Italian National Research Council

This review analyzes the evolution, applications, and future prospects of the hollow fiber compression technique, a pivotal advancement in ultrafast laser technology. Over the past three decades, this technique has emerged as a cornerstone, proving instrumental in the generation of few-cycle pulses characterized by millijoule-level energy, spanning a wide spectral range from ultraviolet to mid-infrared wavelengths. Its versatility and efficiency have found applications in diverse scientific disciplines, ranging from attosecond science to extreme nonlinear optics. The review delves into the historical development of the hollow fiber compression technique, highlighting key milestones and technological breakthroughs that have contributed to its current status. The widespread adoption of this technique in laboratories on a global scale is investigated, and an exploration is conducted into the continuously reported innovative experimental implementations. The impact of this technique on attosecond science is scrutinized, emphasizing its role in the generation and application of isolated attosecond pulses.

Extracellular vesicles (EVs) are released by all cells and contribute to cell‐to‐cell communication. The capacity of EVs to target specific cells and to efficiently deliver a composite profile of functional molecules have led researchers around the world to hypothesize their potential as therapeutics. While studies of EV treatment in animal models are numerous, their actual clinical benefit in humans has more slowly started to be tested. In this scoping review, we searched PubMed and other databases up to 31 December 2023 and, starting from 13,567 records, we selected 40 pertinent published studies testing EVs as therapeutics in humans. The analysis of those 40 studies shows that they are all small pilot trials with a large heterogeneity in terms of administration route and target disease. Moreover, the absence of a placebo control in most of the studies, the predominant local application of EV formulations and the inconsistent administration dose metric still impede comparison across studies and firm conclusions about EV safety and efficacy. On the other hand, the recording of some promising outcomes strongly calls out for well‐designed larger studies to test EVs as an alternative approach to treat human diseases with no or few therapeutic options.

Perovskite solar cells, known for high efficiency and compatibility with various photovoltaic (PV) applications, have garnered significant attention from academia and industry. Scaling up these cells conventionally involves fabricating modules with series‐connected cells using a monolithic interconnection based on the P1‐P2‐P3 scheme, a common approach for thin‐film PV modules. The Geometrical Fill Factor (GFF), representing the ratio between active area and aperture area, typically ranges from 90% to 95%. This study introduces an advanced laser manufacturing process to minimize interconnection area by reducing scribe width and minimizing distances between them, achieving an interconnection width of 45 µm with a GFF of 99.1%. Additionally, a discontinuous P2 design further reduces the dead area to an average of 19.5 µm, resulting in a record GFF of 99.6%. Using this interconnection in a highly efficient p‐i‐n stack, the study demonstrates the feasibility of the discontinuous P2 by fabricating 2.6 cm² minimodules with an aperture area efficiency of 20.7%. The research highlights how proper design can minimize intrinsic losses during the scaling process from cell to module to a negligible level. Experimental studies, coupled with cell‐to‐module loss simulations and electroluminescence mapping for layer deposition uniformity, provide insights into the potential of the new P2 design.

In this article, the diffusion Monte Carlo (DMC) method is applied to the study of the quantum states of a hydrogen atom confined into a cylindrical potential well. We present an independent reproduction of previous studies based on different methods, in particular the energy eigenvalues for ground and selected excited states and the polarizability of the ground state, both for finite and infinite cylinders. The static field ionization of ground and excited states of the confined atom is discussed, including the determination of the potential energy surface and equilibrium position of the proton. This study provides a further demonstration of the versatility of the DMC method for this and analogous problems.

