Marginal integrity of low-shrinkage and methacrylate-based composite resins: Effect of three different hemostatic agents

Background: Moisture control is very important in restorative procedures in dentistry. Use of hemostatic agents helps control moisture; however, they might result in changes on enamel and dentin surfaces, affecting composite resin bond quality. The aim of this in vitro study was to evaluate the marginal microleakage of two different composite resins with the use of three different hemostatic agents. Material and Methods: Standardized Class V cavities were prepared on the buccal and lingual surfaces of 48 premolars with cervical margins 1 mm apical to the cementoenamel junction (CEJ). The samples were randomly divided into 8 groups. In groups 1 to 4, an etch-and-rinse adhesive (Adper Single Bond) was applied as the bonding system, followed by exposure to different hemostatic agent: group 1: no hemostatic agent (control); group 2: ViscoStat; group 3: ViscoStat Clear; and group 4: trichloracetic acid, as hemostatic agents. The cavities were restored with Z-250 composite resin. In group 5 to 8 Silorane System Adhesive (Filtek P90 Adhesive) was applied as a bonding agent, followed by exposure to different hemostatic agents in a manner similar to that in groups 1to 4. The cavities were restored with Filtek P90, a low-shrinkage composite resin. The samples in each group were evaluated for dye penetration under a stereomicroscope at ×36 after 24 hours and a 500-round thermocycling procedure at enamel and dentin margins. Statistical analysis was carried out using Kruskal-Wallis and Mann-Whitney tests (α=0.05). Results: Z-250 composite resin exhibited significantly higher dentin microleakage scores compared to Filtek P90 (P = 0.004). Trichloracetic acid increased dentin microleakage with Filtek P90 (P=0.033). Conclusions: Under the limitations of this in vitro study, application of hemostatic agents did not affect microleakage of the two tested composite resins except for trichloracetic acid that increased marginal microleakage when used with Filtek P90. © Medicina Oral

Analysis of Mixed Correlated Bivariate Negative Binomial and Continuous Responses

A general model for the mixed correlated negative binomial and continuous responses is proposed. It is shown how to construct parameter of the models, using the maximization of the full likelihood. Influence of a small perturbation of correlation parameter of the model on the likelihood displacement is also studied. The model is applied to a medical data, obtained from an observational study on women, where the correlated responses are the negative binomial response of joint damage and continuous responses of body mass index. Simultaneous effects of some covariates on both responses are investigated

Unusual Behaviour of an Earth-Rockhill Dam

The post-construction behaviour of a 47.5 m high and 700 m long earth-rockfill dam, located in northwestern Iran, is described. The embankment dam is founded on Tertiary rock on both abutments, but in the river channel it rests on alluvial deposits of variable composition and thickness. Since the first impoundment, the dam has undergone large deformations, both in vertical and in horizontal directions. These have resulted in unusual differential settlements, visible along the crest, and have produced wide longitudinal cracks in the asphalt pavement of the crest road. The principle features of the dam are described and selected monitoring results of the crest movements for a sixteen year period are presented. Based on the analysis of the available data and taking into account the geotechnical characteristics of the foundation and the fill materials, an interpretation of the unusual behaviour has been attempted

Determination of LC50 of copper in Litopenaeus vannamei

We determined the LC50 of copper (as CUSO_4) and it's Maximum Allowable Concentration (MAC) for Litopenaeus vannamei. The study was performed in 2003 for which bioassays were used for acute toxicity tests in a period of 96 hours during which water parameters such as water temperature, pH, dissolved oxygen, hardness, alkalinity were also measured. Ten treatments and three replicates for each treatment were used. A LC50 of 86.71, 27.28, 7.98 and 3.90mg/1 and also Maximum Allowable Concentration of 8.671, 2.728, 0.798 and 0.390mg/1 were determined at 24, 48, 72 and 96 hours post exposure. Results showed that L. vannamei is relatively resistant to copper. Hence, short period application of copper to white shrimp farms for controlling algal bloom is judged harmless to the fish

An innovative framework for real-time monitoring of pollutant point sources in river networks

Simultaneous identification of the location and release history of pollutant sources in river networks is an ill-posed and complicated problem, particularly in the case of multiple sources with time-varying release patterns. This study presents an innovative method for solving this problem using minimum observational data. To do so, a procedure is proposed in which, the number and the suspected reaches to the existence of pollutant sources are determined. This is done by defining two different types of monitoring stations with an adaptive arrangement in addition to real-time data collection and reliable flow and transport mathematical models. In the next step, the sources’ location and their release history are identified by solving the inverse source problem employing a geostatistical approach. Different scenarios are discussed for different conditions of number, release history and location of pollutant sources in the river network. Results indicated the capability of the proposed method in identifying the characteristics of the sources in complicated cases. Hence, it can be effectively used for the comprehensive monitoring of river networks for different purposes

Effect of Surgical Flap on IL-1β and TGF-β Concentrations in the Gingival Crevicular Fluid of Patients with Moderate to Severe Chronic Periodontitis

Background: Growth factors play a major part in wound healing in many tissues including the periodontium. Transforming growth factor-β1 (TGF-β1) is one of these factors present in the gingival crevicular fluid. In addition, it is considered as one of the most important anti-inflammatory cytokines. Interleukin-1β is a proinflammatory cytokine that presents itself in gingival inflammation and the GCF. Such factors might be of value as prognostic markers of wound healing activity and the therapeutic progress following flap surgery. Objective: The aim of this study was to evaluate the effect of surgical flap on the concentration of IL-1β and TGF-β in the GCF of patients with moderate to severe chronic periodontitis. Methods: The GCF samples were collected, using the Perio-Paper strip at phase 1 (pre-surgery), phase 2 (4th week post surgery) and phase 3 (12th week post surgery) from 20 sites of 10 patients undergoing flap surgery. After the elution, IL-1β and TGF-β concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Results: The mean TGF-β and IL-1β concentration decreased from phase 1 to phase 3 (p<0.05). There were no significant statistical correlations between IL-1β and TGF-β1 concentrations in the 3 assessment phases. There was a significant statistical correlation between TGF-β1 concentrations and the Plaque Index (PI) in phase 2 (p<0.05). There was a significant statistical correlation (p<0.05) between IL-1β and TGF-β1 concentration and the probing pocket depth (PPD). Conclusion: The flap surgery has a significant effect on decreasing IL-1β concentration. In the case of TGF-β1, probably the decrease in the concentration after treatment might be due to the removal of the inflammatory stimulants

N-fold Supersymmetry in Quantum Systems with Position-dependent Mass

We formulate the framework of N-fold supersymmetry in one-body quantum mechanical systems with position-dependent mass (PDM). We show that some of the significant properties in the constant-mass case such as the equivalence to weak quasi-solvability also hold in the PDM case. We develop a systematic algorithm for constructing an N-fold supersymmetric PDM system. We apply it to obtain type A N-fold supersymmetry in the case of PDM, which is characterized by the so-called type A monomial space. The complete classification and general form of effective potentials for type A N-fold supersymmetry in the PDM case are given.Comment: 18 pages, no figures; Refs. updated, typos correcte