Wearable pressure sensors have been attracting great attention for a variety of practical applications, including electronic skin, smart textiles, and healthcare devices. However, it is still challenging to realize wearable pressure sensors with sufficient sensitivity and low hysteresis under small mechanical stimuli. Herein, we introduce simple, cost-effective, and sensitive capacitive pressure sensor based on porous Ecoflex-multiwalled carbon nanotube composite (PEMC) structures, which leads to enhancing the sensitivity (6.42 and 1.72 kPa–1 in a range of 0–2 and 2–10 kPa, respectively) due to a synergetic effect of the porous elastomer and percolation of carbon nanotube fillers. The PEMC structure shows excellent mechanical deformability and compliance for an effective integration with practical wearable devices. Also, the PEMC-based pressure sensor shows not only the long-term stability, low-hysteresis, and fast response under dynamic loading but also the high robustness against temperature and humidity changes. Finally, we demonstrate a prosthetic robot finger integrated with a PEMC-based pressure sensor and an actuator as well as a healthcare wristband capable of continuously monitoring blood pressure and heart rate.
RNA polymerase III (Pol III) transcribes medium-sized non-coding RNAs (collectively termed Pol III genes). Emerging diverse roles of Pol III genes suggest that individual Pol III genes are exquisitely regulated by transcription and epigenetic factors. Here we report global Pol III expression/methylation profiles and molecular mechanisms of Pol III regulation that have not been as extensively studied, using nc886 as a representative Pol III gene. In a human mammary epithelial cell system that recapitulates early breast tumorigenesis, the fraction of actively transcribed Pol III genes increases reaching a plateau during immortalization. Hyper-methylation of Pol III genes inhibits Pol III binding to DNA via inducing repressed chromatin and is a determinant for the Pol III repertoire. When Pol III genes are hypo-methylated, MYC amplifies their transcription, regardless of its recognition DNA motif. Thus, Pol III expression during tumorigenesis is delineated by methylation and magnified by MYC.
A number of flexible and stretchable strain sensors based on piezoresistive and capacitive principles have been recently developed. However, piezoresistive sensors suffer from poor long-term stability and considerable hysteresis of signals. On the other hand, capacitive sensors exhibit limited sensitivity and strong electromagnetic interference from the neighboring environment. In order to resolve these problems, a novel stretchable strain sensor based on the modulation of optical transmittance of carbon nanotube (CNT)-embedded Ecoflex is introduced in this paper. Within the film of multiwalled CNTs embedded in the Ecoflex substrate, the microcracks are propagated under tensile strain, changing the optical transmittance of the film. The proposed sensor exhibits good stretchability (ε ≈ 400%), high linearity (R 2 > 0.98) in the strain range of ε = 0−100%, excellent stability, high sensitivity (gauge factor ≈ 30), and small hysteresis (∼1.8%). The sensor was utilized to detect the bending of the finger and wrist for the control of a robot arm. Furthermore, the applications of this sensor to the real-time posture monitoring of the neck and to the detection of subtle human motions were demonstrated.
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