Reconstructing community structure of online social network via user opinions.

User opinion affects the performance of network reconstruction greatly since it plays a crucial role in the network structure. In this paper, we present a novel model for reconstructing the social network with community structure by taking into account the Hegselmann-Krause bounded confidence model of opinion dynamic and compressive sensing method of network reconstruction. Three types of user opinion, including the random opinion, the polarity opinion, and the overlap opinion, are constructed. First, in Zachary's karate club network, the reconstruction accuracies are compared among three types of opinions. Second, the synthetic networks, generated by the Stochastic Block Model, are further examined. The experimental results show that the user opinions play a more important role than the community structure for the network reconstruction. Moreover, the polarity of opinions can increase the accuracy of inter-community and the overlap of opinions can improve the reconstruction accuracy of intra-community. This work helps reveal the mechanism between information propagation and social relation prediction.

Network reconstruction of social networks based on the public information.

The structure of a social network plays a crucial role for dynamic analysis, which is invisible in most scenes. In this paper, we present a model for reconstructing the social network by taking into account the public opinion diffusion dynamic model for specific agenda. First, the initial polarity attitude of users i for the agenda, oi, is set in the range [-1,1], where negative and positive attitudes are set as -1 and 1, respectively, while 0 means that user i's attitude is uncertain. Second, we present an optimization model for detecting the relationship among each pair of users based on the generated public observable information. The experimental results for four synthetic networks and three real-world social networks show that the reconstruction accuracy depends on the uncertainty of the initial attitudes greatly. This work is helpful for revealing the structure of social networks in terms of public information.

Desulphurization characteristics of bamboo charcoal from sulfur solution.

Sulfur powder and sulfur dioxide (SO2) often floated in air, produced acid rain and algal blooms, and could cause diseases. Bamboo charcoal could have adsorption and filtration properties. In order to figure out the optimal adsorption condition and the intrinsic change of the bamboo charcoal, five chemicals were adsorbed by bamboo charcoal and were analyzed by FT-IR. Fe2(SO4)3's, Na2SO4's, Na2S2O8's, S's, and Na2SO3's optimal adsorption condition was the concentration of 19 g/1000 g and stir time of 20 min, 21 g/1000 g and stir time of 60 min, 7 g/1000 g and stir time of 120 min, 11 g/1000 g and stir time of 120 min, 21 g/1000 g and stir time of 60 min, respectively. FT-IR spectra showed that for FT-IR spectra of Fe2(SO4)3, the transmissivity of the peaks at 3435 cm-1 and 2925 cm-1 achieved the maximum for 60 min and the concentration was 19 g/1000 g, the transmissivity of the peaks at 1630 cm-1, 1060 cm-1 and 660 cm-1 achieved the maximum for 60 min and the concentration was 7 g/1000 g. For FT-IR spectra of Na2SO4, the transmissivity of the peaks at 1630 cm-1, 1060 cm-1 and 660 cm-1 achieved the maximum for 20 min and the concentration was 13 g/1000 g. For FT-IR spectra of Na2S2O8, the transmissivity of the peaks at 3435 cm-1, 2925 cm-1, 1630 cm-1 and 1060 cm-1 achieved the maximum for 120 min and the concentration was 19 g/1000 g. For FT-IR spectra of S, the transmissivity of the peaks at 3435 cm-1, 2925 cm-1, 1630 cm-1 and 1060 cm-1 achieved the maximum for 20 min and the concentration was 11 g/1000 g, 17 g/1000 g and 21 g/1000 g. For FT-IR spectra of Na2SO3, the transmissivity of the peaks at 3435 cm-1 achieved the maximum for 120 min and the concentration was 5 g/1000 g, the transmissivity of the peaks at 2925 cm-1, 1630 cm-1 and 1060 cm-1 achieved the maximum for 120 min and the concentration was 11 g/1000 g. In these states, the number of the transmissivity of the maximum peaks is the largest.

Establishment of reverse direct ELISA and its application in screening high-affinity monoclonal antibodies.

