Improvement in adhesion of sputtered TiB2 coating onto high speed steel by a chromium interlayer.

This work addresses at the development of the use of interlayer of different materials for TiB2 coatings with increased adhesion to the substrate and retained high hardness. Ti and Cr were deposited on stationary high speed steel and silicon wafer substrates by magnetron sputtering as an interlayer material. The resultant coatings were evaluated with respect to fundamental properties such as structure, coating roughness, hardness, modulus and adhesion. It was found that the adhesion of resultant TiB2 coatings was increased tremendously with Cr interlayer, whilst the hardness was slightly increased

Dual analysis of loss to follow-up for perinatally HIV-infected adolescents receiving combination antiretroviral therapy in Asia

Background: Perinatally HIV-infected adolescents (PHIVA) are an expanding population vulnerable to loss to follow-up (LTFU). Understanding the epidemiology and factors for LTFU is complicated by varying LTFU definitions. Setting: Asian regional cohort incorporating 16 pediatric HIV services across 6 countries. Methods: Data from PHIVA (aged 10-19 years) who received combination antiretroviral therapy 2007-2016 were used to analyze LTFU through (1) an International epidemiology Databases to Evaluate AIDS (IeDEA) method that determined LTFU as >90 days late for an estimated next scheduled appointment without returning to care and (2) the absence of patient-level data for >365 days before the last data transfer from clinic sites. Descriptive analyses and competing-risk survival and regression analyses were used to evaluate LTFU epidemiology and associated factors when analyzed using each method. Results: Of 3509 included PHIVA, 275 (7.8%) met IeDEA and 149 (4.3%) met 365-day absence LTFU criteria. Cumulative incidence of LTFU was 19.9% and 11.8% using IeDEA and 365-day absence criteria, respectively. Risk factors for LTFU across both criteria included the following: age at combination antiretroviral therapy initiation = 5 years, rural clinic settings compared with urban clinic settings, and high viral loads compared with undetectable viral loads. Age 10-14 years compared with age 15-19 years was another risk factor identified using 365-day absence criteria but not IeDEA LTFU criteria. Conclusions: Between 12% and 20% of PHIVA were determined LTFU with treatment fatigue and rural treatment settings consistent risk factors. Better tracking of adolescents is required to provide a definitive understanding of LTFU and optimize evidence-based models of care