Observation of the Bc meson in the exclusive decay Bc→J/ψπ

A fully reconstructed Bc→J/ψπ signal is observed with the D0 detector at the Fermilab Tevatron pp̄ collider using 1.3fb-1 of integrated luminosity. The signal consists of 54±12 candidates with a significance that exceeds 5 standard deviations, and confirms earlier observations of this decay. The measured mass of the Bc meson is 6300±14(stat)±5(syst) MeV/c2. © 2008 The American Physical Society.

Search for decay of a fermiophobic higgs boson hf→ y y with the D0 detector at s=1.96a TeV

We report the results of a search for a narrow resonance decaying into two photons in 1.1fb-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider during the period 20022006. We find no evidence for such a resonance and set a lower limit on the mass of a fermiophobic Higgs boson of mhf>100GeV at the 95% C.L. This exclusion limit exceeds those obtained in previous searches at the Fermilab Tevatron and covers a significant region of the parameter space B(hf→I I ) vs mhf which was not accessible at the CERN Large Electron-Positron Collider. © 2008 The American Physical Society.

Measurement of the inclusive jet cross section in pp̄ collisions at s=1.96TeV

We report on a measurement of the inclusive jet cross section in pp̄ collisions at a center-of-mass energy s=1.96TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0.70fb-1. The data cover jet transverse momenta from 50 to 600 GeV and jet rapidities in the range -2.4 to 2.4. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations. © 2008 The American Physical Society.

Search for long-lived particles decaying into electron or photon pairs with the D0 detector

In this Letter we report on a search for long-lived particles that decay into final states with two electrons or photons. Such long-lived particles arise in a variety of theoretical models, such as hidden valleys and supersymmetry with gauge-mediated breaking. By precisely reconstructing the direction of the electromagnetic shower we are able to probe much longer lifetimes than previously explored. We see no evidence of the existence of such long-lived particles and interpret this search as a quasi model-independent limit on their production cross section, as well as a limit on a long-lived fourth generation quark. © 2008 The American Physical Society.

Adherence of Streptococcus mutans to uncoated and saliva-coated glass-ceramics and composites

This study sought to investigate the surface roughness and the adherence of Streptococcus mutans (in the presence and absence of saliva) to ceramics and composites. The early dental biofilms formed in situ on the materials were illustrated, using scanning electron microscopy (SEM). Feldspathic and leucite/feldspathic ceramics and microhybrid and microfilled composites were evaluated. Human dental enamel was used as the control. Standardized specimens of the materials were produced and surface roughness was analyzed. The adhesion tests were carried out in 24-well plates and colony forming units (CFU/mL) were evaluated. Values of roughness (μm) and adherence (CFU/mL) were analyzed statistically. Of all the surfaces tested, enamel was the roughest. Leucite/feldspathic ceramics were rougher than the feldspathic ceramic, while composites were similar statistically. Enamel offered the highest level of adherence to uncoated and saliva-coated specimens, while the leucite/feldspathic ceramic demonstrated greater adherence than the feldspathic ceramic and the composites were similar statically. The rougher restorative materials increased the adherence of S, mutans on the material surfaces.

Performance of different genotypes of vegetable soybeans in Jaboticabal-SP

The study was conducted in the field, in the experimental area of the Section of Crop Production and Aromatic Medicinal Plants, belonging to the Faculty of Agricultural and Veterinary Sciences, Jaboticabal Campus-SP. The aim of the study was to assess the performance of seven genotypes of vegetable soybeans in Jaboticabal-SP. The experiment was carried out in a complete randomized block design with seven treatments (genotypes) and four replications. The genotypes examined were: CNPSOI, JLM003, JLM010, JLM018, JLM019, JLM024 and BRS216. The seeds were obtained from EMBRAPA-Soja and EMBRAPA- Hortaliças, and planted in Styrofoam trays with 128 cells containing Plantmax Hortaliças® as substrate. Transplanting occurred 10 d after seeding when the seedlings showed 2 or 3 definitive leaves and about 12 cm in height, demonstrating that the soil had been properly prepared according to the recommendations for this crop. Pests and diseases were adequately controlled in the event of their occurrence in the experimental area and in accordance with technical recommendations for the chemical products utilized. Collections were carried out based on the maturation of the pods, according to the scale of Fehr and Caviness (1977) adapted by Costa and Marchezan (1982), when the pods reached the reproductive stage R6. The parameters determined were mean precocity, height of the first pod, mean number of pods per plant, mean number of seeds per pod, fresh weight of 100 seeds and total yield of immature grains. Based on the results obtained, the genotypes JLM003 and JLM010 were found to be most indicated for growing vegetable soybeans, because of their capacity to produce immature grains of 1090 and 848 g·m-2, respectively, and fresh weights for 100 seeds of 62.20 and 68.19 g, respectively.

