Recent-onset ecstasy use: Association with deviant behaviors and psychiatric comorbidity.

Background: Despite increases in ecstasy (MDMA) use in the United States, little is known about characteristics linked with recent-onset ecstasy use, especially psychiatric symptoms and deviant behaviors. Aims: To test whether individuals with high levels of other drug use are more likely to be recent-onset ecstasy users; to test whether psychiatric symptoms in adults are associated with recent-onset ecstasy use; to explore the association between recent-onset ecstasy use and concomitant deviant behaviors in adolescents and adults. Methods: Data from the 2001 National Survey on Drug Use and Health. Findings: Recent-onset ecstasy use was significantly more likely to occur among adolescents and adults (18-34 years old) who engaged in deviant behaviors during the past year as compared with those who did not engage in deviant behaviors during the past year. Higher levels of deviancy indicated a higher likelihood of being a recent-onset ecstasy user, and associations were strongest with nonviolent deviant behaviors such as selling illegal drugs and stealing. Associations between deviant behaviors and recent-onset ecstasy use were similar in strength to associations between deviant behaviors and recent-onset cocaine and marijuana use, respectively. Adults who had past-year psychiatric symptoms (both depressive and panic symptoms) were twice as likely to be recent-onset ecstasy users as compared with those without past-year psychiatric symptoms. Greater levels of drug involvement increased the odds of being a recent-onset ecstasy user. Conclusion: Recent-onset ecstasy use seems to be associated with a range of other behavioral problems and may reflect one aspect of a larger problem behavior syndrome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of growth hormone in children with a GH deficiency: a report of 5 cases

The authors describe 5 cases, 3 boys and 2 girls, with idiopathic growth hormone deficiency in prepubertal age, treated with human growth hormone. In four of five cases the response to treatment with GH was relevant. Only in one case (F1) the response was negative. The results of this study confirm that rhGH is a safe and effective therapy in children with GHD.     

Inorganic–organic hybrid materials with zirconium oxoclusters as protective coatings on aluminium alloys

Inorganic–organic hybrid materials are attracting a strong scientific interest mainly for their outstanding inherent mechanical and thermal properties, which can be traced back to the intimate coupling of both inorganic and organic components. By carefully choosing the experimental parameters used for their synthesis, chemically and thermally stable acrylate-based hybrid material embedding the zirconium oxocluster Zr₄O₄(OMc)₁₂, where OMcCH₂C(CH₃)C(O)O, can be deposited as UV-cured films on aluminium alloys.

In particular, the molar ratios between the oxocluster and the monomer, the polymerisation time, the amount of photo-initiator and the deposition conditions, by using an home-made spray-coating equipment, were optimised in order to obtain the best performing layers in terms of transparency and hardness to coat aluminium alloy (AA1050, AA6060 and AA2024) sheets. Furthermore, it was also evaluated whether the hybrid coatings behave as barrier to corrosion.

Several coated samples were prepared and characterised. Environmental scanning electronic microscopy (ESEM) and scratch test were used to investigate the morphology of the films and to evaluate their scratch resistance, respectively. Electrochemical impedance spectroscopy (EIS) was performed in order to evaluate if the coatings actually protect the metallic substrate from corrosion.

In order to measure shear storage modulus (G′) and loss modulus (G″) of the materials used for coatings, bulk samples were also obtained by UV-curing of the precursors solution. Dynamical mechanical thermal analysis (DMTA) was performed in shear mode on cured disks of both the hybrid materials and pristine polymer for comparison. The values of T_g were read off as the temperatures of peak of loss modulus. The length and mass of all the samples were measured before and after the DMTA analysis, so that the shrinkage of the materials in that temperature range was exactly evaluated.     

Compositional constraints in the extremely GC-poor genome of Plasmodium falciparum

We have analyzed the compositional properties of coding (protein encoding) and non-coding sequences of Plasmodium falciparum, a unicellular parasite characterized by an extremely AT-rich genome. GC% levels, base and dinucleotide frequencies were studied. We found that among the various factors that contribute to the properties of the sequences analyzed, the most relevant are the compositional constraints which operate on the whole genome.     

Transient response of a microstrip line circuit excited by anexternal electromagnetic source

The transient voltages and currents induced by an external electromagnetic field along a microstrip line interconnecting active and/or passive components are studied by using a distributed-source transmission-line model. The influence of the angle of incidence as well as that of the microstrip geometrical and electrical parameters on the line response is analyzed. The instantaneous voltage and power induced on the loads by various types of pulse excitations are computed. Numerical results are obtained both for dispersive and nondispersive lines. A line feeding a transistor microwave amplifier is also considered. The results show the effects of the multiple reflections of the field inside the dielectric substrate and of the signal at the ends of the line. Indications of how to reduce the coupling between the external field and the considered structure are given     

The effect of physical exercise on the response to exertion in the elderly

BACKGROUND: A decrease in adaptation to exertion has been observed as age progresses. Although this decline may also be affected by factors such as health conditions and age, physical inactivity related to sedentary behaviour plays a dominant role. METHODS: In order to evaluate the influence of physical activity on cardiovascular response to exertion in the elderly, 4 groups of 22 subjects each were submitted to maximal electrocardiographic exercise test on a cycloergometer (multistage program with 30 Watts x 3 min. steps). All subjects were male. The composition of the groups was as follows: 1) veteran long distance runners (mean age: 71 +/- 5.4); 2) sedentary veterans (mean age: 69.8 +/- 3.9); 3) young long distance runners (mean age: 25.4 +/- 4.3); 4) sedentary young adults (mean age: 25.8 +/- 3.9). The endurance athletes, well fitted to competition, had been practicing sport activity for at least 3 years. RESULTS: Heart rate, arterial systolic and diastolic blood pressure were recorded; mean blood pressure and double product were calculated at baseline and at the climax of the stress test; furthermore, total and maximal watts were recorded. For each of the parameters, Student's t test for non-paired observations were used to evaluate statistical differences amongst the four groups. The most interesting result arises in the comparison between veteran long distance runners and sedentary young adults: between the two groups no statistically significant differences in workload, expressed as total watts (1649.55 +/- 296.32 vs 1650.00 +/- 446.32; p = NS) and maximal watts (175.91 +/- 19.19 vs 173.18 +/- 24.38; p = N.S.), were observed. On the contrary, highly significant differences in both total (p < 0.01) and maximal (p < 0.01) watts were noticed by comparing long distance runners and sedentary subjects of the same age. CONCLUSIONS: These data support the hypothesis that the progressive reduction in physical activity, which is usually observed in aging, is the major determinant of exercise deconditioning in the elderly.     

Mortar finite element discretization for the flow in a nonhomogeneous porous medium

Darcy’s equations model the flow of a viscous incompressible fluid in a rigid porous medium. One of the parameters of the system depends on the permeability of the medium and, when this medium is not homogeneous, the variations of the parameter could be very high. To handle this phenomenon, we propose a discretization of the model that relies on the mortar finite element method. Indeed, the idea is to construct a decomposition of the domain such that the permeability is constant on each element of the partition and to use independent meshes on the different subdomains. We perform the a priori and a posteriori analysis of this discretization and present some numerical experiments which are in good coherency with the results of the analysis.