594 research outputs found

    Copper and Zinc Metal–Organic Frameworks with Bipyrazole Linkers Display Strong Antibacterial Activity against Both Gram+ and Gram− Bacterial Strains

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    : Here, we report a new synthetic protocol based on microwave-assisted synthesis (MAS) for the preparation of higher yields of zinc and copper in MOFs based on different bis(pyrazolyl)-tagged ligands ([M(BPZ)]n where M = Zn(II), Cu(II), H2BPZ = 4,4'-bipyrazole, [M(BPZ-NH2)]n where M = Zn(II), Cu(II); H2BPZ-NH2 = 3-amino-4,4'-bipyrazole, and [Mx(Me4BPZPh)] where M = Zn(II), x = 1; Cu(II), x = 2; H2Me4BPZPh = bis-4'-(3',5'-dimethyl)-pyrazolylbenzene) and, for the first time, a detailed study of their antibacterial activity, tested against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, as representative agents of infections. The results show that all MOFs exert a broad-spectrum activity and strong efficiency in bacterial growth inhibition, with a mechanism of action based on the surface contact of MOF particles with bacterial cells through the so-called "chelation effect" and reactive oxygen species (ROS) generation, without a significant release of Zn(II) and Cu(II) ions. In addition, morphological changes were elucidated by using a scanning electron microscope (SEM) and bacterial cell damage was further confirmed by a confocal laser scanning microscopy (CLSM) test

    Steric and Electronic Effects Responsible for N, O- or N, N-Chelating Coordination of Pyrazolones Containing a Pyridine Ring in Ruthenium Arene Systems

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    Structural and electronic factors are crucial to rationalize the different N,O or N,N chelating coordination of pyrazolones containing a pyridine ring. The reactivity of proligand 3-phenyl-1-(pyridin-2-yl)-5-pyrazolone (HLpy,ph) with the (arene)Ru(II) fragment was explored. Neutral and ionic (arene)Ru(II) complexes were obtained and fully characterized, also by X-ray diffraction, revealing the ligand to coordinate in an unusual N,O-chelating fashion. Other ruthenium complexes were also synthesized with 3-methyl-1-(pyridin-2-yl)-5-pyrazolone (HLpy,me) and 3-methyl-1-(pyridin-2-yl)-4-trifluoroacetyl-5-pyrazolone (HQpy,CF3). In these complexes the ligands adopt the preferred N,N-chelating mode. Ligands and complexes were theoretically analyzed by density functional theory (DFT). The most stable tautomer of HLpy,phmatched well with the experimental behavior of this proligand and the structures of Ru-complexes were well described by calculations. The thermodynamic stability of the N,O- and N,N-coordination modes was analyzed and a proposal for the achievement of the N,O-coordination mode in complexes 1-4 was proposed. Cytotoxicity tests were performed against human ovarian carcinoma (A2780 and Cisplatin-resistant A2780cis) and nontumorigenic human embryonic kidney (HEK293T) cell lines, showing the free ligands to be more cytotoxic that the ensuing (arene)Ru(II) complexes

    Executable Digital Process Twins: Towards the Enhancement of Process-Driven Systems

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    The development of process-driven systems and the advancements in digital twins have led to the birth of new ways of monitoring and analyzing systems, i.e., digital process twins. Specifically, a digital process twin can allow the monitoring of system behavior and the analysis of the execution status to improve the whole system. However, the concept of the digital process twin is still theoretical, and process-driven systems cannot really benefit from them. In this regard, this work discusses how to effectively exploit a digital process twin and proposes an implementation that combines the monitoring, refinement, and enactment of system behavior. We demonstrated the proposed solution in a multi-robot scenario

    Multiple-locus variable-number tandem repeat analysis of reference strains used for the diagnosis of leptospirosis in Argentina

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    Leptospirosis is a worldwide zoonosis caused by a spirochete that belongs to the genus Leptospira. In the last years, new methods, such as the PCR-based multiple-locus variable-number tandem repeat analysis (MLVA), have been developed for the genotyping of leptospires. In the present work, the MLVA patterns for all reference strains used in Argentina for bovine, ovine, porcine, equine, caprine and canine leptospirosis diagnosis, as well as in human and wild animal diagnosis, were obtained. MLVA results are presented in such a way that they can be readily used for the identification of these strains by the simple and direct comparison of agarose gels. Making the use and interpretation of the MLVA for leptospires typing easier will help increase the use of this method as a routine procedure for human and animal diagnosis, for epidemiological studies, vaccine control and other applications.Fil:Pettinari, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

    Chemical behavior and in vitro activity of mixed phosphine gold(I)compounds on melanoma cell lines.

