The development of high performance and cost-effective electrode materials is the main challenge for the commercialization of sodium ion batteries. Here, we suggest a substantial iron-doped sodium ...vanadium fluorophosphate and sodium vanadium phosphate composite as a promising cathode. Iron substitution enhances ionic diffusivity and lowers the bandgap, and, thus, improves sodium storage performance. The origin of the enhanced performance is investigated employing
in situ
X-ray diffraction,
ex situ
X-ray photoelectron spectroscopy, density functional theory calculation, and electrochemical characterization. Moreover, we demonstrate its full cell configuration with earth-abundant element-based copper sulfide anodes. The suggested cathode and sodium ion battery full cell exhibits well-balanced sodium storage performance in terms of energy density, C-rate capability, cycling stability, and low cost. The low cost and high performance of the full cell make it an attractive choice for energy storage systems and high power applications to support lithium ion batteries.
Substantial Fe substitution into a vanadium-based NASICON cathode is demonstrated to boost a cathode performance and materialize a superior sodium ion battery.
The deployment of LoRaWAN on the Internet of Things (IoT) has increased since its advent and LoRaWAN now predominates the IoT market over other Low Powered Wide Area Networks (LPWAN). However, since ...LoRaWAN uses Chirp Spread Spectrum (CSS), it is susceptible to wideband jamming attacks. In this paper, we demonstrate with experiments and concrete numerical results that jamming US915 LoRaWAN frequency is possible by the usual data transmission and reception process of 900MHz Canopy, one of the legacy 900MHz network device. Intentional attack is possible in the same manner. The experiments emulate the real-world environment operated in medical and agriculture industries, in outdoor and indoor conditions, respectively. In addition, this paper introduces and utilizes the novel metric, Jamming Effect (JE), that indicates the network performance of wireless networks that spread the data on air.
Binary metal sulfides have been explored as sodium storage materials owing to their high theoretical capacity and high stable cyclability. Nevertheless, their relative high charge voltage and ...relatively low practical capacity make them less attractive as an anode material. To resolve the problem, addition of alloying elements is considerable. Copper antimony sulfide is investigated as a representative case. In this study, we do not only perform electrochemical characterization on CuSbS2, but also investigate its nonequilibrium sodiation pathway employing in-/ex situ transmission electron microscopy, in situ X-ray diffraction, and density functional theory calculations. Our finding provides valuable insights on sodium storage into ternary metal sulfide including an alloying element.
Self-powered neutron detectors (SPNDs) are widely used in reactors to monitor neutron flux, while they have several advantages such as small size, and relatively simple electronics required in ...conjunction with those usages, they have some intrinsic problems of the low level of output current-a slow response time and the rapid change of sensitivity-that make it difficult to use for a long term. Monte Carlo simulation was used to calculate the escape probability as a function of the birth position of emitted beta particle for geometry of rhodium-based SPNDs. A simple numerical method calculated the initial generation rate of beta particles and the change of generation rate due to rhodium burnup. Using results of the simulation and the simple numerical method, the burnup profile of rhodium number density and the neutron sensitivity were calculated as a function of burnup time in reactors. This method was verified by the comparison of this and other papers, and data of YGN3.4 (Young Gwang Nuclear plant 3, 4) about the initial sensitivity. In addition, for improvement of some properties of rhodium-based SPNDs, which are currently used, a modified geometry is proposed. The proposed geometry, which is tube-type, is able to increase the initial sensitivity due to increase of the escape probability. The escape probability was calculated by changing the thickness of the insulator and compared solid-type with tube-type about each insulator thickness. The method used here can be applied to the analysis and design of other types of SPNDs.
A study on the sensitivity of self-powered neutron detector (SPND) Wanno Lee; Gyunseong Cho; Kwanghyun Kim ...
1999 IEEE Nuclear Science Symposium. Conference Record. 1999 Nuclear Science Symposium and Medical Imaging Conference (Cat. No.99CH37019),
1999, Letnik:
2
Conference Proceeding
Self-Powered Neutron Detectors (SPND) are widely used in reactors to monitor neutron flux. While they have several advantages such as small size, and relatively simple electronics required in ...conjunction with those usage, they have some intrinsic problems of the low level of output current, a slow response time, and the rapid change of sensitivity which makes it difficult to use for a long term. Monte Carlo simulation was used to calculate the escape probability as a function of the birth position of emitted beta particle for geometry of rhodium-based SPNDs. A simple numerical method calculated the initial generation rate of beta particles and the change of generation rate due to rhodium burn-up. Using the simulation result, the burn-up profile of rhodium number density and the neutron sensitivity were calculated as a function of burn-up time in reactors. In addition, for improvement of some properties of rhodium-based SPNDs which are currently used, a new material and modified geometry were proposed in this work. Ag/sup 109/ was chosen as a replacing material for rhodium. Also, this work compared the initial sensitivity of a solid type with its of a tube type.
