Ideal Spin Filters: Theoretical Study of Electron Transmission Through Ordered and Disordered Interfaces Between Ferromagnetic Metals and Semiconductors

It is predicted that certain atomically ordered interfaces between some ferromagnetic metals (F) and semiconductors (S) should act as ideal spin filters that transmit electrons only from the majority spin bands or only from the minority spin bands of the F to the S at the Fermi energy, even for F with both majority and minority bands at the Fermi level. Criteria for determining which combinations of F, S and interface should be ideal spin filters are formulated. The criteria depend only on the bulk band structures of the S and F and on the translational symmetries of the S, F and interface. Several examples of systems that meet these criteria to a high degree of precision are identified. Disordered interfaces between F and S are also studied and it is found that intermixing between the S and F can result in interfaces with spin anti-filtering properties, the transmitted electrons being much less spin polarized than those in the ferromagnetic metal at the Fermi energy. A patent application based on this work has been commenced by Simon Fraser University.Comment: RevTeX, 12 pages, 5 figure

Implementation of Safety Management System for Improving Construction Safety Performance: A Structural Equation Modelling Approach

The construction industry contributes to a large proportion of industrial injury and mortality. It is of high importance to evaluate the effectiveness of the Safety Management System (SMS). In particular, it is necessary to compare the quality and level of achievement of SMS and safety performance of a construction project. However, a sizeable sample of construction accidents is often not available. Therefore, possible proxies to indicate the safety performance were established. Moreover, the motivation factors which characterize the quality and level of achievement should be identified. In this study, a structural model has been established to examine the relationship between the SMS implementation and operational & safety performance of the construction projects. Results of the structural model illustrated the relationship between (i) SMS implementation and project safety outcome, (ii) SMS implementation and five motivation factors, and (iii) project safety outcome and six proxies. Results of this study have unfolded the motivation factors in SMS implementation and their subsequent effects on project performance, throwing light on the need to enhance the safety management practice in order to reduce accidents and injuries in the construction industry in the long run

Household characteristics and influenza vaccination uptake in the community-dwelling elderly: a cross-sectional study

Elderly people are at higher risk of influenza diseases. The morbidity benefit of vaccination is often offset by its low and variable coverage in elderly people in the community. To assess household and individual factors associated with influenza vaccination uptake in the community-dwelling elderly of age ≥65, data from a cross-sectional Thematic Household Survey conducted in 2011/12 in Hong Kong were analysed, using vaccination in the past 12 months as the outcome variable. Households comprising an elderly person living with non-elderly member(s) of age ≤64 were also evaluated. Data fields included socio-demographics, household structures, health status, eligibility to financial subsidy, and subscription to health insurance. The influenza vaccination rate was 27% in 4204 elderly persons from 3224 households. Being male, being economically active, attaining primary education, having smoking behaviours were negatively associated with vaccination, while chronic illness and age ≥70 were positively associated factors. Elderly people living alone gave a variable rate of vaccination ranging from 16.4% in males of age 65–69 to 36.3% in females ≥70. Household size per se was not associated with vaccination, but a positive correlation could be seen if the household was composed of vaccinated non-elderly member(s). Influenza vaccination uptake in the community-dwelling elderly is dependent on both individual and household characteristics, the latter including the influence of vaccinated non-elderly member(s). The low vaccination coverage of “younger” (age 65–69) elderly men living alone is particularly worrisome. Interventions focusing on vulnerable elderly people and their social networks would be desirable

Paper Spray Ionisation Ion Mobility Mass Spectrometry of Sebum Classifies Biomarker Classes for the Diagnosis of Parkinson’s Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder and identification of robust biomarkers to complement clinical diagnosis will accelerate treatment options. Here we demonstrate the use of direct infusion of sebum from skin swabs using paper spray ionisation coupled with ion mobility mass spectrometry (PS-IM-MS) to determine the regulation of molecular classes of lipids in sebum that are diagnostic of PD. A PS-IM-MS method for sebum samples that takes three minutes per swab was developed and optimised. The method was applied to skin swabs collected from 150 people and elucidates ~ 4200 features from each subject which were independently analysed. The data included high molecular weight lipids (>600 Da.) that differ significantly in the sebum of people with PD. Putative metabolite annotations of several lipid classes, predominantly triglycerides and larger acyl glycerides, were obtained using accurate mass, tandem mass spectrometry and collision cross section measurements

Paper Spray Ionization Ion Mobility Mass Spectrometry of Sebum Classifies Biomarker Classes for the Diagnosis of Parkinson's Disease

[Image: see text] Parkinson’s disease (PD) is the second most common neurodegenerative disorder, and identification of robust biomarkers to complement clinical diagnosis will accelerate treatment options. Here, we demonstrate the use of direct infusion of sebum from skin swabs using paper spray ionization coupled with ion mobility mass spectrometry (PS-IM-MS) to determine the regulation of molecular classes of lipids in sebum that are diagnostic of PD. A PS-IM-MS method for sebum samples that takes 3 min per swab was developed and optimized. The method was applied to skin swabs collected from 150 people and elucidates ∼4200 features from each subject, which were independently analyzed. The data included high molecular weight lipids (>600 Da) that differ significantly in the sebum of people with PD. Putative metabolite annotations of several lipid classes, predominantly triglycerides and larger acyl glycerides, were obtained using accurate mass, tandem mass spectrometry, and collision cross section measurements