Design and characterization of PNVCL-based nanofibers and evaluation of their potential applications as scaffolds for surface drug delivery of hydrophobic drugs

In this work, nanofiber scaffolds for surface drug delivery applications were obtained by electrospinning poly(N-vinylcaprolactam) (PNVCL) and its blends with poly(ε-caprolactone) and poly(N-vinylcaprolactam)-b-poly(ε-caprolactone). The process parameters to obtain smooth and beadless PNVCL fibers were optimized. The average fibers diameter was less than 1 μm, and it was determined by scanning electron microscopy analyses. Their affinity toward water was evaluated by measuring the contact angle with water. The ketoprofen release behavior from the fibers was analyzed using independent and model-dependent approaches. The low values of the release exponent (n < 0.5) obtained for 20 and 42 °C, indicating a Fickian diffusion mechanism for all formulations. Dissolution efficiencies (DEs) revealed the effect of polymer composition, methodology used in the electrospinning process, and temperature on the release rate of ketoprofen. PNVCL/poly(N-vinylcaprolactam)-b-poly(ε-caprolactone)-based nanofibers showed greater ability to control the in vitro release of ketoprofen, in view of reduced kinetic constant and DE, making this material promising system for controlling release of hydrophobic drugs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48472.     

Study of the influence of notch radii and temperature on the probability of failure: A methodology to perform a combined assessment

The fracture assessment of notched components based on cracked components approaches leads to over‐conservative failure predictions. In the research literature, several approaches are proposed to overcome this problem using an apparent fracture toughness, . Nevertheless, most of these approaches are based on deterministic assumptions despite the large and variable scatter exhibited by for different notch radii (ρ) or temperatures (T). This paper proposes a methodology for deriving a probabilistic field including the effect of temperature on the failure of notched components. First, the theory of critical distances is applied to transform each apparent fracture toughness into the equivalent fracture toughness for ρ = 0. Then, the temperature is supposed to act as a scale effect in the Weibull cumulative distribution function of the equivalent fracture toughness, and the corresponding scale effect function is derived. Finally, the applicability of the proposed methodology is illustrated by an example using two ferritic‐pearlitic steels: S275JR and S355J2.     

Ketotifen controlled release from cellulose acetate propionate and cellulose acetate butyrate membranes

Ketotifen was immobilised in cellulose acetate propionate (CAP) membranes and in cellulose acetate butyrate (CAB) membranes. The characteristics of each system were evaluated under a range of experimental conditions. The topography and uniformity of the membranes was assessed using scanning electron microscopy. The release characteristics associated with Ketotifen were monitored spectrophotometrically. The swelling capacity of the membranes was evaluated and attributed to the combined effects of diffusion and of complex dissociation, during swelling. The materials produced were able to provide controlled release of Ketotifen due to their controlled swelling behaviour and adequate release properties. The results showed that the release of Ketotifen from the CAB membranes is higher but the release from the CAP membranes is more uniform.     

Scientific publications from non-academic sectors and their impact

Scientometrics - Universities are not the only institutions that publish scientific papers. In this study we evaluate the production and impact of scientific publications from non-academic and...     

International collaboration in Brazilian science: financing and impact

Scientometrics - The study of international collaborations can help in understanding the benefits of such relationships and aid in developing national financing policies. In this paper, the...     

Production profiles in Brazilian Science,with special attention to social sciences and humanities

Scientometrics - The impact and interaction of science with society is difficult to measure, especially at a national level. In this study, data collected for the quadrennial evaluation...     

Coherence Between Superconducting Edge States in Superconducting Periodic Arrays of Artificial Defects

The transition line of superconducting arrays of holes exhibits a rich field structure due to the interference of superconducting states nucleated at the holes edges. We studied by means of resistance measurements their effect on the T* _c (H) line as a function of transverse magnetic field using regular arrays of nanofabricated micron size holes. The arrays transition fields are higher than for the bulk. Moreover we found a nontrivial field modulation of the T* _c (H) line with an inversion, with increasing field, of the modulation concavity which we assigned to a crossover from a collective to an isolated edge state regime. The high field regime is well described by the nucleation at a single hole in an infinite film. The modulation at low fields was found to be dominated by the interference of neighbor edge states when the inter-hole distance w becomes comparable to the coherence length (T* _c ). A comparison between arrays of different hole shape shows the influence of geometry on the type of interaction established, which can described either as a superconducting wire network or as a weak link array.     

Environmental considerations in energy planning for the Amazon region: Downstream effects of dams

The most salient current feature of the electric energy sector in Brazil is the pressing need for expansion. In this context, the hydroelectric resources of the Amazon region are considered a competitive alternative despite the structural problems they entail. These include reliance of new investments and environmental restrictions. Concerning the latter, plans to build large-scale dams in the region have drawn criticism mainly on account of the loss of forest cover in areas flooded by dam reservoirs and the conflicts concerning the relocation of indigenous and riverside communities in the region. This article seeks to contribute to better understanding of the environmental issue in the Amazon by focusing attention on the downstream effects of dams, which have large-scale, hitherto neglected ecological repercussions. The impact of dams extends well beyond the area surrounding the artificial lakes they create, harming rich Amazon wetland ecosystems. The morphology of dammed rivers changes in response to new inputs of energy and matter, which may in turn destroy certain biotopes. This is a remote-sensing-based case study of the Tucuruí hydroelectric scheme in the Amazon state of Pará. Attention is drawn to the need to take into account effects on alluvial rivers downstream from hydroelectric power plants when it comes to making planning decisions, as part of a sustainable energy policy.     

Smoking Consequences Questionnaire—Spanish.

A total of 212 Spanish smokers completed a Spanish version of a smoking questionnaire based on the Smoking Consequences Questionnaire—Adult (A. L. Copeland, T. H. Brandon, & E. P. Quinn, 1995) and a nicotine dependence (ND) measure. Confirmatory factor analysis results supported an a priori defined 8-factor structure. The results also indicated good internal consistency for the instrument and the scales derived from each factor. Positive outcome smoking expectancies scales were significantly and substantially associated with ND scores. Also, after controlling for the influence of ND, the authors found higher smoking expectancies in women than in men in (a) weight control, (b) craving reduction and addictiveness, and (c) negative-affect reduction. The results support the instrument's construct validity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)