Ion-exchange Equilibria Between Solid Aluminium Pectinates And Ca, Mnii, Cuii And Feiii Ions In Aqueous Solution

The ion-exchange equilibria between solid aluminium pectinates and aqueous solutions of calcium, manganese, zinc, copper and iron(III) nitrates have been studied at 298 K. The equilibria are generically represented by the equation: (z - i) Al(OH)2P(s) + M(OH)I (z-i)+(aq) ⇌ M(OH)iP(z-i)(s) + (z-i)Al(OH)2 +(aq) where P is the active site of pectinates containing (z-i) carboxy groups and their molecular surroundings, and M(OH)I (z-1)+ represents Ca(OH)+, Mn(OH)+, Zn(OH)+, Cu(OH)+, Fe(OH)+ and Fe(OH)2+. The equilibrium constants were determined using pectins with different degrees of methylation of the carboxy groups. The results are discussed in terms of interactions occurring in the ionic exchange for each of the metallic nitrates. Together with data from the literature it is possible to establish the following order of preference in bonding with pectins: FeIII > Al > Cu > Pb > Cd > Zn > Ni > Co > Sr ≈ Ca ≈ Mn > Mg.8441065107

Hydrodynamics of cholinium chloride-based aqueous biphasic systems (ABS): a key study for their industrial implementation

Aqueous biphasic systems (ABS) have been widely studied for extraction and purification processes. Although they are considered biocompatible, amenable, and sustainable separation platforms, their application on an industrial scale remains impractical without proper scaling and integration into existing processes. To better understand the hydrodynamics of ABS formation, three cholinium chloride ([Ch]Cl)-based ABS composed of polypropylene glycol with a molecular weight of 400 g.mol−1 (PPG-400), tripotassium phosphate (K3PO4), and dipotassium hydrogen-phosphate (K2HPO4) were studied. The hydrodynamics of phase separation of ABS composed of PPG-400/[Ch]Cl, [Ch]Cl/K3PO4 and [Ch]Cl/K2HPO4 was studied by analysing the relationship between the mixing time (Tm) and the phase settling time (Ts), at 25 °C and 50 °C. The results showed that Ts is independent of Tm, which is very long for the polymer/salt systems (Ts > 6 h), while for salt/salt ABS, a very fast phase settling was observed (Ts < 150 s). The hydrodynamics of each salt/salt system was then correlated with the physicochemical properties of the coexisting phases and the nature of the phase-forming compounds. The increase in the salting-out effect of the inorganic salts, and the consequent larger differences between the compositions of the coexisting phases, improved the hydrodynamics of the [Ch]Cl-based ABS. With the increase of the tie-line lengths, the composition of the phases stabilized, resulting also in more stable physicochemical properties in each phase and constant Ts. The correlations obtained in this work allow the definition of the best operating region within the biphasic (liquid-liquid) region of [Ch]Cl/salt-based ABS as being the largest TLLs within the LLE region. The definition of these criteria and region of operation is crucial for the design and industrial implementation of these types of LLE processes using conventional mixer-settler units.publishe

Aqueous two-phase systems: Towards novel and more disruptive applications

Aqueous two-phase systems (ATPS) have been mainly proposed as powerful platforms for the separation and purification of high-value biomolecules. However, after more than seven decades of research, ATPS are still a major academic curiosity, without their wide acceptance and implementation by industry, leading to the question whether ATPS should be mainly considered in downstream bioprocessing. Recently, due to their versatility and expansion of the Biotechnology and Material Science fields, these systems have been investigated in novel applications, such as in cellular micropatterning and bioprinting, microencapsulation, to mimic cells conditions, among others. This perspective aims to be a reflection on the current status of ATPS as separation platforms, while overviewing their applications, strengths and limitations. Novel applications, advantages and bottlenecks of ATPS are further discussed, indicating some directions on their use to create innovative industrial processes and commercial products.publishe

Synthesis of phenylseleno sugars from epoxides and of α,β-unsaturated carbonyl derivatives for the study of their insecticidal activity

This work reports the synthesis of sugar epoxides and their derivatives obtained by reaction with the dianion of phenyl selenoacetic acid. Approaches to the introduction of α,β-unsaturated carbonyl units in pyranoid systems were investigated. Preparation of a protected D-glycero-hex-3-enepyranosid-2-ulose and of a D-erythro-hex-2-enono-1,5-lactone is described. Some of the synthesized compounds possess insecticidal activity against fruit flies, house flies, and white flies.Treaty of Windsor Programme, British Council, Ministério da Ciência e do Ensino Superiorinfo:eu-repo/semantics/publishedVersio

Capillary electrophoresis-mass spectrometry characterisation of secondary metabolites from the antihyperglycaemic plant Genista tenera

Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100 min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant’s secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G. tenera. Twenty-six different components are distinguished in an analysis time of only 10 min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting.BBSRC, University of York, Treaty of Windsor Anglo-Portuguese joint research programme, Thermo Electron, Analytical Chemistry Trust Fund, Royal Society of Chemistry Analytical Division, Engineering and Physical Sciences Research Council (EPSRC)info:eu-repo/semantics/publishedVersio

Delay time and tunneling transient phenomena

Analytic solutions to the time-dependent Schr\"odinger equation for cutoff wave initial conditions are used to investigate the time evolution of the transmitted probability density for tunneling. For a broad range of values of the potential barrier opacity $\alpha$, we find that the probability density exhibits two evolving structures. One refers to the propagation of a {\it forerunner} related to a {\it time domain resonance} [Phys. Rev. A {\bf 64}, 0121907 (2001)], while the other consists of a semiclassical propagating wavefront. We find a regime where the {\it forerunners} are absent, corresponding to positive {\it time delays}, and show that this regime is characterized by opacities $\alpha < \alpha_c$. The critical opacity $\alpha_c$ is derived from the analytical expression for the {\it delay time}, that reflects a link between transient effects in tunneling and the {\it delay time}Comment: To be published in Physical Review

