6,901 research outputs found
A Simple Decentralized Charging Control Scheme of Plug-in Electric Vehicles for Alleviating Wind Farm Intermittency
AbstractVariable power output from large-scale wind farms present new challenge of balancing power system load with generation. To alleviate this problem, this paper proposes a decentralized charging control scheme for plug-in electric vehicles (PEVs) to neutralize wind power fluctuations. In the proposed scheme, each PEV autonomously adjusts its power in response to a real-time directing signal and based on its own urgency level of charging. No intelligent central control entity is needed. Simulation results demonstrate the effectiveness of the proposed charging control in directing PEV power to counteract wind power fluctuations. Also, proportionally fair distribution of counteracting duties among PEVs can be achieved so as to meet heterogeneous charging requirements of PEV users, and the total utility of the PEV fleet is proven to be maximized
A Framework for Self-healing Smart Grid with Incorporation of Multi-Agents
AbstractA hierarchical framework incorporated with multi-agents is proposed for enabling the self-healing of smart grid. While the central control agent in the upper layer adopts the multiple-step Taylor series function (MTSF) method to efficiently predict the system stability using wide area measurement system (WAMS) data, agents with shared information in the lower layer protect the devices in plug-in micro grids more effectively and adaptively compared with traditional protection. The proposed framework shows the self-healing capability for ensuring the security of smart grid by reliably preventing faults and flexibly coordinating generations. Simulation results of modified WSCC 3-generator system with plug-in micro grids have confirmed the validity of the proposed framework
Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility
Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials
Design and characterisation of a new duplex surface system based on S-phase hardening and carbon-based coating for ASTM F1537 CoâCrâMo alloy
AbstractCoâCrâMo alloys are one of the most widely used metallic biomaterials for metal-on-metal joint prostheses. However, concerns over increased revision rates mainly due to nano-sized wear debris have been raised. This study was aimed at enhancing the friction, wear and load-bearing properties of CoâCrâMo alloys by developing a new duplex surface system combining super hard and wear-resistant S-phase layer with self-lubricating, low-friction carbon-based coating. To this end, ASTM F1537 CoâCrâMo alloy surface was plasma carburised (PC) at 450°C and then coated with a carbon-based GiC coating. The microstructures of the duplex and single treated (PC or GiC coating) CoâCrâMo surface systems were characterized and their mechanical, tribological and corrosion properties were evaluated. The results showed that the new duplex surface system exhibited a high load bearing capacity, a low friction coefficient, excellent wear resistance and good corrosion behaviour
Pseudo almost automorphic behavior of solutions to a semi-linear fractional differential equation
In this paper, we shall deal with -pseudo almost automorphic solutions to a semi-linear fractional differential equation by new concept of -pseudo almost automorphic functions presented recently. We first establish some new properties of -pseudo almost automorphic functions, and then we apply the results obtained to prove some existence theorems combined with the Leray-Schauder alternative theorem
Correlational Analysis of Sarcopenia and Multimorbidity Among Older Inpatients
BACKGROUND: Sarcopenia and multimorbidity are common in older adults, and most of the available clinical studies have focused on the relationship between specialist disorders and sarcopenia, whereas fewer studies have been conducted on the relationship between sarcopenia and multimorbidity. We therefore wished to explore the relationship between the two.
METHODS: The study subjects were older patients (agedââ„â65 years) who were hospitalized at the Department of Geriatrics of the First Affiliated Hospital of Chongqing Medical University between March 2016 and September 2021. Their medical records were collected. Based on the diagnostic criteria of the Asian Sarcopenia Working Group in 2019, the relationship between sarcopenia and multimorbidity was elucidated.