The conditions of the burial environment trigger microstructural modifications and physical‐chemical changes in the bone, such as chemical dissolution, increase of crystallinity, chemical exchanges, collagen degradation and changes in porosity, hence to reproduce these patterns is a challenging task. This work presents a new method to accelerate the diagenetic processes in the laboratory. Artificial aging is obtained by immersion at 80°C in “enriched” solutions derived from the leaching of gravesoils, maintaining the same pH, for 1 month, on modern bones collected from an autopsy. Two distinct solutions from two graves of the necropolis of Travo (IT) (7th–8th century AD) were adopted. The induced damage patterns, on the bone microstructure and the organo‐mineral fraction, have been compared with those observed on buried skeletal elements from the same graves, by providing a multi‐analytical approach (BSE‐SEM, EMPA, FT‐IR, MP‐AES). Bioapatite parameters, such as crystallinity index and Ca/P molar ratio, evolved similarly and, in some cases, reached the same values of buried bones. Conversely, in the absence of microbial activity, the organic fraction better survived the artificial aging. For the same reason, the porosity due to bioerosion was absent in the artificially aged samples, whereas the biological pores and the post‐mortem fractures exhibited the same histomorphology. It is believed that the opportunity of reproducing the diagenetic changes by replicating the chemical environment of the burial site at the laboratory scale is of great interest to forensic science and archaeology (e.g., to reconstruct the burial environment).

An eutectic mixture of tetrabutylammonium bromide and octanol in the molar ratio 1‐10 exhibited a melting point of ‐17°C. This system was investigated by means of infrared spectroscopy, in the liquid and in the solid state. Classical molecular dynamics was performed to study the fine details of the hydrogen bond interactions established in the mixture. Both octanol and the mixtures displayed an almost featureless far‐infrared spectrum in the liquid state but it becomes highly structured in the solid phase. DFT calculations suggest that new vibrational modes appearing in the mixture at low temperatures may be related to the population of the higher energy conformers of the alcohol. Mid‐infrared spectroscopy measurements evidenced no shift of the CH stretching bands in the mixture compared to the starting materials, while the OH stretching are blue shifted by a few cm‐1. Consistently, molecular dynamics provides a picture of the mixture in which the hydrogen bonds (HB) of pure octanol are replaced by weaker HB formed with the TBA ion and the Br cation. Due to these interactions the ionic couple becomes more separated. In agreement with this model, the lengths of all HB are much larger than those observed in acids in previous studies.

The absorption and emission spectral shapes of a flexible organic probe, the distyrylbenzene (DSB) dye, are simulated accounting for the effect of different environments of increasing complexity, ranging from a homogeneous, low‐molecular‐weight solvent, to a long‐chain alkane, and, eventually, a channel‐forming organic matrix. Each embedding is treated explicitly, adopting a mixed quantum‐classical approach, the Adiabatic Molecular Dynamics ‐‐ generalized vertical Hessian (Ad‐MD|gVH) model, which allows a direct simulation of the environment‐induced constraining effects on the vibronic spectral shapes. In such a theoretical framework, the stiff modes of the dye are described at a quantum level within the harmonic approximation, including Duschinsky mixing effects, while flexible degrees of freedom of the solute (e.g. torsions) and those of the solvent are treated classically by means of molecular dynamics sampling. Such a setup is shown to reproduce the distinct effects exerted by the different environments in varied thermodynamic conditions. Besides allowing for a first‐principles rationale on the supramolecular mechanism leading to the experimental spectral features, this result represents the first successful application of the Ad‐MD|gVH method to complex embeddings and supports its potential application to other heterogeneous environments, such as for instance pigment‐protein complexes or organic dyes adsorbed into metal‐organic frameworks.

Blistering is a phenomenon sometimes observed in sputtered-deposited thin films but seldom investigated in detail. Here, we consider the case of titania-doped germania (TGO)/silica multilayers deposited by ion beam sputtering. TGO is a candidate as high refractive index material in the Bragg mirrors for the next iteration of gravitational waves detectors. It needs to be annealed at 600 ∘C for 100 h in order to reach the desired relaxation state. However under some growth conditions, in 52-layer TGO/silica stacks, blistering occurs upon annealing at a temperature near 500 ∘C, which corresponds to the temperature where Ar desorbs from TGO. In order to better understand the blistering phenomenon, we measure the Ar transport in single layers of TGO and silica. In the case of < 1 µm-thick TGO layers, the Ar desorption is mainly limited by detrapping. The transport model also correctly predicts the evolution of the total amount of Ar in a 8.5 µm stack of TGO and silica layers annealed at 450 ∘C, but in that case, the process is mainly limited by diffusion. Since Ar diffusion is an order of magnitude slower in TGO compared to silica, we observe a correspondingly strong accumulation of Ar in TGO. The Ar transport model is used to explain some regimes of the blisters growth, and we find indications that Ar accumulation is a driver for their growth in general, but the blisters nucleation remains a complex phenomenon influenced by several other factors including stress, substrate roughness, and impurities.

