Visibility of collaboration on the Web

The emerging influence of new information and communication technologies (ICT) on collaboration in science and technology has to be considered. In particular, the question of the extent to which collaboration in science and in technology is visible on the Web needs examining. Thus the purpose of this study is to examine whether broadly similar results would occur if solely Web data was used rather than all available bibliometric co-authorship data. For this purpose a new approach of Web visibility indicators of collaboration is examined. The ensemble of COLLNET members is used to compare co-authorship patterns in traditional bibliometric databases and the network visible on the Web. One of the general empirical results is a high percentage (78%) of all bibliographic multi- authored publications become visible through search of engines in the Web. One of the special studies has shown Web visibility of collaboration is dependent on the type of bibliographic multi-authored papers. The social network analysis (SNA) is applied to comparisons between bibliographic and Web collaboration networks. Structure formation processes in bibliographic and Web networks are studied. The research question posed is to which extent collaboration structures visible in the Web change their shape in the same way as bibliographic collaboration networks over time. A number of special types of changes in bibliographic and Web structures are explained. This revised version was published online in June 2006 with corrections to the Cover Date.     

Interactions of herbicides 2,4-D and dinoseb with liver mitochondrial bioenergetics

The use of drugs for common pregnancy complications like premature labor, hypertensive diseases, and premature rupture of membranes with chorioamnionitis is reviewed. In addition, new publications on antiviral drugs in HIV-positive pregnant patients are also discussed. Among the drugs, suppressing premature labor side-effects of beta-mimetics are of growing concern. The effectiveness of other agents like magnesium, indomethacin, and sulindac are addressed. The various mechanisms explaining the beneficial effect of magnesium in pre-eclampsia are reviewed and new data on antihypertensives, such as labetalol, calcium channel blockers, and methyldopa are presented. The evidence from various clinical trials on the value of low-dose aspirin as a prophylactic agent against pregnancy-induced hypertension, pre-eclampsia, and intrauterine growth retardation in high-risk and low-risk patients is compared. Pharmacokinetic data including transplacental transfer of antibiotics and anti-HIV nucleosides are part of this review.     

The stability of LaNi5 in a Cu matrix

The reaction of LaNi₅ with Cu powder during sintering at high temperature was examined in order to obtain better conductivity and ductility. Pressurized and forged copper-LaNi₅ pellets were investigated by optical metallography, DTA, XRD and TEM. The need for heat treatment after pressing and/or forging is vital to obtain good diffusion bonding between the copper particles and to improve the material strength. No interaction between La, Ni and Cu were observed after heating at 1173 K but a very stable La₂O₃ phase was created around the LaNi₅ particle. Rolling up to 85% reduction showed good ductility.     

Propagation of flicker in electric power networks due to windenergy conversions systems

Wind energy conversion systems (WECS) produce fluctuating output power, which may cause voltage fluctuations and flicker. Flicker assessment in networks may be difficult since its evaluation requires long computing time and special procedures to calculate the flicker severity index, Pst. In this paper, a frequency domain method to study flicker propagation is presented. This method is based on propagation of frequency components from WECS output currents throughout the grid. In this way, a fast flicker analysis in a network of any size can be performed. Also, an algorithm for flicker measurement in the frequency domain, which allows Pst calculation, is proposed. Several study cases have been performed, and results have been compared with time domain simulations, showing good agreement between them     

The molecular biology of bladder carcinoma

OBJECTIVE: The clinical course of transitional cell carcinoma of the bladder can be difficult to predict due to its potential to invade the muscle layer and/or develop to a high grade lesion. Bladder carcinoma can arise from genetic changes that may activate the oncogenes (-c-erbB2, c-erbB1, c-myc, ras, etc.) and/or inactivate the suppressor genes (p53, Rb). The aim of the present study is to continue a study protocol on the molecular biology of bladder tumors. METHODS/RESULTS: From January, 1993 to January, 1995, 85 patients were studied. These patients were divided into two groups: the first group comprised 14 controls of urothelial tissue and the second comprised 65 cases of transitional cell carcinoma of the bladder. p53 expression was determined by an immunohistochemical method (NCL-p53-DO7 monoclonal antibody). Quantification of the p8 oncoprotein in cytosol and EGFR (epidermal growth factor receptor) in membrane was performed by ELISA (Oncogene Science) and RIA (Vienna Lab), respectively. A statistically significant relationship between the expression of p53 and EGFR with tumor stage and grade was found. Quantification of p185 and EGFR showed higher values in the tumor tissue than in the control samples, but a worse survival could not be determined. CONCLUSIONS: The present study shows that p53 expression can be considered to be a prognostic factor. It provides useful information on the aggressive behaviour of the tumor and has a direct relation with the survival rates.     

