Highly Transparent and Integrable Surface Texture Change Device for Localized Tactile Feedback.

Human-machine haptic interaction is typically detected by variations in friction, roughness, hardness, and temperature, which combines to create sensation of surface texture change. Most of the current technologies work to simulate changes in tactile perception (via electrostatic, lateral force fields, vibration motors, etc.) without creating actual topographical transformations. This makes it challenging to provide localized feedback. Here, a new concept for on-demand surface texture augmentation that is capable of physically forming local topographic features in any predesigned pattern is demonstrated. The transparent, flexible, integrable device comprises of a hybrid electrode system with conductive hydrogel, silver nanowires, and conductive polymers with acrylic elastomer as the dielectric layer. Desired surface textures can be controlled by a predesigned pattern of electrodes, which operates as independent or interconnected actuators. Surface features with up to a height of 0.155 mm can be achieved with a transformation time of less than a second for a device area of 18 cm2 . High transparency levels of 76% are achieved due to the judicious choice of the electrode and the active elastomer layer. The capability of localized and controlled deformations makes this system highly useful for applications such as display touchscreens, touchpads, braille displays, on-demand buttons, and microfluidic devices.

Endoscopic ultrasound-guided liver biopsy using a single-pass, slow-pull technique with a 19-G Franseen tip fine-needle biopsy needle: A prospective study.

BACKGROUND AND AIMS: Endoscopic ultrasound-guided liver biopsy (EUS-LB) is considered to be safe and effective. Commonly a 19-G fine-needle aspiration or biopsy needle is used. But, the results vary with different techniques that are used. Herein, we report the results of liver biopsy with a single-pass, three actuations (1:3) using the slow-pull technique. METHODS: In this prospective study, 50 consecutive patients with indications for liver biopsy underwent EUS-LB with a 19-gauge fine-needle biopsy (FNB) needle from both right and left lobes. The primary outcome was the adequacy of the specimen for histological diagnosis. Total specimen length (TSL), longest specimen length (LSL), complete portal tracts (CPTs) and comparison of these outcomes between the left lobe and right lobe specimens were secondary outcomes. Adverse events (AEs) were also measured during this study. RESULTS: Adequate tissue for histological diagnosis was obtained in all 50 patients (100%). The median number of CPTs was 32.5 (range, 11-58), while the median of TSL was 58 mm (range, 35-190) and the median LSL was 15 mm (range, 5-40). There was no significant difference in CPTs, TSL and LSL between left and right lobe biopsies. There was no major complication; one of the patients (2%) had bleed from the duodenal puncture site, which was managed endoscopically without the need for blood transfusion. CONCLUSIONS: Endoscopic ultrasound-guided liver biopsy using a 19-gauge Franseen tip needle with a single pass, three actuation (1:3) and slow-pull technique provides adequate tissue yield and has a good safety profile.

Indium Tungsten Oxide Thin Films for Flexible High-Performance Transistors and Neuromorphic Electronics.

Thin-film transistors (TFTs) with high electrical performances (mobility > 10 cm2/V s, Vth < 1 V, SS < 1 V/decade, on/off ratio ≈ 106) obtained from the silicon- and oxide-based single-crystalline semiconductor materials require high processing temperature and hence are not suitable for flexible electronics. Amorphous oxide-based transparent electronic devices are attractive to meet emerging technological demands where crystalline oxide-/silicon-based architectures cannot provide a solution. Here, we tackle this problem by using a novel amorphous oxide semiconducting material-namely, indium tungsten oxide (IWO)-as the active channel in flexible TFTs (FTFTs). Post-annealing temperature as low as 270 °C for amorphous IWO thin films deposited by radio frequency sputtering at room temperature could result in smooth morphology ( Rrms ≈ 0.42 nm), good adhesion, and high carrier density ( n ≈ 7.19 × 1018 cm-3). Excellent TFT characteristics of flexible devices could be achieved with linear field effect mobility µFE ≈ 25.86 cm2/V s, subthreshold swing SS ≈ 0.30 V/decade, threshold voltage Vth ≈ -1.5 V, and on/off ratio Ion/ Ioff ≈ 5.6 × 105 at 3 V and stable operation during bending of the FTFT. Additionally, IWO TFTs were implemented as synapses, the building block for neuromorphic computing. Paired-pulse facilitation up to 138% was observed and showed an exponential decay resembling chemical synapses. Utilizing this characteristic, a high-pass dynamic temporal filter was devised providing increased gain from 1.55 to 21 when frequency was raised from 22 to 62 Hz. The high performance and stability of flexible TFTs obtained with IWO films demonstrate their promise for low-voltage electronic applications.

Healable and flexible transparent heaters.

Challenges associated with the mechanical fracture of electrical conductors have hindered the realization of truly flexible high performance wearable electronics. Here, transparent healable electrodes have been developed and examined to alleviate these problems. The composite electrode features a layer of an interconnecting AgNW network on a polyurethane film modified with Diels-Alder adducts (PU-DA). Surface modification using hydrophilic molecules improved adhesion of the AgNW network and resulted in mechanically robust flexible electrodes with a figure of merit sheet resistance of 13.3 Ω â–¡-1 and 77% transmittance at 550 nm. Transparent and flexible healable heaters (TFHH) with good mechanical and thermal stability were fabricated using these electrodes for potential applications in thermochromics, electrically driven displays and defrosters. The PU-DA TFHHs exhibited high Joule heating temperatures of 102 °C with a low operation voltage (6 V), fast thermal response (150 s) and enhanced robustness to endure large repeated mechanical strain for over 500 bending cycles with a small variance in resistance (<10%). After deliberate damage by a knife cut, the electrodes were healed and recovered to their original conductivity via a simple heat treatment at 120 °C. Uniquely, the healing process can also be triggered by utilising electrical power.

Transparent Flexible Multifunctional Nanostructured Architectures for Non-optical Readout, Proximity, and Pressure Sensing.

Electronic skins need to be versatile and able to detect multiple inputs beyond simple pressure and touch while having attributes of transparency and facile manufacturability. Herein, we demonstrate a versatile nanostructured transparent sensor capable of detecting wide range of pressures and proximity as well as novel nonoptical detection of printed patterns. The architecture and fabrication processes are straightforward and show robustness to repeated cycling and testing. The sensor displays good sensitivity and stability from 30 Pa to 5 kPa without the use of microstructuration and is conformal and sensitive to be utilized as a wrist-based heart-rate monitor. Highly sensitive proximity detection is shown from a distance of 9 cm. Finally, a unique nonoptical pattern recognition dependent on the difference in the dielectric constant between ink and paper is also demonstrated, indicating the multifunctionality of this simple architecture.