Study of the development of thermoresistance in human pancreatic carcinoma cell lines using proteome analysis

In order to find candidate proteins that are potentially associated with the thermoresistant phenotype in combination with drug resistance, we analyzed the differential protein expression in vitro in the human pancreatic cancer cell line EPP85-181-P and classical and atypical multidrug-resistant variants and their thermoresistant counterparts using proteomics. This study identifies sets of proteins that may lead to the development of thermoresistance. These results provide a fundamental basis to elucidate the molecular mechanism of thermoresistance and chemoresistance phenomena that may assist the therapy of inoperable cancers.     

Metal Oxoclusters as Molecular Building Blocks for the Development of Nanostructured Inorganic–Organic Hybrid Thin Films

Silica-based inorganic–organic hybrid thin films embedding the organically modified oxohafnium clusters (Hf₄O₂(OMc)₁₂, OMc=OC(O)–C(CH₃)=CH₂) were obtained by photo-activated free radical copolymerisation of the methacrylate groups of the cluster with those of the pre-hydrolysed (methacryloxypropyl)trimethoxysilane (MAPTMS, (CH₂=C(CH₃)C(O)O)(CH₂)₃Si(OCH₃)₃). By this route, a covalent anchoring of the cluster to the forming silica network was achieved. Samples characterized by two different Si/Hf compositions (18:1, 5:1) were prepared. The surface and in-depth composition of the thin films were investigated through Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). XPS depth profiles performed on the thin layers evidenced a homogenous in depth distribution of the hafnium guest species within the whole silica films and sharp film-substrate interfaces. Broad band dielectric spectroscopy (BDS) measurements permitted to investigate the electric response of the obtained films in the frequency and temperature range of 40 Hz – 1 MHz and 0–160°C.     

DNA-templated assembly of nanoscale wires and protein-functionalized nanogap contacts

The use of DNA to template the assembly of nanoscale wires and protein-functionalized nanogap contacts is described: Specifically, the use of DNA to template the assembly of gold nanowires between conventionally patterned gold contacts on a silicon wafer substrate. Also described is the use of DNA to template the assembly of protein-functionalized nanogap gold contacts on a silicon wafer substrate. Of particular significance is the finding that suitably modified gold nanoparticles recognize and bind selectively the protein-functionalized nanogap and are localized there.     

Three-dimensional self-assembly of metallic rods with submicron diameters using magnetic interactions

Metallic rods with submicron diameters that contain disklike ferromagnetic sections self-assemble into highly stable, hexagonally close-packed arrays of rods. The rods were fabricated by electrodeposition in porous alumina membranes and comprised alternating sections of gold and nickel. The thicknesses of the ferromagnetic nickel sections were approximately one-half the diameter of the rods (400 nm); this geometry orients the "easy" axis of magnetization perpendicular to the long axis of the rod. After magnetization of the rods with a rare-earth magnet, followed by sonication of the suspension, the rods spontaneously assembled into three-dimensional (3D) bundles that, on average, contained 15-30 rods. A macroscopic model of the rods suggests that the most stable orientation of the magnetic dipoles for rods in a defect-free, hexagonally close-packed arrangement is in concentric rings with the dipoles oriented head-to-tail. This configuration minimizes the energy of the bundle and does not generate a net dipole for the structure. This work provides a simple demonstration that magnetic interactions between ferromagnetic objects can direct and stabilize the formation of ordered, 3D structures by self-assembly.     

Solid-state photodimerization of steroid enones

Androst-4-ene-3,17-dione (1) and 17alpha-methyltestosterone (2) are dimerized in the solid-state by UV radiation. These substances were selected by a search in the CSD among the steroid enones presenting in the crystalline state an intermolecular short contact between a hydrogen alpha to a carbonyl group and the oxygen of an enone system. Dimerization occurs by transfer of the hydrogen to the oxygen and connection between the two involved carbons. Androst-4-ene-3,17-dione (1) affords dimer 3 and trimer 4, both formed by connection of the C-16 of a molecule with the C-3 of a near one. Irradiation of 17alpha-methyltestosterone (2) gives the isomeric trienones 5 and 6. These compounds are reasonably formed by dehydration of unisolated intermediate products 7 and/or 8 obtained by coupling of two molecules through a linkage between the C-2 and the C-3' carbons. The formation mechanisms of the photoproducts are satisfactory explained on the basis of the molecular arrangement of the monomers in the crystal state. Modeling of the dimeric molecules was done using molecular mechanics calculations. A single-crystal X-ray of the dimer of androst-4-ene-3,17-dione confirms the structural interpretation of spectral data. The conformer found in the solid-state agrees well with the results of molecular mechanics calculations.     

