Highly Stretchable, Knittable, Wearable Fiberform Hydrovoltaic Generators Driven by Water Transpiration for Portable Self-Power Supply and Self-Powered Strain Sensor.

The development of excellently stretchable, highly mobile, and sustainable power supplies is of great importance for self-power wearable electronics. Transpiration-driven hydrovoltaic power generator (HPG) has been demonstrated to be a promising energy harvesting strategy with the advantages of negative heat and zero-carbon emissions. Herein, this work demonstrates a fiber-based stretchable HPG with the advantages of high output, portability, knittability, and sustainable power generation. Based on the functionalized micro-nano water diffusion channels constructed by the discarded mask straps (MSs) and oxidation-treated carbon nanomaterials, the applied water can continuously produce electricity during the spontaneous flow and diffusion. Experimentally, when a tiny 0.1 mL of water encounters one end of the proposed HPG, the centimeter-length device can yield a peak voltage of 0.43 V, peak current of 29.5 µA, and energy density of 5.833 mW h cm-3. By efficiently integrating multiple power generation units, sufficient output power can be provided to drive commercial electronic devices even in the stretched state. Furthermore, due to the reversibility of the electrical output during dynamic stretching-releasing, it can passively convert physiological activities and motion behaviors into quantifiable and processable current signals, opening up HPG's application in the field of self-powered wearable sensing.

Modelling effectiveness of COVID-19 pandemic control policies using an Area-based SEIR model with consideration of infection during interzonal travel.

This paper studies the effectiveness of several pandemic restriction measures adopted in Singapore during the COVID-19 outbreak. To this end, the classical Susceptible-Exposed-Infectious-Recovered (SEIR) model widely used to describe the dynamic process of epidemic propagation is extended to an area-based SEIR model with the consideration of exposure to infections during commute and quarantine. The proposed model considers infections within areas and infections occurred during the commute of individuals. A case study of the Singapore MRT system is presented to show the effectiveness of pandemic restriction policies implemented in Singapore, namely social distancing, work shift and Circuit Breaker (CB) and phase advisories. A long-term investigation of COVID-19 pandemic in Singapore is performed, and the disease transmission dynamics in 2020-2021 (which covers the first wave and second wave of COVID-19 pandemic in Singapore) is modelled.

A highly electrocatalytic, stretchable, and breathable enzyme-free electrochemical patch based on electrospun fibers decorated with platinum nano pine needles for continuous glucose sensing in neutral conditions.

Given the worldwide increase in diabetes, there is an urgent need for glucose sensors that can achieve the on-body detection of glucose concentration. With the development of nanomaterials and flexible electronics, wearable electrochemical enzyme-free glucose biosensors that can conveniently, continuously and stably monitor the glucose concentrations of diabetes patients without invasion and risk of infection are coming into focus. However, despite the enormous efforts toward wearable electrochemical enzyme-free glucose sensors, there have been limited achievements in developing a stretchable and breathable glucose sensor with high sensitivity, low detection limit, and excellent catalytic activity towards glucose oxidation in neutral media, to meet the need for continuous wearable glucose monitoring in scenarios such as the on-body detection of glucose in human sweat. Herein, we demonstrate a novel electrochemical enzyme-free glucose-sensing patch on the foundation of electrospun polyurethane (PU) fibrous mats to address some of the aforementioned challenges. The sensing patch was fabricated through a facile technology of electrospinning, followed by magnetron sputtering of gold (Au) to enable high conductivity. After that, ultrasonic-assisted electrodeposition was utilized to in situ introduce well-dispersed platinum nano pine needles along each fiber. Due to the good stretchability of PU materials, porous structure, and large specific surface area of electrochemical sites, the glucose-sensing patch promises merits such as good stretchability (performs well under 10% strain), high sensitivity (203.13 µA mM-1 cm-1), prominently low detection limit (14.77 µM), excellent selectivity, and efficient vapor permeability. Notably, the advanced hierarchical nanostructures with excellent catalytic activity towards glucose oxidation could be capable of detecting glucose in neutral conditions (pH = 7.4) without the assistance of enzymes. Given the facile fabrication methods and the integrated superior performances, this enzyme-free glucose-sensing patch could play a vital role in wearable glucose sensors.