Promoting a Significant Increase in the Photoluminescence Quantum Yield of Terbium(III) Complexes by Ligand Modification.

Two discrete mononuclear complexes, [Tb(bbpen)(NO3)] (I) and [Tb(bbppn)(NO3)] (II), for which H2bbpen = N,N'-bis(2-hydroxybenzyl)-N,N'-bis(pyridin-2-ylmethyl)ethylenediamine and H2bbppn = N,N'-bis(2-hydroxylbenzyl)-N,N'-bis(pyridin-2-ylmethyl)-1,2-propanediamine, were synthesized and characterized by FTIR, Raman, and photoluminescence (PL, steady-state and time-resolved modes) spectroscopy. The attachment of a methyl group to the ethylenediamine portion of the ligand backbone differentiates II from I and acts as a determining feature to both the structural and optical properties of the former. The single-crystal X-ray structure of H2bbppn is described here for the first time, while that of complex II has been redetermined in the monoclinic C2 space group in light of new diffraction data. In II, selective crystallization leads to spontaneous resolution of enantiomeric molecules in different crystals. Absolute emission quantum yields (ϕ) and luminescence excited-state lifetimes (at room temperature and 11 K) were measured for both complexes. Despite their similar molecular structures, I and II exhibit remarkably different ϕ values of 21 ± 2% and 67 ± 7%, respectively, under UV excitation at room temperature. Results of quantum-mechanical (DFT and TD-DFT) calculations and experimental PL measurements also performed for H2bbpen and H2bbppn confirmed that both ligands are suitable to work as "antennas" for TbIII. Considering the 5D4 lifetime profiles and the significantly higher absolute quantum yield of II, it appears that thermally active nonradiative pathways present in I are minimized in II due to differences in the conformation of the ethylenediamine bridge.

Modulatory effect of voriconazole on the production of proinflammatory cytokines in experimental cryptococcosis in mice with severe combined immunodeficiency.

Cryptococcosis is a subacute or chronic disease. For many years, amphotericin B has been used in severe fungal infections. Voriconazole is a triazole with high bioavailability, a large distribution volume, and excellent penetration of the central nervous system (CNS). The objective of this study was to evaluate the production of pro-inflammatory cytokines in the lungs during an experimental infection caused by C. neoformans in murine model (SCID) that was treated with amphotericin B and voriconazole. After intravenous inoculation with 3.0×105 viable yeast cells, the animals were treated with amphotericin B and voriconazole. The daily treatments began 24hours after inoculation and lasted 15 days. We evaluated the survival curve and we measured the levels of TNF-α, IL-6 and IL-10. For all treatments, there was a significant increase in survival compared to the untreated group of animals and the group treated with voriconazole (maximum concentration). The levels of pro-inflammatory cytokines were significantly lower in the groups treated with voriconazole (maximum concentration) and amphotericin B (minimum concentration). Under the conditions studied, we can suggest by that the production of pro-inflammatory cytokines mediated by amphotericin B and voriconazole is dependent on the concentration administered.

Femtosecond Two-Photon Absorption Spectroscopy of Poly(fluorene) Derivatives Containing Benzoselenadiazole and Benzothiadiazole.

We have investigated the molecular structure and two-photon absorption (2PA) properties relationship of two push-pull poly(fluorene) derivatives containing benzoselenadiazole and benzothiadiazole units. For that, we have used the femtosecond wavelength-tunable Z-scan technique with a low repetition rate (1 kHz) and an energy per pulse on the order of nJ. Our results show that both 2PA spectra present a strong 2PA (around 600 GM (1 GM = 1 × 10-50 cm4·s·photon-1)) band at around 720 nm (transition energy 3.45 eV) ascribed to the strongly 2PA-allowed 1Ag-like → mAg-like transition, characteristic of poly(fluorene) derivatives. Another 2PA band related to the intramolecular charge transfer was also observed at around 900 nm (transition energy 2.75 eV). In both 2PA bands, we found higher 2PA cross-section values for the poly(fluorene) containing benzothiadiazole unit. This outcome was explained through the higher charge redistribution at the excited state caused by the benzothiadiazole group as compared to the benzoselenadiazole and confirmed by means of solvatochromic Stokes shift measurements. To shed more light on these results, we employed the sum-over-states approach within the two-energy level model to estimate the maximum permanent dipole moment change related to the intramolecular charge transfer transition.

