the residual ion. Near threshold both electrons have time to interact with each other and with the residual ion. Also, different theoretical models compete to describe the double-photoionization cross section in the threshold region. We have investigated that cross section for lithium and beryllium and have analyzed our data with respect to the latest results in the Coulomb-dipole theory. We find that our data support the idea of a Coulomb-dipole interaction.

  20. Sun Packs Double Punch

    NASA Video Gallery

    On August 3, the sun packed a double punch, emitting a M6.0-class flare at 9:43 am EDT. This video is of the second, slightly stronger M9.3-class flare at 11:41 pm EDT. Both flares had significant ...

  1. Rosette (Double Blossom)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rosette, or double blossom, is a serious disease of erect blackberries that is limited to the genus Rubus. Rosette may occur on trailing blackberries and dewberries, but rarely on red and black raspberries. In the United States, rosette occurs from New Jersey to Illinois and southwest to Texas and i...

  2. Double resonator cantilever accelerometer

    DOEpatents

    Koehler, D.R.

    1982-09-23

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  3. Double resonator cantilever accelerometer

    DOEpatents

    Koehler, Dale R.

    1984-01-01

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  4. Teaching the Double Layer.

    ERIC Educational Resources Information Center

    Bockris, J. O'M.

    1983-01-01

    Suggests various methods for teaching the double layer in electrochemistry courses. Topics addressed include measuring change in absolute potential difference (PD) at interphase, conventional electrode potential scale, analyzing absolute PD, metal-metal and overlap electron PDs, accumulation of material at interphase, thermodynamics of electrified…

  5. Design for Double Rainbow

    ERIC Educational Resources Information Center

    Thomas, Lisa Carlucci

    2011-01-01

    Rare is the inspirational, spontaneous, transformative moment shared among 20 million people. In the summer of 2010, people around the world were moved by the sighting of a double rainbow--almost a triple rainbow--"all the way across the sky" in Yosemite National Park. Caught on video and posted to by YouTube by Paul Vasquez in January 2010, the…

  6. Double Helix Revisited.

    ERIC Educational Resources Information Center

    Glickstein, Neil M.

    1995-01-01

    Describes the use of James Watson's book, "The Double Helix," as a multidisciplinary way of introducing students to actual science; the scientific method; dilemmas encountered in the world of research; and the rich setting of personalities, politics, and history in post-World War II Europe. (MKR)

  7. Double-Glazing Interferometry

    ERIC Educational Resources Information Center

    Toal, Vincent; Mihaylova, Emilia M.

    2009-01-01

    This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for…

  8. Memory, double, shadow, and evil.

    PubMed

    McNamara, P

    1994-04-01

    In order to examine shadow dynamics the author explores the phenomenology and mythological associations of the 'double' or Doppelgänger. Current Jungian-inspired theories concerning relations of shadow and double are found to be limited because they do not explain (1) the process of personification of the psychic complex which gives rise to the double, (2) the immediate conditions under which doubling occurs, (3) the conditions which lead to the assignment of evil qualities to the double as shadow. The paper seeks to remedy each of the above limitations by redescribing shadow/double phenomena in terms of autonomous memory phenomena, both personal and trans-personal.

  9. MTRX1011A, a humanized anti-CD4 monoclonal antibody, in the treatment of patients with rheumatoid arthritis: a Phase I randomized, double-blind, placebo-controlled study incorporating pharmacodynamic biomarker assessments

    PubMed Central

    2011-01-01

    Introduction The purpose of this study was to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of the humanized anti-CD4 monoclonal antibody MTRX1011A in a randomized, double-blind placebo-controlled Phase 1 study in patients with rheumatoid arthritis (RA). Methods In the single ascending dose (SAD) portion of the study, patients received single doses of a placebo or MTRX1011A at 0.3, 1.0, 3.5 and 7.0 mg/kg intravenously (IV) or 1.0 and 3.5 mg/kg subcutaneously (SC), followed by five weeks of evaluation. In the multi-dose (MD) portion of the study, placebo or MTRX1011A was administered weekly for eight doses at 1.5 or 3.5 mg/kg SC, or 5 mg/kg IV, followed by eight weeks of evaluation. Results MTRX1011A was well tolerated in the SAD phase up to 7 mg/kg IV and in the MD phase up to 1.5 mg/kg SC. At weekly doses of 3.5 mg/kg SC and 5 mg/kg IV, a moderate pruritic papular rash was observed in some MTRX1011A-treated patients, which was considered a dose-limiting toxicity for this clinical indication. No serious adverse events occurred in any cohort. Reduction in disease activity was modest. PD assessments demonstrated that MTRX1011A induced a dose-dependent down-modulation of CD4 expression on peripheral blood CD4 T cells, CD4 receptor occupancy, increases in serum sCD4-MTRX1011A complexes and up-regulation of CD69 on T cells, but was non-depleting. Conclusions The maximum tolerated dose of MTRX1011A was 1.5 mg/kg SC administered weekly. At this dose MTRX1011A did not achieve maximum PD activity expected to be required for reduction in disease activity. PMID:22029963

  10. Multicenter, double-blind, randomized, phase II trial to assess the safety and efficacy of ceftolozane-tazobactam plus metronidazole compared with meropenem in adult patients with complicated intra-abdominal infections.

    PubMed

    Lucasti, Christopher; Hershberger, Ellie; Miller, Benjamin; Yankelev, Sara; Steenbergen, Judith; Friedland, Ian; Solomkin, Joseph

    2014-09-01

    Ceftolozane-tazobactam (TOL-TAZ) is a novel antibacterial with activity against Pseudomonas aeruginosa and other common Gram-negative pathogens, including extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, that are associated with complicated intra-abdominal infections (cIAIs). This prospective, double-blind, randomized, multicenter, phase II trial assessed patient clinical and microbiological responses to and the safety of TOL-TAZ plus metronidazole compared with those of meropenem. Hospitalized adults with cIAIs that required surgical intervention were randomized (2:1) to receive intravenous (i.v.) TOL-TAZ (1.5 g [containing 1,000 mg TOL and 500 mg TAZ] every 8 h [q8h]) with or without i.v. metronidazole (500 mg q8h) or i.v. meropenem (1 g q8h) for 4 to 7 days. The primary endpoint was the clinical response at the test-of-cure visit in the microbiologically modified intent-to-treat (mMITT) and microbiologically evaluable (ME) populations. Secondary measures included the patients' microbiological response and safety. In total, 82 patients received TOL-TAZ (90.2% with metronidazole), and 39 received meropenem. For the mMITT population, clinical cure was seen in 83.6% of the patients (51/61; 95% confidence interval [CI], 71.9 to 91.8) who received TOL-TAZ and 96.0% of the patients (24/25; 95% CI, 79.6 to 99.9) who received meropenem (difference, -12.4%; 95% CI, -34.9% to 11.1%); in the ME population, clinical cure was seen in 88.7% and 95.8% of the patients (difference, -7.1%; 95% CI, -30.7% to 16.9%) who received TOL-TAZ and meropenem, respectively. TOL-TAZ demonstrated microbiological success against Escherichia coli (89.5%), Klebsiella pneumoniae (100%), and P. aeruginosa (100%). The adverse event rates were similar in the groups (50.0% with TOL-TAZ and 48.8% with meropenem). TOL-TAZ in combination with metronidazole was well tolerated and resulted in clinical and microbiological success rates supportive of further clinical development in

  11. Double Degrees: Double the Trouble or Twice the Return?

    ERIC Educational Resources Information Center

    Russell, A. Wendy; Dolnicar, Sara; Ayoub, Marina

    2008-01-01

    Double degrees (also called joint or combined degrees)--programs of study combining two bachelor degrees--are increasingly popular in Australian universities, particularly among women. A case study using qualitative and quantitative surveys of current and past double degree students is presented. The study indicates that double degrees benefit…

  12. Tests on Double Layer Metalization

    NASA Technical Reports Server (NTRS)

    Woo, D. S.

    1983-01-01

    28 page report describes experiments in fabrication of integrated circuits with double-layer metalization. Double-layer metalization requires much less silicon "real estate" and allows more flexibility in placement of circuit elements than does single-layer metalization.

  13. Measuring the Double Helix

    SciTech Connect

    Mathew-Fenn, R.S.; Das, R.; Harbury, P.A.B.

    2009-05-26

    DNA is thought to behave as a stiff elastic rod with respect to the ubiquitous mechanical deformations inherent to its biology. To test this model at short DNA lengths, we measured the mean and variance of end-to-end length for a series of DNA double helices in solution, using small-angle x-ray scattering interference between gold nanocrystal labels. In the absence of applied tension, DNA is at least one order of magnitude softer than measured by single-molecule stretching experiments. Further, the data rule out the conventional elastic rod model. The variance in end-to-end length follows a quadratic dependence on the number of base pairs rather than the expected linear dependence, indicating that DNA stretching is cooperative over more than two turns of the DNA double helix. Our observations support the idea of long-range allosteric communication through DNA structure.

  14. Algebra of Majorana doubling.

    PubMed

    Lee, Jaehoon; Wilczek, Frank

    2013-11-27

    Motivated by the problem of identifying Majorana mode operators at junctions, we analyze a basic algebraic structure leading to a doubled spectrum. For general (nonlinear) interactions the emergent mode creation operator is highly nonlinear in the original effective mode operators, and therefore also in the underlying electron creation and destruction operators. This phenomenon could open up new possibilities for controlled dynamical manipulation of the modes. We briefly compare and contrast related issues in the Pfaffian quantum Hall state.

  15. Colloidal Double Quantum Dots

    PubMed Central

    2016-01-01

    Conspectus Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole–dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single

  16. Colloidal Double Quantum Dots.

    PubMed

    Teitelboim, Ayelet; Meir, Noga; Kazes, Miri; Oron, Dan

    2016-05-17

    Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole-dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single photon

  17. Effect of acid etching on bond strength of nanoionomer as an orthodontic bonding adhesive

    PubMed Central

    Khan, Saba; Verma, Sanjeev K.; Maheshwari, Sandhya

    2015-01-01

    Aims: A new Resin Modified Glass Ionomer Cement known as nanoionomer containing nanofillers of fluoroaluminosilicate glass and nanofiller 'clusters' has been introduced. An in-vitro study aimed at evaluating shear bond strength (SBS) and adhesive remnant index (ARI) of nanoionomer under etching/unetched condition for use as an orthodontic bonding agent. Material and Methods: A total of 75 extracted premolars were used, which were divided into three equal groups of 25 each: 1-Conventional adhesive (Enlight Light Cure, SDS, Ormco, CA, USA) was used after and etching with 37% phosphoric acid for 30 s, followed by Ortho Solo application 2-nanoionomer (Ketac™ N100, 3M, ESPE, St. Paul, MN, USA) was used after etching with 37% phosphoric acid for 30 s 3-nanoionomer was used without etching. The SBS testing was performed using a digital universal testing machine (UTM-G-410B, Shanta Engineering). Evaluation of ARI was done using scanning electron microscopy. The SBS were compared using ANOVA with post-hoc Tukey test for intergroup comparisons and ARI scores were compared with Chi-square test. Results: ANOVA (SBS, F = 104.75) and Chi-square (ARI, Chi-square = 30.71) tests revealed significant differences between groups (P < 0.01). The mean (SD) SBS achieved with conventional light cure adhesive was significantly higher (P < 0.05) (10.59 ± 2.03 Mpa, 95% CI, 9.74-11.41) than the nanoionomer groups (unetched 4.13 ± 0.88 Mpa, 95% CI, 3.79-4.47 and etched 9.32 ± 1.87 Mpa, 95% CI, 8.58-10.06). However, nanoionomer with etching, registered SBS in the clinically acceptable range of 5.9–7.8 MPa, as suggested by Reynolds (1975). The nanoionomer groups gave significantly lower ARI values than the conventional adhesive group. Conclusion: Based on this in-vitro study, nanoionomer with etching can be successfully used as an orthodontic bonding agent leaving less adhesive remnant on enamel surface, making cleaning easier. However, in-vivo studies are needed to confirm the validity of present findings. PMID:26955629

  18. Interaction morphology and bond strength of nanofilled simplified-step adhesives to acid etched dentin

    PubMed Central

    Di Hipólito, Vinicius; Reis, André Figueiredo; Mitra, Sumita B.; de Goes, Mario Fernando

    2012-01-01

    Objective: To evaluate the effect of nanofillers incorporated into adhesives on the microtensile bond strength (μ-TBS) and interfacial micromorphology to dentin. Methods: The occlusal enamel of 5 human molars was removed and each tooth sectioned into four quarters. The exposed dentin was treated with one of the following adhesives: Adper Single Bond (SB-unfilled), OptiBond Solo Plus (OS-barium aluminoborosilicate, 400nm Ø), Prime & Bond NT (NT-colloidal silica, 7–40 nm Ø) and Adper Single Bond 2 (SB2-colloidal silica, 5nm Ø). Cylinders of resin-based composite were constructed on the adhesive layers. After 24-hour storage, the restored tooth-quadrants were sectioned to obtain stick-shaped specimens (0.8 mm2, cross-sectional area) and submitted to μ-TBS at a cross-speed of 0.5 mm/min. Data were analyzed using one-way ANOVA and Tukey’s test (alpha = .05). Twenty-eight additional teeth were used for interfacial micro-morphologic analysis by SEM (16-teeth) and TEM (12-teeth). The dentin surfaces of 32 discs were treated with the adhesives (8 discs for adhesive) and laminated to form disc-pairs using a flowable resin composite for SEM/EDS analysis. For TEM, 90nm-thick nondemineralized unstained sections were processed. Results: SB2 showed significant higher bond strength than SB, OS and NT. The SEM/EDS and TEM analysis revealed nanofillers infiltrated within the interfibrillar spaces of the SB2-hybrid layer. Fillers were concentrated around patent tubular orifices and in the adhesive layer for OS and NT. Conclusion: The presence of nanofillers within the interfibrillar spaces of the SB2-hybrid layer suggests its importance in the improvement of the μ-TBS. PMID:23077413

  19. Color Stability of Enamel following Different Acid Etching and Color Exposure Times

    PubMed Central

    Jahanbin, Arezoo; Basafa, Mohammad; Moazzami, Mostafa; Basafa, Behnoush; Eslami, Neda

    2014-01-01

    Background and aims. The aim of this study was to evaluate the effect of different etching times on enamel color stability after immediate versus delayed exposure to colored artificial saliva (CAS). Materials and methods. Human first premolars were divided into five groups of twenty. A colorimeter was used according to the CIE system on the mid-buccal and mid-lingual surfaces to evaluate initial tooth color. Samples in group A remained unetched. In groups B to E, buccal and lingual surfaces were initially etched with phosphoric acid for 15 and 60 seconds, respectively. Then, the samples in groups A and C were immersed in colored artificial saliva (cola+saliva). In group B, the teeth were immersed in simple artificial saliva (AS). Samples in groups D and E were immersed in AS for 24 and 72 hours, respectively before being immersed in colored AS. The teeth were immersed for one month in each solution before color measurement. During the test period, the teeth were retrieved from the staining solution and stored in AS for five minutes. This was repeated 60 times. Color changes of buccal and lingual surfaces were calculated. Kruskal-Wallis and Wilcoxon tests were used for statistical analysis (α ≤0.05). Results. There were no significant differences between the groups in term of ΔE of buccal (P = 0.148) and lingual surfaces (P = 0.73). Conclusion. Extended time of etching did not result in significant enamel color change. Immediate and delayed exposure of etched enamel to staining solutions did not result in clinically detectable tooth color changes. PMID:25093048

  20. Characterization and adsorption properties of diatomaceous earth modified by hydrofluoric acid etching.

    PubMed

    Tsai, Wen-Tien; Lai, Chi-Wei; Hsien, Kuo-Jong

    2006-05-15

    This work was a study of the chemical modification of diatomaceous earth (DE) using hydrofluoric acid (HF) solution. Under the experimental conditions investigated, it was found that HF under controlled conditions significantly etched inward into the interior of the existing pore structure in the clay mineral due to its high content of silica, leaving a framework possessing a larger BET surface area (ca. 10 m2 g(-1)) in comparison with that (ca. 4 m2 g(-1)) of its precursor (i.e., DE). Further, the results indicated that the HF concentration is a more determining factor in creating more open pores than other process parameters (temperature, holding time, and solid/liquid ratio). This observation was also in close agreement with the examinations by the silicon analysis, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption kinetics and the adsorption isotherm of methylene blue onto the resulting clay adsorbent can be well described by a pseudo-second-order reaction model and the Freundlich model, respectively.

  1. Synthesis of anatase titanium dioxide nanocaps via hydrofluoric acid etching towards enhanced photocatalysis

    SciTech Connect

    Ding, Kun; Wang, Dan; Yang, Ping; Cheng, Xin

    2016-02-15

    Graphical abstract: Anatase TiO{sub 2} nanocaps prepared by HF-assisted chemical etching method exhibit enhanced photocatalytic activity compared with commercial P25 because of HF served as an etching agent to remove doped impurities. - Highlights: • Anatase TiO{sub 2} nanocaps were synthesized by HF etching process. • The optimal conditions of experiment are 700 °C calcination and 0.2 mL HF solution. • The photocatalytic properties was studied upon UV and Visible irradiation. • The unique TiO{sub 2} nanocaps structure shows excellent photocatalytic activity. - Abstract: Anatase titanium dioxide (TiO{sub 2}) nanocaps were created via a four-step process including the preparation of SiO{sub 2} spheres, the deposition of a TiO{sub 2} layer to fabricate SiO{sub 2}@TiO{sub 2} composite spheres, the calcination for obtaining the crystal structure of anatase phase, and hydrofluoric acid (HF) etching to dissolve SiO{sub 2} cores. The SiO{sub 2}@TiO{sub 2} spheres calcined at 700 °C revealed fine photocatalytic activity. Interestingly, most of samples transformed into TiO{sub 2} nanocaps via HF etching, and TiO{sub 2} nanocaps prepared using optimal conditions exhibited quick degradation (k is 0.052 min{sup −1}) compared with commercial P25 (k is 0.030 min{sup −1}) and the TiO{sub 2} nanostructures etched by a NaOH solution. The excellent photocatalytic performance is attributed to its unique hollow hemispherical nanocaps structure, which is in favor of making full use of incident light. The photocatalysis phenomenon in visible light was also observed after depositing Au nanoparticles on anantase TiO{sub 2} nanocaps.

  2. Double Eclipsing Binary Fitting

    NASA Astrophysics Data System (ADS)

    Cagas, P.; Pejcha, O.

    2012-06-01

    The parameters of the mutual orbit of eclipsing binaries that are physically connected can be obtained by precision timing of minima over time through light travel time effect, apsidal motion or orbital precession. This, however, requires joint analysis of data from different sources obtained through various techniques and with insufficiently quantified uncertainties. In particular, photometric uncertainties are often underestimated, which yields too small uncertainties in minima timings if determined through analysis of a χ2 surface. The task is even more difficult for double eclipsing binaries, especially those with periods close to a resonance such as CzeV344, where minima get often blended with each other. This code solves the double binary parameters simultaneously and then uses these parameters to determine minima timings (or more specifically O-C values) for individual datasets. In both cases, the uncertainties (or more precisely confidence intervals) are determined through bootstrap resampling of the original data. This procedure to a large extent alleviates the common problem with underestimated photometric uncertainties and provides a check on possible degeneracies in the parameters and the stability of the results. While there are shortcomings to this method as well when compared to Markov Chain Monte Carlo methods, the ease of the implementation of bootstrapping is a significant advantage.

  3. Firewalls from double purity

    NASA Astrophysics Data System (ADS)

    Bousso, Raphael

    2013-10-01

    The firewall paradox is often presented as arising from double entanglement, but I argue that more generally the paradox is double purity. Near-horizon modes are purified by the interior, in the infalling vacuum. Hence, they cannot also be pure alone, or in combination with any third system, as demanded by unitarity. This conflict arises independently of the Page time, for entangled and for pure states. It implies that identifications of Hilbert spaces cannot resolve the paradox. Traditional complementarity requires the unitary identification of infalling matter with a scrambled subsystem of the Hawking radiation. Extending this map to the infalling vacuum overdetermines the out-state. More general complementarity maps (“A=RB,” “ER=EPR”) necessarily fail when the near-horizon zone is pure. I argue that pure-zone states span the microcanonical ensemble, and that this suffices to make the horizon a special place. I advocate that the ability to detect the horizon locally, rather than the degree or probability of violence, is what makes firewalls problematic. Conversely, if the production of matter at the horizon can be dynamically understood and shown to be consistent, then firewalls do not constitute a violation of the equivalence principle.

  4. Apple Valley Double Star Workshop

    NASA Astrophysics Data System (ADS)

    Brewer, Mark

    2015-05-01

    The High Desert Astronomical Society hosts an annual double star workshop, where participants measure the position angles and separations of double stars. Following the New Generation Science Standards (NGSS), adopted by the California State Board of Education, participants are assigned to teams where they learn the process of telescope set-up and operation, the gathering of data, and the reduction of the data. Team results are compared to the latest epoch listed in the Washington Double Star Catalog (WDS) and papers are written for publication in the Journal of Double Star Observations (JDSO). Each team presents a PowerPoint presentation to their peers about actual hands-on astronomical research.

  5. Colored Flag by Double Refraction.

    ERIC Educational Resources Information Center

    Reid, Bill

    1994-01-01

    Describes various demonstrations that illustrate double refraction and rotation of the plane of polarization in stressed, transparent plastics, with the consequent production of colored designs. (ZWH)

  6. Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Fiorini, Ettore

    2007-06-01

    The recent results showing the presence of neutrino oscillations clearly indicate that the difference between the squared mass of neutrinos of different flavors is different from zero, but are unable to determine the nature and the absolute value of the neutrino mass. Neutrinoless double beta decay (DBD) is at present the most powerful tool to ascertain if the neutrino is a Majorana particle and to determine under this condition the absolute value of its mass. The results already obtained in this lepton violating process will be reported and the two presently running DBD experiments briefly discussed. The future second generation experiments will be reviewed with special emphasis to those already partially approved. In conclusion the peculiar and interdisciplinary nature of these searches will be stressed in their exciting aim to discover if neutrino is Dirac or Majorana particle.

  7. Double beta decay: Calorimeters

    NASA Astrophysics Data System (ADS)

    Brofferio, Chiara

    2008-11-01

    Calorimeters or, with a more specific definition, low temperature detectors, have been used by now for more than 15 years in Double Beta Decay (DBD) searches, with excellent results: they compete with Ge diodes for the rank of detectors with the highest sensitivity to the effective neutrino mass, which is defined as a linear combination of the neutrino mass eigenvalues. After a brief introduction to the argument, with some notes on DBD and on bolometers, an update on the now closed experiment CUORICINO and on its successor, CUORE, is given. The fundamental role of background is then revealed and commented, introducing in this way the importance of the specific experiment now under construction, CUORE-0, that will precede CUORE to help optimizing the struggle against surface background. The possible future of this technique is then commented, quoting important R&D studies that are going on, for active shielding bolometers and for scintillating bolometers coupled with light detecting bolometers.

  8. Double integrated laser interferometer

    NASA Astrophysics Data System (ADS)

    Motyka, Zbigniew

    2003-10-01

    The layout of integrated optical system compromising the basis of proposed solution of double laser interferometer composed of two integrated Michelson's interferometers is presented and shortly discussed. Such an integrated system is designed for work with two lasers of different wavelength. It may serve for mapping surfaces and deformations of objects under investigation with the use of simultaneous recording of two mutually orthogonal gratings, each one composed of equidistant, parallel interference fringes projected onto the surface of such an object. The picture resulting two-coloured is recorded with the digital camera and may be used for obtaining these maps and deformations directly or in the indirect way after suitable digital processing applied to each colour component separately.

  9. Empirically Unbinding the Double Bind.

    ERIC Educational Resources Information Center

    Olson, David H.

    The theoretical concept of the double bind and the possibilities for researching it are discussed. The author has observed that theory and research, which should be reciprocal and mutually beneficial, have been working, as concerns the double bind, at odds with one another. Two approaches to empirically investigating the concept are considered via…

  10. Double valve Implantation

    PubMed Central

    Stassano, Paolo; Mannacio, Vito; Musumeci, Antonino; Golino, Alessandro; Maida, Piero; Ferrigno, Vincenzo; Buonocore, Gaetano; Spampinato, Nicola

    1991-01-01

    From January 1976 through December 1987, 194 patients with a mean age of 43.3 ± 13.7 years (range, 11 to 74 years) underwent double (mitral and aortic) replacement of native valves with 8 types of bioprostheses: Carpentier-Edwards, 127 valves; Hancock, 76 valves; Liotta-Bioimplant, 57 valves; Ionescu-Shiley, 53 valves; Vascor, 27 valves; Carpentier-Edwards Pericardial, 22 valves; Angell-Shiley, 20 valves; and Implamedic, 6 valves. Concomitant cardiac procedures were performed in 25 patients (12.8%). There were 18 operative deaths (9.27%). Our retrospective analysis was restricted to 352 bioprostheses implanted in the 176 patients who survived surgery and were considered at risk for valve tissue failure. The overall cumulative duration of follow-up was 1,174.1 patient-years (range, 1 to 13 years). The durations of follow-up for specific valves were: Carpentier-Edwards, 920.2 valve-years; Hancock, 383.8 valve-years; Liotta-Bioimplant, 310.2 valve-years; Ionescu-Shiley, 357.7 valve-years; Vascor, 131.2 valve-years; Carpentier-Edwards Pericardial, 52.0 valve-years; Angell-Shiley, 167.0 valve-years; and Implamedic, 31.0 valve-years. Thirty patients had thromboembolic accidents, for a linearized incidence of 2.5% per patient-year. At 13 years, the actuarial freedom from thromboembolic accidents was 85.8% ± 10.7%. Nine patients had endocarditis, for a linearized incidence of 0.7% per patient-year. At 13 years, the actuarial freedom from endocarditis was 92.0% ± 1.5%. Twenty-four patients had valve tissue failure, for a cumulative linearized incidence of 1.87% per valve-year. The cumulative actuarial probability of freedom from valve tissue failure was 78.6% ± 3.7% at 10 years and 51.2% ± 10.7% at 13 years. The 24 patients with valve tissue failure all underwent reoperation: 20 of these had double valve replacement, 3 had aortic valve replacement alone, and 1 had mitral valve replacement alone. The mean interval between initial valve implantation and reoperation was

  11. Theory of nonmonotonic double layers

    SciTech Connect

    Kim, K.Y.

    1987-12-01

    A simple graphic method of solving the Vlasov--Poisson system associated with nonlinear eigenvalue conditions for arbitrary potential structures is presented. A general analytic formulation for nonmonotonic double layers is presented and illustrated with some particular closed form solutions. This class of double layers satisfies the time stationary Vlasov--Poisson system while requiring a Sagdeev potential, which is a double-valued function of the physical potential. It follows that any distribution function having a density representation as any integer or noninteger power series of potential can never satisfy the nonmonotonic double-layer boundary conditions. A Korteweg--de Vries-like equation is found showing a relationship among the speed of the nonmonotonic double layer, its scale length, and its degree of asymmetry.

  12. The Visual Double Star Catalogs

    NASA Astrophysics Data System (ADS)

    Mason, Brian D.

    2015-08-01

    In visual double star work, production of the first comprehensive attempt to list all discovered pairs in his accessible sky was prepared by S.W. Burnham in 1906. A double star catalog for the southern hemisphere was prepared by R.T.A. Innes et al. in 1927 and the northern hemisphere catalog was updated by R.G. Aitken and E. Doolittle in 1932. Eventually, this led to Lick Observatory maintaining what became known as the Index Catalogue, an all-sky visual double star database.In 1964, under the aegis of Commission 26, the Lick double star database was transferred to the U.S. Naval Observatory where it was redesignated the Washington Double Star Catalog where it and it's ancillary catalogs, have been maintained for over half a century. The current statistics of the catalog and it's supplements are presented as are the enhancements currently under consideration.

  13. Antarctic radiation exposure doubles

    NASA Astrophysics Data System (ADS)

    Blue, Charles

    New data reveal that the Antarctic Peninsula received twice its normal maximum dose of hazardous solar ultraviolet radiation in December 1990. The prolonged persistence of the ozone hole over Antarctica caused an increased exposure of radiation, according to a paper published in the October issue of Geophysical Research Letters.John Frederick and Amy D. Alberts of the University of Chicago calculated the amount of ultraviolet solar spectral radiation from data collected at Palmer Station, Antarctica. During the spring of 1990 the largest observed values for ultraviolet radiation were approximately double the values expected, based on previous years. “The measurements from Palmer Station are consistent with similar data from McMurdo Sound, where a factor of three [ultraviolet radiation] enhancement was recorded, according to work by Knut Stamnes and colleagues at the University of Alaska,” Frederick said. “The radiation levels observed over Palmer Station in December 1990 may be the largest experienced in this region of the world since the development of the Earth's ozone layer,” he added.

  14. Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Fiorini, Ettore

    2010-12-01

    Almost exactly seventy years ago and only one year before his tragic disappearance the ingenious idea of Ettore Majorana is becoming one of the most important step in the development of fundamental physics. The problem of the nature of the neutrino, namely if it is a massless Dirac particle different from its antineutrino or a Majorana particle with finite mass, is discussed. In fact the recent results showing the presence of neutrino oscillations clearly indicates that the difference between the squared mass of neutrinos of different flavours is finite. Neutrinoless double beta decay (DBD) is at present the most powerful tool to determine the effective value of the mass of a Majorana neutrino. The results already obtained in this lepton violating process will be reported and the two presently running DBD experiments briefly discussed. The future second generation experiments will be reviewed with special emphasis to those already at least partially approved. In conclusion the peculiar and interdisciplinary nature of these searches will be stressed in their exciting aim to discover if neutrino is indeed a Majorana particle.

  15. Double Diffusive Plumes

    NASA Astrophysics Data System (ADS)

    Sutherland, Bruce; Lee, Brace

    2008-11-01

    Sour gas flares attempt to dispose of deadly H2S gas through combustion. What does not burn rises as a buoyant plume. But the gas is heavier than air at room temperature, so as the rising gas cools eventually it becomes negatively buoyant and descends back to the ground. Ultimately, our intent is to predict the concentrations of the gas at ground level in realistic atmospheric conditions. As a first step towards this goal we have performed laboratory experiments examining the structure of a steady state plume of hot and salty water that rises buoyantly near the source and descends as a fountain after it has cooled sufficiently. We call this a double-diffusive plume because its evolution is dictated by the different (turbulent) diffusivities of heat and salt. A temperature and conductivity probe measures both the salinity and temperature along the centreline of the plume. The supposed axisymmetric structure of the salinity concentration as it changes with height is determined by light-attenuation methods. To help interpret the results, a theory has been successfully adapted from the work of Bloomfield and Kerr (2000), who developed coupled equations describing the structure of fountains. Introducing a new empirical parameter for the relative rates of turbulent heat and salt diffusion, the predictions are found to agree favourably with experimental results.

  16. Double acting bit holder

    DOEpatents

    Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

    1994-01-01

    A double acting bit holder that permits bits held in it to be resharpened during cutting action to increase energy efficiency by reducing the amount of small chips produced. The holder consist of: a stationary base portion capable of being fixed to a cutter head of an excavation machine and having an integral extension therefrom with a bore hole therethrough to accommodate a pin shaft; a movable portion coextensive with the base having a pin shaft integrally extending therefrom that is insertable in the bore hole of the base member to permit the moveable portion to rotate about the axis of the pin shaft; a recess in the movable portion of the holder to accommodate a shank of a bit; and a biased spring disposed in adjoining openings in the base and moveable portions of the holder to permit the moveable portion to pivot around the pin shaft during cutting action of a bit fixed in a turret to allow front, mid and back positions of the bit during cutting to lessen creation of small chip amounts and resharpen the bit during excavation use.