Search for neutral higgs bosons in Multi-b-Jet events in pp̄ collisions at s=1.96TeV

Data recorded by the D0 experiment at the Fermilab Tevatron Collider are analyzed to search for neutral Higgs bosons produced in association with b quarks. This production mode can be enhanced in the minimal supersymmetric standard model (MSSM). The search is performed in the three b quark channel using multijet triggered events corresponding to an integrated luminosity of 1fb-1. No statistically significant excess of events with respect to the predicted background is observed and limits are set in the MSSM parameter space. © 2008 The American Physical Society.

Effectiveness of six different disinfectants on removing five microbial species and effects on the topographic characteristics of acrylic resin

Purpose: The aim of this study was to evaluate the effectiveness of disinfectant solutions (1% sodium hypochlorite, 2% chlorhexidine digluconate, 2% glutaraldehyde, 100% vinegar, tabs of sodium perborate-based denture cleanser, and 3.8% sodium perborate) in the disinfection of acrylic resin specimens (n = 10/group) contaminated in vitro by Candida albicans, Streptococcus mutans, S. aureus, Escherichia coli, or Bacillus subtilis as measured by residual colony-forming unit (CFU). In a separate experiment, acrylic resin was treated with disinfectants to monitor potential effects on surface roughness, Ra (μm), which might facilitate microbial adherence. Materials and Methods: Three hundred fifty acrylic resin specimens contaminated in vitro with 1×10 6 cells/ml suspensions of standard strains of the cited microorganisms were immersed in the disinfectants for 10 minutes; the control group was not submitted to any disinfection process. Final counts of microorganisms per ml were performed by plating method for the evaluation of microbial level reduction. Results were compared statistically by ANOVA and Tukey's test (p ≤ 0.05). In a parallel study aiming to evaluate the effect of the tested disinfectant on resin surface, 60 specimens were analyzed in a digital rugosimeter before and after ten cycles of 10-minute immersion in the disinfectants. Measurements of superficial roughness, Ra (μm), were compared statistically by paired t-test (p ≤ 0.05). Results: The results showed that 1% sodium hypochlorite, 2% glutaraldehyde, and 2% chlorhexidine digluconate were most effective against the analyzed microorganisms, followed by 100% vinegar, 3.8% sodium perborate, and tabs of sodium perborate-based denture cleanser. Superficial roughness of the specimens was higher after disinfection cycles with 3.8% sodium perborate (p = 0.03) and lower after the cycles with 2% chlorhexidine digluconate (p = 0.04). Conclusion: Within the limits of this experiment, it could be concluded that 1% sodium hypochlorite, 2% glutaraldehyde, 2% chlorexidine, 100% vinegar, and 3.8% sodium perborate are valid alternatives for the disinfection of acrylic resin. © 2008 by The American College of Prosthodontists.

Microbial distribution in the root canal system after periapical lesion induction using different methods

The aim of this study was to evaluate the microbial distribution in the root canal system after periapical lesion induction in dogs' teeth using different methods. Fifty-two root canals were assigned to 4 groups (n=13). Groups I and II: root canals were exposed to the oral cavity for 180 days; groups III and IV: root canals were exposed for 7 days and then the coronal openings were sealed for 53 days. The root apices of groups I and III were perforated, while those of groups II and IV remained intact. After the experimental periods, the animals were euthanized and the anatomic pieces containing the roots were processed and stained with the Brown & Brenn method to assess the presence and distribution of microorganisms. The incidence of microorganisms at different sites of the roots and periapical lesions was analyzed statistically by the chi-square test at 5% significance level. All groups presented microorganisms in the entire root canal system. A larger number of microorganisms was observed on the root canal walls, apical delta and dentinal tubules (p<0.05), followed by cementum and cemental resorption areas. In spite of the different periods of exposure to the oral environment, the methods used for induction of periapical periodontitis yielded similar distribution of microorganisms in the root canal system.

