18 research outputs found

    Sustainable protocol for the reduction of nitroarenes by heterogeneous Au@SBA‐15 using NaBH4 under flow conditions

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    Gold‐incorporated SBA‐15 catalyst was prepared by a solvent‐free ball milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH using NaBH4 as reducing agent. The catalyst was reused in batch conditions over 5 consecutive runs without detecting any losses of activity and selectivity. Considering the high chemical stability and reusability of the catalytic system, a continuous flow protocol was also investigated and defined in order to minimize the production of waste associated to the process and optimize the continuous reuse of the catalyst. Benefits of flow conditions were proven by TON values that increased from 47.5 to 1902 and also by the minimization of both leaching (9.5 vs 1 ppm) and E‐factor values (8 vs 23 in batch)

    A Comparative Study on Opto-Thermal Properties of Natural Clay Bricks Incorporating Dredged Sediments

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    The brick industry is currently facing a shortage of natural resources. Despite this, the demand for construction bricks is progressively increasing. Alternative materials, such as dredged sediments and solid organic waste, have been recently proposed as options to replace natural clay in brick manufacturing. Potential exploitation of dredged sediments in clay bricks is evaluated in this study. The chemical composition of the mixtures and the opto-thermal properties of brick samples, which differed for the dredged sediment content (from 10% to 50% of the clay weight), were investigated. Chemical analyses detected lower concentrations of heavy metals in bricks incorporating dredged sediments (DS). Negligible variations in thermal conductivity, thermal diffusivity, and specific heat were observed by increasing the amount of DS in the mixture. In particular, the thermal conductivity values ranged between 0.45 ± 0.03 W m−1 K−1 (DS-50) and 0.50 ± 0.03 W m−1 K−1 (DS-30). Conversely, the color shift value and spectral reflectance in the infrared field were found directly proportional to the concentration of DS. Using dredged sediments as building material demonstrated to be a solution to the problem of their disposal and the scarcity of raw materials, reducing the global warming score by up to 2.8%

    EphrinA1 activates a Src/focal adhesion kinase-mediated motility response leading to rho-dependent actino/myosin contractility.

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    Eph receptors and ephrin ligands are widely expressed in epithelial cells and mediate cell repulsive motility through heterotypic cell-cell interactions. Several Ephs, including EphA2, are greatly overexpressed in certain tumors, in correlation with poor prognosis and high vascularity in cancer tissues. The ability of several Eph receptors to regulate cell migration and invasion likely contribute to tumor progression and metastasis. We report here that in prostatic carcinoma cells ephrinA1 elicits a repulsive response that is executed through a Rho-dependent actino/myosin contractility activation, ultimately leading to retraction of the cell body. This appears to occur through assembly of an EphA2-associated complex involving the two kinases Src and focal adhesion kinase (FAK). EphrinA1-mediated repulsion leads to the selective phosphorylation of Tyr-576/577 of FAK, enhancing FAK kinase activity. The repulsive response elicited by ephrinA1 in prostatic carcinoma cells is mainly driven by a Rho-mediated phosphorylation of myosin light chain II, in which Src and FAK activation are required steps. Consequently, Src and FAK are upstream regulators of the overall response induced by ephrinA1/EphA2, instructing cells to retract the cell body and to move away, probably facilitating dissemination and tissue invasion of ephrin-sensitive carcinomas

    Immobilized Palladium Nanoparticles on Zirconium Carboxy-Aminophosphonates Nanosheets as an Efficient Recoverable Heterogeneous Catalyst for Suzuki–Miyaura and Heck Coupling

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    Zirconium phosphate glycine diphosphonate nanosheets (ZPGly) have been used as support for the preparation of solid palladium nanoparticles, namely Pd@ZPGly. Thanks to the presence of carboxy-aminophosponate groups on the layer surface, ZPGly-based materials were able to stabilize a high amount of palladium (up to 22 wt %) also minimizing the amount of metal leached in the final products of representative important cross-coupling processes selected for proving the catalysts’ efficiency. The catalytic systems have been fully characterized and used in low amounts (0.1 mol %) in the Suzuki–Miyaura and Heck cross-couplings. Moreover, the protocols were optimized for the use of recoverable azeotropic mixtures (aq. EtOH 96% or aq. CH3CN 84%, respectively) and in the flow procedure allowing one to isolate the final pure products, without any purification step, with very low residual palladium content and with a very low waste production

    Redox-based escape mechanism from death: the cancer lesson.