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    7partially_openCARUSO F; PETTINARI C; PADUANO F; VILLA R; MARCHETTI F; E. MONTI; ROSSI MCaruso, F; Pettinari, C; Paduano, F; Villa, R; Marchetti, F; Monti, ELENA CATERINA; Rossi, M

    Ruthenium(II) Arene Complexes Bearing Tris(pyrazolyl)methanesulfonate Capping Ligands.Electrochemistry, Spectroscopic, and X-ray Structural Characterization

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    Novel [Ru(L)(Tpms)]Cl and [Ru(L)(Tpms(Ph))]Cl complexes (L = p-cymene, benzene, or hexamethylbenzene, Tpms = tris(pyrazolyl)-methanesulfonate, Tpms(Ph) = tris(3-phenylpyrazoly)methanesulfonate) have been prepared by reaction of [Ru(L)(mu-Cl)(2)](2) with Li[Tpms] and Li[Tpms(Ph)], respectively. [Ru(p-cymene)(Tpms)]BF4 has been synthesized through a metathetic reaction of [Ru(p-cymene)(Tpms)]Cl with AgBF4. [RuCl(cod)(Tpms)] (cod = 1,5-cyclooctadiene) and [RuCl(cod)(Tpms(Ph))] are also reported, being obtained by reaction of [RuCl2(cod)(MeCN)(2)] with Li[Tpms] and Li[Tpms(Ph)], respectively. The structures of the complexes and the coordination modes of the ligands have been established by IR, NMR, and single-crystal X-ray diffraction (for [RuL(Tpms)]X (L = p-cymene or HMB, X = Cl; L = p-cymene, X = BF4)) studies. Electrochemical studies showed that each complex undergoes a single-electron R-II -> R-III oxidation at a potential measured by cyclic voltammetry, allowing to compare the electron-donor characters of the tris(pyrazolyl)methanesulfonate and arene ligands, and to estimate, for the first time, the values of the Lever E-L ligand parameter for Tmps(Ph), HMB, and cod

    Kinetic Inductance Detectors for the OLIMPO experiment: design and pre-flight characterization

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    We designed, fabricated, and characterized four arrays of horn--coupled, lumped element kinetic inductance detectors (LEKIDs), optimized to work in the spectral bands of the balloon-borne OLIMPO experiment. OLIMPO is a 2.6 m aperture telescope, aimed at spectroscopic measurements of the Sunyaev-Zel'dovich (SZ) effect. OLIMPO will also validate the LEKID technology in a representative space environment. The corrected focal plane is filled with diffraction limited horn-coupled KID arrays, with 19, 37, 23, 41 active pixels respectively at 150, 250, 350, and 460 \:GHz. Here we report on the full electrical and optical characterization performed on these detector arrays before the flight. In a dark laboratory cryostat, we measured the resonator electrical parameters, such as the quality factors and the electrical responsivities, at a base temperature of 300 \:mK. The measured average resonator QQs are 1.7×104\times{10^4}, 7.0×104\times{10^4}, 1.0×104\times{10^4}, and 1.0×104\times{10^4} for the 150, 250, 350, and 460 \:GHz arrays, respectively. The average electrical phase responsivities on resonance are 1.4 \:rad/pW, 1.5 \:rad/pW, 2.1 \:rad/pW, and 2.1 \:rad/pW; the electrical noise equivalent powers are 45 aW/Hz\:\rm{aW/\sqrt{Hz}}, 160 aW/Hz\:\rm{aW/\sqrt{Hz}}, 80 aW/Hz\:\rm{aW/\sqrt{Hz}}, and 140 aW/Hz\:\rm{aW/\sqrt{Hz}}, at 12 Hz. In the OLIMPO cryostat, we measured the optical properties, such as the noise equivalent temperatures (NET) and the spectral responses. The measured NETRJ_{\rm RJ}s are 200 μKs200\:\mu\rm{K\sqrt{s}}, 240 μKs240\:\mu\rm{K\sqrt{s}}, 240 μKs240\:\mu\rm{K\sqrt{s}}, and  340μKs\:340\mu\rm{K\sqrt{s}}, at 12 Hz; under 78, 88, 92, and 90 mK Rayleigh-Jeans blackbody load changes respectively for the 150, 250, 350, and 460 GHz arrays. The spectral responses were characterized with the OLIMPO differential Fourier transform spectrometer (DFTS) up to THz frequencies, with a resolution of 1.8 GHz.Comment: Published on JCA

    A lithographic approach for quantum dot-photonic crystal nanocavity coupling in dilute nitrides

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    We report on a novel lithographic approach for the fabrication of integrated quantum dot (QD)-photonic crystal (PhC) nanocavity systems. We exploit unique hydrogen's ability to tailor the band gap energy of dilute nitride semiconductors to fabricate isolated site-controlled QDs via a spatially selective hydrogenation at the nanometer-scale. A deterministic integration of the realized site-controlled QDs with PhC nanocavities is provided by the inherent realignment precision (~ 20 nm) of the electron beam lithography system used for the fabrication of both QDs and PhC cavities. A detailed description of the fabrication steps leading to the realization of integrated QD-PhC cavity systems is provided, together with the experimental evidence of a weak coupling effect between the single-photon emitter and the PhC cavity
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