Critical size of ego communication networks

With the help of information and communication technologies, studies on the overall social networks have been extensively reported recently. However, investigations on the directed Ego Communication Networks (ECNs) remain insufficient, where an ECN stands for a sub network composed of a centralized individual and his/her direct contacts. In this paper, the directed ECNs are built on the Call Detail Records (CDRs), which cover more than 7 million people of a provincial capital city in China for half a year. Results show that there is a critical size for ECN at about 150, above which the average emotional closeness between ego and alters drops, the balanced relationship between ego and network collapses, and the proportion of strong ties decreases. This paper not only demonstrate the significance of ECN size in affecting its properties, but also shows accordance with the "Dunbar's Number". These results can be viewed as a cross-culture supportive evidence to the well-known Social Brain Hypothesis (SBH).Comment: 6 pages, 4 figures, 1 tabl

Organic geochemistry evidence for wildfire and elevated pO2 at the Frasnian–Famennian boundary

The Devonian experienced radiations of plants and animals, as well as a major mass extinction event during the Frasnian–Famennian (Fsingle bondF) interval. Proposed triggers have been linked to volcanism, extraterrestrial impact, sea-level fluctuations, and climate cooling, etc. However, the nature of the wildfires and its role in the biotic evolution have been rarely investigated for the Fsingle bondF interval. Here, we report organic geochemistry proxies (e.g., polycyclic aromatic hydrocarbons, PAHs) in three sections from New York (USA) to further investigate the wildfire activity and its potential link with the environmental and biotic perturbations around the Fsingle bondF interval. The studied intervals are dominated by three-ring PAHs which display an increasing abundance stratigraphically towards the Fsingle bondF boundary (FFB). An increase of 6-ring over 3-ring PAHs across the FFB is also observed for the studied sections, indicating elevated burning temperature. Additionally, slightly increased plant wax abundance and average chain length values and relatively constant Pr/Ph ratios are observed. Collectively, these results propose an increased burning frequency over the Fsingle bondF interval caused by elevated pO2 level, rather than a change in aridity. Terrestrial input only slightly increased across the FFB, and there is limited evidence for ocean anoxia. This correlates with the hypothesis that pCO2 drawdown and climate cooling could have been a driving mechanism of the Fsingle bondF biocrisis

Effects of painful stimulation and acupuncture on attention networks in healthy subjects

Pain is a subjective sensory and emotional experience, and it has been reported that many different brain regions are regulated by pain, and that pain can impact attention. Acupuncture is an important treatment component of Chinese traditional medicine, and has been used for thousands of years to treat a wide variety of conditions. Although several studies have shown that acupuncture improves consciousness, the precise impact of both acupuncture and painful stimulation on attention is unclear. Are all of the attention networks modulated, or do these stimuli act on a specific network? Is the effect of painful stimulation similar to that of acupuncture? We administered the attention network test to 30 participants (15 males) to investigate the relative efficiencies of three independent attention networks (alerting, orienting, and executive control networks) under three conditions: baseline, after painful stimulation, and after acupuncture. The degree of pain experienced was assessed on a horizontally oriented visual analogue scale. The results showed that painful stimulation and acupuncture had similar effects on the orienting and executive control networks; however, there was a significantly different effect between the three conditions on the alerting network. In conclusion, (1) painful stimulation can selectively impact attention; (2) acupuncture can also selectively impact attention; i.e., both have selective influences on the alerting and executive control networks, but not on the orienting network; (3) the effects of acupuncture and painful stimulation are not identical. The mechanisms by which painful stimulation and acupuncture influence attention warrant further research

Role of reactive oxygen species in epithelial­-mesenchymal transition and apoptosis of human lens epithelial cells

AIM: To investigate the role of reactive oxygen species (ROS) in epithelial–mesenchymal transition (EMT) and apoptosis of human lens epithelial cells (HLECs). METHODS: Flow cytometry was used to assess ROS production after transforming growth factor β2 (TGF-β2) induction. Apoptosis of HLECs after H2O2 and TGF-β2 interference with or without ROS scavenger N-acetylcysteine (NAC) were assessed by flow cytometry. The corresponding protein expression levels of the EMT marker α-smooth muscle actin (α-SMA), the extracellular matrix (ECM), marker fibronectin (Fn), and apoptosis-associated proteins were detected by using Western blotting in the presence of an ROS scavenger (NAC). Wound-healing and Transwell assays were used to assess the migration capability of HLECs. RESULTS: TGF-β2 stimulates ROS production within 8h in HLECs. Additionally, TGF-β2 induced HLECs cell apoptosis, EMT/ECM synthesis protein markers expression, and pro-apoptotic proteins production; nonetheless, NAC treatment prevented these responses. Similarly, TGF-β2 promoted HLECs cell migration, whereas NAC inhibited cell migration. We further determined that although ROS initiated apoptosis, it only induced the accumulation of the EMT marker α-SMA protein, but not COL-1 or Fn. CONCLUSION: ROS contribute to TGF-β2-induced EMT/ECM synthesis and cell apoptosis of HLECs; however, ROS alone are not sufficient for EMT/ECM synthesis