Chirality Effects on Peptide Self-Assembly Unraveled from Molecules to Materials

Self-assembling short peptides are attractive minimal systems for mimicking the constituents of living systems and building (bio)materials. The combination of both D- and L-amino acids into heterochiral sequences is a versatile strategy for building durable supramolecular architectures, especially when their homochiral analogs do not self-assemble. The reasons for this divergent behavior have remained obscure until now. Here, we elucidate how and why homochiral and heterochiral peptides behave differently. We identify a key spectroscopy signature and its corresponding molecular conformation, whereby an amphiphilic structure is uniquely enabled by the peptide stereochemistry. Importantly, we unravel the self-assembly process as a continuum from the conformation of single molecules to their organization into nano- and microstructures and through to macroscopic hydrogels, which are probed for cytotoxicity in fibroblast cell culture. In this way, (bio)material properties at the macro-scale can be linked to the chemical structure of their building blocks at the angstrom scale. Nature makes pervasive use of homochirality (e.g., D-sugars and L-peptides) to assemble biomolecules, whose interactions determine life processes. D-amino acids rarely occur, and their effects are not yet completely understood. For a long time, structural complexity (e.g., polypeptides and constrained molecules) was considered a requirement for achieving defined conformations that ultimately allow biomolecule recognition and function. Here, we detail how minimalist building blocks can adopt conformations with a characteristic spectroscopic signature, whereby substitution of just one L-amino acid for its D mirror image leads to a divergent path for assembly in water. Subtle molecular variations are amplified through increasing size scale all the way to macroscopic differences that are visible to the eye. Ultimately, the design of heterochiral (bio)molecules thus provides an alternative approach to shed new light on the supramolecular interactions that define life as we know it. This work explains why and how heterochiral and homochiral tripeptides differ in their assembly in water. A characteristic spectroscopic signature is assigned to molecular conformation. We monitor the process as a continuum from the molecular scale to the macroscopic biomaterials so that the final properties are linked to chemical structure of the building blocks. This work lays the foundation for the design of supramolecular hydrogel biomaterials based on short sequences of hydrophobic D- and L-amino acids

Shallow geophysics of the Asinara Island Marine Reserve Area (NW Sardinia, Italy)

We present a high-resolution swath bathymetric and backscatter map of the entire sector of the Marine Reserve Area (MRA) of the Asinara Island, along with a geological and sediment thickness map derived from the interpretation of a large set of high-resolution seismic profiles, and an airborne-derived hyperspectral image of the Asinara Island. Acquired data show that most of the eastern marine sector of the Asinara Island is characterized by quite gentle bathymetric gradients, whereas the western coastline appears to be very indented, with an articulated and rough morphology of the seafloor, which deepens sharply towards the open sea. The maps presented in this study at the 1:50.000 scale do not only provide the first, high-resolution bathymetry of the MRA of the Asinara Island but also may furnish the base for the creation of a benthic habitat map and a more comprehensive maritime spatial planning of this protected area

Open data, Science and Society: launching Oasis, the flagship initiative of the Istituto Italiano di Antropologia

The Open Data philosophy has gained considerable momentum in recent years, both in society and the scientific community. The accessibility via web of open data from the public sector has remarkably increased in the last decade, although there are substantial differences among nations (http://datacatalogs.org/). The expectation of many citizens, organizations and pressure groups (the so called “open government” movement) is that the free release of data from public administrations may help increase government transparency and accountability

Solar radiation effects on the Sardinia Radio Telescope performances

The Sardinia Radio Telescope, a 64-metre diameter fully steerable radio telescope operated by INAF, will be upgraded in order to extend its current operating frequency range 0.3-26.5 GHz up to 116 GHz, thanks to a National Operational Program (PON) funding assigned to INAF by the Italian Ministry of University and Research. The PON project is organized in nine Work Packages, one of which is dedicated to the accomplishment of a sophisticated metrology system designed to monitor the cause of the pointing errors and the reflector surface deformations. The entire antenna structure will therefore be equipped with a network of sensors, like thermal sensors, inclinometers, accelerometers, collimators, anemometers, strain gauges and others, to study environmental stresses and how they affect the SRT performances. This work is devoted to the investigation of the thermal stress effects produced by solar radiation. In particular, two analyses are carried out to confirm the relevance of a thorough temperature monitoring system, both conducted using Finite Element Analysis. First, a possible approach for the simulation of realistic thermal scenarios due to insolation is proposed and the effects on the pointing accuracy are analysed. Second, a feasible method to study the impacts that a differential heating of the Back Up Structure (BUS) produces on the radio telescope main reflector surface is presented. Finally, these effects are analysed as optical aberrations and modelled in terms of Zernike polynomials

