Nearly-freestanding supramolecular assembly with tunable structural properties

The synthesis and design of two-dimensional supramolecular assemblies with specific functionalities is one of the principal goals of the emerging field of molecule-based electronics, which is relevant for many technological applications. Although a large number of molecular assemblies have been already investigated, engineering uniform and highly ordered two-dimensional molecular assemblies is still a challenge. Here we report on a novel approach to prepare wide highly crystalline molecular assemblies with tunable structural properties. We make use of the high-reactivity of the carboxylic acid functional moiety and of the predictable structural features of non-polar alkane chains to synthesize 2D supramolecular assemblies of 4-(decyloxy)benzoic acid (4DBA;C[Formula: see text] H[Formula: see text] O[Formula: see text] ) on a Au(111) surface. By means of scanning tunneling microscopy, density functional theory calculations and photoemission spectroscopy, we demonstrate that these molecules form a self-limited highly ordered and defect-free two-dimensional single-layer film of micrometer-size, which exhibits a nearly-freestanding character. We prove that by changing the length of the alkoxy chain it is possible to modify in a controlled way the molecular density of the “floating” overlayer without affecting the molecular assembly. This system is especially suitable for engineering molecular assemblies because it represents one of the few 2D molecular arrays with specific functionality where the structural properties can be tuned in a controlled way, while preserving the molecular pattern

The impact of digital technologies on the bond between parents and adolescent children

El presente proyecto se propone indagar sobre el impacto que las nuevas tecnologías de información y comunicación (TIC) y los entornos digitales tienen sobre el vínculo entre padres e hijos adolescentes, en familias de La Plata y Gran La Plata. En el marco de las transformaciones familiares, sociales y culturales de estas últimas décadas, los significados que demarcan los territorios generacionales construyen también novedades en una espacialidad diferente, los territorios digitales, donde la tecnología se ve entretejida de modo ineludible con las tramas constructivas de la subjetividad. Las nuevas formas de familia y las formas actuales de subjetividad adolescente despliegan modos novedosos de vinculación intra e intergeneracionales. Nos proponemos investigar las formas que encuentran los padres y los hijos adolescentes para vincularse entre sí, en un mundo en plena transformación. El corrimiento y la reubicación generacional de los hijos al abandonar la infancia, desafían a un trabajo de simbolizar la diferencia generacional en una operatoria de asesinato simbólico de las figuras parentales y asunción de los emblemas identificatorios de un linaje. Brecha generacional que hoy plantea una brecha alfabeto-generacional, entre nativos e inmigrantes digitales, que pone en jaque los sentidos de continuidad / discontinuidad, transmisión y pertenencia.This project aims to investigate the impact that new information and communication technologies (ICT) and digital environments have on the bond between parents and adolescent children, in families of La Plata and Gran La Plata. In the framework of the family, social and cultural transformations of these last decades, the meanings that demarcate the generational territories also construct novelties in a different spatiality, the digital territories, where technology is inextricably interwoven with the constructive plots of the subjectivity. We intend to investigate the ways that parents and teenage children find in these new plots to link with each other, in a world in full transformation. The shift and generational relocation of the children to abandon childhood and register the novelty of the possibility of reproduction, challenges a work to symbolize the generational difference in an operation of symbolic murder of the parental figures and assumption of the identifying emblems of a lineage. Generational gap that today poses an alphabet-generational gap between natives and digital immigrants puts in check the senses of continuity / discontinuity, transmission and belonging.Facultad de Psicologí

Virtualization of everyday life in isolation time: impact of digital technologies on parents and adolescent children

