Endoscopic treatment of bleeding gastric varices with histoacryl (N-butyl-2-cyanoacrylate): a South European single center experience

BACKGROUND: Endoscopic injection of N-butyl-2-cyanoacrylate is the current recommended treatment for gastric variceal bleeding. Despite the extensive worldwide use, there are still differences related to the technique, safety, and long term-results. We retrospectively evaluated the efficacy and safety of cyanoacrylate in patients with gastric variceal bleeding. PATIENTS AND METHODS: Between January 1998 and January 2010, 97 patients with gastric variceal bleeding underwent endoscopic treatment with a mixture of N-butyl-2-cyanoacrylate and Lipiodol(TM). Ninety-one patients had cirrhosis and 6 had non-cirrhotic portal hypertension. Child-Pugh score at presentation for cirrhotic patients was A-12.1 %; B-53.8 %; C-34.1 % and median MELD score at admission was 13 (3-26). Successful hemostasis, rebleeding rate and complications were reviewed. Median time of follow up was 19 months (0.5-126). RESULTS: A median mixture volume of 1.5 mL (0.6 to 5 mL), in 1 to 8 injections, was used, with immediate hemostasis rate of 95.9 % and early rebleeding rate of 14.4 %. One or more complications occurred in 17.5 % and were associated with the use of Sengstaken-Blakemore tube before cyanoacrylate and very early rebleeding (p < 0.05). Hospital mortality rate during initial bleeding episode was 9.3 %. Very early rebleeding was a strong and independent predictor for in-hospital mortality (p < 0.001). Long-term mortality rate was 58.8 %, in most of the cases secondary to hepatic failure. CONCLUSION: N-butyl-2-cyanoacrylate is a rapid, easy and highly effective modality for immediate hemostasis of gastric variceal bleeding with an acceptable rebleeding rate. Patients with very early rebleeding are at higher risk of death

Aggregation-induced emission of [3]cumulenes functionalized with heptagon-containing polyphenylenes

This is accepted manuscript, the final published article is available in "García Jiménez, V.; et al. Aggregation-induced emission of [3]cumulenes functionalized with heptagon-containing polyphenylenes. Chemical Communications, online (2018). DOI: http://dx.doi.org/10.1039/C8CC00386FWe report the luminiscence at room temperature by aggregate formation of [3]cumulenes functionalized with propeller-like heptagon-containing polyphenylenes. These endgroups turn on the emission of a [3]cumulene by steric protection and restriction of their intramolecular rotations in the aggregates.European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (ERC-2015 -677023).Ministerio de Economía y Competitividad (MINECO, Spain – FEDER) (CTQ2015-70283-P, CTQ2014-53598-R, RyC-2013-12943).Fundação para a Ciência e a tecnologia (Portugal, IF/00759/2013, SFRH/BPD/75782/2011,SFRH/BPD/96707/2013,UID/NAN/50024/2013)

New triazine bridged triads based on BODIPY-porphyrin systems: extended absorption, efficient energy transfer and upconverted emission

Two novel triads connecting a BODIPY to ethylenediamine substituted porphyrins via triazine linker have been synthesized and characterized. One of the triads is a linear D-A structure with one BODIPY (D) and one porphyrin (A) bridged by the triazine linker and the other one is a branched A-D4 structure with the porphyrin core linked to four BODIPY units. The triads show extended absorption in the visible region with contributions from both porphyrin (Soret band centred at 410–430 nm) and BODIPY units (strong absorption at ≈ 502 nm) in good agreement with the expected molar ratio. Both triads exhibit linear and nonlinear optical properties featuring an efficient energy transfer from the BODIPY donor to the porphyrin acceptor. The nonlinear upconverted emission properties of the triads were studied by two-photon excitation in the Near-infrared (NIR, 710–930 nm). The maximum two-photon absorption cross-section values for the triads (40–70 GM) are larger than those typically reported in this wavelength range for porphyrins and BODIPY. Both the green emission of BODIPY (≈514 nm) and the red emission of porphyrins (650–750 nm) were observed under NIR excitation at 930 nm. The distinct features of triads, namely i) an extended absorption; ii) an efficient energy transfer and iii) the nonlinear upconverted emission featuring a large separation between the excitation and emission wavelengths could be beneficial for application in sensing and imaging procedures.publishe

