In silico modelling of aortic valve implants - predicting in vitro performance using finite element analysis.

The competing structural and hemodynamic considerations in valve design generally require a large amount of in vitro hydrodynamic and durability testing during development, often resulting in inefficient "trial-and-error" prototyping. While in silico modelling through finite element analysis (FEA) has been widely used to inform valve design by optimising structural performance, few studies have exploited the potential insight FEA could provide into critical hemodynamic performance characteristics of the valve. The objective of this study is to demonstrate the potential of FEA to predict the hydrodynamic performance of tri-leaflet aortic valve implants obtained during development through in vitro testing. Several variations of tri-leaflet aortic valves were designed and manufactured using a synthetic polymer and hydrodynamic testing carried out using a pulsatile flow rig according to ISO 5840, with bulk hydrodynamic parameters measured. In silico models were developed in tandem and suitable surrogate measures were investigated as predictors of the hydrodynamic parameters. Through regression analysis, the in silico parameters of leaflet coaptation area, geometric orifice area and opening pressure were found to be suitable indicators of experimental in vitro hydrodynamic parameters: regurgitant fraction, effective orifice area and transvalvular pressure drop performance, respectively.

Haplotype analysis for Irish ancestry.

Forensic haplotype analysis of the male Y chromosome is currently used to establish the number of male donors in sexual assaults, the number of male bleeders in blood pattern analysis, and for ancestry correlation to genetic founder populations in biogeographic studies. In forensic laboratory applications, its primary use is for DNA profile generation with trace amounts of male DNA in the presence of excess female DNA (e.g. spermatozoa identification, male component of fingernail scrapings). Our study supports the potential use of the Y chromosome in a "dragnet" approach (most haplotypes are unique) similar to that described by Kayser in 2017 for solving a cold case sex assault and homicide in The Netherlands. Our study also researched the potential for the identification of an ancestral Irish genetic "footprint" linked to surname O'Brien and identified multiple founder group origins in Ireland and England as well as three samples with the Dal Riata (a Gaelic overkingdom) ancestral haplotype. This study indicates correlation to ancestral Irish ancestry by haplotype but not conclusively to the O'Brien surname.

Evaluation of a telephone advice system for remote intravenous thrombolysis in ischemic stroke: data from a United kingdom network.

BACKGROUND AND PURPOSE: There is limited evidence for remote stroke thrombolysis using telephone consultation and teleradiology. Results from a UK network using this treatment model are presented. METHODS: Retrospective study of consecutive patients thrombolysed in 5 hospitals, with well organized stroke services, between 2012 and 2013. Remote thrombolysis was compared with thrombolysis delivered in person for symptomatic intracerebral hemorrhage, death within 7 days, and 90-day modified Rankin scores. RESULTS: Of 586 patients, 220 (37.5%) were thrombolysed remotely. The 2 groups were well matched (median age 77 years, NIHSS 12). Remote thrombolysis increased treatment time by 22 minutes. Outcomes were no different in the 2 groups (remote versus standard): symptomatic intracerebral hemorrhage (3.6% versus 4.6%), death within 7 days (6.4% versus 7.1%), modified Rankin score <2 (46.0% versus 46.1%), and modified Rankin score 6 (15% versus 17.5%) at 90 days. CONCLUSION: Telephone advice and teleradiology, within an organized system of care, can be an effective method of delivery of intravenous thrombolysis.

In vitro evaluation of the retention of zirconia-based ceramic posts luted with glass ionomer and resin cements

