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Given the increasingly global nature of work, the global workforce needs STEM (science, technology, engineering and math) workers who have both STEM content knowledgeandintercultural competence. This study reports on findings from a 10-week bi-national virtual STEM challenge, the World Smarts STEM Challenge, that brought adolescents in the United States and Ghana together to complete a STEM learning program. There were 114 participants from Ghana (female = 56%) and 95 from the US (female = 48%);M_age= 16.21 years,SD= 1.65. In Ghana 100% of participants identified as ethnically Ghanaian and in the US participants identified as Black/African-American (50%), Latino/a/x or Hispanic (23.9%), Asian/Asian-American (7.6%), White/European-American (7.6%), bi-racial or multi-racial (7.6%), and “other” (3.3%). After the Challenge, participants increased in awareness of global issues, and engagement with others, but also showed a small but significant decrease in respect for people from other cultural backgrounds. Girls demonstrated an increase in global-mindedness in both countries and Ghanaian participants reported an increase in self-efficacy for global issues and demonstrated significant growth in both STEM ability self-concept and STEM activism orientation. Findings suggest the value of virtual STEM Challenges for building both STEM and global competence skills. 

In this work, we present a proof-of-concept hydrogel-based sensor system capable of wireless biochemical sensing through measuring backscattered ultrasound. The system consists of silica-nanoparticle embedded hydrogel deposited on a thin glass substrate, presenting two interfaces for backscattering (tissue/hydrogel and hydrogel/glass), which allows for system output to be invariant under the change in acoustic properties (e.g. attenuation, reflection) of the intervening biological tissue. We characterize the effect of silica nanoparticles (acoustic contrast agents) loading on the hydrogel's swelling ratio and its ultrasonic backscattering properties. We demonstrate a wireless pH measurement using dual modes of interrogations, reflection ratio and time delay. The ultrasonic hydrogel pH sensor is demonstrated with a sensing resolution of 0.2 pH level change with a wireless sensing distance around 10 cm. 

Wireless monitoring of the physio-biochemical information is becoming increasingly important for healthcare. In this work, we present a proof-of-concept hydrogel-based wireless biochemical sensing scheme utilizing ultrasound. The sensing system utilizes silica-nanoparticle embedded hydrogel deposited on a thin glass substrate, which presents two prominent interfaces for ultrasonic backscattering (tissue/glass and hydrogel/glass). To overcome the effect of the varying acoustic properties of the intervening biological tissues between the sensor and the external transducer, we implemented a differential mode of ultrasonic back-scattering. Here, we demonstrate a wireless pH measurement with a resolution of 0.2 pH level change and a wireless sensing range around 10 cm in a water tank.