Heterocyclic terpenes: linear furano- and pyrroloterpenoids

The emphasis of this review is on linear furano- and pyrroloterpenoids, together with their relevant biological activities, source organisms and country of origin. First total syntheses that lead to the revision of structures or stereochemistries have been included, and 206 references are cited

ESTUDO DE IMPACTE AMBIENTAL DO ALQUEVA - CLIMA

A circulação atmosférica é fortemente influenciada pela superfície da Terra, reflectindo a estrutura espacial da orografia, das massas de água e da cobertura do solo. As heterogeneidades observadas na superfície do planeta são uma das razões da existência de energia disponível, a partir da qual se pode manter um ciclo de conversões de Energia e Entropia, que estão na base da circulação observada. Não quer isto dizer, no entanto, que qualquer alteração significativa e permanente da superfície se traduza necessariamente numa correspondente alteração climática. Na verdade, existem certos condicionamentos dinâmicos que favorecem o efeito das grandes e médias escalas horizontais, de tal modo que uma alteração intensa mas localizada no espaço pode ter um efeito desprezável, enquanto uma outra alteração mais ténue mas extensa pode ser muito mais significativa. O conceito de escala tem por isso um papel central na Meteorologia. Convencionalmente fala-se em quatro escalas distintas na dinâmica da Atmosfera - a Escala Planetária (dezenas de milhares de km), a Escala Sinóptica (milhares de km), a Mesoscala (dezenas de km) e a Microscala - verificando-se que as duas escalas intermédias têm um papel fundamental na definição do clima observado em cada local. Na latitude de Portugal, em particular, observa-se que os regimes de circulação médios e a precipitação são em grande medida condicionados pela escala sinóptica, especialmente no período de Inverno, em que ocorre a maior parte da precipitação sob a forma de precipitação frontal. No entanto é também bem conhecida a influência de circulações de mesoscala no estabelecimento de diferenciação climática entre locais relativamente próximos. Por outro lado, o valor local de diversos parâmetros atmosféricos é muitas vezes fortemente condicionado por condições que ocorrem numa escala horizontal ainda mais pequena, influenciando por exemplo a exposição ao Sol ou ao Vento com consequências, por vezes significativas, em termos de Temperatura. O empreendimento do Alqueva, dada a natureza das alterações introduzidas e a sua extensão horizontal, implicará com certeza alterações microclimáticas e poderá implicar alterações na circulação de mesoscala da região envolvente. Na verdade, é aparentemente um dos poucos empreendimentos localizados capaz de ter efeito à escala regional, em termos climáticos

A note on the tensor and vector exchange contributions to KKˉ→KKˉ,DDˉ→DDˉK \bar K \to K \bar K, D \bar D \to D \bar D and π+π−→π+π−\pi^+ \pi^-\to \pi^+ \pi^- reactions

In this note we study the tensor and vector exchange contributions to the elastic reactions involving the pseudoscalars mesons $\pi^+ \pi^-$, $K^{+}K^{-}$ and $D^{+}D^{-}$. In the case of the tensor-exchange contributions we assume that an intermediate tensor $f_2(1270)$ is dynamically generated from the interaction of two virtual $\rho$ mesons, with the use of a pole approximation. The calculation of the two-loop amplitude is facilitated since the triangle loops can be factorized and computed separately. The results show very small contributions coming from the tensor-exchange mechanisms when compared with those from the vector-exchange processes.Comment: 8 pages, 5 figure

B+B^+ decay to K+ηηK^+\eta\eta with (ηη\eta\eta) from the DDˉ(3720)D\bar{D}(3720) bound state

