The relation of cytokines of IL-17/IL-23 axis to Th1/Th2 cytokines and disease activity in systemic lupus erythematosus

INTRODUCTION: Interleukin (IL)-17 is recently linked to the pathogenesis of systemic lupus erythematosus (SLE) but its relation to disease activity has not been well characterised. The objectives of this study were to examine the relation of serum cytokine levels from the IL-17/IL-23 axis (IL-17, IL-23) to Th1 (IL-12, IFN-γ), Th2 (IL-10, IL-6, IL-4) cytokines and disease activity in SLE patients. METHODS: Serum cytokines were measured by enzyme-linked immunosorbent assays. Disease activity was determined by SLE disease activity index (SLEDAI), anti-dsDNA antibody, C3 and C4 levels. RESULTS: Serum levels of IL-17, IL-10 and IFN-γ were higher in SLE patients (n=70) compared to age- and sexmatched controls (n=14) [P<0.001]. Higher serum IL-23 level was found in active lupus patients who had cutaneous manifestation (P=0.003) and serositis (P=0.03) compared to those who had not. Serum IL-17 was not different between patients who had active lupus nephritis (n=23), non-renal active lupus (n=13) and inactive disease (n=34) [P=0.23]. However, an inverse correlation between serum IL-17 with proteinuria was found among all SLE patients (r= –0.27, P=0.03). Serum IL-17 level was, otherwise, not related to SLEDAI, glomerular filtration rate, activity or chronicity score and ISN/RPS class among patients with active lupus nephritis and was not found to correlate with serum IFN-γ or IL-10. CONCLUSIONS: Elevated serum IL-23 was found in patients with inflammatory manifestations including cutaneous involvement and serositis. Serum IL-17 level was not shown to correlate with disease activity but demonstrated an inverse correlation with proteinuria suggesting urinary loss of IL-17 and its involvement in lupus renal pathology.published_or_final_versionThe 15th Medical Research Conference (15th MRC), Department of Medicine, University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16 n. 1, suppl. 1, p. 45, abstract no. 7

Design of fuzzy damping controller of UPFC through genetic algorithm

The addition of a PSS-like supplementary controller to the UPFC main control can provide effective damping to the low frequency oscillation on the heavily loaded tie lines of interconnected power system. However, the conventional controller designed based on a linearized model cannot provide satisfactory performance over a wide range of operation point and under large disturbances. In this paper, the design of the Fuzzy Damping Controller (FDC) for UPFC as a substitute of the conventional supplementary controller is presented. Scaling factors are inserted to the membership functions of both inputs and output for easy design of fuzzifier and defuzzifier. Genetic Algorithm (GA) is applied to optimize the performance of the FDC through fine-tuning of the scaling factors. A 4-machine interconnected power system is used as the test system with a UPFC installed in one of the tie lines. Comparisons between the performances of both the fuzzy and the conventional supplementary controllers are studied. Computer test results show that FDC is very effective in damping the oscillation and in the meantime has a better robustness as compared with its conventional counterpart.published_or_final_versio

A study of fuzzy logic based damping controller for the UPFC

The supplementary control of the UPFC can significantly enhance the damping of interconnect power systems. However, the conventional controller designed based on a linearized model cannot provide adequate damping signal over a wide range of operation points. In this paper, a fuzzy controller is designed as the substitute of the conventional controller. The parameters of the fuzzy controller are optimized through gradient descent training. Transient stability simulation and small signal analysis are conducted to test the performance of the controller. Computer results show that the fuzzy controller is very effective in damping the oscillation and has a better robustness.published_or_final_versio

Decentralization and marketization of education in China: challenges for migrant children and social harmony

Parallel Session II Governing the Asian Giants - Good Governance and Public Policy: Session on Managing Urban Development and Policy ResponsespostprintLaunch Conference for Journal of Asian Public Policy: "Governing the Asian Giants: The Search for Good Governance and Sustainable Development in China and India", Hong Kong, China, 29-30 March 2010

Southern Chinese patients with systemic lupus erythematosus in Hong Kong have low vitamin D levels

