138 research outputs found

    Social Bonds and the “Social Premium”

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    Although Social bonds (SB) have witnessed an unprecedented increase especially since the outburst of the Covid-19 pandemics, their performance vs. conventional bonds (CB) has not attracted much attention. The aim of this paper is to test the existence, the sign and the determinants of a “social premium”, defined as the yield differential between a SB and an otherwise identical CB. To this end we set up a sample of 64 SB aligned with ICMA (International Capital Market Association) principles and 64 matched CB, from October 2020 to October 2021 so as to focus on the peak of SB issuances. We run regressions based on the idea that daily yield differential between SB and CB may be determined by differences in un-matched characteristics. Based on the FE specification, which turns out to be preferred vs. OLS and RE, a few main results emerge. First, as for the determinants, the difference in liquidity and in volatility turn out to be significant: they are, respectively, negatively and positively correlated with the yield differential. Second, on the whole sample the analysis of the fixed effects, which represent the social premium, proves the existence of a significantly positive social premium (1.242 bps). This result is robust to outliers, but differences emerge on subsamples. Overall, the small magnitude of the social premium emerging from our analysis over the latter two years would point to a (perhaps more mature) phase of the SB market, whereby the social feature does not make otherwise comparable bonds any different in terms of yiel

    Ultra-Rare Variants Identify Biological Pathways and Candidate Genes in the Pathobiology of Non-Syndromic Cleft Palate Only

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    : In recent decades, many efforts have been made to elucidate the genetic causes of non-syndromic cleft palate (nsCPO), a complex congenital disease caused by the interaction of several genetic and environmental factors. Since genome-wide association studies have evidenced a minor contribution of common polymorphisms in nsCPO inheritance, we used whole exome sequencing data to explore the role of ultra-rare variants in this study. In a cohort of 35 nsCPO cases and 38 controls, we performed a gene set enrichment analysis (GSEA) and a hypergeometric test for assessing significant overlap between genes implicated in nsCPO pathobiology and genes enriched in ultra-rare variants in our cohort. GSEA highlighted an enrichment of ultra-rare variants in genes principally belonging to cytoskeletal protein binding pathway (Probability Density Function corrected p-value = 1.57 Ă— 10-4); protein-containing complex binding pathway (p-value = 1.06 Ă— 10-2); cell adhesion molecule binding pathway (p-value = 1.24 Ă— 10-2); ECM-receptor interaction pathway (p-value = 1.69 Ă— 10-2); and in the Integrin signaling pathway (p-value = 1.28 Ă— 10-2). Two genes implicated in nsCPO pathobiology, namely COL2A1 and GLI3, ranked among the genes (n = 34) with nominal enrichment in the ultra-rare variant collapsing analysis (Fisher's exact test p-value < 0.05). These genes were also part of an independent list of genes highly relevant to nsCPO biology (n = 25). Significant overlap between the two sets of genes (hypergeometric test p-value = 5.86 Ă— 10-3) indicated that enriched genes are likely to be implicated in physiological palate development and/or the pathological processes of oral clefting. In conclusion, ultra-rare variants collectively impinge on biological pathways crucial to nsCPO pathobiology and point to candidate genes that may contribute to the individual risk of disease. Sequencing can be an effective approach to identify candidate genes and pathways for nsCPO

    Effetto del trattamento a vapore sulla resistenza a corrosione di componenti in acciaio sinterizzato

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    Scopo della ricerca è valutare la reale efficacia del trattamento a vapore nel migliorare la resistenza a corrosione di componenti industriali ferrosi sinterizzati. Il presente lavoro riporta i primi risultati relativi a teste di pistone per compressori da frigo sinterizzati, in lega Fe-C a microstruttura ferritico-perlitica. I materiali e le superfici sono stati caratterizzati mediante microscopia ottica ed elettronica a scansione, analisi d’immagine, microanalisi EDXS, misura della densità e della porosità, diffrazione a raggi X. La resistenza a corrosione è stata valutata mediante prove potenziostatiche e potenziodinamiche in cloruro di sodio 0.05M e acido solforico 0.05M, prove di resistenza a polarizzazione, prove per perdita di massa in soluzioni di acido solforico a diluizione crescente e prove in nebbia salina secondo la normativa ISO 9227 (1990). I test sono stati effettuati in parallelo sui componenti sinterizzati e su quelli trattati a vapore. La caratterizzazione elettrochimica ha mostrato un miglioramento della resistenza a corrosione del trattato a vapore, rispetto al materiale sinterizzato, in soluzione di cloruro mentre in acido solforico i due materiali si comportano pressoché allo stesso modo. Tuttavia le prove per perdita di massa in acido solforico hanno evidenziato un miglior comportamento del trattato a vapore dopo il primo giorno di immersione. La caratterizzazione delle superfici dei campioni provati concorda con l’ipotesi che le scarse proprietà iniziali di resistenza a corrosione siano dovute essenzialmente all’ematite presente. Una volta che lo strato chimicamente debole viene rimosso emergono le buone proprietà della magnetite. Le prove in nebbia salina hanno confermato un minor attacco della superficie del componente dopo ossidazione

