Archivio istituzionale della ricerca - Alma Mater Studiorum Università di Bologna
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Scaling up pullulan-based supercapacitors: A sustainable approach to binder and separator integration in EDLCs
No full textElectrochemical double-layer capacitors (EDLCs) play a critical role in high-power energy storage, offering exceptional durability and longevity for diverse applications. EDLCs typically utilize activated carbon electrodes combined with organic electrolytes, produced through cost-effective roll-to-roll manufacturing, and achieving operating voltages of approximately 2.7 V. Replacing toxic materials in electrode fabrication is critical for transitioning towards sustainable manufacturing practices. A key component in their production is the binder, which must ensure uniform coating, thermal and mechanical stability, optimal microstructural properties, electrochemical inertness, and environmentally friendly processing. Pullulan (PUL), a water-soluble polysaccharide, emerges as a promising alternative, offering reduced environmental impact and cost benefits. Our recent studies demonstrated the feasibility of PUL as a binder for aqueous processed EDLCs at the laboratory-scale. However, scaling up this process and validating it for large-scale EDLC electrodes remain open challenges. Here, we present a comprehensive investigation into the optimization of low-binder-content, high-mass-loading electrode manufacturing at both laboratory and pre-industrial scales. Moreover, a PUL electrospun membrane has been also investigated as separator. The optimized electrode formulations are validated in pouch cells with 20 cm2 electrodes, providing critical insights into the feasibility and scalability of the proposed supercapacitor configuration
Feasibility of Physical Unclonable Function (PUF) Implementation Using the Pull-up/Pull-down Resistances Integrated in Microcontrollers GPIO
No full textSecurity in wireless sensor networks is usually improved by lightweight authentication and data obfuscation approaches. In such wireless networks, authentication passwords and cryptographic keys can be generated at low cost by Physical Unclonable Function (PUF) devices, that exploit the occurrence of random variations in CMOS technology parameters during manufacturing. In this paper, we study the feasibility to implement PUFs by exploiting the pull-up and pull-down resistances integrated in the General Purpose Input Output (GPIO) interface of microcontrollers. For our study, we performed experimental measurements of the considered PUF on five different STM32F103C8T6 microcontrollers, and we derived its PUF performance metrics commonly used in the literature (uniqueness, uniformity, steadiness, reliability to temperature fluctuations and reliability to power supply fluctuations). The results have shown that different groups of microcontroller pins, that are able to tolerate different maximum voltages, can be characterized by significant differences in the values of the pull-up/pull-down resistances and thus on the performance of the designed PUF. The best results have been obtained for the case of the pull-up resistances of 5V tolerant pins, for which we have obtained a uniqueness of 44.92%, a uniformity of 53.31%, a steadiness of a 99.41%, a reliability for temperature fluctuations of 97.57%, and a reliability for power supply fluctuations of 99.84%
Scaling of wall-pressure–velocity correlations in high-Reynolds-number turbulent pipe flow
No full textAn experimental study was conducted in the CICLoPE long-pipe facility to investigate the correlation between wall-pressure and turbulent velocity fluctuations in the logarithmic region, at high friction Reynolds numbers . Hereby, we explore the scalability of employing wall-pressure to effectively estimate off-the-wall velocity states (e.g. to be of use in real-time control of wall-turbulence). Coherence spectra for wall-pressure and streamwise (or wall-normal) velocity fluctuations collapse when plotted against and thus reveals a Reynolds-number-independent scaling with distance-from-the-wall. When the squared wall-pressure fluctuations are considered instead of the linear wall-pressure term, the coherence spectra for the wall-pressure-squared and velocity are higher in amplitude at wavelengths corresponding to large-scale streamwise velocity fluctuations (e.g. at, the coherence value increases from roughly 0.1 up to 0.3). This higher coherence typifies a modulation effect, because low-frequency content is introduced when squaring the wall-pressure time series. Finally, quadratic stochastic estimation is employed to estimate turbulent velocity fluctuations from the wall-pressure time series only. For each investigated, the estimated time series and a true temporal measurement of velocity inside the turbulent pipe flow yield a normalised correlation coefficient of for all cases. This suggests that wall-pressure sensing can be employed for meaningful estimation of off-the-wall velocity fluctuations and thus for real-time control of energetic turbulent velocity fluctuations at high- applications
