University of Bari Aldo Moro
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Influence of Non-Cross-Linking AGEs on Mechanical Properties and Morphological Features of Tropocollagen Peptides: A Molecular Dynamics Study
No full textCollagen, a protein known for its long lifespan, is susceptible to accumulation of advanced glycation end products (AGEs) with age. These AGEs are considered markers that indicate the aging severity and influence the mechanics of tissues, leading to fragile bones and hardened skin. While many cross-linking AGEs have been widely studied for their ability to reduce the elasticity of biological tissues, contributing to skin hardening and fragile bones, through strong covalent bonds, non-cross-linking AGEs, or AGE adducts, are typically investigated as indicators of aging or as signaling factors in pathological conditions. However, recent experimental findings have revealed that the number of AGE adducts in aged bone is comparable to enzymatic cross-links, which are significantly more abundant than cross-linking AGEs. Based on these observations, we consider one of the most abundant AGE adducts - carboxymethyllysine (CML) - and employ molecular dynamics simulations to explore its direct impact on the mechanical and conformational properties of single tropocollagen molecules. Our models demonstrate that tropocollagen peptides, constructed based on sequences experimentally identified with sites of CML modifications in type I collagen derived from human cortical bone, exhibit heterogeneous behaviors under tensile testing. Still, most of these modified peptides display compromised structural stability, reduction in structural strength, and diminished energy dissipation ability when tension is applied. This study highlights the potential impact of non-cross-linking AGEs on collagen behavior at molecular scale and provides insights into the mechanisms underlying these modifications. Gaining a deeper understanding of the role of AGE adducts and their contribution to the aging process may pave the way for future solutions in antiaging research
In-flight positron annihilation as a probe of feebly interacting particles
No full textCore-collapse supernovae (SNe) provide a unique environment to study feebly interacting particles (FIPs) such as axionlike particles (ALPs), sterile neutrinos, and dark photons (DPs). This paper focuses on heavy FIPs produced in SNe, whose decay produces electrons and positrons, generating observable secondary signals during their propagation and annihilation. We focus on the in-flight annihilation of positrons, which emerge as the most significant contribution to the resulting γ-ray spectrum. Using data from COMPTEL and EGRET, we derive the most stringent bounds on the FIP-electron couplings for heavy ALPs, sterile neutrinos, and DPs. These results strengthen existing bounds by one to two orders of magnitude, depending on the FIP model
Mohsin Hamid's Exit West as a Transmodern Narrative of(f) the Limit
No full textThe purpose of this chapter is to read Mohsin Hamid’s Exit West as a narrative “of(f) the limit” since it illustrates the transmodern sensibility of conceptualising limits as spaces of both negotiation and exclusion. The main narrative thread of the novel centres on a young couple leaving their homeland at risk from war. However, Nadia and Saeed’s plotline is intercut with brief parallel narratives of other people’s stories around the world that share the same thematic concern with migration policy and social alienation as displayed in the main narrative strand. To this end, Hamid resorts to a narrative technique that evokes a sense of instantaneity, reminding us of the simultaneity of time and the interconnectedness among individuals across the planet. In certain respects, this ubiquitous way of envisioning reality is in tune with the main tenets of the transmodern paradigm. Thus, on the one hand, the novel seeks to transgress the limits of Eurocentrism, giving voice to those who are excluded. On the other, by conflating social critique, the use of technology and magic realism, Exit West slides between a realistic depiction and a fantasy tale as characters strive to construct their own identities and negotiate new opportunities
A Systematic Search for MeV–GeV Pulsar Wind Nebulae without Gamma-Ray Detected Pulsars
No full textAn increasing number of pulsar wind nebulae (PWNe) are being identified in the TeV band by ground-based Imaging Air Cherenkov Telescopes such that they constitute the dominant source class of Galactic TeV emitters. However, MeV-GeV PWN counterparts are still largely lacking. To date, only a dozen PWNe are identified by the Fermi-Large Area Telescope (LAT) in the MeV-GeV band. Most PWNe are located along the Galactic plane embedded within the prominent, diffuse Galactic gamma-ray emission, which makes these sources difficult to disentangle from the bright diffuse background. We present a systematic search for gamma-ray counterparts to known PWNe in the 300 MeV-2 TeV energy band using the Fermi-LAT. We target the locations of previously identified PWNe that lack detected Fermi-LAT pulsars to minimize associated pulsar contamination. The sample includes six previously identified Fermi PWNe and eight Fermi-LAT sources associated with PWNe. We report the analysis of 58 regions of interest and classify Fermi-LAT detected sources as either a likely PWN or a candidate PWN counterpart based on their morphological and spectral characteristics across the broadband spectrum. There are nine unidentified Fermi-LAT sources that we consider as likely PWN counterparts, which, if confirmed to be PWNe, would greatly increase the PWN population detected by the Fermi-LAT from 12 to 21. The remaining Fermi-LAT detected sources are considered weaker PWN candidates. A second approach in the systematic search for gamma-ray emitting PWNe will involve studying the off-pulse phases of Fermi-LAT detected pulsars for the presence of an obscured PWN and will be reported in a subsequent paper
Characterization of glycans expressed in the prostate of donkey Equus asinus