We search for a $B$ decay mode where one can find a peak for a $D \bar{D}$ bound state predicted in effective theories and in Lattice QCD calculations, which has also been claimed from some reactions that show an accumulated strength in $D \bar{D}$ production at threshold. We find a good candidate in the $B^+\to K^+ \eta\eta$ reaction, by looking at the $\eta\eta$ mass distribution. The reaction proceeds via a first step in which one has the $B^+\to D_s^{*+} \bar{D}^0$ reaction followed by $D_s^{*+}$ decay to $D^0 K^+$ and a posterior fusion of $D^0 \bar{D}^0$ to $\eta \eta$, implemented trough a triangle diagram that allows the $D^0 \bar{D}^0$ to be virtual and produce the bound state. The choice of $\eta\eta$ to see the peak is based on results of calculations that find the $\eta\eta$ among the light pseudoscalar channels with stronger coupling to the $D \bar{D}$ bound state. We find a neat peak around the predicted mass of that state in the $\eta\eta$ mass distribution, with an integrated branching ratio for $B^+\to K^+$ ($D\bar{D}$, bound) ; ($D\bar{D}$, bound) $\to \eta \eta$ of the order of $1.5 \times 10^{-4}$, a large number for hadronic $B$ decays, which should motivate its experimental search

A new polyhalogenated epoxymonoterpene from Plocamium cartilagineum

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Lipidomic signatures reveal seasonal shifts on the relative abundance of high-valued lipids from the brown algae Fucus vesiculosus

Fucus vesiculosus is an edible brown macroalga, with health benefits associated with its consumption and also a source of bioactive molecules. It is acknowledged that the biochemical composition of macroalgae changes when exposed to different environmental conditions occurring on different habitats, such as the water temperature, and light intensity. In the present study, the polar lipidome of Fucus vesiculosus was characterized for the first time using modern high-resolution HILIC-MS, and MS/MS approaches, to evaluate the phenotypic variability in two seasons of the year, e.g., winter and spring. A total of 187 molecular species were identified over eighteen classes of glycolipids, phospholipids and betaine lipids. Principal component analysis (PCA) multivariate statistical analysis and cluster analysis of polar lipid classes, polar lipid species and total fatty acids (FA) datasets, showed clustering according to the seasonal groups. While the lipid profile of Fucus vesiculosus harvested in the winter and spring yielded the same molecular species, the relative abundance of these species was significantly different. In the winter, changes were mainly due to the increased relative abundance of some molecular species of glycolipids and phospholipids, bearing octadeca(poly)enoic (18:3, 18:4) and eicosa(poly)enoic (20:4, 20:5) FA and betaine lipids species with short saturated FA (14:0) and polyunsaturated FA (PUFA). Importantly, glycolipids with n-3 PUFA and sulfolipids, have been reported to have important biological activities and therapeutic value. Overall, Fucus vesiculosus is a promising source of bioactive compounds that can be used as functional food or ingredients for human nutrition, feed, pharma, and cosmetic formulations. In this study, samples harvested in the winter season maximized yields of these bioactive components, when compared with samples harvested in the spring.publishe

Differential Quercus spp pollen-particulate matter interaction is dependent on geographical areas

Particulate matter (PM) and pollen interaction, either airborne or at the respiratory mucosa needs further clarification, as allergic reaction intensification can be related to the PM physical characteristics and toxicity. This study aimed to investigate the physical-chemical properties of PM that can adhere to the pollen wall during its transport or inhalation, using Quercus spp. as a model, in three Portuguese cities with different geographical locations, meteorological influence and urbanization levels. Possible sources were evaluated through air masses trajectory analysis using the HYSPLIT model and correlation with meteorological factors. The sampling was performed using a 7-days Hirst-type volumetric sampler, and the pollen grains were observed using a Field Emission Electron Probe Microanalyser for PM analysis. A secondary electron image of each pollen grain was taken, to determine the adhered particles characteristics and energy dispersive x-ray spectroscopy (EDS) spectra were obtained for individual particles. A total of 484 pollen grains was observed, with 7683 particles counted and 1914 EDS spectra analyzed. The particle's equivalent diameter ranged from 0.3-16 μm, with most having a diameter < 3 μm. For the three cities, there were significant differences in the number of particles per pollen and the % area occupied by the particles. Particles adhered were mainly Si-rich, but variations in other dominant groups were observed. For Évora and Guarda, Ca-rich, SO-rich were second and third more representative, while Porto were Organic and Cl-rich. Metals&Oxides were found in all cities with the highest number in Porto. P-rich particles were only found in Évora. Sea salt particles were observed in Évora, coincide with air mass trajectories possible carrying them from the Mediterranean Sea. In conclusion, the PM physical characteristics are similar between the studied cities, however, the dominant chemical composition is different, certainly impacting the exposome influence and pollen-allergy intensification towards the same pollen type and concentration