Ptychographic analysis of human bone marrow‐derived mesenchymal stem cell morphology: The impact of cell senescence
No full textMesenchymal stem cells (MSC) undergo replicative senescence, a state of irreversible cell cycle arrest that limits their utility in regenerative medicine applications. To identify novel markers of senescence useful to enhance the quality of MSC-based therapies, we compared young and senescent human bone marrow-derived mesenchymal stem cells (hMSCs) using a non-invasive, label-free approach based on quantitative phase imaging (QPI) with the Livecyte microscope. Senescent hMSCs demonstrated substantial morphological alterations, including a threefold increase in cell area, elevated dry mass, reduced thickness, and decreased sphericity compared to their younger counterparts. Additionally, motility metrics such as instantaneous velocity and displacement were significantly reduced in senescent cells, underscoring functional impairments that could hinder their therapeutic potential in regenerative medicine. The application of QPI offers a promising tool for monitoring cellular health, identifying, and potentially eliminating, senescent cells to improve the quality and effectiveness of MSC-based therapies
Comparison of prestroke frailty and disability for outcome prediction in older stroke patients
No full textBackground: Prestroke disability, measured by the modified Rankin Scale (mRS), is routinely used in older (≥65 years) patients to predict stroke outcomes. Frailty, a common geriatric syndrome, is also associated with poor health outcomes but is rarely assessed in older stroke patients. The Clinical Frailty Scale (CFS) is a simple frailty assessment tool; however, its prognostic value in stroke clinical practice remains uncertain. This study compares the predictive value of prestroke mRS and CFS for stroke outcomes in older patients. Methods: We included 4086 older patients with acute stroke (82.6 % ischemic), consecutively admitted to an Italian hospital. The median age was 81 years (25th–75th percentile: 75–87 years). Prestroke mRS was assessed at admission, while prestroke CFS was retrospectively evaluated from medical records. Multivariable-adjusted models tested the association of each scale with prolonged admission, unfavorable discharge setting, and mortality at 30 days and 1 year. For each outcome, the predictive value of the mRS and CFS scales was compared using the difference in Akaike's Information Criterion (AIC) between the respective models (AICmRS-CFS). Results: Both mRS and CFS were positively associated with unfavorable discharge and mortality and inversely associated with prolonged admission. However, based on AICmRS-CFS, CFS was a stronger outcome predictor than mRS. In ischemic stroke patients receiving reperfusion therapies, CFS was also superior to mRS in predicting neurological improvement following treatment and the likelihood of discharge to long-term care. Conclusions: Compared to prestroke mRS, prestroke CFS may offer additional prognostic information in older stroke patients
Copernicus for monitoring European forests: strengths, challenges and potential
No full textCopernicus is the European Union’s Earth Observation program, offering forest-related maps through its High-Resolution Layers (HRL). Corine Land Cover (CLC) and the Japan Aerospace Exploration Agency (JAXA) also provide map-based products on European forests. However, these maps are difficult to use due to the lack of aggregated statistics, and their consistency with official forest statistics from national forest inventories compiled by the Food and Agriculture Organisation (FAO) remains unclear. This study explores the potential of Copernicus ready-to-use data for simplified forest statistics, temporal consistency, and alignment with external and validation sources. First, Copernicus data were integrated with European Local Administrative Units (LAUs) to produce comprehensive information on forest cover and density at the local scale. Second, forest area estimates from HRL, CLC, and JAXA pixel counts were compared with FAO statistics at the country level. Results indicate that changes in methodologies and spatial resolution of the source data used in Copernicus HRL over the past decade affect the reported statistics. Copernicus HRL data show significant discrepancies compared to FAO data, while JAXA and CLC data are more aligned. These findings highlight the need to integrate better, present, and homogenize European forest information tools to ensure practical and accessible data
Unveiling the nature of electronic transitions in RbV3Sb5 with avoided level crossing μSR