Effect of plastic film mulch on the production of butterhead lettuce cultivars under protected cultivation

The study was performed in a greenhouse with the aim of evaluating the production of butterhead lettuce cultivars with and without plastic film mulch in the summer. The cultivars studied were 'Elisa', 'Lídia', 'Herman' and 'Luísa'. The experimental design was a split plot, in which the main plot was plastic film mulch (with or without black polyethylene film) and the subplots were the cultivars, with three repetitions. The seedlings were grown in Styrofoam trays of 288 cells and transplanted 25 days after seeding in a space of 25 × 25 cm. Harvests were carried out 45 days after transplanting and the following variables were determined: fresh and dry weights of the aerial part, number of leaves per plant, plant height and the longitudinal and transverse diameters of the plant. Significant differences were found only among the cultivars for the characteristics studied, with no cover × cultivar interaction. Fresh weight of the aerial part of 'Lídia' (270.9 g) was greater than that of 'Herman' (142.5 g), but did not differ from those of 'Luísa' (229.8 g) or 'Elisa' (204.8). The dry weight of the aerial part of 'Lídia' (12.4 g) differed statistically only with respect to that of 'Herman' (7.9 g). The cultivars 'Luísa' and 'Elisa' had an aerial part dry weight of 11.4 and 11.2 g, respectively. The number of leaves per plant of the cultivars 'Luísa' (45.1) and 'Elisa' (43.0) was higher than for 'Herman' (24.05), but did not differ from that of the cultivar 'Lídia' (39.5). The mean transverse and longitudinal diameters, as well as the mean height of the plants, showed that 'Lídia', 'Elisa' and 'Luísa' had the greatest values. The cultivars 'Lídia', 'Elisa' and 'Luísa' were the most productive and plastic film mulch had no effect on lettuce production under protected cultivation.

Response of rootstocks to stem canker and the production and quality of melon under protected cultivation

Two tests were performed. In the first, resistance to Didymella bryoniae was determined for the following genotypes: the pumpkins 'Ikky', 'Agroceres', 'Kirameki' and 'Shelper', watermelon progenies 1a, 2a, 3a, 5a, 1b, 2b, 3b and 5b, and 'Gherkin' (C. anguria). The plants were inoculated with the fungus during transplanting. The evaluations of the test were performed every 15 d according to a scoring scale adopted by Dusi et al. (1994). The second test examined compatibility among the rootstocks x grafts, and their effects on production. The rootstocks, 5 pumpkins including 'Ikky', 'Agroceres', 'Kirameki', 'Shelper', six watermelon progenies 1a, 2a, 5a, 1b, 2b and 5b, and one 'Gherkin', were planted one week before planting of the grafted 'Bônus No. 2' melon. The experiments were carried out with 12 treatments, including the control ('Bônus No. 2') with 3 replications with 14 grafted plants per each replication. For the first test, the first three evaluations (at 15, 30 and 45 d after inoculation) did not show characteristic lesions of stem canker, but progeny 3b was found to be susceptible in evaluations performed at 60 and 75 d after inoculation. Progeny 3a demonstrated intermediate susceptibility, while progenies 1a, 2a, 5a, 1b, 2b and 5b, the pumpkins 'Kirameki', 'Shelper', 'Ikky' and 'Agroceres', and 'Gherkin', showed resistance to Didymella bryoniae. In the second test, watermelon progenies 1a, 5a, 1b and 2b, and the pumpkins 'Kirameki', 'Shelper', 'Ikky' and 'Agroceres' showed a level of grafting success of 100%, while results with progenies 2a and 5b, and 'Gherkin' were different in grafting success, respectively 91.67, 98.33 and 43.33%. For other fruit parameters, weight, longitudinal and transverse diameters, pulp thickness and level of total soluble solids, there were no differences among the treatments.

Compatibility of grafting in the melon cv. bônus No. 2, and effects on production

