Strength improvement of adhesively-bonded joints using a reverse-bent geometry

Adhesive bonding of components has become more efficient in recent years due to the developments in adhesive technology, which has resulted in higher peel and shear strengths, and also in allowable ductility up to failure. As a result, fastening and riveting methods are being progressively replaced by adhesive bonding, allowing a big step towards stronger and lighter unions. However, single-lap bonded joints still generate substantial peel and shear stress concentrations at the overlap edges that can be harmful to the structure, especially when using brittle adhesives that do not allow plasticization in these regions. In this work, a numerical and experimental study is performed to evaluate the feasibility of bending the adherends at the ends of the overlap for the strength improvement of single-lap aluminium joints bonded with a brittle and a ductile adhesive. Different combinations of joint eccentricity were tested, including absence of eccentricity, allowing the optimization of the joint. A Finite Element stress and failure analysis in ABAQUS® was also carried out to provide a better understanding of the bent configuration. Results showed a major advantage of using the proposed modification for the brittle adhesive, but the joints with the ductile adhesive were not much affected by the bending technique

Candida clinical species identification : molecular and biochemical methods

In the last decade, the number and diversity of nosocomial Candida infections has increased significantly, resulting in an emergent need for rapid and accurate methods for Candida identification. Therefore, the aim of this study was to evaluate the performance of three biochemical systems (Auxacolor, ID32C, and Vitek 2 YST) for the identification of Candida species, comparing them with molecular identification (polymerase chain reaction and gel agarose electrophoresis). These methods were used to assess Candida spp. (229 clinical isolates) prevalence and distribution among clinical specimens. The biochemical methods with higher percentages of correct identification were Vitek 2 YST (79.6%) and Auxacolor (78.6%). However, overall the biochemical methods assayed differed from the molecular identification. Thus, due to their rapid and precise identification, molecular methods are promising techniques for Candida species identification in clinical laboratories. Candida albicans and Non Candida albicans Candida species had a similar prevalence (50.4 and 49.6%, respectively), corroborating the epidemiological shift observed for these pathogens in the recent years

Methodology evaluation of pin microrelief meter

The effects of natural weathering and different managements performed in agriculture may best be understood by studying the soil roughness. The aim of this study was to evaluate the optimization of the use of pin microrelief meter, an instrument used to determine the soil surface roughness, as the number of readings collected over traditional methodology proposed in the bibliography. The study was conducted in Rio Paranaiba (MG), in a Haplustox soil. The experimental design was completely randomized in a 2×3 factorial design with four replications. There were combined two types of primary tillage: conventional tillage with disc plow (PCAD) and harrow (PCGA), and three amounts of readings (100, 200, and 300 reading points) sampled in each experimental unit. Independently of the soil tillage, disc plow and harrow, the collection of 100 readings using a pin microrelief meter of a square meter, was sufficient to determine the surface roughness before and after soil preparation, without accuracy loss compared with the traditional method

In vitro study of the antifungal potential of Glycyrrhiza glabra L. against Candida species

In the last two decades, an increasing incidence of opportunistic fungal infections has been observed, not only at hospital level but also in the community. Candida albicans was identified as the main responsible agent for those infections, but other non-Candida albicans Candida (NCAC) species have also been associated with this complicated medical condition [1]. Furthermore, higher rates of fungal resistance to the current drugs have been observed and are still growing, making the discovery of new active antifungal substances very urgent. Medicinal plants can be explored for that purpose. Glycyrrhiza glabra L. is commonly used in folk medicine due to its antimicrobial and antiviral activities, as well as for a wide variety of dermal affections [2]. Some reports have described the antimicrobial potential of licorice (G. glabra roots), namely aqueous extracts [e.g., 3]. Herein, the antifungal potential of the hydroalcoholic extract prepared from rhizomes and roots of G. glabra, was evaluated against 19 Candida strains, using the disc diffusion halo assay. The licorice extract was effective against all the tested C. albicans, C. glabrata, C. parapsilosis and C. tropicalis strains. It is very interesting to highlight the broad spectrum of activity of this extract, for which were observed similar results into different strains of the same species and even between different species. The results for the inhibitory zones, at the tested concentration (50 mg/mL), after 24h, were 1.0-1.2 cm for C. albicans and C. parapsilosis, 1.0-1.3 cm for C. tropicalis and 1.2 cm for C. glabrata, maintaining the potential at 48h and even at 72h. This study demonstrates that G. glabra hydroalcoholic extract probably exerts mainly fungicidal and not so much fungistatic effects, and it could find applications in antifungal therapy. Nevertheless, further studies will be performed in order to characterize the extract, namely on phenolic composition, and to elucidate its mechanism of action

