NMR Signatures and Electronic Structure of Ti Sites in Titanosilicalite-1 from Solid-State 47/49Ti NMR Spectroscopy.

Although titanosilicalite-1 (TS-1) is among the most successful oxidation catalysts used in industry, its active site structure is still debated. Recent efforts have mostly focused on understanding the role of defect sites and extraframework Ti. Here, we report the 47/49Ti signature of TS-1 and molecular analogues [Ti(OTBOS)4] and [Ti(OTBOS)3(OiPr)] using novel MAS CryoProbe to enhance the sensitivity. While the dehydrated TS-1 displays chemical shifts similar to those of molecular homologues, confirming the tetrahedral environment of Ti consistent with X-ray absorption spectroscopy, it is associated with a distribution of larger quadrupolar coupling constants, indicating an asymmetric environment. Detailed computational studies on cluster models highlights the high sensitivity of the NMR signatures (chemical shift and quadrupolar coupling constant) to small local structural changes. These calculations show that, while it will be difficult to distinguish mono- vs dinuclear sites, the sensitivity of the 47/49Ti NMR signature should enable distinguishing the Ti location among specific T site positions.

Technical Synthesis of 1,5,9-Cyclododecatriene Revisited: Surprising Byproducts from a Venerable Industrial Process.

The synthesis of 1,5,9-cyclododecatriene by selective trimerization of butadiene catalyzed by TiCl4 and ethylaluminum sesquichloride has been commercially used since 1965. Although thoroughly investigated, not all details of the mechanism are completely understood. The recent development of a new process to produce cyclododecanone involving oxidation of 1,5,9-cyclododecatriene with N2O has led to the serendipitous discovery of an array of hitherto unknown byproducts, formed in the trimerization of butadiene: eleven tricyclic C12H20 and one tetracyclic C12H18 hydrocarbons, three of which had never been described before. The identification of these byproducts became possible by using a combination of chemical enrichment, high-resolution distillation, 13C-2D-INADEQUATE NMR, and comparison with ab initio calculated spectra, thus demonstrating the power of these combined techniques. The identification of these byproducts contributes to a better understanding of the mechanism of this centrally important reaction.

Across the Board: J.†Henrique Teles.

In this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Dr. J. Henrique Teles, who highlights the importance of a holistic view of sustainability. This is particularly important when it comes to bringing results from the lab to industrial use.

Haematopoietic stem cells: entropic landscapes of differentiation.

The metaphor of a potential epigenetic differentiation landscape broadly suggests that during differentiation a stem cell approaches a stable equilibrium state from a higher free energy towards a stable equilibrium state which represents the final cell type. It has been conjectured that there is an analogy to the concept of entropy in statistical mechanics. In this context, in the undifferentiated state, the entropy would be large since fewer constraints exist on the gene expression programmes of the cell. As differentiation progresses, gene expression programmes become more and more constrained and thus the entropy would be expected to decrease. In order to assess these predictions, we compute the Shannon entropy for time-resolved single-cell gene expression data in two different experimental set-ups of haematopoietic differentiation. We find that the behaviour of this entropy measure is in contrast to these predictions. In particular, we find that the Shannon entropy is not a decreasing function of developmental pseudo-time but instead it increases towards the time point of commitment before decreasing again. This behaviour is consistent with an increase in gene expression disorder observed in populations sampled at the time point of commitment. Single cells in these populations exhibit different combinations of regulator activity that suggest the presence of multiple configurations of a potential differentiation network as a result of multiple entry points into the committed state.

