Oxygen plasma functionalization of parylene C coating for implants surface: Nanotopography and active sites for drug anchoring

The effect of oxygen plasma treatment (t = 0.1–60 min, p_O2 = 0.2 mbar, P = 50 W) of parylene C implant surface coating was investigated in order to check its influence on morphology (SEM, AFM observations), chemical composition (XPS analysis), hydrophilicity (contact angle measurements) and biocompatibility (MG-63 cell line and Staphylococcus aureus 24167 DSM adhesion screening). The modification procedure leads to oxygen insertion (up to 20 at.%) into the polymer matrix and together with surface topography changes has a dramatic impact on wettability (change of contact angle from θ = 78 ± 2 to θ = 33 ± 1.9 for unmodified and 60 min treated sample, respectively). As a result, the hydrophilic surface of modified parylene C promotes MG-63 cells growth and at the same time does not influence S. aureus adhesion. The obtained results clearly show that the plasma treatment of parylene C surface provides suitable polar groups (C = O, C–O, O–C = O, C–O–O and O–C(O)–O) for further development of the coating functionality.     

An optimization approach to establish an appropriate energy group structure for BWR pin-by-pin core analysis

An optimization approach to establish an appropriate multi-group energy structure for boiling water reactor (BWR) pin-by-pin fine mesh core analysis is proposed. In the present approach, the number of energy groups of cross sections is successively reduced or increased. In order to select an energy group boundary that is removed or added, performances of all possible candidates of energy group structures are tested in multi-assembly geometries. Then, the energy group boundary, which provides the minimum difference of the k-infinity or the pin-by-pin fission rate distribution, is finally removed or added. This procedure is repeated until the number of energy groups reaches to the target value. In order to confirm the applicability of the present approach, the accuracies of the k-infinity and the pin-by-pin fission rate distribution are investigated in various 2 × 2 multi-assembly geometries with the established energy group structure. From the verification results, the differences of the k-infinity and the pin-by-pin fission rate distribution between the reference (fine) and the established (coarse) energy group structure are small in the various 2 × 2 multi-assembly geometries. Therefore, we can conclude that the present approach is efficient to establish an appropriate energy group structure for BWR pin-by-pin fine mesh core analysis.     

Phase separation and dewetting in polystyrene/poly(vinyl methyl ether) blend thin films in a wide thickness range

Phase separation and dewetting processes of blend thin films of polystyrene (PS) and poly(vinyl methyl ether) (PVME) in two phase region have been studied in a wide film thickness range from 65 μm to 42 nm (∼2.5R_g, R_g being radius of gyration of a polymer) using optical microscope (OM), atomic force microscope (AFM) and small-angle light scattering (LS). It was found that both phase separation and dewetting processes depend on the film thickness and were classified into four thickness regions. In the first region above ∼15 μm the spinodal decomposition (SD) type phase separation occurs in a similar manner to bulk and no dewetting is observed. This region can be regarded as bulk. In the second region between ∼15 and ∼1 μm, the SD type phase separation proceeds in the early stage while the characteristic wavelength of the SD decreases with the film thickness. In the late stage dewetting is induced by the phase separation. In the third region between ∼1 μm and ∼200 nm the dewetting is observed even in the early stage. The dewetting morphology is very irregular and no definite characteristic wavelength is observed. It is expected that the irregular morphology is induced by mixing up the characteristic wavelengths of the phase separation and the dewetting. In the fourth region below ∼200 nm the dewetting occurs after a long incubation time with a characteristic wavelength, which decreases with the film thickness. It is considered that the layered structure is formed in the thin film during the incubation period and triggers the dewetting through the capillary fluctuation mechanism or the composition fluctuation one.     

Measurements of complex refractive indices of metals at several wavelengths by frustrated total internal reflection due to surface plasmon resonance

By employing a modified Otto's configuration for measuring surface plasmon resonance that has been proposed by Bliokh and his coworkers [Appl. Phys. Lett.89, 021908 (2006)APPLAB0003-695110.1063/1.2220540] we have obtained complex refractive indices of metals at several wavelengths. We demonstrate that the configuration has high potential for obtaining dispersion relations of metal conductors in bulk samples as well as in thin films from the visible to the near-infrared wavelength region. Furthermore, we show that the configuration enables us to obtain the complex refractive indices of metals or a thickness or refractive index of a dielectric layer on the metal at different points simultaneously. We have constructed a measurement system and carried out basic experiments. The experimental results agreed well with numerically simulated values or published ones.     

Chemical composition of currant seed extracts and their protective effect on human lymphocytes DNA

On the basis of LC/UV/MS analysis, 35 compounds from the extracts of seeds of black, red, and white currants (2 cultivars of each) were identified. Black currants cultivars contained protocatechuic acid and p-hydroxybenzoic acid, and traces of nitril containing phenolic acids. The presence of synapoyl glucoside was characteristic for cv. Malling Jewel. Sesquiterpenoid glycosides and carboxymethylindol glycosides were present mainly in white and red currant cultivars. Blackcurrant seeds contained higher amounts of flavonoids, especially rutin, isoquercetin, and taxifolin. The currant seed extracts were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay. The frequency of MN was scored in binucleated cells, and the cultivars of black currants showed the best antioxidant potential. At a concentration of only 0.17 mg/mL, extract of the seed cv. Malling Jewel effected a decrease in the frequency of MN of 60% compared with control cell cultures. PRACTICAL APPLICATION: Our results provide evidence of protective effects of currant seed extracts and isolated pure compounds on cytogenetic damages in human lymphocytes. Thus, currant seed extracts could exert beneficial effects in quite a few diseases, for many of the biological actions have been attributed to their antioxidant properties.     

