Effect of thermal cycling on micro-tensile bond strength of composite restorations bonded with multimode adhesive

Objective: The purpose of this in vitro study was to evaluate the effect of thermal cycling on the micro-tensile bond strength (Mtbs) of multimode adhesive agents. Materials and methods: Eight freshly extracted caries-free human third molars were used. The flat dentin surfaces were prepared and polished with 600-grit SiC abrasive paper for standard smear layer formation. The teeth were restored using Single Bond Universal Adhesive [(total etch (G1, G2)/self etch (G3, G4)]?+?Filtek Z550 and All-Bond Universal Adhesive [(total etch (G5, G6)/self etch (G7, G8)]?+?Aelite all-purpose. The specimens in groups G1, G3, G5, and G7 were subjected to thermal cycling (1000 cycles at 5–55 °C, for a 30?s dwell time), while the specimens in other groups were not exposed to an aging procedure. The Mtbs test was determined in all procedures. Data were submitted to three-way ANOVA and post hoc tests. The significance level was set at?=?0.05. Results: Group five was highly affected by the thermal cycling following the total etch procedure, while group one was not significantly affected. Group seven was highly affected by thermal cycling, while group three was not significantly affected after the self etch procedure. Group eight exhibited a higher mean Mtbs value after the thermal cycling procedure. Conclusion: The bond strength of multimode (universal) adhesives was found to be material dependent. The total etch procedure showed a higher Mtbs value than the self etch procedure.     

Parameters of color,transparency, water solubility,wettability and surface free energy of chitosan/hydroxypropylmethylcellulose (HPMC) films plasticized with sorbitol

This work examined the parameters of color, transparency, water solubility, wettability and surface free energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L?, a? and b? color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar surface free energy and the hydrophilic character when HPMC component was increased in the blend.     

The inhibitory effect of black pepper on formation of heterocyclic aromatic amines in high-fat meatball

The effect of black pepper on the formation of heterocyclic aromatic amines (HCAs) in high-fat meatball fried at three different frying temperatures (175 °C, 200 °C, and 225 °C) was investigated. The fried samples were analyzed for five HCAs, including 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP). In control group meatballs without black pepper, the total HCAs amount increased in parallel with the frying temperature increased. The highest total HCA amount was found 37.81 ng/g in control group meatballs fried at 225 °C, 31.80 ng/g of which belonged to PhIP accounting.  The reduction of black pepper on PhIP compound was 100%. On the perspective of total HCA amount, black pepper has an inhibitory effect (ranging from about 12 to 100%). MeIQx was not detected in any of chops samples.     

Rare loss-of-function mutation of a death receptor gene in head and neck cancer

The chromosomal region 8p21 contains a number of putative tumor suppressor genes and is a frequent site of translocations in head and neck cancers. Recently, a novel tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor gene, KILLER/DR5, a member of the tumor necrosis factor receptor family, was identified as a potential mediator in p53-dependent apoptosis and mapped to 8p21 by fluorescence in situ hybridization. We have determined the genomic structure of KILLER/DR5 and performed sequence analysis of all 10 coding exons in 20 primary head and neck cancers with allelic loss of chromosome 8p. To screen for a subset of mutations localized to the functional cytoplasmic death domain, we sequenced this region in an additional 40 primary head and neck cancers. We found two alterations in this domain, including a 2-bp insertion at a minimal repeat site, introducing a premature stop codon and resulting in a truncated protein. This KILLER/DR5 mutation was also present in the germ line of the affected patient, and the tumor did not have a p53 mutation by sequence analysis. Transfection studies in head and neck squamous cell carcinoma and colon and ovarian carcinoma cell lines revealed loss of growth-suppressive function associated with the tumor-derived KILLER/DR5 truncation mutant. These observations provide the first evidence for mutation of a TRAIL death receptor gene in a human cancer, leading to loss of its apoptotic function.     

Late posterior cardiac tamponade after open heart surgery

OBJECTIVE: Late cardiac tamponade after open heart surgery is a relatively uncommon, but potentially serious complication. We retrospectively analyzed 14 patients who had posterior cardiac tamponade 13 to 210 days after open heart surgery. PATIENTS: Between May 1988 and July 1995, 3150 adult patients underwent open heart surgery at the Gülhane Military Medical Academy. In 35 of 3150 patients (1.11%) late pericardial effusions developed, and in 14 (0.44% of 3150 consecutive open heart surgery performed on adult patients in our center) of these patients had posterior tamponade. There were moderate symptoms including fatigue, malaise, and dyspnea on exertion in all patients. The diagnosis was made by echocardiography in 13 patients, and by tomographic scanning in 1 patient. Analysis of these 14 patients revealed that all of them had hemodynamic criteria consistent with tamponade physiology on right heart catheterization with Swan-Ganz catheters. RESULTS: Echocardiography guid pericardiocentesis through the left anterior axillary line was effective in decompressing of posterior cardiac tamponade in 10 of 14 patients. Three patients required operative surgical drainage after unsuccessful pericardiocentesis through subxiphoid area. Two patients who underwent surgical drainage died, and in one patient surgical pericardiotomy had complete evacuation of posterior pericardial fluid with major complication. CONCLUSIONS: 2-D echocardiography guid pericardiocentesis through left anterior axillary line was found to be a useful, safe, and simple technique. It can be used as an alternative treatment to surgical pericardiotomy for posterior cardiac tamponade after open heart surgery.     