Evidence-based guides in tracheostomy use in critical patients

Objetivos: Proporcionar guías de traqueostomía para el paciente crítico, basadas en la evidencia científica disponible, y facilitar la identificación de áreas en las cuales se requieren mayores estudios. Métodos: Un grupo de trabajo formado con representantes de 10 países pertenecientes a la Federación Panamericana e Ibérica de Sociedades de Medicina Crítica y Terapia Intensiva y a la Latin American Critical Care Trial Investigators Network(LACCTIN) desarrollaron estas recomendaciones basadas en el sistema Grading of Recommendations Assessment, Development and Evaluation (GRADE). Resultados: El grupo identificó 23 preguntas relevantes entre las 87 preguntas planteadas inicialmente. En la búsqueda inicial de la literatura se identificaron 333 estudios, de los cuales se escogieron un total de 226. El equipo de trabajo generó un total de 19 recomendaciones: 10 positivas (1B = 3, 2C = 3, 2D = 4) y 9 negativas (1B = 8, 2C = 1). En 6 ocasiones no se pudieron establecer recomendaciones. Conclusión: La traqueostomía percutánea se asocia a menor riesgo de infecciones en comparación con la traqueostomía quirúrgica. La traqueostomía precoz solo parece reducir la duración de la ventilación mecánica pero no la incidencia de neumonía, la duración de la estancia hospitalaria o la mortalidad a largo plazo. La evidencia no apoya el uso de broncoscopia de forma rutinaria ni el uso de máscara laríngea durante el procedimiento. Finalmente, el entrenamiento adecuado previo es tanto o más importante que la técnica utilizada para disminuir las complicaciones.(AU)

OBJECTIVES: Provide evidence based guidelines for tracheostomy in critically ill adult patients and identify areas needing further research. METHODS: A task force composed of representatives of 10 member countries of the Pan-American and Iberic Federation of Societies of Critical and Intensive Therapy Medicine and of the Latin American Critical Care Trial Investigators Network developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: The group identified 23 relevant questions among 87 issues that were initially identified. In the initial search, 333 relevant publications were identified of which 226 publications were chosen. The task force generated a total of 19 recommendations: 10 positive (1B=3, 2C=3, 2D=4) and 9 negative (1B=8, 2C=1). A recommendation was not possible in six questions. CONCLUSION: Percutaneous techniques are associated with a lower risk of infections compared to surgical tracheostomy. Early tracheostomy only seems to reduce the duration of ventilator use but not the incidence of pneumonia, the length of stay, or the long-term mortality rate. The evidence does not support the use of routine bronchoscopy guidance or laryngeal masks during the procedure. Finally, proper prior training is as important or even a more significant factor in reducing complications than the technique used.(AU)

Evidence-based guides in tracheostomy use in critical patients. / Guías basadas en la evidencia para el uso de traqueostomía en el paciente crítico.

OBJECTIVES: Provide evidence based guidelines for tracheostomy in critically ill adult patients and identify areas needing further research. METHODS: A task force composed of representatives of 10 member countries of the Pan-American and Iberic Federation of Societies of Critical and Intensive Therapy Medicine and of the Latin American Critical Care Trial Investigators Network developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: The group identified 23 relevant questions among 87 issues that were initially identified. In the initial search, 333 relevant publications were identified of which 226 publications were chosen. The task force generated a total of 19 recommendations: 10 positive (1B=3, 2C=3, 2D=4) and 9 negative (1B=8, 2C=1). A recommendation was not possible in six questions. CONCLUSION: Percutaneous techniques are associated with a lower risk of infections compared to surgical tracheostomy. Early tracheostomy only seems to reduce the duration of ventilator use but not the incidence of pneumonia, the length of stay, or the long-term mortality rate. The evidence does not support the use of routine bronchoscopy guidance or laryngeal masks during the procedure. Finally, proper prior training is as important or even a more significant factor in reducing complications than the technique used.

Pharmacokinetic study of enrofloxacin in Nile tilapia (Oreochromis niloticus) after a single oral administration in medicated feed.