El golpe de ariete en tuberías de impulsión. Comentarios a las expresiones de Mendiluce

[ES] El dimensionado de las tuberías de impulsión es un problema clásico dentro del campo de la Ingeniería del Agua. Debido a la complejidad de las ecuaciones que gobiernan la transmisión de las perturbaciones que se generan como consecuencia de la parada del grupo impulsor motor-bomba en el contexto del modelo elástico, conocido coloquialmente como golpe de ariete, el uso de expresiones y fórmulas simplificadas de cálculo han gozado de gran predicamento. En la Península Ibérica han destacado, de entre todas ellas, las debidas a Mendiluce. El presente artículo revisa el problema del cálculo de las sobrepresiones por parada del grupo motor-bomba en tuberías de impulsión, establece las diferencias entre los modelos de análisis de los transitorios rápidos (modelo rígido u oscilación en masa y modelo elástico o golpe de ariete), delimita los campos de validez de cada uno de ellos para esta aplicación concreta, sitúa las fórmulas de Mendiluce en su contexto real y presenta unas gráficas para un primer cálculo de impulsiones que pueden ser de gran utilidad en un buen número de aplicaciones. Finalmente se presentan una serie de ejemplos que permiten reforzar las conclusiones establecidas.Abreu, JM.; Cabrera, E.; Iglesias, PL.; Izquierdo, J. (1995). El golpe de ariete en tuberías de impulsión. Comentarios a las expresiones de Mendiluce. Ingeniería del Agua. 2(2):37-52. https://doi.org/10.4995/ia.1995.2676SWORD375222Abreu, J.M.; Cabrera, E.; Izquierdo, J.; García-Serra, J., (1995a), "Flow Modelling in pressurized systems. From water hammer to steady state. I: Fundamentals", Remitido al Journal of Hydraulics Engineering, ASCE.Abreu, J.M.; Cabrera, E.; Izquierdo, J.; García-Serra, J., (1995b), "Flow Modelling in pressurized systems. From water hammer to steady state. II: Examples", Remitido al Journal of Hydraulics Engineering, ASCE.Abreu, J.M.; Guarga, R.; Izquierdo, J. Editores, (1995c), Transitorios y oscilaciones en sistemas hidráulicos a presión. Ed. U.D. Mecánica de Fluidos. Universidad Politécnica de Valencia.Allievi, L., (1903), "Teoría genérale del moto pertúrbalo dell'aqua nei tubi in pressione". Ann. Soc. Ing. Arch. Italiana.Bergeron. L., (1950), Du coup de belier en hydraulique an coup du foudre en electricite. Ed. Dunod, Paris.Betamio de Almeida, A., (1981), O golpe de ariete en condutas elevatorias. Sintese dos conhocimentos actuáis. Memorias do L.N.E.C. n° 550, Lisboa.Betamio de Almeida, A., (1989), Transientes hidráulicos en condutos forzados. Congreso Internacional sobre casos e accidentes em sistemas fluidos, Sao Paulo.Betamio de Almeida, A., (1990), Protecçao contra o golpe de ariete. Publicación interna del Instituto Superior Técnico, Lisboa.Betamio de Almeida, A.; Koelle, E., (1992), Fluid transients in pipe networks. Ed Computational Mechanics Publications, Southampton.Cabrera, E.; Martínez, F., (1978), Cálculo del diámetro más económico en tuberías de presión. Ingeniería Química. Marzo. 1978, pp. 71-78.Cabrera, E.; García-Serra, J.; Iglesias, P.L., (1995), Flow Modelling in water distribution networks. From water hammer to steady-state. Primera lección del Curso Internacional "Improving efficiency and reliability in water distribution systems". Kluwer Academic Publishers, Dordretch.Chaudhry, H., (1987), Applied hydraulic transients. Van Nostrand Reinhold Company Inc, New York.De Martino, G., (1973), Sul calcolo del GD2 negli impianti di sollevamento. L'Energia Elettrica, n° 8, pp. 487-500.Donsky, B., (1961), Complete pump characteristics and the effect of specific speeds in hydraulic transients. Journal Basic Engineering. ASME. Diciembre, pp. 685-699.Donsky, B.; Byrne, R.; Barlett, P., (1979), Upsurge and speed-rise charts due to pump shut-down. journal of the Hydraulics Division. ASCE. Junio, pp. 661-674.Joukowsky. N.E., (1898), Mem. Imperial Academy Soc. of St. Petersburg. Vol 9, n°5.Kinno, H.; Kennedy, J.F., (1965), Water-hammer charts for centrifugal pump systems. Journal of the Hydraulic Division. ASCE. Mayo, pp. 247-270.Knapp, R.T., (1937), Complete characteristics of centrifugal pumps and their use in the prediction of transient behaviour. Transactions ASME, vol 59, Noviembre.Marchal, M.; Flesh, G.; Suter, P., (1965), The calculation of waterhammer problems by means of digital computer. Proc. International Symposium on Waterhammer in pumped storage projects. ASME, pp. 168-188.Mendiluce, E. a), (1965), Investigación teórico-práctica de los valores reales del golpe de ariete por parada brusca del grupo motor bomba en impulsiones. Dyna, 1965, n° 3, pp. 155-170 y n° 4, pp. 205-215.Mendiluce, E., (1987), El golpe de ariete en impulsiones. Librería Editorial Bellisco. Madrid.Michaud, J., (1878), Coups de bélier dans les conduites. Etude des moyens employes pour en attenuer les effects. Bulletin de la Societé Vandoise des Inginers et des Architectes. Laussane, 4c anné. nos 3 y 4, septiembre y octubre, pp. 56-64 y 65-77.Parmakian, J., (1955), Waterhammer analysis. Prentice Hall Inc. New York.Streeter, V.L.; Wylie, E.B., (1967), Hydraulic Transients. Mc Graw Hill Book Co. Inc. New York.Symposium on Waterhammer, (1933), ASME y ASCE. New York.Thorley, A.R.D., (1991), Fluid Transients in pipeline systems. D&L George LTD. Herts. England.U.D. Mecánica de Fluidos, (1993), DYAGATS. Diseño y análisis de golpe de ariete en tuberías simples. Manual del usuario. Universidad Politécnica de Valencia.Wylie, E.B.; Streeter, V.L., (1993), Fluid transients in systems. Prentice Hall. Englewood Cliffs. New Yor

