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Different works in literature have reported that nonlinear controllers based on the energy approach are not effective to completely swing-up an inverted pendulum subjected to friction. Most studies trying to solve this issue consider static friction models in the design of controllers. This consideration is mainly because the stability proof of the system with dynamic friction in closed-loop is difficult. Hence, this paper presents a nonlinear controller with friction compensation to swing-up a Furuta pendulum with dynamic friction. With this aim, we consider that only the active joint of the system is subjected to friction, which is represented via a dynamic model, namely, the Dahl model. We first present Furuta Pendulum dynamic model with dynamic friction. Then, by slightly modifying an energy-based controller that has been previously reported in literature and by including friction compensation, we propose a nonlinear controller that allows to swing-up completely a Furuta pendulum subjected to friction. The unmeasurable friction state is estimated through a nonlinear observer and a stability analysis of the closed-loop system is accomplished with the direct Lyapunov method. Finally, successful experimental results are presented for a Furuta pendulum prototype built by authors. This shows the effectiveness of the proposed controller in achieving a complete swing-up of the Furuta pendulum, in a time feasible for experimental implementation, and ensuring closed-loop stability. [Display omitted] The present paper proposes a nonlinear controller with dynamic friction compensation that experimentally achieves a complete swing-up for the Furuta pendulum in a short time, whose stability analysis is accomplished with the Lyapunov method • A nonlinear control to swing-up a Furuta pendulum with dynamic friction is proposed. • Control is an improved modification of an energy control previously reported. • Modification allows formally demonstrating swing-up accomplishment despite friction. • Three problems by friction in swinging-up inverted pendulums in practice are solved. • Improved performance of the control is successfully verified in practical application. [ABSTRACT FROM AUTHOR]

Since the beginning of humanity, man has generated various theories to explain the formation of the Universe, and the origin of life on Earth. However, even while these theories coincide sometimes, they are also subject to controversy, but it was Albert Einstein who postulated the theory of special and general relativity, in the understanding of the formation and functioning of the Universe. Meanwhile, for decades, experiments have been carried out regarding the origin of life in our planet. While these experiments have made relevant contributions in obtaining essential chemical blocks of life, obtaining a functional biomolecule as authoritative proof of how life began has not been found. This shows that not all variables implicated in the origin of life have been considered. For a better comprehension of the origin of life, the objective of this work was to synthesize calcium carbonate biomorphs in the presence of various biomolecules in atmospheric conditions that emulate the Precambrian era and also in the conditions of our current atmosphere. Our results show that both in the conditions that emulate the Precambrian era and in the current atmosphere, biomorphs show a spherical morphology, which is compatible with life forms. But a functional biomolecule that could indicate a beginning of life was not obtained. For the purpose of explaining the reason for which it has not been possible to obtain a pioneer organism, such as occurred in the primeval era, I have proposed a theory of life in which I have considered the interaction of the various lengths of wave of the electromagnetic spectrum, the magnetic fields of the various atoms, the energy and the physical laws that rule the Universe. The proposed equation for the origin of life (L = amc2) is grounded in the equation of special relativity (E = mc2) and general relativity for the Universe, equations that specify how the local density of matter and energy determine the geometry of space-time. For this aforementioned equation: L represents life, the letter "a" stands for absorption of a specific type of equivalent to the Higgs Boson, "m" corresponds to matter and finally "c" is the light speed. Considering the four factors of space-time-matter-energy that participated in the origin of life in the equation that I propose, the absorption that matter should have been also incorporated, which should be generated based on the Higgs Boson, also known as the particle of God, or perhaps, on another particle equivalent to that of the Higgs. The origin of life therefore fulfills the four factors of space-time-matter-energy in the aforementioned equation L = amc2. [Display omitted] [ABSTRACT FROM AUTHOR]

