Medium Access Control (MAC) protocols determine how multiple devices share a single communication channel. This started from the ALOHA protocol and evolved to the Carrier Sense Multiple Access (CSMA) protocol used in WiFi. Protocols have been generally divided into contention-based methods like ALOHA and CSMA, which are simple but have collisions at high traffic loads, and contention-free methods like Time Division Multiple Access (TDMA), which offer high efficiency but require complex clock synchronization and inflexible time slotting. While distributed queuing concepts have been proposed to help bridge this gap (e.g., DQDB or DQRAP) they have traditionally relied on physical time slots, dual buses, or complex signaling that makes them less suitable for modern demands of wireless networks.

Professor Jin Nam and colleagues from the University of California, Riverside have developed novel synthesize piezoelectric scaffolds that can be remotely activated without a physically connected electrical wire to produce optimal electric fields in vivo for enhanced nerve regeneration. The technology works by using a biocompatible nanofibrous scaffold with a mesh-like structure that mimics the body’s natural tissue architecture and is made from piezoelectric materials. This technology allows for the mechano-electrical stimulation (MES) on endogenous or transplanted stem cells to enhance their neural differentiation/maturation. This technology is advantageous because this scaffold can be applied as a conduit or patch and activated remotely and non-invasively.  Fig 1: In vivo characterization of piezoelectric conduits and their impact on sciatic nerve regeneration. (a) A photo showing the transplantation of the P(VDF-TrFE) conduit into the rat to bridge the sciatic nerve gap. (b) Shockwave magnitude-dependent voltage outputs from P(VDF-TrFE) conduits. (c) A zoomed-in voltage output graph showing the  generation of 200 mVp-p under the 4-bar pressure of the shockwave actuation. (d, e) Large-field-of-view immunofluorescence images showing the entire structure of P(VDF-TrFE) conduit and ingrowth tissue, bridging transected sciatic nerve in (d) static and (e) MES conditions (NF200: axonal marker NF200; S1-S4 denote each of the 4 rats in the static group while MES1-MES4 denote each of the 4 rats from the MES group).

Researchers at the University of California, Davis have developed a solid-state X-ray imager with high temporal resolution.

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Historically, radio frequency and microwave switches have historically relied on either electromechanical switches (which suffer from limited speed and reliability) or solid-state switches such as PIN diodes and field-effect transistors (FETs), both of which require continuous bias current to maintain their states, consuming significant power in modern communication systems. In particular, solid-state switches (PIN diodes and FETs) require continuous DC power to maintain their ON or OFF states, leading to substantial energy consumption particularly problematic for battery-operated devices and large-scale systems like 5G/6G base stations and Internet of Things networks. Emerging non-volatile RF switches based on phase-change materials (PCM) and other memristive devices have shown promise but are constrained by large switching energies, limited resistance modulation ratios (typically < three orders of magnitude), volatile behavior requiring thermal maintenance above transition temperatures, and low endurance.

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