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    We review here current evidence on the role of reactive oxygen species (ROS) and of the intracellular redox state in governing crucial steps of the metastatic process, from cell detachment from the primary tumor to final colonization of the distant site. In particular, we discuss the redox-dependent aspects of cell glycolytic metabolism (Warburg effect), of cell juggling between different motility styles (epithelial-to-mesenchymal and mesenchymal-to-amoeboid transition), of cell resistance to anoikis and of cell interaction with the stromal components of the metastatic niche. Central to this overview is the concept that metastasis can be viewed as an integrated "escape program" triggered by redox changes and instrumental at avoiding oxidative stress within the primary tumor. In this novel perspective, metabolic, motility, and prosurvival choices of the cell along the entire metastatic process can be interpreted as exploiting redox-signaling cascades to monitor oxidative/reductive environmental cues and escape oxidative damage. We also propose that this theoretic framework be applied to "normal" evasion/invasion programs such as in inflammation and development. Furthermore, we suggest that the intimate connection between metastasis, inflammation, and stem cells results, at least in part, by the sharing of a common redox-dependent strategy for infiltration, survival, dissemination, and patterning

    High Solid and Low Cellulase Enzymatic Hydrolysis of Cardoon Stems Pretreated by Acidified γ-Valerolactone/Water Solution

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    Lignocellulosic biomass is a nonedible matrix that can be efficiently exploited as feedstock in an integrated biorefinery after a proper pretreatment. An organosolv pretreatment using an acidified γ-valerolactone (GVL)/water solution was proposed to improve the cellulose enrichment and enzymatic saccharification of cardoon (Cynara cardunculus L.) stems. At the optimal pretreatment condition (140 °C, 0.6 GVL/water, and 2.24% H2SO4), xylan was efficiently removed from the cardoon, and up to 50% of its content was recovered in the aqueous fraction, while 86% of the cellulose was retained in the solid fraction. The resulting cardoon pulp showed a cellulose content of 91.5% and an enzymatic digestibility of 100%. An overall glucose production of 37.17 g/100 g raw material (90% theoretical maximum) was obtained using high solid loading (20% w/w) and a high enzyme dosage (60 FPU/g cellulose). At a low enzyme dosage, glucose concentrations of 169 g/L and 210 g/L were achieved using 10 FPU/g cellulose and 20 FPU/g cellulose, respectively. Therefore, an organosolv pretreatment can be an effective process for producing cellulose-enriched pulp with enhanced enzymatic digestibility from cardoon stems, providing a promising option for green lignocellulosic biorefineries that aim to produce high concentrations of glucose with low cellulase addition

    Negative DAT-SPECT in Old Onset Parkinson's Disease: An Additional Pitfall?

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    Background Scans without evidence of dopaminergic deficit (SWEDDs) refer to patients clinically diagnosed with Parkinson's disease (PD), but showing normal findings on dopamine transporter single-photon emission computed tomography (DAT-SPECT). This entity remains highly debated, but recent findings suggesting that DAT-SPECT does not reflect either nigral cell bodies or striatal fibers of dopaminergic nigrostriatal neurons could improve our understanding of SWEDDs. Notably, compensatory downregulation of DAT in the early stages of PD seems to be less efficient in older-onset than in young-onset patients. Cases We report eight patients with old-onset clinical parkinsonism and a positive response to levodopa in which DAT-SPECT was normal both visually and semiquantitatively. Two subjects demonstrated an abnormal scan when repeated later. Conclusions We suggest that old-onset patients may truly have dopaminergic degeneration despite normal imaging results, presumably because they are diagnosed in the early stages confirming less efficient striatal compensatory strategies in old-age onset PD
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