124 research outputs found

    Qi standard metasurface for free-positioning and multi-device supportive wireless power transfer

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    Free-positioning and multi-user supportive wireless power transfer systems represent the next-generation technology for wireless charging under the Qi standard. Traditional approaches employ multiple transmitting coils and multi-channel driving circuits with active control algorithms to achieve these goals. However, these traditional approaches are significantly limited by cost, weight, and heating due to their relatively low efficiency. Here, we demonstrate an innovative approach by using a metasurface to achieve free-positioning and multi-user compatibility. The metasurface works as a passive device to reform the magnetic field and enables high-efficiency free-positioning wireless power transfer with only a single transmitting coil. It shows up to 4.6 times improvement in efficiency. The metasurface also increases the coverage area from around 5 cm by 5 cm with over 40% efficiency to around 10 cm by 10 cm with over 70% efficiency. We further show that the system can support multiple receivers. Besides increasing the overall efficiency, we demonstrate tuning the power division between the multiple receivers, enabling compensation of receivers of different sizes to achieve their desired power

    A Stochastic Online Forecast-and-Optimize Framework for Real-Time Energy Dispatch in Virtual Power Plants under Uncertainty

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    Aggregating distributed energy resources in power systems significantly increases uncertainties, in particular caused by the fluctuation of renewable energy generation. This issue has driven the necessity of widely exploiting advanced predictive control techniques under uncertainty to ensure long-term economics and decarbonization. In this paper, we propose a real-time uncertainty-aware energy dispatch framework, which is composed of two key elements: (i) A hybrid forecast-and-optimize sequential task, integrating deep learning-based forecasting and stochastic optimization, where these two stages are connected by the uncertainty estimation at multiple temporal resolutions; (ii) An efficient online data augmentation scheme, jointly involving model pre-training and online fine-tuning stages. In this way, the proposed framework is capable to rapidly adapt to the real-time data distribution, as well as to target on uncertainties caused by data drift, model discrepancy and environment perturbations in the control process, and finally to realize an optimal and robust dispatch solution. The proposed framework won the championship in CityLearn Challenge 2022, which provided an influential opportunity to investigate the potential of AI application in the energy domain. In addition, comprehensive experiments are conducted to interpret its effectiveness in the real-life scenario of smart building energy management.Comment: Preprint. Accepted by CIKM 2

    Selective quantum Zeno effect of ultracold atom-molecule scattering in dynamic magnetic fields

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    We demonstrated that final states of ultracold scattering between atom and molecule can be selectively produced using dynamic magnetic fields of multiple frequencies. The mechanism of the dynamic magnetic field control is based on a generalized quantum Zeno effect for the selected scattering channels. In particular, we use an atom-molecule spin flip scattering to show that the transition to the selected final spin projection of the molecule in the inelastic scattering can be suppressed by dynamic modulation of coupling between the Floquet engineered initial and final states

    Characterization of the Transcriptome of Hair Cell Regeneration in the Neonatal Mouse Utricle

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    Background/Aims: Hearing and balance deficits are mainly caused by loss of sensory inner ear hair cells. The key signals that control hair cell regeneration are of great interest. However, the molecular events by which the cellular signals mediate hair cell regeneration in the mouse utricle are largely unknown. Methods: In the present study, we investigated gene expression changes and related molecular pathways using RNA-seq and qRT-PCR in the newborn mouse utricle in response to neomycin-induced damage. Results: There were 302 and 624 genes that were found to be up-regulated and down-regulated in neomycin-treated samples. GO and KEGG pathway analyses of these genes revealed many deregulated cellular components, molecular functions, biological processes and signaling pathways that may be related to hair cell development. More importantly, the differentially expressed genes included 9 transcription factors from the zf-C2H2 family, and eight of them were consistently down-regulated during hair cell damage and subsequent regeneration. Conclusion: Our results provide a valuable source for future studies and highlighted some promising genes, pathways or processes that may be useful for therapeutic applications

    Багатомовність в Україні та її специфіка

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    У статті висвітлюються аспекти явища багатомовності, характерні для України як для національної держави, котра продовжує перебувати на стадії трансформації державно-політичної, соціально-економічної, духовної систем. Підкреслюється актуальність «аксіоми національної державності», згідно з якою українська мова, яка є рідною для більшості членів титульної нації країни, має бути єдиною державною мовою.The article studies the aspects of the phenomenon of multilingualism which are characteristic of Ukraine as a national state that remains at the stage of final forming complicated by the transformation of state political, social, economic and spiritual systems. The author underlines actuality of “the axiom of national statehood” that expects Ukrainian to be official language because it is native for the most of members of a titular nation in Ukraine

    A 4.8-kW high-efficiency 1050-nm monolithic fiber laser amplifier employing a pump-sharing structure

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    The power scaling of ytterbium-doped fiber (YDF) lasers emitting at the wavelength range of 1030 nm–1060 nm has been limited by amplified spontaneous emission (ASE), stimulated Raman scattering (SRS) effect, and transverse mode instability (TMI). These effects pose challenges in achieving a high-output power laser within the range of 1030 nm–1060 nm while maintaining a high signal-to-noise ratio. Based on a counter-pumped fiber laser amplifier utilizing our self-developed ytterbium-doped fiber, we have successfully showcased a 4.8-kW laser output at 1050 nm, accompanied by an 85.3% slope efficiency and nearly diffraction-limited beam quality. By effectively applying ASE and TMI, and controlling the Raman Stokes at ∼17 dB below the primary signal wavelength, we have achieved optimal performance at the maximum power level. This high efficiency has been attained through a pump-sharing structure combined with cost-effective, non-wavelength-stabilized 976-nm laser diodes

