A study on the behavior of laminated and sandwich composite plates using a layerwise theory

The numerical study of structures constituted from composite materials, regardless the underlying shear deformation theory used may be framed into an equivalent single-layer or a layerwise methodology. The adoption of one of these approaches is mainly ruled by the detail one needs to put in the description of the deformation kinematics and on the subsequent description of other relevant quantities such as stresses or frequencies. Being important to address both qualitative and quantitatively the influence of different parameters involved in the models and materials used to represent a structure, it is also relevant to understand how layerwise theories can predict its static and dynamic response. These different issues may be addressed by carrying out parametric studies to characterize the influence of specific parameters on the mechanical performance of sandwich and laminated composite plates. To this purpose a layerwise theory based on the first order shear deformation theory, is considered, and a set of different test cases are analyzed in light of this approach, providing results which may also be useful for later comparison purposes

Chemical composition and bioactivity of essential oils and extracts from Oregano from Madeira Island, Portugal

In the course of ongoing investigations on polymorphic Lamiaceae species, we studied Origanum vulgare spp. virens growing wild in several locations of Madeira Island, Portugal. Variation in essential oil composition with climate conditions was studied. The antimicrobial activity of the various essential oils was determined against 10 strains of bacteria and yeasts, usually found as human pathogenic or food contaminants. The essential oils inhibited all the bacteria tested excepting for P. aeruginosa. The most sensitive microorganism was M. smegmatis with MIC = 25 µg ml-1 for two of the oils. The results of this study suggest a potential application of these oils in preventing the human pathogenic and food contaminant microorganisms growth. Radical scavenging capacity of essential oils and solvent extract (hexane, chloroform, ethyl acetate and methanol) were also determined, since interest of oregano resides in both non polar and polar fractions, all known by their very high antioxidant activity. From the hexane fraction, we obtained a large amount of 1-hexacosanol, C26H54O, a long chain alcohol, which was previously extracted in the non-esterified form only from Hygrophila erecta.info:eu-repo/semantics/publishedVersio

Evaluation of zearalenone in vitro removal by Saccharomyces cerevisiae strains isolated from bovine forage

Zearalenone (ZEN) is a mycotoxin that has relatively low acute toxicity. However, it is a potent oestrogen, interfering with the reproductive tract of animals. Among other effects, ZEN decreases animals fertility, and induces fibrosis in the uterus, breast cancer and endometrial carcinoma (Zinedine et al., 2007). Anti-mycotoxin additives (AMA) are defined as a group of products that, when added to animal feed, are capable of adsorbing, inactivating, or neutralizing mycotoxins in the gastrointestinal tract of animals. One example of these products are adsorbents based on yeast cell walls, a safe and beneficial animal feed additive (Abreu et al., 2008). When based on active cells, yeast based products also act as a probiotic, contributing to improve the general animal health because it stimulates their immune system and promotes the integrity of intestinal mucosa (Albino et al., 2006). Strains of Saccharomyces cerevisiae isolated from silage were tested for their ZEN removal capability. Their effect on - and b-zearalenol (-ZOL and b-ZOL) was also tested. Strains were grown on YPD separately supplemented with ZEN, -ZOL and b-ZOL, and their elimination from culture media was quantified over time by HPLC-FL.This study was carried out with grants from CYTED (Acción 109ac0371), CNPq, CAPES-DS and FAPUR/UFRRJ (Brazil). Luís Abrunhosa was supported by grant SFRH/BPD/43922/2008 from Fundação para a Ciência e Tecnologia – FCT, Portugal.. Authors also acknowledge the support of the Society for Applied Microbiology – SfAM

Standardization of an enzyme-linked immunosorbent assay (Elisa) for the determination of avidity of avian IGY immunoglobulin.

Projeto/Plano de Ação: 11.11.11.111

Inhibitor of cysteine protease and mortality of Diaphorina citri.

The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), is considered an important pest of citrus by its ability to transmit the HLB disease. Thus, the aim of this study was to evaluate the potential of protease inhibitors for the control of this insect. The tests were performed with Murraya paniculata plants. The following aqueous solutions were applied: (1) distilled water (control), (2) Triton X-100 (0.1 m L-1) and (3) cysteine proteinase inhibitor E-64 (0.05 mg mL-1) and Triton X -100 (0.1 mL L-1). Four treatments were performed: solutions (1), (2) and (3) were applied four days before the release of the insects on the plants and for the last treatment, solution (3) was applied immediately before the insects release. The solutions were applied to the stem of the plant, 20 mL per plant. Were used five plants per treatment. Ten adults of D. citri were released on each plant after four hours of starvation. Each plant was maintained in a cage and mortality was observed for five days. The data was analyzed by Tukey test (p>0.05). There was no significant difference in mortality of insects among the treatments. Enzymatic analysis showed that there is enzymatic activity of cysteine p roteases in the D. citri midgut, thus, the low mortality after ingestion of this compound may indicate the need to adapt the bioassay method