A comparative study of physicochemical properties of AH Plus, Epiphany, and Epiphany SE root canal sealers

P>Aim To assess the physicochemical properties and the surface morphology of AH Plus, Epiphany, and Epiphany SE root canal sealers. Methodology Five samples of each material were employed for each test according to ANSI/ADA specification 57. The samples were assigned to four groups: (i) AH Plus; (ii) Epiphany; (iii) Epiphany + Thinning Resin; (iv) Epiphany SE. The distilled water used during the solubility test was submitted to spectrometry to verify the release of calcium ions. The morphologies of the external surface and the cross-section of the samples were analysed by means of a scanning electron microscope (SEM). Statistical analysis was performed by using One-Way anova and post hoc Tukey-Kramer tests with the null hypothesis set as 5%. Results Setting time, flow and radiopacity results were in accordance with ANSI/ADA requirements whereas the dimensional change of all sealers and solubility of Epiphany did not fulfil ANSI/ADA protocols. AH Plus and Epiphany SE were similar in terms of flow, radiopacity, solubility and dimensional change. The spectrometry test revealed significant calcium ion release from Epiphany with and without the thinning resin. SEM analysis revealed essentially a homogeneous surface with compact layer and some rough areas. Conclusions Setting time, flow, and radiopacity tests conformed to ANSI/ADA standardization. The dimensional change in all groups and the solubility of Epiphany were greater than values considered acceptable, with higher amounts of calcium ion release. Epiphany SE revealed more organized, compacted, and homogeneous polymers in a reduced resin matrix when compared with the other groups.

Microleakage into and from Two-Stage Implants: An In Vitro Comparative Study

Purpose: Gaps between an abutment and a dental implant are unavoidable, and microleakage may occur, leading to problems such as malodor and peri-implantitis. The aim of the present in vitro study was to investigate leakage of Staphylococcus aureus through the implant/abutment interface by the method of bacterial culture, and to compare the leakage rates of two different types of implant-abutment connections. Materials and Methods: Twenty Morse taper implants with abutments were divided into two groups: group A, which were evaluated for microleakage into the inner part of the implants, and group B, which were evaluated for microleakage from the inner part of the implants. Twenty internal-hexagon implants with abutments were also divided into two groups: group C, which were evaluated for microleakage into the inner part of the implants, and group D, which were evaluated for microleakage from the inner part of the implants. For the evaluation of leakage from the implants, the assemblies had the inner parts inoculated with S aureus, and each assembly was incubated in sterile brain heart infusion broth for 1 week. For assessment of leakage into the implants, each assembly was submerged in 4 mL S aureus culture in tubes and incubated for 2 weeks. The microleakage of the two implant connections was compared. Results: Microbial leakage occurred in all groups, and there was no statistically significant difference between groups A and C or between groups B and D. Conclusions: In vitro, S aureus leakage through the implant/abutment interface occurred with both Morse taper and internal-hexagon implants. INT J ORAL MAXILLOFAC IMPLANTS 2011;26:56-62

Cultural aspects of classroom effectiveness: Overseas-educated students in Australian classrooms

Teachers who are new to the country often find themselves as 'the stranger' in their own classroom. Languages education is one area where such overseas-educated teachers are common. The study reported here investigated what cultural factors might influence the classroom performance of such teachers. The early classroom experience of beginning Japanese native speaker teachers and trainees was examined to this end.

A comparative study of the radiation resistance of four optically transparent polyimides

A comparative study of the high energy radiation resistance to formation of radicals in two pairs of polymers is reported. In one pair of polymers the phenyl groups containing the imide rings are separated by an ether linkage and in the other pair they are separated by an hexafluoroisopropylidine group. Two of the polymers contained aromatic amine units linked through an ether linkage and the other two polymers contained a trifluoromethyl biphenyl diamine. The polymers were shown to retain a high level of transparency in the visible region following radiolysis to doses as high as 8 Gy. ESR studies of the resistance to radical formation on radiolysis. at 77 K revealed that the polymers containing ether linkages were more stable than their fluorinated analogues, but all were less stable than Kapton (R). (C) 2001 Elsevier Science Ltd. All rights reserved.

The pyramidal cell in cognition: A comparative study in human and monkey

Here we present evidence that the pyramidal cell phenotype varies markedly in the cortex of different anthropoid species. Regional and species differences in the size of, number of bifurcations in, and spine density of the basal dendritic arbors cannot be explained by brain size. Instead, pyramidal cell morphology appears to accord with the specialized cortical function these cells perform. Cells in the prefrontal cortex of humans are more branched and more spinous than those in the temporal and occipital lobes. Moreover, cells in the prefrontal cortex of humans are more branched and more spinous than those in the prefrontal cortex of macaque and marmoset monkeys. These results suggest that highly spinous, compartmentalized, pyramidal cells (and the circuits they form) are required to perform complex cortical functions such as comprehension, perception, and planning.

