Lack of mutagenic effect by multi-walled functionalized carbon nanotubes in the somatic cells of Drosophila melanogaster

AbstractCarbon nanotubes (CNTs) are formed by rolling up a single graphite sheet into a tube. Among the different types of CNTs, the multi-walled carbon nanotubes (MWCNTs) comprise a set of concentric nanotubes with perfect structures. Several uses for MWCNTs have been suggested to be included in biological applications such as manufacturing of biosensors, carriers of drugs. However, before these materials can be put on the market, it is necessary to know their genotoxic effects. Thus, this study aims to evaluate the mutagenicity of multi-walled carbon nanotubes (MWCNTs) functionalized in somatic cells of Drosophila melanogaster, using the somatic mutation and recombination test (SMART). This assay detects the loss of heterozygosity of marker genes expressed phenotypically on the wings of the fly. Larvae of three days were used, resulting from ST cross, with basal levels of the cytochrome P450 and larvae of high metabolic bioactivity capacity (HB cross). They were treated with different concentrations of MWCNTs functionalized. The MH descendants, analyzed in both ST and HB crosses, had no significant effects on the frequency of mutant. Based on the results and on the experimental conditions mentioned in this study, it was concluded that MWCNTs were not mutagenic in D. melanogaster

Magnetic Field Dependent Behavior of the CDW ground state in Per2M(mnt)2 (M = Au, Pt)

The Per2M(mnt)2 class of organic conductors exhibit a charge density wave (CDW) ground state below about 12 K, which may be suppressed in magnetic fields of order 20 to 30 T. However, for both cases of counter ion M(mnt)2 species studied (M = Au (zero spin) and M = Pt (spin 1/2)), new high field ground states evolve for further increases in magnetic field. We report recent investigations where thermopower, Hall effect, high pressure and additional transport measurements have been carried out to explore these new high field phases.Comment: 6 pages, 10 figures, 27 reference

Tackling the cell wall of the grape berry

Abstract: The cell wall (CW) is the dynamic border of plant cells. In grape berries, the CW decisively accounts for the difference between the pulp and skin cells, with direct consequences on the grape characteristics, wine quality and wine-making methods. The softening of mature berries results from the depolymerisation and solubilisation of CW polymers. Modifications of grape pulp and skin CW provide the flexibility for cell expansion during fruit growth and to modulate the final texture. Wine making and berry processing methods are directly related with the absence, in white wines, or the presence, in red wines, of skin CW in the fermenting must. Anthocyanin extraction depends directly on skin yielding of the pigment upon CW degradation. During fruit growth and ripening, the cooperative action between different enzyme families is capital in CW metabolism. The sequencing and public availability of the Vitis genome allowed us to focus on individual pathways, to profile the expression pattern of isoforms associated with each tissue, developmental phase or stress response, anticipating the effects on berry (and wine) production and quality. Retrieving the sequences of genomic coding regions and the predicted enzymes that act on the Vitis, CW allows us for the first time to tackle the grape berry Cell Wallom

Mechanical behaviour of dental composite filling materials using digital holography

One of the most common clinical problems in dentistry is tooth decay. Among the dental filling materials used to repair tooth structure that has been destroyed by decay are dental amalgam and composite materials based on acrylics. Dental amalgam has been used by dentists for the past 150 years as a dental restorative material due to its low cost, ease of application, strength, durability, and bacteriostatic effects. However its safety as a filling material has been questioned due to the presence of mercury. Amalgam possesses greater longevity when compared to other direct restorative materials, such as, composite [1]. However, this difference has decreased with continual development of composite resins [2]

Greenhouse watching system using multi-technologies

Traditional agriculture uses empiric methods and is very exposed to meteorological conditions. To increase the agriculture production, greenhouses had appeared to allow crops with higher quality. Greenhouses also permit the study of cause-effect concepts that by them allow building models that improve the crop’s production and quality. Based on this reality, this paper presents a system developed by researchers of two schools of the Instituto Politécnico of Castelo Branco(IPCB) to monitor a greenhouse located in the campus of Escola Superior Agrária (ESA). This proposed system uses several different technologies

Bounds on the electromagnetic interactions of excited spin-3/2 leptons

We discuss possible deviations from QED produced by a virtual excited spin-3/2 lepton in the reaction $e^+e^- \longrightarrow 2\gamma$. Data recorded by the OPAL Collaboration at a c.m. energy $\sqrt{s} = 183 GeV$ are used to establish bounds on the nonstandard-lepton mass and coupling strengths.Comment: Latex, 5 pages, 7 ps figures. To be published in Phys. Rev.

The Safe-Port project: an approach to port surveillance and protection

SAFE-PORT is a recently started project addressing the complex issue of determining the best configurations of resources for harbour and port surveillance and protection. More specifically, the main goal is to find, for any given scenario, an adequate set of configuration solutions — i.e., number and type of sensors and equipments, their locations and operating modes, the corresponding personnel and other support resources — that maximize protection over a specific area. The project includes research and development of sensors models, novel algorithms for optimization and decision support, and a computer-based decision support system (DSS) to assist decision makers in that task. It includes also the development of a simulation environment for modelling relevant aspects of the scenario (including sensors used for surveillance, platforms, threats and the environment), capable to incorporate data from field-trials, used to test and validate solutions proposed by the DSS. Test cases will consider the use of intelligent agents to model the behaviour of threats and of NATO forces in a realistic way, following experts’ definitions and parameters

Multidimensional continued fractions, dynamical renormalization and KAM theory

The disadvantage of `traditional' multidimensional continued fraction algorithms is that it is not known whether they provide simultaneous rational approximations for generic vectors. Following ideas of Dani, Lagarias and Kleinbock-Margulis we describe a simple algorithm based on the dynamics of flows on the homogeneous space SL(2,Z)\SL(2,R) (the space of lattices of covolume one) that indeed yields best possible approximations to any irrational vector. The algorithm is ideally suited for a number of dynamical applications that involve small divisor problems. We explicitely construct renormalization schemes for (a) the linearization of vector fields on tori of arbitrary dimension and (b) the construction of invariant tori for Hamiltonian systems.Comment: 51 page

Estudo do comportamento mecânico dos compósitos de restauro dentário utilizando técnicas ópticas

Os materiais compósitos são hoje em dia cada vez mais utilizados no restauro dentário. Estes materiais substituíram as tradicionais amálgamas que apresentavam alguns inconvenientes. Apesar das vantagens no uso destes novos materiais existem ainda alguns problemas a resolver, nomeadamente a sua contracção durante o processo de cura. Desta forma surgem tensões nos dentes restaurados, podendo originar dano estrutural. Pretende-se com este trabalho estudar o processo de contracção dos compósitos dentários utilizando as técnicas ópticas, holografia digital, ESPI e correlação de imagem que demonstraram estar bem adaptadas a este estudo. É ainda apresentado um estudo comparativo utilizando diferentes materiais compósitos, bem como um estudo numérico com simulação por elementos finitos