This paper presents transformer-based self-starting boost converter architecture with low-power maximum power point tracking (MPPT) control for low-voltage thermoelectric generator applications. The ...minimum working voltage of the proposed boost converter is 40 mV with oscillation through a positive feedback loop formed by a native MOS and transformer. The oscillation autonomously starts up by thermal noise and V OUT is charged up to 1.2 V by the oscillation so that the control block can operate. After that, the transformer for start-up is reused as an inductor, and the normal boost converter mode is enabled for better energy transfer efficiency. An improved MPPT sensing method is also proposed to simplify the circuit. The prototype chip is implemented in a 0.13-μm CMOS process. It operates with an input voltage range of 40 mV to 300 mV and provides a maximum output power of 2.7 mW with a maximum efficiency of 61% at an output voltage of 2 V.
HfZrO x (HZO) materials exhibiting ferroelectricity in ultra-thin layers can be deposited in various ways. Specifically, in sputtered HZO layers, only weak ferroelectric switching with gradual ...transition and small remnant polarization (Pr) is demonstrated using conventional rapid thermal annealing at high temperatures of at least 750°C. Here we show that rapidly transited ferroelectric switching with a larger 2 Pr of 24μ C/cm 2 is achieved by introducing a high pressure annealing (HPA) at even lower temperature of 550 °C. Our findings reveal that the HPA enhances the crystallinity of grains in the HZO, thereby enlarging the Pr and strengthening breakdown conditions. Through short pulse techniques, how interface and bulk region in the HZO are involved in the switching depending on the HPA is also investigated.
Clustering of high‐aspect‐ratio micropillars is a common phenomenon in nature, and has been utilized to build complex and large‐scale microarchitectures. To induce the clustering, the micropillars ...should be prepared to be metastable, so that they cluster under perturbation, such as the drying of water. Consequently, once micropillars cluster, they cannot de‐cluster spontaneously. This article shows that the micropillars of thermo‐responsive hydrogels can cluster and de‐cluster spontaneously and reversibly by changing the temperature. This behavior is called clustering transition. When the temperature is low, the micropillars swell and become soft. When the temperature is high, the micropillars de‐swell and become stiff. This phase transition alters the lowest energy state of the system, resulting in a reversible clustering transition. To demonstrate, high‐aspect‐ratio micropillars of poly(N‐isopropylacrylamide‐co‐acrylamide) hydrogels are fabricated through a soft‐molding technique. The micropillars show the clustering transition, and the behavior is studied using a thermodynamic model. By controlling the temperature, the micropillars grip and release microparticles on‐demand.
An array of micropillars made of thermo‐responsive hydrogels spontaneously cluster and de‐cluster depending on the temperature. Such a clustering transition is reversible as each state is energetically stable. The clustering transition is understood by using a thermodynamic model.
A crossbar array architecture employing resistive switching memory (RRAM) as a synaptic element accelerates vector-matrix multiplication in a parallel fashion, enabling energy-efficient pattern ...recognition. To implement the function of the synapse in the RRAM, multilevel resistance states are required. More importantly, a large on/off ratio of the RRAM should be preferentially obtained to ensure a reasonable margin between each state taking into account the inevitable variability caused by the inherent switching mechanism. The on/off ratio is basically adjusted in two ways by modulating measurement conditions such as compliance current or voltage pulses modulation. The latter technique is not only more suitable for practical systems, but also can achieve multiple states in low current range. However, at the expense of applying a high negative voltage aimed at enlarging the on/off ratio, a breakdown of the RRAM occurs unexpectedly. This stuck-at-short fault of the RRAM adversely affects the recognition process based on reading and judging each column current changed by the multiplication of the input voltage and resistance of the RRAM in the array, degrading the accuracy. To address this challenge, we introduce a boost-factor adjustment technique as a fault-tolerant scheme based on simple circuitry that eliminates the additional process to identify specific locations of the failed RRAMs in the array. Spectre circuit simulation is performed to verify the effect of the scheme on Modified National Institute of Standards and Technology dataset using convolutional neural networks in non-ideal crossbar arrays, where experimentally observed imperfective RRAMs are configured. Our results show that the recognition accuracy can be maintained similar to the ideal case because the interruption of the failure is suppressed by the scheme.