The role of ionic vs. non-ionic excipients in APIs-based eutectic systems

Aiming to contribute to drug pre-formulation, new eutectic mixtures were developed. Thymol, coumarin, or quaternary ammonium chlorides as excipients, were combined with the active pharmaceutical ingredients (APIs) acetylsalicylic acid, acetaminophen, ibuprofen, ketoprofen, or lidocaine. Their solid-liquid equilibrium (SLE) binary phase diagrams were measured to study eventual phase separation between the compounds, preventing manufacturing problems, and to study the molecular interactions between the APIs and ionic or non-ionic excipients. The Conductor-like Screening Model for Real Solvents (COSMO-RS) capability to predict the SLE of mixtures containing non-ionic excipients was further evaluated. COSMO-RS gives a good quantitative description of the experimental SLE being a tool with great potential in the screening of eutectic systems containing APIs and non-ionic excipients. While thymol presents strong interactions with the APIs, and consequently negative deviations to thermodynamic ideality, systems containing coumarin follow a quasi-ideal behavior. Regarding the ionic excipients, both choline chloride and the tetraalkylammonium chlorides are unable to establish relevant interactions with the APIs, and no significant negative deviations to ideality are observed. The liquefaction of the APIs here studied is favored by using non-ionic excipients, such as thymol, due to the strong interactions it can establish with the APIs.This work was developed within the scope of the project CICECO Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, and CIMO-Mountain Research Center, UIDB/00690/2020, both financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. L.P.S. acknowledges FCT for her PhD grant (SFRH/BD/135976/2018).info:eu-repo/semantics/publishedVersio

Quantum-wave evolution in a step potential barrier

By using an exact solution to the time-dependent Schr\"{o}dinger equation with a point source initial condition, we investigate both the time and spatial dependence of quantum waves in a step potential barrier. We find that for a source with energy below the barrier height, and for distances larger than the penetration length, the probability density exhibits a {\it forerunner} associated with a non-tunneling process, which propagates in space at exactly the semiclassical group velocity. We show that the time of arrival of the maximum of the {\it forerunner} at a given fixed position inside the potential is exactly the traversal time, $\tau$. We also show that the spatial evolution of this transient pulse exhibits an invariant behavior under a rescaling process. This analytic property is used to characterize the evolution of the {\it forerunner}, and to analyze the role played by the time of arrival, $3^{-1/2}\tau$, found recently by Muga and B\"{u}ttiker [Phys. Rev. A {\bf 62}, 023808 (2000)].Comment: To be published in Phys. Rev. A (2002

Potentialities of the extraction technologies and use of bioactive compounds from winery by-products: a review from a circular bioeconomy perspective

Agro-industrial by-products and by-products from the wine industry (pomace, peels, leaves, stems, and seeds) represent a potential economic interest because they are usually relevant natural sources of bioactive compounds, which may present significant biological activities related to human health and well-being. This article aims to review wine and winery industry by-products as potential natural sources of antioxidant, antimicrobial, anti-inflammatory, antiaging, and anticancer compounds, as well as briefly highlighting the extraction methods used to obtain these bioactive compounds and explore their potential applications in the food, cosmetic, and packaging industries. Although there are some studies of wine industry by-products with different origins, this revision will be mainly focused on the Portuguese vineyard industry since it represents an import industrial sector as proof of the diversity of the bioactive compounds identified. Therefore, the recovery of these bioactive molecules that act as antioxidants and health-promoting agents may promote a variety of industries at the same time as the circular economy.info:eu-repo/semantics/publishedVersio

FGFR1 and PROKR2 rare variants found in patients with combined pituitary hormone deficiencies.

The genetic aetiology of congenital hypopituitarism (CH) is not entirely elucidated. FGFR1 and PROKR2 loss-of-function mutations are classically involved in hypogonadotrophic hypogonadism (HH), however, due to the clinical and genetic overlap of HH and CH; these genes may also be involved in the pathogenesis of CH. Using a candidate gene approach, we screened 156 Brazilian patients with combined pituitary hormone deficiencies (CPHD) for loss-of-function mutations in FGFR1 and PROKR2. We identified three FGFR1 variants (p.Arg448Trp, p.Ser107Leu and p.Pro772Ser) in four unrelated patients (two males) and two PROKR2 variants (p.Arg85Cys and p.Arg248Glu) in two unrelated female patients. Five of the six patients harbouring the variants had a first-degree relative that was an unaffected carrier of it. Results of functional studies indicated that the new FGFR1 variant p.Arg448Trp is a loss-of-function variant, while p.Ser107Leu and p.Pro772Ser present signalling activity similar to the wild-type form. Regarding PROKR2 variants, results from previous functional studies indicated that p.Arg85Cys moderately compromises receptor signalling through both MAPK and Ca(2) (+) pathways while p.Arg248Glu decreases calcium mobilization but has normal MAPK activity. The presence of loss-of-function variants of FGFR1 and PROKR2 in our patients with CPHD is indicative of an adjuvant and/or modifier effect of these rare variants on the phenotype. The presence of the same variants in unaffected relatives implies that they cannot solely cause the phenotype. Other associated genetic and/or environmental modifiers may play a role in the aetiology of this condition