200 research outputs found

    Manner of Apical Meristem Destruction Affects Growth, Reproduction, and Survival of Sea Oxeye Daisy

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    Although herbivory may result in plant death, the mode and timing of damage may produce variable wounding responses in the attacked plant. In this study, effects of different types of apical meristem damage on growth and performance of sea oxeye daisy Borrichia frutescens (L.) DC were compared. Damage involved either clipping or galling of the apical meristem by the gall midge Asphondylia borrichiae Rossi and Strong. Apical dominance was relatively weak before flowering and stronger in short ramets that were shaded by taller neighbors later in the season. Clipped ramets delayed sprouting new stems, and galled ramets sprouted new stems quickly compared to intact ramets, but final stem counts were similar across treatments. Clipping significantly delayed flowering, reduced seed head ripening time, and resulted in fewer seed heads and seeds. Galling did not significantly impact reproduction compared to intact ramets. Nitrogen supplementation significantly increased stem count and seed count and lengthened seed ripening time. Borrichia frutescens responds differently to clipping versus galling by A. borrichiae and better tolerates galling in terms of nonreproductive performance and survival. Galling from A. borrichiae likely prevents Borrichia frutescens from flowering, which suggests resource regulation of meristems by the midge

    Evaluation of Patent Foramen Ovale in Young Adults with Cryptogenic Stroke

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    <p><br /><strong>BACKGROUND</strong>: Stroke is a leading cause of death and long-term disability worldwide.<br />Although a minority of ischemic strokes in the community affect younger adults, up to 40% of<br />acute ischemic strokes in young adults are cryptogenic in nature, that is, no cause is determined.<br />Underlying pathologies of stroke of unknown cause are multiple, including patent foramen ovale<br />(PFO). The PFO is the most common defect of atrial septum of the heart. This study evaluated<br />the frequency of PFO in brain stroke with unknown etiology in patients younger than 50 years of<br />age in Kerman.<br /><strong>METHODS</strong>: This cross-sectional study was done in Shafa Medical Center of Kerman University<br />of Medical Sciences in 2008. For detection of the PFO, we used agitated saline test with<br />transcranial Doppler sonography in brain stroke patients with unknown etiology and also a<br />control group (normal persons).<br /><strong>RESULTS</strong>: PFO was found in 53% of patients. No significant difference was observed between<br />sexes. The rate in the control group was 20%. Patients with large PFO had 2 or more attacks of<br />stroke. Subjects in the control group did not have large PFO.<br /><strong>CONCLUSION</strong>: One of the most important underlying causes in young adults with cryptogenic<br />stroke is PFO. It is better to prescribe antiplatelet drugs in patients with the first attack of<br />stroke, but as for patients with recurrent stroke, closure of PFO must be considered.</p><p><strong>Keywords</strong>: Stroke, Young Adults, Patent Foramen Ovale, Agitated Normal Saline Test.</p

    Effect of different concentrations of specific inhibitor of matrix metalloproteinases on the shear bond strength of self-adhesive resin cements to dentin

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    Considering the probability of chemical and enzymatic reactions between matrix metalloproteinases (MMPs) in the dentin structure and their specific inhibitors, the aim of the present study was to evaluate the effect of different concentrations of specific inhibitor of MMPs (galardin) on the shear bond strength of self-adhesive resin cements to dentin. Forty-eight sound human premolars were mounted in self-cured acrylic resin after removal of the enamel on the buccal and lingual surfaces. The dentin surfaces achieved were polished and prepared with 600-grit silicon carbide paper. The samples were divided into 3 groups (n=16) based on the concentration of galardin used (with no galardin, galardin at a high concentration and galardin at a low concentration). In addition, 96 composite resin blocks, measuring 3 mm in height and diameter, were prepared. The composite resin blocks were bonded to the buccal and lingual surface dentin with Rely-X Unicem (RXC) and Speed CEM (SPC) self-adhesive resin cements, respectively, according to manufacturers? instructions. After 24 hours of storage in distilled water at 37°C, the shear bond strength values were determined in MPa and fracture modes were evaluated under a stereomicroscope. Data were analyzed with two-way ANOVA and post-hoc Bonferroni test (?=0.05). The shear bond strength of galardin at high concentration was significantly higher than that in the control group and galardin at a low concentrations (P<0.001). In addition, galardin at a low concentration exhibited higher shear bond strength compared to the control group (P=0.005). Furthermore, higher shear bond strength values were reported with the use of RXC compared to SPC (P<0.001). Irrigation with galardin increased the shear bond strength of self-adhesive resin cements to dentin and this increase had a direct relationship with the concentration of galardin in the solution