This chapter is devoted to polyelectrolytes (PEs), which possess macromolecules with a substantial part comprised of ionic or ionizable functional groups. Solutions of PEs reveal non-trivial physical phenomena when such functional groups are ionized under dissociation of counterions. Accordingly, electrostatic interactions between PE charges and dissociated counterions in solution, or in complex with another PE suspended in the same electrolyte reveal unexpected and attractive properties. As a result, conformations and dynamics of such PEs in solution are significantly affected by electrostatic interactions with the other PEs of the same or an opposite polarity. Especially interesting for applications are macromolecular polyelectrolyte complexes (PECs) resulting from the association of oppositely charged PEs. Polyelectrolytes can be electrospun to form nanofibers and nanofiber membranes. Electrospinning of polyelectrolytes is described here in detail, including the unusual physical properties of the resulting nanofibers and their internal structure. The deformable polyelectrolyte fibrous membranes can sustain an electro-osmotic throughflow and serve as a key element of artificial dynamically-tunable responsive malleable surfaces of the type of those considered in Sect. 1.3.6 in Chap. 1.

The six topics covered in the present chapter stem from recent applications of nanofibers in novel materials and devices. (i) Self-healing vascular nanotextured materials incorporate nanofibers filled with healing agents. When a material like that is damaged, the healing agents are released and polymerize spanning cracks and reparing engineering materials in situ, similarly to living tissues. (ii) Biopolymer-derived nanofibers can be formed from bio-waste, while serve in important novel biomedical and agricultural applications, as well as sophisticated filter media. The additional benefits of such nanotextured materials are in their biocompatibility and biodegradability. (iii) Nanofibers are also involved in thermo-pneumatic soft robots and actuators, which were recently developed. (iv) Biopolymer-derived nanofibers reveal significant triboelectric properties and thus, can be used as triboelectric nanogenerators. On the other hand, superhydrophobic electrospun fibrous membranes comprise an attractive venue for development of novel fabrics. (v) Nanofibers can be electroplated or sputter-coated, which leads to multiple novel applications, e.g., as nanotextured heaters, sensors, or highly effective electrostatic filters. (vi) Several additional physical properties, which can be incorporated in nanofibers include ferroelectricity, flexoelectricity and piezoelectricity, which can be employed in such devices as nanotextured wave-energy harvesters. Nanofibers can also be formed from conducting polymers and used in transparent fibrous heaters.

This chapter presents an overview of the biomedical applications of electrospun nanofibers. Due to the impact of novel technological advancements on nanoplatform fabrication, this well-explored topic is still one of the most dynamic and exciting biomedically-oriented scientific fields. The entire chapter comprises three sections dealing with different applications of nanofibers linked by a shared element, which is the vital role of the nanostructure for the functional properties of the fibrous biomaterials under discussion. The first section introduces the key contribution of electrospun nanomaterials in developing injectable biomaterials for targeted nanomedicine. The second section reviews the interaction between fibrous hemostatic agents fabricated via electrospinning and blood, starting from basic principles to the final clinical applications. The last section is entirely focused on one of the most timely topics, such as the fabrication of innovative face masks. The evolution of face mask development is discussed in order to pave the way for providing an overview of the most challenging aspect of the fabrication of the next generation of face masks characterized by multifunctionality and the possibility to activate them on demand.

