Interaction of a Long Alkyl Chain Protic Ionic Liquid and Water

A combined experimental/theoretical approach has been used to investigate the role of water in modifying the microscopic interactions characterizing the optical response of butyl-ammonium nitrate (BAN) water solutions. Raman spectra, dominated by the signal from the protic ionic liquid, were collected as a function of the water content, and the corresponding spatial organization of the ionic couples, as well as their local arrangement with water molecules, was studied exploiting classical molecular dynamics calculations. High quality spectroscopic data, combined with a careful analysis, revealed that water affects the vibrational spectrum BAN in solution: as the water concentration is increased, peaks assigned to stretching modes show a frequency hardening together with a shape narrowing, whereas the opposite behavior is observed for peaks assigned to bending modes. Calculation results clearly show a nanometric spatial organization of the ionic couples that is not destroyed on increasing the water content at least within an intermediate range. Our combined results show indeed that small water concentrations even increase the local order. Water molecules are located among ionic couples and are closer to the anion than the cation, as confirmed by the computation of the number of H-bonds which is greater for water-anion than for water-cation. The whole results set thus clarifies the microscopic scenario of the BAN-water interaction and underlines the main role of the extended hydrogen bond network among water molecules and nitrate anions.Comment: 27 pages, 10 figure

Operatori integro-differenziali di Langevin

In questo elaborato si studiano i processi stocastici con salti, si descrive il legame che esiste fra equazioni differenziali stocastiche con salti e gli operatori integro-differenziali, in analogia con il caso diffusivo. Si esplicita la funzione caratteristica dei processi con salti che siano somma di integrali di funzioni deterministiche, con l'interesse di comprendere quando si abbia l'esistenza di una densità. In particolare si studiano il processo di salto-diffusione e il processo soluzione dell'equazione di Langevin con salti

The intramolecular aldol condensation of 3-oxocyclohexaneacetaldehydes: A useful tool in the synthesis of natural products

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Step economy in the stereoselective synthesis of functionalized oxindoles via organocatalytic domino/one-pot reactions

Oxindoles are an important class of heterocyclic scaffolds widely present in natural products and bioactive compounds. For this reason, a plethora of methodologies for the stereoselective synthesis of enantioenriched oxindoles has been studied over the years. Among all the reported synthetic strategies, organocatalysis has proven to be a powerful tool for the asymmetric synthesis of this class of compounds being a step- and atom-economical, environmentally friendly, and non-toxic approach. This review will outline the application of asymmetric organocatalysis in the synthesis of chiral oxindole-based structures, relying on domino/one-pot reaction sequences in a step-economical fashion

The Influence of Investors’ Risk Attitude and Market Information on Cryptocurrency Investment: Evidence from an Experimental Study

The existing studies underline the relationship between individual behavior and market information on investment decisions. However, to our knowledge, few studies investigated this relationship in the field of cryptocurrencies. Cryptocurrencies are hybrid assets with high volatility. This paper explores the impact of investors’ risk attitude and market information on cryptocurrency investment using an experimental research design. We employed 185 Master students in our experiment. We tested our model through a probit regression, and results indicate that investors’ risk attitudes and market information positively impact investment in cryptocurrencies. Our study contributes to behavioral finance literature on risk attitude and market information related to crypto-currencies

Stemarane diterpenes and diterpenoids

In this article the scientific activity carried out on stemarane diterpenes and diterpenoids, isolated over the world from various natural sources, was reviewed. The structure elucidation of stemarane diterpenes and diterpenoids was reported, in addition to their biogenesis and biosynthesis. Stemarane diterpenes and diterpenoids biotransformations and biological activity was also taken into account. Finally the work leading to the synthesis and enantiosynthesis of stemarane diterpenes and diterpenoids was described

Role of ionic liquids in protein refolding: native/fibrillar versus treated lysozyme

Several ionic liquids (ILs) are known to revert aggregation processes and improve the in vitro refolding of denatured proteins. In this paper the capacity of a particular class of ammonium based ILs to act as refolding enhancers was tested using lysozyme as a model protein. Raman spectra of ILs treated fibrillar lysozyme as well as lysozyme in its native and fibrillar conformations were collected and carefully analyzed to characterize the refolding extent under the effect of the IL interaction. Results obtained confirm and largely extend the earlier knowledge on this class of protic ILs and indicate Ethyl Ammonium Nitrate (EAN) as the most promising additive for protein refolding. The experiment provides also the demonstration of the high potentiality of Raman spectroscopy as a comprehensive diagnostic tool in this field.Comment: 11 pages, 6 figures, 3 table