  17. Laser double Doppler flowmeter

    NASA Astrophysics Data System (ADS)

    Poffo, L.; Goujon, J.-M.; Le Page, R.; Lemaitre, J.; Guendouz, M.; Lorrain, N.; Bosc, D.

    2014-05-01

    The Laser Doppler flowmetry (LDF) is a non-invasive method for estimating the tissular blood flow and speed at a microscopic scale (microcirculation). It is used for medical research as well as for the diagnosis of diseases related to circulatory system tissues and organs including the issues of microvascular flow (perfusion). It is based on the Doppler effect, created by the interaction between the laser light and tissues. LDF measures the mean blood flow in a volume formed by the single laser beam, that penetrate into the skin. The size of this measurement volume is crucial and depends on skin absorption, and is not directly reachable. Therefore, current developments of the LDF are focused on the use of always more complex and sophisticated signal processing methods. On the other hand, laser Double Doppler Flowmeter (FL2D) proposes to use two laser beams to generate the measurement volume. This volume would be perfectly stable and localized at the intersection of the two laser beams. With FL2D we will be able to determine the absolute blood flow of a specific artery. One aimed application would be to help clinical physicians in health care units.

  18. A double-loop tracking system.

    NASA Technical Reports Server (NTRS)

    Yuen, J. H.

    1972-01-01

    A nonlinear analysis which can be used to assess certain statistical characteristics of double-loop tracking systems is presented. It takes into account the mutual coupling effects of the loops in the system. Two approaches are taken to obtain steady-state probability density functions (pdf's) of the system phase errors. From these pdf's, important system performance statistics, e.g., the phase-error variances, can be calculated, thus illustrating the application and usefulness of the analysis. The analysis is applied to a satellite transponder as an example.

  19. The Double Chooz Outer Veto

    NASA Astrophysics Data System (ADS)

    Toups, Matthew

    2009-05-01

    Measuring a non-zero value for the neutrino mixing angle θ13 sets the scale for future precision measurements in the lepton sector such as CP violation. The Double Chooz experiment will begin taking data later this year with a sensitivity to 2̂(2θ13) in the 0.02 - 0.03 range, improving on the CHOOZ bound by about an order of magnitude. Efficient rejection of backgrounds induced by cosmic muons is essential to achieving this sensitivity. The Double Chooz Outer Veto plays a crucial role in vetoing and tagging these muons. An update on the status of the Double Chooz Outer Veto will be presented.

  20. Aspects of the doubled worldsheet

    NASA Astrophysics Data System (ADS)

    Driezen, Sibylle; Sevrin, Alexander; Thompson, Daniel C.

    2016-12-01

    We clarify the relation between various approaches to the manifestly T-duality symmetric string. We explain in detail how the PST covariant doubled string arises from an unusual gauge fixing. We pay careful attention to the role of "spectator" fields in this process and also show how the T-duality invariant doubled dilaton emerges naturally. We extend these ideas to non-Abelian T-duality and show they give rise to the duality invariant formalism based on the semi-Abelian Drinfeld Double. We then develop the N = (0, 1) supersymmetric duality invariant formalism.

  1. Double Shell Tanks (DST) and Waste Feed Delivery Project Management Quality Affecting Procedures Management Plan

    SciTech Connect

    LUND, D.P.

    2000-09-25

    The purpose of the Double Shell Tanks (DST) and Waste Feed Delivery (WFD) Management Assessment Plan is to define how management assessments within DST h WFD will be conducted. The plan as written currently includes only WFD Project assessment topics. Other DST and WFD group assessment topics will be added in future revisions.

  2. Double-Base Binder Improvement

    DTIC Science & Technology

    The general objective of this program is to improve the mechanical properties of composite modified double base ( CMDB ) propellants, with particular emphasis upon those prepared by the slurry cast process.

  3. Entanglement purification with double selection

    SciTech Connect

    Fujii, Keisuke; Yamamoto, Katsuji

    2009-10-15

    We investigate an entanglement purification protocol with double-selection process, which works under imperfect local operations. Compared with the usual protocol with single selection, this double-selection method has higher noise thresholds for the local operations and quantum communication channels and achieves higher fidelity of purified states. It also provides a yield comparable to that of the usual protocol with single selection. We discuss on general grounds how some of the errors which are introduced by local operations are left as intrinsically undetectable. The undetectable errors place a general upper bound on the purification fidelity. The double selection is a simple method to remove all the detectable errors in the first order, so that the upper bound on the fidelity is achieved in the low-noise regime. The double selection is further applied to purification of multipartite entanglement such as two-colorable graph states.

  4. [The double and his theatre].

    PubMed

    Trillet, M

    1996-01-01

    Professor Paul Girard dedicated an important part of his scientific works to the notion of the Double. He was naturally prompted to such an investigation because of his interest in lateralization disorders and in the problems of cerebral functional asymmetry. We present his conception, in view of recent information of modern neuropsychology as regards identification and recognition processes, as well as anticipation and familiarity operations. Beyond the problem of the Double, the search for Identity is considered in artistic and literary activity.

  5. Differences in quantification of DNA double-strand breaks assessed by 53BP1/γH2AX focus formation assays and the comet assay in mammalian cells treated with irradiation and N-acetyl-L-cysteine.

    PubMed

    Kurashige, Tomomi; Shimamura, Mika; Nagayama, Yuji

    2016-06-01

    The biological effect of ionizing radiation (IR) on genomic DNA is thought to be either direct or indirect; the latter is mediated by IR induction of free radicals and reactive oxygen species (ROS). This study was designed to evaluate the effect of N-acetyl-L-cysteine (NAC), a well-known ROS-scavenging antioxidant, on IR induction of genotoxicity, cytotoxicity and ROS production in mammalian cells, and aimed to clarify the conflicting data in previous publications. Although we clearly demonstrate the beneficial effect of NAC on IR-induced genotoxicity and cytotoxicity (determined using the micronucleus assay and cell viability/clonogenic assays), the data on NAC's effect on DNA double-strand break (DSB) formation were inconsistent in different assays. Specifically, mitigation of IR-induced DSBs by NAC was readily detected by the neutral comet assay, but not by the γH2AX or 53BP1 focus assays. NAC is a glutathione precursor and exerts its effect after conversion to glutathione, and presumably it has its own biological activity. Assuming that the focus assay reflects the biological responses to DSBs (detection and repair), while the comet assay reflects the physical status of genomic DNA, our results indicate that the comet assay could readily detect the antioxidant effect of NAC on DSB formation. However, NAC's biological effect might affect the detection of DSB repair by the focus assays. Our data illustrate that multiple parameters should be carefully used to analyze DNA damage when studying potential candidates for radioprotective compounds.

  6. Assessment of an updated double-vasopressor automated system using Nexfin for the maintenance of haemodynamic stability to improve peri-operative outcome during spinal anaesthesia for caesarean section.

    PubMed

    Sng, B L; Wang, H; Assam, P N; Sia, A T

    2015-06-01

    Hypotension occurs commonly during spinal anaesthesia for caesarean section, associated with maternal and fetal adverse effects. We developed a double-vasopressor automated system with a two-step algorithm and continuous non-invasive haemodynamic monitoring using the Nexfin device. The system delivered 25 μg phenylephrine every 30 s when systolic blood pressure was between 90% and 100% of baseline, or 2 mg ephedrine at this blood pressure range and heart rate < 60 beats.min(-1) ; and 50 μg phenylephrine or 4 mg ephedrine when systolic blood pressure was < 90% of baseline with the same heart rate criterion. Fifty-seven women received standardised spinal anaesthesia. Twenty-seven (47.4%) had at least one reading of hypotension defined as systolic blood pressure < 80% baseline. Systolic blood pressure was within 20% of the baseline in a mean (SD) of 79.8 (20.9)% of measurements. Fifty-three (93.0%) women required phenylephrine before delivery while 10 (17.5%) required ephedrine. Six women (10.5%) experienced nausea and three (5.3%) vomited. The system was able to achieve a low incidence of maternal hypotension with good maternal and fetal outcomes.

  7. Double metric, generalized metric, and α' -deformed double field theory

    NASA Astrophysics Data System (ADS)

    Hohm, Olaf; Zwiebach, Barton

    2016-03-01

    We relate the unconstrained "double metric" of the "α' -geometry" formulation of double field theory to the constrained generalized metric encoding the spacetime metric and b -field. This is achieved by integrating out auxiliary field components of the double metric in an iterative procedure that induces an infinite number of higher-derivative corrections. As an application, we prove that, to first order in α' and to all orders in fields, the deformed gauge transformations are Green-Schwarz-deformed diffeomorphisms. We also prove that to first order in α' the spacetime action encodes precisely the Green-Schwarz deformation with Chern-Simons forms based on the torsionless gravitational connection. This seems to be in tension with suggestions in the literature that T-duality requires a torsionful connection, but we explain that these assertions are ambiguous since actions that use different connections are related by field redefinitions.

  8. A randomized, double-blind, placebo-controlled, cross-over study to assess the efficacy of tadalafil (Cialis[reg]) in the treatment of erectile dysfunction following three-dimensional conformal external-beam radiotherapy for prostatic carcinoma

    SciTech Connect

    Incrocci, Luca . E-mail: l.incrocci@erasmusmc.nl; Slagter, Cleo; Slob, A. Koos; Hop, Wim C.J.

    2006-10-01

    Purpose: Erectile dysfunction after three-dimensional conformal external-beam radiotherapy (3DCRT) for prostatic carcinoma is reported in as many as 64% of those patients. The purpose of this study was to determine the efficacy of the oral drug tadalafil (Cialis (registered) ) in patients with erectile dysfunction after radiotherapy for prostatic carcinoma. Methods and Materials: Patients (N = 358) who completed radiotherapy at least 12 months before the study were approached by mail. All patients had been treated by 3DCRT; 60 patients were included and entered a double-blind, placebo-controlled, cross-over study lasting 12 weeks. They received 20 mg of tadalafil or placebo for 6 weeks. Drug or placebo was taken on demand at patient's discretion, with no restrictions regarding the consumption of alcohol or food, at least once a week and no more than once daily. At 6 weeks patients crossed over to the alternative treatment. Data were collected using the Sexual Encounter Profile (SEP) and the International Index of Erectile Function (IIEF) questionnaires. Side effects were also recorded. Results: Mean age at study entry was 69 years. All patients completed the study. For almost all questions of the IIEF questionnaire there was a significant increase in mean scores from baseline with tadalafil, but not with placebo. Sixty-seven percent of the patients reported an improvement of erectile function with tadalafil (placebo: 20%), and 48% reported successful intercourse with tadalafil (placebo: 9%) (p < 0.0001). Side effects were mild or moderate. Conclusions: Tadalafil is an effective treatment for erectile dysfunction after 3DCRT for prostatic carcinoma with successful intercourse reported in almost 50% of the patients, and it is well tolerated.

  9. Double shrinking sparse dimension reduction.

    PubMed

    Zhou, Tianyi; Tao, Dacheng

    2013-01-01

    Learning tasks such as classification and clustering usually perform better and cost less (time and space) on compressed representations than on the original data. Previous works mainly compress data via dimension reduction. In this paper, we propose "double shrinking" to compress image data on both dimensionality and cardinality via building either sparse low-dimensional representations or a sparse projection matrix for dimension reduction. We formulate a double shrinking model (DSM) as an l(1) regularized variance maximization with constraint ||x||(2)=1, and develop a double shrinking algorithm (DSA) to optimize DSM. DSA is a path-following algorithm that can build the whole solution path of locally optimal solutions of different sparse levels. Each solution on the path is a "warm start" for searching the next sparser one. In each iteration of DSA, the direction, the step size, and the Lagrangian multiplier are deduced from the Karush-Kuhn-Tucker conditions. The magnitudes of trivial variables are shrunk and the importances of critical variables are simultaneously augmented along the selected direction with the determined step length. Double shrinking can be applied to manifold learning and feature selections for better interpretation of features, and can be combined with classification and clustering to boost their performance. The experimental results suggest that double shrinking produces efficient and effective data compression.

  10. New double soft emission theorems

    NASA Astrophysics Data System (ADS)

    Cachazo, Freddy; He, Song; Yuan, Ellis Ye

    2015-09-01

    We study the behavior of the tree-level S-matrix of a variety of theories as two particles become soft. By analogy with the recently found subleading soft theorems for gravitons and gluons, we explore subleading terms in double soft emissions. We first consider double soft scalar emissions and find subleading terms that are controlled by the angular momentum operator acting on hard particles. The order of the subleading theorems depends on the presence or not of color structures. Next we obtain a compact formula for the leading term in a double soft photon emission. The theories studied are a special Galileon, Dirac-Born-Infeld, Einstein-Maxwell-Scalar, nonlinear sigma model and Yang-Mills-Scalar. We use the recently found Cachazo-He-Yuan representation of these theories in order to give a simple proof of the leading order part of all these theorems.

  11. Double field theory inspired cosmology

    SciTech Connect

    Wu, Houwen; Yang, Haitang E-mail: hyanga@scu.edu.cn

    2014-07-01

    Double field theory proposes a generalized spacetime action possessing manifest T-duality on the level of component fields. We calculate the cosmological solutions of double field theory with vanishing Kalb-Ramond field. It turns out that double field theory provides a more consistent way to construct cosmological solutions than the standard string cosmology. We construct solutions for vanishing and non-vanishing symmetry preserving dilaton potentials. The solutions assemble the pre- and post-big bang evolutions in one single line element. Our results show a smooth evolution from an anisotropic early stage to an isotropic phase without any special initial conditions in contrast to previous models. In addition, we demonstrate that the contraction of the dual space automatically leads to both an inflation phase and a decelerated expansion of the ordinary space during different evolution stages.

  12. DNA double-strand break repair in a cellular context.

    PubMed

    Shibata, A; Jeggo, P A

    2014-05-01

    Substantial insight into the mechanisms responding to DNA double-strand breaks has been gained from molecular, biochemical and structural approaches. Attention is now focusing on understanding the interplay between the pathways, how they interface through the cell cycle and the communication with other DNA transactions, such as replication and transcription. Understanding these aspects will facilitate an assessment of how cancer cells have modified these processes to achieve unlimited proliferative capacity and adaptability, and pave the way to identify targets suitable for therapy. Here, we briefly overview the processes responding to double-strand breaks and discuss our current understanding of their interplay in a cellular context.

  13. Double stranded nucleic acid biochips

    DOEpatents

    Chernov, Boris; Golova, Julia

    2006-05-23

    This invention describes a new method of constructing double-stranded DNA (dsDNA) microarrays based on the use of pre-synthesized or natural DNA duplexes without a stem-loop structure. The complementary oligonucleotide chains are bonded together by a novel connector that includes a linker for immobilization on a matrix. A non-enzymatic method for synthesizing double-stranded nucleic acids with this novel connector enables the construction of inexpensive and robust dsDNA/dsRNA microarrays. DNA-DNA and DNA-protein interactions are investigated using the microarrays.

  14. Double-negative acoustic metamaterial.

    PubMed

    Li, Jensen; Chan, C T

    2004-11-01

    We show here the existence of acoustic metamaterial, in which both the effective density and bulk modulus are simultaneously negative, in the true and strict sense of an effective medium. Our double-negative acoustic system is an acoustic analogue of Veselago's medium in electromagnetism, and shares many unique consequences, such as negative refractive index. The double negativity in acoustics is derived from low-frequency resonances, as in the case of electromagnetism, but the negative density and modulus are derived from a single resonance structure as distinct from electromagnetism in which the negative permeability and negative permittivity originates from different resonance mechanisms.

  15. Current driven weak double layers

    NASA Technical Reports Server (NTRS)

    Chanteur, Gerard

    1987-01-01

    Double layers in plasmas can be created by different means. For example, a potential difference forms between two plasmas with different temperatures, in a plasma jet flowing along a converging magnetic field, in a quiescent plasma submitted to an external difference of potential, or in a turbulent plasma carrying an electric charge. The first three cases can be current-free, but not necessarily, although the numerical simulations were made under such conditions for the first two points. Apart from the third case, which is mainly of interest for laboratory experiments, these double layers are good candidates for accelerating the auroral electrons to the few kiloelectron volts observed.

  16. Double trisomy in spontaneous abortions.

    PubMed

    Reddy, K S

    1997-12-01

    Cytogenetic data on products of conception from spontaneous abortions studied over a 10-year period have been reviewed for double trisomies. A total of 3034 spontaneous abortions were karyotyped between 1986 and 1997. Twenty-two cases with double trisomy, one case with triple trisomy, and a case with a trisomy and monosomy were found. The tissues studied were mostly sac, villi, or placenta. The gestational age ranged from 6 to 11 weeks and the mean age was 8.2 +/- 1.7 (SD) weeks. The mean maternal age in years was 35.9 +/- 5.3. Of the twenty-two cases, four were mosaics. All but two of the cases involved autosomal aneuploidies. The double trisomies included chromosomes 2, 4, 5, 7, 8, 12, 13, 14, 15, 16, 17, 18, 20, 21, and 22. The chromosomes that were trisomic in more than one double trisomy case were numbers 16 (8 cases), 8 (5 cases), 15 (4 cases), 2, 13, and 21 (3 cases each), and 5, 7, 14, 18, 20, 22, and X (2 cases). The triple trisomy involved chromosomes 18, 21, and X. The monosomy and trisomy case was a mosaic, with a monosomy 21 in all cells and some cells also with a trisomy 5. The double trisomies cited for the first time in this study were 4/13, 5/16, 8/14, 8/15, 14/21, 15/20, and 7/12. The pooled mean maternal age for double trisomy cases (34.1 +/- 5.7 years) was higher than that for single trisomy cases (31 +/- 6.1 years). The difference was statistically significant at P = < 0.001. The pooled mean gestational age of spontaneous abortions was lower for double trisomy (8.7 +/- 2.2 weeks) than for reported single trisomy cases (10.1 +/- 2.9 weeks). This difference is also statistically significant at P = < 0.001. The sex ratio among double trisomies was 15 females to 13 males. This difference was not statistically significant from the expected 1:1.

  17. A double-sided linear primary permanent magnet vernier machine.

    PubMed

    Du, Yi; Zou, Chunhua; Liu, Xianxing

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed.

  18. A Double-Sided Linear Primary Permanent Magnet Vernier Machine

    PubMed Central

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed. PMID:25874250

  19. Evaluation of remaining life of the double-shell tank waste systems

    SciTech Connect

    Schwenk, E.B.

    1995-05-04

    A remaining life assessment of the DSTs (double-shell tanks) and their associated waste transfer lines, for continued operation over the next 10 years, was favorable. The DST assessment was based on definition of significant loads, evaluation of data for possible material degradation and geometric changes and evaluation of structural analyses. The piping assessment was based primarily on service experience.

  20. The double well mass filter

    DOE PAGES

    Gueroult, Renaud; Rax, Jean -Marcel; Fisch, Nathaniel J.

    2014-02-03

    Various mass filter concepts based on rotating plasmas have been suggested with the specific purpose of nuclear waste remediation. We report on a new rotating mass filter combining radial separation with axial extraction. Lastly, the radial separation of the masses is the result of a “double-well” in effective radial potential in rotating plasma with a sheared rotation profile.

  1. A Double-Minded Fractal

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2009-01-01

    This article presents a fun activity of generating a double-minded fractal image for a linear algebra class once the idea of rotation and scaling matrices are introduced. In particular the fractal flip-flops between two words, depending on the level at which the image is viewed. (Contains 5 figures.)

  2. Natural products: DNA double whammy

    NASA Astrophysics Data System (ADS)

    Gates, Kent S.

    2014-06-01

    The lomaiviticins are exceedingly potent antibiotic agents, but the mechanism responsible for this activity has so far been unclear. Now, efficient generation of double-strand breaks in DNA by lomaiviticin A has been linked to the remarkable cytotoxicity of these diazobenzofluorene-containg natural products.

  3. Double spaces with isolated singularities

    SciTech Connect

    Cheltsov, I A

    2008-02-28

    The non-rationality is proved for double covers of P{sup n} branched over a hypersurface F subset of P{sup n} of degree 2n>=8 with isolated singularities such that the multiplicity of each singular point of F does not exceed 2(n-2) and the projectivization of its tangent cone is smooth. Bibliography: 15 titles.

  4. Keepers of the double stars

    NASA Astrophysics Data System (ADS)

    Tenn, Joseph S.

    2013-03-01

    Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Early catalogues by the Herschels, Struves, and others began with their own discoveries. In 1906 court reporter and amateur astronomer Sherburne Wesley Burnham published a massive double star catalogue containing data from many observers on more than 13,000 systems. Lick Observatory astronomer Robert Grant Aitken produced a much larger catalogue in 1932 and coordinated with Robert Innes of Johannesburg, who catalogued the southern systems. Aitken maintained and expanded Burnham's records of observations on handwritten file cards, and eventually turned them over to the Lick Observatory, where astrometrist Hamilton Jeffers further expanded the collection and put all the observations on punched cards. With the aid of Frances M. "Rete" Greeby he made two catalogues: an Index Catalogue with basic data about each star, and a complete catalogue of observations, with one observation per punched card. He enlisted Willem van den Bos of Johannesburg to add southern stars, and together they published the Index Catalogue of Visual Double Stars, 1961.0. As Jeffers approached retirement he became greatly concerned about the disposition of the catalogues. He wanted to be replaced by another "double star man," but Lick Director Albert E. Whitford had the new 120-inch reflector, the world's second largest telescope, and he wanted to pursue modern astrophysics instead. Jeffers was vociferously opposed to turning over the card files to another institution, and especially against their coming under the control of Kaj Strand of the United States Naval Observatory. In the end the USNO got the files and has maintained the records ever since, first under Charles Worley, and, since 1997, under Brian Mason. Now called the Washington Double Star Catalog (WDS), it is completely online and currently contains more than 1,200,000 measures of more than 125

  5. A laboratory investigation of potential double layers

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1987-01-01

    In a triple plasma device, the injection of electron current from the source chamber to the target chamber causes the formation of a potential double layer. At a low current density, the space charge of the injected current produces a virtual cathode-type potential double layer. This double layer is stable, and various wave instabilities are observed to associate with this double layer. As the current density is increased, the double layer becomes unstable, and a moving double layer results. As the current density is increased further, the enhanced ionization causes the neutralization of the space charge of the electron beam, and the beam plasma discharge is ignited.

  6. A laboratory investigation of potential double layers

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1987-01-01

    In a triple plasma device, the injection of electron current from the source chamber to the target chamber causes the formation of a potential double layer. At a low current density, the space charge of the injected current produces a virtual cathode-type potential double layer. This double layer is stable and various wave instabilities are observed to associate with this double layer. As the current density is increased, the double layer becomes unstable and a moving double layer results. As the current density is increased further, the enhanced ionization causes the neutralization of the space charge of the electron beam and the 'beam plasma discharge' is ignited.

  7. Double Photoionization into Double Core-Hole States in Xe

    SciTech Connect

    Hikosaka, Y.; Kaneyasu, T.; Shigemasa, E.; Lablanquie, P.; Penent, F.; Eland, J. H. D.; Aoto, T.; Ito, K.

    2007-05-04

    Double photoionization (DPI) leading to double core-hole states of Xe{sup 2+} 4d{sup -2} has been studied using a magnetic bottle time-of-flight spectrometer. The assignments of the Xe{sup 2+} 4d{sup -2} states are confirmed by the Auger lines extracted from fourfold coincidences including two photoelectrons and two Auger electrons. It is estimated that the core-core DPI into Xe{sup 2+} 4d{sup -2} at a photon energy of 301.6 eV has a favored cross section of about 0.3 MB. The intense core-core DPI is due to mixing of the 4d{sup -2} continuum with the 4p single photoionization, which is manifested in the relative intensities of the Xe{sup 2+} 4d{sup -2} components.

  8. Pathways to doubled haploidy: chromosome doubling during androgenesis.

    PubMed

    Seguí-Simarro, J M; Nuez, F

    2008-01-01

    Production of doubled haploid (DH) plants through androgenesis induction is a promising and convenient alternative to conventional selfing techniques for the generation of pure lines for breeding programs. This process comprises two main steps: induction of androgenesis and duplication of the haploid genome. Such duplication is sometimes indirectly induced by the treatments used to promote androgenic development. But usually, an additional step of direct chromosome doubling must be included in the protocol. Duplication of the haploid genome of androgenic individuals has been thought to occur through three mechanisms: endoreduplication, nuclear fusion and c-mitosis. In this review we will revise and analyze the evidences supporting each of the proposed mechanisms and their relevance during androgenesis induction, embryo/callus development and plant regeneration. Special attention will be devoted to nuclear fusion, whose evidences are accumulating in the last years.

  9. Double Standard/Double Bind: The Sexual Double Standard and Women's Communication about Sex.

    ERIC Educational Resources Information Center

    Muehlenhard, Charlene L.; McCoy, Marcia L.

    1991-01-01

    College women (n=403) attending the University of Kansas (Lawrence) commented on situations of refusal of desire for sexual relations when they actually did want them (scripted refusal). Consistent with theories of proximal determinants of gender-related behavior, scripted refusal provides a way of dealing with the sexual double standard. (SLD)

  10. Double layers and double wells in arbitrary degenerate plasmas

    NASA Astrophysics Data System (ADS)

    Akbari-Moghanjoughi, M.

    2016-06-01

    Using the generalized hydrodynamic model, the possibility of variety of large amplitude nonlinear excitations is examined in electron-ion plasma with arbitrary electron degeneracy considering also the ion temperature effect. A new energy-density relation is proposed for plasmas with arbitrary electron degeneracy which reduces to the classical Boltzmann and quantum Thomas-Fermi counterparts in the extreme limits. The pseudopotential method is employed to find the criteria for existence of nonlinear structures such as solitons, periodic nonlinear structures, and double-layers for different cases of adiabatic and isothermal ion fluids for a whole range of normalized electron chemical potential, η0, ranging from dilute classical to completely degenerate electron fluids. It is observed that there is a Mach-speed gap in which no large amplitude localized or periodic nonlinear excitations can propagate in the plasma under consideration. It is further revealed that the plasma under investigation supports propagation of double-wells and double-layers the chemical potential and Mach number ranges of which are studied in terms of other plasma parameters. The Mach number criteria for nonlinear waves are shown to significantly differ for cases of classical with η0 < 0 and quantum with η0 > 0 regimes. It is also shown that the localized structure propagation criteria possess significant dissimilarities for plasmas with adiabatic and isothermal ions. Current research may be generalized to study the nonlinear structures in plasma containing positrons, multiple ions with different charge states, and charged dust grains.

  11. Comparison of the Clinical and Radiological Oucomes of Conventional Double row and Double row Suture Bridge Repairs in Rotator Cuff Tears

    PubMed Central

    Muiño, José María Silberberg; Gimenez, Martín Alejandro; Salvucci, Mauro Gabriel Maroa; Ferro, Diego; Rullan, Ramón Muiña; Blanchero, Pablo

    2017-01-01

    Objectives: To compare clinical and radiological results of two types of rotator cuff (RC) repairs: the double row and double row-suture bridge. Methods: Forty-two patients with a complete tear (medium and large size) of the RC were repaired by a double row arthroscopic technique. Minimum follow-up was 19 months (range, 19-28 months). Clinical outcomes were assessed by the Modified Constant Scale and satisfaction rate by an independent observer; VAS, UCLA and ASES. Radiological results were assed by a postoperative MRI by a musculoskeletal radiologist. Results: Series of 22 patients in the double row technique (Group A) and 20 patients in the double-row suture bridge (Gruop B). Statistically there was a significant improvement in the Constant Scale, satisfaction rate, muscle assessment, VAS, UCLA and ASES in both groups after the surgical procedure. There were no significant clinical differences between both groups at any time after the surgical procedure. According to MRI postop, 19/22 shoulders in Group A and 18/20 in Group B remained intact, with no significant differences between the two groups. Conclusion: RC repairs with double row and double-row-suture bridge techniques provide clinical and radiological good and excelent results. In our retrospective, mid-size study, we have found no differences between these two repair techniques.

  12. Assessment of clinical efficacy and safety in a randomized double-blind study of etanercept and sulfasalazine in patients with ankylosing spondylitis from Eastern/Central Europe, Latin America, and Asia.

    PubMed

    Damjanov, Nemanja; Shehhi, Waleed Al; Huang, Feng; Kotak, Sameer; Burgos-Vargas, Ruben; Shirazy, Khalid; Bananis, Eustratios; Szumski, Annette; Llamado, Lyndon J Q; Mahgoub, Ehab

    2016-05-01

    Despite the demonstrated efficacy of etanercept for the treatment of ankylosing spondylitis (AS), sulfasalazine is often prescribed, especially in countries with limited access to biologic agents. The objective of this subset analysis of the ASCEND trial was to compare the efficacy of etanercept and sulfasalazine in treating patients with AS from Asia, Eastern/Central Europe, and Latin America. A total of 287 patients, 190 receiving etanercept 50 mg once weekly and 97 receiving sulfasalazine 3 g daily, from eight countries were included in this subset analysis. Differences in disease activity and patient-reported outcomes assessing health-related quality-of-life (HRQoL) parameters in response to treatment were analyzed using the Cochran-Mantel-Haenszel test for categorical efficacy endpoints and analysis of covariance model for continuous variables. At week 16, a significantly greater proportion of patients receiving etanercept achieved ASAS20 (79.0 %) compared with patients receiving sulfasalazine (61.9 %; p = 0.002). At week 16, treatment with etanercept also resulted in significantly better responses than sulfasalazine for ASAS40 (64.7 vs. 35.1 %; p < 0.001), ASAS5/6 (48.1 vs. 26.3 %; p < 0.001), proportion of patients achieving 50 % response in Bath AS Disease Activity Index (65.8 vs. 42.3 %; p < 0.001), partial remission (35.3 vs. 17.5 %; p = 0.002), and all HRQoL parameters. Both treatments were well tolerated. Etanercept was significantly more effective than sulfasalazine in the treatment of patients with AS from Asia, Central/Eastern Europe, and Latin America.

  13. Hierarchy in a double braneworld

    SciTech Connect

    Guerrero, Rommel; Rodriguez, R. Omar; Melfo, Alejandra; Pantoja, Nelson

    2006-10-15

    We show that the hierarchy between the Planck and the weak scales can follow from the tendency of gravitons and fermions to localize at different edges of a thick double wall embedded in an AdS{sub 5} spacetime without reflection symmetry. This double wall is a stable BPS thick-wall solution with two subwalls located at its edges; fermions are coupled to the scalar field through Yukawa interactions, but the lack of reflection symmetry forces them to be localized in one of the subwalls. We show that the graviton zero-mode wave function is suppressed in the fermion edge by an exponential function of the distance between the subwalls, and that the massive modes decouple so that Newtonian gravity is recuperated.

  14. Edwards syndrome with double trisomy.

    PubMed

    Tennakoon, J; Kandasamy, Y; Alcock, G; Koh, T H

    2008-07-01

    Double trisomy is rare and the only case reported in the literature died soon after birth. We present another case of double trisomy (48XYY, +18) in a male neonate, who was born to a 28-year-old gravida three parity one mother at 35 weeks of gestation. The baby had features of trisomy 18. Karyotype of the patient showed 48, XYY, +18, Ish (DYZ3*2), (D18Z1*3), nuc ish (DYZ3*2), (D18Z1*3) . The patient had clinical features of trisomy 18. There was no family history of diabetes mellitus and no exposure to chemicals. It has been suggested that the rarity of Y-chromosome involvement in trisomy 18 may be due to discrepancy between the sexes.

  15. Minimal Doubling and Point Splitting

    SciTech Connect

    Creutz, M.