Mother-Infant Interactions in Rats Lacking CCKA Receptors.

Mediation of mother-infant interactions by the brain-gut peptide cholecystokinin (CCK) was examined by observing behavior of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which lack functional CCKA receptors because of a genetic abnormality. OLETF (n = 10) and control (Long-Evans Tokushima Otsuka [LETO] n = 10) dams interacted with 1 pup of each line on Postpartum Days 6-9. OLETF pups received more body and anogenital licking and emitted substantially more ultrasonic vocalizations than LETO pups. OLETF dams carried pups less frequently and showed a nursing position more frequently than LETO dams. No significant Pup X Dam Line interactions or line differences in dams' activity were detected. The results provide convergent validity to previous pharmacological studies implicating CCK mediation of both infant and maternal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Appendectomy in the surgical staging of ovarian carcinoma

The CAMP reaction between Listeria monocytogenes and Rhodococcus equi was studied by a diffusion assay. Listeria monocytogenes displayed identical cooperative haemolytic effect with supernatant cultures of R. equi or with commercial cholesterol oxidase (COX). This result, even with enzymes of different sources (commercial COX is obtained from Pseudomonas spp.) suggests that this enzyme secreted by R. equi has a crucial role in the synergistic haemolytic (CAMP) reaction with L. monocytogenes. The mechanism of the cooperative lytic process between L. monocytogenes and R. equi may represent a different and novel mechanism reaction, in which the COX may not act as a conventional second-step factor, and a reaction different to the direct interaction with the cholesterol of the erythrocyte membrane may be involved.     

Correlation dimension estimation: can this nonlinear description contribute to the characterization of blood pressure control in rats?

The application of correlation dimension estimation to the study of cardiovascular control, via the blood pressure (BP) time series was investigated. We chose to calculate the Grassberger-Procaccia (GP) correlation dimension. In order to obtain a reliable estimate of the correlation dimension, we studied impact of various parameters such as the appropriate sampling rate, the time delays, the embedding dimension, the minimal trace length required, and the number of points needed as reference points. We developed a recipe for the reliable treatment of the continuous BP signal in rats, our animal model, and discussed the possible pitfalls which demand special attention. Next, we applied the surrogate data method to a BP time series, looking for the existence of nonlinear components, in order to test whether the nonlinear modeling is necessary for accurately describing the system. We found that, indeed, the correlation dimension does reveal information which cannot be unveiled by the commonly used power spectral technique, thus, making the nonlinear modeling an important approach, providing additional insight into the cardiovascular control system.     

Degeneration of mechanical characteristics and performances with Zr nanoparticles inserted in Bi-2223 superconducting matrix and increment in dislocation movement and cracks propagation

This study explains the role of Zr concentration level on mechanical characteristics and performance belonging to the bulk Bi-2223 superconducting materials by means of standard Vickers microhardness (H _v ) measurements at different applied loads in the range of 0.245–2.940 N and evaluated theoretical calculations. The experimental measurement results obtained display that the mechanical performances regress with the increment of the Zr addition level due to the increased artificial disorders/damages/breaks/voids/cracks and irregular grain orientation distribution. In other words, the Zr addition accelerates both the dislocation movement and especially the cracks/voids propagation of as a consequence of the decrement in the Griffith critical crack length, being one of the most striking points deduced from this work. These vital findings are also favored by the extracted parameters of Young’s modulus, yield strength, fracture toughness and brittleness index. Nevertheless, it is found that every sample studied exhibit typical indentation size effect (ISE) behavior due to the production of the elastic and plastic deformations simultaneously in the system. Moreover, the load dependent microhardness values are theoretically analyzed with the aid of six available models such as six available approaches: Meyer’s law, proportional sample resistance model, modified proportional sample resistance model, elastic/plastic deformation, Hays–Kendall (HK) and indentation-induced cracking model for the first time. The results obtained show that the HK approach exhibits perfectly performance on the analysis of the mechanical characteristics of the superconducting materials exhibiting ISE behavior whereas the other models are inadequate to explain the load independent mechanical characteristics of the Bi-2223 system added by the Zr nanoparticles.