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Tao Zhou

Publications and source records attributed to Tao Zhou.

At least 37 records · Page 2Linked to original sources
PubMed2006

Traffic dynamics based on local routing protocol on a scale-free network.

We propose a packet routing strategy with a tunable parameter based on the local structural information of a scale-free network. As free traffic flow on the communication networks is key to their normal and efficient functioning, we focus on the network capacity that can be measured by the critical point of phase transition from free flow to congestion. Simulations show that the maximal capacity corresponds to alpha= -1 in the case of identical nodes' delivering ability. To explain this, we investigate the number of packets of each node depending on its degree in the free flow state and observe the power law behavior. Other dynamic properties including average packets traveling time and traffic load are also studied. Inspiringly, our results indicate that some fundamental relationships exist between the dynamics of synchronization and traffic on the scale-free networks.

Journal Article↗
PubMed2006

Sequestering ErbB2 in endoplasmic reticulum by its autoinhibitor from translocation to cell surface: an autoinhibition mechanism of ErbB2 expression.

ErbB2 is differentially overexpressed in tumor versus host tissues, suggesting that an autoregulation mechanism may modulate the expression of ErbB2 and control cell growth. A truncated ErbB2 extracellular domain, herstatin has been shown to bind to ErbB2 and inhibit the growth of tumor cells expressing ErbB2. In the present study, the interaction of herstatin and ErbB2 in vivo was observed by confocal microscopy. The aggregation of ErbB2 and herstatin was found in endoplasmic reticulum (ER). The decrease of ErbB2 on the cell surface was accompanied with the increased colocalization of ErbB2 and herstatin in the cytoplasm, suggesting that the formation of ErbB2/herstatin complex may prevent transit from ER to cell surface of ErbB2. The formation of ErbB2 and herstatin complex was further confirmed by immunoprecipitation. The results demonstrate that sequestering ErbB2 molecules intracellularly by herstatin may be a possible mechanism of the cell growth inhibition.

Animals↗
PubMed2006

Proteomics analysis reveals insight into the mechanism of H-Ras-mediated transformation.

We implemented a proteomics approach to the systematical analysis of the alterations in the proteome of NIH3T3 cells transformed by oncogenic H-RasV12. Forty-four proteins associated with Ras-mediated transformation have been identified, and 28 proteins were not previously reported. RT-PCR analysis showed that approximately 44% of target proteins identified showed concomitant changes in mRNA abundance. A principal finding was the up-regulation of gankyrin, which was the first evidence to show that gankyrin pathway was implicated in Ras-activated transformation.

Animals↗
PubMed2006

Neurons derived from PC12 cells have the potential to develop synapses with primary neurons from rat cortex.

Neuron transplantation is considered to be a promising therapeutic method to replace functions lost due to central nervous system (CNS) damage. However, little is known about the extent to which implanted neuron-like cells can develop into mature neurons and acquire essential properties, and especially formation of synapses with host neurons. In this investigation we seeded PC12 cells labeled with GFP into primary cultured neurons isolated from rat cerebral cortex to build a co-culture system, and then induced the PC12 cells to differentiate into neuron-like cells with NGF. Seven days later, we observed the relationship between the PC12-derived neurons and primary neurons using FM1-43 imaging and immunoelectron microscopy, and found that GFP-labeled neurons could form typical synapses with host primary neurons. These observations showed that immigrant neurons differentiated from PC12 cells could develop into mature neurons and could form intercellular contacts with host neurons. Both the immigrant and host neurons could construct neuronal networks in vitro.

Animals↗
PubMed2006

[Effects of hydrocortisone on circulating and intramyocardial inflammatory mediators in severe septic rats with myocardial injury induced by Escherichia coli].

OBJECTIVE: Severe sepsis and septic shock remain the most common cause of death in intensive care units. The main causes of death in sepsis are the cardiac dysfunction and hypotension resistant to cateolamines. The prevalence of relative adrenal insufficiency in severe sepsis and septic shock was estimated at about 32%-51%. Several meta-analysis demonstrated that high-dose glucocorticoids decreased survival during sepsis, while stress doses of corticosteroids may benefit these patients. The exact reason for such widely divergent outcome produced by different doses of corticosteroid is still not understood. Therefore, the study was undertaken to observe the effects of different doses of hydrocortisone (HC) on circulating and intramyocardial inflammatory mediators in severe septic rats with myocardial injury induced by Escherichia coli (E. coli). METHODS: The model was established by two injections of inactivated E. coli Forty male Wistar rats were randomly divided into five groups: high-dose of HC group (150 mg/kg), medium-dose group (20 mg/kg), low-dose group (6 mg/kg), model group (NS substituted for HC), and control group (NS for E. coli and HC). Each group had eight rats. After 2 hours of treatment, specimens were collected to measure serum cardiac troponin I (cTnI), tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), nitric oxide (NO) and total NO synthase (NOS). NO and total NOS in myocardial homogenate were also detected. The expression of inducible NOS (iNOS) of myocytes was investigated. RESULTS: All the above-mentioned markers in model group significantly higher than those in control group. After HC injection, serum cTnI concentrations in low-dose group decreased to normal values compared to that of model group, while in another two HC groups, the concentrations were higher than those in model group. TNF-alpha level was not significantly influenced. But IL-1beta level declined to normal values, being prominent in low-dose HC group. Neither high-dose nor middle-dose HC could lower serum NO or total NOS, but low-dose HC could greatly inhibit both NO and NOS levels (P < 0.05). There was no significant difference in the level of NO and total NOS of myocardial homogenate between left and right ventricles. There was no iNOS expression by normal myocardium, while the expression in model group was significantly increased. After HC injection, the iNOS expressions by myocardium in three HC groups were weaker than those in model group. The intensity of iNOS signals became weak with the decrease in HC dose. CONCLUSION: Different doses of HC might exert different effects on circulating and intramyocardial inflammatory mediators in severely septic rats with myocardial injury induced by E. coli. Low-dose HC could significantly inhibit such mediators as well as iNOS expression by cardiomyocytes. The results suggest that low dose HC exert protective effect on myocardial injury of severely septic rats.