    2010-06-14

    Minimally-doubled chiral fermions have the unusual property of a single local field creating two fermionic species. Spreading the field over hypercubes allows construction of combinations that isolate specific modes. Combining these fields into bilinears produces meson fields of specific quantum numbers. Minimally-doubled fermion actions present the possibility of fast simulations while maintaining one exact chiral symmetry. They do, however, introduce some peculiar aspects. An explicit breaking of hyper-cubic symmetry allows additional counter-terms to appear in the renormalization. While a single field creates two different species, spreading this field over nearby sites allows isolation of specific states and the construction of physical meson operators. Finally, lattice artifacts break isospin and give two of the three pseudoscalar mesons an additional contribution to their mass. Depending on the sign of this mass splitting, one can either have a traditional Goldstone pseudoscalar meson or a parity breaking Aoki-like phase.

  16. Current double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Giuliani, A.

    2005-01-01

    After an introduction about double beta decay and the deep connections between the lepton-violating channel and the neutrino properties, the most sensitive experimental approaches to the search for this rare nuclear transition are described. An overview of the experiments presently running is then given, with particular emphasis on the adopted techniques and their possible extrapolation to next-generation, higher-sensitivity experiments. The present situation about the experimental determination of the Majorana neutrino mass is presented and discussed.

  17. A randomized, double-blind, placebo-controlled trial to assess safety and tolerability during treatment of type 2 diabetes with usual diabetes therapy and either Cycloset™ or placebo

    PubMed Central

    Scranton, Richard E; Gaziano, J Michael; Rutty, Dean; Ezrokhi, Michael; Cincotta, Anthony

    2007-01-01

    Background Cycloset™ is a quick-release formulation of bromocriptine mesylate, a dopamine agonist, which in animal models of insulin resistance and type 2 diabetes acts centrally to reduce resistance to insulin- mediated suppression of hepatic glucose output and tissue glucose disposal. In such animals, bromocriptine also reduces hepatic triglyceride synthesis and free fatty acid mobilization, manifesting decreases in both plasma triglycerides and free fatty acids. In clinical trials, morning administration of Cycloset™ either as monotherapy or adjunctive therapy to sulfonylurea or insulin reduces HbA1c levels relative to placebo by 0.55–1.2. Cycloset™ therapy also reduces plasma triglycerides and free fatty acid by approximately 25% and 20%, respectively, among those also receiving sulfonylurea therapies. The effects of once-daily morning Cycloset™ therapy on glycemic control and plasma lipids are demonstrable throughout the diurnal portion of the day (7 a.m. to 7 p.m.) across postprandial time points. Methods/Design 3,095 individuals were randomized in a 2:1 ratio into a one year trial aimed to assess the safety and efficacy of Cycloset™ compared to placebo among individuals receiving a variety of treatments for type 2 diabetes. Eligibility criteria for this randomized placebo controlled trial included: age 30–80, HbA1c ≤ 10%, diabetes therapeutic regimen consisting of diet or no more than two hypoglycemic agents or insulin with or without one additional oral agent (usual diabetes therapy; UDT). The primary safety endpoint will test the hypothesis that the rate of all-cause serious adverse events after one year of usual diabetes therapy (UDT) plus Cycloset™ is not greater than that for UDT plus placebo by more than an acceptable margin defined as a hazard ratio of 1.5 with a secondary endpoint analysis of the difference in the rate of serious cardiovascular events, (myocardial infarction, stroke, coronary revascularization or hospitalization for

  18. Pair extended coupled cluster doubles

    SciTech Connect

    Henderson, Thomas M.; Scuseria, Gustavo E.; Bulik, Ireneusz W.

    2015-06-07

    The accurate and efficient description of strongly correlated systems remains an important challenge for computational methods. Doubly occupied configuration interaction (DOCI), in which all electrons are paired and no correlations which break these pairs are permitted, can in many cases provide an accurate account of strong correlations, albeit at combinatorial computational cost. Recently, there has been significant interest in a method we refer to as pair coupled cluster doubles (pCCD), a variant of coupled cluster doubles in which the electrons are paired. This is simply because pCCD provides energies nearly identical to those of DOCI, but at mean-field computational cost (disregarding the cost of the two-electron integral transformation). Here, we introduce the more complete pair extended coupled cluster doubles (pECCD) approach which, like pCCD, has mean-field cost and reproduces DOCI energetically. We show that unlike pCCD, pECCD also reproduces the DOCI wave function with high accuracy. Moreover, pECCD yields sensible albeit inexact results even for attractive interactions where pCCD breaks down.

  19. Latest results from Double Chooz

    NASA Astrophysics Data System (ADS)

    Minotti, A.

    2017-01-01

    Double Chooz is a short-baseline neutrino disappearance experiment. It detects ν¯ e produced in the power plant of Chooz, France, where is located. The main goal of the experiment is the measurement of θ13 mixing angle and in 2011 for the first time the experiment observed an indication for a non zero value of such an oscillation parameter. The mixing angle was successively measured using only the far detector finding the best fit value of sin2(2θ13) = 0.090 -0.029 +0.032 . The near detector is under construction and will start data taking by the middle of 2014 allowing the reduction of the systematic errors. In this paper I make a review of the Double Chooz experiment, focusing in particular on the latest results of the measurement of the mixing angle θ13 relying on the neutron absorption on Gadolinium. I also present results proving the capability of Double Chooz to identify the ortho-positronium. This has been done in an event-by-event basis for the first time in a large liquid scintillator experiments, and can be an additional handle for the electron/positron discrimination in future detectors based on such technology.

  20. Revisiting double Dirac delta potential

    NASA Astrophysics Data System (ADS)

    Ahmed, Zafar; Kumar, Sachin; Sharma, Mayank; Sharma, Vibhu

    2016-07-01

    We study a general double Dirac delta potential to show that this is the simplest yet still versatile solvable potential to introduce double wells, avoided crossings, resonances and perfect transmission (T = 1). Perfect transmission energies turn out to be the critical property of symmetric and anti-symmetric cases wherein these discrete energies are found to correspond to the eigenvalues of a Dirac delta potential placed symmetrically between two rigid walls. For well(s) or barrier(s), perfect transmission (or zero reflectivity, R(E)) at energy E=0 is non-intuitive. However, this has been found earlier and called the ‘threshold anomaly’. Here we show that it is a critical phenomenon and we can have 0≤slant R(0)\\lt 1 when the parameters of the double delta potential satisfy an interesting condition. We also invoke a zero-energy and zero curvature eigenstate (\\psi (x)={Ax}+B) of the delta well between two symmetric rigid walls for R(0)=0. We resolve that the resonant energies and the perfect transmission energies are different and they arise differently.

  1. Double-Plate Penetration Equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    2000-01-01

    This report compares seven double-plate penetration predictor equations for accuracy and effectiveness of a shield design. Three of the seven are the Johnson Space Center original, modified, and new Cour-Palais equations. The other four are the Nysmith, Lundeberg-Stern-Bristow, Burch, and Wilkinson equations. These equations, except the Wilkinson equation, were derived from test results, with the velocities ranging up to 8 km/sec. Spreadsheet software calculated the projectile diameters for various velocities for the different equations. The results were plotted on projectile diameter versus velocity graphs for the expected orbital debris impact velocities ranging from 2 to 15 km/sec. The new Cour-Palais double-plate penetration equation was compared to the modified Cour-Palais single-plate penetration equation. Then the predictions from each of the seven double-plate penetration equations were compared to each other for a chosen shield design. Finally, these results from the equations were compared with test results performed at the NASA Marshall Space Flight Center. Because the different equations predict a wide range of projectile diameters at any given velocity, it is very difficult to choose the "right" prediction equation for shield configurations other than those exactly used in the equations' development. Although developed for various materials, the penetration equations alone cannot be relied upon to accurately predict the effectiveness of a shield without using hypervelocity impact tests to verify the design.

  2. Double excitations in finite systems.

    PubMed

    Romaniello, P; Sangalli, D; Berger, J A; Sottile, F; Molinari, L G; Reining, L; Onida, G

    2009-01-28

    Time-dependent density-functional theory (TDDFT) is widely used in the study of linear response properties of finite systems. However, there are difficulties in properly describing excited states, which have double- and higher-excitation characters, which are particularly important in molecules with an open-shell ground state. These states would be described if the exact TDDFT kernel were used; however, within the adiabatic approximation to the exchange-correlation (xc) kernel, the calculated excitation energies have a strict single-excitation character and are fewer than the real ones. A frequency-dependent xc kernel could create extra poles in the response function, which would describe states with a multiple-excitation character. We introduce a frequency-dependent xc kernel, which can reproduce, within TDDFT, double excitations in finite systems. In order to achieve this, we use the Bethe-Salpeter equation with a dynamically screened Coulomb interaction W(omega), which can describe these excitations, and from this we obtain the xc kernel. Using a two-electron model system, we show that the frequency dependence of W does indeed introduce the double excitations that are instead absent in any static approximation of the electron-hole screening.

  3. 7 CFR 51.2846 - Doubles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Doubles. 51.2846 Section 51.2846 Agriculture... Creole Types) Definitions § 51.2846 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  4. 7 CFR 51.3207 - Doubles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Doubles. 51.3207 Section 51.3207 Agriculture... Standards for Grades of Bermuda-Granex-Grano Type Onions Definitions § 51.3207 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  5. 7 CFR 51.3207 - Doubles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Doubles. 51.3207 Section 51.3207 Agriculture... § 51.3207 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  6. 7 CFR 51.3207 - Doubles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Doubles. 51.3207 Section 51.3207 Agriculture... § 51.3207 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  7. 7 CFR 51.2846 - Doubles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Doubles. 51.2846 Section 51.2846 Agriculture... Standards for Grades of Onions (Other Than Bermuda-Granex-Grano and Creole Types) Definitions § 51.2846 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  8. 7 CFR 51.3207 - Doubles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Doubles. 51.3207 Section 51.3207 Agriculture... Standards for Grades of Bermuda-Granex-Grano Type Onions Definitions § 51.3207 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  9. 7 CFR 51.2846 - Doubles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Doubles. 51.2846 Section 51.2846 Agriculture... Standards for Grades of Onions (Other Than Bermuda-Granex-Grano and Creole Types) Definitions § 51.2846 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  10. 7 CFR 51.2846 - Doubles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Doubles. 51.2846 Section 51.2846 Agriculture... Creole Types) Definitions § 51.2846 Doubles. Doubles means onions which have developed more than one distinct bulb joined only at the base....

  11. Optimization of the double dosimetry algorithm for interventional cardiologists

    NASA Astrophysics Data System (ADS)

    Chumak, Vadim; Morgun, Artem; Bakhanova, Elena; Voloskiy, Vitalii; Borodynchik, Elena

    2014-11-01

    A double dosimetry method is recommended in interventional cardiology (IC) to assess occupational exposure; yet currently there is no common and universal algorithm for effective dose estimation. In this work, flexible and adaptive algorithm building methodology was developed and some specific algorithm applicable for typical irradiation conditions of IC procedures was obtained. It was shown that the obtained algorithm agrees well with experimental measurements and is less conservative compared to other known algorithms.

  12. Heat generation in double layer capacitors

    NASA Astrophysics Data System (ADS)

    Schiffer, Julia; Linzen, Dirk; Sauer, Dirk Uwe

    Thermal management is a key issue concerning lifetime and performance of double layer capacitors and battery technologies. Double layer capacitor modules for hybrid vehicles are subject to heavy duty cycling conditions and therefore significant heat generation occurs. High temperature causes accelerated aging of the double layer capacitors and hence reduced lifetime. To investigate the thermal behavior of double layer capacitors, thermal measurements during charge/discharge cycles were performed. These measurements show that heat generation in double layer capacitors is the superposition of an irreversible Joule heat generation and a reversible heat generation caused by a change in entropy. A mathematical representation of both parts is provided.

  13. Melatonin-micronutrients Osteopenia Treatment Study (MOTS): a translational study assessing melatonin, strontium (citrate), vitamin D3 and vitamin K2 (MK7) on bone density, bone marker turnover and health related quality of life in postmenopausal osteopenic women following a one-year double-blind RCT and on osteoblast-osteoclast co-cultures

    PubMed Central

    Maria, Sifat; Swanson, Mark H.; Enderby, Larry T.; D'Amico, Frank; Enderby, Brianna; Samsonraj, Rebekah M.; Dudakovic, Amel; van Wijnen, Andre J.; Witt-Enderby, Paula A.

    2017-01-01

    This one-year double blind randomized control trial assessed the effects of nightly melatonin, strontium (citrate), vitamin D3 and vitamin K2 (MK7; MSDK) on bone mineral density (BMD) and quality of life (QOL) in postmenopausal osteopenic women (ages 49-75). Compared to placebo, MSDK treatment increased BMD in lumbar spine (4.3%) and left femoral neck (2.2%), with an upward trend for total left hip (p=0.069). MSDK increased serum P1NP levels and reduced bone turnover (CTx:P1NP). Psychometric analyses indicated that mood and sleep quality improved for the MSDK group. MSDK-exposed human mesenchymal stem cells (hMSCs) and human peripheral blood monocytes (hPBMCs) plated in transwells or layered demonstrated increases in osteoblastogenesis, decreases in osteoclastogenesis, increases in OPG (TNFRSF11B) and decreases in RANKL (TNFSF11) levels. In transwell osteoblasts, MSDK increased pERK1/2 (MAPK1/MAPK3) and RUNX2 levels; decreased ERK5 (MAPK7); and did not affect the expression of NFκB (NFKB1) and β1integrin (ITGB1). In layered osteoblasts, MSDK also decreased expression of the metabolic proteins PPARγ (PPARG) and GLUT4 (SLC2A4). In adipose-derived human MSCs, MSDK induced osteoblastogenesis. These findings provide both clinical and mechanistic support for the use of MSDK for the prevention or treatment of osteopenia, osteoporosis or other bone-related diseases. PMID:28130552

  14. Simulation of plasma double-layer structures

    NASA Technical Reports Server (NTRS)

    Borovsky, J. E.; Joyce, G.

    1982-01-01

    Electrostatic plasma double layers are numerically simulated by means of a magnetized 2 1/2 dimensional particle in cell method. The investigation of planar double layers indicates that these one dimensional potential structures are susceptible to periodic disruption by instabilities in the low potential plasmas. Only a slight increase in the double layer thickness with an increase in its obliqueness to the magnetic field is observed. Weak magnetization results in the double layer electric field alignment of accelerated particles and strong magnetization results in their magnetic field alignment. The numerical simulations of spatially periodic two dimensional double layers also exhibit cyclical instability. A morphological invariance in two dimensional double layers with respect to the degree of magnetization implies that the potential structures scale with Debye lengths rather than with gyroradii. Electron beam excited electrostatic electron cyclotron waves and (ion beam driven) solitary waves are present in the plasmas adjacent to the double layers.

  15. New insight on double-double radio galaxies

    NASA Astrophysics Data System (ADS)

    Nandi, Sumana

    2016-07-01

    Striking examples of episodic jet activity in active galactic nuclei (AGN) are the double-double radio galaxies (DDRGs) with two pairs of lobes emerging from the same central engine. The number of DDRGs reported so far is very limited, and it is important to identify more of these to provide a significant statistical overview of the conditions to trigger the jets and the role of jets in terms of feedback mechanisms that affect the host galaxies. Although most DDRGs were believed initially to be giant radio sources with sizes more than a Mpc, a significant number of smaller sized candidate DDRGs have also been identified in our recent study. We started GMRT observation of this sample to confirm that the sources are related to distinct epochs of nuclear activity. In addition to this radio observation we have also investigated the properties of the host galaxies and their environments to understand the triggering mechanisms for recurrent jet emission. Here, I will highlight the main results from these observations and discuss on the possible scenarios responsible for the episodic activity in different types of DDRGs .

  16. Enhanced nonlinear susceptibility via double-double electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Alotaibi, Hessa M. M.; Sanders, Barry C.

    2016-11-01

    We investigate the nonlinear optical susceptibility of an alkali-metal atom with tripod electronic configuration responsible for generating cross-phase modulation and self-phase modulation under the condition of double-double electromagnetically induced transparency. Our investigation demonstrates an enhancement in the nonlinear optical susceptibility of an alkali-metal atom by a factor of 1000 in the region of the second transparency window. This enhancement is in comparison with the atom's susceptibility in the first transparency window for the same parameters under the same conditions. Nonlinear-absorption enhancement arises by canceling Raman-gain generation, which arises when the probe and signal fields have equal intensities. At the center of the second transparency window, we obtain the condition required to attain a nonvanishing nonlinear optical susceptibility. In the bare-state picture, the coupling field must be off resonant from a bare-to-bare-state transition, while working in the semiclassical dressed picture required the signal field to be tuned off resonantly with a bare-to-dressed-state transition. The relation that governs the values of coupling- and signal-field detuning are also obtained. Our scheme exhibits the fact that the second transparency window has advantages over the first transparency window with respect to obtaining an enhanced Kerr effect, and our calculation includes simulation of both low-temperature and Doppler-broadened regimes.

  17. Booster Double Harmonic Setup Notes

    SciTech Connect

    Gardner, C. J.

    2015-02-17

    The motivation behind implementing a booster double harmonic include the reduced transverse space charge force from a reduced peak beam current and reduced momentum spread of the beam, both of which can be achieved from flattening the RF bucket. RF capture and acceleration of polarized protons (PP) is first set up in the single harmonic mode with RF harmonic h=1. Once capture and acceleration have been set up in the single harmonic mode, the second harmonic system is brought on and programmed to operate in concert with the single harmonic system.

  18. Human norovirus inactivation in oysters by high hydrostatic pressure processing: A randomized double-blinded study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This randomized, double-blinded, clinical trial assessed the effect of high hydrostatic pressure processing (HPP) on genogroup I.1 human norovirus (HuNoV) inactivation in virus-seeded oysters when ingested by subjects. The safety and efficacy of HPP treatments were assessed in three study phases wi...

  19. Double layers and circuits in astrophysics

    NASA Technical Reports Server (NTRS)

    Alfven, Hannes

    1986-01-01

    As the rate of energy release in a double layer with voltage delta V is P approx I delta V, a double layer must be treated as a part of a circuit which delivers the current I. As neither double layer nor circuit can be derived from magnetofluid models of a plasma, such models are useless for treating energy transfer by means of double layers. They must be replaced by particle models and circuit theory. A simple circuit is suggested which is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the Sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object (one example is the double radio sources). It is tentatively suggested in X-ray and Gamma-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). A study of how a number of the most used textbooks in astrophysics treat important concepts like double layers, critical velocity, pinch effects and circuits is made.

  20. Double-Front Detonation Waves

    NASA Astrophysics Data System (ADS)

    Gubin, S. A.; Sumskoi, S. I.; Victorov, S. B.

    According to the theory of detonation, in a detonation wave there is a sound plane, named Chapman-Jouguet (CJ) plane. There are certain stationary parameters for this plane. In this work the possibility of the second CJ plane is shown. This second CJ plane is stationary as well. The physical mechanism of non-equilibrium transition providing the existence of the second CJ plane is presented. There is a non-equilibrium state, when the heat is removed from the reaction zone and the heat capacity decreases sharply. As a result of this non-equilibrium state, the sound velocity increases, and the local supersonic zone with second sonic plane (second CJ plane) appears. So the new mode of detonation wave is predicted. Equations describing this mode of detonation are presented. The exact analytical solution for the second CJ plane parameters is obtained. The example of double-front detonation in high explosive (TNT) is presented. In this double-front structure "nanodiamond-nanographite" phase transition takes place in condensed particles of detonation products.

  1. Double-diffusive layer formation

    NASA Astrophysics Data System (ADS)

    Zaussinger, Florian; Kupka, Friedrich; Hücker, Sebastian; Egbers, Christoph

    2015-04-01

    Double-diffusive convection plays an important role in geo- and astrophysical applications. The special case, where a destabilising temperature gradient counteracts a stabilising solute gradient leads to layering phenomena under certain conditions. Convectively mixed layers sandwiched in diffusive interfaces form a so-called stack. Well-known double-diffusive systems are observed in rift lakes in Africa and even from the coffee drink Latte Macciatto. Stacks of layers are also predicted to occur inside massive stars and inside giant planets. Their dynamics depend on the thermal, the solute and the momentum diffusivities, as well on the ratio of the gradients of the opposing stratifications. Since the layering process cannot be derived from linear stability analysis, the full nonlinear set of equations has to be investigated. Numerical simulations have become feasible for this task, despite the physical processes operate on a vast range of length and time scales, which is challenging for numerical hydrodynamical modelling. The oceanographically relevant case of fresh and salty water is investigated here in further details. The heat and mass transfer is compared with theoretical results and experimental measurements. Additionally, the initial dynamic of layering, the transient behaviour of a stack and the long time evolution are presented using the example of Lake Kivu and the interior of a giant planet.

  2. Vesicles with a double bilayer.

    PubMed

    Zawada, Zygmunt H

    2004-01-01

    A modified reverse phase evaporation method was used to prepare intermediate unilamellar vesicles coated with an additional membrane, or large vesicles in which several vesicles were coated with a common membrane. In both kinds of vesicle, the outer and inner membranes are usually of different phospholipid composition. The preparation involves the formation of a double emulsion: vesicles in a buffer are emerged in a low-boiling point organic solution of phospholipids. Then the organic solvent is evaporated during the heating and mixing process. As result large unilamellar vesicles (LUVs), about 100 nm in diameter, were coated with an additional membrane from egg lecithin or dipalmitoylphosphatidylcholine and cholesterol. The highest yield of the coating was about 50%. When DPPC was used for coating above the phase transition temperature Tm, the data suggested the formation of vesicles that were slightly larger than the starting LUVs. It might be concluded that many of these had a double bilayer. If the coating was done below Tm, the micrographs suggested the formation of structures resembling multi-vesicular vesicles. They looked like LUV clusters coated with a common membrane.

  3. Double Exposure: Photographing Climate Change

    NASA Astrophysics Data System (ADS)

    Arnold, D. P.; Wake, C. P.; Romanow, G. B.

    2008-12-01

    Double Exposure, Photographing Climate Change, is a fine-art photography exhibition that examines climate change through the prism of melting glaciers. The photographs are twinned shots of glaciers, taken in the mid-20th century by world-renowned photographer Brad Washburn, and in the past two years by Boston journalist/photographer David Arnold. Arnold flew in Washburn's aerial "footprints", replicating stunning black and white photographs, and documenting one irreversible aspect of climate change. Double Exposure is art with a purpose. It is designed to educate, alarm and inspire its audiences. Its power lies in its beauty and the shocking changes it has captured through a camera lens. The interpretive text, guided by numerous experts in the fields of glaciology, global warming and geology, helps convey the message that climate change has already forced permanent changes on the face of our planet. The traveling exhibit premiered at Boston's Museum of Science in April and is now criss-crossing the nation. The exhibit covers changes in the 15 glaciers that have been photographed as well as related information about global warming's effect on the planet today.

  4. ATHLETE : Double Auger Anchoring Mechanism

    NASA Technical Reports Server (NTRS)

    Shin, Joseph

    2011-01-01

    The All-Terrain Hex-Legged Extra-Terrestrial Explorer (ATHLETE) is a six-limbed robot designed to support surface explorations on Near Earth Objects, the Moon and Mars. ATHLETE can carry large payloads on its top deck and can carry a fully equipped pressurized habitat in low gravity. The robot has wheels on each of its six articulated limbs, allowing it to actively conform to terrain while driving and to walk when driving is impractical. With the use of a tool adapter, ATHLETE limbs can be equipped with end effectors to support various mission objectives. For work on Near Earth Objects and other microgravity environments, an anchoring mechanism is needed to keep the ATHLETE from floating off the surface. My goal for this spring session at JPL was to design and build a counter rotating, double auger, anchoring mechanism. The mechanism mates to the tool adapter and is driven off the wheel motor. The double auger anchoring mechanism will be tested in a regolith simulant that will determine the uplift capacity of the anchoring mechanism.

  5. Infinite sets and double binds.

    PubMed

    Arden, M

    1984-01-01

    There have been many attempts to bring psychoanalytical theory up to date. This paper approaches the problem by discussing the work of Gregory Bateson and Ignacio Matte-Blanco, with particular reference to the use made by these authors of Russell's theory of logical types. Bateson's theory of the double bind and Matte-Blanco's bilogic are both based on concepts of logical typing. It is argued that the two theories can be linked by the idea that neurotic symptoms are based on category errors in thinking. Clinical material is presented from the analysis of a middle-aged woman. The intention is to demonstrate that the process of making interpretations can be thought of as revealing errors in thinking. Changes in the patient's inner world are then seen to be the result of clarifying childhood experiences based on category errors. Matte-Blanco's theory of bilogic and infinite experiences is a re-evaluation of the place of the primary process in mental life. It is suggested that a combination of bilogic and double bind theory provides a possibility of reformulating psychoanalytical theory.

  6. Double Standards in Global Health

    PubMed Central

    Admay, Catherine; Shakow, Aaron; Keshavjee, Salmaan

    2016-01-01

    Abstract The human rights arguments that underpinned the fight against HIV over the last three decades were poised, but ultimately failed, to provide a similar foundation for success against multidrug-resistant TB (MDR-TB) and other diseases of the poor. With more than 1.5 million deaths since 2000 attributed to strains of MDR-TB, and with half a million new, and mostly untreated, MDR-TB cases in the world each year, the stakes could not be higher. The World Health Organization (WHO), whose mandate is to champion the attainment by all peoples of the highest possible level of health, recommended unsound medical treatment for MDR-TB patients in resource-poor settings from 1993-2002. Citing cost considerations, WHO did not recommend the available standard of care that had been successfully used to contain and defeat MDR-TB in rich countries. By acting as a strategic gatekeeper in its technical advisory role to donor agencies and countries, it also facilitated the global implementation of a double standard for TB care in low- and middle-income countries (LMICs), upending important legal and scientific priorities. This raises serious questions about whether the organization violated international human rights standards and those established in its own constitution. While calling for additional analysis and discussion on this topic, the authors propose that policymakers should reject double standards of this kind and instead embrace the challenge of implementing the highest standard of care on a global level. PMID:27781001

  7. Double Photoionization of Atomic Beryllium

    NASA Astrophysics Data System (ADS)

    Yip, Frank L.; McCurdy, C. William; Rescigno, Thomas N.

    2010-03-01

    One-photon double ionization (DPI) of beryllium represents the next step in the evolution of DPI investigations that began with helium in order to sensitively probe electron correlation. Beryllium is the simplest atomic species of the alkaline earth elements which, in general, possess two electrons outside of a fully occupied inner shell that spherically screens the nucleus. This provides a natural basis for comparison to 1s^2 helium DPI. However, the valence state of beryllium has n=2, thus making the valence excited target 2s2p more accessible relative to the 2s^2 ground state as compared to ground-state and metastable helium. Also, the symmetry of photoionizing from either the ^1S or ^1P initial state will have consequences for the angular distributions for double ionization. Triply differential cross sections (TDCS) are presented for DPI from both ground state 2s^2 and excited state 2s2p beryllium calculated using exterior complex scaling (ECS) for the valence electrons.

  8. Gender Double Standards in Parenting Attitudes*

    PubMed Central

    Axinn, William G.; Young-DeMarco, Linda; Ro, Meeso Caponi

    2010-01-01

    This paper investigates the double standard in attitudes toward courtship and family formation behaviors of sons and daughters. We argue there are strong theoretical reasons to expect that the magnitude of this double standard varies across substantive domains, as well as amongst parents and non-parents. We also argue key methodological limitations of previous studies likely produce an under-estimate of the gender double standard. We provide empirical estimates of the gender double standard that overcome these limitations, including a random assignment experiment explicitly designed to control the effects of social desirability. These estimates demonstrate variability in the double standard across domains and reveal key factors contributing to the magnitude of the double standards in parenting attitudes held by individuals. PMID:21318125

  9. Double-Swivel Mechanism For Reliable Release

    NASA Technical Reports Server (NTRS)

    King, Guy L.; Schneider, William C.

    1990-01-01

    Double-swivel toggle mechanism releases large, heavy objects reliably. Double-swiveling action of mechanism ensures it clears restraining pins upon release. Pins retain toggle and its load. If pin fails to withdraw at designated time for releasing payload, toggle swivels about its upper ball, and ring swivels about lower ball so ring flange clears failed pin. Double-swivel action ensures disengagement even it two pins fail to withdraw.

  10. Constitutive Parameter Measurement Using Double Ridge Waveguide

    DTIC Science & Technology

    2013-03-01

    CONSTITUTIVE PARAMETER MEASUREMENT USING DOUBLE RIDGE WAVEGUIDE THESIS Nathan J. Lehman, Captain, USAF AFIT-ENG-13-M-30 DEPARTMENT OF THE AIR FORCE...copyright protection in the United States. AFIT-ENG-13-M-30 CONSTITUTIVE PARAMETER MEASUREMENT USING DOUBLE RIDGE WAVEGUIDE THESIS Presented to the Faculty...PARAMETER MEASUREMENT USING DOUBLE RIDGE WAVEGUIDE Nathan J. Lehman, B.S.E.E. Captain, USAF Approved: Michael Havrilla, PhD (Chairman) Maj Milo Hyde, PhD

  11. Controlled double-slit electron diffraction

    NASA Astrophysics Data System (ADS)

    Bach, Roger; Pope, Damian; Liou, Sy-Hwang; Batelaan, Herman

    2013-03-01

    Double-slit diffraction is a corner stone of quantum mechanics. It illustrates key features of quantum mechanics: interference and the particle-wave duality of matter. In 1965, Richard Feynman presented a thought experiment to show these features. Here we demonstrate the full realization of his famous thought experiment. By placing a movable mask in front of a double-slit to control the transmission through the individual slits, probability distributions for single- and double-slit arrangements were observed. Also, by recording single electron detection events diffracting through a double-slit, a diffraction pattern was built up from individual events.

  12. William Doberck - double star astronomer

    NASA Astrophysics Data System (ADS)

    MacKeown, P. Kevin

    2007-03-01

    We outline the role of astronomy in the career of William Doberck (1852-1941). After taking a PhD in astronomy at the University of Jena in 1873, he accepted a position as superintendent of Markree Observatory in the west of Ireland. There he refurbished the great 13-inch refractor and spent nine years observing mostly double star systems, paying only such attention to meteorological monitoring as was required of his position. In 1883 he became the founding Director of a new observatory in Hong Kong, a post which he held for 24 years. His frustrations in attempting to continue his purely astronomical work, not assuaged by his combative and prickly personality, and in the face of the strictly practical demands of that mercantile society for comprehensive storm forecasting, are described. Finally, his observations in retirement in England, and his overall contribution to astronomy, are summarised.

  13. Double photoionization of halogenated benzene

    SciTech Connect

    AlKhaldi, Mashaal Q.; Wehlitz, Ralf

    2016-01-28

    We have experimentally investigated the double-photoionization process in C{sub 6}BrF{sub 5} using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C{sub 6}H{sub 3}D{sub 3}) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance.

  14. Doubling bialgebras of rooted trees

    NASA Astrophysics Data System (ADS)

    Mohamed, Mohamed Belhaj; Manchon, Dominique

    2017-01-01

    The vector space spanned by rooted forests admits two graded bialgebra structures. The first is defined by Connes and Kreimer using admissible cuts, and the second is defined by Calaque, Ebrahimi-Fard and the second author using contraction of trees. In this article, we define the doubling of these two spaces. We construct two bialgebra structures on these spaces which are in interaction, as well as two related associative products obtained by dualization. We also show that these two bialgebras verify a commutative diagram similar to the diagram verified Calaque, Ebrahimi-Fard and the second author in the case of rooted trees Hopf algebra, and by the second author in the case of cycle-free oriented graphs.

  15. Double Compton scatter telescope calibration

    NASA Technical Reports Server (NTRS)

    Dayton, B.; Simone, J.; Green, M.; Long, J.; Zanrosso, E.; Zych, A. D.; White, R. S.

