Predicting nodal influence via local iterative metrics.

Nodal spreading influence is the capability of a node to activate the rest of the network when it is the seed of spreading. Combining nodal properties (centrality metrics) derived from local and global topological information respectively has been shown to better predict nodal influence than using a single metric. In this work, we investigate to what extent local and global topological information around a node contributes to the prediction of nodal influence and whether relatively local information is sufficient for the prediction. We show that by leveraging the iterative process used to derive a classical nodal centrality such as eigenvector centrality, we can define an iterative metric set that progressively incorporates more global information around the node. We propose to predict nodal influence using an iterative metric set that consists of an iterative metric from order 1 to K produced in an iterative process, encoding gradually more global information as K increases. Three iterative metrics are considered, which converge to three classical node centrality metrics, respectively. In various real-world networks and synthetic networks with community structures, we find that the prediction quality of each iterative based model converges to its optimal when the metric of relatively low orders ( K ∼ 4 ) are included and increases only marginally when further increasing K. This fast convergence of prediction quality with K is further explained by analyzing the correlation between the iterative metric and nodal influence, the convergence rate of each iterative process and network properties. The prediction quality of the best performing iterative metric set with K = 4 is comparable with the benchmark method that combines seven centrality metrics: their prediction quality ratio is within the range [ 91 % , 106 % ] across all three quality measures and networks. In two spatially embedded networks with an extremely large diameter, however, iterative metric of higher orders, thus a large K, is needed to achieve comparable prediction quality with the benchmark.

Acoustic information masking effects of natural sounds on traffic noise based on psychological health in open urban spaces.

The use of existing resources, such as natural sounds, to promote the mental health of citizens is an area of research that is receiving increasing attention. This research contributes to existing knowledge by combining a field psychological walk method and an experimental acoustic control method to compare the acoustic information masking effects of water and birdsong sounds on traffic noise based on the psychological health responses of 30 participants to such effects. The influence of traffic noise and contextual sounds on the psychological health of participants identified the potential of natural sounds in the acoustic information masking of traffic noise. Furthermore, it was found that 65.0 dBA water sounds did not mask 60.0 dBA traffic noises. However, 45.0 dBA birdsong sounds did mask it, but this effect was not significant. Additionally, contextual factors with and without crowd activity sounds were not significant in influencing psychological health through birdsong. This study contributes to public health cost savings. It may also guide the development of new ideas and methods for configuring open urban spaces according to public health needs.

Application and Optimization of the Rheological Model for a Hydrophobically Associating Dendrimer Polymer.

Polymer flooding is one of the most important enhancing oil recovery (EOR) technologies in the world. With the optimization of polymer synthesis, the performance of polymer solutions has been greatly improved, which can adapt to more complex oil and gas reservoirs. However, with the continuous improvement of the properties of polymer solutions, the elastic property of polymer solutions is significantly improved, and the rheological law has also changed. This series of changes affects the application of polymer flooding reservoir numerical simulation technology. Therefore, constructing an accurate description model and precise limitation conditions is particularly important. The rheological curve with a wide shear range (0.1~10,000 s-1) and the viscoelasticity of the two polymers (partially hydrolysed polyacrylamide (HPAM) and dendritic hydrophobic association polymer (DHAP)) were analyzed and tested by a rotating rheometer. The results showed that under the experimental conditions, the rheological curve of both polymers can be described by the Carreau rheological model. Meanwhile, the structural viscosity of the hydrophobically associating polymer solution (DHAP) greatly improved the elasticity of the solution and led to the change of elastic modulus. Considering the influence of elastic characteristics on the rheological curve, the relaxation time spectrum derived from small vibration experimental data was used to limit the characteristic relaxation time, that is, the value range of λ. It was observed that the experimental data were highly matched with the nonlinear regression fitting curve of the Carreau rheological model. Therefore, the relationship between different test parameters should be fully considered while studying the rheological constitutive equation of viscoelastic fluid, so as to optimize and improve the equation of it.

Mitigate SIR epidemic spreading via contact blocking in temporal networks.

Progress has been made in how to suppress epidemic spreading on temporal networks via blocking all contacts of targeted nodes or node pairs. In this work, we develop contact blocking strategies that remove a fraction of contacts from a temporal (time evolving) human contact network to mitigate the spread of a Susceptible-Infected-Recovered epidemic. We define the probability that a contact c(i, j, t) is removed as a function of a given centrality metric of the corresponding link l(i, j) in the aggregated network and the time t of the contact. The aggregated network captures the number of contacts between each node pair. A set of 12 link centrality metrics have been proposed and each centrality metric leads to a unique contact removal strategy. These strategies together with a baseline strategy (random removal) are evaluated in empirical contact networks via the average prevalence, the peak prevalence and the time to reach the peak prevalence. We find that the epidemic spreading can be mitigated the best when contacts between node pairs that have fewer contacts and early contacts are more likely to be removed. A strategy tends to perform better when the average number contacts removed from each node pair varies less. The aggregated pruned network resulted from the best contact removal strategy tends to have a large largest eigenvalue, a large modularity and probably a small largest connected component size.

