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Recently, antiferroelectric and antiferroelectric‐like materials have regained interest in electronic devices, such as field‐effect transistors, memory, and transducers. Particularly in micro/nano‐electromechanical coupling systems such as actuators, these innovative materials, with their peculiar phase transition between antiferroelectric and ferroelectric phases, show promise in offering large electro‐strain, fast response, and low power consumption devices. However, compared to numerous computational models of ferroelectric actuators, numerical modeling of antiferroelectric and antiferroelectric‐like actuators remains relatively unexplored. In this paper, we propose a phenomenological model of uniaxial antiferroelectric and antiferroelectric‐like actuators based on their switching polarization behavior. Specifically, both the double hysteresis loop of antiferroelectric materials and the pinched hysteresis loop of antiferroelectric‐like materials can be captured by two hyperbolic tangent functions. This allows us to cast a polarization‐dependent strain and piezoelectric tensor into the constitutive laws. The proposed model is then implemented into a finite element framework, in which the voltage‐induced deformation can be solved using the Newton–Raphson procedure. Numerical examples of both antiferroelectric and antiferroelectric‐like actuators are illustrated and compared with experimental data, showing our proposed model can serve as a useful tool for the design and development of antiferroelectric and antiferroelectric‐like actuators. [ABSTRACT FROM AUTHOR]

Background: Myanmar National AIDS programme's priority is to improve the survival of all people living with HIV by providing anti-retroviral therapy (ART) care. More than 7200 children (aged <15 years) have been enrolled into ART care from 2005 to 2016. A previous study showed that ~11% children on ART care had either died or were lost to follow-up by 60 months. Factors associated with death and lost-to follow-up (adverse outcomes) have not been previously studied., Objectives: To describe the association between demographic and clinical characteristics at enrollment into ART care with adverse outcomes., Methods: Cohort study using records of children enrolled for ART care at Mingalardon Specialist Hospital (main Paediatric ART center in Myanmar) from 2006-2016. We used multivariable Cox proportional hazards regression models for analysis., Results: 1,159 children were enrolled for ART care and they contributed a total of 1.45 million person-days of follow-up period. 112 (10%) had an adverse outcome during the follow-up time period (55 deaths, 57 lost to follow-up). Enrollment into the ART care through in-patient care department of the hospital, CD4 Cell count <50/mm3, enrollment during changing ART guidelines (different ART eligibility criteria and preferred ART regimen) were independently associated with higher hazards of adverse outcome. Receiving protease inhibitor-based ART regimen at enrollment was independently associated with lower hazards of adverse outcome. Age, sex, residing in urban or rural areas, WHO clinical stage, having TB at the time of enrollment, receiving cotrimoxazole prophylaxis were not statistically associated with adverse outcomes., Conclusion: Our analysis reconfirms good survival of children on ART care (including those with TB). The characteristics associated with adverse outcomes (other than CD4 cell count<50) are surrogates of some unmeasured underlying health system/ patient related factors that needs further exploration to improve the survival of children on ART care.