    1981-01-01

    Calibration techniques for a medium energy gamma ray telescope are described. Gain calibration using Compton edge spectra involves comparisons of pulse height spectra with spectra simulated by a Monte Carlo computer code which includes Compton scattering and pair production, plural scattering and variable energy resolution, and cell size. The telescope considered comprises 56 cells of liquid scintillator in four size groups, with a total liquid volume of 325 l; each cell has its own photomultiplier tube. Energy and angular resolutions and the PMT gain calibration procedure are verified with double scatter data for monoenergetic gamma rays at a known location. Detection probabilities for any cell combination in the two telescope arrays are calculated per steradian as a function of the scattering for a number of different energies with a Van de Graaff accelerator.

  16. Double-crop sunflowers for agricultural diesel fuel

    SciTech Connect

    Glenn, T.L.; Keener, H.M.; Henry, J.E.; Triplett, G.B. Jr.

    1982-01-01

    Agronomic and engineering information on double-crop sunflower production, processing and utilization is presented. This and other available information is used to assess feasibility and future directions in the use of sunflower oil for agricultural diesel fuel in the US Eastern Corn Belt area. Double-cropping yields varied considerably due to precipitation extremes, plus different soil characteristics and management practices. Average expeller oil yields of 0.344 kg of oil per kg of moisture free seed were achieved with a feed rate of 125 kg per hour for a range in seed and processing conditions. Results from feasibility analyses suggest that sunflower oil can be grown in Ohio and processed in a community cooperative plant with a favorable energy ratio and marginal profitability. 3 figures, 4 tables.

  17. An interesting prenatal diagnosis: double aneuploidy.

    PubMed

    Aydin, Cetin; Eris, Serenat; Yalcin, Yakup; Sen Selim, Halime

    2013-01-01

    Double aneuploidy, the existence of two chromosomal abnormalities in the same individual, is a rare condition. Early diagnosis of this condition is important to offer termination of pregnancy in genetic counselling. Cytogenetic analysis with amniocentesis and ultrasound examination is valuable for diagnosis of double aneuploidy. In this report we present a case with the karyotype of 48XXY+21 diagnosed prenatally.

  18. Double Prosecution of the State University Student

    ERIC Educational Resources Information Center

    Kelly, Thomas E., Jr.

    1974-01-01

    Explores whether the state university student confronted with double prosecution (university disciplinary proceedings and state or municipal criminal proceedings) has any constitutional basis for claiming the applicability of double jeopardy protection of the Fifth Amendment as a bar to a second prosecution. Concludes that the issue is not…

  19. The Sexual Double Standard: How Prevalent Today?

    ERIC Educational Resources Information Center

    Sack, Alan R.; And Others

    1981-01-01

    Studied the sexual double standard among university students. Females showed a stronger association between premarital intercourse and affection and perceived less approval from five reference groups for their sexual behavior than did males. Results indicate the sexual double standard is still evident among the present group of college students.…

  20. Intrateam Communication and Performance in Doubles Tennis

    ERIC Educational Resources Information Center

    Lausic, Domagoj; Tennebaum, Gershon; Eccles, David; Jeong, Allan; Johnson, Tristan

    2009-01-01

    Verbal and nonverbal communication is a critical mediator of performance in team sports and yet there is little extant research in sports that involves direct measures of communication. Our study explored communication within NCAA Division I female tennis doubles teams. Video and audio recordings of players during doubles tennis matches captured…

  1. Electric fields and double layers in plasmas

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra; Thiemann, H.; Schunk, R. W.

    1987-01-01

    Various mechanisms for driving double layers in plasmas are briefly described, including applied potential drops, currents, contact potentials, and plasma expansions. Some dynamical features of the double layers are discussed. These features, as seen in simulations, laboratory experiments, and theory, indicate that double layers and the currents through them undergo slow oscillations which are determined by the ion transit time across an effective length of the system in which double layers form. It is shown that a localized potential dip forms at the low potential end of a double layer, which interrupts the electron current through it according to the Langmuir criterion, whenever the ion flux into the double is disrupted. The generation of electric fields perpendicular to the ambient magnetic field by contact potentials is also discussed. Two different situations were considered; in one, a low-density hot plasma is sandwiched between high-density cold plasmas, while in the other a high-density current sheet permeates a low-density background plasma. Perpendicular electric fields develop near the contact surfaces. In the case of the current sheet, the creation of parallel electric fields and the formation of double layers are also discussed when the current sheet thickness is varied. Finally, the generation of electric fields and double layers in an expanding plasma is discussed.

  2. Electric fields and double layers in plasmas

    NASA Astrophysics Data System (ADS)

    Singh, Nagendra; Thiemann, H.; Schunk, R. W.

    1987-05-01

    Various mechanisms for driving double layers in plasmas are briefly described, including applied potential drops, currents, contact potentials, and plasma expansions. Some dynamical features of the double layers are discussed. These features, as seen in simulations, laboratory experiments, and theory, indicate that double layers and the currents through them undergo slow oscillations which are determined by the ion transit time across an effective length of the system in which double layers form. It is shown that a localized potential dip forms at the low potential end of a double layer, which interrupts the electron current through it according to the Langmuir criterion, whenever the ion flux into the double is disrupted. The generation of electric fields perpendicular to the ambient magnetic field by contact potentials is also discussed. Two different situations were considered; in one, a low-density hot plasma is sandwiched between high-density cold plasmas, while in the other a high-density current sheet permeates a low-density background plasma. Perpendicular electric fields develop near the contact surfaces. In the case of the current sheet, the creation of parallel electric fields and the formation of double layers are also discussed when the current sheet thickness is varied. Finally, the generation of electric fields and double layers in an expanding plasma is discussed.

  3. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, W.C.

    1988-10-11

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached. 8 figs.

  4. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, William C.

    1988-01-01

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached.

  5. Islets of stability beyond period doubling

    SciTech Connect

    Mackay, R.S.

    1981-11-01

    Period doubling of a periodic orbit of an area preserving map appears to lead to the elimination of all closed invariant curves in the vicinity. We show, however, that there are always islets of stabilhty again beyond the accumulation point of the period doubling sequence.

  6. The Doubling Moment: Resurrecting Edgar Allan Poe

    ERIC Educational Resources Information Center

    Minnick, J. Bradley; Mergil, Fernando

    2008-01-01

    This article expands upon Jeffrey Wilhelm's and Brian Edmiston's (1998) concept of a doubling of viewpoints by encouraging middle level students to use dramatization to take on multiple perspectives, to pose interpretive questions, and to enhance critical inquiry from inside and outside of texts. The doubling moment is both the activation of…

  7. Mapping the double-slit diffraction pattern

    NASA Astrophysics Data System (ADS)

    Selvaggi, Richard; Rogers, Charles; Richardson, Clay

    2010-10-01

    A red laser, movable double-slit, movable micrometer mounted single-slit light block, and CCD were utilized to map out the single and double-slit diffraction patterns between 0 and 30 millimeters. The three dimensional mapping results demonstrate that the double-slit troughs similarly redirect the electromagnetic energy and light particles. The measured alternating path of the electromagnetic energy and light particles in the double-slit diffraction pattern is different than the theoretic path of light waves defined by destructive interference and indicates that theoretical light waves do not always have electromagnetic energy. George Monk's 1937 and Richard Feynman's 1964 finding of conservation of electromagnetic energy in the double-slit light experiment present the following questions: 1) What are the mass-less and energy-less destructive interference light waves found in the double-slit troughs? 2) What force is applied to and what energy is consumed by the work of redistributing the electromagnetic energy and light particles in the double-slit diffraction pattern? 3) Is this unknown force and unknown energy the result of dark matter found in the double-slit troughs?

  8. Perspective: Double Jeopardy--Another Look.

    ERIC Educational Resources Information Center

    Bolduan, Linda M.; Dailey, Dianne K.

    1997-01-01

    Explores how a defendant can face a civil action and criminal prosecution for the same act without violating the principle of double jeopardy. For instance, burning down a house can engender criminal prosecution charges and a civil suit from the insurance company. Double jeopardy only applies to criminal actions. (MJP)

  9. Electron temperature differences and double layers

    NASA Technical Reports Server (NTRS)

    Chan, C.; Hershkowitz, N.; Lonngren, K. E.

    1983-01-01

    Electron temperature differences across plasma double layers are studied experimentally. It is shown that the temperature differences across a double layer can be varied and are not a result of thermalization of the bump-on-tail distribution. The implications of these results for electron thermal energy transport in laser-pellet and tandem-mirror experiments are also discussed.

  10. Double layers and circuits in astrophysics

    NASA Technical Reports Server (NTRS)

    Alfven, Hannes

    1986-01-01

    A simple circuit is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the Sun's axis which may give radiations detectable from earth. Double layers in space should be classified as a new type of celestial object. It is suggested that X-ray and gamma-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). The way the most used textbooks in astrophysics treat concepts like double layers, critical velocity, pinch effects and circuits was studied. It is found that students using these textbooks remain essentially ignorant of even the existence of these, although some of the phenomena were discovered 50 yr ago.

  11. Reliability Estimation for Double Containment Piping

    SciTech Connect

    L. Cadwallader; T. Pinna

    2012-08-01

    Double walled or double containment piping is considered for use in the ITER international project and other next-generation fusion device designs to provide an extra barrier for tritium gas and other radioactive materials. The extra barrier improves confinement of these materials and enhances safety of the facility. This paper describes some of the design challenges in designing double containment piping systems. There is also a brief review of a few operating experiences of double walled piping used with hazardous chemicals in different industries. This paper recommends approaches for the reliability analyst to use to quantify leakage from a double containment piping system in conceptual and more advanced designs. The paper also cites quantitative data that can be used to support such reliability analyses.

  12. Double layers and circuits in astrophysics

    NASA Technical Reports Server (NTRS)

    Alfven, H.

    1986-01-01

    A simple circuit is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the Sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object. It is suggested that X-ray and gamma-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). The way the most used textbooks in astrophysics treat concepts like double layers, critical velocity, pinch effects and circuits was studied. It is found that students using these textbooks remain essentially ignorant of even the existence of these, although some of the phenomena were discovered 50 yr ago.

  13. Reliability and validity of a new double poling ergometer for cross-country skiers.

    PubMed

    Holmberg, Hans-Christer; Nilsson, Johnny

    2008-01-15

    Thirty-eight competitive cross-country skiers were divided into three groups to assess the reliability and validity of a new double poling ergometer. Group A (n = 22) performed two maximal 60-s tests, Group B (n = 8) repeated peak oxygen uptake tests on the double poling ergometer, and Group C (n = 8) performed a maximal 6-min test on the double poling ergometer and a double poling time-trial on snow. The correlation between the power calculated at the flywheel and the power applied at the base of the poles was r = 0.99 (P < 0.05). The power at the poles was 50-70% higher than that at the flywheel. There was a high test-retest reliability in the two 60-s power output tests (coefficient of variation = 3.0%) and no significant difference in peak oxygen uptake in the two 6-min all-out tests (coefficient of variation = 2.4%). There was a strong correlation between the absolute (W) and relative power (W x kg(-1)) output in the 6-min double poling ergometer test and the double poling performance on snow (r = 0.86 and 0.89 respectively; both P < 0.05). In conclusion, our results show that the double poling ergometer has both high reliability and validity. However, the power calculated at the flywheel underestimated the total power produced and needs to be corrected for in ergonomic estimations.

  14. Double-disc gate valve

    DOEpatents

    Wheatley, Seth J.

    1979-01-01

    This invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewtih, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separtion of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve.

  15. Experimental and clinical experiences with double-velour woven Dacron prostheses.

    PubMed

    Haverich, A; Maatz, W; Stegmann, T; Oelert, H; Borst, H G

    1986-02-01

    Double-velour woven Dacron prostheses were investigated both experimentally and clinically. In 6 mongrel dogs, a tandem conduit between the right ventricle and the pulmonary artery was implanted, consisting of a plain woven and a double-velour woven graft. Following explanation after 2, 4, and 6 months, superior healing properties of the double-velour woven prostheses could be assessed by microscopy, as represented by an increase of tissue ingrowth, as well as by a thin and densely adherent inner healing capsule. Double-velour woven grafts were implanted in 50 patients undergoing open heart surgery. All grafts were presealed with fibrin glue and no bleeding could be detected at the time of implantation, even under the adverse influence of full heparinization and extracorporeal circulation.

  16. Application of double-layered skin phantoms for optical flow imaging during laser tattoo treatments

    NASA Astrophysics Data System (ADS)

    Lee, Byeong-il; Song, Woosub; Kim, Hyejin; Kang, Hyun Wook

    2016-05-01

    The feasible application of double-layered skin phantoms was evaluated to identify artificial blood flow with a Doppler optical coherence tomography (DOCT) system for laser tattoo treatments. Polydimethylsiloxane (PDMS) was used to fabricate the artificial phantoms with flow channels embedded. A double-integrating sphere system with an inverse adding-doubling method quantified both the absorption and the reduced scattering coefficients for epidermis and dermis phantoms. Both OCT and caliper measurements confirmed the double-layered phantom structure (epidermis = 136 ± 17 µm vs. dermis = 3.0 ± 0.1 mm). The DOCT method demonstrated that high flow rates were associated with high image contrast, visualizing the position and the shape of the flow channel. Application of the channel-embedded skin phantoms in conjunction with DOCT can be a reliable technique to assess dynamic variations in the blood flow during and after laser tattoo treatments.

  17. The double-dark portal

    NASA Astrophysics Data System (ADS)

    Curtin, David; Tsai, Yuhsin

    2014-11-01

    In most models of the dark sector, dark matter is charged under some new symmetry to make it stable. We explore the possibility that not just dark matter, but also the force carrier connecting it to the visible sector is charged under this symmetry. This dark mediator then acts as a Double-Dark Portal. We realize this setup in the dark mediator Dark matter model (dmDM), featuring a fermionic DM candidate χ with Yukawa couplings to light scalars ϕ i . The scalars couple to SM quarks via the operator . This can lead to large direct detection signals via the 2 → 3 process χ N → χ N ϕ if one of the scalars has mass ≲ 10 keV. For dark matter Yukawa couplings y χ ˜ 10-3 -10-2, dmDM features a thermal relic dark matter candidate while also implementing the SIDM scenario for ameliorating inconsistencies between dwarf galaxy simulations and observations. We undertake the first systematic survey of constraints on light scalars coupled to the SM via the above operator. The strongest constraints are derived from a detailed examination of the light mediator's effects on stellar astrophysics. LHC experiments and cosmological considerations also yield important bounds. Observations of neutron star cooling exclude the minimal model with one dark mediator, but a scenario with two dark mediators remains viable and can give strong direct detection signals. We explore the direct detection consequences of this scenario and find that a heavy dmDM candidate fakes different WIMPs at different experiments. Large regions of dmDM parameter space are accessible above the irreducible neutrino background.

  18. Double-reed exhaust valve engine

    DOEpatents

    Bennett, Charles L.

    2015-06-30

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a double reed outlet valve for controlling the flow of low-pressure working fluid out of the engine. The double reed provides a stronger force resisting closure of the outlet valve than the force tending to open the outlet valve. The double reed valve enables engine operation at relatively higher torque and lower efficiency at low speed, with lower torque, but higher efficiency at high speed.

  19. Vacuum leak detection for double bottom tanks

    SciTech Connect

    Hagen, T.; Rials, R.

    1995-12-31

    Double bottom tanks offer strong leak detection advantages. By incorporating the use of vacuum detection between the two bottoms, the tank bottoms can be verified leak free after construction and during tank use. Utilizing vacuum leak detection requires special considerations. In 1992 a tank construction company built 10 tanks for an oil company in Ponca City, Oklahoma. Each of these tanks were built with a double bottom. This paper provides insight into the planning, construction and testing of this type of double bottom design.

  20. Earthquakes with non--double-couple mechanisms.

    PubMed

    Frohlich, C

    1994-05-06

    Seismological observations confirm that the pattern of seismic waves from some earthquakes cannot be produced by slip along a planar fault surface. More than one physical mechanism is required to explain the observed varieties of these non-double-couple earthquakes. The simplest explanation is that some earthquakes are complex, with stress released on two or more suitably oriented, nonparallel fault surfaces. However, some shallow earthquakes in volcanic and geothermal areas require other explanations. Current research focuses on whether fault complexity explains most observed non-double-couple earthquakes and to what extent ordinary earthquakes have non-double-couple components.

  1. Medication double-checking procedures in clinical practice: a cross-sectional survey of oncology nurses' experiences

    PubMed Central

    Pfeiffer, Yvonne; Taxis, Katja

    2016-01-01

    Background Double-checking is widely recommended as an essential method to prevent medication errors. However, prior research has shown that the concept of double-checking is not clearly defined, and that little is known about actual practice in oncology, for example, what kind of checking procedures are applied. Objective To study the practice of different double-checking procedures in chemotherapy administration and to explore nurses' experiences, for example, how often they actually find errors using a certain procedure. General evaluations regarding double-checking, for example, frequency of interruptions during and caused by a check, or what is regarded as its essential feature was assessed. Methods In a cross-sectional survey, qualified nurses working in oncology departments of 3 hospitals were asked to rate 5 different scenarios of double-checking procedures regarding dimensions such as frequency of use in practice and appropriateness to prevent medication errors; they were also asked general questions about double-checking. Results Overall, 274 nurses (70% response rate) participated in the survey. The procedure of jointly double-checking (read-read back) was most commonly used (69% of respondents) and rated as very appropriate to prevent medication errors. Jointly checking medication was seen as the essential characteristic of double-checking—more frequently than ‘carrying out checks independently’ (54% vs 24%). Most nurses (78%) found the frequency of double-checking in their department appropriate. Being interrupted in one's own current activity for supporting a double-check was reported to occur frequently. Regression analysis revealed a strong preference towards checks that are currently implemented at the responders' workplace. Conclusions Double-checking is well regarded by oncology nurses as a procedure to help prevent errors, with jointly checking being used most frequently. Our results show that the notion of independent checking needs to be

  2. Self-reported effectiveness of double-fine zones as a speed control measure.

    PubMed

    Jones, Barnie; Haas, Kevin; Kirk, Alan; Griffith, Andrew

    2004-01-01

    This study evaluated the effectiveness of signs alerting drivers to double traffic fines in highway work zones, school zones and safety corridors. The evaluation was based on a driver survey that investigated the decision to exceed speed limits across a range of driving contexts and risk categories. The findings indicated that personal assessments of risk change from one hypothetical situation to another, suggesting that people make a more or less calculated decision to violate the speed limit, based on those risks. The findings also suggested that people perceive a higher relative risk associated with traffic fines if the situation is one in which a doubling of traffic fines may apply. Finally, the results showed that interview subjects who reported being aware of double-fine zones tended to have somewhat higher assessments of the risk associated with traffic citations, traffic fines and higher insurance rates.

  3. A new hydrodynamic analysis of double layers

    NASA Technical Reports Server (NTRS)

    Hora, Heinrich

    1987-01-01

    A genuine two-fluid model of plasmas with collisions permits the calculation of dynamic (not necessarily static) electric fields and double layers inside of plasmas including oscillations and damping. For the first time a macroscopic model for coupling of electromagnetic and Langmuir waves was achieved with realistic damping. Starting points were laser-produced plasmas showing very high dynamic electric fields in nonlinear force-produced cavitous and inverted double layers in agreement with experiments. Applications for any inhomogeneous plasma as in laboratory or in astrophysical plasmas can then be followed up by a transparent hydrodynamic description. Results are the rotation of plasmas in magnetic fields and a new second harmonic resonance, explanation of the measured inverted double layers, explanation of the observed density-independent, second harmonics emission from laser-produced plasmas, and a laser acceleration scheme by the very high fields of the double layers.

  4. Inverse solutions for tilting orthogonal double prisms.

    PubMed

    Li, Anhu; Ding, Ye; Bian, Yongming; Liu, Liren

    2014-06-10

    An analytical reverse solution and actual examples are given to show how to direct a laser beam from a pair of orthogonal prisms to given targets in free space. Considering the influences of double-prism structural parameters, a lookup table method to seek the numerical reverse solution of each prism's tilting angle is also proposed for steering the double-prism orientation to track a target position located in the near field. Some case studies, as well as a specified elliptical target trajectory scanned by the cam-based driving double prisms, exhibit the significant application values of the theoretical derivation. The analytic reverse and numerical solutions can be generalized to investigate the synthesis of scanning patterns and the controlling strategy of double-prism tilting motion, the potentials of which can be explored to perform the orientation and position tracking functions in applications of precision engineering fields.

  5. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Rob; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This slide presentation reviews the power frequencies for the doubled fiber laser. It includes information on the 780 nm laser, second harmonic generation in one crystal, cascading crystals, the tenability of laser systems, laser cooling, and directions for future work.

  6. Improved double beam, vacuum far infrared spectrophotometer.

    PubMed

    Iwahashi, I; Matsumoto, K; Matsudaira, S; Minami, S; Yoshinaga, H

    1969-03-01

    A double beam far ir spectrophotometer was improved in order to give more convenience and higher performance. The instrument is evacuable and the sample chamber alone can also be purged with dry air to remove water vapor. Three photometric systems, i.e., conventional double beam, double beam double chopping, and single beam systems can be selected for versatile measurements. The use of an efficient transmission filter system, not involving deliquescent crystals, results in many operational advantages. Accordingly, high resolution can be obtained through the entire spectral region from 400 cm(-1) to 30 cm(-1) Moreover, 30-min scan over the entire spectral region is achieved by completely automatic operation with a refined control system.

  7. Frequency Doubling Broadband Light in Multiple Crystals

    SciTech Connect

    ALFORD,WILLIAM J.; SMITH,ARLEE V.

    2000-07-26

    The authors compare frequency doubling of broadband light in a single nonlinear crystal with doubling in five crystals with intercrystal temporal walk off compensation, and with doubling in five crystals adjusted for offset phase matching frequencies. Using a plane-wave, dispersive numerical model of frequency doubling they study the bandwidth of the second harmonic and the conversion efficiency as functions of crystal length and fundamental irradiance. For low irradiance the offset phase matching arrangement has lower efficiency than a single crystal of the same total length but gives a broader second harmonic bandwidth. The walk off compensated arrangement gives both higher conversion efficiency and broader bandwidth than a single crystal. At high irradiance, both multicrystal arrangements improve on the single crystal efficiency while maintaining broad bandwidth.

  8. Nonlinear dynamics of a double bilipid membrane.

    PubMed

    Sample, C; Golovin, A A

    2007-09-01

    The nonlinear dynamics of a biological double membrane that consists of two coupled lipid bilayers, typical of some intracellular organelles such as mitochondria or nuclei, is studied. A phenomenological free-energy functional is formulated in which the curvatures of the two parts of the double membrane and the distance between them are coupled to the lipid chemical composition. The derived nonlinear evolution equations for the double-membrane dynamics are studied analytically and numerically. A linear stability analysis is performed, and the domains of parameters are found in which the double membrane is stable. For the parameter values corresponding to an unstable membrane, numerical simulations are performed that reveal various types of complex dynamics, including the formation of stationary, spatially periodic patterns.

  9. Double Power: English Literacy and Indigenous Education.

    ERIC Educational Resources Information Center

    Wignell, Peter, Ed.

    The collection of essays on the relationship between English literacy and indigenous education, particularly in the Australian context, includes: "Double Power" (Mandawuy Yunupingu); "History, Cultural Diversity & English Language Teaching" (Martin Nakata); "Scaffolding Reading and Writing for Indigenous Children in…

  10. Dry Eyes and Glaucoma: Double Trouble

    MedlinePlus

    ... News About Us Donate In This Section Dry Eyes and Glaucoma: Double Trouble email Send this article ... disease bothers the patient more. What Causes Dry Eye Syndrome? Dry eye can be caused by many ...

  11. Over-under double-pass interferometer

    NASA Technical Reports Server (NTRS)

    Schindler, R. A. (Inventor)

    1977-01-01

    An over-under double pass interferometer in which the beamsplitter area and thickness can be reduced to conform only with optical flatness considerations was achieved by offsetting the optical center line of one cat's-eye retroreflector relative to the optical center line of the other in order that one split beam be folded into a plane distinct from the other folded split beam. The beamsplitter is made transparent in one area for a first folded beam to be passed to a mirror for doubling back and is made totally reflective in another area for the second folded beam to be reflected to a mirror for doubling back. The two beams thus doubled back are combined in the central, beamsplitting area of the beamsplitting and passed to a detector. This makes the beamsplitter insensitive to minimum thickness requirements and selection of material.

  12. Review of modern double beta decay experiments

    SciTech Connect

    Barabash, A. S.

    2015-10-28

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T{sub 1/2}(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino (〈m{sub ν}〉 < 0.46 eV) and a coupling constant of Majoron to neutrino (〈g{sub ee}〉 < 1.3 · 10{sup −5}) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to 〈m{sub ν}〉 at the level of ∼ 0.01-0.1 eV are discussed.

  13. Double Shell Tank (DST) Transfer Valving Specification

    SciTech Connect

    GRAVES, C.E.

    2001-01-17

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Transfer Valving Subsystem that supports the first phase of Waste Feed Delivery.

  14. The Double Scene of Televised AIDS Campaigns.

    ERIC Educational Resources Information Center

    Cummings, Kate

    1992-01-01

    Analyzes the double or mirrored scene of the Centers for Disease Control's AIDS education campaign and the responses to that campaign, basically, the dominant, heterosexual, televised discourses' defensive erasure of those semiotic objects that represent illicit and nonreproductive sex. (RS)

  15. Don't Double Up on Acetaminophen

    MedlinePlus

    ... Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Don't Double ... products. January 24, 2013 back to top Related Consumer Updates Have a Baby or Young Child With ...

  16. Crack Propagation in Double-Base Propellants

    DTIC Science & Technology

    1976-01-01

    propagation tests were conducted on a composite modified double- base ( CMDB ) propellant with the use of center-cracked strip biaxial specimens...double-base ( CMDB ) propellant. He performed a stress analysis of small, precracked, subscale STV motors formulated in terms of stress intensity factors...assumed for Solithane 113. The present program was aimed at evaluating the Schapery theory when it was applied to a CMDB propellant under similar loading

  17. Double-Diffusive Convection in Rotational Shear

    DTIC Science & Technology

    2015-03-01

    CONVECTION IN ROTATIONAL SHEAR by James S. Ball March 2015 Thesis Advisor: Timour Radko Second Reader: John Colosi THIS PAGE...AND SUBTITLE 5. FUNDING NUMBERS DOUBLE-DIFFUSIVE CONVECTION IN ROTATIONAL SHEAR 6. AUTHOR(S) James S. Ball 7. PERFORMING ORGANIZATION NAME(S) AND...INTENTIONALLY LEFT BLANK ii Approved for public release;distribution is unlimited DOUBLE-DIFFUSIVE CONVECTION IN ROTATIONAL SHEAR James S. Ball

  18. Robotic-assisted double-sleeve lobectomy

    PubMed Central

    Qiu, Tong; Zhao, Yandong; Xuan, Yunpeng

    2017-01-01

    Double-sleeve lobectomy, which includes bronchoplasty and pulmonary arterial angioplasty, is required for certain cases of central-type lung cancer. It is usually done by open surgery or video-assisted thoracoscopic surgery (VATS). In recently, da Vinci system and robotic surgery have been applied in such complicated cases. Here we describe the details associated with robotic-assisted double-sleeve lobectomy. PMID:28203433

  19. Decay properties of double heavy baryons

    SciTech Connect

    Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery; Ivanov, Mikhail A.; Koerner, Juergen G.

    2010-08-05

    We study the semileptonic decays of double heavy baryons using a manifestly Lorentz covariant constituent three-quark model. We present complete results on transition form factors between double-heavy baryons for finite values of the heavy quark/baryon masses and in the heavy quark symmetry limit which is valid at and close to zero recoil. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit.

  20. [Veterinary double-monsters historically viewed].

    PubMed

    Baljet, B; Heijke, G C

    1997-01-01

    A large number of duplication monstrosities have been observed in cattle, sheep, pigs, horses, goats, cats and dogs, ever since the publication of the famous woodcut of a swine double monster by J. S. Brant in Basel in 1496, better known as the "wunderbare Sau von Landser im Elsass". Albrecht Dürer also made a woodcut of this double monster in front of the village Landser in 1496. A picture of a deer double monster was published in 1603 by Heinrich Ulrich in Germany. In the monograph De monstrorum causis, natura et differentiis ..., published by the Italian Fortunius Licetus in 1616 pictures of double monsters being half man half dog are found. These fantasy figures have been popular for a long time and were supposed to be really in existence. Apart from these fantasy figures many pictures are known from real veterinary double monsters. U. Aldrovandus described in 1642 in his Monstrorum historia, besides many fantasy figures, also real human and veterinary double monsters and he gave also good pictures of them. In the 19th century examples of veterinary duplication monstrosities were published by I. Geoffroy Saint-Hilaire (1832-37), E. F. Gurlt (1832), W. Vrolik (1840) and C. Taruffi (1881); they proposed also concepts concerning the etiology. In the second volume of his famous handbook of teratology (1907), E. Schwalbe described many veterinary double monsters and discussed the theories of the genesis of congenital malformations. Various theories concerning the genesis of double monsters have been given since Aristotle (384-322 B.C.). ...

  1. Wavelength-doubling optical parametric oscillator

    DOEpatents

    Armstrong, Darrell J.; Smith, Arlee V.

    2007-07-24

    A wavelength-doubling optical parametric oscillator (OPO) comprising a type II nonlinear optical medium for generating a pair of degenerate waves at twice a pump wavelength and a plurality of mirrors for rotating the polarization of one wave by 90 degrees to produce a wavelength-doubled beam with an increased output energy by coupling both of the degenerate waves out of the OPO cavity through the same output coupler following polarization rotation of one of the degenerate waves.

  2. The HIPPARCOS Double and Multiple Star Solutions

    NASA Astrophysics Data System (ADS)

    Mignard, F.

    The Hipparcos catalogue provides general astrometric and photometric information on double and multiple stars in specific fields of the main catalogue and detailed data on the components in the various sections of a dedicated annex: the Double and Multiple Systems Annex (DMSA). Overall statistics of these solutions are presented for the 13,211 entries of this annex and the different types of solutions are outlined.

  3. Double shell tank waste analysis plan

    SciTech Connect

    Mulkey, C.H.; Jones, J.M.

    1994-12-15

    Waste analysis plan for the double shell tanks. SD-WM-EV-053 is Superseding SD-WM-EV-057.This document provides the plan for obtaining information needed for the safe waste handling and storage of waste in the Double Shell Tank Systems. In Particular it addresses analysis necessary to manage waste according to Washington Administrative Code 173-303 and Title 40, parts 264 and 265 of the Code of Federal Regulations.

  4. Double peak sensory responses: effects of capsaicin.

    PubMed

    Aprile, I; Tonali, P; Stalberg, E; Di Stasio, E; Caliandro, P; Foschini, M; Vergili, G; Padua, L

    2007-10-01

    The aim of this study is to verify whether degeneration of skin receptors or intradermal nerve endings by topical application of capsaicin modifies the double peak response obtained by submaximal anodal stimulation. Five healthy volunteers topically applied capsaicin to the finger-tip of digit III (on the distal phalanx) four times daily for 4-5 weeks. Before and after local capsaicin applications, we studied the following electrophysiological findings: compound sensory action potential (CSAP), double peak response, sensory threshold and double peak stimulus intensity. Local capsaicin application causes disappearance or decrease of the second component of the double peak, which gradually increases after the suspension of capsaicin. Conversely, no significant differences were observed for CSAP, sensory threshold and double peak stimulus intensity. This study suggests that the second component of the double peak may be a diagnostic tool suitable to show an impairment of the extreme segments of sensory nerve fibres in distal sensory axonopathy in the early stages of damage, when receptors or skin nerve endings are impaired but undetectable by standard nerve conduction studies.

  5. Fluid dynamics of double diffusive systems

    SciTech Connect

    Koseff, J.R.