No full textLayered kagome metals AV3Sb5 provide a unique platform for studying the interplay between a variety of electronic orders, including superconductivity, charge density waves, nematic phases, and more. Understanding the evolution of the electronic state from the charge density wave to the superconducting transition is essential for unraveling the interplay of charge, spin, and lattice degrees of freedom giving rise to the unusual magnetic properties of these nonmagnetic metals. Previous zero-field and high-field muon spin relaxation (μSR) studies revealed two anomalies in the muon spin relaxation rate, a first change at TCDW∼100K and a second steep increase at T*∼40K, further enhanced by an applied magnetic field, thus suggesting a contribution of magnetic origin. In this Letter, we use the avoided level crossing μSR technique to investigate charge order in near-zero applied field. By tracking the temperature dependence of quadrupolar level-crossing resonances, we examined the evolution of the electric field gradient at V nuclei in the kagome plane. Our results show a significant rearrangement of the charge density starting at T* indicating a transition in the charge distribution, likely electronic in origin, well below TCDW. These findings, combined with previous μSR, scanning tunneling microscopy, and nuclear magnetic resonance (NMR) studies, emphasize the intertwined nature of proximate phases in these systems, with the charge rearrangement dominating the additional increase in μSR relaxation rate below T*
The Logic of Brokerage: Why Interest Organizations Network with Their Opponents
No full textCooperation in lobbying is central to policymaking, and the formation of coalitions is a frequently used strategy by interest groups seeking to influence policy outcomes. While coalition formation between like-minded organizations is well documented, the literature has so far overlooked interest groups networking with groups that pursue opposed policy goals. In this article, we advance a novel theoretical proposition to explain an interest group’s propensity to network with its political opponents based on the logic of brokerage. We argue that brokers between opposing policy positions can secure long-term advantages as political insiders across diverse issues, but risk damaging their reputation and alienating their members. We test our argument empirically based on survey data for roughly 2000 interest groups in 7 European countries. Our findings give robust support to our theoretical framework and shed new light on lobbying strategies and the logics that drive cooperation in lobbying, de-escalation, and access to policymaking
Cyclodextrin-Modified Capillary Zone Electrophoresis for the Chiral Analysis of Proline and Hydroxyproline Stereoisomers in Chicken Collagen Hydrolysates
No full textThe stability of collagen, the most abundant protein in humans and many animals, is related to the hydroxylation of L-proline, a post-translational modification occurring at carbon 3 and 4 on its pyrrolidine ring. Collagens of different origins have shown different proline hydroxylation levels, making hydroxyprolines useful biomarkers in structure characterizations. The presence of two chiral carbon atoms, 3-hydroxyproline and 4-hydroxyproline, results in eight stereoisomers (four pairs of enantiomers) whose quantitation in collagen hydrolysates requires enantioselective analytical methods. Capillary electrophoresis was applied for the separation and quantitation of the eight stereoisomers of 3- and 4-hydroxyproline and D,L-proline in collagen hydrolysates. The developed method is based on the derivatization with the chiral reagent (R)-(-)-4-(3-Isothiocyanatopyrrolidin-yl)-7-nitro-2,1,3-benzoxadiazole, enabling the use of a light-emitting diode-induced fluorescence detector for high sensitivity. The separation of the considered compounds was accomplished in less than 10 min, using a 500 mM acetate buffer pH 3.5 supplemented with 5 mM of heptakis(2,6-di-O-methyl)-beta-cyclodextrin as the chiral selector. The method was fully validated and showed the adequate sensitivity for the application to samples of collagen hydrolysates. The analysis of samples extracted from chicken Pectoralis major muscles affected by growth-related myopathies showed different stereoisomer patterns compared to those from the unaffected control samples
Anarchie
No full textBien que considérée, encore de nos jours, comme étant synonyme de « chaos » ou désorganisation, l’anarchie a pourtant été définie, en 1851, comme « la plus haute expression de l’ordre ». L’auteur de cette définition, Élisée Reclus (1830-1905), a certainement été inspiré par des formulations que l’on trouve chez Proudhon (« la plus haute perfection de la société se trouve dans l’union de l’ordre et de l’anarchie », 1840) ou chez Bellegarrigue (avec son manifeste publié dans L’Anarchie, journal de l’ordre, 1850). Reclus est aussi, avec son ami et collaborateur Pierre Kropotkine (1842-1921), l’un des fondateurs de la géographie moderne ainsi que du mouvement anarchiste international (Brun 2022). Cette relation n’est pas anodine car il existe un double lien entre géographie et anarchie : le premier, historique et matériel, le deuxième, conceptuel