Publications

Abstract Thymus capitatus is a Mediterranean endemic plant commonly known as Zaitra in northern Morocco. As T. capitatus is widely used in traditional medicine and food, this present work aims to investigate the chemical compositions and biological activities of the T. capitatus leaves essential oil (TcLEO), acetonic (TcLAE), and methanolic extract (TcLME). The spectrophotometric determination demonstrated that T. capitatus is a natural source rich in phenolic contents (TPC) and flavonoid contents (TFC) and that TcLME revealed the highest TPC and TFC than TcLAE and TcLEO. The LC-MS analysis of phenolic compounds showed that paraben acid was predominant in both TcLME and TcLAE, followed by cinnamic acid and p-hydroxybenzoic acid. GC-MS analysis of the TcLEO revealed the presence of a total of 10 compounds, which were predominated by carvacrol. The antioxidant activity by ORAC was observed to be significantly higher in TcLEO and TcLAE than in TcLME. All samples used to assess DNA degradation effectively prevented DNA oxidation and, at the same time, had a prooxidant effect. The genotoxicity test showed that the T. capitatus were devoid of any mutagenic activity. Concerning antifungal activity, all samples were able to inhibit the growth of all microorganisms tested at low concentrations. TcLAE showed higher activity than TcLME, and in general, dermatophytes were more susceptible, being Microsporum canis the most sensitive one. Overall, the results obtained from this study confirm the wide uses of T. capitatus. Furthermore, the finding results suggest that the T. capitatus essential oil and extracts can be highly useful for pharmaceutical industries.

Abstract Over the years, literature reported inumerous applications of electrochemical and surface plasmon resonance (SPR) immunoassays for biosensing but, so far, the combination of the two methods in the same sensing spot for analytical purposes is much less explored and discussed. The aim of this Review is to highlight the great potential of electrochemistry combined-SPR (eSPR) as analytical tool for screening chemically and biologically relevant (bio)molecules by combining the unique features of SPR integrated with electrochemical readout.In the first part of the Review, we describe the urgent need of innovative methods for screening clinical biological markers (General Introduction), briefly discuss general concepts of SPR and electrochemical sensing (Concepts behind eSPR biosensors) and highlight the hyphenation of two methods to developed combined biosensing systems (Set-up configuration and eSPR principles). Firstly, we briefly give an overview of the setup for implementation of eSPR technique and discuss some relevant experimental conditions to perform the combined optical and electrochemical measurements. Then, the principles and fundamentals of eSPR biosensors are presented and described. We also present representative examples of eSPR biosensors in the literature (Applications of eSPR biosensors).In the second part, we review studies on how combined electrical and plasmonic detection contributed to the biosensing field, in particular, for the successful screening of clinically relevant biomolecules, namely proteins (Detection of proteins), nucleic acids (Detection of nucleic acids), small size chemical species (Detection of small molecules) and cells (Living-cell Analysis).Finally, we discuss the current limitations of eSPR biosensors performance and suggest possible ways to overcome these limitations (Limitations and optimization) and then we explore aspects about the development of the method and its applications and discuss areas of likely future growth (Conclusions and perspectives). (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82-) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 degrees C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82-, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min(-1) and UV/1.02 mM S2O82-/TIP-CD-0.0345 min(-1).

Abstract A system of dimethyl ester of 3,3 ''''-bisdecyl[2,2 ':5 ',2 '':5 '',2 ''':5 ''',2 '''':5 '''',2 ''''']sexithiophene-5,5 '''''-dicarboxylic acid, with polyethylene oxide, copolymer (ST) and [6,6]phenyl-C61-butyric acid methyl ester (PCBM) is of photochemical interest. A focus is on dynamics within the ST/PCBM donor/acceptor system as a solution and as a film by means of fluorescence spectroscopy, cyclic voltammetry, and atomic force microscopy. ST forms intra-molecular rod-coil aggregates in the solution and terraces of aggregates in the film. ST/PCBM fluorescence spectra from the solution:film result in a spectral red shift of 60 nm and intensity decrease with a ratio of 17:8, respectively. The fluorescence decay times tau(1) increase with increasing PCBM concentration from 17.0 to 25.5 ps and from 5.8 to 19 ps in the solutions and the films, respectively. Interestingly, the decay time tau(2) result for the solutions and for the films to be on average 491 ps and 78 ps, describing the slower and the faster overall process, respectively. HOMO/LUMO levels for ST and PCBM are - 7.27 eV/- 4.42 eV and - 6.68 eV/- 4.43 eV, respectively. Excitation energy transfer between ST and PCBM is observed as radiative quenching and static quenching through the disaggregation of the ST aggregates by PCBM molecules.

Abstract The intramolecular chemiexcitation of high-energy peroxide intermediates, such as dioxetanones, is an essential step in different chemi- and bioluminescent reactions. Here, we employed the Time-Dependent Density Functional Theory (TD-DFT) methodology to evaluate if and how external stimuli tune the intramolecular chemiexcitation of model dioxetanones. More specifically, we evaluated whether the strategic placement of ionic species near a neutral dioxetanone model could tune its thermolysis and chemiexcitation profile. We found that these ionic species allow for the dark catalysis of the thermolysis reaction by reducing the activation barrier to values low enough to be compatible with efficient chemi- and bioluminescent reactions. Furthermore, while the inclusion of these species negatively affected the chemiexcitation profile compared with neutral dioxetanones, these profiles appear to be at least as efficient as anionic dioxetanones. Thus, our results demonstrated that the intramolecular chemiexcitation of neutral dioxetanones can be tuned by external stimuli in such a way that their activation barriers are decreased. Thus, these results could help to reconcile findings that neutral dioxetanones could be responsible for efficient chemi-/bioluminescence, while being typically associated with high activation parameters.