The recent COVID-19 pandemic has been disrupting the daily lives of people across the world, causing a major concern for psychological well-being in children. This study aimed to examine (1) how life ...satisfaction and its potential predictors have been affected by the pandemic among school-aged children in Korea, and (2) which factors would predict their life satisfaction during the pandemic. We surveyed 166 fourth-graders in the Seoul metropolitan area to assess their psychological well-being and potentially related variables during the pandemic. The data were compared with those available from two pre-COVID-19 surveys, the 2018 Korean Children and Youth Panel Survey (
= 1236) and the 2019 Korean Children and Youth Well-being Index Survey (
= 334). Higher levels of stress were observed in children during the COVID-19 pandemic; however, the level of their life satisfaction remained unchanged when compared with data from the pre-COVID-19 surveys. The pandemic also affected peer relationship quality and susceptibility to smartphone addiction, but not perceived parenting style nor academic engagement. Interestingly, peer relationship quality no longer predicted life satisfaction during the pandemic; perceived parenting styles and parent-child conversation time predicted life satisfaction. The results suggest a central role of parent-child relationship in supporting the psychological well-being of school-aged children during the pandemic.
Ligand-conjugated liposomes are promising for the treatment of specific receptor-overexpressing cancers. However, previous studies have shown inconsistent results because of the varying properties of ...the ligand, presence of a polyethylene glycol (PEG) coating on the liposome, length of the linker, and density of the ligand.
Here, we prepared PEGylated liposomes using PEG-linkers of various lengths conjugated with folate and evaluated the effect of the PEG-linker length on the nanoparticle distribution and pharmacological efficacy of the encapsulated drug both in vitro and in vivo.
When folate was conjugated to the liposome surface, the cellular uptake efficiency in folate receptor overexpressed KB cells dramatically increased compared to that of the normal liposome. However, when comparing the effect of the PEG-linker length in vitro, no significant difference between the formulations was observed. In contrast, the level of tumor accumulation of particles in vivo significantly increased when the length of the PEG-linker was increased. The tumor size was reduced by >40% in the Dox/FL-10K-treated group compared to that in the Dox/FL-2K- or 5K-treated groups.
Our study suggests that as the length of PEG-linker increases, the tumor-targeting ability can be enhanced under in vivo conditions, which can lead to an increase in the antitumor activity of the encapsulated drug.
Fecal incontinence is a disabling condition in which the passage of fecal material cannot be controlled. Although the condition is not life-threatening, it can seriously reduce the quality of life of ...a patient by isolating them from others. Though various surgical treatments are available for moderate to severe symptoms, a bulking agent is a minimally invasive technique that has attracted attention because of its safety and simple treatment process. However, the biocompatibility of bulking agent materials remains a central issue, with their durability questioned because immune responses and/or the circulatory system may remove the bulking agent
in vivo
. This study investigated a bulking agent composed of polydimethylsiloxane and hyaluronic acid as a microfiller and carrier gel, respectively. To improve the injectability of the bulking agent, the filler size was tuned using a suspension-based fabrication technique. To evade immune responses, the filler surface was treated with a zwitterionic polymer that simultaneously functionalized and stabilized the material interfaces. The resulting bulking agent exhibited good injectability and biocompatibility
in vitro
, with 58% lower protein adsorption and no cytotoxicity, leading to an improved bulking effect in a preclinical rat model compared with a bulking agent without surface treatment. These results illustrate the promising potential of bulking agents as a therapy for fecal incontinence with reduced foreign body reactions and long-lasting efficacy.
The use of zwitterion-coated particulate silicone as a bulking agent for the treatment of fecal incontinence was investigated in a rat model.
Sorafenib, marketed under the brand name Nexavar®, is a multiple tyrosine kinase inhibitor drug that has been actively used in the clinical setting for the treatment of several cancers. However, the ...low solubility and bioavailability of sorafenib constitute a significant barrier to achieving a good therapeutic outcome. We developed a sorafenib-loaded self-nanoemulsifying drug delivery system (SNEDDS) formulation composed of capmul MCM, tween 80, and tetraglycol, and demonstrated that the SNEDDS formulation could improve drug solubility with excellent self-emulsification ability. Moreover, the sorafenib-loaded SNEDDS exhibited anticancer activity against Hep3B and KB cells, which are the most commonly used hepatocellular carcinoma and oral cancer cell lines, respectively. Subsequently, to improve the storage stability and to increase the possibility of commercialization, a solid SNEDDS for sorafenib was further developed through the spray drying method using Aerosil® 200 and PVP K 30. X-ray diffraction and differential scanning calorimeter data showed that the crystallinity of the drug was markedly reduced, and the dissolution rate of the drug was further improved in formulation in simulated gastric and intestinal fluid conditions. In vivo study, the bioavailability of the orally administered formulation increases dramatically compared to the free drug. Our results highlight the use of the solid-SNEDDS formulation to enhance sorafenib's bioavailability and outlines potential translational directions for oral drug development.
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