No full textThe presence of N- and O-linked glycans as well as fucosylated and sialilatedglycoproteins was investigated in the donkey prostate by lectinhistochemistry. Prostate tissuefragmentswereroutinelyprocessed forhistologicalinvestigation and stained with a panel of twelve HRP-labeledlectins. The cytoplasm of the secretoryepitheliumdidnot express N-linked and fucosylatedglycans, whereasitcontained O-linkedglycans and negativelychargedglycanssuchassialoglycans. The intraluminalcontentlackedα1,3-sialoglycans compared with the epithelium. Thissuggeststhatchanges in the chemicalcomposition of secretory products occur in the lumen of prostate acini. The reduction of negativelychargedglycoproteinscould be involved in fertility of the donkey
Valorisation of grape pomace as source of bioactive compounds in Deep Eutectic Solvents ready-to-use extracts
No full textThe constantly growing global population, predicted to reach up to 11 billion people by 2050, is gradually making agro-industrial waste a serious issue about its contribute to the global environmental pollution. In a recent paper, grape pomace has been found, through HPLC-DAD analysis, antioxidant and antimicrobial assays, to have a great potential about its sustainable re-use as source of polyphenols, which have a significant impact on human health. Starting from these promising findings, seventeen different red and white grape pomaces have been collected for this study from various parts of Apulia (Italy) with the aim to perform green solid-liquid extractions, by using the so-called Deep Eutectic Solvents (DESs). Fourteen selected phenolic compounds’ profile of all the extracts was obtained through chemical analysis performed by HPLC-DAD with a previously developed method. Then, two cultivars, namely Sangiovese and Merlot, which showed a higher phenolic compounds content, were extracted using Betaine/Lactic Acid (1:4 mol/mol + 40% H2O) and Choline Chloride/Ascorbic Acid (2:1 mol/mol + 40% H2O) DESs and were selected for further characterization by LC-ESI-TOF-MS. Sixty-two different phenolic compounds were detected, with extraction yields up to three times higher using Betaine/Lactic Acid compared to Choline Chloride/Ascorbic Acid DES. This trend was confirmed by agar diffusion antimicrobial assays, in which only Betaine/Lactic Acid-based DES extracts showed significant effects. Considering these findings, in vitro digestion was finally performed on these freeze-dried DES extracts obtaining preliminary results about composition and bioactivity in each studied phase. An application of these products as ready-to-use food and/or feed supplements will be discussed
An Overview of Sarcopenia: Focusing on Nutritional Treatment Approaches
Get PDFSarcopenia is a syndrome characterized by the progressive and generalized loss of skeletal muscle mass and strength. This condition is associated with physical disability, decreased quality of life, and increased mortality. Therefore, reducing the prevalence of sarcopenia could significantly lower healthcare costs. Sarcopenia can be classified into primary and secondary sarcopenia. The former is related to aging and begins after the fourth decade of life; after that, there is a muscle loss of around 8% per decade until age 70 years, which subsequently increases to 15% per decade. On the other hand, secondary sarcopenia can affect all individuals and may result from various factors including physical inactivity, malnutrition, endocrine disorders, neurodegenerative diseases, inflammation, and cachexia. Understanding the multiple mechanisms involved in the onset and progression of sarcopenia allows for us to develop strategies that can prevent, treat, or at least mitigate muscle loss caused by increased protein breakdown. One potential treatment of sarcopenia is based on nutritional interventions, including adequate caloric and protein intake and specific nutrients that support muscle health. Such nutrients include natural food rich in whey protein and omega-3 fatty acids as well as nutritional supplements like branched-chain amino acids, β-hydroxy-β-methylbutyrate, and vitamin D along with food for special medical purposes. It is important to emphasize that physical exercises, especially resistance training, not only promote muscle protein synthesis on their own but also work synergistically with nutritional strategies to enhance their effectiveness
Essays on Educational Equality of Opportunity: Methodologies, Resilience, and Gender Disparities
No full textThis dissertation explores the challenges and dynamics of Educational Equality of Opportunity (EEOp) through three interconnected themes: methodologies, academic resilience, and gender disparities. Utilizing quantitative methods, it investigates the mechanisms that contribute to an unequal distribution of educational outcomes and opportunities. The first section reviews the state of the art in EEOp literature, focusing on the principal approaches used to measure it. The second empirically examines innovative methodological frameworks for assessing EEOp, highlighting both their strengths and limitations. The third section delves into the concept of academic resilience, identifying key factors that enable disadvantaged students to overcome educational barriers. Finally, the fourth section addresses gender disparities in educational attainment, analyzing the root causes of these gaps and their implications for future policy interventions. By integrating these perspectives, this dissertation offers a comprehensive analysis of how educational systems can be structured to foster greater fairness and equality
La scultura e l’arte dell’intaglio: modelli, tecniche e materiali nella bottega di Giacomo Colombo (1663-1731). Colombo e la fortuna dei modelli romani
No full textLa cultura artistica di Giacomo Colombo e i modelli iconografici contemporanei: il saggio indaga sul rapporto dello sculture napoletano con i modelli iconografici degli artisti romani, in particolare con i modelli di Duquesno
A MATLAB Code for Handling Efficiently Discontinuous BVPs
No full textThis paper focuses on the HOFiD_bvp code, initially developed by Amodio and Settanni in MATLAB for solving second-order scalar boundary value problems in ordinary differential equations. The objective of this study is to present an enhanced version of the code that can tackle problems involving one or more unknown parameters by incorporating an equivalent number of equations. Furthermore, the upgraded code demonstrates improved capability in efficiently handling discontinuous source terms and solutions. Several numerical experiments are conducted to showcase these novel features