BACKGROUND: Vitamin D insufficiency has been linked to pathogenesis of autoimmune diseases. This study aimed to measure serum 25(OH)D level in patients with systemic lupus erythematosus (SLE) in Hong Kong and to evaluate association between serum 25(OH)D level and disease activity. METHODS: Serum 25(OH)D level was measured by radioimmunoassay in SLE patients and healthy controls. Lupus disease activity was determined by SLE disease activity index (SLEDAI), serum anti-dsDNA antibody, C3 and C4 levels. RESULTS: Fifty-two SLE patients with mean ± standard deviation disease duration of 15.5±8.6 years were recruited. Five patients had active lupus disease. Five (9.6%) patients had serum 25(OH)D levels <30 nmol/L. Serum 25(OH)D level was significantly lower in SLE patients compared to age- and sex-matched controls (n=52) [45.5±12.3 vs 51.1±12.6 nmol/L, P=0.02]. Serum 25(OH)D levels were not found to be related to SLEDAI, elevated anti-dsDNA antibody, low C3 or C4 levels or medications. One vitamin D insufficient patient had low serum albumin-corrected calcium. Serum 25(OH)D levels were found to correlate negatively with estimated glomerular filtration rate (r= –0.30, P=0.03) but was not different between patients who had normal and impaired renal function (P=0.38). CONCLUSION: SLE patients in Hong Kong were found to have low serum 25(OH)D level despite its subtropical location.published_or_final_versionThe 15th Medical Research Conference (15th MRC), Department of Medicine, University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16 n. 1, suppl. 1, p. 47, abstract no. 7

Nonlinear Dynamic Power Tracking of Low-Power Wind Energy Conversion System

This paper addresses the use of variable structure control (i.e., sliding mode (SM) control) for improving the dynamic performance of a low-power wind energy conversion system (WECS) that is connected to a dc grid. The SM control is applied to simultaneously match 1) the maximum power generation of the wind turbine system from the wind with 2) the maximum power injection of the grid-connected power converter into the grid. The amount of energy extractable from a dynamically changing wind using the WECS with SM control is compared with that of classic PI control. Both the simulation and experimental results show that more energy can be harvested with the SM control as compared to the PI control for any dynamically changing or random wind conditions

Gait Difficulty, Postural Instability, and Muscle Weakness Are Associated with Fear of Falling in People with Parkinson's Disease

The present study aimed to examine the contribution of gait impairment, postural stability and muscle weakness to the level of fear of falling in people with Parkinson's disease (PD). Fifty-seven community-dwelling individuals with PD completed the study. Fear of falling was assessed by the Activities-specific Balance Confidence (ABC) scale. Postural stability and gait difficulty were determined by the posture and gait subscores of the Unified Parkinson's Disease Rating Scale (UPDRS-PG). A Cybex dynamometer was used to measure isokinetic knee muscle strength. Individuals with PD achieved a mean ABC score of 73.6 ± 19.3. In the multiple regression analysis, after accounting for basic demographics, fall history and disease severity, the UPDRS-PG score remained independently associated with the ABC score, accounting for 13.4% of the variance (P < 0.001). The addition of knee muscle strength significantly improved the prediction model and accounted for an additional 7.3% of the variance in the ABC score (P < 0.05). This is the first study to demonstrate that the UPDRS-PG score and knee muscle strength are important and independent determinants of the level of fear of falling in individuals with PD. Improving balance, gait stability and knee muscle strength could be crucial in promoting balance confidence in the appropriately targeted PD population

Low-power wind energy conversion system with variable structure control for DC grids

This paper presents a discussion on the use of variable structure control, i.e., sliding mode control, for improving the dynamic control performance of a low-power wind energy conversion system (WECS) that is connected to a DC microgrid. The sliding mode control is applied to the wind turbine system to extract the maximum possible power from the wind, thus achieving the state of maximum power point tracking to reach the maximum power generation (MPG), and also applied to the power converter to reach the maximum power injection (MPI) to the load. The amount of energy extractable from a dynamically changing wind using the WECS with sliding mode control is compared with that of the classic PI controller. Simulation results show that for a dynamically changing wind, more energy can be harvested with the sliding mode control as compared to the PI control. © 2014 IEEE.published_or_final_versio