    1989-04-07

    A study of mixing processes in doubly diffusive systems is being conducted. Continuous gradients of two diffusing components (heat and salinity in our case) are being used as initial conditions, and forcing is introduced by lateral heating and surface shear. The goals of the proposed work include: (1) quantification of the effects of finite amplitude disturbances on stable, double diffusive systems, particularly with respect to lateral heating, (2) development of an improved understanding of the physical phenomena present in wind-driven shear flows in double diffusive stratified environments, (3) increasing our knowledge-base on turbulent flow in stratified environments and how to represent it, and (4) formulation of a numerical code for such flows. The work is being carried out in an experimental facility which is located in the Stanford Environmental Fluid Mechanics Laboratory, and on laboratory minicomputers and CRAY computers. In particular we are focusing on the following key issues: (1) the formation and propagation of double diffusive intrusions away from a heated wall and the effects of lateral heating on the double diffusive system; (2) the interaction between the double diffusively influenced fluxes and the turbulence induced fluxes; (3) the measurement of heat and mass fluxes; and (4) the influence of double diffusive gradients on mixed layer deepening. 1 fig.

  6. The Design and its Verification of the Double Rotor Double Cage Induction Motor

    NASA Astrophysics Data System (ADS)

    Sinha, Sumita; Deb, Nirmal K.; Biswas, Sujit K.

    2017-02-01

    The concept of a double rotor motor presented earlier and its equivalent circuit has been developed, showing a non-linear parameter content. The two rotors (which are recommended to be double cage type for development of high starting torque) can run with equal or unequal speed independently, depending on their individual loading. This paper presents the elaborate design procedure, step-by-step, for the double rotor double cage motor and verifies the designed data with that obtained from three separate tests (compared to two for conventional motor) on a prototype, such that optimum performance can be obtained from the motor.

  7. [Drug modification of double-contrast imaging of the small intestine].

    PubMed

    Weidenmaier, W; Friedrich, J M; Schif, A; Schumacher, K A

    1990-02-01

    The intravenous use of metoclopramid (paspertin) and ceruletid (Takus) reduces the time required for fractionated double contrast examinations of the small bowel. It also improves visualisation of individual sections of the small bowel, particularly the terminal ileum. The value of these drugs has been assessed in a prospective study in 48 patients with suspected Crohn's disease.

  8. Double-blind trial of thiothixene and chlorpromazine in acute schizophrenia.

    PubMed

    Rickels, K; Byrdy, H; Valentine, J; Postel, W; Norstad, N; Downing, R

    1978-01-01

    In a double-blind trial of chlorpromazine and thiothixene conducted with 79 acutely ill, newly hospitalized schizophrenic patients, chlorpromazine and thiothixene were shown to be equally effective in producing meaningful symptomatic improvment over an average period of approximately 3 weeks, as measured by Global Assessments (CGI), BPRS, and NOSIE.

  9. Ground coupling and single-blow thermal storage in a double-envelope house

    NASA Astrophysics Data System (ADS)

    Ghaffari, H. T.; Jones, R. F.

    1981-04-01

    The possibility of ground thermal storage and coupling in a double shell house was investigated. Temperature distribution in the ground, utilization of measured ground temperatures, and the amount of heat retrieval are assessed. One experimental model and several hypothetical models are introduced, and their affects and advantages are compared.

  10. RBC aggregation dynamics in autologous plasma and serum studied with double-channel optical tweezers

    NASA Astrophysics Data System (ADS)

    Lee, Kisung; Danilina, Anna; Potkin, Anton; Kinnunen, Matti; Priezzhev, Alexander; Meglinski, Igor

    2016-04-01

    Red blood cells aggregating and disaggregating forces were measured in the autologous plasma and serum using the double-channeled optical tweezers. A significant, three-fold decrease of the both forces was observed in the serum compared to the plasma. The results of this study help to better assess the RBC aggregation mechanism.

  11. Overlay metrology for double patterning processes

    NASA Astrophysics Data System (ADS)

    Leray, Philippe; Cheng, Shaunee; Laidler, David; Kandel, Daniel; Adel, Mike; Dinu, Berta; Polli, Marco; Vasconi, Mauro; Salski, Bartlomiej

    2009-03-01

    The double patterning (DPT) process is foreseen by the industry to be the main solution for the 32 nm technology node and even beyond. Meanwhile process compatibility has to be maintained and the performance of overlay metrology has to improve. To achieve this for Image Based Overlay (IBO), usually the optics of overlay tools are improved. It was also demonstrated that these requirements are achievable with a Diffraction Based Overlay (DBO) technique named SCOLTM [1]. In addition, we believe that overlay measurements with respect to a reference grid are required to achieve the required overlay control [2]. This induces at least a three-fold increase in the number of measurements (2 for double patterned layers to the reference grid and 1 between the double patterned layers). The requirements of process compatibility, enhanced performance and large number of measurements make the choice of overlay metrology for DPT very challenging. In this work we use different flavors of the standard overlay metrology technique (IBO) as well as the new technique (SCOL) to address these three requirements. The compatibility of the corresponding overlay targets with double patterning processes (Litho-Etch-Litho-Etch (LELE); Litho-Freeze-Litho-Etch (LFLE), Spacer defined) is tested. The process impact on different target types is discussed (CD bias LELE, Contrast for LFLE). We compare the standard imaging overlay metrology with non-standard imaging techniques dedicated to double patterning processes (multilayer imaging targets allowing one overlay target instead of three, very small imaging targets). In addition to standard designs already discussed [1], we investigate SCOL target designs specific to double patterning processes. The feedback to the scanner is determined using the different techniques. The final overlay results obtained are compared accordingly. We conclude with the pros and cons of each technique and suggest the optimal metrology strategy for overlay control in double

  12. Chen’s Double Eyelid Fold Ratio

    PubMed Central

    Chen, Chen-Chia; Tai, Hao-Chih

    2016-01-01

    Background: Double eyelidplasty can construct palpebral folds and enhance beauty perception for Asians with single eyelids. A new palpebral parameter for the quantitative interpretation of surgical outcomes is proposed on the basis of a photometric study of the altered proportions of Asian eyes after double eyelid operation. Methods: A total of 100 Asian adults with single upper eyelids who were satisfied with the enlarged eyes by operation were included in the study. A retrospective measurement of palpebral parameters in the frontal profile both preoperatively and 6 months postoperatively was performed. The proportions of various parameters in the eyebrow–eye aesthetic unit were calculated and analyzed. Results: Double eyelidplasty can augment the vertical dimension of palpebral fissure by 27.9% increase on average. The vertical ratio of palpebral fissure to the eyebrow–eye unit is augmented by 34.4% increase. The vertical ratio of the subunit below double eyelid fold peak to the unit is augmented by 82.6% increase. Conclusions: Double eyelidplasty can substantially enlarge the vertical dimensions of the eyes of Asians with single eyelids. The eyes are perceived to be larger because of the visually assimilated illusion of the superimposed eyelid fold and the relative proportions of the eyebrow–eye unit. The authors propose using a vertical ratio of the subunit below double eyelid fold peak in the eyebrow–eye unit to measure the visually perceived proportion of the eye in the unit. This ratio can be applied clinically for a quantitative evaluation of the surgical outcome after double eyelidplasty. PMID:27200243

  13. The First SLR Double-Difference Baseline

    NASA Astrophysics Data System (ADS)

    Svehla, Drazen; Haagmans, Roger; Floberghagen, Rune; Cacciapuoti, Luigi; Sierk, Bernd; Kirchner, Georg; Rodriguez, Jose; Wilkinson, Matthew; Sherwood, Rob; Appleby, Graham

    2013-04-01

    We introduce the SLR double-difference approach of space geodesy. With real and simulated SLR measurements it is shown how common SLR biases are removed by forming SLR double-differences, i.e. station range biases, common retro-reflector effects and orbit errors (GNSS) for baselines up to e.g. 5000 km. In this way we obtain SLR observables of utmost precision and accuracy. We show how remaining noise in the SLR measurements nicely averages out, leading to orbit-free and bias-free estimation of station coordinates, local ties between different space geodesy techniques and precise comparison of optical/microwave tropospheric effects. It shall be noted that SLR scale is preserved by double-differencing. When ETALON and LAGEOS satellites are observed by SLR, any orbit error propagates directly into estimated station coordinates. However, by forming differences between two satellites and two ground stations this orbit error can be eliminated. Both satellites need to be observed quasi-simultaneously in the same tracking sessions in order that station range bias and common retro-reflector effects are removed by differencing. When SLR measurements from GRZL and HERL SLR stations are taken to GLONASS and LAGEOS satellites and processed in double-difference mode, clear common orbit errors are visible in the SLR residuals from both stations. The same stands for small range biases that are visible between the consecutive observing sessions and are removed by forming SLR baselines. Longer SLR passes reveal other interesting systematic effects common to both stations at mm-level. An error in the order of 4-6 cm RMS was introduced to GNSS orbits, however the effect on station coordinates in negligible over such a short SLR baseline. We show how with just one-two SLR double-difference passes one can estimate station coordinates at mm-level. When in parallel, both GNSS satellites are observed with microwave measurements, one can estimate very accurate local ties by comparing (or

  14. Double Engine for a Nebula

    NASA Astrophysics Data System (ADS)

    2009-08-01

    ESO has just released a stunning new image of a field of stars towards the constellation of Carina (the Keel). This striking view is ablaze with a flurry of stars of all colours and brightnesses, some of which are seen against a backdrop of clouds of dust and gas. One unusual star in the middle, HD 87643, has been extensively studied with several ESO telescopes, including the Very Large Telescope Interferometer (VLTI). Surrounded by a complex, extended nebula that is the result of previous violent ejections, the star has been shown to have a companion. Interactions in this double system, surrounded by a dusty disc, may be the engine fuelling the star's remarkable nebula. The new image, showing a very rich field of stars towards the Carina arm of the Milky Way, is centred on the star HD 87643, a member of the exotic class of B[e] stars [1]. It is part of a set of observations that provide astronomers with the best ever picture of a B[e] star. The image was obtained with the Wide Field Imager (WFI) attached to the MPG/ESO 2.2-metre telescope at the 2400-metre-high La Silla Observatory in Chile. The image shows beautifully the extended nebula of gas and dust that reflects the light from the star. The central star's wind appears to have shaped the nebula, leaving bright, ragged tendrils of gas and dust. A careful investigation of these features seems to indicate that there are regular ejections of matter from the star every 15 to 50 years. A team of astronomers, led by Florentin Millour, has studied the star HD 87643 in great detail, using several of ESO's telescopes. Apart from the WFI, the team also used ESO's Very Large Telescope (VLT) at Paranal. At the VLT, the astronomers used the NACO adaptive optics instrument, allowing them to obtain an image of the star free from the blurring effect of the atmosphere. To probe the object further, the team then obtained an image with the Very Large Telescope Interferometer (VLTI). The sheer range of this set of observations

  15. Re-naming D Double Prime

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    1999-01-01

    "Knowledge about the dynamics of the D double prime region is a key to unlock some fundamental mysteries of the Earth heat engine which governs a wide range of global geophysical processes from tectonics to geodynamo." This benign sentence makes complete sense to many geophysicists. But for many others, it makes sense all except the odd nomenclature "D double prime". One knows about the crust, upper and lower mantle, outer and inner core, but where is the D double prime region? What meaning does it try to convey? Where is D prime region, or D, or A, B, C regions for that matter, and are there higher-order primes? How does such an odd name come about anyway? D double prime, or more "simply" D", is a generic designation given to the thin shell, about 200 km thick, of the lowermost mantle just above the core-mantle boundary inside the Earth. Incidentally, whether D" is "simpler" than "D double prime" depends on whether you are pronouncing it or writing/typing it; and D" can be confusing to readers in distinguishing quotation marks (such as in the above sentences) and second derivatives, and to word processors in spelling check and indexing.

  16. Double tube helical coil steam generator

    SciTech Connect

    Garabedian, G.; De Luca, R.A.

    1987-02-24

    A steam generator is described comprising a container having a closed lower end, divided into longitudinally arranged sections including an uppermost disengaging chamber, an upper plenum, and a lower plenum. The upper plenum is above the lower plenum and contains a multiplicity of double tube helical coils, wherein each of the double tube helical coils is comprised of an inner tube individually enclosed for at least a portion of its length by an outer tube to form a double tube portion and thereby define an annular gap which is outside the inner tube but enclosed by the outer tube; the inner tube being attached at one end to a feedwater inlet, and the inner tube being attached at the other end to a steam outlet; the outer tube being in open communication at both ends with the disengaging chamber; the double tube portion being in the configuration of a helix for part of its length; the upper plenum having no communication with the disengaging chamber and having restricted communication with the lower plenum such that liquid metal entering the upper plenum and flowing to the lower plenum closely contacts at least a portion of the double tube helical coils; and the annular gap being at least partially filled with liquid metal.

  17. A novel mechanism for creating double pulsars

    NASA Technical Reports Server (NTRS)

    Sigurdsson, Steinn; Hernquist, Lars

    1992-01-01

    Simulations of encounters between pairs of hard binaries, each containing a neutron star and a main-sequence star, reveal a new formation mechanism for double pulsars in dense cores of globular clusters. In many cases, the two normal stars are disrupted to form a common envelope around the pair of neutron stars, both of which will be spun up to become millisecond pulsars. We predict that a new class of pulsars, double millisecond pulsars, will be discovered in the cores of dense globular clusters. The genesis proceeds through a short-lived double-core common envelope phase, with the envelope ejected in a fast wind. It is possible that the progenitor may also undergo a double X-ray binary phase. Any circular, short-period double pulsar found in the galaxy would necessarily come from disrupted disk clusters, unlike Hulse-Taylor class pulsars or low-mass X-ray binaries which may be ejected from clusters or formed in the galaxy.

  18. Electron acceleration in stochastic double layers

    NASA Technical Reports Server (NTRS)

    Lotko, William

    1987-01-01

    Transversely localized double layers evolve randomly in turbulent regions of strongly magnetized plasma carrying current along the magnetic field. Results from numerical simulations and spacecraft observations in the auroral plasma indicate that the parallel electric field in such regions is microscopically intermittent or stochastic. The implications of stochastic double layer fields on electron acceleration will be discussed in terms of a statistical process involving ensemble averages over test particle motion. A Fokker-Planck equation can be derived for the electron phase space density, which depends on the mean and rms amplitudes of the double layers, the mean double layer density, and the initial electron velocity distribution. It is shown that the resulting electron acceleration is very sensitive to the ratio of the initial electron energy to the rms double layer amplitude. When this ratio is large, the acceleration process differs little from that expected in a dc electric field. When it is small, stochastic heating competes with directed acceleration. Evidence for both cases can be found in the auroral ionosphere in association with so-called inverted-V precipitation and collimated edge precipitation.

  19. Double-difference adjoint seismic tomography

    NASA Astrophysics Data System (ADS)

    Yuan, Yanhua O.; Simons, Frederik J.; Tromp, Jeroen

    2016-09-01

    We introduce a `double-difference' method for the inversion for seismic wave speed structure based on adjoint tomography. Differences between seismic observations and model predictions at individual stations may arise from factors other than structural heterogeneity, such as errors in the assumed source-time function, inaccurate timings and systematic uncertainties. To alleviate the corresponding non-uniqueness in the inverse problem, we construct differential measurements between stations, thereby reducing the influence of the source signature and systematic errors. We minimize the discrepancy between observations and simulations in terms of the differential measurements made on station pairs. We show how to implement the double-difference concept in adjoint tomography, both theoretically and practically. We compare the sensitivities of absolute and differential measurements. The former provide absolute information on structure along the ray paths between stations and sources, whereas the latter explain relative (and thus higher resolution) structural variations in areas close to the stations. Whereas in conventional tomography a measurement made on a single earthquake-station pair provides very limited structural information, in double-difference tomography one earthquake can actually resolve significant details of the structure. The double-difference methodology can be incorporated into the usual adjoint tomography workflow by simply pairing up all conventional measurements; the computational cost of the necessary adjoint simulations is largely unaffected. Rather than adding to the computational burden, the inversion of double-difference measurements merely modifies the construction of the adjoint sources for data assimilation.

  20. Temperature-stable double SAW resonators.

    PubMed

    Martin, Guenter; Kunze, Reinhard; Wall, Bert

    2008-01-01

    The temperature stability of SAW resonators on quartz can be enhanced by means of double resonators. The turnover temperatures of the double resonators' components, called single resonators, are positioned above and below room temperature. As a consequence, the temperature coefficients of frequency of the 1st order (TCF1) have opposite signs at room temperature, leading to the vanishing TCF1 of the double resonators. Frequently, different turnover temperatures are adjusted by different propagation directions on an ST cut of quartz. An overview of known and new methods for compensating the temperature coefficient of frequency of the 2nd order (TCF2) of two-port and one-port SAW double resonators is given. A concept by means of which temperature-stable circuits of single resonators are found is described. Two types of temperature-stable double resonators found by applying that concept are treated in detail: 1) a two-port resonator composed of two cascaded two-port resonators and a coupling inductance, and 2) a one-port resonator comprising a series connection of one-port resonators with an inductance in parallel with each single resonator. The substrates are 35.5 degrees rotY cuts of quartz. In both cases, the shift of resonance frequency within the temperature range from -30 degrees C to 70 degrees C is smaller than 20 ppm.

  1. The Double Counting Problem in Neighborhood Scale Air Quality Modeling

    NASA Astrophysics Data System (ADS)

    Du, S.; Hughes, V.; Woodhouse, L.; Servin, A.

    2004-12-01

    Air quality varies considerably within megacities. In certain neighborhoods concentrations of toxic air contaminants (TACs) can be appreciably higher than that in other neighborhoods of the same city. These pockets of high concentrations are associated with both transport of TACs from other areas and local emissions. In order to assess the health risks imposed by TACs at neighborhood scale and to develop strategies of abatement, neighborhood scale air quality modeling is needed. In 1999, the California Air Resources Board (ARB) established the Neighborhood Assessment Program (NAP) - a program designed to develop assessment tools for evaluating and understanding air quality in California communities. As part of the Neighborhood Assessment Program, ARB is conducting research on neighborhood-scale modeling methodologies. Two criteria are suggested to select a neighborhood scale air quality modeling system that can be used to assess concentrations of TACs: scientific soundness and balancing computational requirements. The latter criterion ensures that as many interested parties as possible can participate the process of air quality modeling so that they have a better understanding of air quality issues and make best use of air quality modeling results in their neighborhoods. Based on these two selection criteria a hybrid approach is recommended. This hybrid approach is a combination of using both a regional scale air quality model to assess the contributions from sources that are not located within the neighborhood of interest and a microscale model to assess the impact from the local sources that are within the neighborhood. However, one of the modeling system selection criteria, balancing computational requirements, dictates that all sources (both within and outside the neighborhood of interest) must be included in the regional scale modeling. A potential problem, referred to as double counting, arises because some local sources are included in both regional and

  2. HANFORD DOUBLE SHELL TANK (DST) THERMAL & SEISMIC PROJECT SEISMIC ANALYSIS OF HANFORD DOUBLE SHELL TANKS

    SciTech Connect

    MACKEY, T.C.

    2006-03-17

    M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratory (PNNL) to perform seismic analysis of the Hanford Site double-shell tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project--DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST system at Hanford in support of Tri-Party Agreement Milestone M-48-14, The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). The work statement provided to M&D (PNNL 2003) required that the seismic analysis of the DSTs assess the impacts of potentially non-conservative assumptions in previous analyses and account for the additional soil mass due to the as-found soil density increase, the effects of material degradation, additional thermal profiles applied to the full structure including the soil-structure response with the footings, the non-rigid (low frequency) response of the tank roof, the asymmetric seismic-induced soil loading, the structural discontinuity between the concrete tank wall and the support footing and the sloshing of the tank waste. The seismic analysis considers the interaction of the tank with the surrounding soil and the effects of the primary tank contents. The DSTs and the surrounding soil are modeled as a system of finite elements. The depth and width of the soil incorporated into the analysis model are sufficient to obtain appropriately accurate analytical results. The analyses required to support the work statement differ from previous analysis of the DSTs in that the soil-structure interaction (SSI) model includes several (nonlinear) contact surfaces in the tank structure, and the contained waste must be modeled explicitly in order to capture the fluid-structure interaction behavior between the primary tank and contained

  3. High power double-scale pulses from a gain-guided double-clad fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Haitao; Gao, Gan; Li, Qinghua; Gong, Mali

    2017-03-01

    Generation of high power double-scale pulses from a gain-guided double-clad fiber laser is experimentally demonstrated. By employing the Yb-doped 10/130 double-clad fiber as the gain medium, the laser realizes an output power of 5.1 W and pulse energy of 0.175 µJ at repetition rate of 29.14 MHz. To the best of our knowledge, this average output power is the highest among the reported double-scale pulse oscillators. The autocorrelation trace of pulses contains the short (98 fs) and long (29.5 ps) components, and the spectral bandwidth of the pulse is 27.3 nm. Such double-scale pulses are well suited for seeding the high power MOPA (master oscillator power amplifier) systems, nonlinear frequency conversion and optical coherence tomography.

  4. CLAS: Assessing the Assessment.

    ERIC Educational Resources Information Center

    Hansen, Bobbi

    1994-01-01

    Asserts that assessment has become a leading national educational issue. Presents a chronology of events in California related to student assessment reform. Identifies the California Learning Assessment System (CLAS) three key elements: (1) individual student scores; (2) performance testing; and (3) curriculum improvement. (CFR)

  5. Double Planet Meets Triple Star

    NASA Astrophysics Data System (ADS)

    2002-08-01

    High-Resolution VLT Image of Pluto Event on July 20, 2002 A rare celestial phenomenon involving the distant planet Pluto has occurred twice within the past month. Seen from the Earth, this planet moved in front of two different stars on July 20 and August 21, respectively, providing observers at various observatories in South America and in the Pacific area with a long awaited and most welcome opportunity to learn more about the tenuous atmosphere of that cold planet. On the first date, a series of very sharp images of a small sky field with Pluto and the star was obtained with the NAOS-CONICA (NACO) adaptive optics (AO) camera mounted on the ESO VLT 8.2-m YEPUN telescope at the Paranal Observatory. With a diameter of about 2300 km, Pluto is about six times smaller than the Earth. Like our own planet, it possesses a relatively large moon, Charon , measuring 1200 km across and circling Pluto at a distance of about 19,600 km once every 6.4 days. In fact, because of the similarity of the two bodies, the Pluto-Charon system is often referred to as a double planet . At the current distance of nearly 4,500 million km from the Earth, Pluto's disk subtends a very small angle in the sky, 0.107 arcsec. It is therefore very seldom that Pluto - during its orbital motion - passes exactly in front of a comparatively bright star. Such events are known as "occultations" , and it is difficult to predict exactly when and where on the Earth's surface they are visible. Stellar occultations When Pluto moves in front of a star, it casts a "shadow" on the Earth's surface within which an observer cannot see the star, much like the Earth's Moon hides the Sun during a total solar eclipse. During the occultation event, Pluto's "shadow" also moves across the Earth's surface. The width of this shadow is equal to Pluto's diameter, i.e. about 2300 km. One such occultation event was observed in 1988, and two others were expected to occur in 2002, according to predictions published in 2000 by

  6. The Dissolution of Double Holliday Junctions

    PubMed Central

    Bizard, Anna H.; Hickson, Ian D.

    2014-01-01

    Double Holliday junctions (dHJS) are important intermediates of homologous recombination. The separate junctions can each be cleaved by DNA structure-selective endonucleases known as Holliday junction resolvases. Alternatively, double Holliday junctions can be processed by a reaction known as “double Holliday junction dissolution.” This reaction requires the cooperative action of a so-called “dissolvasome” comprising a Holliday junction branch migration enzyme (Sgs1/BLM RecQ helicase) and a type IA topoisomerase (Top3/TopoIIIα) in complex with its OB (oligonucleotide/oligosaccharide binding) fold containing accessory factor (Rmi1). This review details our current knowledge of the dissolution process and the players involved in catalyzing this mechanistically complex means of completing homologous recombination reactions. PMID:24984776

  7. Machine learning bandgaps of double perovskites

    NASA Astrophysics Data System (ADS)

    Pilania, Ghanshyam; Mannodi-Kanakkithodi, Arun; Uberuaga, Blas; Ramprasad, Rampi; Gubernatis, James; Lookman, Turab

    The ability to make rapid and accurate predictions of bandgaps for double perovskites is of much practical interest for a range of applications. While quantum mechanical computations for high-fidelity bandgaps are enormously computation-time intensive and thus impractical in high throughput studies, informatics-based statistical learning approaches can be a promising alternative. Here we demonstrate a systematic feature-engineering approach and a robust learning framework for efficient and accurate predictions of electronic bandgaps for double perovskites. After evaluating a set of nearly 1.2 million features, we identify several elemental features of the constituent atomic species as the most crucial and relevant predictors. The developed models are validated and tested using the best practices of data science (on a dataset of more than 1300 double perovskite bandgaps) and further analyzed to rationalize their prediction performance. Los Alamos National Laboratory LDRD program and the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

  8. Double Dirac Semimetals in Three Dimensions.

    PubMed

    Wieder, Benjamin J; Kim, Youngkuk; Rappe, A M; Kane, C L

    2016-05-06

    We study a class of Dirac semimetals that feature an eightfold-degenerate double Dirac point. We show that 7 of the 230 space groups can host such Dirac points and argue that they all generically display linear dispersion. We introduce an explicit tight-binding model for space groups 130 and 135. Space group 135 can host an intrinsic double Dirac semimetal with no additional states at the Fermi energy. This defines a symmetry-protected topological critical point, and we show that a uniaxial compressive strain applied in different directions leads to topologically distinct insulating phases. In addition, the double Dirac semimetal can accommodate topological line defects that bind helical modes. Connections are made to theories of strongly interacting filling-enforced semimetals, and potential materials realizations are discussed.

  9. Double Dirac Semimetals in Three Dimensions

    NASA Astrophysics Data System (ADS)

    Wieder, Benjamin J.; Kim, Youngkuk; Rappe, A. M.; Kane, C. L.

    2016-05-01

    We study a class of Dirac semimetals that feature an eightfold-degenerate double Dirac point. We show that 7 of the 230 space groups can host such Dirac points and argue that they all generically display linear dispersion. We introduce an explicit tight-binding model for space groups 130 and 135. Space group 135 can host an intrinsic double Dirac semimetal with no additional states at the Fermi energy. This defines a symmetry-protected topological critical point, and we show that a uniaxial compressive strain applied in different directions leads to topologically distinct insulating phases. In addition, the double Dirac semimetal can accommodate topological line defects that bind helical modes. Connections are made to theories of strongly interacting filling-enforced semimetals, and potential materials realizations are discussed.

  10. Double mode Cepheids in M31

    SciTech Connect

    Poleski, Radosław

    2013-12-01

    Until now, double mode Cepheids (or beat Cepheids) were known only in the Galaxy, the Magellanic Clouds, and M33. Curiously, none of the more than 2000 Cepheids in M31 was claimed to show two pulsation modes. We conducted a systematic search for double mode Cepheids in the archival data of M31 and discovered four such objects. We identify one of the stars as a first and second overtone pulsator even though its secondary period is subject to strong aliasing. Two stars pulsate in the fundamental mode and the first overtone. Their fundamental periods are 9.392 days and 9.163 days. This makes them the first candidates for fundamental mode and first overtone Cepheids, of which double mode pulsations are caused by the 2:1 resonance of the fundamental mode and the second overtone.

  11. Double Ramification Cycles and Quantum Integrable Systems

    NASA Astrophysics Data System (ADS)

    Buryak, Alexandr; Rossi, Paolo

    2016-03-01

    In this paper, we define a quantization of the Double Ramification Hierarchies of Buryak (Commun Math Phys 336:1085-1107, 2015) and Buryak and Rossi (Commun Math Phys, 2014), using intersection numbers of the double ramification cycle, the full Chern class of the Hodge bundle and psi-classes with a given cohomological field theory. We provide effective recursion formulae which determine the full quantum hierarchy starting from just one Hamiltonian, the one associated with the first descendant of the unit of the cohomological field theory only. We study various examples which provide, in very explicit form, new (1+1)-dimensional integrable quantum field theories whose classical limits are well-known integrable hierarchies such as KdV, Intermediate Long Wave, extended Toda, etc. Finally, we prove polynomiality in the ramification multiplicities of the integral of any tautological class over the double ramification cycle.

  12. Double Glow Plasma Surface Alloying Antibacterial Silver Coating on Pure Titanium

    NASA Astrophysics Data System (ADS)

    Lin, Naiming; Guo, Junwen; Hang, Ruiqiang; Zou, Jiaojuan; Tang, Bin

    2014-03-01

    In order to endow the commercial pure titanium dental implant material with antibacterial property and aimed at avoiding the invalidation that is caused by bacterial adhesion on the surface, a silver coating was fabricated via double glow plasma surface alloying. The antibacterial property of the silver coating was assessed via in vitro estimation. The results showed that a continuous and compact coating was formed. The silver coating had absolute superiority in antibacterial property to raw commercial pure titanium. Double glow plasma surface alloying with silver on commercial pure titanium dental implant material could be considered as a potentially effective method for preventing bacterial adhesion.

  13. Double Glow Plasma Surface Alloying Antibacterial Silver Coating on Pure Titanium

    NASA Astrophysics Data System (ADS)

    Lin, Naiming; Guo, Junwen; Hang, Ruiqiang; Zou, Jiaojuan; Tang, Bin

    2014-12-01

    In order to endow the commercial pure titanium dental implant material with antibacterial property and aimed at avoiding the invalidation that is caused by bacterial adhesion on the surface, a silver coating was fabricated via double glow plasma surface alloying. The antibacterial property of the silver coating was assessed via in vitro estimation. The results showed that a continuous and compact coating was formed. The silver coating had absolute superiority in antibacterial property to raw commercial pure titanium. Double glow plasma surface alloying with silver on commercial pure titanium dental implant material could be considered as a potentially effective method for preventing bacterial adhesion.

  14. Isolation and characterization of eight novel microsatellite loci in the double-crested cormorant (Phalacrocorax auritus)

    USGS Publications Warehouse

    Mercer, Dacey; Haig, Susan; Mullins, Thomas

    2010-01-01

    We describe the isolation and characterization of eight microsatellite loci from the double-crested cormorant (Phalacrocorax auritus). Genetic variability was assessed using 60 individuals from three populations. All loci were variable with the number of alleles ranging from two to 17 per locus, and observed heterozygosity varying from 0.05 to 0.89. No loci showed signs of linkage disequilibrium and all loci conformed to Hardy–Weinberg equilibrium frequencies. Further, all loci amplified and were polymorphic in two related Phalacrocorax species. These loci should prove useful for population genetic studies of the double-crested cormorant and other pelecaniform species.

  15. Period-Doubling Bifurcation in Nonlinear Systems

    NASA Astrophysics Data System (ADS)

    Mao, Jian-Min

    The dependence of the critical exponents, such as the Feigenbaum ratios, of the period-doubling bifurcation on the order of critical point z is studied. The dependence is quantitatively given for one-dimensional dissipative maps. The scaling factor in the period-doubling power spectrum of a class of two-dimensional area-preserving maps is found to approach a universal limit by both fast Fourier transform and autocorrelation-function analysis. The dependence of the fractal dimension on the critical-point order is studied. The variation of the three most commonly used definitions of dimension, viz., the capacity, the information dimension, and the correlation exponent, is computed as a function of z. The numerical values agree very well with analytical estimates. The dependence of the scaling of the period-doubling bifurcation on the dimensionality of the reduced phase space is considered. Especially, the investigation of period-doubling bifurcations in four-dimensional symplectic maps indicates the existence of an universally self-similar period-doubling sequence. The fixed-point map has two unstable directions under the period-doubling operator with two relevant eigenvalues. The four orbital scaling factors have been found. As an extension of the Feigenbaum scaling law for parameter and orbital element, a many-term scaling law is suggested. For one-dimensional dissipative maps, two-dimensional area-preserving maps, and four-dimensional symplectic maps, the many-term scaling law is very well obeyed. New scaling factors have been found.