The origin of life has been marked by existing chemical, physical and atmospheric conditions in the primeval era of Earth. In this sense, experiments have been carried out that emulate the conditions of the Precambrian era, where organic blocks such as amino acids, sugars, organic compounds and O 2 have been synthesized from the elements of this condition. Nevertheless, even while these results have been disruptive, allowing a significant advance in the origin of life, no functional biomolecules have been synthesized. Considering the work done previously, as a starting point and the evidences of the synthesis of biomorphs in the presence of biomolecules, the objective of this study was the synthesis of barium silico-carbonate biomorphs, based on biomolecules in Precambrian conditions. The purpose of this is to identify if it is possible to obtain functional biomolecules. The results showed that the barium biomorphs synthesized in conditions that emulate the primitive era present spherical or circular morphology, with a chemical composition that corresponds to the polymorphs of witherite, goethite and carbonaceous material (CM) such as protein, carbohydrate and phosphate group bonds. However, the synthesis of an active or functional biomolecule was not possible. The results therefore show that to be able to obtain a functional biomolecule that could be considered a sign of life springing from organic and inorganic compounds, it is necessary to involve other factors heretofore not considered. This is due to the fact that chemical elements per se , together with some atmospheric factors that have been described which apparently permitted the formation of the protocell in the primitive era of Earth, are not sufficient to obtain functional biomolecules. In this way, the origin of life may be understood from the equation of life (L = amc2), considering all involved factors and not only the chemical composition of elements that make up various organisms in combination with only some atmospheric factors. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Micologia is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Iberoamericana de Micologia is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The synthesis of crystals through biomineralization is a process of protection and support preserved in animals, protists, moneras, plants and fungi. The genome of every species has evolved to preserve and/or modify the formation of one or another type of crystal, which may be of the organic or inorganic type. The most common inorganic crystals identified in organisms include calcium carbonate (CaCO 3 ), calcium phosphate (CaP), calcium oxalate (CaOx), magnetite or greigite, and sulfides of cadmium (CdS), mercury (HgS) and lead (PbS). Organic crystals are of the protein or ice type. The formation of both types of crystals requires biomolecules such as proteins. This paper reviews the proteins involved in the synthesis of different crystals in distinct biological systems, in order to understand how each organism has adapted its genome to preserve essential mechanisms such as biomineralization, which has enabled them to survive in a changing environment for millions of years. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Micologia is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As known currently, in the formation of the Earth, minerals have played a pivotal role going from the formation of the hydrosphere, the lithosphere, and all Earth components until the origin, evolution, and maintenance of life. The first signs of magnetism are found in komatiites. In the origin of life, minerals were responsible for concentrating, aligning, and acting as templates and catalyzers, allowing for the formation of bonds among the first biomolecules to form polymers, which eventually became assembled to give rise to the pioneer organism in the Precambrian. Besides, minerals allowed the DNA to be the information storing molecule, even though it was not the first biomolecule. Another function of minerals was to protect the organic complexes against ultraviolet radiation and hydrolysis, a fundamental action to preserve life in the Precambrian where high UV radiation prevailed. Minerals not only favored the origin of life but also became part of the organisms that inhabit the Earth, including species of the five kingdoms, comprising from microorganisms to higher organisms. How minerals participated in the origin of life still has unresolved questions, for which to understand the minerals' participation since the formation of the Earth until becoming part of the structure of organisms from the five kingdoms, we reviewed the following topics, which will contribute to the understanding of the implication of minerals in the origin of our planet and life on it: i) the synthesis of the chemical elements from which the first mineral were obtained in the Earth, ii) the factor that favored the formation of minerals in the Earth, iii) the implication of minerals as the basis for the synthesis of the first biomolecule and, eventually, the pioneer organism, as well as the biomineralization mechanism that has been proposed to account for the mineral part contained in the structure of the organisms from the different kingdoms, and iv) the models that allow emulating the mechanisms by which minerals participated in the synthesis of the first biomolecule; in this way, for example, the Precambrian microfossils are so simple morphologically (spheres, subspheres, and hemispheres) that they can easily be imitated by hollow mineral growths, known as biomorphs. Although these can interfere with the study of actual microfossils, they remain as key points for the study of the origin of life. [Display omitted] [ABSTRACT FROM AUTHOR]

This contribution is a scientific journey divided into three parts. In the first part, we review the role that silica biomorphs of alkaline earth metals have played in the formation of complex structures as a reminiscence of the chemistry of the primitive life on Earth. These biomorphs, and their variety of forms synthesized by simple chemical reactions, can nowadays be experimentally used to explain some mechanisms of biomineralization in living organisms. In the second part, we review the role of calcium carbonates in the formation of eggshells in avian. The mechanism of the mineral eggshell´s formation of the biogenic calcite deposited on an organic matrix is revised. The competitive crystal growth mechanism of the mineralized part orientates these crystals preserving the semispherical shape of the egg. We are using these eggshell formations as a second model to understand the biomineralization processes in Nature. The third and final part is about the importance that biomineralization concepts have to produce hybrid materials for the future. This has allowed us to obtain tailored size control of complex morphologies by synthetic chemical procedures that give rise to these new materials' specific forms and ad hoc properties. We conclude this part with the advantage of knowing the biological mechanisms, based on molecular biology concepts, to obtain protein crystals in vivo and in cellulo techniques. Both methods use the cellular machinery of growing biocrystals in specialized cells that have evolved through millions of years. This new way of producing protein crystals has been trending topic for modern crystallography when using the facilities of the X-ray free-electron lasers (four generation of synchrotrons) for megahertz serial crystallography. [ABSTRACT FROM AUTHOR]

Under alkaline conditions, silica forms self-assembled mineral compounds which are similar in morphology, nanostructure, and texture to the hybrid biomineral structures that, millions of years ago gave to life. In this review we propose that, during the earliest history of this planet, there was a geochemical scenario that led to large-scale production of both simple and complex organic compounds, many of which were important for prebiotic chemistry. The production was based on a high concentration of silica and high pH. Two main factors affected this process: a) a source of simple carbon molecules that were either synthesized abiotically from reactions associated with serpentinization, or carried by meteorites and produced by their impact on Earth, and b) the formation of self-organized silica-metal mineral compounds that catalyzed the condensation of single molecules in a reduced methane-rich atmosphere. We discuss the plausibility of this geochemical scenario and its catalytic properties and the transition towards a slightly alkaline to Neutral Ocean. [ABSTRACT FROM AUTHOR]

Abstract: The cell wall of members of the Sporothrix schenckii complex contains highly antigenic molecules which are potentially useful for the diagnosis and treatment of sporotrichosis. In this study, 2 immunoreactive antigens of 60 (Gp60) and 70 kDa (Gp70) were detected in the cell wall of the yeast morphotypes of Sporothrix brasiliensis and Sporothrix globosa. [Copyright &y& Elsevier]

Studies dealing with the response of microorganisms to oxidative stress require the dissolution of oxidant agents in an appropriate solvent. A commonly used medium is dimethyl sulfoxide, which has been considered as an innocuous polar solvent. However, we have observed significant differences between control, untreated cells and those receiving increasing amounts of the oxidant and hence increasing amounts of DMSO, to the maximum allowed of 1%. Here we show that, while this solvent does not influence yeast cell viability, it does affect expression of cell wall proteins as well as catalase activity. Therefore, its use in future studies of oxidative stress as an innocuous solvent should be reconsidered. [ABSTRACT FROM AUTHOR]