The objective of this study was to evaluate the disposition kinetics of enrofloxacin (ENR) in the plasma and its distribution in the muscle tissue of Nile tilapia (Oreochromis niloticus) after a single oral dose of 10 mg/kg body weight via medicated feed. The fish were kept at a temperature between 28 and 30 °C. The collection period was between 30 min and 120 h after administration of the drug. The samples were analyzed by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The ENR was slowly absorbed and eliminated from the plasma (Cmax = 1.24 ± 0.37 µg/mL; Tmax = 8 h; T1/2Ke  = 19.36 h). ENR was efficiently distributed in the muscle tissue and reached maximum values (2.17 ± 0.74 µg/g) after 8 h. Its metabolite, ciprofloxacin (CIP), was detected and quantified in the plasma (0.004 ± 0.005 µg/mL) and muscle (0.01 ± 0.011 µg/g) for up to 48 h. After oral administration, the mean concentration of ENR in the plasma was well above the minimum inhibitory concentrations (MIC50 ) for most bacteria already isolated from fish except for Streptococcus spp. This way the dose used in this study allowed for concentrations in the blood to treat the diseases of tilapia.

MDGC-MS analysis of essential oils from Protium heptaphyllum (Aubl. ) and their antifungal activity against Candida specie / Análise MDGC-MS de óleos essenciais de Protium heptaphyllum (Aubl. ) e sua atividade antifúngica contra espécies de Candida

ABSTRACT Protium heptaphyllum is found in the Amazon region, and in various Brazilian states and South American countries. Also Known as almecega, it produces an oil resin used in traditional medicine as analgesic, anti-inflammatory, cicatrizant and expectorant, it is rich in pentacyclic triterpenes and essential oil. The main objective of this study was to analyze the chemical composition of P. heptaphyllumresin (OEPh) over different extraction times and to evaluate their antifungal activity against Candida species, obtained from gardeners with onychomycosis, using the disk diffusion method. The OEPh was obtained by hydrodistillation and analyzed by Multidimensional Gas Chromatography coupled with Mass Spectrometry (MDGC / MS). Candida species were obtained from lesions on the nails of horticulturist from a community garden in the city of Teresina, Piauí, Brazil. The antifungal activity in concentrations of 1000 µg/L, 500 µg/L and 250 µg/L, PROTOCOL M44-A2 (CLSI 2009) OEPh was tested. The main constituents identified were: l-limonene, α-terpineol, p-cineol, o-cymene and α-phellandrene, however, its composition varies significantly with extraction time. All species, except C. rugosa, were inhibited with halo (≥ 14 mm) at 1000 μg / L. C. krusei is naturally resistant to the drug fluconazole, but when tested with OEPh the clinical species (case 9) demonstrated sensitivity in three dilutions (halo ≤ 10 ≥ 14) and the standard strain was inhibited at concentration of 1000 μg/Lg / L (halo 14mm). A similar situation also occurred with the standard strain of C. parapsilosis (halo ≥ 11mm). OEPh has considerable antifungal activity, which merits further investigation for alternative clinical applications, since this species is widely distributed in our community, and it presents good yields, and also has important therapeutic applications.

RESUMO Protium heptaphyllum é encontrada na região amazônica, em vários estados do Brasil e países da América do Sul. Conhecida como almecega produz uma resina oleosa usada na medicina popular como analgésica, antiinflamatória, cicatrizante e expectorante, é rica em triterpenos pentaciclicos e óleo essencial. O objetivo principal do presente trabalho foi analisar a composição química do óleo essencial da resina P. heptaphyllum (OEPh) em diferentes tempo de extração e avaliarsuaatividade antifúngica contra espécies de Candida, isoladas de horticultores com onicomicoses, por método de disco-difusão. O OEPh foi obtido por hidrodestilação, analisado por Cromatografia Gasosa Multidimensinal Acoplada a Espectrometria de Massas (MDGC/MS). As espécies de Candida foram obtidas de lesões nas unhas de horticultores de uma horta comunitária na cidade de Teresina, Piauí, Brasil. Testou-se a atividade antifúngica do OEPhnas concentrações de 1000 μg/L, 500 μg/L e 250 μg/L, protocolo M44-A2 (CLSI 2009). Os principais constituintes identificados foram l- limoneno, α-terpineol, p-cineol, o-cimeno e α-felandreno, entretanto, sua composição varia significativamente em decorrência do tempo de extração. Todas as espécies, exceto a C. rugosa, foram inibidas com halo ( Χ ≥ 14 mm) na concentração de 1000 μg/L. C. krusei é naturalmente resistente ao fármaco fluconazol, mas quando testado com OEPh,a espécie clínico (caso 9) demonstrou sensibilidade nas três diluições (halo Χ ≤ 10 ≥ 14) e a cepa padrão foi inibida na concentração de 1000 μg/L (halo Χ 14mm). Fato semelhante também ocorreu com a cepa padrão de C. parapsilosis (halo Χ ≥ 11mm). O OEPh possui atividade antifúngica considerável, merecendo uma investigação mais aprofundada para aplicações clínicas alternativas, uma vez que esta espécie é amplamente distribuída em nossa comunidade, apresenta bom rendimento e, ainda, aplicações terapêuticas importantes.

