Gadolinium oxide nanocrystal ͑Gd 2 O 3 -NC͒ memories treated by postdeposition rapid thermal annealing were investigated. Bandgap offset performed by a crystallized Gd 2 O 3 -NC dot surrounded by amorphous Gd 2 O 3 dielectrics is successfully demonstrated and proven by the transmission electron microscopy images and electron diffraction pattern. The Gd 2 O 3 -NC memory exhibits a hysteresis memory window of 4 V and NC dot density of more than 8.5 ϫ 10 11 cm −2 . In addition, the formation of Gd 2 O 3 -NC and charge loss characteristics on annealing temperature were analyzed and optimized at 850°C. The data endurance of 10 4 program and erase cycling for a sufficient memory window ͑Ͼ2 V͒ was also observed for the Gd 2 O 3 nanocrystal memory.In order to scale down floating gate ͑FG͒ nonvolatile memory ͑NVM͒, tunnel oxide limitation for sufficient charge retention has to be overcome. 1 One way is to implement high-dielectric-constant ͑high-k͒ materials such as Al 2 O 3 thin film as the tunnel oxide for the reduction of operation voltage while satisfying the data retention and endurance. 2 The other is using a discrete charge-storage concept for thinner tunnel oxide without sacrificing nonvolatility. Isolated Si and Ge semiconductor nanocrystal ͑NC͒ memories are NVMs that have been demonstrated to have a more simplified fabrication process, better punchthrough effect, and immunity to oxide defects as compared to conventional FG NVMs. 1,3,4 To achieve the fast write/ erase and long retention time simultaneously, metal NC memories are presented to engineer the depth of the potential well at storage nodes. Heavy metals, 4-7 silicide, 8,9 nitrided-metal, 10 and metal-oxide 11,12 are NC memories used as storage nodes. Compared with the semiconductor NC memories, metal counterparts exhibit a higher density of states around the Fermi level, stronger coupling with the conduction channel, a wider range of available work functions, and smaller energy perturbation due to carrier confinement. 13 Gadolinium oxide ͑Gd 2 O 3 ͒, the rare-earth sesquioxides ͑R 2 O 3 ͒, has been reported to be candidates as gate dielectrics for silicon and compound semiconductor device applications. 14,15 They are demonstrated to exhibit three different structures such as cubic, monoclinic, and hexagonal under different growth temperatures. 16 In addition, a different energy bandgap of amorphous ͑6.3-6.4 eV͒ and crystallized ͑5.0-5.4 eV͒ Gd 2 O 3 thin films has also been discovered. 17,18 Recently, magnetic nanocrystalline Gd 2 O 3 particles embedded in silica glass have been proposed for memory applications. 19 In this work, we demonstrate that a crystallized gadolinium oxide with low bandgap acts as a charge-storage node when it is surrounded by amorphous gadolinium oxide with higher bandgap to form Gd 2 O 3 nanocrystal memories ͑Gd 2 O 3 -NC͒. This separate charge-storage structure is different from the previous research regarding NC memory devices, 4-12 and the tunnel oxide thickness is effectively increased for better charge retention. The memory...
Real world markets display power-law features in variables such as price fluctuations in stocks. To further understand market behavior, we have conducted a series of market experiments on our web-based prediction market platform which allows us to reconstruct transaction networks among traders. From these networks, we are able to record the degree of a trader, the size of a community of traders, the transaction time interval among traders and other variables that are of interest. The distributions of all these variables show power-law behavior. On the other hand, agent-based models have been proposed to study the properties of real financial markets. We here study the statistical properties of these agent-based models and compare them with the results from our web-based market experiments. In this work, three agentbased models are studied, namely, zero-intelligence (ZI), zero-intelligenceplus (ZIP) and Gjerstad-Dickhaut (GD). Computer simulations of variables based on these three agent-based models were carried out. We found that although being the most naive agent-based model, ZI indeed best describes the properties observed in real markets. Our study suggests that the basic ingredient to produce the observed properties from real world markets could in fact be the result of a continuously evolving dynamical system with basic features similar to the ZI model.
Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, are used to reduce cholesterol biosynthesis in the liver. Accordingly, statins regulate nitric oxide (NO) and glutamate metabolism, inflammation, angiogenesis, immunity and endothelial progenitor cells (EPCs) functions. The function of EPCs are regulated by stromal cell-derived factor 1 (SDF-1), vascular endothelial growth factor (VEGF), and transforming growth factor β (TGF-β), etc. Even though the pharmacologic mechanisms by which statins affect the neovasculogenesis of circulating EPCs, it is still unknown whether statins affect the EPCs function through the regulation of CXCR4, a SDF-1 receptor expression. Therefore, we desired to explore the effects of statins on CXCR4 expression in EPC-mediated neovascularization by in vitro and in vivo analyses. In animal studies, we analyzed the effects of atorvastatin or rosuvastatin treatments in recovery of capillary density and blood flow, the expression of vWF and CXCR4 at ischemia sites in hindlimb ischemia ICR mice. Additionally, we analyzed whether the atorvastatin or rosuvastatin treatments increased the mobilization, homing, and CXCR4 expression of EPCs in hindlimb ischemia ICR mice that underwent bone marrow transplantation. The results indicated that statins treatment led to significantly more CXCR4-positive endothelial progenitor cells incorporated into ischemic sites and in the blood compared with control mice. In vivo, we isolated human EPCs and analyzed the effect of statins treatment on the vasculogenic ability of EPCs and the expression of CXCR4. Compared with the control groups, the neovascularization ability of EPCs was significantly improved in the atorvastatin or rosuvastatin group; this improvement was dependent on CXCR4 up-regulation. The efficacy of statins on improving EPC neovascularization was related to the SDF-1α/CXCR4 axis and might be regulated by the NO. In conclusion, atorvastatin and rosuvastatin improved neovascularization in hindlimb ischemia mice; this effect may have been mediated by increased CXCR4 expression in EPCs.
Background Cardiovascular disease is the leading cause of morbidity and mortality in patients with end‐stage renal disease. Heart rhythm complexity analysis has been shown to be useful in predicting outcomes in various diseases; however, data on patients with end‐stage renal disease are limited. In this study, we analyzed the association between heart rhythm complexity and long‐term cardiovascular outcomes in patients with end‐stage renal disease receiving peritoneal dialysis. Methods and Results We prospectively enrolled 133 patients receiving peritoneal dialysis and analyzed linear heart rate variability and heart rhythm complexity variables including detrended fluctuation analysis ( DFA ) and multiscale entropy. The primary outcome was cardiovascular mortality, and the secondary outcome was the occurrence of major adverse cardiovascular events. After a median of 6.37 years of follow‐up, 21 patients (22%) died from cardiovascular causes. These patients had a significantly lower low‐frequency band of heart rate variability, low/high‐frequency band ratio, total power band of heart rate variability, heart rate turbulence slope, deceleration capacity, short‐term DFA (DFAα1); and multiscale entropy slopes 1 to 5, scale 5, area 1 to 5, and area 6 to 20 compared with the patients who did not die from cardiovascular causes. Time‐dependent receiver operating characteristic curve analysis showed that DFA α1 had the greatest discriminatory power for cardiovascular mortality (area under the curve: 0.763) and major adverse cardiovascular events (area under the curve: 0.730). The best cutoff value for DFA α1 was 0.98 to predict both cardiovascular mortality and major adverse cardiovascular events. Multivariate Cox regression analysis showed that DFA α1 (hazard ratio: 0.076; 95% CI , 0.016–0.366; P =0.001) and area 1 to 5 (hazard ratio: 0.645; 95% CI , 0.447–0.930; P =0.019) were significantly associated with cardiovascular mortality. Conclusions Heart rhythm complexity appears to be a promising noninvasive tool to predict long‐term cardiovascular outcomes in patients receiving peritoneal dialysis.
Integration of ammonia-plasma-functionalized graphene nanodiscs as charge trapping centers for nonvolatile memory applications. Carbon.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.