Unifying thermodynamic and kinetic descriptions of single-molecule processes: RNA unfolding under tension

We use mesoscopic non-equilibrium thermodynamics theory to describe RNA unfolding under tension. The theory introduces reaction coordinates, characterizing a continuum of states for each bond in the molecule. The unfolding considered is so slow that one can assume local equilibrium in the space of the reaction coordinates. In the quasi-stationary limit of high sequential barriers, our theory yields the master equation of a recently proposed sequential-step model. Non-linear switching kinetics is found between open and closed states. Our theory unifies the thermodynamic and kinetic descriptions and offers a systematic procedure to characterize the dynamics of the unfolding processComment: 13 pages, 3 figure

Electronic and phononic properties of the chalcopyrite CuGaS2

The availability of ab initio electronic calculations and the concomitant techniques for deriving the corresponding lattice dynamics have been profusely used for calculating thermodynamic and vibrational properties of semiconductors, as well as their dependence on isotopic masses. The latter have been compared with experimental data for elemental and binary semiconductors with different isotopic compositions. Here we present theoretical and experimental data for several vibronic and thermodynamic properties of CuGa2, a canonical ternary semiconductor of the chalcopyrite family. Among these properties are the lattice parameters, the phonon dispersion relations and densities of states (projected on the Cu, Ga, and S constituents), the specific heat and the volume thermal expansion coefficient. The calculations were performed with the ABINIT and VASP codes within the LDA approximation for exchange and correlation and the results are compared with data obtained on samples with the natural isotope composition for Cu, Ga and S, as well as for isotope enriched samples.Comment: 9 pages, 8 Figures, submitted to Phys. Rev

Effect of Cytisus multiflorus in the control of Type-2 Diabetes

Medicinal plants display diverse pharmacological activities with marked therapeutic effects. Type-2 diabetes (T2D) remains a major health problem among industrialized countries, therefore the investigation of formulas to prevent or attenuate the metabolic syndrome, including new therapeutic agents. Currently the interest of medicinal plants is increasing. Portuguese native flora includes several plants known for their hypoglycemic properties. The aim of this work was to study the pharmacological effect of Cytisus multiflorus, one plant from the Portuguese flora traditionally used as an ethnopharmacological agent in diabetes control

Efeito hipoglicemiante de um extracto aquoso de Cytisus multiflorus

Actualmente o interesse pelas plantas medicinais tem vindo a aumentar pois estas apresentam diversas actividades farmacológicas, entre as quais se inclui o efeito anti-diabético. A flora nativa portuguesa inclui várias plantas às quais se atribuem propriedades hipoglicemiantes, sem que estas tenham, no entanto, sido ainda cientificamente demonstradas. O objectivo deste trabalho foi estudar a possível acção hipoglicemiante de Cytisus Multiflorus, uma planta da flora portuguesa tradicionalmente usada como agente etnofarmacológico no tratamento da diabetes (1). O efeito do extracto aquoso de C. multiflorus foi avaliado em roedores que apresentaram anomalias das curvas de tolerância à glicose oral, seleccionados duma colónia de ratos Wistar. O extracto foi preparado a partir das extremidades florais da planta com água por refluxo durante 10 min. O extracto foi filtrado e seco em evaporador rotativo sob pressão e foi armazenado a 4Cº até posterior administração aos animais. Prepararam-se cinco grupos de cinco fêmeas que foram diariamente administrados, com sonda gástrica, com soro fisiológico (controlo negativo), glicazida (controlo positivo) e três doses diferentes de extracto aquoso da planta (40, 110 e 220mg/Kg), durante 28 dias. As glicemias em jejum e pós-prandiais foram medidas durante o teste. No fim do teste, determinaram-se as insulinemias pós-prandiais e foram avaliados alguns indicadores serológicos e histológicos de toxicidade. Em resposta ao tratamento com o extracto de C. multiflorus, observou-se uma diminuição significativa das glicemias pós-prandeais dependente da dose. O extracto induziu um aumento dependente da dose das insulinemias pós-prandiais. O efeito máximo do extracto de C. multiflorus foi semelhante ao observado em resposta à administração de glicazida. As glicemias em jejum não foram significativamente alteradas. Em conclusão, o extracto aquoso teve um efeito hipoglicemiante, provavelmente devido à estimulação da secreção de insulina, comprovando-se a sua validade como agente etnofarmacológico para o controlo da diabetes tipo 2. Agradecimentos: Este trabalho foi apoiado pelo ICAAM e pelo CNC. Referências: 1. Camejo-Rodrigues J. et al. (2003). J. Ethnopharmacol, 89, 199-209

