•New Schiff bases tested as bronze corrosion inhibitors in concentrated acid rain.•2-(Salicylideneimino) thiophenol (SITP) afforded η = 100% after 480 h immersion.•Duplex protective film formed: ...adsorbed SITP molecules over a Cu(I)-SITP layer.•Phosphates (P) added to SITP produced higher resistance against localized attack.•SITP and SITP + P hindered bronze decuprification in concentrated acid rain.
In this research, different Schiff bases were synthesized and tested as bronze corrosion inhibitors in concentrated synthetic acid rain at pH 3.3. Some of them showed good inhibiting effects, as detected by EIS and polarization curve recording. The most efficient inhibitor (2-(salicylideneimino) thiophenol, SITP) was also tested with addition of sodium dihydrogen phosphate (P). P improved the surface film resistance against breakdown phenomena. XPS and SEM investigations showed that SITP and SITP + P significantly hinder decuprification. Moreover, SITP forms a protective layer on bronze, composed of both Cu(I)-SITP complexes and adsorbed inhibitor molecules. Cu(II) phosphates were also detected with P addition.
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•New spontaneous single-crystal growth process of Cs2PbCl2I2 is presented.•Pb substitution is realized on single crystals at 5 % mol. with Bi, In, Ga and Cr.•Single crystal XRD ...analysis show lattice contraction for each substitution.•Photoluminescence peak show a systematic red-shift upon doping.•Blue-shift noticed for Bi doping, attributed to microstrains and radiative states.
Micrometer to millimeter platelets-like single crystals of the 2D-derivated perovskite structure Cs2PbCl2I2 were synthesized by a very simple route using the humid ambient environment surrounding a DMSO solution containing the salt precursors. Cs2Pb1-xMxCl2I2 formation was also evidenced by single crystal X-ray diffraction, with M = Bi, Ga, In and Cr. X-ray photoelectron spectroscopy (XPS) confirmed the presence of each dopant, with an amount of x ∼ 5 ato.% for the last three materials. For the Bi-doped sample, XPS showed a larger quantity of dopant that can be due to XPS difficulty to discriminate too close elements for a few nanometers of analysis or higher concentrations in some crystals due to the affinity of both elements to integrate this structure on the same crystallographic site. A decrease of Bi concentration was determined by ion-beam and XPS simultaneous analysis. Finally, a photoluminescence (PL) peak was observed at ∼420 nm for all samples. Peak widening and blue-shift can be ascribed to the doping, and attributed to photon recycling and radiative self-trapped states. These results show the great versatility of ionic substitution and adaptive optoelectronic properties of the 2D phase that is stable in temperature.
In order to bring the treatment of historical bronze monuments in line with proper engineering practice and cultural heritage regulations, the standardisation of artificially aged surfaces that are ...comparable with natural ones is still to take place. In this aim, this investigation reports a comparative study of corroded quaternary bronze samples produced by accelerated ageing tests, simulating the unsheltered and sheltered exposure conditions mainly affecting outdoor bronze monuments. The effects of run off in a dropping test (unsheltered simulation) and the exposure to stagnant acid rain in a wet & dry test (sheltered simulation) on a bronze surface were studied. A multi-analytical approach was performed including conventional analytical methods, such as a microscopy examination coupled with elemental and structural analyses of the surface. In addition, a focused ion beam (FIB) was used to produce cross-sections in the size range up to a few tens of nanometres. It is evidenced that the corrosion layers, forming a nano-porous structure, are linked to a decuprification process marked by the preferential dissolution of Cu and Zn and the formation of a SnO species network within the barrier layer. A correlation between the tin content of the alloy and the corrosion amplitude is shown: the anodic areas are related to the lowest tin-content part of the alpha phase (in the centre of the dendrite), while the eutectoid areas (including the delta phase) are cathodic and therefore not attacked. The corroded samples artificially aged are well representative of natural corrosion structures observed on outdoor bronzes.
•Two artificial ageing processes well simulate outdoor patinas of as-cast bronze.•Distribution of chemical elements are detailed according to exposure conditions.•-Surface characterization with in situ FIB cross-section highlights decuprification phenomenon.•Alpha (Cu) solid solution is anodic towards (alpha + delta) eutectoid.•Nano-porosities are evidenced within patinas according to corrosion process.
•The potential of the Kanthal Super ER (KSER) for solar applications is evaluated.•KSER is oxidized in muffle or solar furnaces at 1373, 1600, 1850 or 2100 K.•The oxidation in air in temperature ...follows semi-parabolic or subparabolic kinetics.•The radiative properties are not drastically affected by the oxidation.
The oxidation resistance of receivers is a critical point in the development of plants using solar tower technology. Intermetallics in MoSiAl system present oxidation maximum temperature and creep resistance superior to the ones of the currently used Ni-based alloys. We followed here the oxidation resistance of such intermetallic exposed to different treatments in air: long-term oxidation (up to 700 h) at 1373 K, and for several cycles of 20 min in solar furnace. The normal spectral emissivity is measured up to 1640 K in air, and our main positive conclusion is this property is not degraded by the oxidation.
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•Protectiveness of organosilane coating (PropS-SH) on patinated bronze was assessed.•Patina of cuprous oxide and sulphide does not protect the bronze against corrosion.•Both sprayed ...PropS-SH and Incralac® offer a good protection to patinated bronze.•PropS-SH shows excellent performance under UV light and simulated outdoor exposure.•Higher wettability of PropS-SH favours its penetration in porous patina structure.