    Induction of hepatic enzymes and oxidative stress in Chinese rare minnow (Gobiocypris rarus) exposed to waterborne hexabromocyclododecane (HBCDD)

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    The objective of this study was to evaluate the sub-lethal toxicity of hexabromocyclododecane (HBCDD) in fish. Adult Chinese rare minnows as in vivo models were exposed to waterborne HBCDD from 1 to 500 mu g/l for 14, 28 and 42 days. Hepatic CYP1A1 (ethoxyresorufin-O-deethylase, EROD) and CYP2B1 (pentaoxyresorufin-O-depentylase, PROD) activities were measured. At the same time, molecular biomarkers of oxidative stress were also assayed in the brain, including reactive oxygen species (ROS), lipid peroxidation products (thiobarbituric acid-reactive substances, TBARS), DNA damage and protein carbonyl, as well as superoxide dismutase (SOD) activity and glutathione (GSH) content. DNA damage was evaluated using the Comet assay on erythrocytes. Besides, the content of HBCDD in whole fish was determined after 42 days exposure. The results show that HBCDD could induce EROD and PROD at 500 mu g/l after 28 days exposure, and at 100 to 500 mu g/l after 42 days exposure (P < 0.05), respectively. ROS formation in fish brain was observed to be increased in both time- and dose-dependent manner due to HBCDD exposure. The significant increases in TBARS and protein carbonyl contents occurred in fish brain after 28 and 42 days exposure (P < 0.05). Significant DNA damage in erythrocytes by Comet assay was also found in the 100-500 mu g/l exposure groups (P < 0.05) after 42 days exposure. Moreover, significant depletion in brain GSH content occurred in all treated groups (P < 0.05) and apparent inhibition in SOD activity in brain was observed in the groups of 10-500 mu g/l concentrations during 42 days exposure. The results demonstrate that increasing duration of HBCDD exposure induced EROD and PROD activities, caused excess ROS formation, finally resulted in oxidative damage to lipids, proteins and DNA and decreased antioxidant capacities in fish. Chemical analysis of HBCDD in whole fish showed accumulation up to 654 mu g/g wet weight. (c) 2007 Elsevier B.V. All rights reserved.The objective of this study was to evaluate the sub-lethal toxicity of hexabromocyclododecane (HBCDD) in fish. Adult Chinese rare minnows as in vivo models were exposed to waterborne HBCDD from 1 to 500 mu g/l for 14, 28 and 42 days. Hepatic CYP1A1 (ethoxyresorufin-O-deethylase, EROD) and CYP2B1 (pentaoxyresorufin-O-depentylase, PROD) activities were measured. At the same time, molecular biomarkers of oxidative stress were also assayed in the brain, including reactive oxygen species (ROS), lipid peroxidation products (thiobarbituric acid-reactive substances, TBARS), DNA damage and protein carbonyl, as well as superoxide dismutase (SOD) activity and glutathione (GSH) content. DNA damage was evaluated using the Comet assay on erythrocytes. Besides, the content of HBCDD in whole fish was determined after 42 days exposure. The results show that HBCDD could induce EROD and PROD at 500 mu g/l after 28 days exposure, and at 100 to 500 mu g/l after 42 days exposure (P < 0.05), respectively. ROS formation in fish brain was observed to be increased in both time- and dose-dependent manner due to HBCDD exposure. The significant increases in TBARS and protein carbonyl contents occurred in fish brain after 28 and 42 days exposure (P < 0.05). Significant DNA damage in erythrocytes by Comet assay was also found in the 100-500 mu g/l exposure groups (P < 0.05) after 42 days exposure. Moreover, significant depletion in brain GSH content occurred in all treated groups (P < 0.05) and apparent inhibition in SOD activity in brain was observed in the groups of 10-500 mu g/l concentrations during 42 days exposure. The results demonstrate that increasing duration of HBCDD exposure induced EROD and PROD activities, caused excess ROS formation, finally resulted in oxidative damage to lipids, proteins and DNA and decreased antioxidant capacities in fish. Chemical analysis of HBCDD in whole fish showed accumulation up to 654 mu g/g wet weight. (c) 2007 Elsevier B.V. All rights reserved

    Matrine Reverses the Warburg Effect and Suppresses Colon Cancer Cell Growth via Negatively Regulating HIF-1α.

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    The Warburg effect is a peculiar feature of cancer’s metabolism, which is an attractive therapeutic target that could aim tumor cells while sparing normal tissue. Matrine is an alkaloid extracted from the herb root of a traditional Chinese medicine, Sophora flavescens Ait. Matrine has been reported to have selective cytotoxicity toward cancer cells but with elusive mechanisms. Here, we reported that matrine was able to reverse the Warburg effect (inhibiting glucose uptake and lactate production) and suppress the growth of human colon cancer cells in vitro and in vivo . Mechanistically, we revealed that matrine significantly decreased the messenger RNA (mRNA) and protein expression of HIF-1α, a critical transcription factor in reprogramming cancer metabolism toward the Warburg effect. As a result, the expression levels of GLUT1, HK2, and LDHA, the downstream targets of HIF-1α in regulating glucose metabolism, were dramatically inhibited by matrine. Moreover, this inhibitory effect of matrine was significantly attenuated when HIF-1α was knocked down or exogenous overexpressed in colon cancer cells. Together, our results revealed that matrine inhibits colon cancer cell growth via suppression of HIF-1α expression and its downstream regulation of Warburg effect. Matrine could be further developed as an antitumor agent targeting the HIF-1α-mediated Warburg effect for colon cancer treatment
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