  16. Hamilton Jeffers and the Double Star Catalogues

    NASA Astrophysics Data System (ADS)

    Tenn, Joseph S.

    2013-01-01

    Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Court reporter and amateur astronomer Shelburne Wesley Burnham (1838-1921) published a massive double star catalogue containing more than 13,000 systems in 1906. The next keeper of the double stars was Lick Observatory astronomer Robert Grant Aitken (1864-1951), who produced a much larger catalogue in 1932. Aitken maintained and expanded Burnham’s records of observations on handwritten file cards, eventually turning them over to Lick Observatory astrometrist Hamilton Moore Jeffers (1893-1976). Jeffers further expanded the collection and put all the observations on punched cards. With the aid of Frances M. "Rete" Greeby (1921-2002), he made two catalogues: an Index Catalogue with basic data about each star, and a complete catalogue of observations, with one observation per punched card. He enlisted Willem van den Bos of Johannesburg to add southern stars, and they published the Index Catalogue of Visual Double Stars, 1961.0. As Jeffers approached retirement he became greatly concerned about the disposition of the catalogues. He wanted to be replaced by another "double star man," but Lick Director Albert E. Whitford (1905-2002) had the new 120-inch reflector, the world’s second largest telescope, and he wanted to pursue modern astrophysics instead. Jeffers was vociferously opposed to turning over the card files to another institution, and especially against their coming under the control of Kaj Strand of the U.S. Naval Observatory. In the end the USNO got the files and has maintained the records ever since, first under Charles Worley (1935-1997), and, since 1997, under Brian Mason. Now called the Washington Double Star Catalog (WDS), it is completely online and currently contains more than 1,000,000 measures of more than 100,000 pairs.

  17. Double conformal space-time algebra

    NASA Astrophysics Data System (ADS)

    Easter, Robert Benjamin; Hitzer, Eckhard

    2017-01-01

    The Double Conformal Space-Time Algebra (DCSTA) is a high-dimensional 12D Geometric Algebra G 4,8that extends the concepts introduced with the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA) G 8,2 with entities for Darboux cyclides (incl. parabolic and Dupin cyclides, general quadrics, and ring torus) in spacetime with a new boost operator. The base algebra in which spacetime geometry is modeled is the Space-Time Algebra (STA) G 1,3. Two Conformal Space-Time subalgebras (CSTA) G 2,4 provide spacetime entities for points, flats (incl. worldlines), and hyperbolics, and a complete set of versors for their spacetime transformations that includes rotation, translation, isotropic dilation, hyperbolic rotation (boost), planar reflection, and (pseudo)spherical inversion in rounds or hyperbolics. The DCSTA G 4,8 is a doubling product of two G 2,4 CSTA subalgebras that inherits doubled CSTA entities and versors from CSTA and adds new bivector entities for (pseudo)quadrics and Darboux (pseudo)cyclides in spacetime that are also transformed by the doubled versors. The "pseudo" surface entities are spacetime hyperbolics or other surface entities using the time axis as a pseudospatial dimension. The (pseudo)cyclides are the inversions of (pseudo)quadrics in rounds or hyperbolics. An operation for the directed non-uniform scaling (anisotropic dilation) of the bivector general quadric entities is defined using the boost operator and a spatial projection. DCSTA allows general quadric surfaces to be transformed in spacetime by the same complete set of doubled CSTA versor (i.e., DCSTA versor) operations that are also valid on the doubled CSTA point entity (i.e., DCSTA point) and the other doubled CSTA entities. The new DCSTA bivector entities are formed by extracting values from the DCSTA point entity using specifically defined inner product extraction operators. Quadric surface entities can be boosted into moving surfaces with constant velocities that display the length

  18. Superballistic wavepacket spreading in double kicked rotors

    NASA Astrophysics Data System (ADS)

    Fang, Ping; Wang, Jiao

    2016-08-01

    We investigate possible ways in which a quantum wavepacket spreads. We show that in a general class of double kicked rotor system, a wavepacket may undergo superballistic spreading; i.e., its variance increases as the cubic of time. The conditions for the observed superballistic spreading and two related characteristic time scales are studied. Our results suggest that the symmetry of the studied model and whether it is a Kolmogorov-Arnold-Moser system are crucial to its wavepacket spreading behavior. Our study also sheds new light on the exponential wavepacket spreading phenomenon previously observed in the double kicked rotor system.

  19. Double photoionization of hydrocarbons and aromatic molecules

    NASA Astrophysics Data System (ADS)

    Wehlitz, R.

    2016-11-01

    This article reviews the recent progress in the field of double photoionization of hydrocarbons and aromatic molecules using synchrotron radiation. First I will describe the importance of carbon-based molecules, which are all around us and are literally part of our life. They exhibit intriguing properties some of which can be probed via double photoionization, i.e., the simultaneous emission of two electrons. Furthermore, I will discuss the different mechanisms that can lead to a doubly charged organic molecule and will highlight those findings by comparing them with the results for atoms and other (simple) molecules. Finally, I will give an outlook on future directions on this subject.

  20. The double-beta decay: Theoretical challenges

    SciTech Connect

    Horoi, Mihai

    2012-11-20

    Neutrinoless double beta decay is a unique process that could reveal physics beyond the Standard Model of particle physics namely, if observed, it would prove that neutrinos are Majorana particles. In addition, it could provide information regarding the neutrino masses and their hierarchy, provided that reliable nuclear matrix elements can be obtained. The two neutrino double beta decay is an associate process that is allowed by the Standard Model, and it was observed for about ten nuclei. The present contribution gives a brief review of the theoretical challenges associated with these two process, emphasizing the reliable calculation of the associated nuclear matrix elements.

  1. Molecular mechanism of double Holliday junction dissolution

    PubMed Central

    2014-01-01

    Processing of homologous recombination intermediates is tightly coordinated to ensure that chromosomal integrity is maintained and tumorigenesis avoided. Decatenation of double Holliday junctions, for example, is catalysed by two enzymes that work in tight coordination and belong to the same ‘dissolvasome’ complex. Within the dissolvasome, the RecQ-like BLM helicase provides the translocase function for Holliday junction migration, while the topoisomerase III alpha-RMI1 subcomplex works as a proficient DNA decatenase, together resulting in double-Holliday-junction unlinking. Here, we review the available architectural and biochemical knowledge on the dissolvasome machinery, with a focus on the structural interplay between its components. PMID:25061510

  2. Probing Angular Correlations in Sequential Double Ionization

    SciTech Connect

    Fleischer, A.; Woerner, H. J.; Arissian, L.; Liu, L. R.; Meckel, M.; Rippert, A.; Doerner, R.; Villeneuve, D. M.; Corkum, P. B.; Staudte, A.

    2011-09-09

    We study electron correlation in sequential double ionization of noble gas atoms and HCl in intense, femtosecond laser pulses. We measure the photoelectron angular distributions of Ne{sup +} relative to the first electron in a pump-probe experiment with 8 fs, 800 nm, circularly polarized laser pulses at a peak intensity of a few 10{sup 15} W/cm{sup 2}. Using a linear-linear pump-probe setup, we further study He, Ar, and HCl. We find a clear angular correlation between the two ionization steps in the sequential double ionization intensity regime.

  3. Probabilistic double guarantee kidnapping detection in SLAM.

    PubMed

    Tian, Yang; Ma, Shugen

    2016-01-01

    For determining whether kidnapping has happened and which type of kidnapping it is while a robot performs autonomous tasks in an unknown environment, a double guarantee kidnapping detection (DGKD) method has been proposed. The good performance of DGKD in a relative small environment is shown. However, a limitation of DGKD is found in a large-scale environment by our recent work. In order to increase the adaptability of DGKD in a large-scale environment, an improved method called probabilistic double guarantee kidnapping detection is proposed in this paper to combine probability of features' positions and the robot's posture. Simulation results demonstrate the validity and accuracy of the proposed method.

  4. An acoustic double fishnet using Helmholtz resonators.

    PubMed

    Murray, A R J; Summers, I R; Sambles, J R; Hibbins, A P

    2014-09-01

    The acoustic transmission of a closely spaced pair of patterned and perforated rigid plates is explored in air. The structure resembles an acoustic double fishnet design, with each plate modified such that the gap between them acts as an array of Helmholtz resonators. This allows the center frequency of the stop band to be reduced by a factor greater than 2 from the value obtained for the conventional acoustic double fishnet design. Experimental results accord well with the predictions of a finite element model.

  5. Higher spin double field theory: a proposal

    NASA Astrophysics Data System (ADS)

    Bekaert, Xavier; Park, Jeong-Hyuck

    2016-07-01

    We construct a double field theory coupled to the fields present in Vasiliev's equations. Employing the "semi-covariant" differential geometry, we spell a functional in which each term is completely covariant with respect to O(4, 4) T-duality, doubled diffeomorphisms, Spin(1, 3) local Lorentz symmetry and, separately, HS(4) higher spin gauge symmetry. We identify a minimal set of BPS-like conditions whose solutions automatically satisfy the full Euler-Lagrange equations. As such a solution, we derive a linear dilaton vacuum. With extra algebraic constraints further supplemented, the BPS-like conditions reduce to the bosonic Vasiliev equations.

  6. Magic-angle turning with double acquisition

    NASA Astrophysics Data System (ADS)

    Matsunaga, Tatsuya; Takegoshi, K.

    2017-01-01

    The double-acquisition scheme for efficient data collection of hypercomplex data (the States method) of a two-dimensional experiment is adopted to magic-angle hopping (MAH) and magic-angle turning (MAT) experiments, which are powerful methods to measure the principal values of the chemical shift anisotropy (CSA) in a powder sample. It is shown that the double acquisition MAT (DAMAT) sequence realizes the S/N ratio comparable to or better than those of other variants of the MAH/MAT sequences. In addition, we show that DAMAT has preferable features that there are no spinning sidebands in the indirect dimension, and no spectral shearing is necessary.

  7. Otto Stern and the double bank shot

    NASA Astrophysics Data System (ADS)

    Zare, R. N.

    1988-06-01

    In analogy to a double surface scattering study of Estermann, Frisch and Stern for selecting and detecting the velocity of a beam of particles, it is proposed to use double surface scattering to investigate the collision dynamics of a beam of polarized particles with a known surface. In this proposed experiment, the first surface scattering event prepares a polarized (aligned/oriented) beam of particles, and the second surface scattering event permits the measurement of how the polarized beam interacts with the surface under study.

  8. Double phase conjugation in tungsten bronze crystals.

    PubMed

    Sharp, E J; Clark Iii, W W; Miller, M J; Wood, G L; Monson, B; Salamo, G J; Neurgaonkar, R R

    1990-02-20

    In this paper we report a new method for double phase conjugation particularly suited to the tungsten bronze crystal strontium barium niobate. It has also been observed to produce conjugate waves in BaTiO(3) and BSKNN. This new arrangement is called the bridge conjugator because the two beams enter opposing [100] crystal faces and fan together to form a bridge without reflection off a crystal face. Our measurements indicate that the bridge conjugator is competitive with previously reported double phase conjugate mirrors in reflectivity, response time, ease of alignment, and fidelity.

  9. Double-Beta Decay at TUNL

    NASA Astrophysics Data System (ADS)

    Kidd, Mary

    2007-10-01

    Studying double-beta decay at Triangle Universities Nuclear Laboratory (TUNL) is perhaps one of the most promising ways to pinpoint the neutrino mass. What they do not mention is that to study double-beta decay, you probably have to become a certified miner, and if you have a fear of goats, you should stay away. In this talk, I will tell you some of my experiences as a TUNL graduate student, and how I am now nearly qualified for a job in the mining industry.

  10. Magic-angle turning with double acquisition.

    PubMed

    Matsunaga, Tatsuya; Takegoshi, K

    2017-01-01

    The double-acquisition scheme for efficient data collection of hypercomplex data (the States method) of a two-dimensional experiment is adopted to magic-angle hopping (MAH) and magic-angle turning (MAT) experiments, which are powerful methods to measure the principal values of the chemical shift anisotropy (CSA) in a powder sample. It is shown that the double acquisition MAT (DAMAT) sequence realizes the S/N ratio comparable to or better than those of other variants of the MAH/MAT sequences. In addition, we show that DAMAT has preferable features that there are no spinning sidebands in the indirect dimension, and no spectral shearing is necessary.

  11. de Sitter and double asymmetric brane worlds

    SciTech Connect

    Guerrero, Rommel; Rodriguez, R. Omar; Torrealba, Rafael

    2005-12-15

    Asymmetric brane worlds with dS expansion and static double kink topology are obtained from a recently proposed method and their properties are analyzed. These domain walls interpolate between two spacetimes with different cosmological constants. In the dynamic case, the vacua correspond to dS and AdS geometry, unlike the static case where they correspond to AdS background. We show that it is possible to confine gravity on such branes. In particular, the double-brane world hosts two different walls, so that the gravity is localized on one of them.

  12. Global prevalence of double Benioff zones.

    PubMed

    Brudzinski, Michael R; Thurber, Clifford H; Hacker, Bradley R; Engdahl, E Robert

    2007-06-08

    Double Benioff zones provide opportunities for insight into seismogenesis because the underlying mechanism must explain two layers of deep earthquakes and the separation between them. We characterize layer separation inside subducting plates with a coordinate rotation to calculate the slab-normal distribution of earthquakes. Benchmark tests on well-established examples confirm that layer separation is accurately quantified with global seismicity catalogs alone. Global analysis reveals double Benioff zones in 30 segments, including all 16 subduction zones investigated, with varying subducting plate ages and stress orientations, which implies that they are inherent in subducting plates. Layer separation increases with age and is more consistent with dehydration of antigorite than chlorite.

  13. BLOCKING OSCILLATOR DOUBLE PULSE GENERATOR CIRCUIT

    DOEpatents

    Haase, J.A.

    1961-01-24

    A double-pulse generator, particuiarly a double-pulse generator comprising a blocking oscillator utilizing a feedback circuit to provide means for producing a second pulse within the recovery time of the blocking oscillator, is described. The invention utilized a passive network which permits adjustment of the spacing between the original pulses derived from the blocking oscillator and further utilizes the original pulses to trigger a circuit from which other pulses are initiated. These other pulses are delayed and then applied to the input of the blocking oscillator, with the result that the output from the oscillator circuit contains twice the number of pulses originally initiated by the blocking oscillator itself.

  14. Double Flow Bioreactor for In Vitro Test of Drug Delivery.

    PubMed

    Pavia, Francesco Carfì; La Carrubba, Vincenzo; Ghersi, Giulio; Greco, Silvia; Brucato, Valerio

    2017-01-01

    In this work, double-structured polymeric scaffolds were produced, and a double flow bioreactor was designed and set up in order to create a novel system to carry out advanced in vitro drug delivery tests. The scaffolds, consisting of a cylindrical porous matrix, are able to host cells, thus mimicking a three-dimensional tumor mass: moreover, a "pseudo-vascular" structure was embedded into the matrix, with the aim of allowing a flow circulation. The structure that emulates a blood vessel is a porous tubular-shaped scaffold prepared by Diffusion Induced Phase Separation (DIPS), with an internal lumen of 2 mm and a wall thickness of 200 micrometers. The as-prepared vessel was incorporated into a three-dimensional matrix, prepared by Thermally Induced Phase Separation (TIPS), characterized by a high porosity (about 95%) and pore size adequate to accommodate tumor cells and/or mesenchymal cells. The morphology of the multifunctional scaffolds is easy-tunable in terms of pore size, porosity and thickness and therefore adaptable to various cell or tissue types. At the same time, a double flow bioreactor was designed and built up, in order to be able to carry out biological tests on the scaffold under dynamic conditions. The device allows a separate control of the two flows (one for the tubular scaffold, one for the porous matrix) through the scaffolds. Preliminary characterizations and tests carried out suggest the presented system as a candidate to suitably "in vitro" assess the effects of different drugs on various cell populations.

  15. On the trail of double peak hydrographs

    NASA Astrophysics Data System (ADS)

    Martínez-Carreras, Núria; Hissler, Christophe; Gourdol, Laurent; Klaus, Julian; Juilleret, Jérôme; François Iffly, Jean; McDonnell, Jeffrey J.; Pfister, Laurent

    2016-04-01

    A double peak hydrograph features two peaks as a response to a unique rainfall pulse. The first peak occurs at the same time or shortly after the precipitation has started and it corresponds to a fast catchment response to precipitation. The delayed peak normally starts during the recession of the first peak, when the precipitation has already ceased. Double peak hydrographs may occur for various reasons. They can occur (i) in large catchments when lag times in tributary responses are large, (ii) in urban catchments where the first peak is often caused by direct surface runoff on impervious land cover, and the delayed peak to slower subsurface flow, and (iii) in non-urban catchments, where the first and the delayed discharge peaks are explained by different runoff mechanisms (e.g. overland flow, subsurface flow and/or deep groundwater flow) that have different response times. Here we focus on the third case, as a formal description of the different hydrological mechanisms explaining these complex hydrological dynamics across catchments with diverse physiographic characteristics is still needed. Based on a review of studies documenting double peak events we have established a formal classification of catchments presenting double peak events based on their regolith structure (geological substratum and/or its weathered products). We describe the different hydrological mechanisms that trigger these complex hydrological dynamics across each catchment type. We then use hydrometric time series of precipitation, runoff, soil moisture and groundwater levels collected in the Weierbach (0.46 km2) headwater catchment (Luxembourg) to better understand double peak hydrograph generation. Specifically, we aim to find out (1) if the generation of a double peak hydrograph is a threshold process, (2) if the hysteretic relationships between storage and discharge are consistent during single and double peak hydrographs, and (3) if different functional landscape units (the hillslopes

  16. Manual Replacement of Double J Stent Without Fluoroscopy (Double j stent replacement).

    PubMed

    Kose, Osman; Gorgel, Sacit Nuri; Ozbir, Sait; Yenigurbuz, Sekan; Kara, Cengiz

    2015-02-01

    It is not always possible to replace a ureteric stent with a new one due to the fact that tumoral effect increases in ureter with time. We present our experience of manual replacement of double J stent without fluoroscopy. The data from 23 female patients who underwent double J stent replacement with a total of 110 times was retrospectively analyzed. The steps of technique are as follows: take out distal end of the double J stent through urethra to external urethral meatus cystoscopically, insert a 0.035-inch guide wire through double J stent to the renal pelvis or intra pelvicaliceal system, take out old double J stent over guide wire, slide new stent over guide wire and at external meatus level take out guide wire while gently sliding distal end of double J stent over guide wire into urethra. The mean age was 58.39 ± 9.21 years. Cervical, endometrial, and ovarian cancer were diagnosed in 16, 4, and 3 patients respectively. The mean follow-up and indwelling period were 13.8 ± 5.2, 3.8 ± 0.6 months, respectively. Increased pelvicaliceal dilatation, serum creatinine level, or renal parenchymal loss was not observed. Replacement of double J stents with this technique is easy and can be used successfully in distal ureteral obstructions.

  17. Understanding Rotation about a C=C Double Bond

    NASA Astrophysics Data System (ADS)

    Barrows, Susan E.; Eberlein, Thomas H.

    2005-09-01

    In this article, twisting about the C=C double bond and the consequential pyramidalization of sp 2 carbon atoms in alkenes were examined in a molecular modeling study using trans -2-butene as a model system. According to our trans -2-butene model and other similar work, most of the strength of a π bond is retained upon twisting, even for remarkably large C C=C C dihedral angles (up to 90°). The phenomenon of sp 2 carbon atom pyramidalization and preservation of π bond strength upon twisting a C=C double bond is well established in the literature, but is rarely discussed in introductory textbooks. This absence is noteworthy because profound manifestations of this effect do occur in compounds that are covered in an introductory organic chemistry curriculum. We present a simple method of introducing the concept of a flexible C=C π bond into beginning organic chemistry courses. We report the energetic demands of partial twisting about the C=C bond in 2-butene as calculated using DFT, LMP2, and MCSCF methods. Finally, using the results of these calculations, we assessed the degree of strain introduced by the twisted nature of the C=C bond in trans cycloalkenes.

  18. System specification for the double shell tank (DST) system

    SciTech Connect

    GRENARD, C.E.

    2001-10-01

    This document establishes functional, performance, design, development, interface, and test requirements for the Double-Shell Tank System.This specification establishes the functional, performance, design, development, interface, and test requirements for the Double-Shell Tank (DST) System segment, herein referred to as the system or the DST System, located at the Hanford Site in Washington State. This version of the specification establishes system-level requirements for the DST System that are applicable to the River Protection Project (RPP) mission described in HNF-SD-WM-MAR-008, Tank Waste Remediation System Mission Analysis Report. This specification will be used as the basis for assessing the existing DST System against the needs of the mission and as the basis for developing subsysted component specifications. The requirements of this specification will be allocated (in whole or in part) to subsystems and components as further analysis and system definition dictate. Further the federal and state requirements, local ordinances, RPP procedures, and National Consensus Codes and Standards called-out herein will be tailored for use and applicability in the subsystem specifications created for line item project conceptual design activities.

  19. Doppler echocardiographic description of double-inlet left ventricle in an Arabian horse.

    PubMed

    Sedacca, Cassidy D; Bright, Janice M; Boon, June

    2010-08-01

    Univentricular atrioventricular (AV) connections are rare and complex congenital cardiac anomalies in which both AV valves communicate into a large, common (single) receiving chamber. The common chamber can be of left, right, or mixed ventricular morphology. Although well documented in people, reports of the double-inlet ventricle malformation are rare in the veterinary literature. This report provides description of an Arabian horse with a double-inlet univentricular connection of left ventricular type, a hypoplastic subpulmonary right ventricle, two muscular ventricular septal defects, and a stenotic mitral valve. Transthoracic Doppler echocardiography enabled antemortem diagnosis, and provided an assessment of intracardiac hemodynamics. The findings indicate that Doppler echocardiography is a useful, noninvasive tool for evaluating equine patients with congenital univentricular AV connections, such as a double-inlet left ventricle.

  20. Physical Mechanisms and Scaling Laws of K-Shell Double Photoionization

    SciTech Connect

    Hoszowska, J.; Dousse, J.-Cl.; Berset, M.; Cao, W.; Fennane, K.; Kayser, Y.; Szlachetko, J.; Szlachetko, M.; Kheifets, A. K.; Bray, I.; Kavcic, M.

    2009-02-20

    We report on the photon energy dependence of the K-shell double photoionization (DPI) of Mg, Al, and Si. The DPI cross sections were derived from high-resolution measurements of x-ray spectra following the radiative decay of the K-shell double vacancy states. Our data evince the relative importance of the final-state electron-electron interaction to the DPI. By comparing the double-to-single K-shell photoionization cross-section ratios for neutral atoms with convergent close-coupling calculations for He-like ions, the effect of outer shell electrons on the K-shell DPI process is assessed. Universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms is revealed.

  1. Physical Mechanisms and Scaling Laws of K-Shell Double Photoionization

    NASA Astrophysics Data System (ADS)

    Hoszowska, J.; Kheifets, A. K.; Dousse, J.-Cl.; Berset, M.; Bray, I.; Cao, W.; Fennane, K.; Kayser, Y.; Kavčič, M.; Szlachetko, J.; Szlachetko, M.

    2009-02-01

    We report on the photon energy dependence of the K-shell double photoionization (DPI) of Mg, Al, and Si. The DPI cross sections were derived from high-resolution measurements of x-ray spectra following the radiative decay of the K-shell double vacancy states. Our data evince the relative importance of the final-state electron-electron interaction to the DPI. By comparing the double-to-single K-shell photoionization cross-section ratios for neutral atoms with convergent close-coupling calculations for He-like ions, the effect of outer shell electrons on the K-shell DPI process is assessed. Universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms is revealed.

  2. Doubles of Quasi-Quantum Groups

    NASA Astrophysics Data System (ADS)

    Hausser, Frank; Nill, Florian

    In [Dr1] Drinfeld showed that any finite dimensional Hopf algebra extends to a quasitriangular Hopf algebra , the quantum double of . Based on the construction of a so-called diagonal crossed product developed by the authors in [HN], we generalize this result to the case of quasi-Hopf algebras . As for ordinary Hopf algebras, as a vector space the ``quasi-quantum double'' is isomorphic to , where denotes the dual of . We give explicit formulas for the product, the coproduct, the R-matrix and the antipode on and prove that they fulfill Drinfeld's axioms of a quasitriangular quasi-Hopf algebra. In particular becomes an associative algebra containing as a quasi-Hopf subalgebra. On the other hand, is not a subalgebra of unless the coproduct on is strictly coassociative. It is shown that the category of finite dimensional representations of coincides with what has been called the double category of -modules by S. Majid [M2]. Thus our construction gives a concrete realization of Majid's definition of quasi-quantum doubles in terms of a Tannaka-Krein-like reconstruction procedure. The whole construction is shown to generalize to weak quasi-Hopf algebras with now being linearly isomorphic to a subspace of $.

  3. RAN and Double-Deficit Theory

    ERIC Educational Resources Information Center

    Cronin, Virginia S.

    2013-01-01

    Lervag and Hulme’s neuro-developmental theory and Wolf and Bowers’s double-deficit hypothesis were examined in this longitudinal study. A total of 130 children were tested in preschool and followed through fifth grade, when 84 remained in the study. During preschool and kindergarten the participants were given tests of end-sound discrimination…

  4. Propagating double layers in electronegative plasmas

    SciTech Connect

    Meige, A.; Plihon, N.; Hagelaar, G. J. M.; Boeuf, J.-P.; Chabert, P.; Boswell, R. W.

    2007-05-15

    Double layers have been observed to propagate from the source region to the diffusion chamber of a helicon-type reactor filled up with a low-pressure mixture of Ar/SF{sub 6} [N. Plihon et al., J. Appl. Phys. 98, 023306 (2005)]. In the present paper the most significant and new experimental results are reported. A fully self-consistent hybrid model in which the electron energy distribution function, the electron temperature, and the various source terms are calculated is developed to investigate these propagating double layers. The spontaneous formation of propagating double layers is only observed in the simulation for system in which the localized inductive heating is combined with small diameter chambers. The conditions of formation and the properties of the propagating double layers observed in the simulation are in good agreement with that of the experiment. By correlating the results of the experiment and the simulation, a formation mechanism compatible with ion two-stream instability is proposed.

  5. 46 CFR 171.105 - Double bottoms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (centimeters). L=LBP in feet (meters). (f) The line formed by the intersection of the margin plate and the.... EC01MR91.024 (g) A double bottom is not required in a tank that is integral with the hull of a vessel...

  6. 46 CFR 171.105 - Double bottoms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (centimeters). L=LBP in feet (meters). (f) The line formed by the intersection of the margin plate and the.... EC01MR91.024 (g) A double bottom is not required in a tank that is integral with the hull of a vessel...

  7. 46 CFR 171.105 - Double bottoms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (centimeters). L=LBP in feet (meters). (f) The line formed by the intersection of the margin plate and the.... EC01MR91.024 (g) A double bottom is not required in a tank that is integral with the hull of a vessel...

  8. [Clinical experience of automated double filtration plasmapheresis].

    PubMed

    Lee, C T; Chuang, F R; Hsu, K T; Lam, K K; Liao, S C; Liu, C C; Chen, J B; Jang, S W; Chien, Y S; Pan, H H

    1996-12-01

    Double filtration plasmapheresis, one kind of fractionation plasmapheresis, was developed from membrane type plasmapheresis to remove only the pathogen and return the normal protein back to the patient. We started our automated double filtration plasmapheresis since December 1993. There were 13 patients who received one hundred treatments totally during one year period. And they are myasthenia gravis (8 patients); acute inflammatory demyelinating polyneuropathy (1 patient), multiple myeloma (1 patient); acquired factor VIII inhibitor (1 patient); autoimmune hemolytic anemia (1 patient); systemic lupus erythematous (1 patient). Technically double filtration plasmapheresis is easy to perform and time-saving. It also makes necessity of replacement fluid less frequent. Incidence of complication is rare, and this includes hypotension 2%, palpitation 1%, headache 1%, hemolysis 4%, air emboli 1%, high secondary pressure 2%, and no motality during our treatment. Clinical response is documented in cases of myasthenia gravis; acute inflammatory demyelinating polyneuropathy and acquired factor VIII inhibitor in our study. In conclusion, double filtration plasmapheresis is a time-saving, convenient, and safe therapeutic modality with rare complication. Because its effectiveness on limited kinds of diseases and costs relatively high price, thus plasmapheresis should be used in selected cases and treat aggressively if indicated.

  9. Infrared properties of the Double Barrier Structure

    NASA Astrophysics Data System (ADS)

    Sheng, H. Y.; Sinkkonen, J.

    The infrared admittance of the Double Barrier Structure (DBS) is investigated by using a time-dependent quantum theory. The analysis is carried out under the small signal condition with no dc bias. The calculated results show conductance oscillations in the infrared frequency region. The oscillations are associated with the quantum well transit time resonances.

  10. How "Blind" Are Double-Blind Studies?

    ERIC Educational Resources Information Center

    Margraf, Jurgen; And Others

    1991-01-01

    Compared alprazolam, imipramine, and placebo in the treatment of panic disorder patients (n=59) to investigate concerns about the internal validity of the double-blind design. Found that the great majority of patients and physicians were able to rate accurately whether active drug or placebo had been given and physicians could distinguish between…

  11. Double tracks test site characterization report

    SciTech Connect

    1996-05-01

    This report presents the results of site characterization activities performed at the Double Tracks Test Site, located on Range 71 North, of the Nellis Air Force Range (NAFR) in southern Nevada. Site characterization activities included reviewing historical data from the Double Tracks experiment, previous site investigation efforts, and recent site characterization data. The most recent site characterization activities were conducted in support of an interim corrective action to remediate the Double Tracks Test Site to an acceptable risk to human health and the environment. Site characterization was performed using a phased approach. First, previously collected data and historical records sere compiled and reviewed. Generalized scopes of work were then prepared to fill known data gaps. Field activities were conducted and the collected data were then reviewed to determine whether data gaps were filled and whether other areas needed to be investigated. Additional field efforts were then conducted, as required, to adequately characterize the site. Characterization of the Double Tracks Test Site was conducted in accordance with the US Department of Energy`s (DOE) Streamlined Approach for Environmental Restoration (SAFER).

  12. Comment on 'Biphoton double-slit experiment'

    SciTech Connect

    Oriols, X.

    2005-01-01

    In a recent paper [Phys. Rev. A 68, 033803 (2003)] experimental results on a double-slit configuration with two entangled bosons are presented. The authors argue that their data contradicts the de Broglie-Bohm interpretation of quantum mechanics. In this Comment we show that this conclusion is incorrect.

  13. Double rf system for bunch shortening

    SciTech Connect

    Chin, Yong Ho.

    1990-11-01

    It was suggested by Zisman that the combination of the two systems (double rf system) may be more effective to shorten a bunch, compromising between the desirable and the undesirable effects mentioned above. In this paper, we demonstrate that a double rf system is, in fact, quite effective in optimizing the rf performance. The parameters used are explained, and some handy formulae for bunch parameters are derived. We consider an example of bunch shortening by adding a higher-harmonic rf system to the main rf system. The parameters of the main rf system are unchanged. The double rf system, however, can be used for another purpose. Namely, the original bunch length can be obtained with a main rf voltage substantially lower than for a single rf system without necessitating a high-power source for the higher-harmonic cavities. Using a double rf system, the momentum acceptance remains large enough for ample beam lifetime. Moreover, the increase in nonlinearity of the rf waveform increases the synchrotron tune spread, which potentially helps a beam to be stabilized against longitudinal coupled-bunch instabilities. We will show some examples of this application. We discuss the choice of the higher-harmonic frequency.