A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by “liver of sulphur”, was investigated as a non-toxic alternative to Incralac®, usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and accelerated corrosion test simulating unsheltered exposure to rainwater was also carried out. The exposed samples were characterised by FEG-SEM coupled with EDS on FIB cross-sections and XPS on free surfaces. The black patina without protective coating was scarcely protective against bronze corrosion and easily transformed into cuprous oxide. PropS-SH coating fully preserved the black patina microstructure and phase constituents (cuprous oxide and cuprous sulphide). The PropS-SH coating also resulted more protective than Incralac® when aged under run-off conditions. Selective dissolution of copper from the silicon bronze alloy was observed on both uncoated and Incralac®-coated bronze, leading to the formation of an internal Si-rich corrosion layer.
•Fire-gilded bronze prepared by ancient methods (Au–Hg layer on Cu–Sn–Zn–Pb–Sb).•Heating during gilding induces Sn and Znenrichment in the top part of the gilded layer.•SR-HRPES mapping of corrosion ...craters (cross-section) after accelerated ageing.•Selective dissolution of Cu and Zn in the craters induces Sn species enrichment.•The main species in the craters are related to hydroxi-oxide compounds.
Gilded bronzes are often affected by severe corrosion, due to defects in the Au layer and Au/Cu alloy galvanic coupling, stimulated by large cathodic area of the gilded layer. Galvanic corrosion, triggered by gilding defects, leads to products growth at the Au/bronze interface, inducing blistering or break-up of the Au layer. In this context, fire-gilded bronze replicas prepared by ancient methods (use of spreadable Au–Hg paste) was specifically characterised by compiling complementary spectroscopic and imaging information before/after accelerated ageing with synthetic rain. Fire-gilded bronze samples were chemically imaged in cross-section at nano-metric scale (<200nm) using high energy and lateral resolution synchrotron radiation photoemission (HR-SRPES) of core levels and valence band after conventional characterisation of the samples by Glow Discharge optical Emission Spectroscopy (GD-OES) and conventional X-ray photoelectron spectroscopy (XPS). We have found a net surface enrichment in Zn and Sn after fire-gilding and presence of metallic Hg, Pb and Cu within the Au layer. Moreover, the composition distribution of the elements together with their oxidation has been determined. It was also revealed that metallic phases including Hg and Pb remain in the gilding after corrosion. Moreover, selective dissolution of Zn and Cu occurs in the crater due to galvanic coupling, which locally induces relative Sn species enrichment (decuprification). The feasibility advantages and disadvantages of chemical imaging using HR-SRPES to study artworks have been investigated on representative replicas.
Serine-threonine protein kinases of the DYRK and CLK families regulate a variety of vital cellular functions. In particular, these enzymes phosphorylate proteins involved in pre-mRNA splicing. ...Targeting splicing with pharmacological DYRK/CLK inhibitors emerged as a promising anticancer strategy. Investigation of the pyrido3,4-
quinazoline scaffold led to the discovery of DYRK/CLK binders with differential potency against individual enzyme isoforms. Exploring the structure-activity relationship within this chemotype, we demonstrated that two structurally close compounds, pyrido3,4-
quinazoline-2,10-diamine
and 10-nitro pyrido3,4-
quinazoline-2-amine
, differentially inhibited DYRK1-4 and CLK1-3 protein kinases in vitro. Unlike compound
, compound
efficiently inhibited DYRK3 and CLK4 isoenzymes at nanomolar concentrations. Quantum chemical calculations, docking and molecular dynamic simulations of complexes of
and
with DYRK3 and CLK4 identified a dramatic difference in electron donor-acceptor properties critical for preferential interaction of
with these targets. Subsequent transcriptome and proteome analyses of patient-derived glioblastoma (GBM) neurospheres treated with
revealed that this compound impaired CLK4 interactions with spliceosomal proteins, thereby altering RNA splicing. Importantly,
affected the genes that perform critical functions for cancer cells including DNA damage response, p53 signaling and transcription. Altogether, these results provide a mechanistic basis for the therapeutic efficacy of
previously demonstrated in in vivo GBM models.
This review, of the literature published between 2010 and 2015 reports that molecules containing a non-fused and/or fused pyrazole moiety could exhibit very potent activity toward Pim kinases, ...including the inhibition of cellular Bad phosphorylation as well as antiproliferative activity against various cancer cells. Even if Pim kinase inhibitors currently in clinical trial do not exhibit a pyrazole moiety, heteroaromatic kinase inhibitors containing an indazole part such as Axitinib and Pazopanib already reached the market. Therefore, one can imagine that in the future, heteroaromatic derivatives inhibiting Pim kinases including pyrazoles could be identified and used for their diagnostic and/or therapeutic potential alone or in combination with other drugs for the diseases in which Pim kinases are involved.
The development of efficient copper deposition processes in high-aspect-ratio silicon structures is still a key technological issue for the microelectronic industry. We describe here a new process ...for the deposition of copper thin films in three-dimensional (3D) structures induced by the decomposition of a copper amidinate precursor in solution under a moderate H2 pressure. The reduction of a metal precursor under soft conditions (3 bar, 110 °C) affords the preparation of a high-purity, conformal metallic layer. We unveil a novel deposition mechanism driven by colloidal copper nanoparticles (NPs) in solution that behave as a reservoir of metastable metallic NPs that eventually condense as a solid film on all immersed surfaces. The film growth process is characterized by time-resolved analyses of the NPs in the colloidal state (nuclear magnetic resonance NMR and UV–vis spectra) and of the NPs and metallic layer on substrates (transmission electron microscopy TEM, and scanning electron microscopy SEM). Major deposition stages of this process are proposed and the conformal metallization of 3D silicon substrates is successfully achieved. This method is transposable to other metallic layers such as silver or nickel.
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