Fluorescent amino acids as versatile building blocks for chemical biology

Fluorophores have transformed the way we study biological systems, enabling non-invasive studies in cells and intact organisms, which increase our understanding of complex processes at the molecular level. Fluorescent amino acids have become an essential chemical tool because they can be used to construct fluorescent macromolecules, such as peptides and proteins, without disrupting their native biomolecular properties. Fluorescent and fluorogenic amino acids with unique photophysical properties have been designed for tracking protein–protein interactions in situ or imaging nanoscopic events in real time with high spatial resolution. In this Review, we discuss advances in the design and synthesis of fluorescent amino acids and how they have contributed to the field of chemical biology in the past 10 years. Important areas of research that we review include novel methodologies to synthesize building blocks with tunable spectral properties, their integration into peptide and protein scaffolds using site-specific genetic encoding and bioorthogonal approaches, and their application to design novel artificial proteins, as well as to investigate biological processes in cells by means of optical imaging. [Figure not available: see fulltext.]

SERUM DEPRIVATION-DEPENDENT MODULATION OF SPHINGOMYELIN SPECIES IN HN9.10 EMBRYONIC HIPPOCAMPAL CELLS.

Understanding the mechanism of apoptosis is necessary to improve the use of stem cells for the treatment of neurodegenerative disorders. In HN9 embryonic hippocampal cells, serum deprivation induces apoptosis preceded by sphingomyelinase (SMase) activation and raise of ceramide levels. It is not known so far whether the SMase degrades all the species of sphingomyelins (SMs) in the same way and if it is the only enzyme that uses SM to produce ceramide. In order to begin to address this aspect still unclear about the relationship between SM and HN9.10 apoptosis, we carried out the analysis of the main species of SM and phosphatidylcholine (PC) with the idea that SM could be partly used as a source of phosphorylcholine to synthesize PC. To better investigate this possibility we measured the enzymatic activity of the reverse-SM synthase. In addition, since the ceramides involved in starvation-induced cell death are unknown, we have studied the content of ceramide and sphingosine-1-phosphate species as metabolites of SM produced by both SMase and reverse-SMsynthase. Cells have been incubated with 10% (control) or 0.2% fetal calf serum for 48 h (deprived). Lipid species has been separated and measured by ultraperformance liquid chromatography tandem mass spectrometry. Reverse-SMsynthase activity was assayed by using 14C labelled SM. The results show that serum deprivation reduces total SM and in particular 18:1/16:0 SM whereas it increases total PC and in particular 18:1/18:0 PC. There is a 2-fold increase of ceramides 18:1/ 16:0 and 18:1/ 24:0 and of sphingosine-1-phoshate 18:1. Following serum deprivation, the activity of Reverse-SM synthase remains constant for 8 h, increases afterwards up to 3.82 –fold compared to control at 48h. In conclusion, SMase activation might lead to decrease of SM 18:1/16:0, increase in ceramide 18:1/16:0 which can originate sphingosine-1-phoshate 18:1. In addition SM could be a source for PC synthesis with fatty acid rearrangement. Individual ceramide species regulated by specific pathways in distinct subcellular compartments might execute distinct cellular function

Dynamic simulation of vega SRM bench firing by using propellant complex characterization

During the VEGA launcher development, from the 2004 up to now, 8 firing tests have been performed at Salto di Quirra (Sardinia, Italy) and Kourou (Guyana, Fr) with the objective to characterize and qualify of the Zefiros and P80 Solid Rocket Motors (SRM). In fact the VEGA launcher configuration foreseen 3 solid stages based on P80, Z23 and Z9 Solid Rocket Motors respectively. One of the primary objectives of the firing test is to correctly characterize the dynamic response of the SRM in order to apply such a characterization to the predictions and simulations of the VEGA launch dynamic environment. Considering that the solid propellant is around 90% of the SRM mass, it is very important to dynamically characterize it, and to increase the confidence in the simulation of the dynamic levels transmitted to the LV upper part from the SRMs. The activity is articulated in three parts: • consolidation of an experimental method for the dynamic characterization of the complex dynamic elasticity modulus of elasticity of visco-elastic materials applicable to the SRM propellant operative conditions • introduction of the complex dynamic elasticity modulus in a numerical FEM benchmark based on MSC NASTRAN solver • analysis of the effect of the introduction of the complex dynamic elasticity modulus in the Zefiros FEM focusing on experimental firing test data reproduction with numerical approach

Towards a digital twin-based intelligent decision support for road maintenance

The digitalisation, automation and robotisation of road inspection and maintenance technologies make it possible to collect bigger volumes of data and additional types of information about road infrastructure. Methodologies and tools to support road asset management decision-making are needed to exploit this new information, progressing towards predictive maintenance and improving different aspects of road asset management. This study presents a Digital Twin-based Decision Support Tool to assist road operators in road inspection, maintenance and upgrade. The goal of the paper is twofold. First, the architecture of the Digital Twin-based Decision Support Tool is presented, describing the main components and functionalities. The system is based on a Digital Twin (DT) that mirrors real road assets to integrate different sources of data and support the processing of low-level data into high-level information. The decision support tool (DST) is able to analyse the collected information and compute the road pavement condition to derive optimal intervention plans, addressing road section conditions, human and technical resources and other external constraints. Second, the application of the proposed architecture to road pavement maintenance is described, considering the Italian highway A24 and its connections with Rome´s ring road, managed by Strada dei Parchi SpA. Road pavement data, such as the International Roughness Index (IRI) and the Sideway Force Coefficient (SFC), are integrated into the DT to be analysed through Artificial Intelligence-clustering techniques to perform the sectioning and clustering of road sections according to their status and quality index. The paper shows the benefits derived from the integration of DT technologies with DSTs for improving processes of road maintenance

Tandem Aza-Wittig/Carbodiimide-Mediated Annulation Applicable to 1,2-Diaza-1,3-dienes for the One-Pot Synthesis of Fully Substituted 1,2-Diaminoimidazoles

One-pot sequential aza-Michael, Staudinger, and aza-Wittig reactions on 1,2-diaza-1,2-dienes (DDs) can afford fully substituted 1,2-diaminoimidazoles. A plausible mechanism for the imidazole core formation involving an intramolecular ring closure of the carbodiimide-derived phosphazene intermediate is given. The reported strategy has sufficient flexibility to allow substituted 1,2-diaminoimidazoles with orthogonal nitrogen-protective groups to be generated from a variety of heterocumulene moieties linked to the DDs skeleton