Butyrate is a bacterial metabolite of dietary fiber in the colon that has been used to treat inflammatory disease. However, the effect of oral supplementation with butyrate on colitis has not been ...fully explored. We evaluated the effects of and mechanisms underlying oral supplementation with butyrate on experimental murine colitis. In an in vitro study, we found that LPS induced the secretion of cytokines (i.e., IL-8 in COLO 205; TNF-α, IL-6, IL-12, and IL-10 in RAW 264.7; and TNF-α, IL-6 and IL-12 in peritoneal macrophages obtained from IL-10-deficient IL-10−/− mice). Butyrate (100μM and 500μM) inhibited pro-inflammatory cytokine production (i.e., IL-8 in COLO205 and TNF-α, IL-6 and IL-12 in macrophages) but promoted anti-inflammatory cytokine (i.e., IL-10) production in RAW264.7 cells. Butyrate attenuated both the LPS-induced degradation/phosphorylation of IκBα and DNA binding of NF-κB and enhanced histone H3 acetylation. To confirm that butyrate played a protective role in colitis, an acute colitis model was induced using dextran sulfate sodium (DSS) and a chronic colitis model was induced in IL-10−/− mice. The administration of oral butyrate (100mg/kg) significantly improved histological scores in both colitis models, including the IL-10−/− mice. In immunohistochemical staining, IκBα phosphorylation was attenuated, and histone H3 acetylation was reversed in the treated colons of both colitis models. Our results indicate that oral supplementation with butyrate attenuates experimental murine colitis by blocking NF-κB signaling and reverses histone acetylation. These anti-colitic effects of butyrate were IL-10-independent. Butyrate may therefore be a therapeutic agent for colitis.
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•Butyrate inhibits the production of TNF-α, IL-6 and IL-12 in macrophages.•Butyrate inhibits NF-κB signaling and histone deacetylation in IEC and macrophages.•Oral supplementation with butyrate suppressed colitis, even in IL-10−/− mice.•Butyrate attenuated IκBα phosphorylation and histone H3 deacetylation in the colon.•The anti-inflammatory effect of butyrate is IL-10 independent.
Background
Former cigarette smokers are at risk of developing ulcerative colitis (UC). However, the impact of smoking behavior on the occurrence of UC according to the amount smoked remains elusive. ...We aimed to determine the relationship between smoking behavior and the risk of UC development.
Methods
We conducted a retrospective population-based cohort study using the National Health Insurance Service database in South Korea. From January 2009 to December 2012, 23,235,771 individuals over 18 years of age who underwent a national health examination were enrolled and followed until 2016. All study participants were divided into the following 3 groups: nonsmokers, former smokers, and current smokers. The primary endpoint was newly developed UC.
Results
Compared with nonsmokers, the risk of UC development was significantly higher in former smokers adjusted hazard ratio (aHR) 1.83; 95% confidence interval (CI) 1.73–1.95 but significantly lower in current smokers (aHR 0.92; 95% CI 0.87–0.98). Among current smokers, individuals who stopped smoking after the baseline evaluation had a significantly higher risk of UC development than those who continued to smoke (aHR 2.42; 95% CI 2.10–2.80). The risk of UC development among former smokers was significantly associated with smoking amount and duration. Among current smokers, however, the risk of UC development was not correlated with the cumulative lifetime smoking exposure. The preventive effect of current smoking on UC development was observed only in men (aHR 0.90; 95% CI 0.84–0.96).
Conclusions
Compared with nonsmokers, former smokers have a significantly higher risk of UC development that may be proportional to the cumulative smoking exposure.
Background Although conventional endoscopy is a good diagnostic tool to evaluate tumor depth (T staging) in early gastric cancer (EGC), its accuracy has not been determined and no consensus has been ...reached regarding standard endoscopic criteria. Objective To evaluate the diagnostic accuracy of endoscopic T staging and to identify the characteristic endoscopic features for mucosal (T1m) and submucosal (T1sm) tumors. Design Retrospective study. Patients A consecutive 2105 patients with EGC who underwent either surgical (n = 1624) or endoscopic (n = 481) resection. Intervention Endoscopic staging was performed by consensus of 2 endoscopists based on the characteristic endoscopic criteria of T1m (smooth surface protrusion or depression, slight marginal elevation, and the smooth tapering of converging folds) and T1sm (irregular surface, marked marginal elevation, and clubbing/abrupt cutting/fusion of converging folds). The endoscopic staging was compared with the pathologic staging of the resected specimen. Results The overall accuracy of endoscopic staging was 78.0% (1642/2105). The sensitivity, specificity, and positive and negative predictive values of T1m endoscopic staging were 85.5%, 73.9%, 82.0%, and 78.5%, whereas those for T1sm were 72.6%, 81.9%, 71.9%, and 82.4%, respectively. Limitations Retrospective study. Endoscopic predictions for T1sm tumors were correct in only 72% of cases. Conclusions Conventional endoscopy was found to provide reliable accuracy for T staging in EGC and may be an effective method for assessing penetration depth. A detailed endoscopic evaluation regarding tumor base, margin, and converging folds may provide useful information to determine tumor depth and to select the optimal therapeutic strategy, particularly for endoscopic resection.
