Strain-Sensor-In-Pixel Technology for Resolution-Sustainable Stretchable Displays.

One of the limitations of stretchable displays is the severe degradation of resolution or the decrease in the number of pixels per unit area when stretched. Hence, we suggest a strain-sensor-in-pixel (S-SIP) system through the adoption of hidden pixels that are activated only during the stretch mode for maintaining the density of on-state pixels. For the S-SIP system, the gate and source electrodes of InGaZnO thin-film transistors (TFTs) in an existing pixel are connected to a resistive strain sensor through the facile and selective deposition of silver nanowires (AgNWs) via electrohydrodynamic-jet-printing. With this approach, the strain sensor integrated TFT functions as a strain-triggered switch, which responds only to stretching along the designated axes by finely tuning the orientation and cycles of AgNW printing. The strain sensor-integrated TFT remains in an off-state when unstretched and switches to an on-state when stretched, exhibiting a large negative gauge factor of -1.1 × 1010 and a superior mechanical stability enduring 6000 cycles, which enables the efficient structure to operate hidden pixels without requiring additional signal processing. Furthermore, the stable operation of the S-SIP in a 5 × 5-pixel array is demonstrated via circuit simulation, implying the outstanding applicability and process compatibility to the conventional active-matrix display backplanes.

Monolayer, open-mesh, pristine PEDOT:PSS-based conformal brain implants for fully MRI-compatible neural interfaces.

Understanding brain function is essential for advancing our comprehension of human cognition, behavior, and neurological disorders. Magnetic resonance imaging (MRI) stands out as a powerful tool for exploring brain function, providing detailed insights into its structure and physiology. Combining MRI technology with electrophysiological recording system can enhance the comprehension of brain functionality through synergistic effects. However, the integration of neural implants with MRI technology presents challenges because of its strong electromagnetic (EM) energy during MRI scans. Therefore, MRI-compatible neural implants should facilitate detailed investigation of neural activities and brain functions in real-time in high resolution, without compromising patient safety and imaging quality. Here, we introduce the fully MRI-compatible monolayer open-mesh pristine PEDOT:PSS neural interface. This approach addresses the challenges encountered while using traditional metal-based electrodes in the MRI environment such as induced heat or imaging artifacts. PEDOT:PSS has a diamagnetic property with low electrical conductivity and negative magnetic susceptibility similar to human tissues. Furthermore, by adopting the optimized open-mesh structure, the induced currents generated by EM energy are significantly diminished, leading to optimized MRI compatibility. Through simulations and experiments, our PEDOT:PSS-based open-mesh electrodes showed improved performance in reducing heat generation and eliminating imaging artifacts in an MRI environment. The electrophysiological recording capability was also validated by measuring the local field potential (LFP) from the somatosensory cortex with an in vivo experiment. The development of neural implants with maximized MRI compatibility indicates the possibility of potential tools for future neural diagnostics.

Floristic inventory and distribution characteristics of algific talus slopes in a specific area of forest biodiversity in South Korea.

Background: This study conducted a survey for establishing in-situ and ex-situ conservation measures for northern lineage plants that are vulnerable to climate change and for designating Forest Genetic Resource Reserve for 25 algific talus slope sites, which are specific areas of forest biodiversity. The survey was conducted in South Korea within a distance of 50 m to the east, west, north and south from the core area where wind blows to the algific talus slopes. The study was conducted once or twice per season from April 2016 to November 2021. New information: Vascular plants of 25 algific talus slope sites in South Korea included a total of 1,052 taxa of 125 families, 486 genera, 947 species, 23 subspecies, 75 variety and 7 forma. The maximum surveyed area was 0.09 km2, accounting for only 0.00014% of the 62,860 km2 forest area in Korea, but comprise 22.27% of the 4,724 species of vascular plants in Korea. The algific talus slopes are areas rich in forest biodiversity. Six taxa were categorized as endangered, including Paeoniaobovata Maxim. Sixty-seven taxa, including Astilboidestabularis (Hemsl.) Engl.; 58 taxa endemic to the Korean Peninsula, including Weigelasubsessilis (Nakai) L.H. Bailey; and 317 taxa of floristic target plants were categorized as rare plants in the Red list. Further, 181 taxa were identified as northern lineage plants and 32 taxa, including Sillaphytonpodagraria (H. Boissieu) Pimenov, were limestone area plants. Regarding alien plants, 75 taxa, including Oenotherabiennis L., were identified and the naturalization and urbanization rates were 7.13% and 12.12%, respectively. Plants specific to the phytogeography of the 25 algific talus slope sites in this study were Vacciniumvitis-idaea L., Rosakoreana Kom., SyringavillosaVahlsubsp.wolfii (C.K. Schneid.) Jin Y.Chen & D.Y. Hong, Lonicerachrysantha Turcz. ex Ledeb., Tephroserisflammea (Turcz. ex DC.) Holub, among others.

Floristic inventory and distribution characteristics of vascular plants in forest wetlands of South Korea.

This study surveyed the vascular flora present in 455 forest wetlands in South Korea to provide baseline data for conservation, management and monitoring and to support preparation for climate change. The survey period was from April 2015 to November 2019. The vascular flora of 455 forest wetlands were identified and were found to consist of 143 families, 582 genera, 1,246 species, 26 subsp., 104 var., 12 f. and 1,388 individual taxa. Eight taxa were identified as Grade II endangered wild plants, 220 taxa were identified as northern lineage plants of the Korean Peninsula, 66 taxa were endemic to the Korean Peninsula and 94 taxa were rare plants as designated by the Korea Forest Service. Amongst them, eight taxa were Critically Endangered species, 10 taxa were Endangered species, 31 taxa were Vulnerable species, 31 taxa were Least Concern species and 14 taxa were Data Deficient species. Further, 411 taxa were floristic target plants, of which 17 taxa were classified as grade V, 70 taxa as grade IV, 110 taxa as grade III, 90 taxa as grade II and 29 taxa as grade I. There were 64 invasive alien plant taxa. Eighteen of these species were classed as Widespread species, nine taxa were Serious Spread species, 13 taxa were Spread Risk species, 18 taxa were Spread Concern species and six taxa were Continuing Spread species. According to wetland preference, 152 taxa (11.0%) were obligate wetland plants, 138 taxa (9.9%) were facultative wetland plants and 177 (12.77%) taxa were facultative plants. Additionally, 198 taxa (14.3%) were facultative upland plants and 723 taxa (52.1%) were obligate upland plants.