Traditionally monoclonal antibody (MAb) titer is determined by indirect enzyme-linked immunosorbent assay (ELISA), which is primarily used to evaluate the quality of MAbs. In this study, the titer and affinity of a group of MAbs against ovalbumin (OVA) were tested by indirect ELISA and the ELISA method reported previously. Data showed that there may be great differences between the indirect ELISA antibody titer and affinity value of MAbs. For the first time, a simple and effective reverse direct ELISA (RD-ELISA) was established for the detection of high-affinity MAbs. Among the group of MAbs to OVA, a certain proportion of antibodies with high affinity but low indirect ELISA titer do exist and can be clearly and efficiently detected by RD-ELISA. This study demonstrates that RD-ELISA is an effective method for high-affinity MAb screening.

WITHDRAWN: Lipid peroxidation and antioxidant defense systems in tissues of a lizard (Phrynocephalus przewalskii) during hibernation.

This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

[Fusion expression and identification of angiostatin and endostatin in E. coli BL21(DE3)].

Angiostatin(AS) and endostatin(ES) are both potent endogenous angiogenesis inhibitors, and the combination of AS and ES has been shown to have synergistic antiangiogenic effects. Here we report the fusion protein AS-ES expressed in E. coli which has antiangiogenic effects. At first, AS and ES genes were cloned respectively through RT-PCR, then fusion gene was made through gene splicing ,finally pET-42 (b)/AS-ES expression plasmid was constructed and transduced in E. coli BL21 (DE3). Target protein was in form of inclusion body,the rate of expression was about 14%, and MW about 65KD. Western blotting assay showed expressed protein had specific immune reaction to both the antibodies of AS and ES. The expressed protein which was refolded and purified through heparin affinity chromatography had antiangiogenic effect to vessels on chicken embryo chorioallantoic membrane. The results show that fusion protein AS-ES was expressed successfully in E. coli, and the expressed protein,which was renatured and purified, had immuno-reactivity to anti-AS and anti-ES in Western blotting and angiogenesis inhibition activity.

Protective effects of polysaccharide from Euphorbia kansui (Euphorbiaceae) on the swimming exercise-induced oxidative stress in mice.

The present study examined the effects of derivatives of galactosides and glucosides in a polysaccharide extract from Euphorbia kansui (Euphorbiaceae) on exercise-induced oxidative stress in mice. Exhaustive swimming exercise significantly increases the degree of lipid peroxidation in terms of malondialdehyde content and reduces the antioxidant activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Our findings revealed that chronic oral treatment with the extract elevates enzymatic activities of SOD and GPx accompanied by a corresponding decrease in malondialdehyde. The antioxidative activities of these compounds against exercise-induced oxidative stress are correlated with various activities such as reducing the production of superoxide and hydroxyl radicals, inhibiting lipid peroxidation, enhancing antioxidative defenses, and increasing the production of SOD and GPx activity and expression in different tissues. These compounds may be involved in glycogen metabolism to meet the requirement of working skeletal muscles and act as antioxidants by terminating the chain reaction of lipid peroxidation to maintain the morphological stability of mitochondria in spinal motor neurons. These observations suggest that E. kansui has antioxidative and antifatigue properties and can be given as prophylactic and (or) therapeutic supplements for increasing antioxidant enzyme activities and preventing lipid peroxidation during strenuous exercise.

The role of prostaglandins and the hypothalamus in thermoregulation in the lizard, Phrynocephalus przewalskii (Agamidae).

Typically, small lizards rely heavily on behavioral thermoregulation rather than physiological mechanisms to control their rates of warming and cooling. We tested the hypothesis that prostaglandins participate in mediating the cardiovascular response to heating and cooling and temperature regulating neurons in the hypothalamus of the small lizard Phrynocephalus przewalskii. In vivo and in vitro treatments, heart rates (HRs) were all found to be higher during heating than during cooling, hysteresis was distinct below 30 and 26 degrees Celsius, respectively. In vivo, as administration of COX inhibitor, there were no differences in HR between heating and cooling at any body temperature and administration of agonist prostaglandins only produced a significant effect on HR below 25 degrees Celsius. Single-unit activity was recorded extracellularly in vitro with microelectrodes, found the firing rate of the continuous unit increased 23% when the temperature of the artificial cerebrospinal fluid dropped from 30-20 degrees Celsius. We conclude that prostaglandins appear to play only a limited role in modulating heart activity in Phrynocephalus przewalskii and suggest that cold-sensitive neurons in the preoptic and anterior hypothalamus (PO/AH) are involved in thermoregulatory control during heating or cooling.