  14. Double beta decay: recent developments and projections

    SciTech Connect

    Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

    1983-08-01

    A report of recent events in both theoretical and experimental aspects of double beta decay is given. General theoretical considerations, recent developments in nuclear structure theory, geochronological determinations of half lives and ratios as well as laboratory experiments are discussed with emphasis on the past three years. Some projections are given. 28 references.

  15. An Investigation of Double Bass Vibrato Characteristics

    ERIC Educational Resources Information Center

    Mick, James

    2015-01-01

    The purpose of this study was to investigate and describe various vibrato characteristics of university double bass students. The primary objectives were: (1) to describe vibrato rate and width for commonly used fingers in first, fourth, and thumb positions; (2) to investigate whether students initiate vibrato in an upward or downward direction;…

  16. Double-wall tubing for oil recovery

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Carroll, W. F.; Jaffee, L. D.; Stimpson, L. D.

    1980-01-01

    Insulated double-wall tubing designed for steam injection oil recovery makes process more economical and allows deeper extension of wells. Higher quality wet steam is delivered through tubing to oil deposits with significant reductions in heat loss to surrounding rock allowing greater exploitation of previously unworkable reservoirs.

  17. Recursion Relations for Double Ramification Hierarchies

    NASA Astrophysics Data System (ADS)

    Buryak, Alexandr; Rossi, Paolo

    2016-03-01

    In this paper we study various properties of the double ramification hierarchy, an integrable hierarchy of hamiltonian PDEs introduced in Buryak (CommunMath Phys 336(3):1085-1107, 2015) using intersection theory of the double ramification cycle in the moduli space of stable curves. In particular, we prove a recursion formula that recovers the full hierarchy starting from just one of the Hamiltonians, the one associated to the first descendant of the unit of a cohomological field theory. Moreover, we introduce analogues of the topological recursion relations and the divisor equation both for the Hamiltonian densities and for the string solution of the double ramification hierarchy. This machinery is very efficient and we apply it to various computations for the trivial and Hodge cohomological field theories, and for the r -spin Witten's classes. Moreover, we prove the Miura equivalence between the double ramification hierarchy and the Dubrovin-Zhang hierarchy for the Gromov-Witten theory of the complex projective line (extended Toda hierarchy).

  18. Computing Determinants by Double-Crossing

    ERIC Educational Resources Information Center

    Leggett, Deanna; Perry, John; Torrence, Eve

    2011-01-01

    Dodgson's method of computing determinants is attractive, but fails if an interior entry of an intermediate matrix is zero. This paper reviews Dodgson's method and introduces a generalization, the double-crossing method, that provides a workaround for many interesting cases.

  19. From HHMI: Doubling Down on Diversity

    PubMed Central

    Asai, David J.; Bauerle, Cynthia

    2016-01-01

    In spite of modest gains in the past four decades, the United States has not been able to substantially improve on the pervasive underrepresentation of minorities in postsecondary science, technology, engineering, and mathematics (STEM) pathways. We suggest a way to guide a national effort to double the persistence of underrepresented minorities in STEM in the next decade. PMID:27587852

  20. Unintegrated double parton distributions - A summary

    NASA Astrophysics Data System (ADS)

    Golec-Biernat, Krzysztof; Staśto, Anna

    2017-03-01

    We present main elements of the construction of unintegrated double parton distribution functions which depend on transverse momenta of partons. We follow the method proposed by Kimber, Martin and Ryskin for a construction of unintegrated single parton distributions from the standard parton distribution functions.

  1. Oxygen isotope fractionation in double carbonates.

    PubMed

    Zheng, Yong-Fei; Böttcher, Michael E

    2016-01-01

    Oxygen isotope fractionations in double carbonates of different crystal structures were calculated by the increment method. Synthesis experiments were performed at 60 °C and 100 °C to determine oxygen and carbon isotope fractionations involving PbMg[CO3]2. The calculations suggest that the double carbonates of calcite structure are systematically enriched in (18)O relative to those of aragonite and mixture structures. Internally consistent oxygen isotope fractionation factors are obtained for these minerals with respect to quartz, calcite and water at a temperature range of 0-1200 °C. The calculated fractionation factors for double carbonate-water systems are generally consistent with the data available from laboratory experiments. The experimentally determined fractionation factors for PbMg[CO3]2, BaMg[CO3]2 and CaMg[CO3]2 against H2O not only fall between fractionation factors involving pure carbonate end-members but are also close to the calculated fractionation factors. In contrast, experimentally determined carbon isotope fractionation factors between PbMg[CO3]2 and CO2 are much closer to theoretical predictions for the cerussite-CO2 system than for the magnesite-CO2 system, similar to the fractionation behavior for BaMg[CO3]2. Therefore, the combined theoretical and experimental results provide insights into the effects of crystal structure and exchange kinetics on oxygen isotope partitioning in double carbonates.

  2. Double Tracks revegetation and monitoring plan

    SciTech Connect

    1997-07-01

    This document is a reclamation plan for short-term and long-term stabilization of land disturbed by activities associated with interim clean-up of radionuclide-contaminated surface soil at the Double Tracks site. This document has been prepared to provide general reclamation practices and procedures that will be followed during restoration of the cleanup site. Reclamation demonstration plots were established near the site in the fall of 1994 to evaluate the performance of several native species and to evaluate different irrigation strategies. Results of the study at Double Tracks, as well as the results from numerous studies conducted at other sites (Area 11 and Area 19 of the Nevada Test Site), have been summarized and incorporated into this final reclamation plan for the interim cleanup of the Double Tracks site, located northwest of the Nevada Test Site on the Nellis Air Force Range. Surface soils at Double Tracks were contaminated as a result of the detonation of a device containing plutonium and depleted uranium using chemical explosives. The total amount of Pu deposited on the site was between 980 and 1,600 grams and was scattered downwind south of the detonation site. Short-term stabilization consists of the application of a chemical soil stabilizer that is applied immediately following excavation of the contaminated soils to minimize Pu resuspension. Long-term stabilization is accomplished by the establishment of a permanent vegetation.

  3. Motion in an asymmetric double well

    NASA Astrophysics Data System (ADS)

    Brizard, Alain J.; Westland, Melissa C.

    2017-02-01

    The problem of the periodic motion of a particle in an asymmetric double-well (quartic) potential is solved explicitly in terms of the Weierstrass and Jacobi elliptic functions. While the solution of the orbital motion is expressed simply in terms of the Weierstrass elliptic function, the period of oscillation is more directly expressed in terms of periods of the Jacobi elliptic functions.

  4. Double Pomeron Exchange: the early years

    SciTech Connect

    Albrow, Michael G.

    2014-09-01

    I review the early experimental searches for double pomeron exchange, the first observations at the CERN Intersecting Storage Rings (ISR) and further studies at the SPS and Tevatron (fixed target). I only have space for a superficial coverage of some highlights, and will not cover later colliders with √s > GeV.

  5. Double pomeron exchange: The early years

    SciTech Connect

    Albrow, Michael G.

    2015-04-10

    I review the early experimental searches for double pomeron exchange, the first observations at the CERN Intersecting Storage Rings (ISR) and further studies at the SPS and Tevatron (fixed target). I only have space for a superficial coverage of some highlights, and will not cover later colliders with √(s)>100 GeV.

  6. Frequency doubled, cavity dumped feedback laser

    NASA Technical Reports Server (NTRS)

    Sipes, Jr., Donald L. (Inventor); Robinson, Deborah L. (Inventor)

    1989-01-01

    Higher efficiency in cavity dumping and frequency doubling in a laser used to produce modulated output beam pulses is achieved by deflecting light out of the resonant cavity to a third mirror through a frequency doubler using an electro-optic modulator and a polarizing beamsplitter in the resonant cavity, or using just an acousto-optic modulator to deflect light out of the laser cavity in response to a control signal (electric or acoustic). The frequency doubler in front of the third mirror rotates the frequency doubled light so that it will pass out of the laser cavity through the polarizing beamsplitter, while undoubled frequency light is reflected by the polarizing beamsplitter back into the gain medium of the laser. In the case of using a type-II frequency doubler, a dichroic beamsplitter deflects out the frequency doubled light and passes the undoubled frequency light to the polarizing beamsplitter for return to the laser gain medium. If an acousto-optic modulator is used, it deflects light out of the primary laser cavity, so a polarizing beamsplitter is not needed, and only a dichroic beamsplitter is needed to separate frequency doubled light out of the path from the third mirror.

  7. From HHMI: Doubling Down on Diversity

    ERIC Educational Resources Information Center

    Asai, David J.; Bauerle, Cynthia

    2016-01-01

    In spite of modest gains in the past four decades, the United States has not been able to substantially improve on the pervasive underrepresentation of minorities in postsecondary science, technology, engineering, and mathematics (STEM) pathways. We suggest a way to guide a national effort to double the persistence of underrepresented minorities…

  8. 49 CFR 380.203 - LCV Doubles.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS SPECIAL TRAINING REQUIREMENTS LCV Driver-Training Program § 380.203 LCV Doubles. (a) To qualify for the training necessary...

  9. Double Shell Tank (DST) Utilities Specification

    SciTech Connect

    GRAVES, C.E.

    2001-01-18

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied to the Double-Shell Tank (DST) Utilities (electrical, raw water, potable water, service air and instrument air), which supports the first phase of Waste Feed Delivery.

  10. Physical Properties of the Double Kerr Solution

    NASA Astrophysics Data System (ADS)

    Herdeiro, Carlos A. R.; Rebelo, Carmen

    We consider two special cases, dubbed counter-rotating and co-rotating of the double-Kerr solution, in four spacetime dimensions. We discuss how various physical properties of the black holes vary as the distance between them varies, namely: the horizon angular velocity and extremality condition, the horizon and ergo-surface geometry.

  11. Epitaxial Halide Perovskite Lateral Double Heterostructure.

    PubMed

    Wang, Yiping; Chen, Zhizhong; Deschler, Felix; Sun, Xin; Lu, Toh-Ming; Wertz, Esther A; Hu, Jia-Mian; Shi, Jian

    2017-03-28

    Epitaxial III-V semiconductor heterostructures are key components in modern microelectronics, electro-optics, and optoelectronics. With superior semiconducting properties, halide perovskite materials are rising as promising candidates for coherent heterostructure devices. In this report, spinodal decomposition is proposed and experimentally implemented to produce epitaxial double heterostructures in halide perovskite system. Pristine epitaxial mixed halide perovskites rods and films were synthesized via van der Waals epitaxy by chemical vapor deposition method. At room temperature, photon was applied as a knob to regulate the kinetics of spinodal decomposition and classic coarsening. By this approach, halide perovskite double heterostructures were created carrying epitaxial interfaces and outstanding optical properties. Reduced Fröhlich electron-phonon coupling was discovered in coherent halide double heterostructure, which is hypothetically attributed to the classic phonon confinement effect widely existing in III-V double heterostructures. As a proof-of-concept, our results suggest that halide perovskite-based epitaxial heterostructures may be promising for high-performance and low-cost optoelectronics, electro-optics, and microelectronics. Thus, ultimately, for practical device applications, it may be worthy to pursue these heterostructures via conventional vapor phase epitaxy approaches widely practised in III-V field.

  12. Pion double charge exchange and hadron dynamics

    SciTech Connect

    Johnson, M.B.

    1991-01-01

    This paper will review theoretical results to show how pion double charge exchange is contributing to our understanding of hadron dynamics in nuclei. The exploitation of the nucleus as a filter is shown to be essential in facilitating the comparison between theory and experiment. 23 refs., 3 figs., 2 tabs.

  13. Wide Band to ''Double Band'' upgrade

    SciTech Connect

    Kasper, P.; Currier, R.; Garbincius, P.; Butler, J.

    1988-06-01

    The Wide Band beam currently uses electrons obtained from secondary photon conversions to produce the photon beam incident on the experimental targets. By transporting the positrons produced in these conversions as well as the electrons it is possible to almost double the number of photons delivered to the experiments per primary beam proton. 11 figs.

  14. The Double Bind: The next Generation

    ERIC Educational Resources Information Center

    Malcom, Lindsey E.; Malcom, Shirley M.

    2011-01-01

    In this foreword, Shirley Malcom and Lindsey Malcom speak to the history and current status of women of color in science, technology, engineering, and mathematics (STEM) fields. As the author of the seminal report "The Double Bind: The Price of Being a Minority Woman in Science", Shirley Malcom is uniquely poised to give us an insightful…

  15. [Euthanasia and the doctrine of double effect].

    PubMed

    Klein, Martin

    2005-01-01

    Direct active euthanasia is prohibited in most countries while passive and indirect is not. However, many arguments against the legalization of voluntary active euthanasia are flawed. Ethical differences between active and passive or indirect euthanasia are difficult to maintain especially when the passivity of the actor causes death. The crucial point is not activity or passivity but respect for the autonomy of individual human beings. In particular there appears to be little ethical difference between active and indirect euthanasia. Indirect euthanasia has often been justified by the principle of double effect, which traces back to Thomas Aquinas. But resorting to this rule contains a logical fallacy. The principle of double effect does not allow foreseen and unwanted adverse effects of an action to occur when they are avoidable. In terminal sedation, an example for indirect euthanasia, hypoxemia and dehydration can easily be prevented by respirator therapy and fluid administration. Therefore the rule of double effect is not applicable. Indirect and direct active euthanasia cannot be ethically distinguished by resorting to the principle of double effect.

  16. Double-shell tank emergency pumping guide

    SciTech Connect

    BROWN, M.H.

    1999-02-24

    This Double-Shell Tank Emergency Pumping Guide provides the preplanning necessary to expeditiously remove any waste that may leak from the primary tank to the secondary tank for Hanford's 28 DSTS. The strategy is described, applicable emergency procedures are referenced, and transfer routes and pumping equipment for each tank are identified.

  17. Biological evaluation of layered double hydroxides as efficient drug vehicles.

    PubMed

    Li, Yan; Liu, Dan; Ai, Hanhua; Chang, Qing; Liu, Dandan; Xia, Ying; Liu, Shuwen; Peng, Nanfang; Xi, Zhuge; Yang, Xu

    2010-03-12

    Recently there has been a rapid expansion of the development of bioinorganic hybrid systems for safe drug delivery. Layered double hydroxides (LDH), a variety of available inorganic matrix, possess great promise for this purpose. In this study, an oxidative stress biomarker system, including measurement of reactive oxygen species, glutathione content, endogenous nitric oxide, carbonyl content in proteins, DNA strand breaks and DNA-protein crosslinks, was designed to evaluate the biocompatibility of different concentrations of nano-Zn/Al-LDH with a Hela cell line. The drug delivery activity of the LDH-folic-acid complex was also assessed. The resulting data clearly demonstrated that nano-LDH could be applied as a relatively safe drug vehicle with good delivery activity, but with the caveat that the effects of high dosages observed here should not be ignored when attempting to maximize therapeutic activity by increasing LDH concentration.

  18. Assessing the Assessment Center.

    ERIC Educational Resources Information Center

    LaRue, James

    1989-01-01

    Describes the historical use of assessment centers as staff development and promotional tools and their current use in personnel selection. The elements that constitute a true assessment center are outlined, and a discussion of the advantages and disadvantages for employers and applicants focuses on positions in library administration. (10…

  19. Assessing Classroom Assessment Techniques

    ERIC Educational Resources Information Center

    Simpson-Beck, Victoria

    2011-01-01

    Classroom assessment techniques (CATs) are teaching strategies that provide formative assessments of student learning. It has been argued that the use of CATs enhances and improves student learning. Although the various types of CATs have been extensively documented and qualitatively studied, there appears to be little quantitative research…

  20. Characterization of circulating CD4(+) CD8(+) double positive and CD4(-) CD8(-) double negative T-lymphocyte in children with β-thalassemia major.

    PubMed

    Zahran, Asmaa M; Saad, Khaled; Elsayh, Khalid I; Alblihed, Mohamd A

    2017-03-01

    Infectious complications represent the second most common cause of mortality and a major cause of morbidity in β-thalassemia major (BTM), with a prevalence of 12-13%. The data on unconventional T-lymphocyte subsets in BTM children are limited. The aim of the present study was to investigate and evaluate phenotypic alterations in CD4(+)CD8(+) double positive (DP), CD4(-) CD8(-) double negative (DN), and natural killer T-lymphocytes (NKT) in BTM children in comparison to healthy controls. Our case control study included 80 children with BTM and 40 healthy children as controls. Assessment of unconventional T-lymphocyte populations was done using sensitive four-color flow cytometry (FACSCalibur). Our analysis of the data showed a significantly higher frequency CD4(+) CD8(+) (double-positive) T cells, CD4(-) CD8(-) (double negative) T cells, and natural killer T cells in the peripheral blood of both BTM groups (splenectomized and non-splenectomized) as compared to healthy controls, suggesting that these cells may play a role in the clinical course of BTM. The relationship of the unconventional T-lymphocytes to immune disorders in BTM children remains to be determined. Further longitudinal study with a larger sample size is warranted to elucidate the role these cells in BTM.

  1. Evaluation of retention of pit and fissure sealants placed with and without air abrasion pretreatment in 6-8 year old children – An in vivo study

    PubMed Central

    Goswami, Mridula

    2017-01-01

    Background The success of pit and fissure sealants is directly related to their retention. The purpose of this study was to assess and compare the retention of pit and fissure sealants placed using acid etch alone and a combination of air abrasion and acid etch techniques. Material and Methods 50 subjects aged 6-8 years were included in the study. Primary second molars and permanent first molars were sealed in all four quadrants using split mouth design. The right maxillary and mandibular molars (Group A) were treated by acid etching alone while the left maxillary and mandibular molars (Group B) were pretreated with air abrasion followed by acid etching before application of pit and fissure sealant. Retention of sealants was checked using Simonsen’s criteria of sealant retention after three and six months of sealant application. Results There was no significant difference in retention of sealants in Group A and Group B (p<0.05) after three and six months follow up. The difference in sealant retention in primary and permanent molars was not significant (p>0.05). Maxillary molars showed superior retention compared to mandibular molars, which was statistically significant at both three and six months (p<0.05). Conclusions Combining air abrasion pretreatment with subsequent acid etching did not result in statistically significant difference in sealant retention compared to acid etching alone in both primary and permanent molars after 3 and 6 months follow up. An additional air abrasion pretreatment step can be avoided in pediatric patients when placing sealants and the procedure can be completed faster with better behavior management using acid etching alone. Key words:Pit and fissure sealant, acid etching, air abrasion. PMID:28210438

  2. Delivery of double singleton pregnancies in a woman with a double uterus, double cervix, and complete septate vagina.

    PubMed

    Yang, Ming-Jie; Tseng, Jen-Yu; Chen, Chih-Yao; Li, Hsin-Yang

    2015-12-01

    Uterine anomalies involving a double uterus, double cervix, also known as didelphys uterus, and complete septate vagina are rarely seen and have an associated fertility problem. However, artificial reproductive technology with embryo transfers can help solve this fertility challenge. Conception in the uterus in just one side is commonly seen for embryos, which are always transferred through the usually used (dilated) vagina. We here present a patient with the above uterine anomaly who conceived with the aid of in vitro fertilization and embryo transfer to both uterine cavities under general anesthesia, which resulted in successful double singleton pregnancies with one fetus in each uterus. With intensive prenatal care, the pregnancy course for each fetus was rather uneventful. Although both fetuses were in cephalic presentation, cesarean section was performed at the 39(th) week of gestation with good outcomes in order to preclude anticipated difficulties if the baby had been delivered through the rarely dilated vagina. However, order of birth between the two fetuses was a crucial decision during the operation.

  3. The Double-Deficit Hypothesis in Spanish Developmental Dyslexia

    ERIC Educational Resources Information Center

    Jimenez, Juan E.; Hernandez-Valle, Isabel; Rodriguez, Cristina; Guzman, Remedios; Diaz, Alicia; Ortiz, Rosario

    2008-01-01

    The double-deficit hypothesis (DDH) of developmental dyslexia was investigated in seven to twelve year old Spanish children. It was observed that the double deficit (DD) group had the greatest difficulty with reading.

  4. Double photoionization of helium with synchrotron x-rays: Proceedings

    SciTech Connect

    Not Available

    1994-01-01

    This report contains papers on the following topics: Overview and comparison of photoionization with charged particle impact; The ratio of double to single ionization of helium: the relationship of photon and bare charged particle impact ionization; Double photoionization of helium at high energies; Compton scattering of photons from electrons bound in light elements; Electron ionization and the Compton effect in double ionization of helium; Elimination of two atomic electrons by a single energy photon; Double photoionization of helium at intermediate energies; Double Photoionization: Gauge Dependence, Coulomb Explosion; Single and Double Ionization by high energy photon impact; The effect of Compton Scattering on the double to single ionization ratio in helium; and Double ionization of He by photoionization and Compton scattering. These papers have been cataloged separately for the database.

  5. Progress Towards Doubling the Beam Power at Fermilab's Accelerator Complex

    SciTech Connect

    Kourbanis, ioanis

    2014-06-01

    After a 14 month shutdown accelerator modifications and upgrades are in place to allow us doubling of the Main Injector beam power. We will discuss the past MI high power operation and the current progress towards doubling the power.

  6. Double Mine Building, general view in setting; view northeast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Double Mine Building, general view in setting; view northeast - Fort McKinley, Double Mine Building, East side of East Side Drive, approximately 125 feet south of Weymouth Way, Great Diamond Island, Portland, Cumberland County, ME

  7. 26 CFR 509.120 - Double taxation claims.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... CONVENTIONS SWITZERLAND General Income Tax § 509.120 Double taxation claims. (a) General. Under Article XVII... United States or Switzerland has resulted, or will result, in double taxation contrary to the...

  8. Boltzmann equation with double-well potentials

    NASA Astrophysics Data System (ADS)

    Chiacchiera, Silvia; Macrı, Tommaso; Trombettoni, Andrea

    2016-10-01

    We study the dynamics of an interacting classical gas trapped in a double-well potential at finite temperature. Two model potentials are considered: a cubic box with a square barrier in the middle, and a harmonic trap with a Gaussian barrier along one direction. The study is performed using the Boltzmann equation, solved numerically via the test-particle method. We introduce and discuss a simple analytical model that allows one to provide estimates of the relaxation time, which are compared with numerical results. Finally, we use our findings to make numerical and analytical predictions for the case of a fermionic mixture in the normal-fluid phase in a realistic double-well potential relevant for experiments with cold atoms.

  9. Unwinding and rewinding: double faces of helicase?

    PubMed

    Wu, Yuliang

    2012-01-01

    Helicases are enzymes that use ATP-driven motor force to unwind double-stranded DNA or RNA. Recently, increasing evidence demonstrates that some helicases also possess rewinding activity-in other words, they can anneal two complementary single-stranded nucleic acids. All five members of the human RecQ helicase family, helicase PIF1, mitochondrial helicase TWINKLE, and helicase/nuclease Dna2 have been shown to possess strand-annealing activity. Moreover, two recently identified helicases-HARP and AH2 have only ATP-dependent rewinding activity. These findings not only enhance our understanding of helicase enzymes but also establish the presence of a new type of protein: annealing helicases. This paper discusses what is known about these helicases, focusing on their biochemical activity to zip and unzip double-stranded DNA and/or RNA, their possible regulation mechanisms, and biological functions.

  10. Double-slit experiment in momentum space

    NASA Astrophysics Data System (ADS)

    Ivanov, I. P.; Seipt, D.; Surzhykov, A.; Fritzsche, S.

    2016-08-01

    Young's classic double-slit experiment demonstrates the reality of interference when waves and particles travel simultaneously along two different spatial paths. Here, we propose a double-slit experiment in momentum space, realized in the free-space elastic scattering of vortex electrons. We show that this process proceeds along two paths in momentum space, which are well localized and well separated from each other. For such vortex beams, the (plane-wave) amplitudes along the two paths acquire adjustable phase shifts and produce interference fringes in the final angular distribution. We argue that this experiment can be realized with the present-day technology. We show that it gives experimental access to the Coulomb phase, a quantity which plays an important role in all charged particle scattering but which usual scattering experiments are insensitive to.

  11. Electron-impact double ionization of magnesium

    SciTech Connect

    Ford, M.J.; El-Marji, B.; Doering, J.P.; Moore, J.H.; Coplan, M.A.; Cooper, J.W.

    1998-01-01

    Electron-impact double-ionization cross sections differential in the angles of the two ejected electrons have been measured at impact energies of 422 and 1052 eV. The energies of the ejected electrons were fixed at 100 eV each. The cross sections are very different at the two incident energies. At 1052 eV the ejected electrons are preferentially found in the forward direction with respect to the incident beam. At 422 eV they are found in the forward and backward directions with approximately equal probability. The 422-eV cross sections are largest when the incident-electron and ejected-electron momentum vectors lie in a common plane. The observations are discussed in the context of several models for double ionization. {copyright} {ital 1998} {ital The American Physical Society}

  12. Reversible Heating in Electric Double Layer Capacitors

    NASA Astrophysics Data System (ADS)

    Janssen, Mathijs; van Roij, René

    2017-03-01

    A detailed comparison is made between different viewpoints on reversible heating in electric double layer capacitors. We show in the limit of slow charging that a combined Poisson-Nernst-Planck and heat equation, first studied by d'Entremont and Pilon [J. Power Sources 246, 887 (2014), 10.1016/j.jpowsour.2013.08.024], recovers the temperature changes as predicted by the thermodynamic identity of Janssen et al. [Phys. Rev. Lett. 113, 268501 (2014), 10.1103/PhysRevLett.113.268501], and disagrees with the approximative model of Schiffer et al. [J. Power Sources 160, 765 (2006), 10.1016/j.jpowsour.2005.12.070] that predominates the literature. The thermal response to the adiabatic charging of supercapacitors contains information on electric double layer formation that has remained largely unexplored.

  13. Machine learning bandgaps of double perovskites

    NASA Astrophysics Data System (ADS)

    Pilania, G.; Mannodi-Kanakkithodi, A.; Uberuaga, B. P.; Ramprasad, R.; Gubernatis, J. E.; Lookman, T.

    2016-01-01

    The ability to make rapid and accurate predictions on bandgaps of double perovskites is of much practical interest for a range of applications. While quantum mechanical computations for high-fidelity bandgaps are enormously computation-time intensive and thus impractical in high throughput studies, informatics-based statistical learning approaches can be a promising alternative. Here we demonstrate a systematic feature-engineering approach and a robust learning framework for efficient and accurate predictions of electronic bandgaps of double perovskites. After evaluating a set of more than 1.2 million features, we identify lowest occupied Kohn-Sham levels and elemental electronegativities of the constituent atomic species as the most crucial and relevant predictors. The developed models are validated and tested using the best practices of data science and further analyzed to rationalize their prediction performance.

  14. Machine learning bandgaps of double perovskites.

    PubMed

    Pilania, G; Mannodi-Kanakkithodi, A; Uberuaga, B P; Ramprasad, R; Gubernatis, J E; Lookman, T

    2016-01-19

    The ability to make rapid and accurate predictions on bandgaps of double perovskites is of much practical interest for a range of applications. While quantum mechanical computations for high-fidelity bandgaps are enormously computation-time intensive and thus impractical in high throughput studies, informatics-based statistical learning approaches can be a promising alternative. Here we demonstrate a systematic feature-engineering approach and a robust learning framework for efficient and accurate predictions of electronic bandgaps of double perovskites. After evaluating a set of more than 1.2 million features, we identify lowest occupied Kohn-Sham levels and elemental electronegativities of the constituent atomic species as the most crucial and relevant predictors. The developed models are validated and tested using the best practices of data science and further analyzed to rationalize their prediction performance.

  15. Machine learning bandgaps of double perovskites

    PubMed Central

    Pilania, G.; Mannodi-Kanakkithodi, A.; Uberuaga, B. P.; Ramprasad, R.; Gubernatis, J. E.; Lookman, T.

    2016-01-01

    The ability to make rapid and accurate predictions on bandgaps of double perovskites is of much practical interest for a range of applications. While quantum mechanical computations for high-fidelity bandgaps are enormously computation-time intensive and thus impractical in high throughput studies, informatics-based statistical learning approaches can be a promising alternative. Here we demonstrate a systematic feature-engineering approach and a robust learning framework for efficient and accurate predictions of electronic bandgaps of double perovskites. After evaluating a set of more than 1.2 million features, we identify lowest occupied Kohn-Sham levels and elemental electronegativities of the constituent atomic species as the most crucial and relevant predictors. The developed models are validated and tested using the best practices of data science and further analyzed to rationalize their prediction performance. PMID:26783247

  16. Double pulse Thomson scattering system at RTP

    SciTech Connect

    Beurskens, M.N.; Barth, C.J.; Chu, C.C.; Donne, A.J.; Herranz, J.A.; Lopes Cardozo, N.J.; van der Meiden, H.J.; Pijper, F.J.

    1997-01-01

    In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10{endash}800 {mu}s, max. 2{times}12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV{endash}7 keV can be determined with an accuracy as good as 2{percent}{endash}3{percent} for electron densities of 10{sup 20} m{sup {minus}3}, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. {copyright} {ital 1997 American Institute of Physics.}

  17. Recombination energy in double white dwarf formation

    NASA Astrophysics Data System (ADS)

    Nandez, J. L. A.; Ivanova, N.; Lombardi, J. C.

    2015-06-01

    In this Letter, we investigate the role of recombination energy during a common envelope event. We confirm that taking this energy into account helps to avoid the formation of the circumbinary envelope commonly found in previous studies. For the first time, we can model a complete common envelope event, with a clean compact double white dwarf binary system formed at the end. The resulting binary orbit is almost perfectly circular. In addition to considering recombination energy, we also show that between 1/4 and 1/2 of the released orbital energy is taken away by the ejected material. We apply this new method to the case of the double white dwarf system WD 1101+364, and we find that the progenitor system at the start of the common envelope event consisted of an ˜1.5 M⊙ red giant star in an ˜30 d orbit with a white dwarf companion.

  18. Tidal Effects in Inspiraling Double White Dwarfs

    NASA Astrophysics Data System (ADS)

    Willems, B.; Kalogera, Vicky; Vecchio, A.; Ivanova, N.; Deloye, C.; Hansen, B.

    2006-12-01

    Despite the overwhelming abundance of double white dwarfs in the LISA gravitational wave frequency band, modeling of their waveforms has remained limited to the point-mass approximation in which gravitational radiation is the only source of systemic orbital angular momentum loss. As a significant fraction of these systems spirals in to periods as short as 5-10 minutes, tidal effects can, however, play an important role in modifying the gravitational wave frequency evolution. The strength of the tidal effects depends strongly on the energy dissipation mechanism damping the tides, which, for white dwarfs, is highly uncertain. In this poster, we present the first results of a systematic study of tidal dissipation in white dwarfs, and the impact of tides on the gravitational wave signal of close double white dwarfs.

  19. Double complexes and local cochain projections

    PubMed Central

    Falk, Richard S; Winther, Ragnar

    2015-01-01

    The construction of projection operators, which commute with the exterior derivative and at the same time are bounded in the proper Sobolev spaces, represents a key tool in the recent stability analysis of finite element exterior calculus. These so-called bounded cochain projections have been constructed by combining a smoothing operator and the unbounded canonical projections defined by the degrees of freedom. However, an undesired property of these bounded projections is that, in contrast to the canonical projections, they are nonlocal. The purpose of this article is to discuss a recent alternative construction of bounded cochain projections, which also are local. A key tool for the new construction is the structure of a double complex, resembling the Čech-de Rham double complex of algebraic topology. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 541–551, 2015 PMID:25914441

  20. Observations of double discontinuities in the magnetotail

    NASA Astrophysics Data System (ADS)

    Whang, Y. C.; Fairfield, D.; Smith, E. J.; Lepping, R. P.; Kokubun, S.; Saito, Y.

