Analysis Of Debris From Implant Prostheses

Objectives: The specific aim of this study was to analyze any entrapped debris in implant abutment screw threads from post processed constructs from dental laboratories. Materials and Methods: Forty implant screws were used to collect debris where screws were removed from the implant prosthesis as received from dental laboratories. In all samples, laboratory procedures including fabrication of the custom abutment, definitive prosthesis and finishing/polishing were completed prior to sampling. Twenty-nine screws were from titanium and eleven screws were from zirconia abutments. Scanning Electron Microscope (SEM) analyses of collected particulate products from abutment screws were done for all specimens. Results: The SEM analysis showed multiple particles with different sizes, shapes and chemistries. Elemental analysis of these particles supported that their origin was from the abutment/prosthesis or transferred from other sources utilized in the dental laboratories during the fabrication processes. Conclusion: Based on the results it was concluded that particles on abutment screw surface were present and their characteristics may affect the abutment implant joint stability and/or may have a biological effect on peri-implant tissue health. Therefore a consistent method of cleaning is needed for abutment screws before clinical use of any screw and prosthesis received after processing by dental laboratories

Forecasting seat sales in passenger airlines: introducing the round-trip model

This thesis aims to improve sales forecasting in the context of passenger airlines. We study two important issues that could potentially improve forecasting accuracy: day-to-day price change rather than price itself, and linking flights that are likely to be considered as pairs for a round trip by passengers; we refer to the latter as the Round-Trip Model (RTM). We find that price change is a significant variable regardless of days remaining to flight in the last three weeks to flight departure, which opens the possibility of planning for revenue maximizing price change patterns. We also find that the RTM can improve the precision of the forecasting models, and provide an improved pricing strategy for planners. In the study of the effect of price change on sales, analysis of variance is applied; finite regression mixture models were tested to identify linked traffic in the two directions and the linked flights on a route in reverse directions; adaptive neuro-fuzzy inference system (ANFIS) is applied to develop comparative models for studying sales effect between price and price change, and one-way versus round-trip models. The price change model demonstrated more robust results with comparable estimation errors, and the concept model for the round-trip with only one linked flight reduced estimation error by 5%. This empirical study is performed on a database with 22,900 flights which was obtained from a major North American passenger airline

A novel case of TIF1 gamma autoantibody positive dermatomyositis associated with a non-functional pancreatic neuroendocrine tumor

Dermatomyositis (DM) is an idiopathic inflammatory myopathy characterized by proximal muscle weakness associated with a distinct cutaneous eruption. The association of DM with malignancy has been extensively described in the literature. Patients with DM that also have transcriptional intermediary factor

Theoretical and Experimental Investigation of Switch-Like Responses Arising from Multisite Protein Phosphorylation.

Switch-like responses are important regulatory features of biological processes involving binary decisions such as cell division. Multisite protein phosphorylation is a proposed mechanism for achieving switch-like behaviors. For example, it is conjectured that the G1/S transition of the yeast cell cycle occurs in a switch-like fashion due to multisite phosphorylation-triggered degradation of the Sic1 protein. The objective of this dissertation is first to acquire a quantitative and predictive understanding of switch-like behaviors arising from multisite phosphorylation in natural systems, and second to employ this knowledge for the design of synthetic protein devices. We first developed a mathematical model to investigate systematically the role of multisite phosphorylation in the phosphorylation-triggered degradation process of a protein like Sic1. We found that as the number of sites increases, a more switch-like temporal profile can be generated. The steepness is determined synergistically by various factors, including the total number of sites and kinetic parameters. To test our theoretical predictions, we examined the steady-state response of wild-type and mutant Sic1 with various numbers of phosphorylation sites. It was observed that the response of Sic1, measured by its binding to a downstream protein Cdc4 in the degradation pathway, to the Cln2-Cdc28 kinase in vitro is switch-like. Furthermore, the ultrasensitivity decreases as the number of sites decreases. We next showed, through computational analysis, that a multisite protein can exhibit sustainable and tunable oscillations when embedded in a negative feedback loop, formed via inhibition of the rst phosphorylation step. We also designed a protein degradation device based on multiple protein binding domains and carried out preliminary study of its implementation. Our work demonstrates the potential of utilizing multisite proteins or the broader design principle of intramolecular multiple interaction modules, which provides an effective and flexible means for generating high nonlinearity, in creating a wide range of synthetic biological devices. This dissertation suggests quantitative design principles for switch-like stimulusresponse relationships arising from multisite protein phosphorylation, which might be a widespread mechanism in cellular regulation. In addition, our results provide intriguing hypotheses to be investigated experimentally in future work, such as the critical effect of multi-step phosphorylation kinetics.Ph.D.Chemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/89620/1/varedi_1.pd

A comprehensive survey of the analytical, numerical and experimental methodologies for dynamics of multibody mechanical systems with clearance or imperfect joints

"Available online 19 December 2017"A comprehensive survey of the literature of the most relevant analytical, numerical, and experimental approaches for the kinematic and dynamic analyses of multibody mechanical systems with clearance joints is presented in this review. Both dry and lubricated clearance joints are addressed here, and an effort is made to include a large number of research works in this particular field, which have been published since the 1960′s. First, the most frequently utilized methods for modeling planar and spatial multibody mechanical systems with clearance joints are analyzed, and compared. Other important phenomena commonly associated with clearance joint models, such as wear, non-smooth behavior, optimization and control, chaos, and uncertainty and links’ flexibility, are then discussed. The main assumptions procedures and conclusions for the different methodologies are also examined and compared. Finally, future developments and new applications of clearance joint modeling and analysis are highlighted.This research was supported in part by the China 111 Project (B16003) and the National Natural Science Foundation of China under Grants 11290151, 11472042 and 11221202. The work was also supported by the Portuguese Foundation for Science and Technology with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio