Atomic layer deposition of LiF using LiN(SiMe3)2 and SF6 plasma

Lithium fluoride films were prepared by atomic layer deposition (ALD) using a new route in which LiN(SiMe₃)₂ is used as a precursor and SF₆ plasma as a coreactant. Conformal LiF films were deposited at 150 °C at a growth rate of ∼0.4 Å per cycle. All deposited films were polycrystalline and slightly lithium-rich with a composition of LiF_0.8, independently of the plasma conditions (e.g. exposure time, pressure and power). The levels of H, C, N, O, Si, and S were all <1 at%. Spectroscopic ellipsometry measurements were carried out over the wavelength range of 140-2480 nm and showed a refractive index of 1.37 at 633 nm for films deposited using 1 s plasma exposure time. We conclude that short plasma exposures are preferred, since a prolonged exposure time leads to an increase in optical absorption and lower growth per cycle values. Furthermore, mass spectrometry measurements revealed the formation of SiMe₃F species during both half-cycles, originating from the reaction between the precursor ligands and fluorine species present either at the surface or in the plasma. Moreover, the SF₆ plasma step led to the formation of fluorocarbon species, suggesting that dissociation and recombination in the plasma takes place. Overall, this work demonstrates that SF₆ plasma offers a promising alternative to other coreactants for ALD of high purity lithium fluoride.

Plasma-assisted and thermal atomic layer deposition of electrochemically active Li2CO3

Growth per cycle as a function of process table temperature for both plasma-assisted (squares) and thermal (circles) ALD processes.

Zika virus in the Americas: Early epidemiological and genetic findings

Brazil has experienced an unprecedented epidemic of Zika virus (ZIKV), with ~30,000 cases reported to date. ZIKV was first detected in Brazil in May 2015, and cases of microcephaly potentially associated with ZIKV infection were identified in November 2015. We performed next-generation sequencing to generate seven Brazilian ZIKV genomes sampled from four self-limited cases, one blood donor, one fatal adult case, and one newborn with microcephaly and congenital malformations. Results of phylogenetic and molecular clock analyses show a single introduction of ZIKV into the Americas, which we estimated to have occurred between May and December 2013, more than 12 months before the detection of ZIKV in Brazil. The estimated date of origin coincides with an increase in air passengers to Brazil from ZIKV-endemic areas, as well as with reported outbreaks in the Pacific Islands. ZIKV genomes from Brazil are phylogenetically interspersed with those from other South American and Caribbean countries. Mapping mutations onto existing structural models revealed the context of viral amino acid changes present in the outbreak lineage; however, no shared amino acid changes were found among the three currently available virus genomes from microcephaly cases. Municipality-level incidence data indicate that reports of suspected microcephaly in Brazil best correlate with ZIKV incidence around week 17 of pregnancy, although this correlation does not demonstrate causation. Our genetic description and analysis of ZIKV isolates in Brazil provide a baseline for future studies of the evolution and molecular epidemiology of this emerging virus in the Americas.

Self-management, health service use and information seeking for diabetes care among recent immigrants in Toronto

INTRODUCTION

Our objective was to explore self-management practices, health services use and information-seeking for type 2 diabetes care among adult men and women from four recent immigrant communities in Toronto.

METHODS

A structured questionnaire was adapted for the Canadian context and translated into 4 languages. A total of 184 participants with type 2 diabetes-130 recent immigrants and 54 Canadian-born-were recruited in both community and hospital settings.

RESULTS

Recent immigrants were significantly less likely than the Canadian-born group to perform regular blood glucose and foot checks and significantly more likely than the Canadian-born group to be non-smokers, participate in regular physical activity and reduce dietary fat. Recent immigrants were significantly less likely than the Canadian-born group to use a specialist, alternative provider and dietician and less likely to report using dieticians, nurses and diabetes organizations as sources of diabetes-related information. Important differences were observed by sex and country of origin.

CONCLUSION

Findings suggest that diabetes prevention and management strategies for recent immigrants must address linguistic, financial, informational and systemic barriers to information and care.

Selective Grafting of Amine Groups on Polyethylene by Means of Modulated RF NH3 Plasmas

Plasma treatments in power modulated NH3 RF glow discharges have been performed for modifying the surface of polyethylene (PE). Time Resolved Optical Emission Spectroscopy (TR-OES) has been utilized for monitoring the emission of active species during the modulation period of the discharge, Electron Spectroscopy for Chemical Analysis (ESCA) has been used for studying the surface composition of PE before and after the derivatization of plasmagrafted -NH2 groups. We present our preliminary results here, which show how modulated NH3 plasmas can effectively improve the grafting selectivity of -NH2 respect to all other N-containing groups.

Plasma Treatment of Polymers for Improving Al Adhesion

PET and Kapton thin films have been plasma processed in order to increase sputtered aluminum adhesion. The effect of different plasma feedings, such as NH3, O2, and He, has been evaluated on polymer/metal adhesion and on chemical modifications of polymer surface at different plasma power and treatment time. The chemistry at polymer/metal interface has been studied in order to find the suitable experimental conditions for transferring the plasma process to industrial scale.

The role of acid-base reactions in promoting Polymer/Aluminum adhesion has been investigated. Surface composition has been investigated by X-ray Photoelectron Spectroscopy; adhesion measurements have been accomplished by 180° Peel Test.

A capacitive probe with shaped probe bias for ion flux measurements in depositing plasmas

The application of a pulse shaped biasing method implemented to a capacitive probe is described. This approach delivers an accurate and simple way to determine ion fluxes in diverse plasma mixtures. To prove the reliability of the method, the ion probe was used in a different configuration, namely, a planar Langmuir probe. In this configuration, the ion current was directly determined from the I-V characteristic and compared with the ion current measured with the pulse shaped ion probe. The results from both measurements are in excellent agreement. It is demonstrated that the capacitive probe is able to perform spatially resolved ion flux measurements under high deposition rate conditions (2-20 nm/s) in a remote expanding thermal plasma in Ar/NH(3)/SiH(4) mixture.

Monitoring mental health reform in a Canadian inner city

This ecological study investigated whether the relationship between social disadvantage and hospitalization for psychoses changed during a time of social and economic stressors in an urban setting. Hospital separation rates were compared in the census years 1991 and 1996. Rates were 66% higher in the lowest income areas compared to the richest areas; but this relationship did not change over time. Instead, rates for psychoses increased by about 15% over time. These findings may be due to an increase in the need, a change in the level of resources or in coding practices. As hospital separation data are collected systematically in many countries, they can be used to monitor the progress of mental health reform. Variations in an area may signify that resources need to be redistributed more equitably and/or at a faster pace.