Ruthenium carbenes supported on mesoporous silicas as highly active and selective hybrid catalysts for olefin metathesis reactions under continuous flow.

In the search for a highly active and selective heterogenized metathesis catalyst, we systematically varied the pore geometry and size of various silica-based mesoporous (i.e., MCM-41, MCM-48, and SBA-15) and microporous (ZSM-5 and MWW) versus macroporous materials (D11-10 and Aerosil 200), besides other process parameters (temperature, dilution, and mean residence time). The activity and, especially, selectivity of such "linker-free" supports for ruthenium metathesis catalysts were evaluated in the cyclodimerization of cis-cyclooctene to form 1,9-cyclohexadecadiene, a valuable intermediate in the flavor and fragrance industry. The optimized material showed not only exceptionally high selectivity to the valuable product, but also turned out to be a truly heterogeneous catalyst with superior activity relative to the unsupported homogeneous complex.

Linker-free, silica-bound olefin-metathesis catalysts: applications in heterogeneous catalysis.

A set of heterogenized olefin-metathesis catalysts, which consisted of Ru complexes with the H(2)ITap ligand (1,3-bis(2',6'-dimethyl-4'dimethyl aminophenyl)-4,5-dihydroimidazol-2-ylidene) that had been adsorbed onto a silica support, has been prepared. These complexes showed strong binding to the solid support without the need for tethering groups on the complex or functionalized silica. The catalysts were tested in the ring-opening-ring-closing-metathesis (RO-RCM) of cyclooctene (COE) and the self-metathesis of methyl oleate under continuous-flow conditions. The best complexes showed a TON>4000, which surpasses the previously reported materials that were either based on the Grubbs-Hoveyda II complex on silica or on the classical heterogeneous Re(2)O(7)/B(2)O(3) catalyst.

Promoter -817C>T variant of B lymphocyte stimulator gene (BLyS) and susceptibility to endometriosis-related infertility and idiopathic infertility in Brazilian population.

Many theories have been proposed to explain the development of endometriosis, and recently, autoimmune aetiology has been suggested. Besides, it is well known that endometriosis, especially the advanced disease, may impair fertility. B lymphocyte stimulator (BLyS) is a cytokine produced by macrophages and is necessary for normal B cell development. One of the most studied polymorphisms is the -817C/T in the promoter region of the gene. We aimed to assess the association between endometriosis-related infertility and idiopathic infertility and the BLyS -817C/T polymorphism in a Brazilian population. We performed a case-control study comprising 165 infertile women with endometriosis, 83 with idiopathic infertility and 145 fertile and assessed the association with BLys -817C/T polymorphism. BLyS -817C/T polymorphism was detected using TaqMan PCR. The results were analysed statistically, and a P-value < 0.05 was considered significant. The results disclosed similar genotype and allelic frequencies between endometriosis-related infertility (P = 0.225) and control group, regardless of the disease stage (P = 0.213 and P = 0.462, respectively). However, a statistically significant difference was observed regarding idiopathic infertile group (P = 0.048) compared with controls. Considering the dominant and recessive inheritance models, no significant differences in both endometriosis and idiopathic infertility group were found. The genotype frequencies were in Hardy-Weinberg equilibrium in all studied groups. The results point to a possible association between BLyS -817C/T polymorphism and idiopathic infertility in Brazilian population.

