Lifetime assessment of electronic components for high reliability aerospace applications

This paper details a modelling approach for assessing the in-service (field) reliability and thermal fatigue life-time of electronic package interconnects for components used in the assembly of an aerospace system. The Finite Element slice model of a Plastic Ball Grid Array (PBGA) package and suitable energy based damage models for crack length predictions are used in this study. Thermal fatigue damage induced in tin-lead solder joints are investigated by simulating the crack growth process under a set of prescribed field temperature profiles that cover the period of operational life. The overall crack length in the solder joint for all different thermal profiles and number of cycles for each profile is predicted using a superposition technique. The effect of using an underfill is also presented. A procedure for verifying the field lifetime predictions for the electronic package by using reliability assessment under Accelerated Thermal Cycle (ATC) testing is also briefly outlined.

Differential lifetime success and performance of native and non-native Atlantic salmon examined under communal natural conditions.

The lifetime success and performance characteristics of communally reared offspring of wild native Burrishoole (native), ranched native (ranched) and non-native (non-native) Atlantic salmon Salmo salar from the adjacent Owenmore River were compared. Non-native year parr showed a substantial downstream migration, which was not shown by native and ranched parr. This appears to have been an active migration rather than competitive displacement and may reflect an adaptation to environmental or physiographic conditions within the Owenmore River catchment where the main nursery habitat is downstream of the spawning area. There were no differences between native and ranched in smolt output or adult return. Both of these measures, however, were significantly lower for the non-native group. A greater proportion of the non-native Atlantic salmon was taken in the coastal drift nets compared to the return to the Burrishoole system, probably as a result of the greater size of the non-native fish. The overall lifetime success of the non-native group, from fertilized egg to returning adult, was some 35% of native and ranched. The ranched group showed a significantly greater male parr maturity, a greater proportion of 1+ year smolts, and differences in sex ratio and timing of freshwater entry of returning adults compared to native, which may have fitness implications under specific conditions.

The Unexpected Preference for the fac-Isomer with the Tris(5-ester-substituted-2,2′-bipyridine) Complexes of Ruthenium(II)

The synthesis of a number of new 2,2'-bipyridine ligands, functionalized with bulky ester side groups is reported (L2 - L8). Their reaction with [Ru(DMSO)4Cl2] gives rise to tris-chelate ruthenium(II) metal complexes which show an unusually high proportion of the fac-isomer, as judged by 1H NMR following conversion to the ruthenium(II) complex of 2,2'-bipyridine-5-carboxylic acid methyl ester (L1). The initial reaction appears to have thermodynamic control with the steric bulk of the ligands causing the third ligand to be labile under the reaction conditions used, giving rise to disappointing yields and allowing rearrangement to the more stable facial form. DFT studies indicate that this does not appear to be as a consequence of a metal centered electronic effect. The two isomers of [Ru(L1)3](PF6)2 were separated into the two individual forms using silica preparative plate chromatographic procedures, and the photophysical characteristics of the two forms compared. The results appear to indicate that there is no significant difference in both their room temperature electronic absorption and emission spectra or their excited state lifetimes at 77K.

The isolation and secondary functionalisation of the mer- and fac-isomers of tris(5-hydroxymethyl-2,2 '-bipyridine) complexes of ruthenium(II)

Tris-chelate 5-hydroxymethyl-2,2 '-bipyridine complexes of ruthenium (II) and the structurally related benzo- and naphthoesters have been isolated. The mer-isomer of the alcohol functionalised complex has been isolated by selective precipitation from methylene chloride and was subsequently functionalised to the benzoester with retention of the geometrical isomerism. The fac- and merisomeric forms of the ester complexes were separated using preparative plate silica chromatography and characterised by H-1 NMR spectroscopy. X-ray structural analysis of the fac-isomer of both the ester complexes confirmed the product assignment. The photophysical properties of the three isomers were investigated, indicating very similar absorption spectra to [Ru(biPY)(3)](2+). The emission wavelength was comparable in each case, with the aromatic ester complexes giving a much longer lifetime and higher quantum yields. (c) 2004 Elsevier B.V. All rights reserved.

What do men understand about lifetime risk following genetic testing?:The effect of context and numeracy.

Genetic testing for gene mutations associated with specific cancers provides an opportunity for early detection, surveillance, and intervention (Smith, Cokkinides, & Brawley, 2008). Lifetime risk estimates provided by genetic testing refer to the risk of developing a specific disease within one's lifetime, and evidence suggests that this is important for the medical choices people make, as well as their future family and financial plans. The present studies tested whether adult men understand the lifetime risks of prostate cancer informed by genetic testing. In 2 experiments, adult men were asked to interpret the lifetime risk information provided in statements about risks of prostate cancer. Statement format was manipulated such that the most appropriate interpretation of risk statements referred to an absolute risk of cancer in experiment 1 and a relative risk in experiment 2. Experiment 1 revealed that few men correctly interpreted the lifetime risks of cancer when these refer to an absolute risk of cancer, and numeracy levels positively predicted correct responding. The proportion of correct responses was greatly improved in experiment 2 when the most appropriate interpretation of risk statements referred instead to a relative rather than an absolute risk, and numeracy levels were less involved. Understanding of lifetime risk information is often poor because individuals incorrectly believe that these refer to relative rather than absolute risks of cancer.