Este estudo avaliou a retenção de pinos intra-radiculares cerâmicos à base de zircônia (CosmoPost system) fixados com cimento de ionômero de vidro ou resinoso. Trinta e dois dentes extraídos, livres de cárie e não-restaurados foram selecionados e armazenados em solução de clorexidina e água. Os dentes foram submetidos a tratamento endodôntico e distribuídos aleatoriamente em dois grupos (n=16). Cada dente teve a coroa removida e um espaço protético de 1.0 mm de profundidade (medida a partir da superfície radicular) foi preparado para receber um pino de dióxido de zircônio com 1,4 mm de diâmetro. Cada grupo teve os pinos fixados com cimento de ionômero de vidro (Fuji I) ou cimento resinoso (Variolink II). Os conjuntos dente/pino foram incluídos em blocos de resina e submetidos a testes de tração. Foi utilizado um tensiômetro para registrar a força de tração necessária para deslocar os pinos cimentados. Os valores médios de tração de ambos os grupos foram analisados por ANOVA e pelo teste t de Student. O nível de significância foi fixado em 5%. Foram obtidos os seguintes valores médios de tensão de ruptura (N) e desvios-padrão: Fuji I = 121,8 (±17,4); Variolink II = 228,1 (±36,8). Os pinos fixados com cimento resinoso apresentaram maior resistência ao deslocamento do que aqueles fixados com cimento de ionômero de vidro, sendo esta diferença estatisticamente significante (p<0,05). Pode-se concluir que os pinos de zircônia cimentados com cimento resinoso (Variolink II) apresentaram falhas sob valores de tensão significativamente maiores que os registrados para os pinos cimentados com ionômero de vidro (Fuji I). Independente do tipo de cimento utilizado, os pinos apresentaram falhas adesivas na interface cimento/pino ao serem submetidos a esforços de tensão.

In vitro evaluation of the retention of zirconia-based ceramic posts luted with glass ionomer and resin cements

The retention of zirconia-based ceramic posts (CosmoPost system) luted with glass ionomer and resin cements was evaluated. Thirty two extracted, caries-free, unrestored teeth were selected and stored in chlorhexidine and water solution. The teeth were endodontically treated and randomly assigned to two groups (n=16). Each tooth was decoronated and prepared to a depth of 10.0 mm from root surfaceto receive a 1.4 mm diameter zirconium dioxide post. Each group had posts cemented with either glass ionomer cement (Fuji I) or resin cement (Variolink II). The post/teeth specimens were embedded in resin blocks and subjected to tensile testing. The tensile force required to dislodge the cemented posts in a tensile testing machine was recorded. The mean stress values of both groups were analyzed for statistical differences using ANOVA and Student’s t-test. Significance level was set at 5 percent. Mean peak forces at failure (N) and standard deviation for the tested cements were the following: Fuji I = 121.8 (plus or minus 17.4) and Variolink II = 228.1 (plus or minus 36.8). Posts luted with the resin cement presented statistically significant higher tensile bond strength than those retained with glass ionomer (p<0.05). It may be concluded that zirconia posts cemented with resin-based cement (Variolink II) failed at statistically significant higher valuescompared to those cemented with glass ionomer cement (Fuji I). Regardless of the cement type, the posts failed adhesively at the cement/post interface when subjected to a tensile force.

In vitro evaluation of the retention of zirconia-based ceramic posts luted with glass ionomer and resin cements.

The retention of zirconia-based ceramic posts (CosmoPost system) luted with glass ionomer and resin cements was evaluated. Thirty-two extracted, caries-free, unrestored teeth were selected and stored in chlorhexidine and water solution. The teeth were endodontically treated and randomly assigned to two groups (n=16). Each tooth was decoronated and prepared to a depth of 10.0 mm from root surface to receive a 1.4 mm diameter zirconium dioxide post. Each group had posts cemented with either glass ionomer cement (Fuji I) or resin cement (Variolink II). The post/teeth specimens were embedded in resin blocks and subjected to tensile testing. The tensile force required to dislodge the cemented posts in a tensile testing machine was recorded. The mean stress values of both groups were analyzed for statistical differences using ANOVA and Student's t-test. Significance level was set at 5%. Mean peak forces at failure (N) and standard deviation for the tested cements were the following: Fuji I = 121.8 (+/-17.4) and Variolink II = 228.1 (+/-36.8). Posts luted with the resin cement presented statistically significant higher tensile bond strength than those retained with glass ionomer (p<0.05). It may be concluded that zirconia posts cemented with resin-based cement (Variolink II) failed at statistically significant higher values compared to those cemented with glass ionomer cement (Fuji I). Regardless of the cement type, the posts failed adhesively at the cement/post interface when subjected to a tensile force.