Glycyrrhiza glabra L. as a promisor candidacidal in biofilms and planktonic cells: comparison between phenolic extract and isolated compounds

Opportunistic fungal infections, particularly involving Candida species (candidiasis) have become a serious prob- lem of public health. Current antifungal agents have been loosing the effectiveness, in part due to their overuse, and appearance of resistant Candida species. Plants have been used over years and recommended by natural physicians for multitude of health conditions. The aim of the present study was to evaluate the anti-Candida potential of a hydrometh- anolic extract of rhizomes and roots of Glycyrrhiza glabra L. (licorice), in planktonic cells and biofilms, as well as to compare its effect with individual phenolic compounds identified in the extract. Licorice extract evidenced an antifungal activity against all of the nineteen tested Candida strains, including C. al- bicans, C. glabrata, C. parapsilosis and C. tropicalis species. The inhibition zones varied between 10-13 mm; MIC and MFC values varied, between 0.375-1.5 and 0.75-3 mg/mL for planktonic cells and biofilms, respectively. Considering the pronounced antifungal activity, a chemical characterization of the extract was conducted, and the main phenolic compounds identified were tested. Flavones (mainly apigenin derivatives), flavanones (mainly liquiritin derivatives), an isoflavone and a chalcone, were the most abundant compounds. However, these compounds were not active neither individually nor combined. Thus, probably synergistic effects among all components in the phenolic pool and/or other compounds present in the extract should be responsible for the observed antifungal activity. Detailed in vivo studies should be performed, not only to evaluate the actual effects in a complete organism, but also the safety of the preparation and bioavailability in systemic infection models

In vivo anti-Candida activity of phenolic extracts and compounds: future perspectives focusing effective clinical interventions

Candida species have increasingly deserved a special attention among the medical community. In spite of its presence as a human commensal, alarming rates of local and systemic infections have been observed, varying from moderate to severe impact. Currently available antifungal drugs have progressively lost its effectiveness, pointing urgently the problem of the microorganisms with acquired-resistance. Natural matrices are secularly used for numerous purposes, being inclusive highly effective as antimicrobials. Increasing evidences give a particular emphasis to the contribution of phenolic extracts and related individual compounds. In vitro studies clearly confirms its prominent effects, but the confirmation through in vivo studies, including the involved mechanisms of action are not so much deepen. Therefore, the present reports aims to provide an extensive knowledge about all these aspects, highlighting the most efficient phytochemical formulations, including therapeutic doses. Further studies need to be incited to deepen knowledge on this area, namely focused on clinical trials to provide safer and more effective antimicrobials than the current ones.The authors are grateful to Foundation for Science and Technology (FCT, Portugal) for N. Martins Grant (SFRH/BD/87658/2012), L. Barros researcher contract under "Programa Compromisso com Ciencia-2008," and financial support to the research centre CIMO (strategic project PEst-OE/AGR/UI0690/2014). This work was also supported by the Programa Operacional, Fatores de competitividade-COMPETE and by national funds through FCT (Fundacao para a Ciencia e a Tecnologia) on the scope of the Projects FCT PTDC/SAU-MIC/119069/2010, RECI/EBB-EBI/0179/2012, and PEst-OE/EQB/LA0023/2013. The authors thank the Project "BioHealth-Biotechnology and Bioengineering approaches to improve health quality," Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON. 2-O Novo Norte), QREN, and FEDER

In vitro study of the antifungal potential of Apiaceae hydroalcoholic extracts against Candida species