The explosive growth of data and information has motivated technological developments in computing systems that utilize them for efficiently discovering patterns and gaining relevant insights. ...Inspired by the structure and functions of biological synapses and neurons in the brain, neural network algorithms that can realize highly parallel computations have been implemented on conventional silicon transistor‐based hardware. However, synapses composed of multiple transistors allow only binary information to be stored, and processing such digital states through complicated silicon neuron circuits makes low‐power and low‐latency computing difficult. Therefore, the attractiveness of the emerging memories and switches for synaptic and neuronal elements, respectively, in implementing neuromorphic systems, which are suitable for performing energy‐efficient cognitive functions and recognition, is discussed herein. Based on a literature survey, recent progress concerning memories shows that novel strategies related to materials and device engineering to mitigate challenges are presented to primarily achieve nonvolatile analog synaptic characteristics. Attempts to emulate the role of the neuron in various ways using compact switches and volatile memories are also discussed. It is hoped that this review will help direct future interdisciplinary research on device, circuit, and architecture levels of neuromorphic systems.
Inspired by the structure and functions of biological synapses and neurons in the brain, neural network algorithms that can realize highly parallel computations are implemented in hardware. Herein, recent advances in emerging neuromorphic device technologies are presented in terms of novel strategies related to materials and device engineering to emulate nonvolatile analog synaptic and compact neuronal behaviors.
We investigated whether the response to anti-tumor necrosis factor (anti-TNF) treatment varied according to inflammatory tissue characteristics in Crohn’s disease (CD). Bulk RNA sequencing (RNA-seq) ...data were obtained from inflamed and non-inflamed tissues from 170 patients with CD. The samples were clustered based on gene expression profiles using principal coordinate analysis (PCA). Cellular heterogeneity was inferred using CiberSortx, with bulk RNA-seq data. The PCA results displayed two clusters of CD-inflamed samples: one close to (Inflamed_1) and the other far away (Inflamed_2) from the non-inflamed samples. Inflamed_1 was rich in anti-TNF durable responders (DRs), and Inflamed_2 was enriched in non-durable responders (NDRs). The CiberSortx results showed that the cell fraction of activated fibroblasts was six times higher in Inflamed_2 than in Inflamed_1. Validation with public gene expression datasets (GSE16879) revealed that the activated fibroblasts were enriched in NDRs over Next, we used DRs by 1.9 times pre-treatment and 7.5 times after treatment. Fibroblast activation protein (FAP) was overexpressed in the Inflamed_2 and was also overexpressed in the NDRs in both the RISK and GSE16879 datasets. The activation of fibroblasts may play a role in resistance to anti-TNF therapy. Characterizing fibroblasts in inflamed tissues at diagnosis may help to identify patients who are likely to respond to anti-TNF therapy.
In this paper, we present the results of a preliminary study on the self-powered autonomous wireless sensor node by using thermoelectric energy generator based on Silicon (Si) thermoelectric legs, ...energy management integrated circuit (EMIC), Radio Frequency (RF) module with a temperature and humidity sensor, etc. A novel thermoelectric module structure is designed as an energy generator module, which consists of 127 pairs of Silicon legs and this module is fabricated and tested to demonstrate the feasibility of generating electrical power under the temperature gradient of 70K. EMIC has three key features besides high efficiency, which are maximum power point tracking (MPPT), cold start, and complete self-power operation. EMIC achieved a cold start voltage of 200 mV, peak efficiency of 78.7%, MPPT efficiency 99.4%, and an output power of 34 mW through only the Thermoelectric Generator (TEG) source. To assess the capability of the device as a small scale power source for internet of things (IoT) service, we also tested energy conversion and storage experiments. Finally, the proposed sensor node system which can transmit and monitor the information from the temperature and humidity sensor through the RF module in real time demonstrates the feasibility for variable applications.
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