Fluid flows coupled with electrical phenomena represent a fascinating and highly interdisciplinary scientific field. Recently, a remarkable success of electrospinning in producing polymer nanofibers has led to extensive research aimed at understanding the behavior of viscoelastic jets affected by the applied electric and aerodynamic forces, such as those imposed by the surrounding gas flows. Theoretical models have uncovered various unique aspects of the underlying physics of polymer solutions in these jets, offering valuable insights for experimental platforms. This chapter explores the progress made in the theoretical description and numerical simulations of polymer solution jets in electrospinning. It emphasizes the instability phenomena arising from both electric and hydrodynamic factors, which are pivotal for understanding the flow physics. The chapter also outlines specifications for creating accurate and computationally feasible models. Topics covered include electrohydrodynamic modeling, theories describing jet bending instability, recent advancements in Lagrangian approaches for jet flow description, strategies for dynamic refinement of simulations, and the effects of intense elongational flow on polymer networks. In addition, the present chapter discusses current challenges and future prospects in this field, which encompasses the physics of jet flows, non-trivial material properties, and the development of multiscale techniques for modeling viscoelastic jets.

Purpose To investigate the feasibility of an artificial intelligence (AI)-based semi-automated segmentation for the extraction of ultrasound (US)-derived radiomics features in the characterization of focal breast lesions (FBLs). Material and methods Two expert radiologists classified according to US BI-RADS criteria 352 FBLs detected in 352 patients (237 at Center A and 115 at Center B). An AI-based semi-automated segmentation was used to build a machine learning (ML) model on the basis of B-mode US of 237 images (center A) and then validated on an external cohort of B-mode US images of 115 patients (Center B). Results A total of 202 of 352 (57.4%) FBLs were benign, and 150 of 352 (42.6%) were malignant. The AI-based semi-automated segmentation achieved a success rate of 95.7% for one reviewer and 96% for the other, without significant difference ( p = 0.839). A total of 15 (4.3%) and 14 (4%) of 352 semi-automated segmentations were not accepted due to posterior acoustic shadowing at B-Mode US and 13 and 10 of them corresponded to malignant lesions, respectively. In the validation cohort, the characterization made by the expert radiologist yielded values of sensitivity, specificity, PPV and NPV of 0.933, 0.9, 0.857, 0.955, respectively. The ML model obtained values of sensitivity, specificity, PPV and NPV of 0.544, 0.6, 0.416, 0.628, respectively. The combined assessment of radiologists and ML model yielded values of sensitivity, specificity, PPV and NPV of 0.756, 0.928, 0.872, 0.855, respectively. Conclusion AI-based semi-automated segmentation is feasible, allowing an instantaneous and reproducible extraction of US-derived radiomics features of FBLs. The combination of radiomics and US BI-RADS classification led to a potential decrease of unnecessary biopsy but at the expense of a not negligible increase of potentially missed cancers.

We investigate for the first time the compatibility of nanovials with microfluidic impedance cytometry (MIC). Nanovials are suspendable crescent-shaped single-cell microcarriers that enable specific cell adhesion, the creation of compartments...

Pancreatic β-cell dysfunction is a key feature of type 2 diabetes, and novel regulators of insulin secretion are desirable. Here we report that the succinate receptor (SUCNR1) is expressed in β-cells and is up-regulated in hyperglycemic states in mice and humans. We found that succinate acts as a hormone-like metabolite and stimulates insulin secretion via a SUCNR1-Gq-PKC-dependent mechanism in human β-cells. Mice with β-cell-specific Sucnr1 deficiency exhibit impaired glucose tolerance and insulin secretion on a high-fat diet, indicating that SUCNR1 is essential for preserving insulin secretion in diet-induced insulin resistance. Patients with impaired glucose tolerance show an enhanced nutritional-related succinate response, which correlates with the potentiation of insulin secretion during intravenous glucose administration. These data demonstrate that the succinate/SUCNR1 axis is activated by high glucose and identify a GPCR-mediated amplifying pathway for insulin secretion relevant to the hyperinsulinemia of prediabetic states.