Synthesis,characterization and antibacterial activity studies of poly-{styrene-acrylic acid} with silver nanoparticles

This work reports the preparation and characterization of copolymer poly-{styrene-acrylic acid} with monomeric ratio of styrene/acrylic acid of 9:1 using benzoyl peroxide as initiator and furthermore filled with nanosilver (25 ppm and 50 ppm) in water/acetone (1:40 v/v). The nanosilver emulsion was obtained from chemical reduction using NaBH₄ as reducing agent and sodium citrate as the stabilizer. The preparation of nanosilver emulsion was monitored by the appearance of a Plasmon Resonant Absorption band in a UV–visible spectrophotometer and the particles sizes were observed through TEM. Microbiological studies were performed to investigate the antimicrobial activity of this new material against the microorganisms Escherichia coli (ATCC-25922) and Staphylococcus aureus (ATCC-6538), used as reference strains. The antimicrobial activity of the poly-{styrene-acrylic acid} filled with nanosilver was confirmed by the presence of an inhibition halo of the bacterial growth in seeded culture media, but was not found with the poly(styrene-acrylic acid) alone. The present work suggests that silver ions are released from the polymeric matrix to the culture media and have the ability to tune the Ag⁺ ions released by controlling the amount of Ag nanoparticles embedded in the composite.     

Evaluation of the photoelectrocatalytic method for oxidizing chloride and simultaneous removal of microcystin toxins in surface waters

The production of chlorine was investigated in the photoelectrocatalytic oxidation of a chloride-containing solution using a TiO₂ thin-film electrode biased at current density from 5 to 50 mA cm⁻² and illuminated by UV light. Such parameters as chloride concentrations from 0.001 to 0.10 mol L⁻¹, pH 2-12, and interfering salts were varied in this study in order to determine their effect on this oxidation process. At an optimum condition this photoelectrocatalytic method can produce active chlorine at levels compatible to water disinfections processes using a chloride concentration higher than 0.010 mol L⁻¹ at a pH of 4 and a current density of 30 mA cm⁻². The method was successfully applied to treat surface water collected from a Brazilian river. After 150 min of photoelectrocatalytic oxidation, we obtained a 90% reduction in total organic carbon removal, a 100% removal of turbidity, a 93% decrease in colour and a chemical oxygen demand (COD) removal of around 96% (N = 3). The proposed technology based on photoelectrocatalytic oxidation was also tested in treating 250 mL of a solution containing 0.05 mol L⁻¹ NaCl and 50 μg L⁻¹ of Microcystin aeruginosa. The bacteria is completely removed after 5 min of photoelectrocatalysis following an initial rate constant removal of −0.260 min⁻¹, suggesting that the present method could be considered as a promising alternative to chlorine-based disinfections.     

Cytotoxicity study of some Ti alloys used as biomaterial

An implanted material is considered biocompatible, if adverse and uncontrollable reactions don't exist in the biological system. In this sense, biocompatibility tests made in the constituent materials are very important so that the implants have success. The in vitro cytotoxicity tests represent the initial phase of the process, and could be considered as a pre-selection of those materials. In vitro techniques using cell culture have become widely used in the evaluation of biomaterial cytotoxicity, which has contributed to their standardization and the substitution of in vivo tests. This paper shows a study of the in vitro cytotoxicity of two Ti based alloys, Ti–13Nb–13Zr and Ti–35Nb–7Zr–5Ta, in the as-received condition and after heat treated. The results show that the alloys presented no cytotoxic effects in the studied conditions.     

Treatment of industrial wastewater using zeolitite and sepiolite,natural microporous materials

This work investigates the ability of natural microporous materials, such as a zeolite-rich tuff (zeolitite) and a modulated phyllosilicate (sepiolite), to remove heavy-metal ions from simulated inorganic polluted industrial wastewater. Fixed beds of sepiolite and zeolitite were percolated by a solution of Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ (concentration of each cation, 2 ? 10^?3 N; total concentration, 10^?2 N) and were regenerated with a 2 ? 10^?3 N Na⁺ solution. The order of decreasing affinity was, for sepiolite: Cu²⁺ > Zn²⁺ > Cd²⁺ > Pb²⁺ ? Co²⁺, and, for zeolitite: Pb²⁺ “Cd²⁺ > Cu²⁺ > Zn²⁺ > Co²⁺. After regeneration with Na⁺ solution, a fraction of the retained heavy metals was quickly released by the beds as follows: sepiolite, Co²⁺ ? Pb²⁺ > Cd²⁺ > Zn²⁺ > Cu²⁺; zeolitite, Cd²⁺ > Cu²⁺ ? Zn²⁺ > Co²⁺ > Pb²⁺. XRD and DTA-TGA analyses examined structural changes in the natural and final materials.     

CDK4, CDK6/cyclin-D1 Complex Inhibition and Radiotherapy for Cancer Control: A Role for Autophagy

The expanding clinical application of CDK4- and CDK6-inhibiting drugs in the managements of breast cancer has raised a great interest in testing these drugs in other neoplasms. The potential of combining these drugs with other therapeutic approaches seems to be an interesting work-ground to explore. Even though a potential integration of CDK4 and CDK6 inhibitors with radiotherapy (RT) has been hypothesized, this kind of approach has not been sufficiently pursued, neither in preclinical nor in clinical studies. Similarly, the most recent discoveries focusing on autophagy, as a possible target pathway able to enhance the antitumor efficacy of CDK4 and CDK6 inhibitors is promising but needs more investigations. The aim of this review is to discuss the recent literature on the field in order to infer a rational combination strategy including cyclin-D1/CDK4-CDK6 inhibitors, RT, and/or other anticancer agents targeting G1-S phase cell cycle transition.     