Dendritic branching patterns of pyramidal cells in the visual cortex of the new world marmoset monkey, with comparative notes on the old world macaque monkey

The basal dendritic arbors of 442 supragranular pyramidal cells in visual cortex of the marmoset monkey were compared by fractal analyses. As detailed in a previous study,(1) individual cells were injected with Lucifer Yellow and processed for a DAB reaction product. The basal dendritic arbors were drawn, in the tangential plane, and the fractal dimension (D) determined by the dilation method. The fractal dimensions were compared between cells in ten cortical areas containing cells involved in visual processing, including the primary visual area (Vi), the second visual area (V2), the dorsoanterior area (DA), the dorsomedial area (DM), the dorsolateral. area (DL), the middle temporal area (MT), the posterior parietal area (PP), the fundus of the superior temporal area (FST) and the caudal and rostral subdivisions of inferotemporal cortex (ITc and ITr, respectively). Of 45 pairwise interareal comparisons of the fractal dimension of neurones, 20 were significantly different. Moreover, comparison of data according to previously published visual processing pathways revealed a trend for cells with greater fractal dimensions in higher cortical areas. Comparison of the present results with those in homologous cortical areas in the macaque monkey(2) revealed some similarities between the two species. The similarity in the trends of D values of cells in both species may reflect developmental features which, result in different functional attributes.

Standardizing assessment of adverse effects in rheumatology clinical trials. Status of OMERACT Toxicity Working Group March 2000: Towards a common understanding of comparative toxicity/safety profiles for antirheumatic therapies

This paper describes the background and current status of an OMERACT facilitated effort to improve the consistency of adverse event reporting in rheumatology clinical trials, The overall goal is the development of an adverse event assessment tool that would provide a basis for use of common terminology and improve the consistency of reporting severity of side effects within rheumatology clinical trials and during postmarketing surveillance. The resulting Rheumatology Common Toxicity Criteria Index encompassed the following organ systems: allergic/immunologic, cardiac, ENT, gastrointestinal, musculoskeletal, neuropsychiatric, ophthalmologic, pulmonary and skin/integument. Before this tool is widely accepted, its validity, consistency, and feasibility need to be assessed in clinical trials.

Pectenotoxins - an issue for public health - A review of their comparative toxicology and metabolism

Pectenotoxins (PTXs) are a group of toxins associated with diarrhetic shellfish poisoning (DSP) and isolated from DSP toxin-producing dinoflagellate algae. Consumption of shellfish contaminated with PTXs has been associated with incidences of severe diarrhetic illness resulting in hospitalisation. Concern has been raised for public health following the discovery that these toxins are not only hepatotoxic and can cause diarrhetic effects in mammals, but that they are potently cytotoxic to human cancer cell lines and have been found to be tumour promoters in animals. With advances in knowledge and technology, more PTXs are being identified, but little is known of their toxicology and the potential impact these toxins may have on public health in the long term. Without such information, adequate health-risk assessments for the consumption of shellfish contaminated with PTXs cannot be performed. This review gives a brief introduction to diarrhetic shellfish toxins, details the known toxicology and metabolism of PTXs in animals, and discusses known incidences of PTX poisoning in humans. (C) 2001 Elsevier Science Ltd. All rights reserved.

Factors influencing job valuation: a comparative study of critical care and mon-critical care nurses

This study sought to identify the relationship between three predictor variables. perceived collaboration with medical staff, autonomy and independent actions and an outcome. the value hospital nurses placed on their work. In total 189 critical care and 366 non-critical care nurses completed a mailed survey. Critical cure nurses perceived themselves to have a mure collaborative relationship with the medical staff. described performing actions independent of medical orders more frequently and perceived their jobs to have more value than non-critical care nurses. However the latter group perceived themselves to have more autonomy in their work. Within both groups collaboration and autonomy were significantly, but weak to moderately correlated with job valuation. Simply expanding the work hospital nurses do is unlikely to result in nurses valuing their jobs more. however promoting an environment of respect and sharing between the medical and nursing staff and supporting nurses when they act in an autonomous fashion may positively influence nurses' perceptions of their work. (C) 2001 Elsevier Science Ltd. All rights reserved.