Search results for "Oxide"
showing 10 items of 6424 documents
The antioxidant behavior of functional nitroxide grafted polyethylene samples
2015
In this work, the thermo- and photo-oxidation stability of functional nitroxide grafted polyethylene (PE) samples was tested.
Effects of phenolic-like intercalated layered double hydroxides on poly(lactic acid) based nanocomposites
2015
Two phenolic-like antioxidants (AOs), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 6-hydroxy-2,5,7,8-tetrametilcromano-2-carboxylate anions, were intercalated by anion exchange in layered double hydroxides (LDHs). The two AO-LDHs were dispersed by ultrasound-assisted solution mixing in poly(lactic acid) (PLA) and the thermal oxidation stability of the composites was evaluated following the variation of the molecular weight by SEC, after a controlled aging process, and determining the oxidation induction time (OIT) by DSC. The results evidenced that the intercalation of both the AO molecules within the LDH galleries prevent their own thermal and thermo-oxidative degradation as well a…
Chamazulene-Rich Artemisia arborescens Essential Oils Affect the Cell Growth of Human Melanoma Cells
2020
Artemisia arborescens is an aromatic shrub whose essential oils are considered a potential source of molecules with industrial and pharmaceutical interest. The chemical profile of A. arborescens essential oils (EOs) was shown to be quite variable and various chemotypes have been identified. In this study, we compared the EOs composition of A. arborescens leaves and flowers collected from four different locations in Sicily. The EOs were assayed for their antiproliferative activity against A375 human malignant melanoma cells, also testing cell viability and cell membrane integrity. The evaluation of DNA fragmentation and caspase-3 activity assay was employed for the detection of apoptosis. Th…
Bronchial hyperresponsiveness (BHR) or exhaled nitric oxide concentration (eNO) do not predict exercise-induced bronchoconstriction (EIB) in atopic c…
2005
An Atom-Economical Approach to Functionalized Single-Walled Carbon Nanotubes: Reaction with Disulfides
2013
Owing to their unique structure, thermal stability, and mechanical and electronic properties, single-walled carbon nanotubes (SWCNTs) have been a subject of continuous and intense interest. However, various applications in many fields, such as molecular electronics, solar cells, and nanomedicine, often require the development of reproducible protocols for the chemical modification of SWCNTs. In fact, one of the main drawbacks of the use of SWCNTs is their tendency to aggregate and intrinsic poor solubility, which prevent their manipulation and limit their potential. To date, several methods have been described for the chemical functionalization of SWCNTs; however, new versatile and reliable…
Theoretical characterization of the photochemical reaction CO2+O(3P)→CO+O2 related to experiments in solid krypton
2020
Formation and decomposition of the complex of carbon dioxide and atomic oxygen are characterized by quantum chemistry methods aiming to rationalize experimental studies in solid krypton. The observed FTIR spectra reflected the temporal evolution of the system after irradiation showing the bands of reactants, intermediates and products. Advanced quantum chemistry calculations show that the T-shape complex CO2…O(3P) can be formed in the matrix. Its excitation by the 193 nm light results in the charge-transfer state CO2+…O-, which evolves to the reaction intermediate CO3. The latter species decomposes to CO + O2 following pathways on the excited state energy surfaces. peerReviewed
5-Azacytidine Inhibits the Activation of Senescence Program and Promotes Cytotoxic Autophagy during Trdmt1-Mediated Oxidative Stress Response in Insu…
2022
5-Azacytidine (5-azaC), a methyltransferase inhibitor and anticancer drug, can promote several cellular stress responses such as apoptosis, autophagy, and senescence. The action of 5-azaC is complex and can be modulated by dose, time of treatment, and co-administration with oxidants. Insulinoma is a rare pancreatic neuroendocrine tumor with limited chemotherapeutic options. In the present study, two cellular models of insulinoma were considered, namely NIT-1 and β-TC-6 mouse cells, to evaluate the effects of 5-azaC post-treatment during hydrogen peroxide-induced oxidative stress. 5-azaC attenuated the development of oxidant-induced senescent phenotype in both cell lines. No pro-apoptotic ac…
Analysis of particles size distributions in Mg(OH)2 precipitation from highly concentrated MgCl2 solutions
2022
Magnesium is a raw material of great importance, which attracted increasing interest in the last years. A promising route is to recover magnesium in the form of Magnesium Hydroxide via precipitation from highly concentrated Mg2+ resources, e.g. industrial or natural brines and bitterns. Several production methods and characterization procedures have been presented in the literature reporting a broad variety of Mg(OH)2 particle sizes. In the present work, a detailed experimental investigation is aiming to shed light on the characteristics of produced Mg(OH)2 particles and their dependence upon the reacting conditions. To this purpose, two T-shaped mixers were employed to tune and control the…
A globally relevant stock of soil nitrogen in the Yedoma permafrost domain
2022
AbstractNitrogen regulates multiple aspects of the permafrost climate feedback, including plant growth, organic matter decomposition, and the production of the potent greenhouse gas nitrous oxide. Despite its importance, current estimates of permafrost nitrogen are highly uncertain. Here, we compiled a dataset of >2000 samples to quantify nitrogen stocks in the Yedoma domain, a region with organic-rich permafrost that contains ~25% of all permafrost carbon. We estimate that the Yedoma domain contains 41.2 gigatons of nitrogen down to ~20 metre for the deepest unit, which increases the previous estimate for the entire permafrost zone by ~46%. Approximately 90% of this nitrogen (37 gigaton…
Homo- and Heterobinuclear Cu2+ and Zn2+ Complexes of Ditopic Aza Scorpiand Ligands as Superoxide Dismutase Mimics
2017
Two polytopic aza-scorpiand-like ligands, 6-[7-(diaminoethyl)-3,7-diazaheptyl]-3,6,9-triaza-1-(2,6-pyridina)cyclodecaphane (L1) and 6-[6′-[3,6,9-triaza-1-(2,6-pyridina)cyclodecaphan-6-yl]-3-azahexyl]-3,6,9-triaza-1-(2,6-pyridina)cyclodecaphane (L2), have been synthesized. The acid–base behavior and Cu2+, Zn2+, and Cu2+/Zn2+ mixed coordination have been analyzed by potentiometry, cyclic voltammetry, and UV–vis spectroscopy. The resolution of the crystal structures of [Cu2L2Cl2](ClO4)2·1.67H2O (1), [Cu2HL2Br2](ClO4)3·1.5H2O (2), and [CuZnL2Cl2](ClO4)2·1.64H2O (3) shows, in agreement with the solution data, the formation of homobinuclear Cu2+/Cu2+ and heterobinuclear Cu2+/Zn2+ complexes. The m…