226 research outputs found
Convergence analysis of distributed fixed-step power control algorithm for cellular mobile systems
[[abstract]]Power control plays a vital role in the operation of cellular systems. It has been shown that a power control mechanism with distributed fixed-step control algorithm using a single bit can maintain the received carrier-to-interference ratio (CIR) within a desired range in long-term fading channels. However, as far as the short-term fading is concerned, whether such a power control algorithm remains convergent is not clear. In this work, a simple received CIR model is adopted to derive the condition that ensures system stability for short-term fading channels. The bounds of the received CIR are also obtained. Furthermore, the effects of the power control step size and the time required for convergence are also analyzed. Copyright (C) 2007 John Wiley & Sons, Ltd
Improved Quantum-Inspired Evolutionary Algorithm for Engineering Design Optimization
An improved quantum-inspired evolutionary algorithm is proposed for solving mixed discrete-continuous nonlinear problems in engineering design. The proposed Latin square quantum-inspired evolutionary algorithm (LSQEA) combines Latin squares and quantum-inspired genetic algorithm (QGA). The novel contribution of the proposed LSQEA is the use of a QGA to explore the optimal feasible region in macrospace and the use of a systematic reasoning mechanism of the Latin square to exploit the better solution in microspace. By combining the advantages of exploration and exploitation, the LSQEA provides higher computational efficiency and robustness compared to QGA and real-coded GA when solving global numerical optimization problems with continuous variables. Additionally, the proposed LSQEA approach effectively solves mixed discrete-continuous nonlinear design optimization problems in which the design variables are integers, discrete values, and continuous values. The computational experiments show that the proposed LSQEA approach obtains better results compared to existing methods reported in the literature
Performance evaluation of random power capture on mobile communicationsR
SUMMARY Power assignment schemes are man-made methods to enhance the capture e!ect of radio communications. In a previous study, Wen and Yang investigated the combined capture e!ect of the "xed power assignment scheme, Rayleigh fading, and near}far e!ect on the performance of packet radios. The performance analysis was limited to an in"nite population environment. This assumption is reasonable for a conventional packet radio system with a vast service area. However, for a cellular mobile system, a "nite population model should be used. In this paper, we analyse the combined natural and man-made capture e!ect on the performance of a cellular system with "nite population in each cell. A random power assignment scheme is adopted to produce the man-made capture. The system throughput and delay are carried out by a Markov model. Some numerical calculations are used to demonstrate the degree of performance improvement
Whole-body vibration training effect on physical performance and obesity in mice
The purpose of this study was to verify the beneficial effects of whole-body vibration (WBV) training on exercise performance, physical fatigue and obesity in mice with obesity induced by a high-fat diet (HFD). Male C57BL/6 mice were randomly divided into two groups: normal group (n=6), fed standard diet (control), and experimental group (n=18), fed a HFD. After 4-week induction, followed by 6-week WBV of 5 days per week, the 18 obese mice were divided into 3 groups (n=6 per group): HFD with sedentary control (HFD), HFD with WBV at relatively low-intensity (5.6 Hz, 0.13 g) (HFD+VL) or high-intensity (13 Hz, 0.68 g) (HFD+VH). A trend analysis revealed that WBV increased the grip strength in mice. WBV also dose-dependently decreased serum lactate, ammonia and CK levels and increased glucose level after the swimming test. WBV slightly decreased final body weight and dose-dependently decreased weights of epididymal, retroperitoneal and perirenal fat pads and fasting serum levels of alanine aminotransferase, CK, glucose, total cholesterol and triacylglycerol. Therefore, WBV could improve exercise performance and fatigue and prevent fat accumulation and obesity-associated biochemical alterations in obese mice. It may be an effective intervention for health promotion and prevention of HFD-induced obesity
Bioactive Eunicellin-Based Diterpenoids from the Soft Coral Cladiella krempfi
Four new eunicellin-based diterpenoids, krempfielins A–D (1–4), along with two known compounds (5 and 6) have been isolated from a soft coral Cladiella krempfi. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and by comparison with spectroscopic data of related known compounds. Compounds 5 and 6 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. Furthermore, compounds 2, 3, 5 and 6 were shown to exert significant in vitro anti-inflammatory activity against LPS-stimulated RAW264.7 macrophage cells