Advanced tools and techniques to add value to soil stabilization practice

The aim of this paper is to demonstrate the advanced tools and techniques used for adding value to the soil stabilization practice. The tools presented involve advanced laboratory tests and modeling using codes and soft computing to evaluate the mechanical behavior of stabilized soils with cement, ranging from short-term to long-term behavior. More precisely, these tools are able to: 1. Predict the mechanical behavior of the stabilized soils over time from data obtained in the early ages saving time in laboratory tests; 2. Predict the mechanical behavior of the stabilized soils over time based on basic parameters of soil type and binder using historical accurate data, avoiding mechanical laboratory tests. 3. Incorporate the serviceability limit state concept in a novel proposal to estimate the design modulus in function of the uniaxial compressive strength and the strain level, making more economic and sustainable geotechnical solutions.This work was supported by FCT—‘‘Fundação para a Ciência e a Tecnologia’’, within ISISE, project UID/ECI/04029/2013 and through the post doctoral Grant fellowship with reference SFRH/BPD/94792/2013. This work was also partly financed by FEDER funds through the Competitivity Factors Operational Programme—COMPETE and by national funds through FCT within the scope of the project POCI-01-0145-FEDER-007633.info:eu-repo/semantics/publishedVersio

EFFECT OF SEASON ON SERUM COPPER AND ZINC CONCENTRATIONS IN CROSSBRED GOATS HAVING DIFFERENT REPRODUCTIVE STATUS UNDER SEMIARID RANGELAND CONDITIONS IN SOUTHERN MEXICO STATE

The effect of season (rainy: RS, and dry: DS) and reproductive status on copper (Cu) and zinc (Zn) concentrations in blood serum of crossbred goats (BW= 36.01 ± 1.59 kg) were studied under semiarid rangeland conditions in Southern Mexico State. Blood samples from 80 crossbred goats were taken each season (RS and DS). The goats were clustered into 10 different groups considering their reproductive status. Concentrations of Cu and Zn in serum were assayed using atomic absorption. Data were analyzed using a general linear model procedure for a completely randomized design and differences among means were examined using a Tukey test. Blood serum concentrations of Cu and Zn were affected by reproductive status and season (P<0.001). In relation to the season, Cu and Zn serum levels were lower in RS than DS (P<0.05). Overall, kidded goats had the highest values (P<0.01) for Cu than other animals in both seasons (RS or DS). Anestrous goats had the lowest concentrations (P<0.01) for Zn during RS, while all goats at their second or more kidding, rearing single or twins, showed the highest concentrations of Zn (P<0.001) in this season. Adult goats in Southern Mexico State showed a deficiency of Cu and Zn, especially during RS. As such, mineral supplements should be provided with respect to these elements in feeding systems for goats under semiarid rangeland conditions in order to evaluate their impact on health and reproduction

On the nature of long-range contributions to pair interactions between charged colloids in two dimensions

We perform a detailed analysis of solutions of the inverse problem applied to experimentally measured two-dimensional radial distribution functions for highly charged latex dispersions. The experiments are carried out at high colloidal densities and under low-salt conditions. At the highest studied densities, the extracted effective pair potentials contain long-range attractive part. At the same time, we find that for the best distribution functions available the range of stability of the solutions is limited by the nearest neighbour distance between the colloidal particles. Moreover, the measured pair distribution functions can be explained by purely repulsive pair potentials contained in the stable part of the solution.Comment: 6 pages, 5 figure