8Mb/s 28Mb/mJ robust true-random-number generator in 65nm CMOS based on differential ring oscillator with feedback resistors

On-chip true random number generators (TRNG) have been gaining attention as an important component for building secure systems [1]. CMOS TRNGs typically exploit device-level noise, such as thermal or flicker noise to generate random bits [2]. Among various types of CMOS TRNGs, the meta-stability-based TRNG is known to have very high throughput for random bit generation, but it requires sophisticated control and calibration circuits to suppress bias [6]. Another popular type is the ring oscillator (RO)-based TRNG, which utilizes timing jitter [1-5]. Relatively simple circuits make it an attractive option, but there remains a need to improve the tolerance against power supply attacks and process/environmental variations [3]. Recently, selective use of a certain set of inverter chains based on pre-tuning was proposed to mitigate process variation effects [2].1

Mechanically resilient, alumina-reinforced carbon nanotube arrays for in-plane shock absorption in micromechanical devices

Abstract Microelectromechanical systems (MEMS) are of considerable interest due to their compact size and low power consumption when used in modern electronics. MEMS devices intrinsically incorporate three-dimensional (3D) microstructures for their intended operations; however, these microstructures are easily broken by mechanical shocks accompanying high-magnitude transient acceleration, inducing device malfunction. Although various structural designs and materials have been proposed to overcome this limit, developing a shock absorber for easy integration into existing MEMS structures that effectively dissipates impact energy remains challenging. Here, a vertically aligned 3D nanocomposite based on ceramic-reinforced carbon nanotube (CNT) arrays is presented for in-plane shock-absorbing and energy dissipation around MEMS devices. This geometrically aligned composite consists of regionally-selective integrated CNT arrays and a subsequent atomically thick alumina layer coating, which serve as structural and reinforcing materials, respectively. The nanocomposite is integrated with the microstructure through a batch-fabrication process and remarkably improves the in-plane shock reliability of a designed movable structure over a wide acceleration range (0–12,000g). In addition, the enhanced shock reliability through the nanocomposite was experimentally verified through comparison with various control devices

BitBlade: Energy-Efficient Variable Bit-Precision Hardware Accelerator for Quantized Neural Networks

IEEEWe introduce an area/energy-efficient precisionscalable neural network accelerator architecture. Previous precision-scalable hardware accelerators have limitations such as the under-utilization of multipliers for low bit-width operations and the large area overhead to support various bit precisions. To mitigate the problems, we first propose a bitwise summation, which reduces the area overhead for the bit-width scaling. In addition, we present a channel-wise aligning scheme (CAS) to efficiently fetch inputs and weights from on-chip SRAM buffers and a channel-first and pixel-last tiling (CFPL) scheme to maximize the utilization of multipliers on various kernel sizes. A test chip was implemented in 28-nm CMOS technology, and the experimental results show that the throughput and energy efficiency of our chip are up to 7.7x and 1.64x higher than those of the state-of-the-art designs, respectively. Moreover, additional 1.5-3.4x throughput gains can be achieved using the CFPL method compared to the CAS.N

Ionic Liquid Electrolytes for Electrochemical Energy Storage Devices

For decades, improvements in electrolytes and electrodes have driven the development of electrochemical energy storage devices. Generally, electrodes and electrolytes should not be developed separately due to the importance of the interaction at their interface. The energy storage ability and safety of energy storage devices are in fact determined by the arrangement of ions and electrons between the electrode and the electrolyte. In this paper, the physicochemical and electrochemical properties of lithium-ion batteries and supercapacitors using ionic liquids (ILs) as an electrolyte are reviewed. Additionally, the energy storage device ILs developed over the last decade are introduced

Pyruvate Kinase M2 Accelerates Cutaneous Wound Healing via Glycolysis and Wnt/β-Catenin Signaling

Cutaneous wound healing is a complex and dynamic process with high energy demand. The activation of glycolysis is essential for restoring the structure and function of injured tissues in wounds. Pyruvate kinase M2 (PKM2) is an enzyme that plays a crucial role in the last step of glycolysis. PKM2-mediated glycolysis is known to play an important role in diseases related to regeneration and inflammation. However, the role of PKM2 in wound healing has not been fully elucidated. In this study, we found that PKM2 expression and pyruvate kinase (PK) activity were increased with the activation of Wnt/β-catenin signaling during wound healing in mice. TEPP-46, an allosteric activator of PKM2, enhanced HaCaT human keratinocyte migration and cutaneous wound healing with an increment of PK activity. Moreover, we confirmed the effect of co-treatment with TEPP-46 and KY19382, a Wnt/β-catenin signaling activator through the interference with the CXXC-type zinc finger protein 5 (CXXC5) Dishevelled interaction, on wound healing. The combination treatment significantly accelerated wound healing, which was confirmed by the expression level of PCNA, keratin 14, and α-SMA. Furthermore, co-treatment induced angiogenesis in the wound beds. Overall, activation of both glycolysis and Wnt/β-catenin signaling has the potential to be used as a therapeutic approach for wound healing

Behavioral and Disease-Related Characteristics of Patients with Acute Stroke during the Coronavirus Disease Pandemic

