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: Introduction: Guidelines regarding antiretroviral therapy (ART) initiation in HIV infection have varied over time, with the 2015 World Health Organization recommendation suggesting ART initiation at the time of diagnosis regardless of CD4 T‐cell counts. Herein, we investigated the influence of socio‐demographic and clinical factors in addition to time trends on early ART initiation among participants of the Montreal Primary HIV Infection Study. Methods: The Montreal Primary HIV Infection Study is a prospective cohort established in three community medical centres (CMCs) and two university medical centres (UMCs). Recently diagnosed HIV‐infected adults were categorized as receiving early (vs. delayed) ART if ART was initiated within 180 days of the baseline visit. Associations between early ART initiation and socio‐demographic, socio‐economic and behavioural information were examined. Independent associations of factors linked with early ART initiation were determined using multivariable binary logistic regression analysis. Results: A total of 348 participants had a documented date of HIV acquisition of Conclusions: Early ART initiation during primary HIV infection was associated with diminished biological prognostic factors and calendar time mirroring evolution of treatment guidelines. In addition, socio‐economic factors such as having a paid employment, contribute to early ART initiation in the context of universal access to care in Canada., Introduction Human immunodeficiency virus (HIV) affects over 36.7 million people worldwide. Nearly, half of those infected with HIV remain untreated, increasing their risks for acquired immune deficiency syndrome (AIDS), onward [...]

The treatment of oxygen-containing hydrogen plasma on electrochemically etched porous silicon leads to buried psi layer which is partially oxidized. These layers exhibit bright photoluminescence and are covered with a thin nonluminescing SiO2 layer. Different analyses reveal the non-uniform incorporation of oxygen in the porous silicon layer. An O/Si ratio is related to the increase in photoluminescence.

We establish, using a tetrahedral model, the bonding properties of amorphous silicon oxynitride (a-SiOxNy) films deposited at low temperatures (LTs) by electron-cyclotron resonance chemical-vapor deposition (ECRCVD) on several substrates and under various conditions of gas flows and total gas pressure in a dilute mixture of SiH4+N2 in Ar. The atomic percentage of each tetrahedral unit incorporated in the film network is calculated from the deconvolution of the high-resolution x-ray photoelectron spectroscopy (XPS) spectra in the Si 2p3/2 region and corroborated by the results obtained from both survey scans and the high-resolution XPS spectra in the N 1s region. The Si3N4 phase is the most important one and the only bonding unit which is incorporated in all our LT ECRCVD SiOxNy films. The incorporation of all the other component tetrahedrons depends strongly on growth conditions. The threshold values of the N/Si atomic ratio for which intrinsic defects, such as Si–Si bonds, are not incorporated in the network depend on the O/Si ratio incorporated in the films, mainly due to the competition between oxygen and nitrogen atoms in their reaction with silicon dangling bonds. The effect of the total gas pressure on the atomic percentages of the oxidation states present in the LT ECRCVD SiOxNy films is qualitatively similar to the effect of the ion bombarding energy or the plasma density. O–N bonds are present only in samples having high amount of oxygen and nitrogen in their networks. For these films, our results show unambiguously the presence of the N–Si2O tetrahedron and suggest that N–Si3-νOν tetrahedrons with ν>=2 are not incorporated in their networks. A correlation is observed between the N–Si2O and the Si–O3(ON) tetrahedrons whose component peak is localized at (104.0±0.2) eV in the Si 2p3/2 region of the XPS data, which suggests that both bonding units coexist in these films as some sort of complex bonding configuration. [ABSTRACT FROM AUTHOR]

A tetrahedral model is presented to explain the bonding properties of nonstoichiometric amorphous silicon oxynitride (a-SiOxNy) alloys, grown under highly nonequilibrium conditions, whose structures obey neither the random bonding model nor the random mixture model. Based on our approach, a numerical procedure is proposed to obtain the relative atomic percentages of each component structural phase from the deconvolution of the high-resolution x-ray photoelectron spectroscopy (XPS) spectra in the Si 2p3/2 region. The tetrahedral model is then used to study the bonding properties of a-SiOxNy films grown by electron-cyclotron resonance plasma-enhanced chemical-vapor deposition, having relatively low values of the O/Si atomic ratio (<=0.37) incorporated in their networks. The experimental results show that five tetrahedral phases (tetrahedrons Si–Si4, Si–Si2ON, Si–N4, Si–Si3O, and Si–O4) are present in a-SiOxNy films with low N/Si atomic ratios (<=0.93), while only three phases (Si–SiON2, Si–N4, and Si–O2N2) are present in samples with higher N/Si atomic ratios (>=1.12). The Si3N4 phase is the most important bonding unit and it is the only phase present in all our samples. These results are corroborated by survey scans and by comparison with the high-resolution XPS spectra in the N 1s region. They support the validity of the model proposed for a-SiOxNy alloys and the XPS analysis, correlated with growth conditions, presented in this work. [ABSTRACT FROM AUTHOR]

We establish the role of oxygen atoms on the structural, chemical, and mechanical properties of SiO[sub X]N[sub Y] films grown on Si and InP substrates by electron-cyclotron resonance chemical-vapor deposition (ECR CVD) using a diluted SiH[sub 4] and N[sub 2] mixture in Ar, under controlled conditions. The mechanical and chemical properties of ECR-CVD SiN[sub X] films depend on the oxygen contamination even when this element is present in low concentrations. The compressive stress of SiN[sub X] films deposited with a low (and constant) content of oxygen (less than 12%) is shown to be in qualitative agreement with a model of repulsive Coulomb forces related mainly to polar [sup -]N-H[sup +] units in the SiN[sub X] network. We observe a decrease of the film compressive stress when the N[sub 2]/SiH[sub 4] flow ratio increases, which is due to the increase of Si-N bonds in detriment of N-H bonds. Films deposited with high oxygen content in the plasma show a decrease of nitrogen incorporation. Oxygen radicals species compete with those of nitrogen in their reaction with silicon dangling bonds, which has as a consequence a decrease in the incorporation of nitrogen. Additional creation of oxygen radicals, with no hydrogen dilution, is more effective in decreasing the number of N-H bonds, or the compressive stress in the SiN[sub X] films, than the corresponding creation of nitrogen radicals. The mechanical properties of SiN[sub X] films contaminated with oxygen are controlled, in general, by the total number of both nitrogen plus oxygen atoms relative to silicon. The buffered HF (BHF) film etch rate is enhanced and thus is mainly controlled by the oxygen content. Low values of the compressive stress do not necessarily imply low values of BHF etch rate or a high N/Si ratio. We also present a discussion of the origin of the unintentional incorporation of oxygen in a ECR-CVD system designed for industrial production. [ABSTRACT FROM AUTHOR]

The bonding properties of amorphous silicon oxynitride (SiO(sub x)N(sub y)) films deposited at low temperatures (LTs) by electron-cyclotron resonance chemical-vapor deposition (ECRCVD) on several substrates and under various conditions of gas flows and total gas pressure in a dilute mixture of SiH(sub 4)+N(sub 2) in Ar was established using tetrahedral model. The Si(sub 3)N(sub 4) phase is the most important one and the only bonding unit that is incorporated in all LT ECRCVD SiO(sub x)N(sub y) films.

An extension of the random mixture model (ERMM) is developed to study the bonding properties of amorphous-SiOxNy films. Based on this ERMM, the relative atomic percentage of each tetrahedral phase incorporated in the film network is obtained from the deconvolution of the high-resolution x-ray photoelectron spectroscopy spectra in the Si 2p(sub 3/2) region.