Electrocardiogram and heart rate in response to temperature acclimation in three representative vertebrates.

Comparisons of electrocardiogram (ECG) and heart rate characteristics of three representative species in response to temperature acclimation were studied. In toad (Bufo raddei), T wave had positive, negative and flat patterns, which was different from positive in lizard (Eremias multiocellata), blunt and broad in bird (Alectories magna). The duration of P-R interval, Q-T interval and QRS complex interval reduced with increasing temperature in toad, but the P-R and T-P intervals were affected mostly, the QRS and R-T intervals were relatively less affected in lizard. In the bird, the voltage of P, S and T wave scarcely changed, R wave increased slightly with temperature going up in the thermal neutral zone (20-35 degrees C), T and S waves tended to increase and P-S and S-T intervals shortened when temperature went below the neutral zone. Heart rate was high and relatively steady in bird, but changed linearly in relation to temperature in toad and lizard. The increasing of heart rate with temperature was mainly caused by the T-P interval shortened in lizard, but P-S and S-T intervals shortened in bird. Comparisons of ECG and heart rate characteristics of three representative species in response to temperature acclimation reflected phylogenetically based constraints on pacemaker rates, oxygen supply and modulatory mechanisms.

Effects of ambient temperature on lipid and fatty acid composition in the oviparous lizards, Phrynocephalus przewalskii.

This study was designed to assess the effect of ambient temperature on lipid content, lipid classes and fatty acid compositions of heart, liver, muscle and brain in oviparous lizards, Phrynocephalus przewalskii, caught in the desert area of China. Significant differences could be observed in the contents of the total lipid and fatty acid compositions among different temperatures (4, 25 and 38 degrees C). The study showed that liver and muscle were principal sites of lipid storage. Triacylglycerol (TAG) mainly deposited in the liver, while phospholipids (PL) was identified as the predominant lipid class in the muscle and brain. Palmitic and stearic acid generally occupied the higher proportion in saturated fatty acids (SFA), while monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) consisted mainly of 16:1n-7, 18:1n-9, 18:2n-6, 18:3n-3, 20:4n-6 and 22:6n-3 regardless of tissue and temperature. These predominant fatty acids proportion fluctuations caused by temperature affected directly the ratio of unsaturated to saturated fatty acids. There was a tendency to increase the degree of unsaturation in the fatty acids of TAG and PL as environmental temperature dropped from 38 to 4 degrees C, although the different extent in different tissues. These results suggested that lipid characteristics of P. przewalskii tissues examined were influenced by ambient temperature.

Melatonin enhances antinociceptive effects of delta-, but not mu-opioid agonist in mice.

This present study examines the effect of melatonin on antinociceptive action induced by opioid agonists in mice using the tail-flick test. When injected either by intraperitoneal (i.p.) (1, 5, 25 mg/kg) or by intracerebroventricular (i.c.v.) (0.25, 0.5, 1 mg/kg) routes, melatonin significantly enhanced the delta-opioid agonist deltorphin I induced antinociception, but not mu-opioid agonist endomorphin-1. Further investigation showed that i.c.v. luzindole (0.5 mg/kg) (an antagonist of melatonin receptor) significantly antagonized the enhanced antinociceptive effect of i.c.v. melatonin. These results demonstrated that melatonin can specifically enhance the antinociception induced by specific opioid receptor agonist (i.e., delta opioid agonist) acting on melatonin receptor and that melatonin may have augmentation effect on analgesia with delta-, but not mu-opioid agonists in mice.

