Lifeboat Foundation

Memristors with controllable resistive switching (RS) behavior have been considered as promising candidates for synaptic devices in next-generation neuromorphic computing. In this work, two-terminal memristors with controllable digital and analog RS behavior are fabricated based on two-dimensional (2D) WSe₂ nanosheets. Under a relatively high operating voltage of 4 V, the memristor demonstrates stable and reliable non-volatile bipolar digital RS with a high switching ratio of 6.3 × 10⁴. On the other hand, under a relatively low operation voltage, the memristor exhibits analog RS with a series of tunable resistance states. The fabricated memristors can work as an artificial synapse with fundamental synaptic functions, such as long-term potentiation (LTP) and depression (LTD) as well as paired-pulse facilitation (PPF). More importantly, the memristor demonstrates high conductance modulation linearity with the calculated nonlinear parameter for conductance as-0.82 in the LTP process, which is beneficial to improving the accuracy of neuromorphic computing. Furthermore, the neuromorphic computing of file types and image recognition can be emulated based on a constructed three-layer artificial neural network (ANN) with a recognition accuracy that can reach up to 95.9% for small digits. In addition, memristors can be used to emulate the learning-forgetting experience of the human brain. Consequently, the memristor based on 2D WSe₂ nanosheets not only exhibits controllable RS behavior but also simulates synaptic functions and is expected to be a potential candidate for future neuromorphic computing applications.

PubMed Disclaimer

Memristive devices with both electrically and optically induced synaptic dynamic behaviors will be crucial to the accomplishment of brain-inspired neuromorphic computing systems, in which the resistive materials and device architectures are two of the most important cornerstones, but still under challenge. Herein, kuramite Cu3SnS4 is newly introduced into poly-methacrylate as the switching medium to construct memristive devices, and the expected high-performance bio-mimicry of diverse optoelectronic synaptic plasticity is demonstrated. In addition to the excellent basic performances, such as stable bipolar resistive switching with On/Off ratio of ∼486, Set/Reset voltage of ∼-0.88/+0.96 V, and good retention feature of up to 104 s, the new designs of memristors possess not only the multi-level controllable resistive-switching memory property but also the capability of mimicking optoelectronic synaptic plasticity, including electrically and visible/near-infrared light-induced excitatory postsynaptic currents, short-/long-term memory, spike-timing-dependent plasticity, long-term plasticity/depression, short-term plasticity, paired-pulse facilitation, and “learning-forgetting-learning” behavior as well. Predictably, as a new class of switching medium material, such proposed kuramite-based artificial optoelectronic synaptic device has great potential to be applied to construct neuromorphic architectures in simulating human brain functions.

© 2023 Author(s). Published under an exclusive license by AIP Publishing.

PubMed Disclaimer

More than 3.5 billion years ago, life on Earth emerged from chemical reactions. Nature invented RNA, proteins, and DNA, the core molecules of life, and created the ribosome, a molecular factory that builds proteins from instructions in the genome.

Proteins are wondrous dynamic molecules with incredible functions—from molecular engines that power motion, to photosynthetic machines that capture light and convert it to energy, scaffolding that builds the internal skeletons of cells, complex sensors that interact with the environment, and information processing systems that run the programs and operating system of life. Proteins underlie disease and health, and many life-saving medicines are proteins.

Biology is the most advanced technology that has ever been created, far beyond anything that people have engineered. The ribosome is programmable—it takes the codes of proteins in the form of RNA and builds them up from scratch—fabrication at the atomic scale. Every cell in every organism on earth has thousands to millions of these molecular factories. But even the most sophisticated computational tools created to date barely scratch the surface: biology is written in a language we don’t yet understand.

The enzyme telomerase can prevent telomere attrition from happening by extending the length of telomeres. However, in most multicellular organisms, including humans, telomerase expression is switched off, except in germ cells, some types of stem cells, and certain white blood cells. While this might play a role in preventing cancer, as most cancerous cells must switch telomerase expression back on via mutations to enable runaway replication, numerous studies have shown that increasing telomerase through TERT delays aging and increases longevity of model organisms [1].

The small molecule that could

In the lab, this is usually done by introducing genetic vectors carrying a working copy of the gene that codes TERT. It’s this gene that is switched off in somatic cells. However, gene therapies are complex and expensive, and they are just entering the medical mainstream. What if we could do the same using a small molecule?

The best supercomputers in the world have less than 50,000 GPUs, how in the world is someone going to make an AI cluster with 1.2 million GPUs?

SpaceX was back at the launch pad Sunday with an updated rocket to finish off a Starlink mission it tried to send up earlier this month.

A Falcon 9 on the Starlink 10–2 mission lifted off at 1:15 p.m. from Cape Canaveral Space Force Station’s Space Launch Complex 40 amid cloudy skies with 22 more Starlink satellites for the company’s growing internet constellation that now numbers more than 6,100 satellites in orbit.

The launch came nine days since SpaceX last attempted to knock out the mission on June 14. That attempt had a rare scrub as the countdown clock reached 0 and the rocket was ultimately brought back from the pad to allow for last week’s ASTRA 1P satellite launch to go up instead.

Best seen with the naked eye or a pair of binoculars, delicate NLCs are visible at this time of year because they’re being lit by the sun, which sets yet never gets far below the horizon.

Ideally placed in the night sky this month is M13, the “Great Globular Cluster in Hercules.” A spectacular sight in binoculars or a small telescope, the closest and the brightest globular cluster—as seen from the northern hemisphere—is about 25,000 light-years distant.

Beneath the Antarctic ice, scientists find remnants of a giant river system that flowed for thousands of miles.

By Kristel Tjandra & LiveScience

Geologists digging into the massive ice sheet of West Antarctica have discovered the remains of an ancient river system that once flowed for nearly a thousand miles.

Perseverance rover recently arrived at Bright Angel, a notable site on Mars distinguished by its light-toned rocks, situated at the edge of the ancient Neretva Vallis river channel.

Last week, NASA ’s Perseverance Mars rover arrived at the long-awaited site of Bright Angel, named for being a light-toned rock that stands out in orbital data. The unique color here, as well as the surface characteristics and location on the edge of the ancient river channel Neretva Vallis, made Bright Angel a location of interest for the Mars 2020 Science Team.

Initial Observations and Data Collection.