The Influence of Audio-Visual Interactions on Psychological Responses of Young People in Urban Green Areas: A Case Study in Two Parks in China.

Audio-visual interactions in green spaces are important for mental health and wellbeing. However, the influence of audio-visual interactions on psychological responses is still less clear. This study introduced a new method, namely the audio-visual walk (AV-walk), to obtain data on the audio-visual context, audio-visual experiences, and psychological responses in two typical parks, namely Cloves Park and Music Park in Harbin, China. Some interesting results are as follows: First, based on Pearson's correlation analysis, sound pressure level and roughness were significantly correlated with psychological responses in Cloves Park (p < 0.05). Second, the results of stepwise regression models showed the impact intensity of acoustic comfort was 1.64-1.68 times higher than that of visual comfort on psychological responses of emotion dimension, while visual comfort was 1.35-1.37 times higher than acoustic comfort on psychological responses of cognition dimension in Music Park. In addition, an orthogonal analysis diagram explained the influence of audio-visual interactions on psychological responses of young people. The audio-visual context located beside the waterscape with a relatively higher level of acoustic and visual comfort was the most cheerful (2.60), relaxed (2.45), and energetic (2.05), while the audio-visual context close to an urban built environment tended to be both acoustically and visually uncomfortable, and the psychological state was decreased to the most depressed (-0.25), anxious (-0.75), fatigued (-1.13) and distracted (-1.13).

Chaetocin reactivates the lytic replication of Epstein-Barr virus from latency via reactive oxygen species.

Oxidative stress, regarded as a negative effect of free radicals in vivo, takes place when organisms suffer from harmful stimuli. Some viruses can induce the release of reactive oxygen species (ROS) in infected cells, which may be closely related with their pathogenicity. In this report, chaetocin, a fungal metabolite reported to have antimicrobial and cytostatic activity, was studied for its effect on the activation of latent Epstein-Barr virus (EBV) in B95-8 cells. We found that chaetocin remarkably up-regulated EBV lytic transcription and DNA replication at a low concentration (50 nmol L-1). The activation of latent EBV was accompanied by an increased cellular ROS level. N-acetyl-L-cysteine (NAC), an ROS inhibitor, suppressed chaetocin-induced EBV activation. Chaetocin had little effect on histone H3K9 methylation, while NAC also significantly reduced H3K9 methylation. These results suggested that chaetocin reactivates latent EBV primarily via ROS pathways.

Staphylococcus enterotoxin B-induced T cells can efficaciously protect against type 1 diabetes in non-obese diabetic mice.

Type 1 diabetes (T1D), an autoimmune disease, can be protected against by natural killer T (NKT) cells. Several attempts demonstrate that NKT cells also can be produced by inducing with Staphylococcus enterotoxin B (SEB) in addition to its classical activated antigen α-galactosylceramide. Here, we examined a potential usage of SEB-induced T (SEB-T) cells for the treatment of T1D. We established the immunophenotypes of SEB-T cells via flow cytometry, and in consequence, enriched in CD8(+)NKT cells after SEB stimulated. A high level of transforming growth factor ß (TGF-ß), detected by RT-PCR and ELISA, was first observed to be expressed and secreted by these SEB-T cells. Mixed lymphocyte reactions indicated that SEB-T cells could not produce a response to mitogens and allogeneic lymphocyte, and can inhibit lymphocytes response to mitogens. In an animal model, our data indicated that infusion of SEB-T cells in non-obese diabetic mice was well tolerated and could ameliorate hyperglycemia and maintain the blood glucose nearly on normal level until sacrifice. Strikingly, infusion of SEB-T cells resulted in an increase in the serum TGF-ß level. These data raise the possibility that SEB-T cells can protect against T1D, which is associated with NKT cells generated in these SEB-induced cells.

Protective effects of losartan in mice with chronic viral myocarditis induced by coxsackievirus B3.

