Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Breeding Pools Utilized by the Puerto Rican Crested Toad, Peltophryne lemur.

Habitat preservation and management may play an important role in the conservation of the Puerto Rican crested toad, Peltophryne lemur, due to this species' small geographic range and declining native wild population. Bioavailable water concentrations of Polycyclic Aromatic Hydrocarbon (PAH) contaminants within breeding pools at 3 sites were established using Passive Sampling Devices (PSDs) and gas chromatography-mass spectrometry (GC/MS). A more diverse population of PAH analytes were found in higher concentrations at the breeding site that allowed direct vehicular access, but calculated risk quotients indicated low risk to toad reproduction associated with the current PAH analyte levels

High-cycle electromechanical aging of dielectric elastomer actuators with carbon-based electrodes

We present high-cycle aging tests of dielectric elastomer actuators (DEAs) based on silicone elastomers, reporting on the time-evolution of actuation strain and of electrode resistance over millions of cycles. We compare several types of carbon-based electrodes, and for the first time show how the choice of electrode has a dramatic influence on DEA aging. An expanding circle DEA configuration is used, consisting of a commercial silicone membrane with the following electrodes: commercial carbon grease applied manually, solvent-diluted carbon grease applied by stamping (pad printing), loose carbon black powder applied manually, carbon black powder suspension applied by inkjet-printing, and conductive silicone-carbon composite applied by stamping. The silicone-based DEAs with manually applied carbon grease electrodes show the shortest lifetime of less than 105 cycles at 5% strain, while the inkjet-printed carbon powder and the stamped silicone-carbon composite make for the most reliable devices, with lifetimes greater than 107 cycles at 5% strain. These results are valid for the specific dielectric and electrode configurations that were tested: using other dielectrics or electrode formulations would lead to different lifetimes and failure modes. We find that aging (as seen in the change in resistance and in actuation strain versus cycle number) is independent of the actuation frequency from 10 Hz to 200 Hz, and depends on the total accumulated time the DEA spends in an actuated state

“Nós familiares: O desentrelaçar das famílias de origem”. O papel da diferenciação do self no compromisso e na desilusão relacional

Dissertação de Mestrado apresentada no Ispa – Instituto Universitário para obtenção do grau de Mestre na especialidade de Psicologia Clínica.O presente estudo teve como principal objetivo investigar o papel mediador da Diferenciação do Self e dos seus diversos componentes (e.g.: Reatividade Emocional, Fusão com Outros, Cut-off Emocional e Posição do Eu) na relação entre a Transgeracionalidade e o Compromisso. Paralelamente, procurou estudar a relação entre a Diferenciação do Self e a Desilusão Relacional. Com efeito, 192 participantes, envolvidos numa relação amorosa há pelo menos uma ano, foram recrutados online através do método de amostragem da “bola de neve", para responderem aos seguintes instrumentos: Escala dos Legados da Família de Origem (ELFO), Inventário da Diferenciação do Self – Revisto (IDS-R), Inventário de Componentes de Qualidade Relacional Percebida (IPRQC) e Escala de Desilusão Relacional (EDR). No que respeita aos resultados mais salientes, o presente estudo indica uma relação significativa entre a Transgeracionalidade e o Compromisso, concluindo que apenas o Cut-off Emocional e a Posição do Eu medeiam significativamente esta relação, explicando aproximadamente 7.4% e 8.10% da variabilidade do Compromisso, respetivamente. Por outro lado, o estudo evidencia correlações negativas e significativas entre as pontuações globais da Diferenciação do Self, as respetivas dimensões e a Desilusão Relacional. Em suma, estes resultados reforçam a influência das famílias de origem no compromisso amoroso. Mais concretamente, o estudo propõe um caminho através do qual, indivíduos com dificuldades em se diferenciarem das suas famílias de origem, podem se comprometer em relacionamentos futuros. Por fim, e tendo em conta as descobertas contrárias à literatura científica, são avançadas hipóteses explicativas para a relação encontrada entre o Cut-off, Reatividade Emocional, Fusão com outros e a Desilusão Relacional.ABSTRACT: The purpose of this study was to investigate the mediating role of Differentiation of Self (D.o.S) and its various components (e.g.: Emotional Reactivity, Fusion with Others, Emotional Cut-off and I Position) in the relationship proposed between Family Transmission and Commitment. In addition, the study also aimed to understand the association between D.o.S and Relationship Disillusionment. To this extent, 192 participants involved in a romantic relationship for at least a year, were recruited online via “snowball sampling” to answer the following instruments: Family of Origin Legacy Scale (ELFO), Differentiation of Self Inventory – Revised (DSI-R), Inventory of Perceived Relationship Quality Components (IPRQC) and Relationship Disillusionment Scale (RDS). The most noteworthy results revealed a significant relationship between Family Transmission and Commitment, therefore concluding that only Emotional Cut-off and I Position were significant mediators in this relationship, explaining approximately 7.4% and 8.10% of the variability in Commitment, respectively. On the other hand, the study indicates negative and significant correlations between global D.o.S scores as well as all respective dimensions and Relationship l Disillusionment. In sum, these findings reinforce the notion that families of origin influence relationship commitment. More precisely, this study suggests a pathway through which individuals that have difficulties in differentiating themselves from the family of origin can commit to future relationships. Lastly, in the sample of this study, all dimensions of D.o.S are found to be negatively associated with Relationship Disillusionment, which proves contrary to the literature, regarding dimensions of Emotional Cut-off, Reactivity and Fusion with others. Explanatory hypotheses are therefore discussed