Animals↗
PubMed2006

[Clinical manifestation and laryngoscopic characteristics of laryngeal tuberculosis].

OBJECTIVE: To evaluate the clinical manifestations of laryngeal tuberculosis and its laryngoscopic characteristics. METHOD: Clinical analysis of 36 laryngeal tuberculosis cases confirmed pathologically was carried out retrospectively. RESULTS: The patients' ages ranged from 19 to 78 years old (median 39.5 years old). The male to female ratio was 1.8 to 1. The most frequent chief complaint was hoarseness (83.3%). The true vocal cord and the false vocal cord were usually found involved by fibrolaryngoscope observations. The lesions appearances were mainly the proliferation such as nodules or granules. The laryngostroboscopy demonstrated that the wave of the mucosa and vibration of the involved vocal cords were markedly reduced or disappeared. Among 24 patients with multiple lesions in the larynx, 19 (79.2%) had active pulmonary tuberculosis,while 9 (75.0%) had normal lung status among 12 patients with single lesions in the throat. All the patients received a full course of antituberculosis treatment. The results of the antituberculous medication was satisfactory in all 26 cases patients who can be followed up, while 10 cases were lost for the follow-up. CONCLUSIONS: The local clinical manifestations of laryngeal tuberculosis is nonspecific, while the whole manifestation is not apparent. The lesions commonly involve the true vocal cord and the false vocal cord. It can even occur without pulmonary tuberculosis.

Adult↗
PubMed2006

[Application of active breathing control system to precise radiotherapy for non-small cell lung cancer].

BACKGROUND & OBJECTIVE: Breathing is one major factor which affects the dose used in the treatment of non-small cell lung cancer (NSCLC). This study was to observe the influence of active breathing control (ABC) system on the motion of primary tumor of non-small cell lung cancer and investigate the effect of ABC on the reduction of radioactive damage of lungs during precise radiotherapy. METHODS: Seven patients with stage IIIA and IV peripheral lung cancer, whose pathology were either squamous cell carcinoma or adenocarcinoma, were enrolled. The patients receiving three-dimensional conformal radiotherapy controlled by ABC system held their breath when their inspiratory volume reached 80% of the maximum. The moving ranges of tumor in intra-and inter-fractions during radiotherapy were calculated respectively. The tumor moving ranges of patients who accepted repeated CT scans when breathing freely in the same position were calculated. Internal margin, V2, D(mean), volume of GTV and total volume of bilateral lung were calculated by treatment planning system and compared by t-test. RESULTS: The mean ranges in left-right (X), superior-inferior (Y) and cranial-caudal (Z)directions were(0.79+/-0.45)mm, (0.98+/-0.52)mm, (0.50+/-0.75)mm in intra-fractional radiotherapy and (0.91+/-0.69)mm, (1.02+/-0.77)mm, (0.74+/-1.0)mm in inter-fractional radiotherapy respectively when patients used ABC system; while the ranges were (1.09+/-0.61)mm, (1.71+/-0.82)mm, (2.73+/-1.08)mm respectively when patients breathed freely. V20 were (10.0+/-3.7)% and (17.0+/-6.5)% (P=0.015); D(mean) were (539+/-247)cGy and (844+/-390)cGy (P=0.012); the volumes of GTV were (26.1+/-22)cm(3) and (30.0+/-23.9)cm(3) (P=0.02), and total bilateral lung volume were (3522.8+/-1020)cm(3) and (3240.7+/-876.7)cm(3) (P=0.045) respectively under ABC and free breathing condition. CONCLUSIONS: The tumor moving ranges and internal margins are reduced by holding the patients' breath by ABC system, which reduces the volume of normal tissues around peripheral lung tumor during radiotherapy. In addition, total lung volumes are enlarged when patients holding their breath while inhaling, which can reduce the density of irradiated lungs, and thus the incidence of radioactive lung damage is decreased accordingly.

