Effects of zinc on microalgal biofilms in intertidal and subtidal habitats

Microalgal biofilms are sensitive to environmental conditions. Impacts of contaminants on assemblages of marine biofilm are often investigated in laboratories or in mesocosms. Such experiments are rarely representative of the effects of contaminants on biofilms under natural conditions. Studies in field situations, with enough power to detect impacts, are necessary to develop a better understanding of the effects of contaminants on ecological processes. Metals are a common contaminant of marine systems and can cause disturbances to assemblages. Using a new technique to experimentally deliver contaminants to microalgal assemblages, hypotheses were tested regarding the effects of zinc on microalgal biofilms growing on settlement panels in subtidal and intertidal habitats. PAM fluorometry was used to assess the amount and physiological state of biofilms on panels. Control panels deployed for 1 month in each habitat had significantly greater amounts of biofilm than those exposed to zinc. After deployment for 3 months, the results varied with location. The observed effects on the biofilm did not, however, cause significant changes in the macro-invertebrate assemblages that developed on the panels

Development of casein micellar pediatric formulations

Poster presented at the 1st European Conference on Pharmaceutics. 13-14 April 2015, Reims, France."The current need for medicines specifically designed for children, which consider ease of administration, dose flexibility, palatability, safety of excipients, stability and therapeutic equivalency of pediatric dosage forms, has driven the development of pediatric drug formulations. In the present work casein (CN) based micellar formulations are evaluated as vehicles for the oral delivery of pediatric drugs, since caseins are nontoxic, biodegradable, GRAS materials and nanoencapsulation of drugs can improve their bioavailability. Chemical crosslinking of casein by carbodiimide (EDC) has been studied as an approach to improve the stability of the CN micelles and to tailor drug release."Fundação para a Ciência e a Tecnologia, Portugal (Research grant PTDC/DTPFTO/1057/2012

Evaluation of the ability of powdered milk to produce mini-tablets containing paracetamol

Poster presented at the 1st European Conference on Pharmaceutics. 13-14 April 2015, Reims, France"In recent years the development of medicines for paediatric use have gained increase interest. Small, flexible solid dosage forms, such as mini-tablets, are an attractive choice when developing new medicines for children. Excipients, though innocuous in adults, may pose a threat to the different paediatric age groups and, therefore, milk, a complete, universally accepted food, used in children’s diet since birth, seems to be an innovative and attractive excipient when formulating for the aforementioned population. In this study a full factorial design was employed to identify the variables (both formulation and manufacturing) and their interactions with significant impact on selected properties of mini-tablets, containing paracetamol and powdered milk, produced by direct compression."Fundação para a Ciência e a Tecnologia (PTDC/DTP-FTO/1057/2012

The role of translational invariance in non linear gauge theories of gravity

The internal structure of the tetrads in a Poincar\'e non linear gauge theory of gravity is considered. Minkowskian coordinates becomes dynamical degrees of freedom playing the role of Goldstone bosons of the translations. A critical length allowing a covariant expansion similar to the weak field approach is deduced, the zeroth order metric being maximally symmetric (Minkowskian in some cases).Comment: 17 pages, LaTe

Comment on the Adiabatic Condition

The experimental observation of effects due to Berry's phase in quantum systems is certainly one of the most impressive demonstrations of the correctness of the superposition principle in quantum mechanics. Since Berry's original paper in 1984, the spin 1/2 coupled with rotating external magnetic field has been one of the most studied models where those phases appear. We also consider a special case of this soluble model. A detailed analysis of the coupled differential equations and comparison with exact results teach us why the usual procedure (of neglecting nondiagonal terms) is mathematically sound.Comment: 9 page