Lifetime visual prognosis of patients with glaucoma

BACKGROUND: To investigate the visual outcome of glaucoma patients.

DESIGN: This is a retrospective study of case notes of patients who died while under follow up in a glaucoma clinic of a University Hospital in Scotland between 2006 and 2009.

PARTICIPANTS: Seventy-seven patients were identified.

METHODS: Data collected included type of glaucoma, coexisting pathology and best-corrected visual acuity in Snellen (converted to decimal values) for the first and final clinic visit. The final visual status was evaluated based on the best-corrected visual acuity of the better seeing eye at the last glaucoma clinic visit. Patients who had best-corrected visual acuity of less than Snellen decimal 0.5 were considered not to meet the standards for driving.

MAIN OUTCOME MEASURES: Snellen decimal best-corrected visual acuity, fulfilment of driving standards, and eligibility for partial sight and blind registration at the last clinic visit.

RESULTS: The mean ages at presentation and death were 71.8 ± 10.3 years and 82.2 ± 8.7 years respectively. The mean Snellen decimal best-corrected visual acuity of the better eye at presentation was 0.78, and at the final clinic visit was 0.61. At the final clinic visit, no patients were partial sight registrable, four (5.2%) were blind registrable, and 27 (35.1%) did not fulfil UK driving criteria. Glaucoma patients with other ocular pathologies were more likely to fail UK driving criteria at presentation (P = 0.02) and at last clinic visit (P = 0.03).

CONCLUSION: The majority of glaucoma patients maintained good visual function at the end of their lifetime.

The lifetime direct cost of periodontal treatment:A case study from a norwegian specialist practice

Background: Successful periodontal treatment requires a commitment to regular lifelong maintenance and may be perceived by patients to be costly. This study calculates the total lifetime cost of periodontal treatment in the setting of a specialist periodontal practice and investigates the cost implications of choosing not to proceed with such treatment. Methods: Data from patients treated in a specialist practice in Norway were used to calculate the total lifetime cost of periodontal treatment that included baseline periodontal treatment, regular maintenance, retreatment, and replacing teeth lost during maintenance. Incremental costs for alternative strategies based on opting to forego periodontal treatment or maintenance and to replace any teeth lost with either bridgework or implants were calculated. Results: Patients who completed baseline periodontal treatment but did not have any additional maintenance or retreatment could replace only three teeth with bridgework or two teeth with implants before the cost of replacing additional teeth would exceed the cost of lifetime periodontal treatment. Patients who did not have any periodontal treatment could replace ≤4 teeth with bridgework or implants before a replacement strategy became more expensive. Conclusions: Within the limits of the assumptions made, periodontal treatment in a Norwegian specialist periodontal practice is cost-effective when compared to an approach that relies on opting to replace teeth lost as a result of progressive periodontitis with fixed restorations. In particular, patients who have initial comprehensive periodontal treatment but do not subsequently comply with maintenance could, on average, replace ≤3 teeth with bridgework or two teeth with implants before this approach would exceed the direct cost of lifetime periodontal treatment in the setting of the specialist practice studied. © 2012 American Academy of Periodontology.

Meeting the needs of visually impaired people living in Lifetime Homes

This article explores perceptions on the suitability and effectiveness of Lifetime Homes Standards (LTHS) for those with visual impairment in Northern Ireland.
LTHS are a series of mandatory United Kingdom (UK) public sector housing design interventions, providing a model for ensuring accessible and adaptable homes throughout an occupant's lifespan. An ageing demographic with increasing incidence of diabetes, has led to rising numbers of elderly visually impaired people wanting to remain in their homes for longer.
Qualitative semi structured interviews were conducted with thirteen key stakeholders and thematically analysed. Although findings show that employing LTHS offers benefits to visually impaired residents, short-comings were also identified. Evidence indicates a need for Policy Makers, Health Care Professionals and Housing Associations to modify practices to better meet the housing needs of visually impaired people. Findings may also be applicable to those with other impairments and disabilities in relation to housing for elderly residents.

Growing Up On an Interface: Findings and Implications for the Social Needs, Mental Health and Lifetime Opportunities of Belfast Youth

In this research we aimed to find out what types of risk (if any) affected young people and children growing up in places of high religious segregation or what we normally call interface communities. This is important as we know that risk and experiences of harm and violence can have negative impacts upon development, emotional well-being and future prospects. It is important to understand what types of risk affect young people and children so as we can respond to these in terms of aiding better personal and community development with regard to health, work, education and wider opportunities.