The high-frequency upgrade of the Sardinia Radio Telescope

We present the status of the Sardinia Radio Telescope (SRT) and its forthcoming update planned in the next few years. The post-process scenario of the upgraded infrastructure will allow the national and international scientific community to use the SRT for the study of the Universe at high radio frequencies (up to 116 GHz), both in single dish and in interferometric mode. A telescope like SRT, operating at high frequencies, represents a unique resource for the scientific community. The telescope will be ideal for mapping quickly and with relatively high angular resolution extended radio emissions characterized by low surface brightness. It will also be essential for spectroscopic and polarimetric studies of both Galactic and extragalactic radio sources. With the use of the interferometric technique, SRT and the other Italian antennas (Medicina and Noto) will operate within the national and international radiotelescope network, allowing astronomers to obtain images of radio sources at very high angular resolution

Status of the High-Frequency Upgrade of the Sardinia Radio Telescope

The Sardinia Radio Telescope is going through a major upgrade aimed at observing the universe at up to 116 GHz. A budget of 18.700.000 E has been awarded to the Italian National Institute of Astrophysics to acquire new state-of-the-art receivers, back-end, and high-performance computing, to develop a sophisticated metrology system and to upgrade the infrastructure and laboratories. This contribution draws the status of the whole project at eight months from the end of the funding scheme planned for August 2022

Buone pratiche di riconversione e riuso degli aeroporti militari storici: un confronto internazionale

BEST PRACTICE OF RECONVERSION AND REUSE OF HISTORICAL MILITARY AIRPORTS: AN INTERNA TIONAL OVERVIEW The reconversion of historical airport infrastructures is part of the broader international issue on the reuse and enhancement of military assets, underused or dismantled as a consequence of the changes in the political and administrative strategies. A heterogeneous scenario emerges from the census of different adaptive reuses in Italy and abroad, representing different approaches adopted in the international context on these special purpose architectures. Against a still limited number of protected sites, many interesting examples of reconversions can be found in Italy; high degrees of protection and best practices arise from the Anglo Saxon and German experiences; innovative approaches come from the American projects. The research shows the relevance of an accurate knowledge of the heritage in the definition of new uses. Tangible and intangible values can guide towards sustainable solutions, respectful of the material authenticity and the historical identity of places. For this reason, the scientific research can drive future choices through preliminary 'exploratory projects' capable of investigating potenti al and limits of the various possible strategies. The protocols tested in the case of airport infrastructures also represent an important methodological contribution for the management of large real estate complexes

Stratigrafia e paesaggio: riflessioni per una tutela dinamica del patrimonio costiero di Cagliari | Landscape and stratigraphy: towards a dynamic protective management of Cagliari’s coastal heritage

The paper illustrates the first results of a wider research that the Faculty of Architecture of the University of Cagliari is carrying out with the collaboration of the local Superintendency of Cagliari, mainly focused on the protection of Sardinian defence landscapes, and particularly of coastal fortified towns. The case study is Cagliari, a highly stratified military stronghold and, specifically, its waterfront. The research starts with the reconstruction of the origin and evolution of the urban area, as a consequence of its military power and its strategic defensive role in the Mediterranean. The 'face' of the town towards the sea, that is the interesting waterfront of via Roma and the historic dockyards, has completely changed with the decommission of the military stronghold, turning the defence aspect into a cultural and touristic one. The analysis of this peculiar part of the city has highlighted how the stratigraphic approach, already widely experienced in individual areas (geological, archaeological, architectural and urban), can be a guiding principle of the “landscape restoration”. This term is used to outline the conservation of historical matter together with the management of transformations and functional integrations, with particular attention not only to the treatment of the single component unit, but also to the interface solution, understood as the spatial and temporal extent of interaction between history, environment, society. At the same time, the research also gives a contribution to the definition of a specific role of restoration in terms of landscape protection. The complexity of the outcomes belonged from the theoretical speculation concerning architectural restoration can constitute an important methodological heritage for the definition of new tools for the interpretation and the dynamic management of the landscape transformations

Italian Populations During the Copper Age: Assessment of Biological Affinities Through Morphological Dental Traits

The Copper Age (3rd millennium BC) was characterized by considerable socioeconomic transformations and coincided with the discovery of metallurgy. In this study we reconstruct the peopling of Italy during this period on the basis of dental morphology traits. Dental remains from 41 sites throughout Italy were analyzed; only three of the sites (Laterza and two from Sicily) span from the late Copper Age to the early Bronze Age. To work with adequate samples, we pooled the collections into nine geographically and culturally homogeneous groups. Dental morphological traits were scored on 8,891 teeth from 1,302 individuals using the ASUDAS scale. The correlation between the mean measure of divergence and geographic distances (calculated as air distances) was computed. Multidimensional scaling with the minimum spanning tree and maximum-likelihood methods was applied to assess the relationships between groups. The results revealed a substantial genetic homogeneity among the populations throughout the Italian peninsula during the Copper Age with the exception of Sardinia, which tends to diverge from the continental samples. Phenetic and geographic distances correlate highly significantly only when the southern samples from Sicily and Laterza are removed from the analysis, which indicates that these groups may have experienced genetic admixture with external populations