Multiple nitrene insertions into metal-sulfur bonds of dithiocarbamate complexes: synthesis of sulfido-amido and zwitterionic tetraamido complexes

The iodine(III) reagent, PhI[double bond, length as m-dash]NTs, acts as a source of the nitrene fragment NTs, which undergoes facile insertion into the metal-sulfur bonds of a range of dithiocarbamate complexes. Addition of two equivalents of PhI=NTs to [M(S(2)CNR2)2] affords sulfido-amido complexes [M{SC(NR2)SNTs}2](M=Ni, Cu), which insert two further nitrene fragments to afford zwitterionic tetraamido complexes [M{TsNSC(NR2)SNTs}2](M=Co, Ni, Cu). Crystallographic studies have been carried out on both types of complex allowing possible resonance hydrids of the new ligand types to be assessed.     

Experimental and theoretical study of the interaction of CO2 with alpha-Al2O3

Density functional molecular cluster calculations are combined with X-ray photoelectron spectroscopy (XPS), quadrupolar mass spectrometry (QMS), and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy to investigate the interaction of CO2 with alpha-Al2O3 and partially reduced alpha-Al2O3. The electronic structure of the stoichiometric and partially reduced substrate, adsorbate geometries, chemisorption enthalpies, and adsorbate vibrational parameters are computed and discussed. Theoretical results agree quite well with experimental data and previous theoretical investigations. As far as the adsorbate-substrate interaction is concerned, the results of our calculations indicate that CO2 forms bidentate-chelating carbonate species. The bonding scheme of this surface complex implies a significant substrate-->adsorbate transfer of charge (from the occupied dangling bond of a surface Lewis base site into one component of the CO2 2 pi u LUMO) assisted by a definitely weaker adsorbate-->substrate donation (from one component of the CO2 1 pi g HOMO into an empty dangling bond of a surface Lewis acid site). Our estimate of the chemisorption enthalpy (-15 kcal/mol) agrees quantitatively with calorimetric data reported for CO2 adsorbed on high surface area alpha-alumina (-16.0 kcal/mol). [Mao, C.-F.; Vannice, M. A. Appl. Catal. A 1994, 111, 151.] According to XPS and QMS outcomes, theoretical results predict that the interaction of CO2 with partially reduced alpha-Al2O3 gives rise to the reduction of the adsorbate to CO and to the concomitant substrate reoxidation.     

Biologisch aktive 3,3-Dimethylbicyclo[2.2.2]octane: Synthesen in der Isocamphanreihe, 35. Mitt.

Summary The bicyclo[2.2.1]- and [2.2.2]-systems are part of numerous biological active substances. Continuing our syntheses in the isocamphane series the homologous isocamphanes of mecamylamine (1 a) and of the fungicidal bicyclic compound2 were synthesized. Furthermore the syntheses ofE-homoisosantalene (15) andE,E-homoisosantalol (16) are described.

     

Progress,highlights and perspectives on NiO in perovskite photovoltaics

The power conversion efficiency (PCE) of NiO based perovskite solar cells has recently hit a record 22.1% with a hybrid organic–inorganic perovskite composition and a PCE above 15% in a fully inorganic configuration was achieved. Moreover, NiO processing is a mature technology, with different industrially attractive processes demonstrated in the last few years. These considerations, along with the excellent stabilities reported, clearly point towards NiO as the most efficient inorganic hole selective layer for lead halide perovskite photovoltaics, which is the topic of this review. NiO optoelectronics is discussed by analysing the different doping mechanisms, with a focus on the case of alkaline and transition metal cation dopants. Doping allows tuning the conductivity and the energy levels of NiO, improving the overall performance and adapting the material to a variety of perovskite compositions. Furthermore, we summarise the main investigations on the NiO/perovskite interface stability. In fact, the surface of NiO is commonly oxidised and reactive with perovskite, also under the effect of light, thermal and electrical stress. Interface engineering strategies should be considered aiming at long term stability and the highest efficiency. Finally, we present the main achievements in flexible, fully printed and lead-free perovskite photovoltaics which employ NiO as a layer and provide our perspective to accelerate the improvement of these technologies. Overall, we show that adequately doped and passivated NiO might be an ideal hole selective layer in every possible application of perovskite solar cells.

The power conversion efficiency of NiO based perovskite solar cells has recently hit a record 22.1%. Here, the main advances are reviewed and the role of NiO in the next breakthroughs is discussed.     

Circular‐Dichroism Studies on Artemisinin and Epiartemisinin and Their β‐Cyclodextrin Complexes in Solution

The circular dichroism (CD) spectra of the powerful antimalarian active principle artemisinin (ART; 1 ) from Artemisia annua, and of epiartemisinin (EPI, 2), its C(7) epimer, were studied in solution in the presence and absence of β‐cyclodextrin (β‐cd). A significant inversion of sign in the region of the second electronic transition was detected. The rotational strengths were successfully calculated within the time‐dependent density functional theory (DFT), which enabled us to establish a correlation between the molecular recognition and the biological acitivities of the two isomers.