654 research outputs found

    Adaptive group consensus of coupled harmonic oscillators with multiple leaders

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    In this paper, we investigate the group consensus of coupled harmonic oscillators with multiple leaders in an undirected fixed network. Unlike many existing algorithms for group consensus of multi-agent systems or cluster synchronization of complex dynamical networks, which require global information of the underlying network such as the eigenvalues of the coupling matrix or centralized control protocols, we propose a novel decentralized adaptive group consensus algorithm for coupled harmonic oscillators. By using the decentralized adaptive group consensus algorithm and without using any global information of the underlying network, all agents in the same group asymptotically synchronize with the corresponding leader even when only one agent in each group has access to the information of the corresponding leader. Numerical simulation results are presented to illustrate the theoretical results. Β© 2012 IEEE.published_or_final_versio

    A design for investigating the association of birth weight, weight change during life course with adult hypertension in Hong Kong women

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    Poster Presentation: P-6A-270"Fetal origins hypothesis" by Barker in 1990 is a well known hypothesis. One of the key finding was that low birth weight was associated with higher adult systolic blood pressure. However, in 2002, Huxley et al argued that birth weight had little relevance in determining blood pressure levels in later life. But after that, several studies argued against it until now. In addition, some experts think that change in size between birth and current rather than fetal biology itself affect the blood pressure, which means the fetal origins hypothesis must be weighed against a "postnatal origins hypothesis". Therefore, it is important to explore what is the interaction between later body weight change and fetal programming on the effect of BP ...published_or_final_versio

    Adaptive flocking of multi-agent systems with locally Lipschitz nonlinearity

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    This paper investigates adaptive flocking of multi-agent systems (MASs) with a virtual leader. All agents and the virtual leader share the same intrinsic nonlinear dynamics, which satisfies a locally Lipschitz condition and depends on both position and velocity information of the agent itself. Under the assumption that the initial network is connected, an approach to preserving the connectivity of the network is proposed. Based on the Lyapunov stability theory, an adaptive flocking control law is derived to make the MASs track the virtual leader without collision. Finally, a numerical example is presented to illustrate the effectiveness of the theoretical results. Β© 2012 Chinese Assoc of Automati.published_or_final_versio

    Decentralized adaptive pinning control for cluster synchronization of complex dynamical networks

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    Antifatigue Effect of Millettiae speciosae Champ (Leguminosae) Extract in Mice

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    Purpose: To evaluate whether Millettiae Speciosae Champ. (Leguminosae) can enhance exercise performance as well as ascertain if it a potential functional food material.Methods: The extract of Millettia speciosa Champ. (MSE) was orally administered to mice in 500, 1000, 2000 mg/kg doses to investigate its anti-fatigue effect in both forced swimming and climbing tests. Glycogen, triglyceride (TG), blood urea nitrogen (BUN) and creatine phosphokinase (CK) levels in plasma which can indicate alterations in energy utilization during exercise performance, were determined to analyze the operating exercise mechanisms.Results: The results showed that swimming time to exhaustion was longer in all treated groups (41.06 Β± 1.92, 47.84 Β± 1.60, 54.00 Β± 2.45 min for 500, 10000 and 2000 mg/kg doses, respectively) than for control (19.45 Β± 0.62 min, p < 0.05). The middle and high doses of MSE-treated groups significantly prolonged the climbing time compared with control (p < 0.05). Furthermore, MSE reduced the content of TG significantly by increasing fat utilization, delayed the accumulation of BUN and decreased the level of CK (p < 0.05). In addition, administration of MSE significantly protected the depletion of muscle glycogen when compared with control (p < 0.05).Conclusion: The results show for the first time that Millettia speciosa Champ. (Leguminosae) has significant anti-fatigue activity, and also suggest that it is a potential functional food material.Keywords: Radix millettiae speciosae, Anti-fatigue activity, Exercise performance, Serum urea nitrogen, Gastrocnemius muscle glycogen, Triglyceride, Functional foo

    Correlation between promoter methylation of p14ARF, TMS1/ASC, and DAPK, and p53 mutation with prognosis in cholangiocarcinoma