The use of medicinal plants is an ancient practice, but recently there is an increasing interest towards the evaluation of their bioactive properties. Opportunistic fungal infections, linked with higher rates of fungal resistance to the current antifungal drugs, have deserved special relevance in the last decades. Candida albicans was identified as the main responsible agent for those infections, but other non-Candida albicans Candida (NCAC) species have been also found [1]. Thus, it is urgent to discover new alternatives against those pathogens with high resistance. In the present work, the antifungal potential of hydroalcoholic extracts obtained from two Apiaceae plants (Coriandrum sativum L. and Pimpinella anisum L.), commonly used in folk medicine, were evaluated against a total of 19 Candida strains (from the species: C. albicans, C. glabrata, C. parapsilosis and C. tropicalis). The fruits of Coriandrum sativum L. (coriander) and Pimpinella anisum L. (anise) showed similar antifungal potential considering the studied strains, being effective against three of the nineteen strains. However, regarding the tested Candida species, the extracts presented considerable variations. Whereas coriander was effective against C. parapsilosis (ATCC22019 and 513143) and C. tropicalis (ATCC750), anise was effective against C. parapsilosis (513143 and 491861) and C. albicans (558234). Furthermore, the inhibitory zones were different at 24 and 48h. Further studies are being carried out in order to characterize the mechanism of action and the compounds responsible for the bioactivity, but the use of these extracts seems to have potential in antifungal therapy. REFERENCES [1] Martins N, Ferreira ICFR, Barros L, Silva S, Henriques M. (2014). Mycopathol. 177, 223–240.Instituto Nacional de Saúde Dr. Ricardo Jorg

A semiautomated microfluidic platform for real-time investigation of nanoparticles' cellular uptake and cancer cells' tracking

Aims: develop a platform composed of labeled dendrimer nanoparticles and a microfluidic device for real-time monitoring of cancer cells fate. Materials and Methods: The physicochemical and biological characterization of the developed Carboxymethyl-chitosan/poly(amidoamine) (CMCht/PAMAM) dendrimer nanoparticles were performed using TEM, AFM, Zeta Sizer, DSC and cytotoxicity screening. Cancer cell lines derived from different tumor types, including HeLa (Cervical Carcinoma), HCT-116 (Colon Carcinoma) and U87MG (Glioblastoma), were exposed to different concentrations of CMCht/PAMAM dendrimer nanoparticles over a period of 3 days (MTS/DNA). Results: Nanoparticles were successfully modified with an average size of 50 nm. Internalization levels go from 87% to 100% in static and from 95% to 100% in dynamic conditions. Viability levels range from 95% to 100% in static and from 90% to 100% in dynamic conditions, being HCT the most sensitive to the presence of the NP. Conclusions: the results show different responses to the presence of 0.5 mg.mL-1 dendrimer nanoparticles when comparing static to dynamic conditions, with a tendency towards higher sensitivity when subjected to confinement. This work demonstrated that the proposed microfluidic-based platform allows real-time cell monitoring, which, upon more studies, namely the assessment of the drug release effect, could be used for cancer theranostics.FR Maia acknowledges ERC-2012-ADG 20120216–321266 (ComplexiTE) for her Postdoc scholarship. JM Oliveira thanks Portuguese Foundation for Science and Technology (FCT) for his distinction attributed under the FCT Investigator program (IF/00423/2012). BM Costa also thanks Portuguese Foundation for Science and Technology (PTDC/SAU-GMG/113795/2009 and IF/00601/2012 to BM Costa), Fundação Calouste Gulbenkian (BM Costa) and Liga Portuguesa Contra o Cancro (BM Costa). MR Carvalho also thanks the funding through the LA ICVS/3Bs project (UID/Multi/50026/2013). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.info:eu-repo/semantics/publishedVersio

Natural extracts from wild flowers used in Portuguese folk medicine like a new antifungal agents against Candida species

