33 research outputs found
Is there a circumbinary planet around NSVS 14256825?
The cyclic behaviour of (O-C) residuals of eclipse timings in the sdB+M
eclipsing binary NSVS 14256825 was previously attributed to one or two
Jovian-type circumbinary planets. We report 83 new eclipse timings that not
only fill in the gaps in those already published but also extend the time span
of the (O-C) diagram by three years. Based on the archival and our new data
spanning over more than 17 years we re-examined the up to date system (O-C).
The data revealed systematic, quasi-sinusoidal variation deviating from an
older linear ephemeris by about 100 s. It also exhibits a maximum in the (O-C)
near JD 2,456,400 that was previously unknown. We consider two most credible
explanations of the (O-C) variability: the light propagation time due to the
presence of an invisible companion in a distant circumbinary orbit, and
magnetic cycles reshaping one of the binary components, known as the Applegate
or Lanza-Rodono effect. We found that the latter mechanism is unlikely due to
the insufficient energy budget of the M-dwarf secondary. In the framework of
the third-body hypothesis, we obtained meaningful constraints on the Keplerian
parameters of a putative companion and its mass. Our best-fitting model
indicates that the observed quasi-periodic (O-C) variability can be explained
by the presence of a brown dwarf with the minimal mass of 15 Jupiter masses
rather than a planet, orbiting the binary in a moderately elliptical orbit (~
0.175) with the period of ~ 10 years. Our analysis rules out two planets model
proposed earlier.Comment: 17 pages, 9 figures, 4 tables, accepted to A
Polarization and Spectral Energy Distribution in OJ 287 during the 2016/17 Outbursts
We report optical photometric and polarimetric observations of the
blazar OJ 287 gathered during 2016/17. The high level of activity,
noticed after the General Relativity Centenary flare, is argued to be
part of the follow-up flares that exhibited high levels of polarization
and originated in the primary black hole jet. We propose that the
follow-up flares were induced as a result of accretion disk
perturbations, traveling from the site of impact towards the primary
SMBH. The timings inferred from our observations allowed us to estimate
the propagation speed of these perturbations. Additionally, we make
predictions for the future brightness of OJ 287.</p
Umbilical endometriosis: A case report
Introduction: Umbilical endometriosis is a rare disease with a prevalence of 0.5%-1%, which is more common at childbearing age in women. This condition normally presents as an over-6-cm mass, with localized symptoms and periodic pain in 81.5% of the cases. The symptoms include bleeding and inflammation.\ud
Methods: The present case report is about a rare disease, i.e. umbilical endometriosis, in a female patient.\ud
Results: The patient was a 35-year-old woman treated for five years’ history of endometriosis, and presenting to Imam Reza Hospital. She had suffered umbilical pain, enlargement and change of color for three months before presentation. Two weeks before presentation, she had also experienced bleeding from the umbilicus once and ultrasound ruled out umbilical hernia. She had a fairly echogenic 15*15 mm subcutaneous mass.\ud
Conclusion: Given the patient’s records and clinical history and the fact that umbilical bleeding is uncommon in adults, she was suspected to have an umbilical endometriosis and underwent surgery. The specimen sent for pathology also confirmed endometriosis.\u
In Vitro Fracture Resistance of Endodontically Treated Roots Filled with a Bonded Filling Material or Different Types of Posts
Aim: This study aimed to compare the fracture resistance of roots filled with a bonded material, fiber posts, or titanium post systems. Methods: Canals in the first group were filled with AH Plus and gutta-percha cones, and roots in the second group were filled with Epiphany sealer and Resilon cones. The root fillings (60 roots) were removed up to 4 mm from the canal apex to obtain 10-mm-deep post spaces, and posts were cemented. The groups were as follows: AH Plus control group, Epiphany control group, AH Plus fiber post group, AH Plus titanium post group, Epiphany fiber post group, and Epiphany titanium post group. Fracture tests were performed by using an lnstron testing machine. The force was applied at a 45 degrees axial angle with a constant speed of 1 mm/min. For each sample, the force at which fracture occurred was recorded in units of newtons. Statistical analysis was carried out by using analysis of variance test. Results: There was no statistically significant difference between all groups (P > .05). Conclusions: Titanium posts, fiber posts, and Epiphany root canal filling systems were found to have no reinforcing effect on endodontically treated roots
Effect of gaseous ozone and light-activated disinfection on the surface hardness of resin-based root canal sealers
