Compostos bioativos e atividade antioxidante em cálices de hibísco (Hibiscus sabdariffa L.).

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Effects of hydroxycinnamic acids on the glycolysis pathway

Glycolysis is a metabolic pathway vital to the production of energy and some organisms rely on it solely to meet their energy requirements. It is also a central pathway in the metabolism of carbohydrates and a source of therapeutic targets against diabetes and cancer. Caffeoylquinic acids (CQAs) have been extensively studied for their role in the treatment and prevention of diabetes (and cancer) but their mechanisms of action remain mostly unknown. As such, molecular docking was used to find possible targets of CQAs in the glycolysis pathway. The molecular docking assays showed that CQAs were docked preferably to the Rossman fold (nicotinamide adenine dinucleotide — NAD(H) binding site) of oxidoreductases, that use NAD(H) as a cofactor, than to any other site. In-vitro assays were then performed using two NAD(H) dependent oxidoreductases from glycolysis (alcohol dehydrogenase and L-lactate dehydrogenase) in order confirm if CQAs would compete with the cofactor to inhibit the reaction. The results from these assays indicate that CQAs can act as both inhibitors and activators of NAD(H) dependent oxidoreductases of the glycolysis pathway.info:eu-repo/semantics/publishedVersio

Restoring observed classical behavior of the carbon nanotube field emission enhancement factor from the electronic structure

Experimental Fowler-Nordheim plots taken from orthodoxly behaving carbon nanotube (CNT) field electron emitters are known to be linear. This shows that, for such emitters, there exists a characteristic field enhancement factor (FEF) that is constant for a range of applied voltages and applied macroscopic fields $F_\text{M}$. A constant FEF of this kind can be evaluated for classical CNT emitter models by finite-element and other methods, but (apparently contrary to experiment) several past quantum-mechanical (QM) CNT calculations find FEF-values that vary with $F_\text{M}$. A common feature of most such calculations is that they focus only on deriving the CNT real-charge distributions. Here we report on calculations that use density functional theory (DFT) to derive real-charge distributions, and then use these to generate the related induced-charge distributions and related fields and FEFs. We have analysed three carbon nanostructures involving CNT-like nanoprotrusions of various lengths, and have also simulated geometrically equivalent classical emitter models, using finite-element methods. We find that when the DFT-generated local induced FEFs (LIFEFs) are used, the resulting values are effectively independent of macroscopic field, and behave in the same qualitative manner as the classical FEF-values. Further, there is fair to good quantitative agreement between a characteristic FEF determined classically and the equivalent characteristic LIFEF generated via DFT approaches. Although many issues of detail remain to be explored, this appears to be a significant step forwards in linking classical and QM theories of CNT electrostatics. It also shows clearly that, for ideal CNTs, the known experimental constancy of the FEF value for a range of macroscopic fields can also be found in appropriately developed QM theory.Comment: A slightly revised version has been published - citation below - under a title different from that originally used. The new title is: "Restoring observed classical behavior of the carbon nanotube field emission enhancement factor from the electronic structure

When epigenetics meets bioengineering—A material characteristics and surface topography perspective

The field of tissue engineering and regenerative medicine (TE/RM) involves regeneration of tissues and organs using implantable biomaterials. The term epigenetics refers to changes in gene expression that are not encoded in the DNA sequence, leading to remodeling of the chromatin and activation or inactivation of gene expression. Recently, studies have demonstrated that these modifications are influenced not only by biological cues but also by mechanical and topographical signals. This review highlights the current knowledge on emerging approaches in TE/RM with a focus on the effect of materials and topography on the epigenetic expression pattern in cells with potential impacts on modulating regenerative biology. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2065–2071, 2018.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144628/1/jbmb33953.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144628/2/jbmb33953_am.pd

Species of Neosilba (Diptera: Lonchaeidae) recorded in citrus-producing region in the state of Pará, Brazil.

This work reports on the species of Lonchaeidae obtained from fruits of Citrus sinensis (L.) Osbeck collected in the citrus-producing region of the state of Pará, Brazil. The species registered were Neosilba glaberrima (Wiedemann), N. pendula (Bezzi, 1919) and N. zadolicha McAlpine & Steyskal, 1982

Entanglement of excited states in critical spin chians

Renyi and von Neumann entropies quantifying the amount of entanglement in ground states of critical spin chains are known to satisfy a universal law which is given by the Conformal Field Theory (CFT) describing their scaling regime. This law can be generalized to excitations described by primary fields in CFT, as was done in reference (Alcaraz et. al., Phys. Rev. Lett. 106, 201601 (2011)), of which this work is a completion. An alternative derivation is presented, together with numerical verifications of our results in different models belonging to the c=1,1/2 universality classes. Oscillations of the Renyi entropy in excited states and descendant fields are also discussed.Comment: 23 pages, 13 figure