Photo-oxidative Crack Propagation in Transition Metal Dichalcogenides.

Monolayered transition-metal dichalcogenides (TMDs) are easily exposed to air, and their crystal quality can often be degraded via oxidation, leading to poor electronic and optical device performance. The degradation becomes more severe in the presence of defects, grain boundaries, and residues. Here, we report crack propagation in pristine TMD monolayers grown by chemical vapor deposition under ambient conditions and light illumination. Under a high relative humidity (RH) of ∼60% and white light illumination, the cracks appear randomly. Photo-oxidative cracks gradually propagated along the grain boundaries of the TMD monolayers. In contrast, under low RH conditions of ∼2%, cracks were scarcely observed. Crack propagation is predominantly attributed to the accumulation of water underneath the TMD monolayers, which is preferentially absorbed by hygroscopic alkali metal-based precursor residues. Crack propagation is further accelerated by the cyclic process of photo-oxidation in a basic medium, leading to localized tensile strain. We also found that such crack propagation is prevented after the removal of alkali metals via the transfer of the sample to other substrates.

Everyday disease diplomacy: an ethnographic study of diabetes self-care in Vietnam.

BACKGROUND: Understanding people's subjective experiences of everyday lives with chronic health conditions such as diabetes is important for appropriate healthcare provisioning and successful self-care. This study explored how individuals with type 2 diabetes in northern Vietnam handle the everyday life work that their disease entails. METHODS: Detailed ethnographic data from 27 extended case studies conducted in northern Vietnam's Thái Bình province in 2018-2020 were analyzed. RESULTS: The research showed that living with type 2 diabetes in this rural area of Vietnam involves comprehensive everyday life work. This work often includes efforts to downplay the significance of the disease in the attempt to stay mentally balanced and ensure social integration in family and community. Individuals with diabetes balance between disease attentiveness, keeping the disease in focus, and disease discretion, keeping the disease out of focus, mentally and socially. To capture this socio-emotional balancing act, we propose the term "everyday disease diplomacy." We show how people's efforts to exercise careful everyday disease diplomacy poses challenges to disease management. CONCLUSIONS: In northern Vietnam, type 2 diabetes demands daily labour, as people strive to enact appropriate self-care while also seeking to maintain stable social connections to family and community. Health care interventions aiming to enhance diabetes care should therefore combine efforts to improve people's technical diabetes self-care skills with attention to the lived significance of stable family and community belonging.