Multi-quantum echoes in GdAl2 zero-field high-resolution NMR.

In this paper we present a series of high-resolution zero-field NMR spectra of the polycrystalline intermetallic compound GdAl(2). The spectra were obtained with the sample at 4.2K in the ordered magnetic state and in the absence of an external static magnetic field. Using a sequence composed of two RF pulses, we obtained up to five multi-quantum echoes for the (27)Al nuclei, which were used to construct the zero-field NMR spectra. The spectra obtained from the FID observed after the second pulse and the even echoes exhibited higher resolution than the odd ones. In order to explain such behavior, we propose a model in which there are two regions inside the sample with different inhomogeneous spectral-line broadenings. Moreover, with the enhanced resolution from the FID signal, we were able to determine quadrupolar couplings with great precision directly from the respective spectra. These results were compared with those obtained from the quadrupolar oscillations of the echo signals, and showed good agreement. Similar data were also obtained from (155)Gd and (157)Gd nuclei.

Analysis of CTLA4 gene variant in infertile Brazilian women with and without endometriosis.

An autoimmune aetiology has been suggested for endometriosis mostly on the basis of an increased prevalence of autoimmune diseases in affected women. Cytotoxic T lymphocyte antigen (CTLA) 4 gene is recognized as a primary determinant for autoimmunity, since specific polymorphisms have been associated with predisposition to most autoimmune disorders. Thus, the objective of the study was to evaluate CTLA4 polymorphism (+49A/G) in a group of infertile women with and without endometriosis and controls. Case-control study comprising 244 infertile women (177 with endometriosis and 67 without endometriosis) and 172 fertile women as controls. CTLA4 polymorphism was identified by qPCR. The results were analysed statistically and a P-value <0.05 was considered significant. We found relatively similar CTLA4 polymorphisms genotype frequencies in women with and without endometriosis and controls (P=0.158 and P=0.262, respectively). When the patients with minimal/mild endometriosis and moderate/severe endometriosis were studied separately, no difference was also found related to controls (P=0.560 and P=0.11, respectively). The data suggest that the CTLA4 polymorphism is not associated with endometriosis and/or infertility in Brazilian women.

Soropositividade e lesões sugestivas de brucelose em bovinos abatidos no estado de Tocantins, Brasil / Serumpositivity and lesions suggestive of brucellosis in cattle slaughtered in Tocantins state, Brazil

De outubro a dezembro de 2007, 845 amostras de sangue foram coletadas de 836 vacas (98,9%) e nove touros (1,1%), em um matadouro com inspeção federal no Estado do Tocantins. Cento e quarenta e duas amostras [(16,8%) IC 95% 14,3-19,4] tiveram reação positiva ao teste do antígeno acidificado e tamponado de Brucella abortus. Um touro foi positivo ao teste. Quinhentos e sessenta e um bovinos (66,3%) procederam do Estado do Pará e 284 (33,7%) do Estado do Tocantins. A prevalência de soropositividade foi de 17,2% [IC (95%) 13,6 - 19,9] e de 16,6% [IC (95%) 13,0 - 22,2] para o gado do Pará e Tocantins, respectivamente. Estas prevalências não são significativamente diferentes (p > 0,05). Nenhuma das vacas tinha registro de vacinação contra brucelose. Os exames "ante e post-mortem" não detectaram qualquer sinal ou lesão sugestiva à brucelose, como descargas vaginais, orquites, artrites ou bursites [(0,00%) IC 95% 0,00-0,43] em todos os bovinos da amostra. Esta situação, associada às altas prevalências da doença e à falta de diagnóstico da brucelose nos rebanhos, aumenta o número de bovinos infectados abatidos sob condições sanitárias inadequadas, o risco de contaminação dos trabalhadores e a colocação no mercado, sem restrição, de carne de animais infectados.

