166 research outputs found

    On the Corrosion Resistance of Porous Electroplated Zinc Coatings in Different Corrosive Media

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    The corrosion resistance of an electroplated (EP) Zn coating whose surface was chemically etched to produce surface defects (pores) is investigated in this work. Impedance and DC polarisation measururements were employed to study the behaviour of such coating in various corrosive media (NaCl, NaOH and rain water). Four different faradaic relaxation processes were clearly revealed in different NaCl concentrations (from 0.1M to 1M). In the most concentrated solutions at least three relaxation processes at low frequencies (LF) appeared and were related to zinc deposition and dissolution. At lower concentrations and depending on the pH, only one process was observed. The charge transfer resistance (Rct) and the corrosion current (Icorr) were practically stable in the pH range 5 to 10. In deaerated NaCl 0.1M, the EIS diagrams showed two time-constants at very close frequencies. From the EIS diagrams the porous nature of the coating was highlighted and showed that the dissolution mechanisms occurred at the base of the pores

    Liefde voor het Openbaar Bestuur en Liefde voor de Bestuurskunde

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    Arthur Ringeling heeft in zijn afscheidsrede van 28 september 2007 aan de Erasmus Universiteit Rotterdam een terugblik gegeven op de langdurige studiereis die hij op het vakgebied der bestuurskunde heeft afgelegd. Zijn academische studiereis in de bestuurskunde nam een aanvang met zijn studie politicologie aan de Vrije Universiteit van Amsterdam, welke hij in 1969 afrondde. Daarna verhuisde de protestantse Amsterdammer naar het katholieke Zuiden om aan de katholieke Universiteit van Nijmegen wetenschappelijk medewerker te worden en in 1978 met succes een proefschrift te verdedigen over ‘beleidsvrijheid van ambtenaren’. In 1981 werd hij benoemd tot hoogleraar aan de Erasmus Universiteit Rotterdam, waar hij in 1983 zijn oratie uitsprak met de titel ‘De Instrumenten van het Beleid’. In 1987 was hij betrokken bij het onderzoek van de parlementaire enquêtecommissie rond de paspoortaffaire. In 1992 verbleef hij een ‘sabbatical year’ op de School of Public and Environmental Affairs (SPEA) aan de Indiana University te Bloomington. In 1993 publiceerde hij zijn bekende boek ‘Het imago van de overheid’. En zoals we hierna zullen zien, ondernam hij daarna nog allerlei activiteiten die hem tot een bestuurskundige maakten die zowel in de wetenschap als de praktijk van het Nederlandse openbaar bestuur naam en faam heeft gemaakt

    4-Deoxyphorbol inhibits HIV-1 infection in synergism with antiretroviral drugs and reactivates viral reservoirs through PKC/MEK activation synergizing with vorinostat.

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    Latent HIV reservoirs are the main obstacle to eradicate HIV infection. One strategy proposes to eliminate these viral reservoirs by pharmacologically reactivating the latently infected T cells. We show here that a 4-deoxyphorbol ester derivative isolated from Euphorbia amygdaloides ssp. semiperfoliata, 4β-dPE A, reactivates HIV-1 from latency and could potentially contribute to decrease the viral reservoir. 4β-dPE A shows two effects in the HIV replication cycle, infection inhibition and HIV transactivation, similarly to other phorboids PKC agonists such PMA and prostratin and to other diterpene esters such SJ23B. Our data suggest 4β-dPE A is non-tumorigenic, unlike the related compound PMA. As the compounds are highly similar, the lack of tumorigenicity by 4β-dPE A could be due to the lack of a long side lipophilic chain that is present in PMA. 4β-dPE activates HIV transcription at nanomolar concentrations, lower than the concentration needed by other latency reversing agents (LRAs) such as prostratin and similar to bryostatin. PKCθ/MEK activation is required for the transcriptional activity, and thus, anti-latency activity of 4β-dPE A. However, CD4, CXCR4 and CCR5 receptors down-regulation effect seems to be independent of PCK/MEK, suggesting the existence of at least two different targets for 4β-dPE A. Furthermore, NF-κb transcription factor is involved in 4β-dPE HIV reactivation, as previously shown for other PKCs agonists. We also studied the effects of 4β-dPE A in combination with other LRAs. When 4β-dPE A was combined with another PKC agonists such as prostratin an antagonic effect was achieved, while, when combined with an HDAC inhibitor such as vorinostat, a strong synergistic effect was obtained. Interestingly, the latency reversing effect of the combination was synergistically diminishing the EC50 value but also increasing the efficacy showed by the drugs alone. In addition, combinations of 4β-dPE A with antiretroviral drugs as CCR5 antagonist, NRTIs, NNRTIs and PIs, showed a consistent synergistic effect, suggesting that the combination would not interefer with antiretroviral therapy (ART). Finally, 4β-dPE A induced latent HIV reactivation in CD4 + T cells of infected patients under ART at similar levels than the tumorigenic phorbol derivative PMA, showing a clear reactivation effect. In summary, we describe here the mechanism of action of a new potent deoxyphorbol derivative as a latency reversing agent candidate to decrease the size of HIV reservoirs.This work was supported by Ministry of Education of the Peruvian government (PRONABEC), the Universidad Complutense de Madrid (UCM-Santander PR87/19), the Instituto de Salud Carlos III (ISCIII-FIS PI16CIII/00034) and the Spanish AIDS Research Network RD12/0017/0015 that is included in the Spanish I D I Plan and is co-financed by ISCIII-Subdirección General de Evaluación and European Funding for Regional Development (FEDER). This work has also benefited from an “Investissement d’Avenir” grant managed by Agence Nationale de la Recherche (CEBA, ANR- 10-LABX-25-01).S