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    <p>Abstract</p> <p>Background</p> <p>To study the methylation status of genes that play a role in the p53-Bax mitochondrial apoptosis pathway and its clinical significance in cholangiocarcinoma.</p> <p>Patients and Methods</p> <p>Out of 36 cases cholangiocarcinoma patients from April 2000 to May 2005 were collected.Promoter hypermethylation of <it>DAPK</it>, <it>p14<sup>ARF</sup></it>, and <it>ASC </it>were detected by methylation-specific PCR on cholangiocarcinoma and normal adjacent tissues samples. Mutation of the p53 gene was examined by automated sequencing. Correlation between methylation of these genes and/or <it>p53 </it>mutation status with clinical characteristics of patients was investigated by statistical analysis.</p> <p>Results</p> <p>We found 66.7% of 36 cholangiocarcinoma patients had methylation of at least one of the tumor suppressor genes analyzed. <it>p53 </it>gene mutation was found in 22 of 36 patients (61.1%). Combined <it>p53 </it>mutation and <it>DAPK, p14<sup>ARF</sup>, and/or ASC </it>methylation was detected in 14 cases (38.9%). There were statistically significant differences in the extent of pathologic biology, differentiation, and invasion between patients with combined <it>p53 </it>mutation and <it>DAPK, p14<sup>ARF</sup>, and/or ASC </it>methylation compared to those without (P < 0.05). The survival rate of patients with combined <it>DAPK, p14<sup>ARF</sup>, and ASC </it>methylation and <it>p53 </it>mutation was poorer than other patients (<it>P </it>< 0.05).</p> <p>Conclusion</p> <p>Our study indicates that methylation of <it>DAPK, p14<sup>ARF</sup>, and ASC </it>in cholangiocarcinoma is a common event. Furthermore, <it>p53 </it>mutation combined with <it>DAPK, p14<sup>ARF</sup>, and/or ASC </it>methylation correlates with malignancy and poor prognosis.</p

    Testing for Differentially-Expressed MicroRNAs with Errors-in-Variables Nonparametric Regression

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    MicroRNA is a set of small RNA molecules mediating gene expression at post-transcriptional/translational levels. Most of well-established high throughput discovery platforms, such as microarray, real time quantitative PCR, and sequencing, have been adapted to study microRNA in various human diseases. The total number of microRNAs in humans is approximately 1,800, which challenges some analytical methodologies requiring a large number of entries. Unlike messenger RNA, the majority of microRNA (60%) maintains relatively low abundance in the cells. When analyzed using microarray, the signals of these low-expressed microRNAs are influenced by other non-specific signals including the background noise. It is crucial to distinguish the true microRNA signals from measurement errors in microRNA array data analysis. In this study, we propose a novel measurement error model-based normalization method and differentially-expressed microRNA detection method for microRNA profiling data acquired from locked nucleic acids (LNA) microRNA array. Compared with some existing methods, the proposed method significantly improves the detection among low-expressed microRNAs when assessed by quantitative real-time PCR assay

    Mild Hypothermia Attenuates Mitochondrial Oxidative Stress by Protecting Respiratory Enzymes and Upregulating MnSOD in a Pig Model of Cardiac Arrest

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    Mild hypothermia is the only effective treatment confirmed clinically to improve neurological outcomes for comatose patients with cardiac arrest. However, the underlying mechanism is not fully elucidated. In this study, our aim was to determine the effect of mild hypothermia on mitochondrial oxidative stress in the cerebral cortex. We intravascularly induced mild hypothermia (33Β°C), maintained this temperature for 12 h, and actively rewarmed in the inbred Chinese Wuzhishan minipigs successfully resuscitated after 8 min of untreated ventricular fibrillation. Cerebral samples were collected at 24 and 72 h following return of spontaneous circulation (ROSC). We found that mitochondrial malondialdehyde and protein carbonyl levels were significantly increased in the cerebral cortex in normothermic pigs even at 24 h after ROSC, whereas mild hypothermia attenuated this increase. Moreover, mild hypothermia attenuated the decrease in Complex I and Complex III (i.e., major sites of reactive oxygen species production) activities of the mitochondrial respiratory chain and increased antioxidant enzyme manganese superoxide dismutase (MnSOD) activity. This increase in MnSOD activity was consistent with the upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA and protein expressions, and with the increase of Nrf2 nuclear translocation in normothermic pigs at 24 and 72 h following ROSC, whereas mild hypothermia enhanced these tendencies. Thus, our findings indicate that mild hypothermia attenuates mitochondrial oxidative stress in the cerebral cortex, which may be associated with reduced impairment of mitochondrial respiratory chain enzymes, and enhancement of MnSOD activity and expression via Nrf2 activation

    High Prevalence and Genetic Diversity of HCV among HIV-1 Infected People from Various High-Risk Groups in China

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    BACKGROUND: Co-infection with HIV-1 and HCV is a significant global public health problem and a major consideration for anti-HIV-1 treatment. HCV infection among HIV-1 positive people who are eligible for the newly launched nationwide anti-HIV-1 treatment program in China has not been well characterized. METHODOLOGY: A nationwide survey of HIV-1 positive injection drug uses (IDU), former paid blood donors (FBD), and sexually transmitted cases from multiple provinces including the four most affected provinces in China was conducted. HCV prevalence and genetic diversity were determined. We found that IDU and FBD have extremely high rates of HCV infection (97% and 93%, respectively). Surprisingly, people who acquired HIV-1 through sexual contact also had a higher rate of HCV infection (20%) than the general population. HIV-1 subtype and HCV genotypes were amazingly similar among FBD from multiple provinces stretching from Central to Northeast China. However, although patterns of overland trafficking of heroin and distinct HIV-1 subtypes could be detected among IDU, HCV genotypes of IDU were more diverse and exhibited significant regional differences. CONCLUSION: Emerging HIV-1 and HCV co-infection and possible sexual transmission of HCV in China require urgent prevention measures and should be taken into consideration in the nationwide antiretroviral treatment program
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