Link Prediction based on Structural Properties of Online Social Networks

Question-Answering Bulletin Boards (QABB), such as Yahoo! Answers and Windows Live QnA, are gaining popularity recently. Questions are submitted on QABB and let somebody in the internet answer them. Communications on QABB connect users, and the overall connections can be regarded as a social network. If the evolution of social networks can be predicted, it is quite useful for encouraging communications among users. Link prediction on QABB can be used for recommendation to potential answerers. Previous approaches for link prediction based on structural properties do not take weights of links into account. This paper describes an improved method for predicting links based on weighted proximity measures of social networks. The method is based on an assumption that proximities between nodes can be estimated better by using both graph proximity measures and the weights of existing links in a social network. In order to show the effectiveness of our method, the data of Yahoo! Chiebukuro (Japanese Yahoo! Answers) are used for our experiments. The results show that our method outperforms previous approaches, especially when target social networks are sufficiently dense.

Process development for industrial-scale preparation of carboxypeptidase Y secreted by Saccharomyces cerevisiae

A method for industrial-scale preparation of carboxypeptidase Y (CPY), which was secreted by Saccharomyces cerevisiae KS58-2D/pCY303 into the culture broth, was developed. Because the purification process consists of a few simple unit operations including only one chromatography step, a higher CPY recovery was achieved than that in the process using disrupted baker's yeast. Approximately 100 g of purified CPY powder was constantly obtained using the final culture broth from a 500-l fermentor.     

Chlorination and carbochlorination of magnesium oxide

Thermogravimetric technique and boat experiments were used to study the chlorination of MgO and its reactivity with respect to Cl₂ + air, Cl₂ + N₂, and Cl₂ + CO gas mixtures at temperatures lower than 1000°C. Oxychlorination of MgO occurs at temperatures higher than that of its carbochlorination. Effects of experimental parameters such as gas flow rate, temperature, and partial pressure of the carbochlorinating gas mixture on the reaction rate were examined. At 550 °C, the apparent reaction orders with respect to Cl₂ + CO, Cl₂, and CO were 2.37, 1.47, and 0.89, respectively. At this temperature, the maximum reaction rate was obtained using a Cl₂ + CO gas mixture having a Cl₂/CO molar ratio equal to about 0.6. The apparent activation energy of carbochlorination of MgO was calculated as 49 kJ/mol between 425 °C and 600 °C.     

Recycling ferrous sulfate via super-oxidant synthesis

Hydrated ferrous sulfate, a by-product of the titanium-dioxide and steel-surface-treatment industries, is usually disposed of as waste at a significant extra cost for these industries. Due to tight environmental regulations in the European countries, waste disposal of ferrous sulfate will not be an acceptable solution in the near future. Consequently, the waste will have to be treated. Recently, ferrous sulfate was successfully used to synthesize a novel superoxidant material (potassium ferrate) containing iron in hexavalent state (Fe^VI). With ferrates synthesis, innovative applications are possible in different industrial sectors, such as treatment of water and wastewater and effluent decontamination. For more information, contact N. Kanari, Laboratoire Environnement et Minéralurgie (LEM), Mineral Processing and Environmental Engineering team, BP 40, 54501 Vandœuvre, France.     

A bioassay for serum interferon based on induction of 2''5''-oligoadenylate synthetase activity

BACKGROUND: Patients treated for primary hyperparathyroidism run an increased risk of death. The aim of this study was to analyse several factors that may influence their risk of death. METHODS: General, laboratory, physical and clinical variables, altogether 34 variables, were defined as possible risk factors for death and were studied in a patient series of 845 patients operated on during the period 1953-82. Mean follow-up time was 10.5 years (SD 5.9); 253 patients were deceased at follow-up. Cox's proportional hazard model was used. RESULTS: We found seven variables with independent influence on the risk of death: age, sex, diabetes, cardiovascular disease, glomerular filtration rate, renal tubular concentration capacity and amount of diseased parathyroid tissue. The remaining 27 variables were separately tested, one at a time, using the same method and with the influence of age and sex eliminated. In this test situation, the year of surgery, peak serum calcium, serum creatinine level, body mass index, hypertension, psychiatric symptoms and a history of crisis were all significantly related to the risk of death. The analyses also gave information on the direction and magnitude of the effect of the variables on the risk of death. CONCLUSION: Primary hyperparathyroidism itself is a risk factor for death, but it was concluded that well-preserved renal function at surgery seems to have a protective role. We also found that the greater the amount of diseased parathyroid tissue the lesser the renal function and, furthermore, that hyperparathyroidism of substantial degree or long duration may bring about renal impairment that is not necessarily disclosed by the creatinine value alone.     