From October to December 2007, 845 blood samples were collected from 836 cows (98.9%) and nine bulls (1.1%), in a slaughterhouse with federal inspection in the state of Tocantins. One hundred and forty-two samples [(16.8%) 95% CI 14.3-19.4] had positive reaction to the plate agglutination test carried out with acidified and buffered antigen of Brucella abortus. One bull was positive to the test. Five hundred and sixty one bovines came from the State of Pará (66.3%) and 284 (33.7%) came from the State of Tocantins. The prevalence of serum positivity was 17.2% [CI (95%) 13.6 ­ 19.9] and 16.6% [CI (95%) 13.0 ­ 22.2] for cattle came from Pará and Tocantins, respectively, with no significant difference between these frequencies (p > 0.05). None of the cows had record of vaccination against brucellosis. "Ante and post-mortem" examinations could not find any sign or lesion attributable to brucellosis, such as vaginal discharges, joint inflammation or bursitis [(0.00%) 95% CI 0.00-0.43] in all bovines sampled. This situation, coupled with the high prevalence of the disease and the lack of brucellosis diagnostic at herds, increases the number of infected cattle slaughtered under inadequate sanitary conditions, the risk of contamination of workers and placing on the market, without restriction, the meat from infected animals.

NMR quadrupolar system described as Bose-Einstein-condensate-like system.

This paper presents a description of nuclear magnetic resonance (NMR) of quadrupolar systems using the Holstein-Primakoff (HP) formalism and its analogy with a Bose-Einstein condensate (BEC) system. Two nuclear spin systems constituted of quadrupolar nuclei I=3/2 ((23)Na) and I=7/2 ((133)Cs) in lyotropic liquid crystals were used for experimental demonstrations. Specifically, we derived the conditions necessary for accomplishing the analogy, executed the proper experiments, and compared with quantum mechanical prediction for a Bose system. The NMR description in the HP representation could be applied in the future as a workbench for BEC-like systems, where the statistical properties may be obtained using the intermediate statistic, first established by Gentile. The description can be applied for any quadrupolar systems, including new developed solid-state NMR GaAS nanodevices.

A study of the relaxation dynamics in a quadrupolar NMR system using Quantum State Tomography.

This article reports a relaxation study in an oriented system containing spin 3/2 nuclei using quantum state tomography (QST). The use of QST allowed evaluating the time evolution of all density matrix elements starting from several initial states. Using an appropriated treatment based on the Redfield theory, the relaxation rate of each density matrix element was measured and the reduced spectral densities that describe the system relaxation were determined. All the experimental data could be well described assuming pure quadrupolar relaxation and reduced spectral densities corresponding to a superposition of slow and fast motions. The data were also analyzed in the context of Quantum Information Processing, where the coherence loss of each qubit of the system was determined using the partial trace operation.

Quantum state tomography for quadrupolar nuclei using global rotations of the spin system.

In this paper, we describe a quantum state tomography method based on global rotations of the spin system which, together with a coherence selection scheme, enables the complete density matrix reconstruction. The main advantage of this technique, in respect to previous proposals, is the use of much shorter rf pulses, which decreases significantly the time necessary for algorithm quantum state tomography. In this case, under adequate experimental conditions, the rf pulses correspond to simple spatial rotations of the spin states, and its analytical description is conveniently given in the irreducible tensor formalism. Simulated results show the feasibility of the method for a single spin 72 nucleus. As an experimental result, we exemplify the application of this method by tomographing the steps during the implementation of the Deutsch algorithm. The algorithm was implemented in a (23)Na quadrupole nucleus using the strongly modulated pulses technique. We also extended the tomography method for a 3-coupled homonuclear spin 12 system, where an additional evolution under the internal Hamiltonian is necessary for zero order coherences evaluation.