On the Electronic Transport Mechanism in Conducting Polymer Nanofibers

Here, we present theoretical analysis of electron transport in polyaniline based (PANi) nanofibers assuming the metalic state of the material. To build up this theory we treat conducting polymers as a special kind of granular metals, and we apply the quantum theory of conduction in mesoscopic systems to describe the transport between metallic-like granules. Our results show that the concept of resonance electron tunneling as the predominating mechanism providing charge transport between the grains is supported with recent experiments on the electrical characterization of single PANi nanofibers. By contacting the proposed theory with the experimental data we estimate some important parameters characterizing the electron transport in these materials. Also, we discuss the origin of rectifying features observed in current-voltage characteristics of fibers with varying cross-sectional areas.Comment: 5 pages, 1 figure, accepted for publication in Phys. Rev. B, Vol.72, xxxx (2005

Desempenho de injetores tipo Venturi em condições de descarga livre e pressurizada.

O objetivo deste trabalho foi avaliar características hidráulicas e condições operacionais que influem no desempenho de injetores trabalhando em condições de descarga livre e pressurizada e em diferentes condições de vazão e pressões motrizes

HPLC determination of theophylline and paracetamol in fresh and powdered milk

Poster presented at the 1st International Congress of CiiEM - From Basic Sciences to Clinical Research. 27-28 November 2015, Egas Moniz, Caparica, Portugal"Theophylline and paracetamol are drugs used worldwide both in human and veterinary medicine. Paracetamol (or acetaminophen) is employed as analgesic and antipyretic, and theophylline is a bronchodilator drug used in the treatment of asthma and chronic obstructive pulmonary disease. Both drugs are extensively used in pediatrics and their dosage is based on the child's body weight. Due to possible liver toxicity (paracetamol) and narrow therapeutic index (theophylline) it is imperative to carefully select and monitor the dose administered to children. Additionally, the recent proposal of milk as a platform to deliver drugs in pediatrics has prompted the development of a simple and sensitive high-performance liquid chromatography (HPLC) quantification method, of both theophylline and paracetamol, in the complex matrix that milk represents."Fundação para a Ciência e a Tecnologia (PTDC/DTP-FTO/1057/2012

Normalization procedure for relaxation studies in NMR quantum information processing

NMR quantum information processing studies rely on the reconstruction of the density matrix representing the so-called pseudo-pure states (PPS). An initially pure part of a PPS state undergoes unitary and non-unitary (relaxation) transformations during a computation process, causing a "loss of purity" until the equilibrium is reached. Besides, upon relaxation, the nuclear polarization varies in time, a fact which must be taken into account when comparing density matrices at different instants. Attempting to use time-fixed normalization procedures when relaxation is present, leads to various anomalies on matrices populations. On this paper we propose a method which takes into account the time-dependence of the normalization factor. From a generic form for the deviation density matrix an expression for the relaxing initial pure state is deduced. The method is exemplified with an experiment of relaxation of the concurrence of a pseudo-entangled state, which exhibits the phenomenon of sudden death, and the relaxation of the Wigner function of a pseudo-cat state.Comment: 9 pages, 5 figures, to appear in QI

Chemical Evolution of the Galaxy Based on the Oscillatory Star Formation History

We model the star formation history (SFH) and the chemical evolution of the Galactic disk by combining an infall model and a limit-cycle model of the interstellar medium (ISM). Recent observations have shown that the SFH of the Galactic disk violently variates or oscillates. We model the oscillatory SFH based on the limit-cycle behavior of the fractional masses of three components of the ISM. The observed period of the oscillation ($\sim 1$ Gyr) is reproduced within the natural parameter range. This means that we can interpret the oscillatory SFH as the limit-cycle behavior of the ISM. We then test the chemical evolution of stars and gas in the framework of the limit-cycle model, since the oscillatory behavior of the SFH may cause an oscillatory evolution of the metallicity. We find however that the oscillatory behavior of metallicity is not prominent because the metallicity reflects the past integrated SFH. This indicates that the metallicity cannot be used to distinguish an oscillatory SFH from one without oscillations.Comment: 21 pages LaTeX, to appear in Ap