Coupling biological detection to liquid chromatography

La forma habitual de probar la actividad biológica de una planta dada es a partir de una extracto crudo y, si resultase de interés, continuar con la tediosa y costosa y laboriosas tareas de fraccionamiento, purificación y análisis sistemático de cada fracción resultante. Este procedimiento es actualmente el mismo para mezclas complejas resultantes de métodos sintéticos modernos como la química combinatoria. El procedimiento para la caracterización del fármaco se verá beneficiada si se puede restringir el estudio a solo aquellas fracciones donde la actividad biológica estaba presente.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Pharmacological evaluation of Prosopis ruscifolia extract on lipid profile in hyperglycemic and hyperlipidemic mice

La diabetes es una patología crónica grave, con efectos a largo plazo que incluyen daño a los vasos sanguíneos o dislipidemia diabética. La dislipidemia diabética se caracteriza por el aumento de las concentraciones de triglicéridos de baja densidad y lipoproteínas y una disminución de las lipoproteínas de alta densidad HDL-colesterol (HDL-c). Este estudio tuvo como objetivo evaluar el efecto de Prosopis ruscifolia sobre el perfil lipídico en ratones suizos albinos con hiperglucemia e hiperlipidemia.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Negotiating topic changes:native and non-native English speakers in conversation

There is a tendency to view conversations involving non‐native speakers (NNSs) as inevitably fraught with problems, including an inability to handle topic management. This article, in contrast, will focus on effective topic changes made by non‐native speakers during informal conversations with native speakers of English. A micro‐analysis of ten conversations revealed several ways of shifting conversational topics; however, the article concentrates on those strategies which the participants used to effect a particular type of topic move, namely ‘marked topic changes’, where there is no connection at all with previous talk. The findings show how these topic changes were jointly negotiated, and that the non‐native speakers’ contributions to initiating new topics were competently managed

Diquat Derivatives: Highly Active, Two-Dimensional Nonlinear Optical Chromophores with Potential Redox Switchability

In this article, we present a detailed study of structure−activity relationships in diquaternized 2,2′-bipyridyl (diquat) derivatives. Sixteen new chromophores have been synthesized, with variations in the amino electron donor substituents, π-conjugated bridge, and alkyl diquaternizing unit. Our aim is to combine very large, two-dimensional (2D) quadratic nonlinear optical (NLO) responses with reversible redox chemistry. The chromophores have been characterized as their PF_6^− salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Their visible absorption spectra are dominated by intense π → π^* intramolecular charge-transfer (ICT) bands, and all show two reversible diquat-based reductions. First hyperpolarizabilities β have been measured by using hyper-Rayleigh scattering with an 800 nm laser, and Stark spectroscopy of the ICT bands affords estimated static first hyperpolarizabilities β_0. The directly and indirectly derived β values are large and increase with the extent of π-conjugation and electron donor strength. Extending the quaternizing alkyl linkage always increases the ICT energy and decreases the E_(1/2) values for diquat reduction, but a compensating increase in the ICT intensity prevents significant decreases in Stark-based β_0 responses. Nine single-crystal X-ray structures have also been obtained. Time-dependent density functional theory clarifies the molecular electronic/optical properties, and finite field calculations agree with polarized HRS data in that the NLO responses of the disubstituted species are dominated by ‘off-diagonal’ β_(zyy) components. The most significant findings of these studies are: (i) β_0 values as much as 6 times that of the chromophore in the technologically important material (E)-4′-(dimethylamino)-N-methyl-4-stilbazolium tosylate; (ii) reversible electrochemistry that offers potential for redox-switching of optical properties over multiple states; (iii) strongly 2D NLO responses that may be exploited for novel practical applications; (iv) a new polar material, suitable for bulk NLO behavior

PRODUÇÃO E CARACTERIZAÇÃO FISÍCO-QUÍMICA DE FARINHAS DE MANDARINA VERDE ORGÂNICA (Citrus rediculata)

Para melhorar a qualidade demandarinasdo mercado in natura, a técnica do raleio manual é utilizada pelos citricultores, sendo necessário ralear 60 a 80% dos frutos.Propôs-se elaborar farinhas a partir da casca e da polpa de mandarinas verdes orgânicas oriundas do raleio, caracterizando sua composição proximal a fim de introduzi-las na alimentação humana.As farinhas foram obtidas pela trituração úmida, lavagem, secagem e trituração seca do resíduo desidratado das mandarinas. As análisesdas farinhas de polpa (FP) e de polpa com casca (FPC) de mandarina verde orgânica foram realizadas segundo as metodologias preconizadas pelo Instituto Adolfo Lutz (2008). A umidade (FP=3,78%; FPC=3,03%), cinzas (FP=2,19%; FPC=2,46%) e proteínas (FP=15,83%; FPC=11,38%) das farinhas ficaram dentro do permitido pela legislação brasileira para farinha de trigo comum e/ou integral; apresentaram um teor de fibra bruta alto (FP=18,45%; FPC=17,25%), baixo teor de gorduras (FP=1,25%; FPC=0,85%), boa quantidade de carboidratos (FP=58,14%; FPC=66,25%) e menos calorias (FP=307,25 Kcal/100g; FPC=318,30 Kcal/100g) que a farinha de trigo comum. As farinhas de mandarina verde orgânica são uma alternativa para o enriquecimento de produtos de panificação, agregando não só valor nutricional como minimizando o desperdício de resíduos