Although root canal instruments remove most of the content from the main root canal space, disinfection or irrigation plays an indispensable role in all areas of the root canal system, especially in parts that are inaccessible by instruments. The originality of this study was to investigate the effect of two novel disinfection techniques on the surface hardness of resin-based endodontic sealers using atomic force microscopy (AFM). Forty extracted single-rooted maxillary central human teeth were prepared and divided into four groups according to treatment methods. The first group was irrigated with saline and served as a control, other groups irrigated with sodium hypochlorite (NaClO); gaseous ozone; and light-activated disinfection (LAD). The groups were divided into two subgroups, according to the obturation method used: subgroup A: gutta-percha and AH plus; and subgroup B: EndoREZ/resin-coated cones. After obturation, atomic force microscopy (AFM) measurement was performed to analyze the surface hardness of the sealers. There was a significant difference between group 1A and group 3A (p<0.05). Group 3B had the highest surface hardness values that were statistically different (p<0.05). When disregarding the sealers, the ozone possessed statistically higher surface hardness values than the other groups in all root thirds (p<0.05). The use of ozone and LAD may alter the surface hardness of resin-based sealers. The use of AFM can be considered an alternative hardness test techonology for sealing material. SCANNING 38:141-147, 2016. (c) 2015 Wiley Periodicals, Inc
In Vitro Fracture Resistance of Endodontically Treated Roots Filled with a Bonded Filling Material or Different Types of Posts
Aim: This study aimed to compare the fracture resistance of roots filled with a bonded material, fiber posts, or titanium post systems. Methods: Canals in the first group were filled with AH Plus and gutta-percha cones, and roots in the second group were filled with Epiphany sealer and Resilon cones. The root fillings (60 roots) were removed up to 4 mm from the canal apex to obtain 10-mm-deep post spaces, and posts were cemented. The groups were as follows: AH Plus control group, Epiphany control group, AH Plus fiber post group, AH Plus titanium post group, Epiphany fiber post group, and Epiphany titanium post group. Fracture tests were performed by using an lnstron testing machine. The force was applied at a 45 degrees axial angle with a constant speed of 1 mm/min. For each sample, the force at which fracture occurred was recorded in units of newtons. Statistical analysis was carried out by using analysis of variance test. Results: There was no statistically significant difference between all groups (P > .05). Conclusions: Titanium posts, fiber posts, and Epiphany root canal filling systems were found to have no reinforcing effect on endodontically treated roots
Can intra-coronally bleached teeth be bonded safely after antioxidant treatment?
The aim of this study was to compare the effects of antioxidant treatment and delayed bonding, following intra-coronal bleaching, on the shear bond strength (SBS) and bond failure site of brackets bonded to enamel. Eighty mandibular incisors were divided into four equal groups. After root canal filling, specimens in Group 1 were used as control and not bleached. For experimental groups 2 to 4, bleaching agent was placed into the rest of the cavity for a four-day period and this bleaching treatment was performed two times. In Group 2, specimens were bonded immediately after bleaching; in Group 3, specimens were bleached and then immersed in artificial saliva for 30 days before bonding; in Group 4, specimens were bleached, treated with an antioxidant agent, and then bonded. The SBS values of bonded brackets were measured in megapascal (MPa), while adhesive remnant index (ARI) scores were determined after the brackets failed. The SBS values of Group 1 (mean: 20.3 +/- 7.1 MPa) and Group 4 (mean: 18.2 +/- 6.1 MPa) were significantly higher (p>0.001) than those of Group 2 (mean: 4.9 +/- 3.2 MPa) and Group 3 (mean: 8.7 +/- 4.9 MPa). No significant differences in SBS were found between Groups 1 and 4, and between Groups 2 and 3
Neural Tube Defects in Jarcho-Levin Syndrome: Study of Twenty-Eight Cases
WOS: 000355932100001PubMed ID: 25792257Jarcho-Levin syndrome (JLS) is a congenital disorder consisting of various vertebral and costal anomalies. Congenital heart defects, abdominal wall malformations, urogenital and anal abnormalities, multiple skeletal anomalies, upper limb anomalies, spina bifida, and inguinal, umbilical and diaphragmatic hernias can be seen as components of JLS. Spina bifida appears to be a common finding in reported JLS cases. We retrospectively reviewed the medical records, plain Xrays and MRIs of patients with spina bifida between 2010 and 2014 and discussed the results. (C) 2015 S. Karger AG, Base