Desde el Proyecto EL IMPACTO DE LAS TECNOLOGÍAS DIGITALES EN EL VÍNCULO ENTRE PADRES E HIJOS ADOLESCENTES, DE LA PLATA Y GRAN LA PLATA, presentamos una línea de investigación reciente y su reformulación de preguntas e hipótesis, con resultados preliminares, resituados en contexto de pandemia. Con el propósito de poner en diálogo, problematizar y compartir el desarrollo de nuestro quehacer como investigadores en una coyuntura tan compleja como novedosa que estamos atravesando, abrimos nuevos interrogantes a la vez que diseñamos estrategias en situación. Compartimos las reformulaciones de instrumento y muestra en un marco de flexibilidad metodológica. Y nos referimos al efecto y modo de virtualización de lo cotidiano en familias con hijos adolescentes en relación a tres ejes: usos y novedades de la tecnología digital en pandemia, en adolescentes y adultos; establecimiento de acuerdos y ordenamientos intergeneracionales; efectos y simbolizaciones posibles de lo que se presenta: espacio-tiempo y cuerpo.This paper aims to present a recent line of research and its reformulation of questions and hypotheses, on the impact that new information and communication technologies (ICT) and digital environments have on the relationship between parents and adolescent children, in families of La Plata and Gran La Plata. (2020-2022), traversed by the context of the COVID-19 pandemic. The use of technology, within the framework of the sanitary measures of isolation and social distancing, slowly acquired a character of imposition in the way of bonding with the other, questioning its use by choice. Faced with the current health crisis and its effects on daily life, it was necessary to make place for new explorations from a first survey. Initial reformulation of aspects and times of the methodological strategy resulting in the flexibility of the qualitative design.Facultad de Psicologí

Synthesis of Ni-Doped Tremolite Fibers to Help Clarify the Aetiology of the Cytotoxic Outcome of Asbestos

Asbestos fibers act as complex crystal-chemical reservoirs susceptible of releasing potentially toxic elements (such as ions impurities) into the lung cellular environment during permanency and dissolution. To comprehend the exact pathological mechanisms that are triggered upon inhalation of asbestos fibers, in vitro studies on possible interactions between the mineral and the biological system have been carried out mostly by using natural asbestos. However, this latter comprises intrinsic impurities such as Fe2+/Fe3+ and Ni2+ ions, and other eventual traces of metallic pathogens. Furthermore, often, natural asbestos is characterized by the co-presence of several mineral phases, fiber dimensions of which are randomly distributed in width and in length. For these reasons, it is albeit challenging to precisely identify toxicity factors and to define the accurate role of each factor in the overall pathogenesis of asbestos. In this regard, the availability of synthetic asbestos fibers with accurate chemical composition and specific dimensions for in vitro screening tests would represent the perfect tool to correlate asbestos toxicity to its chemico-physical features. Herein, to palliate such drawbacks of natural asbestos, well-defined Ni-doped tremolite fibers were chemically synthesized in order to offer biologists adequate samples for testing the specific role of Ni2+ in asbestos toxicity. The experimental conditions (temperature, pressure, reaction time and water amount) were optimized to produce batches of asbestos fibers of the tremolite phase, with uniformly distributed shape and dimensions and a controlled content of Ni2+ metal ions

Hazardous Elements in Asbestos Tremolite from the Basilicata Region, Southern Italy: A First Step

In this paper, we report the quantification of potentially toxic elements (PTEs) hosted into two tremolite asbestos from Episcopia and San Severino Lucano villages (Basilicata region, Southern Italy). Micro X-ray fluorescence and Inductively Coupled Plasma spectroscopy with Optical Emission Spectrometry techniques were used to quantify the concentration of major, minor (Si, Mg, Ca, Al, Fe, Mn) and trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Sb, Sn Sr, Ti, Te, V, W, Zn, Zr), with the aim of providing available data useful for the determination of the asbestos fibers toxicity. Results show that in the two studied samples there exist high concentrations of Fe, Mn, Cr and Ni which could lead to the high toxicity of the mineral fibers. By considering the pseudo-total PTEs amounts in each tremolite asbestos, it is possible to affirm that one of the samples is more enriched in toxic elements than the other one (3572 ppm versus 1384 ppm). These PTEs can represent a source of risk to human health since they may be transported away from the geological outcrops, through asbestos in the air, water and soils and thus encountering the human body

Rejuvenating Agents vs. Fluxing Agents: Their Respective Mechanisms of Action on Bitumen Subjected to Multiple Aging Cycles

