135 research outputs found

    energy related catalysis

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    by addition of alkali metals as promoters [13] Adding alkali(oxides) to the surface of a transition-metal induces local electrical fields.This allows one to exploit the fact that the N2 dissociation transition state has a larger dipole moment than adsorbed N. Therefore, the scaling relation line in Fig. 1a is shifted downwards resulting in a circumvention of the pure-metal scaling relation and a considerably better catalyst.These industrial advancements can be contrasted to the naturally occurring systems as enzymes including nitrogenase. Despite that this biological system is known to be able to make ammonia at ambient temperatures and pressure, it is a very inefficient process. Hence, not only do we need to find inorganic catalyst but they have to be scalable andmore efficient than the naturally occurring process. The challenge remains to develop a systematic approach to understanding effects like this in order to give us a toolbox of strategies to design radically better catalysts. ACKNOWLEDGEMENT

    Layered-double hydroxides and derived oxide as CRM-free highly active catalysts for the reduction of 4-nitrophenol

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    The present study investigates the possibility to abate 4-nitrophenol (4NP), a well-known persistent contaminant in wastewaters, using Layered-Double Hydroxides (LDH) based catalysts, non-noble metals-based and Critical Raw Materials-free materials used for 4NP reduction with NaBH4. It is reported the study of the effects of several parameters on the overall reaction kinetic by in situ monitoring of the 4NP reduction through UV-Vis Spec-troscopy, as: (i) LDH's trivalent and divalent cation nature, (ii) LDH thermal treatment, (iii) substrate/catalyst ratio, and (iv) stirring rate. The reasons that led to increased activity were identified and correlated with cat-alyst's structure characterization. The results pointed out that LDH enhance synergic effect of nickel and copper by increasing reducibility which is further raised when defective mixed oxide by calcination is obtained. This resulted in enhanced 4NP reduction which could be further increased by calcination providing a highly reducible mixed oxide

    Investigations of Carbon Nitride-Supported Mn3O4 Oxide Nanoparticles for ORR

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    Earth-abundant Mn-based oxide nanoparticles are supported on carbon nitride using two different immobilization methods and tested for the oxygen reduction reaction. Compared to the metal free CN, the immobilization of Mn oxide enhances not only the electrocatalytic activity but also the selectivity towards the 4e- reduction reaction of O-2 to H2O. The XPS analysis reveals the interaction of the pyridine N species with Mn3O4 nanoparticles being particularly beneficial. This interaction is realized-although to a limited extent-when preparing the catalysts via impregnation; via the oleic acid route it is not observed. Whilst this work shows the potential of these systems to catalyze the ORR, the main limiting factor is still the poor conductivity of the support which leads to overpotential

    X-ray computed microtomography: A non-invasive and time-efficient method for identifying and screening Roman copper-based coins

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    This study utilises X-ray Computed Micro-Tomography (ÎĽXCT) as a non-destructive and non-invasive method to recover the original surface features and reveal the characteristics of encrusted, illegible Roman copper-based coins before any physical cleaning process is performed. The coins were retrieved from the topsoil during an archaeological survey in the countryside of the ancient city of Aquileia, Italy, and were severely degraded, covered with accumulated matter and pronounced encrustations developed over centuries of aging buried in soil. Despite their condition, most of the coins were identified from a numismatic standpoint using tomographic data alone, with the aid of reference images. They were subsequently cleaned using traditional manual methods and the results compared with ÎĽXCT. X-ray Fluorescence (XRF) analysis of the coins after the physical cleaning confirmed their numismatic attribution and revealed information regarding the influence of different alloy compositions on the applicability of the ÎĽXCT method, as well as on the corrosion process of the coins. This study showcases how the application of ÎĽXCT on fragile corroded metal artifacts prior to any intrusive manual procedures can expedite the identification process, mitigating the risk of information loss caused by physical handling and cleaning. This approach proves particularly valuable when dealing with large numbers of coins that would typically require restoration for identification purposes. It also emphasises the numerous advantages of using ÎĽXCT for coin identification, provenance determination, dating, virtual restoration, digitisation, and long-term preservation

    Heart failure with preserved systolic function: prevalence and clinical features in a cohort of patients admitted to internal medicine units. The study PRESYF-HF Tuscany.