    SVILUPPO DELL’ATTIVITÀ METALLURGICA IN LIGURIA: IL FERRO IN VALLE STURA DAL XIV AL XVIII SECOLO

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    Molteplici sono i resti che testimoniano le attività siderurgiche nelle valli Stura e Orba e si può individuare in Rossiglione una sorta di “capitale del ferro” della Repubblica di Genova tra il XIV e il XVIII secolo. I numerosi manufatti derivanti dalle intense attività di produzione che hanno caratterizzato i secoli scorsi sono in parte ancora in opera (soprattutto catene murarie, chiavi di volta, chiodature, ed altro materiale di carpenteria che non è mai stato rimosso dalla sua posizione funzionale dal momento della costruzione di un edificio), in parte sono raccolti al museo del ferro di Masone (si va da attrezzi agricoli e artigianali in genere, utensili d’impiego quotidiano, manufatti più umili ma non per questo meno importanti come chiodi, vergelle e simili). Lo studio ha riguardato una scoria, un chiodo, un punteruolo, un attizzatoio, un bolzone e una catena da muro provenienti da prelievi fatti su aree abitate e la cui collocazione storica si spande tra il XVI e il XVIII secolo. Questi reperti sono stati caratterizzati mediante microscopia ottica ed elettronica, microanalisi tramite microsonda in dispersione di energia e in dispersione di lunghezza d’onda. I risultati raccolti hanno permesso di determinare la composizione, la microstruttura, la natura di inclusioni e scorie. L’elaborazione dei dati ottenuti ha fornito informazioni relativamente alla coerenza del pezzo con il periodo cui era stato attribuito e, attraverso la presenza di oligoelementi, la definizione del materiale di partenza, l’individuazione delle metodologie del processo di lavorazione del metallo: dal processo di scorificazione e sbozzatura alla saldatura tramite forgia (bollitura) fino alla rifinitura

    Acciaio sinterizzato trattato a vapore: Caratteristiche e propriet\ue0 degli strati ossidati

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    Nella metallurgia delle polveri le finalit\ue0 del trattamento a vapore possono essere diverse: dall\u2019aumento della durezza, e conseguentemente della resistenza all\u2019usura da strisciamento, all\u2019aumento della massa volumica, all\u2019impermeabilizzazione ai fluidi tramite occlusione della porosit\ue0 intercomunicante. Il risultato tecnologico del trattamento di ossidazione a vapore dipende dai parametri di processo ma anche dalla natura e dalle caratteristiche del materiale trattato, in particolare dalla sua composizione e massa volumica. La ricerca qui presentata \ue8 volta alla caratterizzazione chimica, fisica, morfologica e strutturale dello strato ossidato ottenuto trattando a vapore, in condizioni industriali, un acciaio ferritico sinterizzato con aggiunta di MnS. Tra le diverse tecniche di indagine utilizzate particolare importanza ha avuto la microspettroscopia Raman di cui si \ue8 riscontrata l\u2019efficacia per questa particolare applicazione. Lo strato ossidato sviluppatosi a seguito del trattamento di vaporizzazione, sia sulla superficie esterna sia all\u2019interno delle porosit\ue0 di tutto il componente, \ue8 risultato costituito prevalentemente da magnetite. Lo strato superficiale, nella sua parte pi\uf9 esterna, \ue8 costituito da ematite mescolata a porzioni variabili di magnetite. Negli strati ossidati interni alle porosit\ue0 si \ue8 identificata la presenza di solfuro di ferro circondato da aree di magnetite contenenti piccole percentuali di zolfo e manganese. I risultati esposti in questo lavoro costituiscono un punto di partenza per la valutazione degli effetti del trattamento a vapore sulla resistenza alla corrosione