During the service life of road pavements, the asphalt, more specifically the surface layer, is susceptible to aging due to the oxidation phenomenon and the loss of the volatile compounds of bitumen, which functions as the binder in the asphalt conglomerate. Road pavements that undergo a significant level of oxidation become rigid and susceptible to cracking, and new paving operations will need to be carried out in order to make the road ideal for continued use. However, due to recent eco-friendly initiatives that have been put in place to promote a circular economy and also mitigate the problem of environmental pollution, the asphalt industry is currently devising means of safeguarding the environment while also minimizing the cost of the production of road pavements without compromising their quality. As a general solution to this issue, old asphalt pavements are removed and recycled as reclaimed asphalt (RA), with the aim of restoring the original properties of the binder in such a way that RA can be re-used in combination with virgin materials to produce new road pavements. In this research study, virgin bitumen is subjected to a cycle of aging, after which two recycling agents are used to modify the aged bitumen samples. These samples containing the different recycling agents were subjected to a second aging cycle, a second recycling agent treatment, and then again subjected to a final aging cycle. The two recycling agents have different compositions, and each one of them could be either a rejuvenating agent or a fluxing agent. This study investigates the effect of these recycling agents on aged bitumen, and how the addition of these recycling agents influences the changes observed between virgin, aged and recycled bitumen. This would enable an understanding of rejuvenation and fluxing mechanisms, which will help in the classification of the asphalt recycling agents as either rejuvenating or fluxing agents. Dynamic shear rheology, atomic force microscopy, and light microscopy to determine asphaltene melting point were the techniques used in this investigation. The results obtained demonstrate that rejuvenating agents are more effective in reversing the effects of oxidative aging on the bitumen binder than fluxing agents

Assessment of Naturally Occurring Asbestos in the Area of Episcopia (Lucania, Southern Italy)

Over the last few years, the risk to human health related to asbestos fiber exposure has been widely demonstrated by many studies. Serpentinites are the main rocks associated with naturally occurring asbestos (NOA). In order to investigate the presence of NOA, a mineralogical study was conducted on eleven serpentinite samples collected nearby the village of Episcopia (Lucania, Southern Italy). Various analytical techniques such as X-ray powder diffraction (XRPD), scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS) and derivative thermogravimetry (DTG) were used to determine the occurrence of asbestos minerals and to make morphological observations. Results pointed out that all of the samples contain asbestos minerals (e.g., tremolite, actinolite and chrysotile). Moreover, it was observed that both natural processes and human activity may disturb NOA-bearing outcrops and provoke the formation of potentially inhalable airborne dust causing the release of asbestos fibers into the environment, thereby increasing the risk to human health. For this reason, our study aims to highlight the requirement of a natural asbestos survey and periodic update in the area

Effects of methyl groups in a pyrimidine-based flexible ligand on the formation of silver(I) coordination networks

A novel flexible ligand with methyl substituted pyrimidine rings and thioether spacers has been synthesised and the corresponding 1 : 1 silver(I) adducts have been obtained by interaction with different silver(I) salts AgX (where X = NO3 , BF4 , ClO4 , CH3SO3 , CF3CO2 , and CF3CF2CF2CO2 ). The X-ray single crystal structure determination of two of the new silver(I) adducts (X = NO3 and CF3CO2 ) has proved the formation of coordination polymers with Ag(I) ions almost linearly coordinated to two nitrogen atoms of the pyrimidine rings of the multitopic ligand used. The linear coordination mode shown by the new flexible ligand is induced by the presence of the substituents on the pyrimidine rings, regardless of the type of the AgX salt used in the formation of the respective silver(I) derivatives. This observation represents a neat change in comparison to the already reported series of complexes with unsubstituted (and otherwise identical) ligands, in which dinuclear coordination units have been invariably obtained. Computational investigations have been performed with the aim of explaining such an observed change. A computational comparison of a known dinuclear complex and its related polymeric one has been detailed here and has allowed us to highlight the importance of the introduced substituents in changing the ligand interactions internally to their coordination units and among adjacent units in the solid phases

Bioactive Ag(i) coordination complexes as dopants for castor oil plasticized ethylcellulose films†

<jats:p>New ethylcellulose films doped with bioactive Ag(<jats:sc>i</jats:sc>) complexes and a natural plasticizer are prepared and characterized. Their antibacterial activity makes them potential active food packaging materials.</jats:p&gt