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Τρίτη 20 Αυγούστου 2019

Man is the measure of all things

Abstract

Our system of measures referred to human proportions and human perception, as Protagoras stated, is “Man is the measure of all things”. In this paper, we present an overview of the measure of Man as a travel on time from the point of view of the past historical development to the future with the insight of different disciplines such as Anthropology, Ergonomics, and Human Factors. The key concept is that all the most famous scholars, architects artists and philosophers that have been working on system of human measures such as Polyclitus, Vitruvius and Leonardo until Le Corbusier are designers of Human canonical proportion and they design the things with the measure of their “Canonical Human”. We are looking to create a design with the differentiation of the measure of the “Real Humans”. The real human is not a canon but can be measured applying methodological international standards to obtain an anthropological database and to represent human variability on the base of standardized statistics for ergonomic design. This essay presents the result of 50 years of study at the Laboratory of Anthropometry and Ergonomics in the Turin University (Italy), applying Anthropometry of the real human evolution and Earth adaptation as result of the main factors: “gravity”, also investigated on context without this factor that is in “Outer Space”. In the Laboratory, researches were conduced not only to study past and present human populations, but also to deduce potential future expectations.

Solar-driven chemistry: towards new catalytic solutions for a sustainable world

Abstract

The topic of production of useful chemical compounds with the help of solar light has been debated at a recent meeting organized in Rome on October 18 and 19, 2018, by the Accademia Nazionale dei Lincei. Some of the contributions presented at this event are collected in this special issue of the Rendiconti Lincei. Scienze fisiche e Naturali. In this paper, we briefly discuss some recent results concerning the use of solar energy by artificial photochemical reactions for four important applications: (i) conversion of solar energy into fuels or (ii) conversion of sunlight into electrical energy, (iii) use of solar energy to perform organic synthesis that cannot be obtained by conventional chemistry, and (iv) photochemical reactions to reduce pollution.

Dye-sensitized photocatalytic and photoelectrochemical hydrogen production through water splitting

Abstract

This review points out some of our recent advancements in dye-sensitized photocatalytic and photoelectrochemical hydrogen production. The dye sensitization of a semiconductor (SC) surface plays a central role. The dye has the task to improve the light harvesting of the system and guarantees a fast charge transfer to the SC, while avoiding charge recombination reactions that might reduce its efficiency. The introduction of different features and exploitation of molecular designs led to the development of twelve new dyes with a “push–pull” di-branched structure. The design of the molecular structure and geometry improves light harvesting, stability under long-term irradiation, and surface properties. The dyes have been investigated in a photocatalytic device, and then the most representative molecules have been studied also in photoelectrochemical cells (PEC), in the presence either of a sacrificial electron donor (SED), or of a water oxidation catalyst (WOC). The planar structure of the carbazole-based dye enhanced the photocatalytic hydrogen production activity almost tenfold compared to the phenothiazine derivative characterized by a butterfly-like structure; the latter was endowed with a better performance in the photoelectrochemical hydrogen production.

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Bioaccumulation of potentially toxic elements in tree and vegetable species with associated health and ecological risks: a case study from a thermal power plant, Chandrapura, India

Abstract

The working of thermal power plant (TPP) in an area is the primary source of pollution, because it releases potentially toxic elements (PTEs) laden fly ash (FA), which may lead to serious health and ecological risks. This study assessed the current status of pollution in the nearby areas of TPP by measuring the concentration of PTEs (As, Cd, Cr, Hg, and Pb) in FA, soils (roadside, forest, agricultural, and residential areas), tree leaves (Albizia lebbeck and Madhuca longifolia), and vegetables (Raphanus sativus and Allium cepa). Hg concentration in FA was found to be lower (0.449 mg/kg) than global average Hg content (0.62 mg/kg). PTEs content in topsoil (0–15 cm) of the roadside area was comparatively higher (As, 4.56; Cd, 12.68; Cr, 72.53; Hg, 2.77; Pb, 46.05 mg/kg) than other areas. Bioaccumulation coefficient and transfer factor of As in M. longifolia and A. cepa were 1.03 and 0.30, respectively, which showed high accumulation of PTE. The ecological risk index (1561) was found to be very high in the roadside area, due to high values ecological risk factor of Cd (1268) and Hg (277) in the area. The total hazard quotients (THQs) posed by As, Cd, Cr, and Pb in vegetables were exceeding the safe limits (THQ > 1), suggesting that long-term consumptions of these vegetables may pose serious health risks. Therefore, the remediation measures are needed to minimize the pollution level in soil to reduce the health risk due to the exposure of PTEs.