Evolution of Linear Absorption and Nonlinear Optical Properties in V-Shaped Ruthenium(II)-Based Chromophores

In this article, we describe a series of complexes with electron-rich cis-{Ru^(II)(NH_3)_4}^(2+) centers coordinated to two pyridyl ligands bearing N-methyl/arylpyridinium electron-acceptor groups. These V-shaped dipolar species are new, extended members of a class of chromophores first reported by us (Coe, B. J. et al. J. Am. Chem. Soc. 2005, 127, 4845−4859). They have been isolated as their PF_6− salts and characterized by using various techniques including ^1H NMR and electronic absorption spectroscopies and cyclic voltammetry. Reversible Ru^(III/II) waves show that the new complexes are potentially redox-switchable chromophores. Single crystal X-ray structures have been obtained for four complex salts; three of these crystallize noncentrosymmetrically, but with the individual molecular dipoles aligned largely antiparallel. Very large molecular first hyperpolarizabilities β have been determined by using hyper-Rayleigh scattering (HRS) with an 800 nm laser and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d → π^* metal-to-ligand charge-transfer (MLCT) and π → π^* intraligand charge-transfer (ILCT) bands. The latter measurements afford total nonresonant β_0 responses as high as ca. 600 × 10^(−30) esu. These pseudo-C_(2v) chromophores show two substantial components of the β tensor, β_(zzz) and β_(zyy), although the relative significance of these varies with the physical method applied. According to HRS, β_(zzz) dominates in all cases, whereas the Stark analyses indicate that β_(zyy) is dominant in the shorter chromophores, but β_(zzz) and β_(zyy) are similar for the extended species. In contrast, finite field calculations predict that β_(zyy) is always the major component. Time-dependent density functional theory calculations predict increasing ILCT character for the nominally MLCT transitions and accompanying blue-shifts of the visible absorptions, as the ligand π-systems are extended. Such unusual behavior has also been observed with related 1D complexes (Coe, B. J. et al. J. Am. Chem. Soc. 2004, 126, 3880−3891)

PRODUÇÃO DE UMA FARINHA DE ALBEDO DE LARANJA COMO FORMA DE APROVEITAMENTO DE RESÍDUO

O Brasil é um dos maiores produtores de suco de laranja e exporta cerca de 70% da sua produção. Durante o processamento do suco de laranja são gerados subprodutos, como o bagaço denominado também de albedo. Visando a diversificação tecnológica, este trabalho possui como objetivo a elaboração de uma farinha a partir de um subproduto da indústria de sucos, que possa ser utilizada como enriquecimento nutricional em formulações de produtos de panificação. A farinha foi obtida pela trituração úmida, lavagem, secagem e trituração seca do resíduo desidratado das laranjas. As análises físico-químicas da farinha de albedo de laranja foram realizadas segundo as metodologias preconizadas pelo Instituto Adolfo Lutz (2008). A umidade (11,75%) da farinha ficou dentro do máximo permitido pela legislação brasileira; apresentou um baixo teor de gorduras (0,42%) e calorias em torno de 18% a menos que a farinha de trigo. A fibra bruta da farinha de albedo da laranja (16,20%) é cinco vezes maior, em comparação a uma farinha tradicional de trigo (3,2%), podendo ser considerada um ingrediente funcional. A farinha de albedo de laranja é uma excelente alternativa para enriquecimento de produtos de panificação, agregando não só valor econômico como valor nutricional, com considerável teor de fibras

Inferring fish escape behaviour in trawls based on catch comparison data: Model development and evaluation based on data from Skagerrak, Denmark

During the fishing process, fish react to a trawl with a series of behaviours that often are species and size specific. Thus, a thorough understanding of fish behaviour in relation to fishing gear and a scientific understanding of the ability of different gear designs to utilize or stimulate various behavioural patterns during the catching process are essential for developing more efficient, selective, and environmentally friendly trawls. Although many behavioural studies using optical and acoustic observation systems have been conducted, harsh observation conditions on the fishing grounds often hamper the ability to directly observe fish behaviour in relation to fishing gear. As an alternative to optical and acoustic methods, we developed and applied a new mathematical model to catch data to extract detailed and quantitative information about species- and size-dependent escape behaviour in towed fishing gear such as trawls. We used catch comparison data collected with a twin trawl setup; the only difference between the two trawls was that a 12 m long upper section was replaced with 800 mm diamond meshes in one of them. We investigated the length-based escape behaviour of cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), witch flounder (Glyptocephalus cynoglossus), and lemon sole (Microstomus kitt) and quantified the extent to which behavioural responses set limits for the large mesh panel's selective efficiency. Around 85% of saithe, 80% of haddock, 44% of witch flounder, 55% of lemon sole, and 55% of cod (below 68 cm) contacted the large mesh panel and escaped. We also demonstrated the need to account for potential selectivity in the trawl body, as it can bias the assessment of length-based escape behaviour. Our indirect assessment of fish behaviour was in agreement with the direct observations made for the same species in a similar section of the trawl body reported in the literature