Antiangiogenic properties of carotenoids: A potential role of maize as functional food

Several human disorders are associated with neovascularization. The current in vivo study examines the effect in the blood vessel formation of a xanthophyll-rich seed extract of maize. The angiostatic effects of treatment with maize seed carotenoid extract (0.1–10 μM of zeaxanthin equivalent/implant) were evaluated in the chick yolk sac membrane (YSM) (12–50% inhibition, P < 0.05) as well as in the chorioallantoic membrane (CAM) assay (23–52% inhibition, P < 0.05) as compared to control group. A similar inhibitory action was found by treatments with the retinoic acid (10 μM/embryo, 49% and 57% inhibition) and commercial lutein (10 μM/embryo, 65% and 55% inhibition) (positive controls) performed in the YSM and CAM, respectively. Results point to maize seeds as interesting sources of xanthophylls which effectively inhibited the process of vessel formation, suggesting a potential role of such compounds in the prevention of diseases associated with vascular dysfunction.     

Performances of time–temperature indicators in the study of temperature exposure of packaged fresh foods

The diffusion of time–temperature indicators (TTIs), attached as labels onto the packages of perishable food and non‐food products (intelligent packaging), is growing more and more. Aside from checking product shelf‐life, TTI devices can be used to monitor the distribution chain in real conditions. In this respect, the performances of some very common TTIs (A 12 Fresh Check, Lifelines Technologies) were extensively investigated in this work. The aim was to establish a procedure for an accurate, objective and reproducible estimate of the darkening progress of the sensitive area of the indicators and to discover a reliable data treatment to estimate the ‘effective temperature’, T_eff, namely a fictitious average temperature that can replace the overall temperature fluctuations experienced by a packaged fresh food. The image analysis approach was found very useful for an accurate and sensitive definition of the information provided by the indicators, leading to the evidence of a very slow darkening of the sensitive region, even at ?22°C. The kinetic parameterization of TTI responses was implemented in an EXCEL worksheet so as to directly evaluate T_eff on the basis of a set of label brightness values acquired by image analysis. Comparing the calculated ‘effective temperature’ with the average temperature recorded with conventional devices, the reliability of the TTI tags and the accuracy of this procedure was demonstrated. Taking into account the low cost of the TTI tags, their wide usage can be suggested to monitor the various steps of the real distribution chain of a given product, namely, transport, bench and home storage. Copyright © 2001 John Wiley & Sons, Ltd.     

Evidence that the effect of angiotensin II on bovine oocyte nuclear maturation is mediated by prostaglandins E2 and F2alpha

Angiotensin II (AngII) prevents the inhibitory effect of follicular cells on oocyte maturation, but its involvement in LH-induced meiotic resumption remains unknown. The aim of this study was to assess the involvement of AngII in LH-induced meiotic resumption and of prostaglandins (PGs) in the action of AngII. In the experiment I, seven cows were superovulated, intrafollicularly injected with 10 muM saralasin (a competitive AngII antagonist) or saline when the follicles reached a diameter larger than 12 mm, and challenged with a GnRH agonist to induce an LH surge. Fifteen hours after GnRH, the animals were ovariectomized and the oocytes were recovered to determine the stage of meiosis. The oocytes from follicles that received saline were in germinal vesicle (GV) breakdown (30.8%) or metaphase I (MI; 69.2%) stage while those that received saralasin were in the GV stage (100%; P<0.001) 15 h after GnRH agonist. In another experiment, oocytes were co-cultured with follicular hemisections for 15 h to determine whether PGs mediate the effect of AngII on meiotic resumption. Indomethacin (10 microM) inhibited AngII-induced meiotic resumption (13.4 vs 77.5% MI without indomethacin; P<0.001). Furthermore, the GV oocytes progressed to MI at a similar rate when PGE(2), PGF(2alpha) or AngII was present in the co-culture system with follicular cells (PGE(2) 77.4%, PGF(2alpha) 70.0%, and AngII 75.0% MI). In conclusion, our results provide strong evidence that AngII mediates the resumption of meiosis induced by an LH surge in bovine oocytes and that this event is dependent on PGE(2) or PGF(2alpha) produced by follicular cells.     

Safety approach in the EU test blanket systems design

This paper reveals the safety strategy and approach developed and followed in the design of the two EU TBS describing its objectives, components and implementation. Addressing the safety in the early stage of the conceptual design of nuclear facilities is a well recognized international practice and industrial project-level requirement for the successful completion of the licensing process within expected project cost and schedule. The impact of the early development of the safety approach, its implementation and monitoring in the design of nuclear device like the TBS is not limited to the safety assessment and licensing activities only. Safety approach plays indispensible role in reducing the overall project risk. It infiltrates the entire design process through the unavoidable interfaces between the design features and its safety level. In reality the entire process of the TBS development, design, technological demonstration and implementation is affected by the project team safety culture.