AIM: To investigate whether losartan has protective effects in mice with chronic viral myocarditis induced by coxsackievirus B3 (CVB3). MAIN METHODS: Thirty two male Balb/c mice were intraperitoneally injected with CVB3 (10×TCID50) to induce chronic viral myocarditis (CVM). Losartan at 12.5mg/kg (n=16) or normal saline (n=16) were orally administered daily for 28 days to these mice. Uninfected mice (n=6) were used as controls. On day 29, all mice underwent anesthesia and echocardiography prior to sacrifice. Serum IL-17, IL-4, IFN-γ and TNF-α levels were measured by enzyme-linked immunosorbent assay, and cardiac tissues were histologically examined after hematoxylin & eosin staining. In addition, the effect of losartan on the virus titers in primary cultured neonatal rat cardiomyocytes infected with CVB3 was measured on Hep-2 cells at 72 h post infection. KEY FINDINGS: Mice infected with CBV3 had significantly increased mortality, heart/body weight ratios, necrosis and inflammatory scores and decreased cardiac ejection fractions, compared with the controls (all P<0.05). Losartan significantly decreased mortality from 40.0% to 12.5%, heart/body weight ratios from 7.08 ± 2.17 to 4.15 ± 0.99, and necrosis and inflammatory scores from 3.33 ± 0.50 to 2.50 ± 0.65 (all P<0.05), and increased ejection fractions from 55.80 ± 9.25 to 72.31 ± 12.15 (P<0.05). Losartan significantly enhanced IL-4, and decreased IFN-γ, TNF-α and IL-17 (all P<0.05). In the in vitro experiment, losartan had no influence on virus titers. SIGNIFICANCE: Losartan protects mice against CVB3-induced CVM, most likely through upregulating Th2 responses, and down-regulating Th1 and Th17 responses.

[Study on the stability of the anergic CD8(+);NKT cells in vitro].

AIM: To study the CD8(+);NKT cell stability function. METHODS: Splenic lymphocytes from C57BL/J mice were treated with Staphylococcal enterotoxin B (SEB) and then cultured in vitro. Day 10, 20, 30 and freezen effector cells were harvested and used. The cells were cultured in medium containing ConA and LPS for 72 hours and measured their response to mitogens. The inhibitory action of the effector cells were examined. The effector cells were co-cultured with normal lymphocytes and above mitogens for 72 hours. The cells proliferation was assessed with MTT method. The effector cells were cultured with heterogenic lymphocytes and were assessed with MTT method. The NKT cell subsets among these effector cells were analyzed by flow cytometry. RESULTS: The response of these effector cells to ConA and LPS was significantly decreased compared with that of normal lymphocytes. The A values of cell proliferation were decreased from 0.67 and 0.61 to 0.30 and 0.31, 0.28 and 0.20, 0.26 and 0.24, 0.22 and 0.23 (P<0.05, n=3). The inhibitory ability of effector cells aginst the response of normal lymphocytes to ConA and LPS were clearly observed. They inhibited the response of normal lymphocytes to above mitogens. And the A values of cell proliferation were decreased from 0.67 and 0.61 to 0.33 and 0.39, 0.30 and 0.43, 0.36 and 0.43, 0.26 and 0.29(P<0.05, n=3). The response of effector cells to heterogenic lymphocytes was significantly decreased compared with normal lymphocytes. The A values of cell proliferation were decreased from 0.70 to 0.42, 0.42 and 0.54 on day 20, 30 and freezen effector cells respectively(P<0.05, n=3). The CD8(+);NKT cell subsets among these effector cells with tolerance function were significantly increased(P<0.05, n=3). CONCLUSION: The anergic CD8(+);NKT cells could culture in vitro. And the anergic function of these cells were still existing.

[Identification of cell division of CD8+ NKT cells in vitro].

AIM: To measure the in vitro cell division ability of CD8(+);NKT cells by CFSE staining and flow cytometry(FCM). METHODS: Fresh spleen lymphocytes of C57BL/J mice were separated and stained with CFSE, and then stimulated by ConA and LPS for 3 d, and by SEB for 5 d and 10 d respectively. The stimulated cells were harvested and analyzed for CD69 expression on the cell surface and the ability of cell division using FCM. The SEB-activated effector cells for 10 d further stimulated with IL-2 for the consecutive 10 days, and were analyzed for their cell division ability, CD69 expression and NKT cell subsets by FCM. RESULTS: ConA, LPS and SEB stimulated the proliferation of spleen cells. ConA and LPS made the cells divide 3 times within 3 d, and increased CD69 expression up to 74.19% and 41.56% respectively. SEB made the cells divide 5 times within 5 d and 7 times within 10 d respectively, with increased CD69 expression of 32.09% and 48.66% respectively. Ten-day IL-2 stimulation of SEB-activated cells caused population expansion for 7 times with the CD8(+);NKT cell subsets significantly increased from 0.36% to 38.58% and CD69 expression significantly increased from 0.11% to 83.74%. CONCLUSION: The SEB-activated CD8(+);NKT cells proliferated in vitro and their cell division capability could be determined by CFSE staining and FCM.