    Observations of slow shocks in the Earth's magnetotail at the plasma sheet-lobe boundaries have been well documented. We restudy the magnetic field data of two slow shocks: one was observed from Geotail on January 17, 1994 at XGSE = -92 RE, and another was observed from ISEE-3 on February 2, 1983 at XGSE = -220 RE. In both cases, the slow shock layer was followed by an adjoining rotational discontinuity layer on the postshock side. Compound structures each composed of a slow shock layer and an adjoining rotational discontinuity layer have been recently observed in interplanetary space from Wind, Geotail and Imp-8. Because the two successive discontinuities are very close to each other, the compound structure looks like a new kind of MHD discontinuity. It may be called a double discontinuity. Since double discontinuities exist not only in interplanetary space but also in the magnetotail region, they could be a general MHD structure in space plasma.

  1. Double-line spectroscopic orbit for Capella

    SciTech Connect

    Shen, L.-Z.; Beavers, W.I.; Eitter, J.J.; Salzer, J.J.

    1985-08-01

    Radial-velocity spectrometer measurements of both components of the double-line Capella system have been combined with earlier radial-velocity measurements from four previous studies to produce an improved double-line orbit. The resulting mass ratio M1/M2 = 1.18 + or - 0.02 differs by only 2 percent from the virtually ignored previous determination by Struve (1939). Combining the new radial-velocity elements with McAlister's (1981) recent interferometric orbit allows the determination of the individual masses of M1 = 3.31 + or 0.08 solar mass and M2 = 2.80 + or - 0.05 solar mass. This mass difference is perhaps too great for both stars to be on the first crossing of the Hertzsprung gap as proposed by Boesgaard (1971). 38 references.

  2. Machine learning bandgaps of double perovskites

    SciTech Connect

    Pilania, G.; Mannodi-Kanakkithodi, A.; Uberuaga, B. P.; Ramprasad, R.; Gubernatis, J. E.; Lookman, T.

    2016-01-19

    The ability to make rapid and accurate predictions on bandgaps of double perovskites is of much practical interest for a range of applications. While quantum mechanical computations for high-fidelity bandgaps are enormously computation-time intensive and thus impractical in high throughput studies, informatics-based statistical learning approaches can be a promising alternative. Here we demonstrate a systematic feature-engineering approach and a robust learning framework for efficient and accurate predictions of electronic bandgaps of double perovskites. After evaluating a set of more than 1.2 million features, we identify lowest occupied Kohn-Sham levels and elemental electronegativities of the constituent atomic species as the most crucial and relevant predictors. As a result, the developed models are validated and tested using the best practices of data science and further analyzed to rationalize their prediction performance.

  3. Machine learning bandgaps of double perovskites

    DOE PAGES

    Pilania, G.; Mannodi-Kanakkithodi, A.; Uberuaga, B. P.; ...

    2016-01-19

    The ability to make rapid and accurate predictions on bandgaps of double perovskites is of much practical interest for a range of applications. While quantum mechanical computations for high-fidelity bandgaps are enormously computation-time intensive and thus impractical in high throughput studies, informatics-based statistical learning approaches can be a promising alternative. Here we demonstrate a systematic feature-engineering approach and a robust learning framework for efficient and accurate predictions of electronic bandgaps of double perovskites. After evaluating a set of more than 1.2 million features, we identify lowest occupied Kohn-Sham levels and elemental electronegativities of the constituent atomic species as the mostmore » crucial and relevant predictors. As a result, the developed models are validated and tested using the best practices of data science and further analyzed to rationalize their prediction performance.« less

  4. Double layer capacitance of carbon foam electrodes

    SciTech Connect

    Delnick, F.M.; Ingersoll, D.; Firsich, D.

    1993-11-01

    We have evaluated a wide variety of microcellular carbon foams prepared by the controlled pyrolysis and carbonization of several polymers including: polyacrylonitrile (PAN), polymethacrylonitrile (PMAN), resorcinol/formaldehyde (RF), divinylbenzene/methacrylonitrile (DVB), phenolics (furfuryl/alcohol), and cellulose polymers such as Rayon. The porosity may be established by several processes including: Gelation (1-5), phase separation (1-3,5-8), emulsion (1,9,10), aerogel/xerogel formation (1,11,12,13), replication (14) and activation. In this report we present the complex impedance analysis and double layer charging characteristics of electrodes prepared from one of these materials for double layer capacitor applications, namely activated cellulose derived microcellular carbon foam.

  5. Double layer capacitance of carbon foam electrodes

    NASA Astrophysics Data System (ADS)

    Delnick, F. M.; Ingersoll, D.; Firsich, D.

    We have evaluated a wide variety of microcellular carbon foams prepared by the controlled pyrolysis and carbonization of several polymers including: polyacrylonitrile (PAN), polymethacrylonitrile (PMAN), resorcinol/formaldehyde (RF), divinylbenzene/methacrylonitrile (DVB), phenolics (furfuryl/alcohol), and cellulose polymers such as Rayon. The porosity may be established by several processes including: gelation (1-5), phase separation (1-3,5-8), emulsion (1,9,10), aerogel/xerogel formation (1,11,12,13), replication (14), and activation. In this report we present the complex impedance analysis and double layer charging characteristics of electrodes prepared from one of these materials for double layer capacitor applications, namely activated cellulose derived microcellular carbon foam.

  6. Single incision laparoscopic splenectomy with double port.

    PubMed

    Vatansev, Celalettin; Ece, Ilhan

    2009-12-01

    In response to the increasing interest in minimally invasive surgery by both patients and surgeons, most abdominal surgery today is carried out laparoscopically. Laparoscopic splenectomy has become a gold standard in the treatment of spleen disorders related to hematologic diseases. Increasing laparoscopic surgery experience and improved new vessel sealing equipment have led to a decreasing number of ports in laparoscopic surgery and to operations from 1 incision. We carried out single-incision double-port laparoscopic splenectomy in a patient with immune thrombocytopenic purpura using only 2 trocars with a simple manipulation. Our review of the related literature revealed no earlier description of a single-incision double-port laparoscopic splenectomy. We therefore present herein this earlier unreported technique.

  7. Double layers acting as particles accelerators

    SciTech Connect

    Sanduloviciu, M.; Lozneanu, E.

    1995-12-31

    It is shown that self-consistent stable and unstable double layers generated in plasma after a self-organisation process are able to accelerate charged particles. The implication of cosmic double layers (Dls) in the acceleration of electrical charged particles long been advocated by Alfven and his Stockholm school is today disputed by argument that static electric fields associated with Dls are conservative and consequently the line integral of the electric field outside the DL balances the line integral inside it. Related with this dispute we will evidence some, so far not considered, facts which are in our opinion arguments that aurora Dls are able to energize particles. For justifying this assertion we start from recent experimental results concerning the phenomenology of self-consistent Dls whose generation involve beside ionisations the neutrals excitations which are at tile origin of the light phenomena as those observed in auroras.

  8. CCD Measurements of Visual Double Stars

    NASA Astrophysics Data System (ADS)

    Buchheim, Robert K.

    2008-05-01

    The CCD-imaging equipment that many amateur astronomers use for astrophotography and photometry can also be used to measure the separation, position angle, and magnitude difference of visual double stars. There are a few imaging and data analysis procedures that are unique to this project. I describe a simple PSF-model that provides good accuracy and repeatability in measurements of pairs which -- due to their close spacing and/or large magnitude difference -- would be beyond the reach of standard astrometric software. This project has some conceptual similarities to asteroid lightcurve determination: in both cases, we are presented with a huge number of potential targets that need observation; repeated observation at different epochs adds value to the initial observations; there are very few professional astronomers pursuing these studies; and there exists a Journal devoted to publication of these observations so that they will be available to the professional community. Hence, double star measurement may be a fruitful area for amateur contributions.

  9. Large Amplitude Oscillations of a Double Pendulum

    NASA Astrophysics Data System (ADS)

    Gerres, Jeffrey M.; Jacobs, Robert M.; Kasun, Sara F.; Bacon, Margaret E.; Nagolu, Chakravarthi M.; Owens, Erin L.; Siehl, Kevin F.; Thomsen, Marshall; Troyer, Jon S.

    2008-03-01

    The nature of the normal modes of oscillation in the small angle regime of a double pendulum is well established. However, for large amplitude oscillations, a closed form solution of the differential equations of motion does not exist. Using Lagrange formalism, we explore both the in-phase and out-of-phase normal modes of oscillation of a double pendulum as a function of the mass ratio of the two bobs and their initial angular positions. We conduct the analysis using MatLab, where we initially verify our code in the known small amplitude limit. Among our results we find that certain symmetries between the in-phase and out-of-phase normal modes that exist in the small amplitude limit are no longer present at large amplitudes.

  10. Reversible Heating in Electric Double Layer Capacitors.

    PubMed

    Janssen, Mathijs; van Roij, René

    2017-03-03

    A detailed comparison is made between different viewpoints on reversible heating in electric double layer capacitors. We show in the limit of slow charging that a combined Poisson-Nernst-Planck and heat equation, first studied by d'Entremont and Pilon [J. Power Sources 246, 887 (2014)JPSODZ0378-775310.1016/j.jpowsour.2013.08.024], recovers the temperature changes as predicted by the thermodynamic identity of Janssen et al. [Phys. Rev. Lett. 113, 268501 (2014)PRLTAO0031-900710.1103/PhysRevLett.113.268501], and disagrees with the approximative model of Schiffer et al. [J. Power Sources 160, 765 (2006)JPSODZ0378-775310.1016/j.jpowsour.2005.12.070] that predominates the literature. The thermal response to the adiabatic charging of supercapacitors contains information on electric double layer formation that has remained largely unexplored.

  11. Monitoring of Double Stud Wall Moisture Conditions in the Northeast

    SciTech Connect

    Ueno, K.

    2015-03-01

    Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double stud walls have a higher risk of interior-sourced condensation moisture damage, when compared with high-R approaches using exterior insulating sheathing.; Moisture conditions in double stud walls were monitored in Zone 5A (Massachusetts); three double stud assemblies were compared.

  12. Double-clad nuclear fuel safety rod

    DOEpatents

    McCarthy, William H.; Atcheson, Donald B.; Vaidyanathan, Swaminathan

    1984-01-01

    A device for shutting down a nuclear reactor during an undercooling or overpower event, whether or not the reactor's scram system operates properly. This is accomplished by double-clad fuel safety rods positioned at various locations throughout the reactor core, wherein melting of a secondary internal cladding of the rod allows the fuel column therein to shift from the reactor core to place the reactor in a subcritical condition.

  13. Double dumb-bell calculus in childhood.

    PubMed

    Joshi, Prashant; Sarda, Dinesh; Ahmad, Ashraf; Kothari, Paras

    2009-01-01

    An eight-year old male was admitted with complaints of right scrotal swelling, dysuria and intermittent retention of urine for 10 days. On per-rectal examination, a hard mass was palpable in the posterior urethra. An X-ray (KUB) of the abdomen revealed a double dumb-bell calculus at the base of bladder, extending into the posterior urethra. A cystolithotomy via the suprapubic approach was successfully curative.

  14. Doubling Time for Nonexponential Families of Functions

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.

    2010-01-01

    One special characteristic of any exponential growth or decay function f(t) = Ab[superscript t] is its unique doubling time or half-life, each of which depends only on the base "b". The half-life is used to characterize the rate of decay of any radioactive substance or the rate at which the level of a medication in the bloodstream decays as it is…

  15. A double pendulum model of tennis strokes

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2011-05-01

    The physics of swinging a tennis racquet is examined by modeling the forearm and the racquet as a double pendulum. We consider differences between a forehand and a serve, and show how they differ from the swing of a bat and a golf club. It is also shown that the swing speed of a racquet, like that of a bat or a club, depends primarily on its moment of inertia rather than on its mass.

  16. Generalized Valon Model for Double Parton Distributions

    NASA Astrophysics Data System (ADS)

    Broniowski, Wojciech; Ruiz Arriola, Enrique; Golec-Biernat, Krzysztof

    2016-06-01

    We show how the double parton distributions may be obtained consistently from the many-body light-cone wave functions. We illustrate the method on the example of the pion with two Fock components. The procedure, by construction, satisfies the Gaunt-Stirling sum rules. The resulting single parton distributions of valence quarks and gluons are consistent with a phenomenological parametrization at a low scale.

  17. Floral double mesiodentes: A rare case report

    PubMed Central

    Singaraju, Gowri Sankar; Reddy, B. Rama Mohan; Supraja, G.; Reddy, K. Narayana

    2015-01-01

    Mesiodens is the most commonly erupting supernumerary in the midline between two maxillary central incisors. Mesiodentes is a rare condition when mesiodens erupt in multiples, which may present as either labial or palatal to permanent central incisors. We report a rare case of double mesiodentes (non-syndromic mesiodentes) with floret like appearance. The presence of mesiodens has functional and esthetic implications. Careful radiographic evaluation should be done to prevent complications during their extraction. PMID:25810670

  18. A Shifted Double-Diamond Titania Scaffold.

    PubMed

    Li, Hong; Liu, Ye; Cao, Xin; Han, Lu; Jiang, Chun; Che, Shunai

    2017-01-16

    Photonic crystals are expected to be metamaterials because of their potential to control the propagation of light in the linear and nonlinear regimes. Biological single-network, triply periodic constant mean curvature surface structures are considered excellent candidates owing to their large complete band gap. However, the chemical construction of these relevant structures is rare and developing new structures from thermodynamically stable double-network self-organizing systems is challenging. Herein, we reveal that the shifted double-diamond titania scaffold can achieve a complete band gap. The largest (7.71 %) band gap is theoretically obtained by shifting 0.332 c with the dielectric contrast of titania (6.25). A titania scaffold with similar shifted double-diamond structure was fabricated using a reverse core-shell microphase-templating system with an amphiphilic diblock copolymer and a titania source in a mixture of tetrahydrofuran and water, which could result in a 2.05-3.78 % gap.

  19. Ego, my double. (The Golyadkin phenomenon).

    PubMed

    Markidis, M

    1986-01-01

    A man is haunted by his Double. The great romantic tradition lends Dostoyevsky one of its dearest subjects. The Double, not only the exact physical duplication of the hero, but also a man with the same name, plots against Mr. Golyadkin, impersonates him both at work and in his private life, leads him to madness. This essay represents an attempt to clarify the stages of the adventurous relation of the subject to its Double, starting from the Hegelian "Phenomenology of the Spirit" and the Lacanian "Mirror Stage". If the construction of the human Ego is a narcissistic alienation to the image reflected by the mirror, the potential exit from the alienation lies in the Symbolic Order inhabited by the institution of the language. The Dostoyevskian hero gets into the Order of the language already trapped by the image of his mirror, by his projection. This projection (which constitutes his paranoia) will lead him to his annihilation, because Mr. Golyadkin cannot grasp its inner meaning.

  20. Double-polytropic closure in the magentosheath

    NASA Technical Reports Server (NTRS)

    Hau, L.-N.; Phan, T.-D.; Sonnerup, B. U. O.; Paschmann, G.

    1993-01-01

    The magnetosheath plasma is usually neither isotropic nor adiabatic. This paper contains an attempt to decribe its thermodynamic properties in terms of two polytropic laws, p(sub perpendicular)/rho B(exp gamma(sub perpendicular)-1) = C(sub perpendicular) and p(sub parallel)B(exp gamma(sub parallel)-1)/rho(exp gamma(sub parallel)) = C(sub parallel), such that for gamma(sub perpendicular) = 2, gamma(sub parallel) = 3 the usual Chew-Goldberger-Low double-adiabatic expressions are recovered and for gamma(sub perpendicular) = 1, gamma(sub parallel) = 1 double-isothermal conditions are obtained. Using data from the AMPTE/IRM spacecraft, we show that the subsolar magnetosheath plasma may be better described by the double-polytropic laws than by the mirror instability threshold, in particular in the low beta region near the magnetopause. The inferred polytropic exponents vary from event to event but are typically in the ranges of gamma(sub perpendicular) = 0.94 +/- 0.10 and gamma(sub parallel) = 1.14 +/- 0.13 for the 29 cases we have examined.

  1. Double-Difference Tomography for Sequestration MVA

    SciTech Connect

    Westman, Erik

    2008-12-31

    Analysis of synthetic data was performed to determine the most cost-effective tomographic monitoring system for a geologic carbon sequestration injection site. Double-difference tomographic inversion was performed on 125 synthetic data sets: five stages of CO2 plume growth, five seismic event regions, and five geophone arrays. Each resulting velocity model was compared quantitatively to its respective synthetic velocity model to determine an accuracy value. The results were examined to determine a relationship between cost and accuracy in monitoring, verification, and accounting applications using double-difference tomography. The geophone arrays with widely-varying geophone locations, both laterally and vertically, performed best. Additionally, double difference seismic tomography was performed using travel time data from a carbon sequestration site at the Aneth oil field in southeast Utah as part of a Department of Energy initiative on monitoring, verification, and accounting (MVA) of sequestered CO2. A total of 1,211 seismic events were recorded from a borehole array consisting of 22 geophones. Artificial velocity models were created to determine the ease with which different CO2 plume locations and sizes can be detected. Most likely because of the poor geophone arrangement, a low velocity zone in the Desert Creek reservoir can only be detected when regions of test site containing the highest ray path coverage are considered. MVA accuracy and precision may be improved through the use of a receiver array that provides more comprehensive ray path coverage.

  2. Seniority zero pair coupled cluster doubles theory.

    PubMed

    Stein, Tamar; Henderson, Thomas M; Scuseria, Gustavo E

    2014-06-07

    Coupled cluster theory with single and double excitations accurately describes weak electron correlation but is known to fail in cases of strong static correlation. Fascinatingly, however, pair coupled cluster doubles (p-CCD), a simplified version of the theory limited to pair excitations that preserve the seniority of the reference determinant (i.e., the number of unpaired electrons), has mean field computational cost and is an excellent approximation to the full configuration interaction (FCI) of the paired space provided that the orbital basis defining the pairing scheme is adequately optimized. In previous work, we have shown that optimization of the pairing scheme in the seniority zero FCI leads to a very accurate description of static correlation. The same conclusion extends to p-CCD if the orbitals are optimized to make the p-CCD energy stationary. We here demonstrate these results with numerous examples. We also explore the contributions of different seniority sectors to the coupled cluster doubles (CCD) correlation energy using different orbital bases. We consider both Hartree-Fock and Brueckner orbitals, and the role of orbital localization. We show how one can pair the orbitals so that the role of the Brueckner orbitals at the CCD level is retained at the p-CCD level. Moreover, we explore ways of extending CCD to accurately describe strongly correlated systems.

  3. Mechanical response of biopolymer double networks

    NASA Astrophysics Data System (ADS)

    Carroll, Joshua; Das, Moumita

    We investigate a double network model of articular cartilage (AC) and characterize its equilibrium mechanical response. AC has very few cells and the extracellular matrix mainly determines its mechanical response. This matrix can be thought of as a double polymer network made of collagen and aggrecan. The collagen fibers are stiff and resist tension and compression forces, while aggrecans are flexible and control swelling and hydration. We construct a microscopic model made of two interconnected disordered polymer networks, with fiber elasticity chosen to qualitatively mimic the experimental system. We study the collective mechanical response of this double network as a function of the concentration and stiffness of the individual components as well as the strength of the connection between them using rigidity percolation theory. Our results may provide a better understanding of mechanisms underlying the mechanical resilience of AC, and more broadly may also lead to new perspectives on the mechanical response of multicomponent soft materials. This work was partially supported by a Cottrell College Science Award.

  4. Perturbative quantum gravity in double field theory

    NASA Astrophysics Data System (ADS)

    Boels, Rutger H.; Horst, Christoph

    2016-04-01

    We study perturbative general relativity with a two-form and a dilaton using the double field theory formulation which features explicit index factorisation at the Lagrangian level. Explicit checks to known tree level results are performed. In a natural covariant gauge a ghost-like scalar which contributes even at tree level is shown to decouple consistently as required by perturbative unitarity. In addition, a lightcone gauge is explored which bypasses the problem altogether. Using this gauge to study BCFW on-shell recursion, we can show that most of the D-dimensional tree level S-matrix of the theory, including all pure graviton scattering amplitudes, is reproduced by the double field theory. More generally, we argue that the integrand may be reconstructed from its single cuts and provide limited evidence for off-shell cancellations in the Feynman graphs. As a straightforward application of the developed technology double field theory-like expressions for four field string corrections are derived.

  5. Double Alfvén waves

    NASA Astrophysics Data System (ADS)

    Webb, G. M.; Hu, Q.; Dasgupta, B.; Zank, G. P.

    2012-02-01

    Double Alfvén wave solutions of the magnetohydrodynamic equations in which the physical variables (the gas density ρ, fluid velocity u, gas pressure p, and magnetic field induction B) depend only on two independent wave phases ϕ1(x,t) and ϕ2(x,t) are obtained. The integrals for the double Alfvén wave are the same as for simple waves, namely, the gas pressure, magnetic pressure, and group velocity of the wave are constant. Compatibility conditions on the evolution of the magnetic field B due to changes in ϕ1 and ϕ2, as well as constraints due to Gauss's law ∇ · B = 0 are discussed. The magnetic field lines and hodographs of B in which the tip of the magnetic field B moves on the sphere |B| = B = const. are used to delineate the physical characteristics of the wave. Hamilton's equations for the simple Alfvén wave with wave normal n(ϕ), and with magnetic induction B(ϕ) in which ϕ is the wave phase, are obtained by using the Frenet-Serret equations for curves x=X(ϕ) in differential geometry. The use of differential geometry of 2D surfaces in a 3D Euclidean space to describe double Alfvén waves is briefly discussed.

  6. Why double-stranded RNA resists condensation.

    PubMed

    Tolokh, Igor S; Pabit, Suzette A; Katz, Andrea M; Chen, Yujie; Drozdetski, Aleksander; Baker, Nathan; Pollack, Lois; Onufriev, Alexey V

    2014-01-01

    The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to inter-DNA attraction and eventual condensation. Surprisingly, the condensation is suppressed in double-stranded RNA, which carries the same negative charge as DNA, but assumes a different double helical form. Here, we combine experiment and atomistic simulations to propose a mechanism that explains the variations in condensation of short (25 base-pairs) nucleic acid (NA) duplexes, from B-like form of homopolymeric DNA, to mixed sequence DNA, to DNA:RNA hybrid, to A-like RNA. Circular dichroism measurements suggest that duplex helical geometry is not the fundamental property that ultimately determines the observed differences in condensation. Instead, these differences are governed by the spatial variation of cobalt hexammine (CoHex) binding to NA. There are two major NA-CoHex binding modes--internal and external--distinguished by the proximity of bound CoHex to the helical axis. We find a significant difference, up to 5-fold, in the fraction of ions bound to the external surfaces of the different NA constructs studied. NA condensation propensity is determined by the fraction of CoHex ions in the external binding mode.

  7. Differences and correlations in knee and hip mechanics during single-leg landing, single-leg squat, double-leg landing, and double-leg squat tasks.

    PubMed

    Donohue, Michael R; Ellis, Samantha M; Heinbaugh, Erika M; Stephenson, Mitchell L; Zhu, Qin; Dai, Boyi

    2015-01-01

    Landing and squat tasks have been utilized to assess lower extremity biomechanics associated with anterior cruciate ligament loading and injury risks. The purpose of this study was to identify the differences and correlations in knee and hip mechanics during a single-leg landing, a single-leg squat, a double-leg landing, and a double-leg squat. Seventeen male and 17 female recreational athletes performed landings and squats when kinematic and kinetic data were collected. ANOVAs showed significant differences (p < 0.00001) for maximum knee flexion angles, maximum hip flexion angles, maximum knee abduction angles, maximum hip adduction angles, and maximum external knee abduction moments among squats and landings. For maximum knee and hip flexion angles, significant correlations (r ≥ 0.5, p ≤ 0.003) were observed between the two landings and between the two squats. For maximum knee abduction and hip adduction angles and maximum external knee abduction moments, significant correlations were mostly found between the two landings, and between the single-leg squat and landings (r ≥ 0.54, p ≤ 0.001). Individuals are likely to demonstrate different profiles of injury risks when screened using different tasks. While a double-leg landing should be considered as a priority in screening, a single-leg squat may be used as a surrogate to assess frontal plane motion and loading.

  8. Testing Intelligently Includes Double-Checking Wechsler IQ Scores

    ERIC Educational Resources Information Center

    Kuentzel, Jeffrey G.; Hetterscheidt, Lesley A.; Barnett, Douglas

    2011-01-01

    The rigors of standardized testing make for numerous opportunities for examiner error, including simple computational mistakes in scoring. Although experts recommend that test scoring be double-checked, the extent to which independent double-checking would reduce scoring errors is not known. A double-checking procedure was established at a…

  9. Double camera configuration Assistant program for meteor stations

    NASA Astrophysics Data System (ADS)

    De Cicco, Marcelo

    2016-04-01

    Recently we build a program to assist double cameras coverage configuration. The DOCCA (double camera configuration assistant) software is in its first version, and is based on mathematic language, but yet helps the network to improve double detections meteors. It takes in account the distance stations, the high of an ideal meteor brightness, and an average ‘r’ factor for a typical shower.

  10. Diapycnal Transport and Pattern Formation in Double-Diffusive Convection

    DTIC Science & Technology

    2015-12-01

    TRANSPORT AND PATTERN FORMATION IN DOUBLE-DIFFUSIVE CONVECTION by Erick L. Edwards December 2015 Dissertation Supervisor Timour Radko THIS...Dissertation 4. TITLE AND SUBTITLE DIAPYCNAL TRANSPORT AND PATTERN FORMATION IN DOUBLE- DIFFUSIVE CONVECTION 5. FUNDING NUMBERS 6. AUTHOR(S...is unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) This work analyzes the role of double-diffusive convection

  11. Algorithms for quad-double precision floating pointarithmetic

    SciTech Connect

    Hida, Yozo; Li, Xiaoye S.; Bailey, David H.

    2000-10-30

    A quad-double number is an unevaluated sum of four IEEE double precision numbers, capable of representing at least 212 bits of significance. We present the algorithms for various arithmetic operations (including the four basic operations and various algebraic and transcendental operations) on quad-double numbers. The performance of the algorithms, implemented in C++, is also presented.

  12. The Double-Needle Felling Machine. Module 17.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on the double-needle felling machine, one in a series dealing with industrial sewing machines, their attachments, and operation, covers two topics: performing special operations on the double-needle felling machine (straight seams) and performing special operations on the double-needle felling machine (curved flat-felled seams). For…

  13. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  14. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  15. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  16. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  17. The double identity of doubling: Evidence for the phonology-morphology split.

    PubMed

    Berent, Iris; Bat-El, Outi; Vaknin-Nusbaum, Vered

    2017-04-01

    Duality of patterning, is, by hypothesis, a universal design feature of language. Every language constructs words from meaningful units (morphemes), which, in turn, are comprised of meaningless phonological elements (e.g., segments, syllables). But whether the language faculty does, in fact, include a separate morphological level, distinct from the phonology, is a matter of controversy. To elucidate the role of morphology, here we ask whether morphological forms are constrained by putatively universal combinatorial principles, distinct from those applying to phonological patterns. Our research exploits the structural ambiguity of doubling. Doubling (e.g., trafraf) is open to two competing interpretations-as either a purely phonological form, or as a complex morphological structure that is systematically linked to meaning (e.g., trafraf is the diminutive of traf). Our experiments show that responses to doubling (trafraf) shift radically, depending on its level of analysis. Viewed as a meaningless phonological form, doubling is dispreferred irrespective of its kind (i.e., trafraf is as bad as traftaf, even though the latter violates a morphological constraint on contiguity). But once doubling is systematically linked to meaning (i.e., as a morphological structure), the doubling dislike shifts into a reliable preference, and an additional constraint on its contiguity arises (i.e., trafraf>traftaf). Remarkably, the dissociation between morphological and phonological doubling emerges regardless of whether morphological reduplication is abundant in participants' language (in Hebrew) or relatively rare (in English). These results suggest the existence of distinct linguistic constraints that preferentially target the morphological vs. phonological levels. We discuss various explanations for the origins of these restrictions.

  18. One-Cell Doubling Evaluation by Living Arrays of Yeast, ODELAY!

    PubMed Central

    Herricks, Thurston; Dilworth, David J.; Mast, Fred D.; Li, Song; Smith, Jennifer J.; Ratushny, Alexander V.; Aitchison, John D.

    2016-01-01

    Cell growth is a complex phenotype widely used in systems biology to gauge the impact of genetic and environmental perturbations. Due to the magnitude of genome-wide studies, resolution is often sacrificed in favor of throughput, creating a demand for scalable, time-resolved, quantitative methods of growth assessment. We present ODELAY (One-cell Doubling Evaluation by Living Arrays of Yeast), an automated and scalable growth analysis platform. High measurement density and single-cell resolution provide a powerful tool for large-scale multiparameter growth analysis based on the modeling of microcolony expansion on solid media. Pioneered in yeast but applicable to other colony forming organisms, ODELAY extracts the three key growth parameters (lag time, doubling time, and carrying capacity) that define microcolony expansion from single cells, simultaneously permitting the assessment of population heterogeneity. The utility of ODELAY is illustrated using yeast mutants, revealing a spectrum of phenotypes arising from single and combinatorial growth parameter perturbations. PMID:27856698

  19. Double Double Cation Order in the High-Pressure Perovskites MnRMnSbO6.

    PubMed

    Solana-Madruga, Elena; Arévalo-López, Ángel M; Dos Santos-García, Antonio J; Urones-Garrote, Esteban; Ávila-Brande, David; Sáez-Puche, Regino; Attfield, J Paul

    2016-08-01

    Cation ordering in ABO3 perovskites adds to their chemical variety and can lead to properties such as ferrimagnetism and magnetoresistance in Sr2 FeMoO6 . Through high-pressure and high-temperature synthesis, a new type of "double double perovskite" structure has been discovered in the family MnRMnSbO6 (R=La, Pr, Nd, Sm). This tetragonal structure has a 1:1 order of cations on both A and B sites, with A-site Mn(2+) and R(3+) cations ordered in columns and Mn(2+) and Sb(5+) having rock salt order on the B sites. The MnRMnSbO6 double double perovskites are ferrimagnetic at low temperatures with additional spin-reorientation transitions. The ordering direction of ferrimagnetic Mn spins in MnNdMnSbO6 changes from parallel to [001] below TC =76 K to perpendicular below the reorientation transition at 42 K at which Nd moments also order. Smaller rare earths lead to conventional monoclinic double perovskites (MnR)MnSbO6 for Eu and Gd.

  20. Double standards for sexual jealousy : Manipulative morality or a reflection of evolved sex differences?

    PubMed

    Paul, L; Foss, M A; Baenninger, M A

    1996-09-01

    This work tests two conflicting views about double standards: whether they reflect evolved sex differences in behavior or a manipulative morality serving male interests. Two questionnaires on jealous reactions to mild (flirting) and serious (cheating) sexual transgressions were randomly assigned to 172 young women and men. One questionnaire assessed standards for appropriate behavior and perceptions of how young women and men usually react. The second asked people to report how they had reacted or, if naive, how they would react. The questions concerned anger at and blame of partner and rival and the self-oriented responses of loss of self-esteem, feelings of hurt, and fear of losing the partner. As predicted by the idea of manipulative morality, both sexes advanced sets of double standards that serve the interests of their own sex at the expense of the opposite sex. Much of the data contradict the idea of a match between double standards and evolved sex differences. First, subjects who set self-serving double standards did not perceive gender differences in jealous reactions. Second, there were few gender differences in judgments regarding jealous responses. Third, in contrast with the familiar double standard, women were more aggressively reactive to a flirting rival than men. Fourth, self-reports of the strength of aggressive jealous reactions suggest that women's behavior is stronger than the prescriptions for it. These data suggest that double standards represent a communication strategy which assists men's control of women. The data on jealous reactions were interpreted in terms of the degree of threat to fitness posed by infidelity in different situations.