Synthesis and characterization of triosmium and triruthenium pyrene clusters

The reaction between 1-pyrenecarboxaldehyde (C₁₆H₉CHO) and the labile triosmium cluster [Os₃(CO)₁₀(CH₃CN)₂] gives rise to the formation of two new compounds by competitive oxidative addition between the aldehydic group and an arene C-H bond, to afford the acyl complex [Os₃(CO)₁₀(μ-H)(μ-COC₁₆H₉)] (1) and the compound [Os₃(CO)₁₀(μ-H) (C₁₆H₈CHO)] (2), respectively. Thermolysis of [Os₃(CO)₁₀(μ-H)(μ-C₁₆H₉CO)] (1) in n-octane affords two new complexes in good yields, [Os₃(CO)₉(μ-H)₂(μ-COC₁₆H₈)] (3) and the pyryne complex [Os₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (4).In contrast, when 1-pyrenecarboxaldehyde reacts with [Ru₃(CO)₁₂] only one product is obtained, [Ru₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (5), a nonacarbonyl cluster bearing a pyrene ligand. All compounds were characterized by analytical and spectroscopic data, and crystal structures for 1, 2, 4 and 5 were obtained.     

Designed synthesis of metal-organic frameworks containing gold(I) cations supported in phosphazene-phosphine polymeric matrices

The reaction of the polyphosphazenes {[NP(O₂C₁₂H₈)]_1−x[NP(OC₆H₄PPh₂)₂]_x}_n, x = 0.15 (1a), 0.25 (1b), 0.35 (1c), with [Au(THT)Cl] (THT = tetrahydrothiophene) in dichloromethane gave the polymers {[NP(O₂C₁₂H₈)]_1−x[NP(OC₆H₄PPh₂AuCl)₂]_x}_n, x = 0.15, (2a), 0.25 (2b), 0.35 (2c), respectively. The reaction of (1a) with [Au(PPh₃)₂]PF₆ in refluxing THF led to the replacement of the PPh₃ ligands giving a metal-organic framework of idealized formula {[NP(O₂C₁₂H₈)]_1−x[NP(OC₆H₄PPh₂)₂(AuPF₆)_0.5]_x}_n, x = 0.15, (3a), 0.25 (3b) containing cationic [-Ph₂P-Au⁺-PPh₂-] cross-linking sites. The insoluble polymeric matrix (3a), having pendant PPh₂ groups, was reacted with [Au(THT)Cl] to give the new polymeric framework of composition {[NP(O₂C₁₂H₈)]_0.85[NP(OC₆H₄PPh₂)₂(AuPF₆)_0.5(AuCl)_0.5]_0.15}_n (4).     

Synthesis,structural characterization and ionic conductivity of NASICON-type Ba<Subscript>x/2</Subscript>Li<Subscript>1-x</Subscript>Ti<Subscript>2</Subscript>(PO<Subscript>4</Subscript>)<Subscript>3</Subscript> (0.4 ≤ x ≤ 1) materials

The NASICON series, with formula Ba_x/2Li_1-xTi₂(PO₄)₃ (0.4 ≤ x ≤ 1), has been prepared by solid-state reaction and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman, nuclear magnetic resonance (NMR) and impedance spectroscopy (IS). XRD patterns of samples indicated the formation of single phases with rhombohedral structure (space group R-3c). The Rietveld analysis of XRD patterns was performed to deduce location of Li and Ba ions. FTIR, Raman, and NMR techniques showed the only presence of isolated PO₄ groups in analyzed phosphates. ³¹P MAS-NMR spectra were used to investigate Li and Ba distribution and ⁷Li MAS-NMR spectra to discriminated Li ions with different mobility in conduction paths. A maximum total conductivity of 2.5 × 10^?7 S cm^?1 and a minimum activation energy of 0.47 eV were obtained at room temperature for Ba_0.3Li_0.4Ti₂(PO₄)₃ (x = 0.6).     

Negative S parameter from holographic technicolor

We present a new class of 5D models, Holographic Technicolor, which fulfills the basic requirements for a candidate of comprehensible 4D strong dynamics at the electroweak scale. It is the first Technicolor-like model able to provide a vanishing or even negative tree-level S parameter, avoiding any no-go theorem on its sign. The model is described in the large-N regime. S is therefore computable: possible corrections coming from boundary terms follow the 1/N suppression, and generation of fermion masses and the S parameter issue do split up. We investigate the model's 4D dual, probably walking Technicolor-like with a large anomalous dimension.     

Electrochemical Portable Method for on site Screening of Scopolamine in Beverage and Urine Samples

Scopolamine (SCP) is a psychoactive drug often added to beverages for recreational or abuse purposes (loss of memory and non‐consensual practices). In this work, a simple and portable method for fast in field screening of SCP in beverage (beer, coke, energy drink, sugarcane spirit, vodka, and whisky) and urine samples is presented. The proposed method is based on batch injection analysis with square wave voltammetric (BIA‐SWV) detection using boron‐doped diamond (BDD) as the working electrode. A voltammetric profile with accurate information on the presence or absence of SCP is obtained using a small sample volume (～50 μL) and a simple sample pretreatment step (dilution in supporting electrolyte). Around two hundred analyses are possible using the proposed system (injection of single sample plug – 120 μL) without the need of electrodes handling or supporting electrolyte exchange (friendly to point‐of‐care or on site screenings). The quantification of SCP in beverages is also possible using the proposed portable protocol, with a limit of detection of 0.18 μmol L^?1 and recovery values between 87 to 113 %.     

