Although many hypo-pigmenting agents are currently available, the demand for novel whitening agents is increasing, in part due to the weak effectiveness and unwanted side effects of currently available compounds. To screen for novel hypo-pigmenting agents, many methodologies such as cell culture and enzymatic assays are routinely used. However, these models have disadvantages in terms of physiological and economic relevance. In this study, we validated zebrafish as a whole-animal model for phenotype-based screening of melanogenic inhibitors or stimulators. We used both the well-known melanogenic inhibitors (1-phenyl-2-thiourea, arbutin, kojic acid, 2-mercaptobenzothiazole) and newly developed small molecule compounds (haginin, YT16i). All the tested compounds produced inhibitory effects on the pigmentation of zebrafish, most likely due to their inhibitory potential on tyrosinase activity. In simultaneous in vivo toxicity tests, a newly developed melanogenic inhibitor YT16i showed massive abnormalities in terms of deformed morphologies and cardiac function. Together, these results provide a rationale in screening and evaluating the putative melanogenic regulatory compounds. We suggest that the zebrafish system is a novel alternative to mammalian models, with several advantages including the rapidity, cost-effectiveness, and physiological relevance.

No abstract

Flash memory is a promising candidate for use in in‐memory computing (IMC) owing to its multistate operations, high on/off ratio, non‐volatility, and the maturity of device technologies. However, its high operation voltage, slow operation speed, and string array structure severely degrade the energy efficiency of IMC. To address these challenges, a novel negative capacitance‐flash (NC‐flash) memory‐based IMC architecture is proposed. To stabilize and utilize the negative capacitance (NC) effect, a HfO2‐based reversible single‐domain ferroelectric (RSFE) layer is developed by coupling the flexoelectric and surface effects, which generates a large internal field and surface polarization pinning. Furthermore, NC‐flash memory is demonstrated for the first time by introducing a RSFE and dielectric heterostructure layer in which the NC effect is stabilized as a blocking layer. Consequently, an energy‐efficient and high‐throughput IMC is successfully demonstrated using an AND flash‐like cell arrangement and source‐follower/charge‐sharing vector‐matrix multiplication operation on a high‐performance NC‐flash memory.

Ferroelectric field-effect transistors (FeFETs) have attracted enormous attention for low-power and high-density nonvolatile memory devices in processing-inmemory (PIM). However, their small memory window (MW) and limited endurance severely degrade the area efficiency and reliability of PIM devices. Herein, we overcome such challenges using key approaches covering from the material to the device and array architecture. High ferroelectricity was successfully demonstrated considering the thermodynamics and kinetics, even in a relatively thick (≥30 nm) ferroelectric material that was unexplored so far. Moreover, we employed a metal−ferroelectric−metal− insulator−semiconductor architecture that enabled desirable voltage division between the ferroelectric and the metal−oxide−semiconductor FET, leading to a large MW (∼11 V), fast operation speed (<20 ns), and high endurance (∼10 11 cycles) characteristics. Subsequently, reliable and energy-efficient multiply-and-accumulation (MAC) operations were verified using a fabricated FeFET-PIM array. Furthermore, a system-level simulation demonstrated the high energy efficiency of the FeFET-PIM array, which was attributed to charge-domain computing. Finally, the proposed signed weight MAC computation achieved high accuracy on the CIFAR-10 dataset using the VGG-8 network.

No abstract

No abstract

The ferroelectric field-effect transistor (FeFET) is one of the most promising candidates for emerging nonvolatile memory devices owing to its low write energy and high ION/IOFF ratio. For FeFET applications as nonvolatile memory devices, 1FeFET, 1T-1FeFET, 2T-1FeFET, and 3T-1FeFET cells have been proposed. The 1FeFET cell exhibits the highest density but suffers from write disturbance. Although the 1T-1FeFET and 2T-1FeFET cells resolve the write disturbance, they use a write scheme with a negative write voltage (VW), which requires voltage swings of many control signals, leading to a significantly high write energy consumption. The 3T-1FeFET cell uses a write scheme without a negative VW; however, it exhibits the largest area overhead. Although the 1T-1FeFET cell resolves the write disturbance with a small area overhead; however, it exhibits high write energy consumption because of the use of a negative VW. In this paper, to significantly reduce the write energy consumption, we propose a less control signal swing (LCSS) write scheme without using a negative VW. Simulation results indicate that the worst, average, and best cases of the proposed LCSS write scheme can achieve 35%, 66%, and 96% lower write energy consumption, respectively, than the write scheme with a negative VW in the 1T-1FeFET cell. We also identify the available sensing schemes for each FeFET cell in the read operation according to the FeFET threshold voltage distribution.

No abstract