Influence of Intermittent Heating during Maceration on the Antioxidant Capacity of Some Grape Seeds and Skins

Ethanolic extracts from seeds and skins of three red grape varieties, namely, 'Cabernet Sauvignon', 'Merlot' and 'Burgund' from a Romanian winery, were prepared by maceration using different temperature conditions. The stable free radicals DPPH (2, 2-diphenyl- 1-picrylhydrazyl) and Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidin-N-oxyl) were used in order to evaluate the antioxidant capacity of the extracts. The variation in time of free radical concentration was followed by double integration of the EPR spectra of the samples obtained after maceration under different conditions (room temperature and intermittent heating). Results showed that the antioxidant capacity depends on the nature of analysed samples (either being seeds or skins) and grape variety. The results also show that the intermittent heating during maceration leads to a decrease of the antioxidant capacity of samples

"Yellow" laccase from Sclerotinia sclerotiorum is a blue laccase that enhances its substrate affinity by forming a reversible tyrosyl-product adduct.

Yellow laccases lack the typical blue type 1 Cu absorption band around 600 nm; however, multi-copper oxidases with laccase properties have been reported. We provide the first evidence that the yellow laccase isolated from Sclerotinia sclerotiorum is obtained from a blue form by covalent, but nevertheless reversible modification with a phenolic product. After separating the phenolics from the extracellular medium, a typical blue laccase is obtained. With ABTS as model substrate for this blue enzyme, a non-natural purple adduct is formed with a spectrum nearly identical to that of the 1:1 adduct of an ABTS radical and Tyr. This modification significantly increases the stability and substrate affinity of the enzyme, not by acting primarily as bound mediator, but by structural changes that also alters the type 1 Cu site. The HPLC-MS analyses of the ABTS adduct trypsin digests revealed a distinct tyrosine within a unique loop as site involved in the modification of the blue laccase form. Thus, S. sclerotiorum yellow laccase seems to be an intrinsically blue multi-copper oxidase that boosts its activity and stability with a radical-forming aromatic substrate. This particular case could, at least in part, explain the enigma of the yellow laccases

‘Super-reduced’ iron under physiologically-relevant conditions

EPR spectroscopy is employed to demonstrate chemical production of formally Fe(i) and Fe(0) states of phthalocyanines in water at room temperature, and physiologically-relevant pH. © The Royal Society of Chemistry 2010

In Vitro Studies Demonstrate Antitumor Activity of Vanadium Ions from a CaO-P₂O₅-CaF₂:V₂O₅ Glass System in Human Cancer Cell Lines A375, A2780, and Caco-2

In this research, we investigated the structural and biological properties of phosphate glasses (PGs) after the addition of V2O5. A xV2O5∙(100 − x)[CaF2∙3P2O5∙CaO] glass system with 0 ≤ x ≤ 16 mol% was synthesized via a conventional melt-quenching technique. Several analysis techniques (dissolution tests, pH, SEM-EDS, FT-IR, and EPR) were used to obtain new experimental data regarding the structural behavior of the system. In vitro tests were conducted to assess the antitumor character of V2O5-doped glass (x = 16 mol%) compared to the matrix (x = 0 mol%) and control (CTRL-) using several tumoral cell lines (A375, A2780, and Caco-2). The characterization of PGs showed an overall dissolution rate of over 90% for all vitreous samples (M and V1–V7) and the high reactivity of this system. EPR revealed a well-resolved hyperfine structure (hfs) typical of vanadyl ions in a C4v symmetry. FT-IR spectra showed the presence of all structural units expected for P2O5, as well as very clear depolymerization of the vitreous network induced by V2O5. The MTT assay indicated that the viability of tumor cells treated with V7-glass extract was reduced to 50% when the highest concentration was used (10 µg/mL) compared to the matrix treatment (which showed no cytotoxic effect at any concentration). Moreover, the matrix treatment (without V2O5) provided an optimal environment for tumor cell attachment and proliferation. In conclusion, the two types of treatment investigated herein were proven to be very different from a statistical point of view (p < 0.01), and the in vitro studies clearly underline the cytotoxic potential of vanadium ions from phosphate glass (V7) as an antitumor agent

Aspects Regarding of a UGV Fire Fighting Thermal Shield

This article presents aspects related to the protection (with a double shield made of stainless steel) of a robot for emergency situations against the effect of flames due to a fire. The ground robot is semi-autonomous/autonomous, with a wheeled propeller (6 × 6). The robot, designed and built at the TRL 2 level, is intended for fire investigation, monitoring, and intervention (and, in particular, for petrochemical plants). The role of the shield is to protect the equipment that is part of the robot including its controllers, sensors, communications, power supply, etc. The need to mount a thermal protection shield on the intervention robot was given by the fact that fires at petrochemical plants generate very large thermal fields and gradients which are responsible for creating blind spots. These blind spots do not allow intervention crews to see what is happening in that area. These blind spots are characterized by very high temperatures. The dynamics of these fires can be unpredictable. Therefore, to analyze the performance of the heat shield in this study we perform a numerical-experimental analysis

Synthesis and Structural Characterization of CaO-P2O5-CaF:CuO Glasses with Antitumoral Effect on Skin Cancer Cells

