Vertex results for the robust analysis of uncertain biochemical systems

We consider the problem of assessing the sensitivity of uncertain biochemical systems in the presence of input perturbations (either constant or periodic) around a stable steady state. In particular, we propose approaches for the robust sensitivity analysis of systems with uncertain parameters assumed to take values in a hyper-rectangle. We highlight vertex results, which allow us to check whether a property is satisfied for all parameter choices in the hyper-rectangle by simply checking whether it is satisfied for all parameter choices at the vertices of the hyper-rectangle. We show that, for a vast class of systems, including (bio)chemical reaction networks with mass-action kinetics, the system Jacobian has a totally multiaffine structure (namely, all minors of the Jacobian matrix are multiaffine functions of the uncertain parameters), which can be exploited to obtain several vertex results. We consider different problems: robust non-singularity; robust stability of the steady-state; robust steady-state sensitivity analysis, in the case of constant perturbations; robust frequency-response sensitivity analysis, in the presence of periodic perturbations; and robust adaptation analysis. The developed theory is then applied to gain insight into some examples of uncertain biochemical systems, including the incoherent feed-forward loop, the coherent feed-forward loop, the Brusselator oscillator and the Goldbeter oscillator

Caracterização físicoquímica do mosto e do vinho de uvas Moscato Giallo cultivadas sob cobertura plástica.

O objetivo deste trabalho foi avaliar o efeito da cobertura plástica sobre o mosto e a qualidade do vinho da cultivar Moscato Giallo.bitstream/CNPUV-2009-09/10530/1/cot091.pd

The transcriptional regulator ZNF398 mediates pluripotency and epithelial character downstream of TGF-beta in human PSCs

Human pluripotent stem cells (hPSCs) have the capacity to give rise to all differentiated cells of the adult. TGF-beta is used routinely for expansion of conventional hPSCs as flat epithelial colonies expressing the transcription factors POU5F1/OCT4, NANOG, SOX2. Here we report a global analysis of the transcriptional programme controlled by TGF-beta followed by an unbiased gain-of-function screening in multiple hPSC lines to identify factors mediating TGF-beta activity. We identify a quartet of transcriptional regulators promoting hPSC self-renewal including ZNF398, a human-specific mediator of pluripotency and epithelial character in hPSCs. Mechanistically, ZNF398 binds active promoters and enhancers together with SMAD3 and the histone acetyltransferase EP300, enabling transcription of TGF-beta targets. In the context of somatic cell reprogramming, inhibition of ZNF398 abolishes activation of pluripotency and epithelial genes and colony formation. Our findings have clear implications for the generation of bona fide hPSCs for regenerative medicine

Cobertura plástica: contribuição para a melhoria da qualidade dos vinhos?

A sanidade das uvas é um aspecto importante na definição da qualidade dos vinhos. Esta é relevante por que algumas doenças fúngicas, além de prejudicarem a produção das uvas propriamente dita, afetam a qualidade do vinho, durante o processo de vinificação e no produto final, acentuando odores indesejáveis e acéticoso Uvas com Botrytis cinerea, por exemplo, contêm tirosinases e lacases, que são enzimas responsáveis pela oxidação enzimática dos compostos fenólicos, prejudicando a cor, o aroma e o sabor dos vinhos.bitstream/item/200268/1/9329-2008-p.17-18.pd

Efeito da cobertura plástica na composição de vinhos Moscato Giallo.