    Effect of intraradicular reinforcement strategies on the fracture strength of endodontically treated anterior teeth with overflared canals

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    This study is done to evaluate the effect of different reinforcement techniques of overflared root canals with fiber posts on the fracture resistance of endodontically treated anterior teeth. It also introduces a new technique for simultane

    Effect of 15% carbamide peroxide bleaching gel on color stability of giomer and microfilled composite resin: an in vitro comparison

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    Objectives: The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study. Study design: Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces. Then a spectrophotometer was used to measure L* (lightness), a* (redness, greenness) and b* (blueness, yellowness) color coordinates of all the discs. Subsequently, the specimens were subjected to 15% carbamide peroxide bleaching gel. After measuring the color coordinates once again, color changes (DE*) were calculated by the CIELAB system. Six specimens from each material (three specimens before bleaching agent application and three specimens thereafter) were viewed under an atomic force microscope (AFM) for surface topography evaluation. Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests at a=0.05. Results: There were no statistically significant differences in color changes (DE*) between the two materials (P>0.05). In addition, no significant differences were detected in surface roughness between composite resin and giomer discs before and after bleaching (P>0.05 for both). However, in both materials the differences in surface roughness were significant before and after bleaching procedures (P<0.001). Conclusions: Based on the results of the present study it was concluded that 15% carbamide peroxide does not induce clinically detectable color changes in composite resin and giomer despite an increase in surface roughness

    Effect of sodium ascorbate on the bond strength of all-in-one adhesive systems to NaOCl-treated dentin

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    Background: Ascorbic acid and its salts are low-toxicity products, which are routinely used in food industries as antioxidants. The aim of the present study was to evaluate the effect of 10% sodium ascorbate on the bond strength of two all-in-one adhesive systems to NaOCl-treated dentin. Material and Methods: After exposing the dentin on the facial surface of 90 sound human premolars and mounting in an acrylic resin mold, the exposed dentin surfaces were polished with 600-grit SiC paper under running water. Then the samples were randomly divided into 6 groups of 15. Groups 1 and 4 were the controls, in which no surface preparation was carried out. In groups 2 and 5 the dentin surfaces were treated with 5.25% NaOCl alone for 10 minutes and in groups 3 and 6 with 5.25% NaOCl for 10 minutes followed by 10% sodium ascorbate for 10 minutes. Then composite resin cylinders, measuring 2 mm in diameter and 2 mm in height, were bonded on the dentin surfaces in groups 1, 2 and 3 with Clearfil S 3 Bond and in groups 4, 5 and 6 with Adper Easy One adhesive systems according to manufacturers’ instructions. The samples were stored in distilled water for 24 hours at 37°C and then thermocycled. Finally, the samples underwent shear bond strength test in a universal testing machine at a strain rate of 1 mm/min. Data were analyzed with two-way ANOVA and post hoc Tukey tests at α=0.05. Results: The differences between groups 1 and 2 ( P =0.01), 1 and 5 ( P =0.003). 1 and 6 ( P =0.03) and 4 and 5 ( P =0.03) were statistically significant. Two-by-two comparisons did not reveal any significant difference between other groups ( P >0.05). Conclusions: Use of 10% sodium ascorbate for 10 minutes restored the decreased bond strength of the adhesive systems to that of the control groups