Pretreatment with Ursodeoxycholic Acid (UDCA) as a Novel Pharmacological Intervention in Hepatobiliary Scintigraphy

The purpose of this volunteer study was to investigate whether pretreatment with UDCA before the administration of 99mTc DISIDA affects the biliary excretion of the DISIDA, and whether it can shorten the total imaging time. Ten young, healthy volunteers (eight males, two females, mean age: 26.3 ± 2.1 years) participated in the study. Hepatobiliary scintigraphies were performed twice per volunteer within three days, for the control and the UDCA-pretreated studies. In the control study, the gallbladder (GB) was observed first in four cases and the intestine was observed first in another four cases; in contrast, in the UDCA challenge study, the GB was observed first in eight cases. The quantitative results for the factors related to the GB differed significantly between the control and challenge studies. When the subjects were pretreated with UDCA, the time duration until visualization of the GB was shortened, and the maximum activity of the GB became more intense. In conclusion, UDCA pretreatment before hepatobiliary scintigraphy can shorten the total imaging time for evaluating functional obstructions of the cystic duct and increase the specificity of the process

Synthesis and anti-HIV activity of thiocholesteryl-coupled phosphodiester antisense oligonucleotides incorporated into immunoliposomes

Encapsulation of oligonucleotides in antibody-targeted liposomes (immunoliposomes) which bind to target cells permits intracellular delivery of the oligonucleotides. This approach circumvents problems of extracellular degradation by nucleases and poor membrane permeability which free phosphodiester oligonucleotides are subject to, but leaves unresolved the inefficiency of encapsulation of oligonucleotides in liposomes. We have coupled oligonucleotides to cholesterol via a reversible disulfide bond. This modification of oligonucleotides improved their association with immunoliposomes by a factor of about 10 in comparison to unmodified oligonucleotides. The presence of cholesteryl-modified oligonucleotides incorporated in the bilayer of liposomes did not interfere with the coupling of the targeting protein to the liposome surface. Free or cholesterol coupled oligonucleotides associated with liposomes and directed against the tat gene of HIV-1 were tested for inhibition of HIV-1 proliferation in acutely infected cells. We demonstrate that the cholesteryl-modified as well as unmodified oligonucleotides acquire the target specificity of the antibody on the liposome. Their antiviral activity when delivered into cells is sequence-specific. The activity of these modified or unmodified oligonucleotides to inhibit the replication of HIV was the same on an equimolar basis (EC50 around 0.1 μM). Cholesterol coupled oligonucleotides thus offer increased liposome association without loss of antiviral activity

Hydrogen atom in a spherical well: linear approximation

We discuss the boundary effects on a quantum system by examining the problem of a hydrogen atom in a spherical well. By using an approximation method which is linear in energy we calculate the boundary corrections to the ground-state energy and wave function. We obtain the asymptotic dependence of the ground-state energy on the radius of the well.Comment: Revised version to appear in European Journal of Physic