Copper is one of the most used therapeutic metallic elements in biomedicine, ranging from antibacterial approaches to developing new complexes in cancer therapy. In the present investigation, we developed a novel xCuO&#8729;(100 &minus; x) [CaF2&#8729;3P2O5&#8729;CaO] glass system with 0 &le; x &le; 16 mol% in order to determine the influence of doping on the composition structure of glasses. The samples were characterized by dissolution tests, pH measurements, Fourier-transform infrared spectroscopy (FT-IR), electron paramagnetic resonance (EPR), Scanning Electron Microscopy with energy dispersive spectroscopy (SEM-EDX) and afterward, their antitumor character was assessed. The glasses were mostly soluble in the aqueous medium, their dissolution rate being directly proportional to the increase in pH and the level of doping up to x = 8 mol%. FT-IR spectra of glass samples show the presence of all structural units characteristic to P2O5 in different rates and directly depending on the depolymerization process. SEM-EDX results revealed the presence of an amorphous glass structure composed of P, O, Ca, and Cu elements. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay showed strong cytotoxicity for tumoral cells A375 even in low concentrations for Cu-treatment. In contrast, the copper-free matrix (without Cu) determined a proliferative effect of over 70% viability for all concentrations used

Ascorbate peroxidase activity of cytochrome<i>c</i>

The peroxidase-type reactivity of cytochrome c is proposed to play a role in free radical production and/or apoptosis. This study describes cytochrome c catalysis of peroxide consumption by ascorbate. Under conditions where the sixth coordination position at the cytochrome c heme iron becomes more accessible for exogenous ligands (by carboxymethylation, cardiolipin addition or by partial denaturation with guanidinium hydrochloride) this peroxidase activity is enhanced. A reaction intermediate is detected by stopped-flow UV-vis spectroscopy upon reaction of guanidine-treated cytochrome c with peroxide, which resembles the spectrum of globin Compound II species and is thus proposed to be a ferryl species. The ability of physiological levels of ascorbate (10μM) to interact with this species may have implications for mechanisms of cell signalling or damage that are based on cytochrome c/peroxide interactions. © 2011 Informa UK, Ltd

Polyphenolic Composition, Antioxidant and Antibacterial Activities for Two Romanian Subspecies of Achillea distans Waldst. et Kit. ex Willd.

The aim of this work was to study the chemical composition, antioxidant and antibacterial properties of Achillea distans Waldst. et Kit. subsp. distans and Achillea distans Waldst. et Kit. subsp. alpina Rochel, from the Rodna Mountains (Romania). The identification and quantification of major phenolic compounds was performed by a HPLC-MS method. The total polyphenolic and flavonoid content was determined spectrophotometrically. The antioxidant activity was evaluated using the DPPH bleaching method, trolox equivalent antioxidant capacity assay (TEAC), hemoglobin ascorbate peroxidase activity inhibition (HAPX) assay, and an Electron Paramagnetic Resonance (EPR) spectroscopy method. A data indicated that A. distans subsp. alpina extract has more antioxidant activity than A. distans subsp. distans extract. Luteolin, apigenin, quercetin, caffeic and chlorogenic acids were present in the two extracts of A. distans, but in different amounts. Three flavonoids were detected only in A. distans subsp. alpina. The polyphenol-richer A. distans subsp. alpina extract showed a higher antioxidant activity than A. distans subsp. distans extract. A. distans subsp. distans extract showed inhibitory activity for Gram-positive bacteria, as evaluated with four species. The quantitative and qualitative differences between the two subspecies of Achillea distans could be used as a potential taxonomic marker in order to distinguish the species

Influence of the Stiffness of the Robotic Arm on the Position of the Effector of an EOD Robot

Terrestrial robots are being employed in a variety of sectors and for a variety of objectives. The purpose of this paper is to analyze and validate an analytical–numerical model of a robotic arm’s behavior. The proposed robot was designed to replace human personnel who remove ammunition or explosive devices. At the same time, the influence of the stiffness of the EOD robotic arm on the position of the effector in a variety of geometric task configurations was investigated. In order to obtain results relevant to the investigation, the angles of rotation under the load of each component of the arm’s composition and the vertical movement of the effector were measured. The main conclusions emphasize that a lower stiffness comes from the components of linear motors, which act on the elements of the robotic arm, and they substantially influence the elastic behavior of the arm. In addition, the constructive components of the arm have high rigidity compared to those of the linear actuators

Influence of the Stiffness of the Robotic Arm on the Position of the Effector of an EOD Robot

Terrestrial robots are being employed in a variety of sectors and for a variety of objectives. The purpose of this paper is to analyze and validate an analytical&ndash;numerical model of a robotic arm&rsquo;s behavior. The proposed robot was designed to replace human personnel who remove ammunition or explosive devices. At the same time, the influence of the stiffness of the EOD robotic arm on the position of the effector in a variety of geometric task configurations was investigated. In order to obtain results relevant to the investigation, the angles of rotation under the load of each component of the arm&rsquo;s composition and the vertical movement of the effector were measured. The main conclusions emphasize that a lower stiffness comes from the components of linear motors, which act on the elements of the robotic arm, and they substantially influence the elastic behavior of the arm. In addition, the constructive components of the arm have high rigidity compared to those of the linear actuators