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    Background. There is uncertainty about the prevalence and clinical characteristics of heart failure (HF) patients with preserved systolic function (PRESYF). Aim. To analyze the prevalence and clinical characteristics of patients with PRESYF in an unselected cohort of subjects consecutively hospitalized for HF. Methods. The study cohort included 338 patients consecutively admitted for HF at 24 Internal Medicine units homogeneously settled in Tuscany area (Italy). We did not have any criteria for exclusion. All patients had an echocardiographic measure of left ventricular ejection fraction (LVEF) within 72 hours from hospital admission. Patients with LVEF > 50% were considered to have PRESYF. Results. The patients with PRESYF were 112 (33,1%), those with depressed systolic function (DESYF) 226 (66,9%). In the group PRESYF were prevalent female sex, hypertensive etiology, and elevated BMI. The distribution for classes of age shows a great frequency of PRESYF in the elderly. Conclusion. About one third of patients admitted for HF have a PRESYF. They are different compared to those with DESYF. A correct identification of this form of HF may be important in clinical practice for more targeted therapeutic options and for prognostic implications

    Preclinical Evidence of Progesterone as a New Pharmacological Strategy in Human Adrenocortical Carcinoma Cell Lines

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    BACKGROUND Adrenocortical cancer (ACC) is a rare malignancy with a dismal prognosis. The treatment includes mitotane and EDP chemotherapy (etoposide, doxorubicin, and cisplatin). However, new therapeutic approaches for advanced ACC are needed, particularly targeting the metastatic process. Here, we deepen the role of progesterone as a new potential drug for ACC, in line with its antitumoral effect in other cancers. METHODS NCI-H295R, MUC-1, and TVBF-7 cell lines were used and xenografted in zebrafish embryos. Migration and invasion were studied using transwell assays, and MMP2 activity was studied using zymography. Apoptosis and cell cycle were analyzed by flow cytometry. RESULTS Progesterone significantly reduced xenograft tumor area and metastases formation in embryos injected with metastatic lines, MUC-1 and TVBF-7. These results were confirmed in vitro, where the reduction of invasion was mediated, at least in part, by the decrease in MMP2 levels. Progesterone exerted a long-lasting effect in metastatic cells. Progesterone caused apoptosis in NCI-H295R and MUC-1, inducing changes in the cell-cycle distribution, while autophagy was predominantly activated in TVBF-7 cells. CONCLUSION Our results give support to the role of progesterone in ACC. The involvement of its analog (megestrol acetate) in reducing ACC progression in ACC patients undergoing EDP-M therapy is now under investigation in the PESETA phase II clinical study

    Cytotoxic Effect of Progesterone, Tamoxifen and Their Combination in Experimental Cell Models of Human Adrenocortical Cancer

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    Progesterone (Pg) and estrogen (E) receptors (PgRs and ERs) are expressed in normal and neoplastic adrenal cortex, but their role is not fully understood. In literature, Pg demonstrated cytotoxic activity on AdrenoCortical Carcinoma (ACC) cells, while tamoxifen is cytotoxic in NCI-H295R cells. Here, we demonstrated that in ACC cell models, ERs were expressed in NCI-H295R cells with a prevalence of ER-β over the ER-α.Metastasis-derived MUC-1 and ACC115m cells displayed a very weak ER-α/β signal, while PgR cells were expressed, although at low level. Accordingly, these latter were resistant to the SERM tamoxifen and scarcely sensitive to Pg, as we observed a lower potency compared to NCI-H295R cells in cytotoxicity (IC50: MUC-1 cells: 67.58 µM (95%CI: 63.22-73.04), ACC115m cells: 51.76 µM (95%CI: 46.45-57.67) and cell proliferation rate. Exposure of NCI-H295R cells to tamoxifen induced cytotoxicity (IC50: 5.43 µM (95%CI: 5.18-5.69 µM) mainly involving ER-β, as their nuclear localization increased after tamoxifen: Δ A.U. treated vs untreated: 12 h: +27.04% (p < 0.01); 24 h: +36.46% (p < 0.0001). This effect involved the SF-1 protein reduction: Pg: -36.34 ± 9.26%; tamoxifen: -46.25 ± 15.68% (p < 0.01). Finally, in a cohort of 36 ACC samples, immunohistochemistry showed undetectable/low level of ERs, while PgR demonstrated a higher expression. In conclusion, ACC experimental cell models expressed PgR and low levels of ER in line with data obtained in patient tissues, thus limiting the possibility of a clinical approach targeting ER. Interestingly, Pg exerted cytotoxicity also in metastatic ACC cells, although with low potency. Keywords: ACC cell lines; ACC primary cells; adrenocortical carcinoma; estrogen receptors; progesterone receptors; tamoxifen
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