The prevalence of opportunistic fungal infections has been increasing dramatically over the recent decades mainly due to the boom of the AIDS epidemic, increasing number of immunocompromised patients and the commonly use of indwelling medical devices. Although Candida albicans has been regarded as the most common causative agent of fungal infection in humans, nowadays other non-Candida albicans Candida (NCAC) species such as Candida glabrata, Candida tropicalis and Candida parapsilosis, are emerging as significant nosocomial pathogens and with high level of resistance to certain antifungal drugs. So, in the last years the interest in natural compounds has raised, specifically some phenolic extracts which have been known in folk medicine as antimicrobial agents. Thus, this work aimed to perform a screening of the antifungal potential of phenolic extracts of Castanea sativa, Filipendula ulmaria and Rosa micrantha flowers from Northeastern Portugal, against Candida species. The extracts were exhaustively characterized by HPLC-DAD-ESI/MS. Hydrolysable tannins were the main group of phenolic compounds in C. sativa and F. ulmaria samples, while flavonoids including procyanidins were the most abundant group in R. micrantha (6090 ± 253 mg/Kg). The minimal inhibitory concentration (MIC) was determined according with the guidelines in National Committee for Clinical Laboratory Standards (NCCLS, M27-A2 document) with some modifications. All extracts revealed promising antifungal effect, with MIC values ranging from concentrations under 0.05 to 0.625 mg/ml. R. micrantha extract showed a strong effect (MIC ≤ 0.155mg/ml) against the four strains assayed. Furthermore, it is also possible to assume that was against C. glabrata and C. parapsilosis that the phenolic extracts showed the highest activity (MIC <0.05mg/ml). Finally, the natural extracts effect was assessed on biofilm formation and on pre-formed biofilms by total biomass quantification using CV staining (1%, v/v). F. ulmaria and R. Micrantha were causative agent of important inhibition and destruction of C. tropicalis biofilms. In summary, the significant antifungal activity of C. sativa, F. ulmaria and R. micrantha revealed in this work, suggest that they could serve as a source of compounds with therapeutic potential against Candida-related infections

Antifungal activity of natural extracts from Northeastern Portuguese flowers against Candida biofilms

In healthy individuals, many species of Candida are endogenous commensals of the gastrointestinal and urogenital tracts. However, the prevalence of opportunistic fungal infections (candidosis) has been increasing dramatically over the recent decades and this is particularly evident in immunocompromised individuals. The importance of candidosis is the potential synergistic effect on virulence and subsequent difficulties encountered in treatment. Moreover, a major virulence factor of Candida is its ability to adapt to a variety of different habitats and the consequent formation of surface attached microbial communities known as biofilms. The resistance of Candida biofilms to antifungal agents was first demonstrated by Hawser et al., 1995. Although most episodes of candidosis are attributed to C. albicans, nowadays non-Candida albicans Candida (NCAC), such as C. glabrata, C. tropicalis and C. parapsilosis have emerged as important pathogens and tend to be inherently less susceptible to commonly used antifungal agents. So, in the last years the interest in natural compounds has increased, specifically some phenolic extracts which have been known in folk medicine as antimicrobial agents. Thus, this work aimed to preform a screening of the antifungal potential of phenolic extracts from Castanea sativa, Filipendula ulmaria and Rosa micrantha flowers against Candida biofilms. The extracts were exhaustively characterized by HPLC-DAD-ESI/MS. Hydrolysable tannins were the main group of phenolic compounds in C. sativa and F. ulmaria samples, while flavonoids were the most abundant group in R. micrantha (6090 ± 253 mg/Kg). The minimal inhibitory concentration (MIC) was determined according to the guidelines in NCCLS document M27-A2 with some modifications. All extracts revealed promising antifungal effect, with MIC values ranging from concentrations under 0.05 to 0.625 mg/ml. R. micrantha extract showed a strong effect (MIC ≤ 0.155mg/ml) against all strains tested and, it is also possible to assume that was against C. glabrata and C. parapsilosis that the phenolic extracts showed the highest activity (MIC <0.05mg/ml). Finally, the natural extracts effect was assessed on biofilm formation and on pre-formed biofilms by total biomass quantification using CV staining (1%, v/v). F. ulmaria and R. micrantha were causative agents of important inhibition and destruction of C. tropicalis biofilms. In summary, the significant antifungal activity evident in this work of C. sativa, F. ulmaria and R. micrantha, advise that they could be used as a source of compounds with therapeutic potential against Candida-related infections caused by biofilms