Adult↗
PubMed2005

Advanced information feedback in intelligent traffic systems.

The optimal information feedback is very important to many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. As to traffic flow, a reasonable real-time information feedback can improve the urban traffic condition by providing route guidance. In this paper, the influence of a feedback strategy named congestion coefficient feedback strategy is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other two information feedback strategies, i.e., travel time and mean velocity.

Journal Article↗
PubMed2005

Enhanced synchronizability by structural perturbations.

In this Brief Report, we investigate the collective synchronization of a system of coupled oscillators on a Barabási-Albert scale-free network. We propose an approach of structural perturbations aiming at those nodes with maximal betweenness. This method can markedly enhance the network synchronizability, and is easy to realize. The simulation results show that the eigenratio will sharply decrease by one-half when only 0.6% of those hub nodes occur under three-division processes when the network size . In addition, the present study also provides numerical evidence that the maximal betweenness plays a major role in network synchronization.

Journal Article↗
PubMed2005

High affinity iron(III) scavenging by a novel hexadentate 3-hydroxypyridin-4-one-based dendrimer: synthesis and characterization.

The synthesis of a novel iron(III)-selective hydroxypyridinone hexadentate-terminated dendritic chelator based on a benzene tricarbonyl core polyamine dendrimer is described. The iron-chelating ability of the dendritic chelator was demonstrated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and UV-vis spectroscopy. The physicochemical properties of the isolated hexadentate unit were also investigated. The dendrimer was found to possess an extremely high affinity for iron(III), namely logK=34.8, pFe3+=30.6.

Hydrogen-Ion Concentration↗
PubMed2005

Self-organized Boolean game on networks.

A model of a Boolean game with only one free parameter p that denotes the strength of local interaction is proposed wherein each agent acts according to the information obtained from his neighbors in the network, and those in the minority are rewarded. The simulation results indicate that the dynamic of the system is sensitive to network topology, whereby the network of larger degree variance, i.e., the system of greater information heterogeneity, leads to less system profit. The system can self-organize to a stable state and perform better than the random choice game, although only the local information is available to the agents. In addition, in heterogeneity networks, the agents with more information gain more than those with less information for a wide extent of interaction strength p.

Journal Article↗
PubMed2005

Mutual selection model for weighted networks.

For most networks, the connection between two nodes is the result of their mutual affinity and attachment. In this paper, we propose a mutual selection model to characterize the weighted networks. By introducing a general mechanism of mutual selection, the model can produce power-law distributions of degree, weight, and strength, as confirmed in many real networks. Moreover, we also obtained the nontrivial clustering coefficient C, degree assortativity coefficient r, and degree-strength correlation depending on a single parameter m. These results are supported by present empirical evidence. Studying the degree-dependent average clustering coefficient C(k) and the degree-dependent average nearest neighbors' degree k(nn)(k) also provide us with a better description of the hierarchies and organizational architecture of weighted networks.

Journal Article↗
PubMed2005

Continuous extremal optimization for Lennard-Jones clusters.

We explore a general-purpose heuristic algorithm for finding high-quality solutions to continuous optimization problems. The method, called continuous extremal optimization (CEO), can be considered as an extension of extremal optimization and consists of two components, one which is responsible for global searching and the other which is responsible for local searching. The CEO's performance proves competitive with some more elaborate stochastic optimization procedures such as simulated annealing, genetic algorithms, and so on. We demonstrate it on a well-known continuous optimization problem: the Lennard-Jones cluster optimization problem.

Journal Article↗
PubMed2005

Maximal planar networks with large clustering coefficient and power-law degree distribution.

In this article, we propose a simple rule that generates scale-free networks with very large clustering coefficient and very small average distance. These networks are called random Apollonian networks (RANs) as they can be considered as a variation of Apollonian networks. We obtain the analytic results of power-law exponent gamma=3 and clustering coefficient C= (46/3)-36 ln 3/2 approximately 0.74, which agree with the simulation results very well. We prove that the increasing tendency of average distance of RANs is a little slower than the logarithm of the number of nodes in RANs. Since most real-life networks are both scale-free and small-world networks, RANs may perform well in mimicking the reality. The RANs possess hierarchical structure as C(k) approximately k(-1) that are in accord with the observations of many real-life networks. In addition, we prove that RANs are maximal planar networks, which are of particular practicability for layout of printed circuits and so on. The percolation and epidemic spreading process are also studied and the comparisons between RANs and Barabási-Albert (BA) as well as Newman-Watts (NW) networks are shown. We find that, when the network order N (the total number of nodes) is relatively small (as N approximately 10(4)), the performance of RANs under intentional attack is not sensitive to N , while that of BA networks is much affected by N. And the diseases spread slower in RANs than BA networks in the early stage of the susceptible-infected process, indicating that the large clustering coefficient may slow the spreading velocity, especially in the outbreaks.

Journal Article↗