A utilização da cobertura plástica impermeável sobre as linhas de cultivo para a produção de uvas destinadas à vinificação é bastante incipiente. Deste modo, há poucas informações a respeito da influência desta tecnologia sobre a qualidade enológIca dos vinhos.Resumo

Do a Few Weeks Matter? Late Preterm Infants and Breastfeeding Issues

The late preterm infant population is increasing globally. Many studies show that late preterm infants are at risk of experiencing challenges common to premature babies, with breastfeeding issues being one of the most common. In this study, we investigated factors and variables that could interfere with breastfeeding initiation and duration in this population. We conducted a prospective observational study, in which we administered questionnaires on breastfeeding variables and habits to mothers of late preterm infants who were delivered in the well-baby nursery of our hospital and followed up for three months after delivery. We enrolled 149 mothers and 189 neonates, including 40 pairs of twins. Our findings showed that late preterm infants had a low rate of breastfeeding initiation and early breastfeeding discontinuation at 15, 40 and 90 days of life. The mothers with higher educational levels and previous positive breastfeeding experience had a longer breastfeeding duration. The negative factors for breastfeeding were the following: Advanced maternal age, Italian ethnicity, the feeling of reduced milk supply and having twins. This study underlines the importance of considering these variables in the promotion and protection of breastfeeding in this vulnerable population, thus offering mothers tailored support

Physicochemical characterization of must and wine Moscato Giallo from grapevines grown under plastic overhead cover

O objetivo deste trabalho foi avaliar a influência da cobertura de plástico sobre as características físico-químicas do mosto e do vinho da cultivar Moscato Giallo. Na safra 2006, um experimento em delineamento completamente casualizado foi realizado em vinhedo com cobertura de plástico impermeável, e sem cobertura como controle. De cada vinhedo, três microvinificações (20 L) foram elaboradas. Foram realizadas avaliações físico-químicas quanto ao: mosto – oBrix, açúcares redutores, densidade, acidez total, ácido tartárico, ácido málico e pH; e vinho – densidade, graduação alcoólica, acidez total, acidez volátil, pH, extrato seco, açúcares redutores, cinzas, I 420, compostos voláteis e minerais. O mosto das videiras cobertas apresentou maior rendimento, porém, menor concentração de açúcares pelo fato de a maturação das uvas ter-se atrasado. Como conseqüência, os vinhos do cultivo protegido tiveram menor graduação alcoólica, embora tenham sido beneficiados pela sanidade das uvas, com a redução de acetato de etila e acidez volátil. O microclima da cobertura também restringiu a concentração de alguns minerais no vinho, principalmente P e K. A cobertura beneficiou a qualidade enológica, porém requer atraso na data de colheita, para as uvas atingirem adequada maturação fisiológica e tecnológica.The objective of this work was to evaluate the plastic overhead cover (POC) effect on must and wine composition of the cultivar Moscato Giallo. In 2006 vintage, it was performed a completely randomly designed experiment, in a vineyard covered with an impermeable plastic cloth, and without covering as control. From each vineyard, three microvinification (20 L) were elaborated. Physico-chemical analysis were performed for: musts – oBrix, reducer sugar contents, density, total acidity, tartaric acid, malic acid and pH; and wines – density, alcohol degree, acidity, volatile acidity, pH, dry extract, reducer sugar contents, ashes, I 420, volatile compounds and minerals. The must of the covered vineyard presented higher yield, but lower sugar content, due to delay on ripening. As consequence, the POC wines showed lower alcohol degree, but with the benefit of a lower ethyl-acetate and volatile acidity levels. The POC microclimate also caused a decrease of some minerals (mainly P and K) in the wines. POC improved the enological quality, however, this demands delay in the harvest date to achieve the adequate physiological and technological maturation of grapes

Predicting adaptation for uncertain systems with robust real plots

In systems biology, perfect adaptation (adaptation) denotes the property of a system reacting to a step input stimulus by completely (partially) restoring the pre-stimulus output value at steady state. We address the problem of predicting adaptation for uncertain dynamical systems. To this aim, we introduce a formal definition of adaptation tailored to the robust analysis of dynamical systems. Whilst the definition is more general and valid also for the step response analysis of nonlinear systems, in the linear case such a definition of adaptation reduces to the presence of a single real zero that dominates all poles. Based on this definition, we can assess robust adaptation by means of the robust real plot, which characterises the position of real zeros and poles for linear systems with parametric uncertainties