    Politiebestel in balans? Politiek-bestuurlijke sturing, democratische verantwoording, samenwerking en maatschappelijke inbedding in een nationaal politiebestel

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    Op 1 januari 2013 trad de Politiewet 2012 in werking. Artikel 74 van de wet bepaalt dat de Minister van Justitie en Veiligheid binnen vijf jaar na inwerkingtreding een evaluatie van die wet aan de Staten-Generaal moet sturen over doeltreffendheid en effecten van de wet in de praktijk.In dit rapport staat de vraag centraal hoe de Politiewet 2012 in de praktijk is geïmplementeerd en welke consequenties zich voordoen voor de politieorganisatie en voor de verschillende externe partijen die bij het politiewerk betrokken zijn. De hoofdvraag die aan dit onderzoek ten grondslag ligt, luidt: Hoe kan de werking van de Politiewet 2012 inzake de thema’s (1) politiek bestuurlijke sturing en politiek-democratische verantwoording, (2) samenwerking en (3) maatschappelijke inbedding, worden geëvalueerd?Security and Global Affair

    Mind the implementation gap?:Police reform and local policing in the Netherlands and Scotland

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    In 2013 the governments of the Netherlands and Scotland established national police forces, replacing a tradition of largely autonomous regional police organizations. In both jurisdictions, these radical reforms have raised concerns about the consequences of these national police structures for local policing and for relationships with local communities and local government. Drawing on documentary sources and interview material from each jurisdiction and informed by insights from the policy implementation literature, the key question addressed in this article is how has the legislation that created the new national police forces been put into effect at a local level? Focusing on the impact on the governance, organization and delivery of local policing, the article reveals how the implementation in both jurisdictions involves interpretation and discretion by multiple actors so that gaps are emerging between the national ‘policy promises’ set out in the legislation and the ‘policy products’ experienced in local contexts

    The interaction between the proliferating macroalga Asparagopsis taxiformis and the coral Astroides calycularis induces changes in microbiome and metabolomic fingerprints

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    Mediterranean Sea ecosystems are considered as hotspots of biological introductions, exposed to possible negative effects of non-indigenous species. In such temperate marine ecosystems, macroalgae may be dominant, with a great percentage of their diversity represented by introduced species. Their interaction with temperate indigenous benthic organisms have been poorly investigated. To provide new insights, we performed an experimental study on the interaction between the introduced proliferative red alga Asparagopsis taxiformis and the indigenous Mediterranean coral Astroides calycularis. The biological response measurements included meta-barcoding of the associated microbial communities and metabolomic fingerprinting of both species. Significant changes were detected among both associated microbial communities, the interspecific differences decreasing with stronger host interaction. No short term effects of the macroalga on the coral health, neither on its polyp activity or its metabolism, were detected. In contrast, the contact interaction with the coral induced a change in the macroalgal metabolomic fingerprint with a significant increase of its bioactivity against the marine bacteria Aliivibrio fischeri. This induction was related to the expression of bioactive metabolites located on the macroalgal surface, a phenomenon which might represent an immediate defensive response of the macroalga or an allelopathic offense against coral.ERA-NET Biome project "SEAPROLIF"; CNRS; Provence Alpes Cote d'Azur Region; TOTAL Fundation; Fundacao para a Ciencia e a Tecnologia (FCT) [Netbiome/0002/2011]; FCT fellowships [SFRH/BPD/63703/2009, SFRH/BPD/107878/2015]info:eu-repo/semantics/publishedVersio
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