RESULTS: 1.A total of 651 older patients aged 65 years and above with 2 or more chronic diseases were investigated in this study, 46.4% were suffering from sarcopenia. 2. Analysis of the relationship between the number of chronic diseases and sarcopenia yielded that the risk of sarcopenia with 4-5 chronic diseases was 1.80 times higher than the risk of 2-3 chronic diseases (OR 1.80, 95%CI 0.29-2.50), and the risk of sarcopenia with â„â6 chronic diseases was 5.11 times higher than the risk of 2-3 chronic diseases (OR 5.11, 95% CI 2.97-9.08), which remained statistically significant, after adjusting for relevant factors. 3. The Charlson comorbidity index was associated with skeletal muscle mass index, handgrip strength, and 6-meter walking speed, with scores reaching 5 and above suggesting the possibility of sarcopenia. 4. After adjusting for some covariates among 14 common chronic diseases in older adults, diabetes (OR 3.20, 95% CI 2.01-5.09), cerebrovascular diseases (OR 2.07, 95% CI 1.33-3.22), bone and joint diseases (OR 2.04, 95% CI 1.32-3.14), and malignant tumors (OR 2.65, 95% CI 1.17-6.55) were among those that still a risk factor for the development of sarcopenia.
CONCLUSION: In the hospitalized older adults, the more chronic diseases they have, the higher the prevalence of sarcopenia. When the CCI is 5, attention needs to be paid to the occurrence of sarcopenia in hospitalized older adults
Inhibition of proliferation, migration and invasion of human non-small cell lung cancer cell line A549 by phlomisoside F from Phlomis younghusbandii Mukerjee
Purpose: To determine the effect of phlomisoside F (PMF) on the proliferation, migration and invasion of human non-small cell lung cancer cell line A549 and explore the possible mechanisms.Methods: The anti-proliferative effect of PMF on A549 cells was determined by CCK-8. Subsequently, migration and invasion were evaluated by Transwell and Transwell with matrigel assays, respectively. Furthermore, cell cycle and apoptosis were assessed by flow cytometry, while the mechanisms of action were determined by Western blotting.Results: PMF exhibited significant anti-proliferative effect on A549 cells in concentration-dependent and time-dependent manners, with half maximal inhibitory concentration (IC50) of 54.51 ΌM. Treatment with PMF (10, 20 and 40 ΌM) for 48 h resulted in significantly decreased migration and invasion in A549 cells. In addition, PMF at concentrations of 25, 50 and 75 ΌM induced cell cycle arrest in G0/G1phase and enhanced cell apoptosis in A549 cells. Furthermore, caspase-3, caspase-9 and Bax protein expressions were up-regulated while Bacl-2 and COX-2 protein expressions were significantly downregulated at 10, 20 and 40 ΌM concentrations of PMF.Conclusion: PMF suppresses A549 cell growth, migration and invasion. The mechanism may be related to the induction of mitochondria-mediated apoptosis pathway via regulation of caspase-3, caspase-9, Bcl-2 and Bax expressions, and inhibition of PGE2 synthesis by reducing COX-2 expression.Keywords: Phlomisoside F, Lung cancer, Cell mobility, Apoptosis, PGE2, COX-2 expression, Caspase, Cell cycle arres
Interionic Energy Transfer in Y\u3csub\u3e3\u3c/sub\u3eAl\u3csub\u3e5\u3c/sub\u3eO\u3csub\u3e12\u3c/sub\u3e: Ce\u3csup\u3e3+\u3c/sup\u3e, Pr\u3csup\u3e3+\u3c/sup\u3e Phosphor