Selective MR angiography of the liver

OBJECTIVE: Two-dimensional time-of-flight MR angiography was done with a 1.0 T whole-body imaging system. METHODS: The 10 mm thick presaturation slab was positioned between two sagittal imaging slices of the liver. Images were obtained through the right lobe of the liver by moving the slab and slices together. Each image was acquired during a breath-holding interval of 16 s. RESULTS: Since the directions of the portal and hepatic venous flows are opposite to each other in the right lobe, these two venous systems could be visualized on separate images by the interleaved presaturation slab. On the reconstructed angiograms, separation between the two venous systems was complete and even the fourth and fifth branches were demonstrated clearly. These images facilitate clear understanding of the structure of the intrahepatic blood vessels. CONCLUSION: Although this technique is limited to volunteer studies and works only on the right lobe of the liver, it will provide valuable information for evaluating the location and vascular involvement in various liver diseases.     

Boron determination in a multi element national water monitoring program: the absence of legal limits

Directive 98/83/EC concerning the drinking water quality and Directive 80/777/EC for Natural Mineral Water demand strict control and monitoring for the presence of metals. The State General Laboratory as the official control laboratory (Accredited by ISO 17025:2005) implements a national monitoring program in order to ensure that the drinking and natural mineral water quality satisfy the requirements of the respective Directives. The National Monitoring program covers mainly metals such as Pb, Cd, Cr, Ni, As, Se, Sb, Hg, Mn, Cu, Fe, Al and B in water supplied for human consumption either by distribution networks, vending machines, mobile water containers, ground water intended for human consumption as well as bottled water. The determination of metals in water by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) is a technique that successfully meets the requirements of the above Directives as it is a very powerful tool for the measurement of metals at very low concentrations with high accuracy and precision. The results obtained indicate that metal concentrations in drinking and bottled water examined were by far, below the acceptable legal limits and even below the relevant detection limits. However, in samples of bottled natural mineral water, high boron concentration were determined and risk assessment was performed due to the absence of relevant legal limits. The present paper demonstrates the steps undertaken by the General Water Analysis Laboratory of the SGL for the validated method used by ICP-MS in the determination of trace metals including boron in drinking and bottled water.     

Excess estrogen sulfoconjugation as the possible cause for a poor sign of parturition in pregnant cows carrying somatic cell clone fetuses

We conducted this study to elucidate a factor causing a poor sign of parturition and prolonged gestation, which is frequently observed in cows carrying somatic clone fetuses. Pre-partum rises in concentrations of plasma estrone and estradiol-17beta in the recipient cows pregnant with clones were subtle. By contrast, the plasma concentration of estrone sulfate in clone pregnancies increased gradually from pre-initiation of parturition induction whereas control cows that received in vivo-derived embryos showed a significant increase at parturition. Therefore, in clone pregnancies, the ratio of estrone/estrone sulfate was low during the pre-partum period compared with control. Messenger RNA expression of estrogen sulfotransferase (SULT1E1) in the placenta at parturition was significantly higher in clone pregnancies than control pregnancies and was localized in binucleate cells (BNC). SULT1E1 mRNA abundance was negatively and positively correlated with concentrations of maternal estrone and estrone sulfate at parturition respectively. Messenger RNA expressions of estrogen sulfatase (STS) and aromatase (CYP19) were similar between clone and control pregnancies and were localized in BNC and caruncular epithelial cells. STS and CYP19 mRNA abundances showed positive correlations with maternal estradiol-17beta concentration. The population of BNC in the placenta did not differ between clone and control pregnancies. Plasma cortisol concentration of vaginally delivered newborn clone calves was comparable with those of control, although cesarean section delivered clone calves showed a low concentration. These results suggest that excess estrogen sulfoconjugation is the reason for the perturbed low ratio of active to inactive estrogens and the resulting hormonal imbalance contributes to the lack of overt signs of readiness for parturition in cows pregnant with clones.