Novel locally active estrogens accelerate cutaneous wound healing-part 2

Estrogen deprivation is associated with delayed healing, while estrogen replacement therapy (ERT) accelerates acute wound healing and protects against development of chronic wounds. However, current estrogenic molecules have undesired systemic effects, thus the aim of our studies is to generate new molecules for topic administration that are devoid of systemic effects. Following a preliminary study, the new 17β-estradiol derivatives 1 were synthesized. The estrogenic activity of these novel compounds was evaluated in vitro using the cell line ERE-Luc B17 stably transfected with an ERE-Luc reporter. Among the 17β-estradiol derivatives synthesized, compounds 1e and 1f showed the highest transactivation potency and were therefore selected for the study of their systemic estrogenic activity. The study of these compounds in the ERE-Luc mouse model demonstrated that both compounds lack systemic effects when administered in the wound area. Furthermore, wound-healing experiments showed that 1e displays a significant regenerative and anti-inflammatory activity. It is therefore confirmed that this class of compounds are suitable for topical administration and have a clear beneficial effect on wound healing

Click-connected 2-(hydroxyimino)aldehydes for the design of UV-responsive functional molecules

Click chemistry is used to functionalize simple lipophilic and water-soluble molecules, a complex PEGylated phospholipid (DSPE-PEG2000), and two benzylic substrates with the 2-(hydroxyimino)aldehyde (HIA) group. To this end, two terminal alkynes bearing the HIA moiety were synthesized and coupled to different azides through copper(I)-catalyzed azide alkyne cycloaddition (CuAAC). Norrish–Yang photoisomerization (λ= 365 nm, LED source) is successfully obtained, with no interference by the triazole linker, except when the forbidden n-π* carbonyl transition is screened by a remote substituent such as salicylaldehyde. UV-Vis spectrometry suggests a specific interaction of HIAs with Cu(II), whereas no such evidence is found with Cu(I). We thereby show that the CuAAC methodology can be used successfully to obtain HIA-based UV-responsive hydrophilic or lipophilic ligands, phospholipidic components for the construction of liposomes, and macrocycle precursors. © 2020 Wiley-VCH Gmb

Marine heat waves detection in climate warming seas: their evolution in the NW Mediterranean sea

Ponencia presentada en: XII Congreso de la Asociación Española de Climatología celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022.[ES]El aumento extremo y prolongado de la temperatura del mar, una ola de calor marina (MHW), se detecta por comparación con los valores históricos en cada localización y época del año. Así, el correcto establecimiento de los valores de referencia es una tarea clave en la detección de MHW. Al comparar diferentes épocas es necesario considerar dos contribuciones a la evolución de los episodios extremos: la tendencia subyacente de la temperatura y los cambios súbitos de la misma. Siguiendo la definición de Hobday (2016), comparamos las MHW detectadas en caso de corregir o no la tendencia climatológica en la definición de los valores de referencia. Para ello empleamos 38 años de temperatura superficial del mar Mediterráneo proporcionados por el servicio Copernicus. El trabajo se centra alrededor de la reserva marina de las islas Columbretes, donde existe una estación costera de medición de la temperatura del mar integrada en la red T-MedNet. Esto permite vislumbrar el efecto a diferentes profundidades aunque con series temporales más cortas. El resultado es que no corregir la tendencia al definir la referencia subestima el número de eventos detectados en los primeros años de la serie y los sobreestima en los últimos, independientemente de la longitud de la serie. La influencia del cambio climático en la alteración de los ecosistemas marinos debido a las MHW no parece deberse al incremento en la frecuencia de las mismas, sino a que éstas tienen lugar en un mar cada vez más caliente, actuando sobre sistema biológicos con mayor estrés térmico.[EN]Extreme and prolonged increases in the sea temperature, a marine heatwave (MHW), are detected by comparison with historical values at each location and time of year. Thus, the correct estimation of reference values is key in detecting marine heatwaves. In temporally separated epochs comparison, it is necessary to consider two contributions to the evolution of extreme events: the underlying trend in temperature and its sudden changes. Following the definition of Hobday (2016), we compare the detected MHW in case of correcting or not the climatological trend in the definition of the reference values. We use 38 years of the surface temperature of the Mediterranean Sea provided by the Copernicus service. This work is centered around the Columbretes Islands marine reserve, where there is a coastal sea temperature measurement station integrated into the T-MedNet network. This allows us to have a glimpse of the effect at different depths but with shorter time series. The results show that if the long-term trend is not removed from the reference, then the number of events is underestimated in the first years of the series and overestimated in the last ones regardless of the length of the series. The influence of climate change on the alteration of marine ecosystems caused by the MHWs does not seem to be caused by the increased frequency of MHWs, but rather by the fact that the MHWs take place in an increasingly hot sea, acting on biological systems having greater thermal stress.This is a contribution made with the support of the MPA-Engage project (Grant:5216 | 5MED18_3.2_M23_007) and MINKE project (Grant: 101008724). The authors would like to thank the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)