Electromagnetic dispersion modeling and measurements for HVDC power cables

This paper provides a general framework for electromagnetic modeling, computation and measurements regarding the wave propagation characteristics of High-Voltage Direct Current (HVDC) power cables. The modeling is focused on very long (10 km or more) HVDC power cables and the relevant frequency range is therefore in the low-frequency regime of about 0-100 kHz. An exact dispersion relation is formulated together with a discussion on practical aspects regarding the computation of the propagation constant and the related characteristic impedance. Experimental time-domain measurement data from an 80 km long HVDC power cable is used to validate the model. It is concluded that a single-mode transmission line model is not adequate to account for the mismatch between the power cable and the instrumentation. A mismatch calibration procedure is therefore devised to account for the connection between the measurement equipment and the cable. A dispersion model is thus obtained that is accurate for early times of pulse arrival. To highlight the potential of accurate electromagnetic modeling, an example of high-resolution length-estimation is discussed and analyzed using statistical methods based on the Cramer-Rao lower bound. The analysis reveals that the estimation accuracy based on the present model (and its related model error) is in the order of 100 m for an 80 km long power cable, and that the potential accuracy using a perfect model based on the given measurement data is in the order of centimeters

Comparison of Bond Strength of Monolithic CAD-CAM Materials to Resin Cement Using Different Surface Treatment Methods

Objective: To compare the bond strength of monolithic CAD-CAM materials to resin cement using different surface treatment methods. Materials and Methods: Lithium disilicate glass ceramic (IPS e-max CAD), zirconia-reinforced lithium silicate ceramic (Vita Suprinity), resin nanoceramic (Lava Ultimate), and hybrid ceramic (Vita Enamic) were used. Five groups of CAD-CAM blocks were treated as follows: control (C), HF etching (HF), HF etching + silanization (HF + S), sandblasting (SB), and sandblasting + silanization (SB + S). After surface treatments, SEM analyses were conducted. Specimens were cemented with self-adhesive resin cement (Theracem) and stored in distilled water at 37 degrees C for 24 h. Shear bond strength (SBS) was measured, and failure types were categorized. Results were analyzed using two-way ANOVA and the post-hoc Tukey test. Results: Statistical analysis revealed significant differences between SBS values obtained for different surface treatments and CAD-CAM block types (P < .001). Among the CAD-CAM materials, the highest SBS was reported in the HF + S group for Vita Enamic. Although IPS e.max CAD, Vita Suprinity, and Vita Enamic showed higher bond strength when treated with HF + S, Lava Ultimate has the highest bond strength value when treated with SB + S. Conclusions: The bond strength of CAD-CAM materials was influenced by surface treatment. Additionally, silanization significantly improved the bond strength of all materials except Lava Ultimate

Effects of vitamin C or vitamin E supplementation on Cadmium induced oxidative stress and anaemia in broilers

The aim of this study was to investigate the possible protective effects of vitamins C and E on lipid peroxidation (LPO), antioxidant systems and erythrocyte parameters in broilers chronically exposed to cadmium (Cd). One day old Ross broiler chickens were assigned to 4 equal groups (n = 12) according to the diet regimen; in the control group, birds received basal standard starter and grower diets, in Cd group they were supplemented with Cd (60 mg/kg) and in the 2 other groups, they were supplemented with Cd and with vitamin C (400 mg/kg) or with vitamin E (250 mg/kg) during the 42 clays long experimental period. The Cd exposition induced an oxidative stress characterised by the significant increase in plasma MDA concentrations coupled to significant decreases in enzyme antioxidant SOD (superoxide dismutase), CAT (catalase) and GSH-Px (glutathione peroxidase) activities and in plasma vitamin E, beta-carotene and uric acid concentrations. A moderate regenerative anaemia (low haemoglobinemia, erythrocyte name-ration and haematocrit associated with increase of the mean corpuscular volume) was also observed in the Cd group. Treatments with the vitamins C or E significantly reduced the lipid peroxidation but the antioxidant enzyme CAT and GSH-Px activities and vitamin E concentrations were significantly improved only with the vitamin E supplementation. Furthermore, the both types of vitamin supplementation, but particularly with ascorbate, have significantly increased the haemoglobinemia and the erythrocyte counts. These results clearly showed that vitamins C and E alleviate the oxidative effects of Cd at least partially and that the vitamin E exhibits more powerful antioxidant effects whereas vitamin C corrects more efficiently the anaemia