    Phytotherapeutic effects of Echinacea purpurea in gamma-irradiated mice

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    Echinacea (E.) purpurea herb is commonly known as the purple coneflower, red sunflower and rudbeckia. In this paper, we report the curative efficacy of an Echinacea extract in Îł-irradiated mice. E. purpurea was given to male mice that were divided into five groups (control, treated, irradiated, treated before irradiation & treated after irradiation) at a dose of 30 mg/kg body weight for 2 weeks before and after irradiation with 3 Gy of Îł-rays. The results reflected the detrimental reduction effects of Îł-rays on peripheral blood hemoglobin and the levels of red blood cells, differential white blood cells, and bone marrow cells. The thiobarbituric acid-reactive substances (TBARs) level, Superoxide dismutase (SOD) and glutathione peroxidase (GSPx) activities and DNA fragmentation were also investigated. FT-Raman spectroscopy was used to explore the structural changes in liver tissues. Significant changes were observed in the microenvironment of the major constituents, including tyrosine and protein secondary structures. E. purpurea administration significantly ameliorated all estimated parameters. The radio-protection effectiveness was similar to the radio-recovery curativeness in comparison to the control group in most of the tested parameters. The radio-protection efficiency was greater than the radio-recovery in hemoglobin level during the first two weeks, in lymphoid cell count and TBARs level at the fourth week and in SOD activity during the first two weeks, as compared to the levels of these parameters in the control group

    Profiling of Flavonol Derivatives for the Development of Antitrypanosomatidic Drugs

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    Flavonoids represent a potential source of new antitrypanosomatidic leads. Starting from a library of natural products, we combined target-based screening on pteridine reductase 1 with phenotypic screening on Trypanosoma brucei for hit identification. Flavonols were identified as hits, and a library of 16 derivatives was synthesized. Twelve compounds showed EC50 values against T. brucei below 10 \u3bcM. Four X-ray crystal structures and docking studies explained the observed structure-activity relationships. Compound 2 (3,6-dihydroxy-2-(3-hydroxyphenyl)-4H-chromen-4-one) was selected for pharmacokinetic studies. Encapsulation of compound 2 in PLGA nanoparticles or cyclodextrins resulted in lower in vitro toxicity when compared to the free compound. Combination studies with methotrexate revealed that compound 13 (3-hydroxy-6-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one) has the highest synergistic effect at concentration of 1.3 \u3bcM, 11.7-fold dose reduction index and no toxicity toward host cells. Our results provide the basis for further chemical modifications aimed at identifying novel antitrypanosomatidic agents showing higher potency toward PTR1 and increased metabolic stability

    Lactic acid fermentation as a tool to enhance the antioxidant properties of Myrtus communis berries

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    Background: Myrtle (Myrtus communis L.) is a medicinal and aromatic plant belonging to Myrtaceae family, which is largely diffused in the Mediterranean areas and mainly cultivated in Tunisia and Italy. To the best of our knowledge, no studies have already considered the use of the lactic acid fermentation to enhance the functional features of M. communis. This study aimed at using a selected lactic acid bacterium for increasing the antioxidant features of myrtle berries, with the perspective of producing a functional ingredient, dietary supplement or pharmaceutical preparation. The antioxidant activity was preliminarily evaluated through in vitro assays, further confirmed through ex vivo analysis on murine fibroblasts, and the profile of phenol compounds was characterized. Results: Myrtle berries homogenate, containing yeast extract (0.4%, wt/vol), was fermented with Lactobacillus plantarum C2, previously selected from plant matrix. Chemically acidified homogenate, without bacterial inoculum and incubated under the same conditions, was used as the control. Compared to the control, fermented myrtle homogenate exhibited a marked antioxidant activity in vitro. The radical scavenging activity towards DPPH increased by 30%, and the inhibition of linoleic acid peroxidation was twice. The increased antioxidant activity was confirmed using Balb 3 T3 mouse fibroblasts, after inducing oxidative stress, and determining cell viability and radical scavenging activity through MTT and DCFH-DA assays, respectively. The lactic acid fermentation allowed increased concentrations of total phenols, flavonoids and anthocyanins, which were 5–10 times higher than those found for the non-fermented and chemically acidified control. As shown by HPLC analysis, the main increases were found for gallic and ellagic acids, and flavonols (myricetin and quercetin). The release of these antioxidant compounds would be strictly related to the esterase activities of L. plantarum. Conclusions: The lactic acid fermentation of myrtle berries is a suitable tool for novel applications as functional food dietary supplements or pharmaceutical preparations
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