We present an investigation of dynamical processes of nonradiative energy transfer (ET)between Ce3+ and Pr3+ , and between Pr3+ ions in Y3Al5O12:Ce3+ , Pr3+ phosphor.Photoluminescence spectroscopy and fluorescence decay patterns are studied as a function ofPr3+ and Ce3+ concentrations. The analysis based on InokutiâHirayama model indicates that the ET from the lowest 5d state of Ce3+ to the D12 state of Pr3+ , and the quenching of theD12 state through a cross relaxation involving Pr3+ ions in the ground state are both governed by electric dipoleâdipole interaction. An increase in the Ce3+âPr3+ ET rate followed by the enhanced red emission line of Pr3+ relative to the yellow emission band of Ce3+ on only increasing Ce3+ concentration is observed. This behavior is attributed to the increase in thespectral overlap integrals between Ce3+ emission and Pr3+ excitation due to the fact that the yellow band shifts to the red spectral side with increasing Ce3+ concentration while the red line dose not move. For Ce3+ concentration of 0.01 in YAG:Ce3+ , Pr3+ , the rate constant and critical distance are evaluated to be 4.5Ă10â36âcm6âsâ1 , 0.81 nm for Ce3+âPr3+ ET and2.4Ă10â38âcm6âsâ1 , 1.30 nm for Pr3+âPr3+ ET. Spectroscopic study also demonstrates a pronounced ET from the lowest 4f5d of Pr3+ to the 5d of Ce3+ . A proportional dependence of the initial transfer rate on acceptor concentration is observed in each of these ET pathways. The proportional coefficient as the averaged ET parameters for initial decay are determined, meaning the ET efficiency for the same concentration of acceptors follows the order ofPr3+âPr3+\u3ePr3+âCe3+\u3eCe3+âPr3+
Color Control and White Light Generation of Upconversion Luminescence by Operating Dopant Concentrations and Pump Densities in Yb\u3csup\u3e3+\u3c/sup\u3e, Er\u3csup\u3e3+\u3c/sup\u3e, and Tm\u3csup\u3e3+\u3c/sup\u3e Tri-Doped Lu\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e Nanocrystals
We synthesized a series of Yb3+, Er3+ and Tm3+ tri-doped Lu2O3 nanocrystals with various dopant concentrations by the hydrothermal approach. Due to a unique electronic state at the top of the valence band, Lu2O3 based materials exhibit intense upconversion luminescence involving 1G4 â 3H6 of Tm3+ in blue, (2H11/2, 4S3/2) â 4I15/2 in green and 4F9/2 â 4I15/2 in red of Er3+ upon near infrared excitation at 980 nm. The variation of upconversion spectra and color points with dopant concentrations and pump densities are studied in detail on the basis of energy transfer processes. An ideal white upconversion light with color coordinates of (0.327, 0.339) is obtained by controlling the intensity of red, green, and blue emission in Lu1.906Yb0.08Er0.008Tm0.006O3nanocrystals under a pump density of 8 W cmâ2. Based on the present experimental data, we may predict the dopant concentrations and pump densities for any color point within or around the white light region in the tri-doped Lu2O3 nanocrystals
The HI gas fraction scaling relation of the Green Pea galaxies
Green Pea galaxies are compact galaxies with high star formation rates.
However, limited samples of Green Pea galaxies have HI 21 cm measurements.
Whether the HI gas fraction f_{HI} = M_{HI}/M_{*} of Green Pea galaxies follows
the existing scaling relations between the f_{HI} and NUV-r color or linear
combinations of color and other physical quantities needs checking. Using
archival data of HI 21cm observations, we investigate the scaling relation of
the NUV-r color with the M_{HI}/M_{*} of 38 Green Pea galaxies, including 17
detections and 21 non-detections. The HI to stellar mass ratios (f_{HI}) of
Green Pea galaxies deviate from the polynomial form, where a higher HI gas
fraction is predicted given the current NUV-r color, even with the emission
lines removed. The blue sources (NUV-r<1) from the comparison sample
(ALFALFA-SDSS) follow a similar trend. The HI gas fraction scaling relations
with linear combination forms of -0.34(NUV-r) - 0.64 log(mu_{*,z}) + 5.94 and
-0.77 log mu_{*,i} + 0.26 log SFR/M_{*}+8.53, better predict the HI gas
fraction of the Green Pea galaxies. In order to obtain accurate linear combined
forms, higher-resolution photometry from space-based telescopes is needed.Comment: 15 pages, 7 figures, to be published in RA
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