Screening of north-east Mexico medicinal plants with activities against herpes simplex virus and human cancer cell line

The plants examined in this study have previous biological activity reports indicating the possibility of found activity against herpes and cancer cell. The aim of this contribution was to carry out a screening of Juglans mollis (Juglandaceae), Persea americana (Lauraceae), Hamelia patens (Rubiaceae), Salvia texana (Lamiaceae), Salvia ballotaeflora (Lamiaceae), Ceanothus coeruleus (Rhamnaceae), Chrysactinia mexicana (Asteraceae) y Clematis drummondii (Ranunculaceae), against HeLa cells, VHS-1 and VHS-2. The method MTT was used to determine the 50% cytotoxic concentration (CC₅₀), in Vero and HeLa cell lines. To determine the 50% inhibitory concentration (IC₅₀) against herpes, the plaque reduction method was used. Results showed that none of the plants exhibited activity against HeLa cells. About antiherpetic activity, J. mollis and S. ballotaeflora extracts present antiherpetic activity in terms of their SI, increasingly interest for further studies on the isolation of compounds with antiherpetic activity and about the mechanisms of action that produce this activity.     

Rapid method for simultaneous determination of ascorbic acid and zinc in effervescent tablets by capillary zone electrophoresis with contactless conductivity detection

Ascorbic acid and zinc are essential nutrients that play important roles in nutrition, immune support, and maintenance of health. For this reason, both compounds are widely used as ingredients in dietary supplements. We report, for the first time, an analytical method for fast simultaneous determination of ascorbic acid and zinc. A single analysis run is possible every 80 s (45 injections/h). The method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection using a fused silica capillary with 50 cm length (effective length of 10 cm). The separation was achieved by using a background electrolyte composed by 30 mmol/L of 2‐(morpholin‐4‐yl)ethane‐1‐sulfonic acid and 30 mmol/L of histidine, pH 6.1. The detection limits were 10 and 20 μmol/L and recovery values for spiked samples were 101 and 100% for zinc and ascorbic acid, respectively. The results obtained with the developed procedure were compared to those obtained by titration (ascorbic acid) and flame atomic absorption spectroscopy (zinc), and no statistically significant differences were observed (95% confidence level).     

Small molecule microarray screening methodology based on surface plasmon resonance imaging

In order to increase the scope and utility of small molecule microarrays (SMMs) we have combined SMMs and SPRi to screen small molecule antagonists against protein targets. Several small molecules, including immunosuppressive drugs (rapamycin and FK506) and reported inhibitors (FOBISIN and Blapsin) of 14-3-3ζ proteins have been used to validate this technology. Furthermore, a small library of isatin derivatives have been synthesized and screened on developed platform against 14-3-3ζ protein. Three molecules, derived from the endogenous intermediate isatin termed, FZIB-35, FZIB-36 and FZIB-38 were identified as novel inhibitors which shows significant interaction with 14-3-3ζ. A mutation in the binding groove of 14-3-3ζ, (K49E), almost abolishes the binding of these compounds to 14-3-3ζ protein. To exclude the probability of false positives, two more purified proteins (PtpA and BirA) were also tested. Furthermore, in order to confirm the binding pocket specificity, competition assay against R18 peptide was also carried out on presented platform. We show that SMMs in combination with SPRi are a powerful method to identify lead compounds in high throughput manner without the need to develop an activity based assay.     

Structure and fluctuations of the premelted liquid film of ice at the triple point

ABSTRACT

In this paper, we study the structure of the ice/vapour interface in the neighbourhood of the triple point for the TIP4P/2005 model. We probe the fluctuations of the ice/film and film/vapour surfaces that separate the liquid film from the coexisting bulk phases at basal, primary prismatic and secondary prismatic planes. The results are interpreted using a coupled sine Gordon plus Interface Hamiltonian model. At large length scales, the two bounding surfaces are correlated and behave as a single complex ice/vapour interface. For small length, on the contrary, the ice/film and film/vapour surfaces behave very much like independent ice/water and water/vapour interfaces. The study suggests that the basal facet of the TIP4P/2005 model is smooth, the prismatic facet is close to a roughening transition, and the secondary prismatic facet is rough. For the faceted basal face, our fluctuation analysis allows us to estimate the step free energy in good agreement with experiment. Our results allow for a quantitative characterisation of the extent to which the adsorbed quasi-liquid layer behaves as water and explains experimental observations which reveal similar activation energies for crystals grown in bulk vapour or bulk water.     

Trajectory-Based Interpretation of Laser Light Diffraction by a Sharp Edge

In the diffraction pattern produced by a half-plane sharp edge when it obstructs the passage of a laser beam, two characteristic regions are noticeable. There is a central region, where the diffraction of laser light appears in the region of geometric shadow, while intensity oscillations are observed in the non-obstructed area. On both sides of the edge, there are also very long light traces along the normal to the edge of the obstacle. The theoretical explanation of this phenomenon is based on the Fresnel–Kirchhoff diffraction theory applied to the Gaussian beam propagation behind the obstacle. In this paper, we supplement this explanation by considering electromagnetic flow lines, which provide a more complete interpretation of the phenomenon in terms of electric and magnetic fields and flux lines; at the same time, that can be related to average photon paths.