Isolation and characterization of methyl esters and derivatives from Euphorbia kansui (Euphorbiaceae) and their inhibitory effects on the human SGC-7901 cells.

PURPOSE: In this study, the inhibitory activity of the methyl esters and derivatives extracted from Euphorbia kansui (Euphorbiaceae) and their effect on apoptosis and cell cycle distribution in the human gastric cancer cell line (SGC-7901) were evaluated. METHODS: The inhibitory activity of the methyl esters and derivatives was evaluated by using trypan-blue, MTT (3-(4, 5-dimethyl thiazol-2yl) - 2, 5-diphenyltetrazolium bromide), and FCM (flow cytometry) assays. 5-fluorouracile (5-FU) was used for a positive control. RESULTS: Six new methyl esters and derivatives were extracted from the root of E. kansui. Subjecting the SGC-7901 cell line to the extract indicated that methyl ester derivatives could initiate growth inhibition and induce apoptosis in these tumor cells. The inhibitory rates as measured from trypan-blue and MTT assays were significantly increased and are comparable to those of the common antitumor agent 5-FU. In addition, the methyl ester extract effectively inhibited the proliferation of SGC-7901 cells by interfering with the progression of the cells through the G1 phase of the cell cycle. CONCLUSION: The current study indicates that methyl esters might be a promising chemopreventive and chemotherapeutic agent for treating various forms of cancer by causing apoptosis and proliferation inhibition.

Inhibitory effects of the Gentiana macrophylla (Gentianaceae) extract on rheumatoid arthritis of rats.

Acute treatment of rheumatoid rats with an extract from the roots of Gentiana macrophylla (Gentianaceae) produced a significant inhibitory effect on rheumatoid arthritis (RA). When rats were administered the Gentiana macrophylla extract orally at a daily dose of 100 mg/kg body weight, the prostaglandin E(2) (PGE(2)) levels in the inflammatory tissues, sole thickness, and ankle circumferences of feet were significantly decreased. The anti-inflammatory activity observed in Gentiana macrophylla is comparable to that observed in prednisone. These observations suggest that Gentiana macrophylla displays considerable potency in anti-inflammatory action and could be used as an anti-inflammatory agent in the control of inflammation of rheumatoid arthritis.

Toxic effect of chloromycetin on the ultrastructures of the motor neurons of the Chinese tree shrew (Tupaia belangeri).

This paper describes the toxic effects of chloromycetin on the motor neurons of the Chinese tree shrew (Tupaia belangeri chinensis) with horse radish peroxidase (HRP) as the labeling enzyme. When chloromycetin was administered orally at 2.5 mg/kg (body weight)/day for 3 days, Chinese tree shrews showed evidence of neurotoxicity. This included damage in cortical motor neuron synapses ending on neurons of the red nucleus and the ultrastructural changes in the mitochondria such as swelling of these organelles and blurring of their cristae. There was an increase of the mitochondrial matrix density and of the thickness of the synaptic membranes. These observations indicate that chloromycetin can lead to ultrastructural change of terminals of the cortical motor axons, and that Chinese tree shrews are sensitive animal model for chloromycetin neurotoxicity.

Cloning expression in E.coli and biological activity of human thymosin beta(4).

The cDNA thymosin beta(4) was synthesized by combining of chemical and enzymatic methods. First, two complement fragments of thymosin beta(4) cDNA were synthesized by DNA synthesizer, and then denatured, annealed and extended by DNA polymerase. This fragment of thymosin beta(4) was then inserted into the EcoRV and HindIII restriction endonuclease site of an expression plasmid pLDH4 (a kind of E.coli plasmid) by blunt and cohesive ligations. Finally, the recombinant plasmid which expressed thymosin beta(4) was screened by digestion and DNA sequencing. This recombinant plasmid highly expressed the thymosin beta(4), which accounted for 30% of total bacteria proteins. By salting out and chromatography, a 95% purity of recombinant thymosin beta(4) was obtained. Biological assay indicated that the recombinant thymosin beta(4) could induce lymphocyte proliferation and differentiation.