835 research outputs found

    EFFECT OF SULFACETAMIDE ON THE COMPOSITION OF CORROSION PRODUCTS FORMED ONTO CARBON STEEL SURFACE IN HYDROCHLORIC ACID

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    IUPAC name N- [(4-aminophenyl) sulfonyl] acetamide (APSA) on the corrosion of carbon steel in 1.0 M HCl solution has been investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and XPS analysis. The electrochemical measurements indicated that the presence of APSA in 1.0 M HCl solution decreases the corrosion current (i corr ) and increases the polarization rezistance (R p ). XPS surface analysis showed at this stage, in the absence of APSA, that the main product of corrosion is a non-stoichiometric Fe 3+ oxide/oxidehydroxide, consisting of a mixture of Fe 2 O 3 and FeO(OH), where FeO(OH) is the main phase. Moreover, in presence of inhibitor the surface layer consists of FeO(OH) rather than pure oxide, adsorbed molecules of sulfacetamide and inorganic compounds such as: sulfides, carbonates, sulphates, nitrates, which were obtained by electrochemical degradation of APSA. UV-Vis spectrophotometry and HPLC technique were performed to determine the medium composition before and after corrosion. The results showed a decrease of the inhibitor concentration in 1.0 M HCl solution after carbon steel corrosion, indicating an adsorption process between organic compound molecules from aqueous phase and the electrode surface and/or the electrochemical degradation of APSA

    To be or not to be a neurovascular conflict: importance of the preoperative identification of the neurovascular conflict in the trigeminal neuralgia

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    The trigeminal neuralgia caused by neurovascular compression is a neurosurgical pathology requiring the preoperative identification as exact as possible of the neurovascular conflict. In this case, neuroimaging is very useful, as it allows not only the determination of the neurovascular conflict of the trigeminal nerve, but also the correct indication of an adequate surgical approach

    A rare case of suprasellar arachnoid cyst with giant perimesencephalic and mesial temporal extension - physiopathological mechanisms

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    The arachnoid cyst is a lesion commonly encountered in neurosurgery, especially in pediatric pathology. We are presenting the case of an adult patient with a suprasellar arachnoid cyst with giant perimesencephalic and mesial temporal extension discovered incidentally, where there is a discrepancy between the spectacular neuroimaging and the non-specific symptomatology. Some of the physiopathological mechanisms which led to the evolution of the cyst will also be presented

    Pathways of metastatic spread in meningiomas

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    Meningioma is a common intracranial neoplasm derived from meningothelial cells, and it is generally associated with a benign clinical course. In spite of this, the malignant behaviour of these tumours as the occurrence of extracranial meningioma metastases in different organs is described in the literature: lung and pleura, spine and other bones, abdominal organs, lymph nodes or even skin. The aim of this review is to analyse the pathways of metastatic spread of the intracranial meningioma tumour cells towards different organs

    Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays

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    Average charged multiplicities have been measured separately in bb, cc and light quark (u,d,su,d,s) events from Z0Z^0 decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of bb and light quark events, and reconstructed charmed mesons were used to select cc quark events. We measured the charged multiplicities: nˉuds=20.21±0.10(stat.)±0.22(syst.)\bar{n}_{uds} = 20.21 \pm 0.10 (\rm{stat.})\pm 0.22(\rm{syst.}), nˉc=21.28±0.46(stat.)−0.36+0.41(syst.)\bar{n}_{c} = 21.28 \pm 0.46(\rm{stat.}) ^{+0.41}_{-0.36}(\rm{syst.}) nˉb=23.14±0.10(stat.)−0.37+0.38(syst.)\bar{n}_{b} = 23.14 \pm 0.10(\rm{stat.}) ^{+0.38}_{-0.37}(\rm{syst.}), from which we derived the differences between the total average charged multiplicities of cc or bb quark events and light quark events: Δnˉc=1.07±0.47(stat.)−0.30+0.36(syst.)\Delta \bar{n}_c = 1.07 \pm 0.47(\rm{stat.})^{+0.36}_{-0.30}(\rm{syst.}) and Δnˉb=2.93±0.14(stat.)−0.29+0.30(syst.)\Delta \bar{n}_b = 2.93 \pm 0.14(\rm{stat.})^{+0.30}_{-0.29}(\rm{syst.}). We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
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