An Anti-Islanding Method for Single-Phase Inverters Based on a Grid Voltage Sensorless Control

The detection of the islanding condition of a distributed generation (DG) system is crucial for safety reasons, as discussed in the IEEE standards and specifically required by some national codes. Several anti-islanding methods that are resident in the inverter have been investigated and classified as passive (measurement of the natural effects of islanding) or active (based on the measurement of the effects due to transients or harmonics deliberately introduced in the system). In case the power drained by the load matches the power generated by the DG inverter, the effect of islanding is small, and the passive methods fail. However, the active methods, which have been developed to overcome these limits, create disturbances that can interact with those generated by other DG systems. In this paper, a new anti-islanding method is proposed. It exploits the natural sensitivity of a grid-voltage sensorless control to disturbances to highlight the islanding condition. The adopted grid-voltage sensorless control is adapted to a single-phase system with the use of resonant controllers based on the internal model control law: resonant-controller-based observer results. Then, a Kalman-filter-based algorithm is used to detect the islanding condition based on the energy mismatch between the estimated third and fifth harmonics and the real ones. Experimental results support the analysis     

Chromosome-mediated resistance of Yersinia enterocolitica serotype O9 to intracellular killing by mouse peritoneal macrophages

The survival of Yersinia enterocolitica serotype O9 within mouse peritoneal macrophages was investigated. To evaluate the role of the virulence plasmid in the resistance to intracellular killing, an isogenic pair of virulent (plasmid-bearing) and avirulent (plasmid-less) O9 strains was used. The virulent strain was able to express plasmid-encoded outer membrane proteins and to colonize the Peyer's patches of orally infected mice. When mice were infected intraperitoneally, both strains were recovered at similar rates and over the same time from the peritoneal cavity. When in vitro assays were performed, both strains showed similar resistance to intracellular killing by monolayers of resident and inflammatory peritoneal macrophages. Previous opsonization of bacteria did not modify their survival within macrophage monolayers. We concluded that serotype O9 strains display a chromosome-mediated resistance to intracellular killing by mouse peritoneal macrophages. Moreover, macrophage resistance does not seem to be of importance for virulence of serotype O9 strains in mice.     

Olfactory epithelium of the rat. Lectin-mediated histochemical studies

BACKGROUND: Twenty-nine patients with large bulbous and giant aneurysms of the paraclinoid segment of the internal carotid artery (ICA) were operated on, using Dolenc's combined epi- and subdural approach, between 1985 and 1994. Ages ranged from 25 to 79 (83% female; 17% male). METHODS: Proximal control was established in all patients through either an extracranial or petrous carotid exposure. The aneurysm was approached through a wide exposure by removing the anterior clinoid extradural. All but one aneurysm was clipped directly. A saphenous vein graft from the petrous-to-supraclinoid bypass was performed in this remaining case. RESULTS: Surgical morbidity was assessed at 20%. One patient developed a postoperative subdural hematoma and remained severely disabled. Two patients developed permanent third nerve palsy. One patient experienced severe disabling cognitive deficit. One patient died from complications related to a stroke. One patient developed transient diabetes insipidus. Visual outcome, which was assessed separately, was unimproved in 50% of the cases during a follow-up period that averaged 7 years. CONCLUSIONS: With the development of cranial base procedures such as Dolenc's combined epi- and subdural approach, large and giant aneurysms of the paraclinoid segment can be directly clipped with acceptable morbidity, allowing the ICA to remain patent.     

Biosynthesis of unsaturated fatty acids in the diatomPhaeodactylum tricornutum

The biosynthesis of fatty acids in the diatomPhaeodactylum tricornutum was studied. The diatom was incubated with sodium [1¹⁴C] acetate and the acids [1-¹⁴C] palmitic, [1-¹⁴C] stearic, [1-¹⁴C] linoleic and [1-¹⁴C] α-linolenic. The distribution of radioactivity in the products was determined by gas liquid radiochromatography. The diatom synthesized “de novo” not only saturated and monounsaturated fatty acids, but also linoleic, α-linolenic and other fatty acids including the highly polyunsaturated 20∶5ω3 and 22∶6ω3. When labeled acetate, stearic, α-linolenic or even linoleic acid were incubated with the diatom, the polyunsaturated C₂₀ fatty acids synthesized belonged predominantly to the ω 3 family. The existence of Δ9, Δ6, Δ5, Δ4, ω6 and possibly ω3 desaturases inP. tricornutum is suggested. Member of the Carrera del Investigador Científico of the Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Member of the Carrera del Investigador Cientifico of the Consejo Nacional de Investigaciones Cientificas y Técnicas.     

A genetic tango attack against the David–Prasad RFID ultra‐lightweight authentication protocol

Radio frequency identification (RFID) is a powerful technology that enables wireless information storage and control in an economical way. These properties have generated a wide range of applications in different areas. Due to economic and technological constrains, RFID devices are seriously limited, having small or even tiny computational capabilities. This issue is particularly challenging from the security point of view. Security protocols in RFID environments have to deal with strong computational limitations, and classical protocols cannot be used in this context. There have been several attempts to overcome these limitations in the form of new lightweight security protocols designed to be used in very constrained (sometimes called ultra‐lightweight) RFID environments. One of these proposals is the David–Prasad ultra‐lightweight authentication protocol. This protocol was successfully attacked using a cryptanalysis technique named Tango attack. The capacity of the attack depends on a set of boolean approximations. In this paper, we present an enhanced version of the Tango attack, named Genetic Tango attack, that uses Genetic Programming to design those approximations, easing the generation of automatic cryptanalysis and improving its power compared to a manually designed attack. Experimental results are given to illustrate the effectiveness of this new attack.