Abstract This paper examines the determinants of FDI in small states, as only a small number of studies have analyzed the determinants of FDI in these countries. Small states have particular features that justify the need for a deeper analysis. Based on a panel data for 42 small states between 2005 and 2019, results clearly indicate the importance of the quality of human capital and the availability of infrastructures as the strongest drivers of FDI in small states. The country's level of openness, the availability of natural resources, the level of corporate tax and control of corruption also seems to play a relevant role therein. Moreover, the results suggest that the determinants differ depending on the region to which the country belongs and differ between island and non-island countries. These results can help small countries in defining policies that help them to attract FDI, which is crucial for their sustainable development.

Abstract Diclofenac (DCF) is a very common pharmaceutical that, due to its high use and low removal rate, is considered a prominent contaminant in surface and groundwater worldwide. In this study, Solanum lycopersicum L. cv. MicroTom (tomato) was used to disclose the role of glutathione (GSH)-related enzymes, as GSH conjugation with DCF is a well reported detoxification mechanism in mammals and some plant species. To achieve this, S. lycopersicum plants were exposed to 0.5 and 5 mg L-1 of DCF for 5 weeks under a semi-hydroponic experiment. The results here obtained point towards an efficient DCF detoxification mechanism that prevents DCF bioaccumulation in fruits, minimizing any concerns for human health. Although a systemic response seems to be present in response to DCF, the current data also shows that its detoxification is mostly a root-specific process. Furthermore, it appears that GSH-mediated DCF detoxification is the main mechanism activated, as glutathione-S-transferase (GST) activity was greatly enhanced in roots of tomato plants treated with 5 mgL(-1) DCF, accompanied by increased glutathione reductase activity, responsible for GSH regeneration. By applying a targeted gene expression analysis, we provide evidence, for the first time, that SlGSTF4 and SlGSTF5 genes, coding for GSTs from phi class, were the main players driving the conjugation of this contaminant. In this sense, and even though tomato plants appear to be somewhat tolerant to DCF exposure, research on GST activity can prove to be instrumental in remediating DCF-contaminated environments and improving plant growth under such conditions.

Abstract Photocatalysis has received special attention from researchers that focus on evaluating its potential applications in the fields of energy, environment, and therapeutics, in an economically sustainable way. The photocatalysts that are most often discussed in literature are the ones composed of semiconductors, such as TiO2, ZnO, CdS, ZnS, CeO2 and WO3, since they possess an exquisite combination of optical, physical and chemical properties. Among these semiconductors, TiO2 has been amply studied due to its high refraction index, bandgap of 3.0-3.2 eV, high chemical and photostability, low cost and high range of potential applications. Within this scope, the obtainment of hollow spherical structures of micro- and nanometer size has been heavily motivated by an array of advantages such as high surface area, low density, high charge capacity, high shell permeability, amongst others. When compared to their bulk counterparts, literature data indicates a significant increase in photonic efficiency by using hollow spheres, mostly due to multiple processes of diffraction and reflection of light. Moreover, selectivity is an important feature of photocatalysts, that also enhances photonic efficiency. It may be expressed in two different manners. The first one concerns with selective photocatalysts to the substrate, which focus on the required surficial phenomena of adsorption of a target molecule by the photocatalyst before the catalysis reaction can take place. The second one concerns the selective photocatalysts to the desired product. In this review, the developments accomplished in recent years (mostly 2018 onwards) are addressed, encompassing a quite productive period, both regarding selectivity, hollowness and their synergisms. Product selectivity has been relying mainly on the utilization of metallic dopants, mostly noble metals. However, doping with non-metallic elements (N, F, P) and pairs of metallic elements, such as Pd/Cu and Au/Ag, appears to be gaining an increased acceptance. New insights into the mechanisms of selectivity by doping, besides the usual consideration of the reduction of band gap, were produced. A great vitality could also be found in the usage of cocatalysts (metal, metal/polymer, graphene). Concerning substrate selectivity, morphology and surface structuring have been the approaches of choice since a long time already. A recent trend was also identified, namely that of seeking synergisms between increasing photonic efficiency and increasing selective capacity, although this has presented itself as a challenge. An additional trend recently observed was that of attempting a simultaneous substrate and product selectivity, in order to make the photocatalytic process even more effective. In the case of hollow TiO2, this review addresses the control of crystallinity of the shell which is frequently under the risk of bursting due to the harsh conditions applied. To circumvent the possibility of bursting, two main strategies have been proposed, "silica-protected calcination" and "acid pretreatment". Finally, the combination of hollowness and selectivity has captured the attention of researchers. Molecular imprinting took the lead when it came to structuring the hollow shell, mostly via the post-calcination deposition of an imprinted polymer. To introduce product selectivity, modifications both of the outer and of the inner surface of the shell were reported. The possibility of tuning the properties of the outer and inner surfaces separately, opens new creative avenues in the field of TiO2-supported photocatalysis, with subsequent modification of reaction mechanisms.

Abstract <jats:p>This work introduces a method specially developed to produce a biorecognition element based on modified Stöber silica nanoparticles by the covalent immobilization of the human IgG. The sensing structure is based on long period fiber gratings (LPFG), specially developed to allow the interaction of the electromagnetic wave with the target analytes through its evanescent field. The surface was modified by the immobilization of the IgG-modified nanoparticles serving has recognition elements for specific target molecules. The resulting configuration was tested in the presence of anti-human IgG, recording the refractometric response of the modified LPFG in contact with different amounts of analyte. The selectivity of the sensor was also assessed.</jats:p>