    Effect of different application strategies of universal adhesive used for immediate and delayed dentin sealing on the microtensile bond strength of self-adhesive resin cement to dentin with and without aging

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    Bond strength of indirect restorations is a very important issue that should be given special attention. Immediate dentin sealing (IDS) technique has been suggested in recent years. The aim of the present study was to investigate the effect of different

    EVALUATION OF PATENT FORAMEN OVALE IN YOUNG ADULTS WITH CRYPTOGENIC STROKE

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    BACKGROUND: Stroke is a leading cause of death and long-term disability worldwide. Although a minority of ischemic strokes in the community affect younger adults, up to 40% of acute ischemic strokes in young adults are cryptogenic in nature, that is, no cause is determined. Underlying pathologies of stroke of unknown cause are multiple, including patent foramen ovale (PFO). The PFO is the most common defect of atrial septum of the heart. This study evaluated the frequency of PFO in brain stroke with unknown etiology in patients younger than 50 years of age in Kerman. METHODS: This cross-sectional study was done in Shafa Medical Center of Kerman University of Medical Sciences in 2008. For detection of the PFO, we used agitated saline test with transcranial Doppler sonography in brain stroke patients with unknown etiology and also a control group (normal persons). RESULTS: PFO was found in 53% of patients. No significant difference was observed between sexes. The rate in the control group was 20%. Patients with large PFO had 2 or more attacks of stroke. Subjects in the control group did not have large PFO. CONCLUSION: One of the most important underlying causes in young adults with cryptogenic stroke is PFO. It is better to prescribe antiplatelet drugs in patients with the first attack of stroke, but as for patients with recurrent stroke, closure of PFO must be considered

    In vitro evaluation of human endometrial stem cell-derived osteoblast-like cells’ behavior on gelatin/collagen/bioglass nanofibers’ scaffolds

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    New biomimetic nanocomposite scaffold was prepared by the combination of nanofibrilar bioglass containing copper ion as the inorganic phase and gelatin/collagen as the organic phase of bone tissue. In this study for fabrication of the scaffold, freeze drying and electrospinning methods were used, and genipin was used as the cross-linking agent for increasing the mechanical properties of the scaffold. The growth and viability of human endometrial stem cell-derived osteoblast-like cells were investigated on this biomimetic scaffold. Cellular biocompatibility assays illustrated that this scaffold has more viabilities and osteoblast growths in comparison with two-dimensional culture. Copper ion increased growth of the osteoblasts on nanocomposite scaffold containing nanofibrous bioglass. Thus, the results obtained from this study indicate that the prepared scaffold is suitable for osteoblast growth and attachment; thus, potentially, this nanocomposite scaffold is an appropriate scaffold for bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2210–2219, 2016

    The effect of pre-heating on monomer elution from bulk-fill resin composites

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    The present study was aimed to evaluate the effect of pre-heating of bulk -fill resin composites on monomer elution from them. Three different types of resin composites were used including Tetric N-Ceram Bulk Fill, X-tra Fill and X-tra Base. 10 cylindrical samples were prepared from each resin composites. Before light curing, 5 samples were pre-heated until reaching 68?C, then 5 other samples were polymerized at room temperature. After 24 hours, release of UDMA, TEGDMA and BIS-GMA monomers were measured by High-Performance Liquid Chromatography analysis. Data analysis was performed by two-way ANOVA test, Games-Howell and Sidak post hoc tests. Pre-heating did not have any statistically significant effect on the mean values of UDMA, TEGDMA and Bis-GMA elution (p>0.05). The greatest amount of released Bis-GMA and UDMA was obtained from Tetric N-Ceram Bulk-fill composite. The greatest amount of released TEGDMA was obtained from X-tra Fill composite. X-tra Base composite showed the lowest amount of monomer release (P<0.001). Pre-heating did not have any effect on monomer release from bulk-fill resin composites. Moreover, the amount and the type of monomers released from various bulk-fill resin composites were not similar
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