Stagnation graphs and separatrices of local bifurcations in velocity and current density planar vector fields

Abstract

An elementary introduction to the notion of separatrix as a topologically closed surface bounding disjointed domains of a dynamic system is given within the theory of local bifurcations. Accordingly, local bifurcations of a two-dimensional dynamic system, occurring as a consequence of a small smooth change made to the value of a parameter, and causing a sudden qualitative change in its behavior, have been analyzed by visualizing velocity vector fields, related stagnation graphs, which collect stagnation lines, i.e., sets of equilibrium points corresponding to vanishing flow, and separatrices. According to a theorem by Gomes, the Poincaré index is conserved in the saddle-center and saddle-node bifurcations, which constitutes an important piece of information. The results obtained have mainly a didactic value and are preparatory to more advanced investigations of harder problems, encountered in the analysis of the quantum mechanical current densities \( {\varvec{J}}^\mathbf{B} \) and \( {\varvec{J}}^{{ \mathbf m}_{I}} \)induced in the electrons of a molecule by an applied magnetic field \( {\varvec{B}}\) and by the magnetic dipole \( {\bf{m}}_{I} \) at a nucleus I, and in the rationalization of magnetic response properties such as magnetizabilities, nuclear magnetic shielding, and nuclear spin–spin coupling. Applications to the study of bifurcation phenomena in chemical reactions are also possible.

Novel lanthanum-modified activated carbon derived from pine cone biomass as ecofriendly bio-sorbent for removal of phosphate and nitrate in wastewater

Abstract

A low-cost and high-efficiency adsorbent was developed by chemical activation of pine cone biomass with lanthanum chloride (La-PC) and applied for the simultaneous removal of phosphate (P) and nitrate (N) in aqueous solution. Equilibrium and kinetic experiments were performed to investigate the effects of operating conditions such as solution pH, coexisting ions, and initial concentration on the removal of P and N. The maximum adsorption capacities using La-PC were 68.2 and 46.6 mg g−1 for P; 25.8 and 21.4 mg g−1 for N, in single- and mixed system, respectively. Adsorption isotherm and adsorption kinetic studies showed that the Langmuir isotherm and second-order model were well fitted, indicating that the adsorption of P and N was dominated by a homogeneous and chemisorption. The presence of other anions such as SO42−, HCO 3 −, and Cl was slightly effected for removal of P and N. In addition, the regeneration of the adsorbent could be easily achieved and desorption efficiencies after three cycles were 89.4 and 76.5% for P and N, respectively. Based on the results, La-PC would be utilized as a promising material for removal of nutrients from water from aqueous solution.

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Silver halide-based composite photocatalysts: an updated account

Abstract

Silver halides are attractive materials for visible light-driven photocatalytic applications. To improve their stability under visible light irradiation, several strategies have been explored, among them the use of an inorganic support, thus promoting a synergistic effect between the two components which is beneficial for their photocatalytic performance. The present study aims to present and discuss advances on silver halide-based composite photocatalysts, thus providing an overview of the effect of different supports on the photocatalytic properties of the corresponding composites. Attention is devoted to silver halide composites based on three main classes of inorganic compounds that are (i) carbon-based materials, among them graphene oxide, reduced graphene oxide, graphene-like boron nitride, activated carbon, carbon nanotubes, graphitic carbon nitride; (ii) clay materials, among them cationic (silicates) and anionic (layered double hydroxides) clays; and (iii) layered zirconium phosphate.

