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- Author or Editor: L. M. Fernández x
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Volumetric properties of 1-iodoperfluorohexane+n-octane binary system at several temperatures
Experimental data and EoS prediction
Abstract
New densities are reported over the whole composition range for 1-iodoperfluorohexane+n-octane system at temperatures from 288.15 to 308.15 K at atmospheric pressure. These data have been used to compute the excess molar volumes, V m E. Large positive V m E values have been obtained over the entire range of composition, which increases when the temperature rises. The experimental data were used to calculate the isobaric thermal expansivity, and the quantities (∂V m E/∂T)p and (∂H m E/∂p)T. Furthermore, the results have been used to investigate the volumetric prediction ability of the equations of state Soave–Redlich–Kwong, Peng–Robinson, Patel–Teja and Soave–Redlich–Kwong with volume translation.
Abstract
The thermal behaviour of a new kind of hybrid system based on silanized poly(ether-urethanes) (SPURs) has been analyzed by thermogravimetric analysis (TG). The influence of the chemical nature of employed alkoxysilanes, polyether diol molecular weight and the physical state of the obtained hybrids (cured and non-cured) has been studied. The results show that in the non-cured state, aminosilane-based systems present a higher stability compared with those based on isocyanatesilane. However, in the cured state, both types of hybrids present a similar thermal stability, but much higher than their corresponding partners before the curing process. The presence of the inorganic silica network improves the thermal stability of all the systems studied.
An important molecular-phylogenetic monography appeared about the Chiococceae tribe of the Caribbean region by Paudyal et al. (2018) proposing several new taxonomic modifying decisions concerning also to the monographic treatment of the recently (2017) published Rubiáceas de Cuba, as the confirmation and extension of the genus Solenandra revalidated by Borhidi (2002) and the separation of the new endemic Cuban genus Ramonadoxa Paudyal and Delprete from Chiococca. The molecular-phylogenetic studies did not verify the separation of Ceuthocarpus Aiello from Schmidtottia Urb. neither Phyllacanthus Hook. f. as independent genus from Catesbaea L.
Abstract
The kinetics of a poly(methyl methacrylate) (PMMA)-modified epoxy resin cured with different functionalities amine mixtures was analyzed using differential scanning calorimetry (DSC) in both isothermal and dynamic conditions. A delay in the reaction rate was observed which increased with PMMA content. An approach of kinetic features involved in curing was carried out. A linear dependence of preexponential factors of neat systems with modifier content was considered. The approach shows the contribution of other factors including the dilution effect of the functional groups to the observed delay. Fourier transform infrared spectroscopy (FTIR) indicated a noticeable change in the interactions present in neat systems due to the presence of PMMA. On the other hand, a significant influence of the ratio between each amine in the epoxy/amine mixtures on the final physical appearance was observed. At constant curing conditions, materials from completely opaque (phase separated) to transparent (miscible) were obtained with the increase in monoamine content.
The authors carried out a taxonomic study and revised and identified about 7,000 herbarium sheets of the genera Palicourea and Psychotria preserved in the collections of the Academy of Sciences of Cuba (HAC) and of the National Botanical Garden of Cuba (HAJB) with the purpose to complete the manuscript in preparation for the volume of the Rubiaceae Family of the Flora of Cuba. The results are as follows: Recognized 20 species of the genus Palicourea and 59 species of Psychotria. Revalidated 4 species new to the Flora of Cuba: Palicourea brachystigma Urb., Psychotria brevinodis Urb., Psychotria earlei Urb. and Psychotria tubulocubensis Govaerts. Established 3 new combinations: Palicourea ekmanii (Urb.) Borhidi et Oviedo, Palicourea odorata (Wr. ex Griseb.) Borhidi et Oviedo and Psychotria costivenia subsp. clementis (Britt.) Borhidi et Oviedo. Recognized and described 9 species and 1 subspecies of the genus Psychotria new to science: P. bissei Borhidi et Oviedo, P. brittonii Oviedo et Borhidi, P. ermitensis Borhidi et Oviedo, P. cromophila Oviedo et Borhidi, P. oblongicarpa Borhidi et Oviedo, P. pulchrinervis Borhidi et Oviedo, P. reflexiloba Borhidi et Oviedo, Psychotria reflexipes Borhidi et Oviedo, Psychotria rubens Borhidi et Oviedo, Psychotria costivenia subsp. wrightiana Borhidi et Oviedo. Following the concept of C. W. Hamilton (1989) recognised 10 species groups, 5 of them identical with the described ones from Mexico and Central America: the carthagenensis group with 4 species, the costivenia group with 10 species, the graciliflora group with 9 species, the nervosa group with 3 and the tenuifolia group with 1 species. Furthermore, the authors established 5 new groups, characteristic for the Greater Antillean flora: cathetoneura group with 4 species, the evenia group with 7 species, the lasiophthalma group with 4 species, the revoluta group with 10 species and the shaferi group with 9 species.
Including gaming disorder in the ICD-11: The need to do so from a clinical and public health perspective
Commentary on: A weak scientific basis for gaming disorder: Let us err on the side of caution (van Rooij et al., 2018)
The proposed introduction of gaming disorder (GD) in the 11th revision of the International Classification of Diseases (ICD-11) developed by the World Health Organization (WHO) has led to a lively debate over the past year. Besides the broad support for the decision in the academic press, a recent publication by van Rooij et al. (2018) repeated the criticism raised against the inclusion of GD in ICD-11 by Aarseth et al. (2017). We argue that this group of researchers fails to recognize the clinical and public health considerations, which support the WHO perspective. It is important to recognize a range of biases that may influence this debate; in particular, the gaming industry may wish to diminish its responsibility by claiming that GD is not a public health problem, a position which maybe supported by arguments from scholars based in media psychology, computer games research, communication science, and related disciplines. However, just as with any other disease or disorder in the ICD-11, the decision whether or not to include GD is based on clinical evidence and public health needs. Therefore, we reiterate our conclusion that including GD reflects the essence of the ICD and will facilitate treatment and prevention for those who need it.