Recurrent Bilateral Breast Abscesses after Sternotomy

Median sternotomy is the most commonly used incision in cardiothoracic procedures. Development of breast abscess after sternotomy is a very rare situation. We present a case of sternal wound infection with recurrent bilateral breast abscess after sternotomy. Our case is the first and only case in the literature due to the presence of sternal wound infection with recurrent bilateral breast abscess after sternotomy

Cytotoxicity of some edible mushrooms extracts over liver hepatocellular carcinoma cells in conjunction with their antioxidant and antibacterial properties

Background: Mushrooms have been valued for their nutritive content and as traditional medicines; several important medicinal properties of mushrooms have been recognized worldwide. Objective: The purpose of this study was to elucidate the cell growth inhibitory potential of four edible mushrooms; Coprinus comatus (O.F. Mull.) Pers. (Agaricaceae), Tricholoma fracticum (Britzelm.) Kreisel (Tricholomataceae), Rhizopogon luteolus Fr. and Nordholm (Rhizopogonaceae), Lentinus tigrinus (Bull.) Fr. (Polyporaceae) on hepatocellular carcinoma (HepG2) cells in conjunction with their antioxidant and antibacterial capacities. Materials and Methods: Five different extracts of edible mushrooms were obtained using water, methanol, acetone, n-hexane and chloroform as solvent systems for cytotoxic, antioxidant and antibacterial properties. Results: C. comatus showed substantial in vitro cytotoxic activity against HepG2 cell lines with all extracts especially with chloroform 50% inhibition (IC50 value of 0.086 mg/ml) and acetone (IC50 value of 0.420 mg/ml). Chloroform extract of C. comatus had maximum amount of beta-carotene (25.94 mu g/mg), total phenolic content (76.32 mu g/mg) and lycopene (12.00 mu g/mg), and n-hexane extract of L. tigrinus had maximum amount of flavonoid (3.67 mu g/mg). While chloroform extract of C. comatus showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) capturing activity (1.579 mg/ml), the best result for metal chelating activity was obtained from methanolic extract (0.842 mg/ml). Moreover, all tested mushrooms demonstrated antibacterial activity and n-hexane extract of L. tigrinus and acetone extracts of T. fracticum were the most active against tested microorganism. Conclusion: These results indicate that different extracts of investigated mushroom have considerable cytotoxic, antioxidant and antibacterial properties and may be utilized as a promising source of therapeutics

The characterization of phenolic compounds via LC-ESI-MS/MS, antioxidant, enzyme inhibitory activities of Salvia absconditiflora, Salvia sclarea, and Salvia palaestina: A comparative analysis

Abstract Salvia L. genus, one of the medicinal and aromatic plants belonging to the Lamiaceae family, is represented by many endemic species in temperate regions worldwide. The Salvia species have plenty of usages in traditional medicine, important pharmacological effects and economic value. In this context, this study was conducted to evaluate the chemical profile and potential bioactivity of ethyl acetate extracts from 3 different Salvia species; Salvia absconditiflora (Salvia cryptantha- an endemic species), S. sclarea and S. palaestina collected from different localities in Anatolia. Total phenolic-flavonoid contents, antioxidant properties and enzyme inhibition experiments were investigated in tested Salvia species. The phenolic profiles were also determined by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analysis revealed the presence of phenolic compounds in ethyl acetate extracts such as cynaroside, rosmarinic acid, cosmosiin, luteolin, apigenin and acacetin. The highest level of phenolic components was detected in S. absconditiflora with 74.16 mg GAE/g. The best radical scavenging and reducing abilities were found in S. absconditiflora (DPPH: 251.39 mg TE/g; ABTS: 340.16 mg TE/g; CUPRAC: 496.20 mg TE/g; FRAP: 322.94 mg TE/g). Moreover, the inhibition of AChE, BChE, and α-amylase has also been studied. The most potent AChE inhibitory ability was recorded in S. sclarea (4.00 mg GALAE/g), followed by S. palaestina (3.38 mg GALAE/g) and S. absconditiflora (3.01 mg GALAE/g). The extracts exhibited similar amylase inhibitory effects. These results reveal that Salvia species [S. absconditiflora (S. cryptantha), S. sclarea and S. palaestina] confirming their potential can be rich sources of promising bioactive compounds as a starting point for further analysis. In addition, it is thought that this study may be the new report for the construction of helpful databases in terms of shedding light on future research and researchers with the valuable information obtained about these economically important Salvia species