Aggregation of coronene: The effect of carboxyl and amine functional groups

10 pags., 9 figs., 4 tabs.The aggregation of coronene is relevant to understand the formation of carbon nanomaterials, including graphene quantum dots (GQDs) that show exceptional photophysical properties. This article evaluates the influence of carboxyl and amine substituting groups on the aggregation of coronene by performing a global optimization study based on a new potential energy surface. The structures of clusters with substituted coronene are similar to those formed by un-substituted monomers, that is, stacked (non-stacked) motifs are favoured for small-size (large-size) clusters. Nonetheless, the presence of carboxyl and amine groups leads to an increase of the number of local minima of comparable energy. The clusters with substituted monomers have also shown to enhance the attractive component interaction, which can be attributed to weak induction and charge transfer effects and to stronger electrostatic contributions. Moreover, the calculated height of magic-number structures of the clusters in this work is compatible with the morphology of the GQDs reported in the literature. This journal isJ. M. C. M. acknowledges the support from the Coimbra Chemistry Centre (CQC), which is financed by the Portuguese ‘‘Fundaçao para a Ciencia e a Tecnologia’’ (FCT) through the programmes UIDB/ 00313/2020 and COMPETE. We are also grateful for the provision of computational time in the supercomputer resources hosted at Laboratorio de Computaça˜o Avançada, Universidade de Coimbra. M. B. acknowledges financial support by the Spanish ‘‘Ministerio de Ciencia e Innovacion’’ for the FIS2017-84391-C2-2-P grant as well as the allocation of computing time by CESGA supercomputing center (Spain). E. M., J. M. G. M. and C. F. O. C. thank FCT for funding: PTDC/NAN-MAT/29317/2017, UIDB/00100/2020 and PD/ BD/127805/2016

Nonlinear emission of quinolizinium-based dyes with application in fluorescence lifetime imaging

© 2014 American Chemical Society.Charged molecules based on the quinolizinum cation have potential applications as labels in fluorescence imaging in biological media under nonlinear excitation. A systematic study of the linear and nonlinear photophysics of derivatives of the quinolizinum cation substituted by either dimethylaniline or methoxyphenyl electron donors is performed. The effects of donor strength, conjugation length, and symmetry in the two-photon emission efficiency are analyzed in detail. The best performing nonlinear fluorophore, with two-photon absorption cross sections of 1140 GM and an emission quantum yield of 0.22, is characterized by a symmetric D-π-A(+)-π-D architecture based on the methoxyphenyl substituent. Application of this molecule as a fluorescent marker in optical microscopy of living cells revealed that, under favorable conditions, the fluorophore can be localized in the cytoplasmatic compartment of the cell, staining vesicular shape organelles. At higher dye concentrations and longer staining times, the fluorophore can also penetrate into the nucleus. The nonlinearly excited fluorescence lifetime imaging shows that the fluorophore lifetime is sensitive to its location in the different cell compartments. Using fluorescence lifetime microscopy, a multicolor map of the cell is drafted with a single dye.The authors acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (Project CTQ2011-24715), the Portuguese Fundação para a Ciência e a Tecnologia (Projects PTDC/CTM-POL/114367/2009, RECI/CTM-POL/0342/2012) and a grant from the Universidad de Alcalá (TC).info:eu-repo/semantics/publishedVersio

Conformational Switching Induced by Near-Infrared Laser Irradiation

This work describes a molecular system where it is possible to effectively control the interconversion between two different stable conformational states, using selective narrow-band near-infrared irradiation. Monomers of hydroxyacetone (HA) isolated in low temperature argon matrices at 15 K exist exclusively in the conformational ground state Cc. Narrow-band near-infrared vibrational excitation of the first OH stretching overtone of the Cc form resulted in conformational isomerization. The photoproduct was identified as the higher energy Tt conformer of HA, and it was found to be stable at 15 K. The reverse isomerization, converting Tt into Cc, could also be induced by laser excitation of the first OH stretching overtone of the Tt form. The interpretation of the experimental observations was supported by anharmonic and harmonic calculations of the vibrational spectra and barriers to intramolecular rotation