How to avoid cross contamination during handling resin composites with spatulas / Como evitar a contaminação cruzada durante a manipulação de resinas compostas com espátulas

Incremental technique for resin composite restorations requires multiple physical contacts between spatulas, tooth cavities and the restorative material recipient. Thus, the decontamination of the tip's of spatula by chemical agents between each resin composite increment placement is important to reduce chances of potential cross-contamination. Objectives: To evaluate the efficacy of different solutions for decontamination of tips of spatula used in restorative procedures and to establish a decontamination standard protocol. Material and Methods: Spatulas were sterilized in autoclave at 127°C for 20 minutes and then contaminated with: 1) a suspension of half 1.0 MacFarland scale turbidity of different microorganisms, 2) the pool of equal amounts of these microorganisms; except for the control group. Decontamination techniques consisted of rubbing the tip of the spatulas (1 to 5 consecutive times) using a 2ml 70% ethanol or 2% glutaraldehyde embedded gauze. After decontamination, spatulas were immersed in thioglycolate broth and incubated for 48 hours at 37°C. Broth with visible microbial detection was submitted to bacterial identification by Gram stain. Results: Low uniformity of rubbings number was observed to eliminate different microorganisms due to different tested disinfectant agents. Four or five rubbings were needed to decontamination of the tested microorganisms using 70% ethanol. Three rubbings using 2% glutaraldehyde were able to eliminate tested microorganisms. Conclusion: The results demonstrated that 70% ethanol by friction, counting four or five rubbings, was effective to decontaminate spatula's tip.

A técnica incremental para restaurações de resina composta requer vários contatos físicos entre as espátulas, o preparo cavitário e a embalagem do material restaurador. Assim, a descontaminação da ponta da espátula por meio de agentes químicos entre cada inserção de um novo incremento de resina composta é importante para reduzir as chances de uma potencial de contaminação cruzada. Objetivos: Avaliar a eficácia de diferentes soluções para descontaminação das pontas das espátulas utilizadas em procedimentos restauradores e estabelecer um protocolo padrão de descontaminação. Material e Métodos: espátulas foram esterilizadas em autoclave a 127 °C durante 20 minutos e, em seguida, contaminadas com: 1) uma suspensão de diferentes microorganismos com turbidez equivalente ao padrão 1,0 da escala de McFarland, 2) pool de quantidades iguais destes microrganismos; exceto para o grupo de controle. As técnicas de descontaminação consistiram em esfregar a ponta das espátulas (1 a 5 vezes consecutivas) utilizando 2 ml de álcool 70% ou 2% de glutaraldeído embebidos em gazes. Após a descontaminação, as espátulas foram imersas em caldo de tioglicolato e incubadas durante 48 horas a 37 °C. O caldo com visível detecção microbiana foi submetido à identificação bacteriana pela coloração de Gram. Resultados: Baixa uniformidade do esfregaço foi observada para a eliminação de diferentes microrganismos, devido aos diferentes agentes desinfetantes testados. Quatro ou cinco esfregaços foram necessários para a descontaminação dos microrganismos testados usando álcool 70%. Três esfregaços na espátula usando glutaraldeído a 2% foram capazes de eliminar os microrganismos testados. Conclusão: Os resultados demonstraram que o álcool 70% por fricção, contando quatro ou cinco esfregaços na espátula com gazes embebida nas soluções desinfetantes, foi eficaz para descontaminar a ponta da espátula.

A single intraperitoneal injection of ketamine does not affect spatial working, reference memory or neurodegeneration in adult mice: An animal study.

