SARS-CoV-2 presence in wastewater has been reported in several studies and has received widespread attention among the Wastewater-based epidemiology (WBE) community. Such studies can potentially be used as a proxy for early warning of potential COVID-19 outbreak, or as a mitigation measure for potential virus transmission via contaminated water. In this review, we summarized the latest understanding on the detection, concentration, and evaluation of SARS-CoV-2 in wastewater. Importantly, we discuss factors affecting the quality of wastewater surveillance ranging from temperature, pH, starting concentration, as well as the presence of chemical pollutants. These factors greatly affect the reliability and comparability of studies reported by various communities across the world. Overall, this review provides a broadly encompassing guidance for epidemiological study using wastewater surveillance.

Additive manufacturing (AM) has progressed rapidly in recent years, thanks to its versatility in printing complex and intricate shapes. Very recently, it has also been making inroads into functional and energy materials. On the other hand, thermoelectrics is a relatively mature field, with well-established understanding and design, especially on the materials level. However, complexities in device fabrication and scalability issues have greatly hindered thermoelectric (TE) applications. In this Focus Review, we discuss the advent of AM as a timely and important tool not only to overcome the scalability issues but also to achieve shape intricacies and conformability for flexible and wearable applications. In particular, direct ink writing (DIW), a subset under materials extrusion methods, holds great promise as a versatile fabrication technique for integrated TE devices. More importantly, we discuss the great promise of “engineered nanostructuring” using DIW as a new paradigm to improve TE performance beyond intrinsic properties.

GeTe is among the best medium-temperature thermoelectrics. Its high performance originates from band convergence at phase transition and low lattice thermal conductivity due to Peierls distortion. In most works, the...