Effects of Angelica dahurica
The main objective of wound treatments is to restore the functional skin properties and prevent infection. Traditional Chinese medicine provides alternative anti-inflammatory, antimicrobial, and wound healing therapies. Both Angelica dahurica extract (AE) and Rheum officinale extract (RE) possess antimicrobial activity. In this study, AE and RE were applied in wound treatment to investigate their healing effects. Thirty Sprague-Dawley rats with dorsal full-thickness skin excision were divided into normal saline (NS), AE, RE, AE plus RE (ARE), and Biomycin (BM) groups. The treatment and area measurement of wounds were applied daily for 21 days. Wound biopsies and blood samples were obtained for histology examinations and cytokine analysis. Results showed that wound contraction in ARE group was significantly higher than that in NS and BM groups (P 0.05), and plasma TGF-β1 levels were significantly lower than those in the NS group on days 3-4 (P < 0.05). In conclusion, ARE accelerates wound healing during inflammation and proliferation phases
Topical application of marine briarane-type diterpenes effectively inhibits 12-O-tetradecanoylphorbol-13-acetate-induced inflammation and dermatitis in murine skin
<p>Abstract</p> <p>Background</p> <p>Skin is the largest organ in the body, and is directly exposed to extrinsic assaults. As such, the skin plays a central role in host defense and the cutaneous immune system is able to elicit specific local inflammatory and systemic immune responses against harmful stimuli. 12-O-tetradecanoylphorbol-13-acetate (TPA) can stimulate acute and chronic inflammation and tumor promotion in skin. TPA-induced dermatitis is thus a useful <it>in vivo </it>pharmacological platform for drug discovery. In this study, the inhibitory effect of briarane-type diterpenes (BrDs) from marine coral <it>Briareum excavatum </it>on TPA-induced dermatitis and dendritic cell (DC) function was explored.</p> <p>Methods</p> <p>Evans blue dye exudation was used to determine vascular permeability. H&E-stained skin section was used to determine the formation of edema in mouse abdominal skin. We also used immunohistochemistry staining and western blot assays to evaluate the activation of specific inflammation makers and key mediators of signaling pathway in the mouse skin. Furthermore, mouse bone marrow DCs were used to determine the relationship between the chemical structure of BrDs and their regulation of DC function.</p> <p>Results</p> <p>BrD1 remarkably suppressed TPA-induced vascular permeability and edema in skin. At the biochemical level, BrD1 inhibited TPA-induced expression of cyclooxygenase-2, inducible nitric oxide synthase and matrix metalloproteinase-9, the key indicators of cutaneous inflammation. This inhibition was apparently mediated by interference with the Akt/NF-κB-mediated signaling network. BrD1 also inhibited TNF-α and IL-6 expression in LPS-stimulated BMDCs. The 8, 17-epoxide of BrDs played a crucial role in the inhibition of IL-6 expression, and replacement of the C-12 hydroxyl group with longer esters in BrDs gradually decreased this inhibitory activity.</p> <p>Conclusions</p> <p>Our results suggest that BrDs warrant further investigation as natural immunomodulatory agents for control of inflammatory skin diseases.</p
Assessing the Long-Term Creep Behaviour of Hydrothermally Treated Japanese Cedar Wood Using the Short-Term Accelerated Stepped Isostress Method
In this study, short-term accelerated creep tests were conducted using the stepped isostress method (SSM) to investigate the impact of hydrothermal treatment on the long-term creep behaviour of Japanese cedar wood and to determine optimal hydrothermal treatment conditions. The results showed that SSM can effectively predict the creep behaviour of hydrothermally treated wood. Among the treatment conditions tested, Japanese cedar wood treated hydrothermally at 180 ◦C for 4 h exhibited higher flexural strength retention (91%) and moisture excluding efficiency (MEE) (44%) and demonstrated superior creep resistance compared to untreated wood. When subjected to a 30% average breaking load (ABL) over 20 years, the specimen’s creep compliance, instantaneous creep compliance, b value, activation volume, and improvement in creep resistance (ICR) were 0.17 GPa−1, 0.139 GPa−1, 0.15, 1.619 nm3, and 4%, respectively. The results indicate that subjecting Japanese cedar wood to hydrothermal treatment at 180 ◦C for 4 h has a negligible effect on its flexural properties but results in significant improvements in both dimensional stability and creep resistance
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