The age of cows as a factor shaping the antioxidant level during a nutritional experiment with fish oil and linseed supplementation for increasing the antioxidant value of milk

BACKGROUND: So far, in research studies, the age of cows has not been considered as a factor that may influence the changes in the content of milk ingredients with antioxidant properties modified by the feed supplementation. The aim of this study was to determine the influence of supplementation on the content of ingredients having antioxidant properties and to determine the influence of the age of cows taking part in the experiment on these changes. The experiment was conducted using 20 Polish Holstein Friesian cows, 10 primiparous and 10 multiparous. The combined supplementation of fish oil and linseed constituted the experimental factor. RESULTS: The milk of primiparous cows after 21 days of supplementation was characterised by a higher content of C18:1 trans ‐11, C18:2 cis ‐9, trans ‐11, α‐retinol, α‐tocopherol and β‐lactoglobulin compared to the milk of multiparous cows, in which a higher level of lactoferrin, C20:5 and β‐carotene was recorded. In both groups an increase in the total antioxidant status was noted (a higher level in the milk of primiparous cows). CONCLUSIONS: Modification of the diet of cows with fish oil and linseed significantly influenced antioxidant properties of their milk; however, the response of multiparous and primaparous cows was noticeably different to the supplement introduced. Copyright © 2012 Society of Chemical Industry     

Cytoprotective activity of extract of roasted coffee residue on mouse embryonic fibroblasts cells against apoptosis induced by oxidative stress

This study was conducted to evaluate the cytoprotective activity of roasted coffee residues (RCRs) extract on mouse embryonic fibroblast (MEF) cells. RCRs originated from Colombia and Honduras are relatively nontoxic to cell growth and even stimulate cell proliferation. Colombian RCRs showed most efficient protective effects on MEF cells against oxidative damage induced by H₂O₂ compared among the extracts prepared under the same roasting time. The most significant radical scavenging activity was measured in RCR with roasting time of 8.5 min. Phenolic and nonphenolic compounds in RCRs were chlorogenic acid, caffeine, caffeic acid, nicotinic acid, trigonelline, and 5-(hydroxymethyl)furfuralolehyde. Effect of Colombian RCRs on apoptosis occurred by oxidative damage was evaluated by morphological and flow cytometric analysis. Apoptotic cell accumulation was decreased by cotreatment of MEF cells with Colombian RCRs. These results suggested that antioxidant potency of RCRs suppresses the cytotoxicity which is induced by H₂O₂ and has a protective effect on MEF cell against oxidative stress.     

Dioxin-like and transthyretin-binding compounds in indoor dusts collected from Japan: average daily dose and possible implications for children

Many researchers are increasingly interested in human exposure to house dust containing household compounds such as polybrominated diphenylethers (PBDEs). Nevertheless, no investigations have addressed the endocrine-disrupting potencies of compounds contained in indoor dust. This study specifically addresses endocrine-disrupting potencies such as dioxin-like activity and human transthyretin (TTR)-binding potencies. Using in vitro bioassays, we investigated these activity levels in indoor dusts. We performed exposure assessments of active compounds that are contained in house dust for subsequent evaluation of house dusts' risks to humans. Dioxin-like and TTR-binding activities in sulfuric acid treatment extracts of house and office dust were investigated using Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) and TTR-binding assay (in vitro competitive human TTR-binding assay). Dioxin-like activities in indoor dust were 38-1400 pg CALUX-TEQ (2,3,7,8-TCDD equivalent)/g (median 160 pg CALUX-TEQ/g) and TTR-binding potencies were 300-5000 pmol T4EQ (thyroxine (T4) equivalent)/g (median 1000 pmol T4EQ/g), which are higher values than those in other environmental samples, e.g., contaminated sediments. These exposure results suggest that children might be affected by both dioxin-like compounds and TTR-binding compounds via house dust. When the ingestion rate, CALUX-TEQ, and T4EQ for house dust are high, thyroid hormone homeostasis in children may be disrupted.     

Belite cement clinker from coal fly ash of high Ca content. Optimization of synthesis parameters

The optimization of parameters of synthesis of belite cement clinker from coal fly ash of high Ca content is presented in this paper. The synthesis process is based on the hydrothermal-calcination-route of the fly ash without extra additions. The hydrothermal treatment was carried out in demineralized water and a 1 M NaOH solution for 4 h at the temperatures of 100 degrees C, 150 degrees C, and 200 degrees C. The precursors obtained during the hydrothermal treatmentwere heated at temperatures of 700 degrees C, 800 degrees C, 900 degrees C, and 1000 degrees C. The changes of fly ash composition after the different treatments were characterized by X-ray diffraction (XRD), FT infrared (FTIR) spectroscopy, surface area (BET-N2), and thermal analyses. From the results obtained we concluded that the optimum temperature of the hydrothermal treatment was 200 degrees C, and the optimum temperature for obtaining the belite cement clinker was 800 degrees C.     

Color measurement: comparison of colorimeter vs. computer vision system

The aim of this work was to compare two food color measurement techniques, the traditional tristimulus colorimeter and an image analysis system. In this sense a computer vision system was developed, consisting of a digital camera, a controlled illumination environment, and a software package to process the images. The conversion between color spaces was performed employing empirical mathematical models; a standard color chart was used for its calibration. The color of 40 samples of raw and processed foods was measured in the CIELAB color space with the computer vision system and a colorimeter. The equivalence between both techniques, for individual L*, a* and b* values, was determined using appropriate hypothesis tests. For most samples both systems provide equivalent results, although the total color difference ?Ε was high enough to be noticeable. The average ?Ε was 5.88?±?3.32, with an average absolute ?L*?=?2.79?±?2.42, ?a*?=?3.02?±?2.94; ?b*?=?2.84?±?2.53. In addition, the color measured by the image analyses technique seemed to be more similar to the real ones.