This study aimed to evaluate the behavioral and disease-related characteristics of patients with acute stroke during the Coronavirus disease (COVID-19) pandemic. This retrospective study was conducted using the Korean Stroke Registry database from a single cerebrovascular specialty hospital. We categorized the COVID-19 pandemic (February 2020 to June 2021) into three waves according to the number of COVID-19 cases recorded and the subjective fear index of the general population and matched them with the corresponding pre-COVID-19 (January 2019 to January 2020) periods. The total number of acute stroke hospitalizations during the pre-COVID-19 and COVID-19 periods was 402 and 379, respectively. The number of acute stroke hospitalizations recorded during the regional outbreak of COVID-19 was higher than that recorded during the corresponding pre-COVID-19 period (97 vs. 80). Length of hospital stay was significantly longer during the COVID-19 pandemic than during the pre-COVID-19 period (11.1 and 8.5 days, respectively; p = 0.003). There were no significant differences in the time from onset to hospital arrival, rate of acute intravenous/intra-arterial (IV/IA) treatments, and door-to-IV/IA times between the pre-COVID-19 and COVID-19 periods. This study suggests that specialty hospitals can effectively maintain the quality of healthcare through the management of acute time-dependent diseases, even during pandemics

Comparison of the air change per hour measured over four seasons in the residential buildings of the urban, rural, and industrial areas of South Korea: K-IOP Study

Air infiltration, calcuated by air changes per hour (ACH) is a key factor in assessing the potential amount of air borne pollutants moving from outdoor into indoor spaces. We measured the natural ACH through fall, winter, spring, and summer (2 weeks/season), in 81 nonsmoking elderly houses located in urban (n = 29), industrial (n = 26) and rural (n = 26) areas from 2021 to 2022 consecutively. Indoor CO2 data measured at dawn (01:00 to 05:00 a.m.) over four season was used to estimate the ACH. Moreover, morning ACHs were also calculated from the CO2 level monitored in the morning, when the levels were dropped significantly with opening a window during fall, winter, and spring. The ACH at dawn over the four seasons ranged from 0.02 to 0.03,while that in the morning with opening a window was 0.2 to 0.3. Our multivariate regression models demonstrated that the difference in CO2 concentration during dawn was positively associated with the ACH change after adjusting for seasonality. In addition, after controlling for the study area, ACH was approximately 50 % higher during summer than during the other seasons (p < 0.05). This study elucidates the seasonal and regional distributions of ACH; a determination of these patterns may further contribute to future simulation or prediction studies assessing the associations among indoor air quality, activity patterns and ventilation practices among Korean elderly population

Behavioral and Disease-Related Characteristics of Patients with Acute Stroke during the Coronavirus Disease Pandemic

This study aimed to evaluate the behavioral and disease-related characteristics of patients with acute stroke during the Coronavirus disease (COVID-19) pandemic. This retrospective study was conducted using the Korean Stroke Registry database from a single cerebrovascular specialty hospital. We categorized the COVID-19 pandemic (February 2020 to June 2021) into three waves according to the number of COVID-19 cases recorded and the subjective fear index of the general population and matched them with the corresponding pre-COVID-19 (January 2019 to January 2020) periods. The total number of acute stroke hospitalizations during the pre-COVID-19 and COVID-19 periods was 402 and 379, respectively. The number of acute stroke hospitalizations recorded during the regional outbreak of COVID-19 was higher than that recorded during the corresponding pre-COVID-19 period (97 vs. 80). Length of hospital stay was significantly longer during the COVID-19 pandemic than during the pre-COVID-19 period (11.1 and 8.5 days, respectively; p = 0.003). There were no significant differences in the time from onset to hospital arrival, rate of acute intravenous/intra-arterial (IV/IA) treatments, and door-to-IV/IA times between the pre-COVID-19 and COVID-19 periods. This study suggests that specialty hospitals can effectively maintain the quality of healthcare through the management of acute time-dependent diseases, even during pandemics

Azaquinoid‐Based High Spin Open‐Shell Conjugated Polymer for n‐Type Organic Field‐Effect Transistors

Abstract An open‐shell quinoidal conjugated polymer exhibiting n‐type semiconducting behavior is successfully synthesized and characterized. An electron‐deficient azaaromatic unit is proven to reduce the energy levels of frontier orbitals via the electronegative nitrogen atom and steric hindrance within the polymer backbone. A synthesized azaquinoidal bithiophene (azaQuBT) is a quinoidal bithiophene that is end‐functionalized with a pyridine ring. The open‐shell quinodial conjugated polymer, poly(azaquinoidal bithiophene‐thiophene), PazaQuBT‐T, is synthesized using azaQuBT and thiophene. The extended quinoidal building block, which has an open‐shell diradical character, induces low bandgaps, redox amphoterism, and high‐spin‐induced paramagnetic behavior of the resulting polymer. PazaQuBT‐T achieves ambipolar charge‐transport behavior in organic field‐effect transistor (OFET) devices. Through a PEIE treatment onto the contact electrode, PazaQuBT‐based OFETs exhibit unipolar n‐channel operation with electron mobility up to 0.98 cm2 V−1 s−1. This work demonstrates the development of novel open‐shell conjugated polymers with high‐spin characteristics and n‐type semiconducting property