Twelve rootstocks were evaluated: 1) pumpkin 'Big Power' (Cucurbita ntoschata); 2) pumpkin 'Seca' (Cucurbita moschata); 3) bottle gourd 'Longa' (Lagenaria siceraria); 4) 'Cachi' (Lagenaria siceraria); 5) bottle gourd 'Marimba' (Lagenaria siceraria); 6) 'Mogango' (Cucurbita maxima); 7) pumpkin 'Kirameki' (Cucurbita moschata); 8) pumpkin 'Caravela' (Cucurbita moschata); 9) pumpkin 'Shelper' (Cucurbita moschata); 10) 'Gherkin' (Cucumis anguria); 11) 'Loofah' (Luffa cylindrica); and 12) pumpkin 'Goianinha' (Cucurbita moschata) with respect to compatibility with melon yield, and the production and quality of fruits from cv. Bônus No. 2, non-grafted and grafted with 9 of these rootstocks (1, 2, 4, 5, 6, 7, 9, 10 and 11). The bottle gourd 'Marimba' provided the highest percentage of grafting success between the vine and rootstock. The rootstocks 1, 2, 3, 4 and 7 did not differ from bottle gourd 'Marimba', therefore also indicating good compatibility with the melon cv. Bônus No. 2. For height of the plants, it was shown in the first evaluation that rootstock 5 produced a greater height of the plant, differing only from rootstocks 7, 8, 9, 10 and 11 and non-grafted cv. Bônus No. 2. In the second evaluation, 'Big Power' showed the greatest value for height of the plant, differing only from combinations with 'Cachi', 'Mogango', 'Shelper' and 'Loofah'. With regard to number of leaves, in the first evaluation rootstocks 3, 4 and 6 had the greatest number of leaves, but in the second 4, 9 and 11 had the greatest. For dry weight of the stem, the greatest value was obtained with 'Mogango' in the first evaluation and with 'Big Power' in the second. For leaf area of the plants, a difference was found among the treatments only in the first evaluation, where the combination with bottle gourd 'Longa' showed a greater leaf area, but did not differ from the combinations with rootstocks 1, 4, 5 and 6. Differences were demonstrated among the treatments only for the transverse diameter of the fruit, where the combination with rootstock bottle gourd 'Marimba' showed the greatest value, differing only from the combination with 'Gherkin'. There were no significant differences for the mean longitudinal diameter, pulp thickness and total soluble solids among the treatments studied.

Antimicrobial activity of endodontic sealers based on calcium hydroxide and MTA.

The aim of this study was to evaluate the antimicrobial activity of a new root canal sealer containing calcium hydroxide (Acroseal) and the root canal sealer based on MTA (Endo CPM Sealer), in comparison with traditional sealers (Sealapex, Sealer 26 and Intrafill) and white MTA-Angelus, against five different microorganism strains. The materials and their components were evaluated after manipulation, employing the agar diffusion method. A base layer was made using Müller-Hinton agar (MH) and wells were made by removing agar. The materials were placed into the wells immediately after manipulation. The microorganisms used were: Micrococcus luteus (ATCC9341), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853), Candida albicans (ATCC 10231), and Enterococcus faecalis (ATCC 10541). The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. The results showed that Sealapex and its base paste, Sealer 26 and its powder, Endo CPM Sealer and its powder, white MTA and its powder all presented antimicrobial activity against all strains. Intrafill and its liquid presented antimicrobial activity against all strains except P. aeruginosa and Acroseal was effective only against M. luteus and S. aureus.

Phenotypic characterization of Candida spp. isolates from chronic periodontitis patients

Aim: Several typing methods for Candida spp. have been suggested in the literature in order to distinguish isolates for studies about the virulence or infection routes of these microorganisms and, in particular, for epidemiological purposes. The aim of this study was to establish a comparison between the phenotypic profile of oral Candida isolates from periodontitis patients and control individuals. Methods: The morphotyping and biotyping of 35 C. albicans isolates obtained from chronic periodontitis patients and 48 isolates from control individuals were performed. For morphotyping, the isolates were plated on malt extract agar and incubated for 10 days. Sixteen different morphotypes were observed for C. albicans, the most frequently observed being 0000 and 0001. Results: Biotype 0000 (complete absence of fringe) was most prevalent among the isolates obtained from periodontitis patients compared to those from control individuals, with statistical significance. Biotyping revealed 5 different biotypes with higher prevalence of the biotype 357 among the isolates from control and periodontitis groups. Conclusions: The results obtained by biotyping of the isolates did not permit to differentiate a characteristic model related to periodontal disease, whilst the morphotype 0000 was most frequently isolated from periodontitis patients.

Search for third generation scalar leptoquarks decaying into τb

We have searched for third generation leptoquarks (LQ3) using 1.05fb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider operating at s=1.96TeV. We set a 95% C.L. lower limit of 210 GeV on the mass of a scalar LQ3 state decaying solely to a b quark and a τ lepton. © 2008 The American Physical Society.