Photocatalytic activity of TiO2/graphene and TiO2/graphene oxide nanocomposites

Semiconductor-based heterogeneous photocatalysis has been one of the most promising processes for the treatment of contaminated water. Among the available catalysts, titanium dioxide (TiO2) presents the best photocatalytic properties, being chemically and biologically inert, stable, non-toxic, cheap and easy to produce. However, its energy bang gap lies in the ultraviolet (UV) range, which is responsible for a reduced spectral activation, since UV radiation corresponds to only 5% of the solar spectrum [1]. For this reason, one of the main purposes of the scientific community has been to improve the photocatalytic performance of TiO2, namely through an adequate doping of this material, or through the creation of nanocomposites, to enable photocatalysis occurrence by the incidence of visible light. One alternative concerns the application of nanocomposites of TiO2 with graphene and graphene oxide to photocatalytic processes [2]. In this work, nanocomposites of TiO2 with different weight concentrations of graphene and graphene oxide (namely 0.5%, 1%, 1.5% and 3%) were synthetized by a one-step hydrothermal method and characterized in terms of morphology, crystalline structure, vibrational modes and optical band gap. The photocatalytic activity of these nanocomposites was then evaluated through the degradation of methylene blue and ciprofloxacin solutions under UV and visible radiation. The results indicated that the studied nanocomposites presented higher degradation rates of the methylene blue than the pure TiO2, which increased with the content of graphene/graphene oxide. However, these composites proved to be less suitable to degrade the ciprofloxacin solution than the pure TiO2 nanoparticles.Portuguese Foundation for Science and Technology (FCT) - UID/FIS/04650/2013, PTDC/CTM-ENE/5387/2014 and SFRH/BD/98616/2013; Basque Government Industry Department under the ELKARTEK Program.info:eu-repo/semantics/publishedVersio