A novel intracellular synthesis of silver nanoparticles using Desmodesmus sp. (Scenedesmaceae): different methods of pigment change

Abstract

The present study describes the role of cellular pigments in the biosynthesis of silver nanoparticles. The use of algae for nanoparticle synthesis has advantages such as being fast, eco-friendly, biocompatible, and non-toxic chemicals. However, it takes place in a shorter time and with lower cost than other biosynthesis methods. In this study, we synthesized silver nanoparticle intracellularly from 5 mM AgNO3 solution-mediated Desmodesmus sp. as reducing agent. The successful synthesis of silver nanoparticles was confirmed by UV–Vis, TEM, XRD and confocal analysis. It was observed that the algal cells synthesized under TEM analysis are intact and the nanoparticles accumulate in the compact inner region of the cells without forming aggregates. In the UV–Vis spectroscopy analysis, nanoparticle synthesis was performed in the first 24 h, which was confirmed by the reduction of chlorophyll content. In addition, this situation was seen in confocal microscopy analysis due to the autofluorescence of the Desmodesmus sp.

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Molecular beam studies of elementary reactions relevant in plasma/combustion chemistry: O( 3 P) + unsaturated hydrocarbons

Abstract

The identification of the primary products and the determination of their branching ratios as a function of translational energy (temperature) for multi-channel elementary (bimolecular) reactions of importance in combustion flames and plasma-assisted combustion still represent a challenge for traditional kinetics experiments. On the other hand, this kind of information is central for the detailed modeling of combustion/plasma systems. In this short review, the significant contribution provided in this area by the crossed molecular beam (CMB) scattering method with “universal” mass-spectrometric detection and time-of-flight analysis is illustrated. In particular, we describe the basics of the CMB technique empowered with “soft” electron-impact ionization as recently implemented in our laboratory, and report on its application to the study of the multi-channel elementary reactions of ground state atomic oxygen, O(3P), with unsaturated hydrocarbons containing two carbon atoms (acetylene and ethylene), three carbon atoms (propyne, propene, and allene), and also four carbon atoms (1-butene, 1,2-butadiene, and 1,3-butadiene), which are of paramount interest in combustion flames and plasma-assisted combustion of hydrocarbons. These studies are usually complemented in a synergistic manner by high-level electronic structure calculations of the underlying potential energy surfaces and related statistical (and dynamical when feasible) calculations of product branching ratios. The complementarity to kinetics studies and the implications of the dynamics results for the modeling of combustion/plasma chemistry will be commented on.

Morphogenetic stability of variegated Vanilla planifolia Jacks. plants micropropagated in a temporary immersion system (TIB ® )

Abstract

Key message

ISSR markers are useful to identify molecular changes in variegated vanilla (Vanilla planifolia Jacks.) plants derived from a temporary immersion system.

Abstract

Clonal propagation through in vitro cultures produces individuals that are identical to the parent plant from which they were subcultured. However, there is evidence of phenotypic variations between propagated clones. The most common phenotypic variations are changes in leaf pigmentation, i.e., variegated individuals. Many such phenotypic variations are exploited by the ornamental industry. In a previous study by our group on indirect organogenesis in vanilla (Ramírez-Mosqueda and Iglesias-Andreu in In Vitro Cell Dev Biol Plant 52:154–160, 2015), variegated Vanilla planifolia Jacks. plants were generated in vitro. A temporary immersion system allows for the mass propagation of plant material in liquid culture. The present study aimed to identify morphological and molecular changes that occurred in variegated plants obtained during micropropagation in a temporary immersion system, the TIB®. To achieve this, the morphology of plants micropropagated in TIB® was assessed and analyzed at the molecular level using inter-simple sequence repeats. Molecular variation was analyzed over four subcultures, each lasting 45 days. Plants showed 100% uniformity (monomorphism) and morphological stability, which were confirmed by the heritability of leaf pigmentation (variegated individuals) in all micropropagated plants over all four subcultures. This study demonstrates that high genetic and morphological stability was achieved in variegated V. planifolia genotypes that were micropropagated in TIB®. This would allow for the establishment of a clonal line of variegated plants with ornamental applications. In addition, 100% survival of the plants was observed during acclimatization. The study forms part of a wider long-term effort to assess the potential of mass propagation of variegated vanilla for ornamental purposes.

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