BACKGROUND: Ketamine is an anaesthetic and analgesic drug used in research and clinical practice. Little is known about the effects of different doses of this drug on memory and brain cellular death. OBJECTIVE: To study the effects of different doses of ketamine on working and reference memory, and neurodegeneration in adult mice. DESIGN: A randomised study. SETTINGS: The study was carried out in a basic science laboratory, between March 2011 and August 2012. ANIMALS: Forty-eight 7-month-old, male C57BL/6 mice were used. INTERVENTION: Animals received a single intraperitoneal injection of physiological saline solution or one of three doses of ketamine (25, 75 or 150 mg kg(-1)). Each group consisted of 12 animals (seven animals for behavioural tests and five animals for histopathological and immunohistochemical studies). The animals used for histopathology studies were sacrificed 3 h after anaesthesia. MAIN OUTCOME MEASURES: Working and reference memories were assessed using the radial-maze test over 12 consecutive days. The equilibrium was tested using the vertical pole (4 and 24 h after injection), whereas locomotion was assessed using the open field (24, 48 and 72 h after injection). Histopathological (haematoxylin-eosin staining) and immunohistochemical analyses (procaspase-3 and activated caspase-3 detections) were performed 3 h after injection to assess neurodegeneration in the retrosplenial and visual cortices, pyramidal cell layer of the cornu Ammonis 1 and cornu Ammonis 3 areas of the hippocampus, in the granular layer of the dentate gyrus, in the laterodorsal thalamic nucleus, striatum and accumbens nucleus. RESULTS: No significant differences were observed between the groups regarding the number of dead cells and cells showing positive immune-reactivity in the different regions of the brain studied. The performance in the vertical pole test and the number of reference and working memory errors in the radial-maze were similar in all groups. Nevertheless, the animals treated with ketamine 75 mg kg(-1) were transiently more active, walking a greater total distance at a greater speed in the open field than other groups (power of 0.96). CONCLUSION: These data indicate that a single intraperitoneal injection of ketamine at subanaesthetic and anaesthetic doses does not impair working memory, reference memory or neurodegeneration in adult mice, but an intermediate dose of ketamine produces transitory hyperlocomotion.

Electronic structure and optical properties of an alternated fluorene-benzothiadiazole copolymer: interplay between experimental and theoretical data.

The donor-acceptor copolymer containing benzothiadiazole (electron acceptor), linked to functionalized fluorene (electron donor), [poly[9,9-bis(3'-(tert-butyl propanoate))fluorene-co-4,7-(2,1,3-benzothiadiazole)] (LaPPS40), was synthesized through the Suzuki route. The polymer was characterized by scanning electron microscopy, gel permeation chromatography, NMR, thermal analysis, cyclic voltammetry, X-ray photoelectron spectroscopy, UV-vis spectrometry, and photophysical measurements. Theoretical calculations (density functional theory and semiempirical methodologies) used to simulate the geometry of some oligomers and the dipole moments of molecular orbitals involved were in excellent agreement with experimental results. Using such data, the higher energy absorption band was attributed to the π-π* (S(0) → S(4)) transition of the fluorene units and the lower lying band was attributed to the intramolecular (ICT) (S(0) → S(1)) charge transfer between acceptor (benzothiadiazole) and donor groups (fluorene) (D-A structure). The ICT character of this band was confirmed by its solvatochromic properties using solvents with different dielectric properties, and this behavior could be well described by the Lippert-Mataga equation. To explain the solvatochromic behavior, both the magnitude and orientation of the dipole moments in the electronic ground state and in the excited state were analyzed using the theoretical data. According to these data, the change in magnitude of the dipole moments was very small for both transitions but the spatial orientation changed remarkably for the lower energy band ascribed to the ICT band.

Correlation of the acid-sensitivity of polyethylene glycol daunorubicin conjugates with their in vitro antiproliferative activity.

Polyethylene glycol conjugates with linkers of varying acid-sensitivity were prepared by reacting five maleimide derivatives of daunorubicin containing an amide bond (1) or acid-sensitive carboxylic hydrazone bonds (2-5) with alpha-methoxy-poly(ethylene glycol)-thiopropionic acid amide (MW 20000) or alpha,omega-bis-thiopropionic acid amide poly(ethylene glycol) (MW 20000). The polymer drug derivatives were designed to release daunorubicin inside the tumor cell by acid-cleavage of the hydrazone bond after uptake of the conjugate by endocytosis. In subsequent cell culture experiments, the order of antitumor activity of the PEG daunorubicin conjugates correlated with their acid-sensitivity as determined by HPLC (cell lines: BXF T24 bladder carcinoma and LXFL 529L lung cancer cell line; assay: propidium iodide fluorescence assay). The acid-sensitivity of the link between PEG and daunorubicin is therefore an important parameter for in vitro efficacy.