In this work, a procedure was elaborated to quantify hydrogen peroxide (H
2
O
2
) after degradation tests of dyes present in a synthetic textile matrix. For this purpose, based on the intensity of ...radiation absorption of the peroxovanadium cation, which was formed by the reaction between the oxidant and vanadate ions, ultraviolet/visible spectrophotometry technique was used. The most suitable experimental condition was composed of concentrations of 0.05 mol L
−1
(NH
4
VO
3
) and 0.3 mol L
−1
(H
2
SO
4
). The system for dye treatment involved the photo-Fenton process under simulated sunlight. In this case, concentrations of 900 mg L
−1
(H
2
O
2
) and 4 mg L
−1
(iron) in pH 3 were the most efficient for degrading contaminants. An efficiency of 94.49% was obtained after 180 min of reaction, the time in which the presence of the oxidant was no longer verified. The kinetic monitoring showed a two-stage degradation, described with accuracy greater than 96% by the linear and non-linear kinetic models of pseudo-first order. Additionally, the degradation under natural solar radiation was also studied, which resulted in an efficiency of 92.45% after 360 min and in the presence of the residual oxidant. Finally, via mathematical modeling and employing a Multilayer Perceptron neural network, with a 3-10-2 topology and BFGS 387 training algorithm, it was possible to predict the degradation and H
2
O
2
residual concentration with an accuracy greater than 98%. Therefore, the degradation study developed and the proposed methodology for determining residual H
2
O
2
proved to be adequate and capable of contributing positively to related research.
Graphic abstract
Environmental stress is a fundamental facet of life and a significant driver of natural selection in the wild. Gene expression diversity may facilitate adaptation to environmental changes, without ...necessary genetic change, but its role in adaptive divergence remains largely understudied in Neotropical systems. In Amazonian riparian forests, species distribution is predominantly influenced by species' waterlogging tolerance. The flooding gradient delineates distinct wetland forest types, shaping habitats and species characteristics. Here we investigated the molecular basis of environmental stress response in a tropical ground-herb species (Ischnosiphon puberulus) to environmental variation in Amazonian riparian forests. We compared environmental variables and gene expression profiles from individuals collected in two forest types: Igapó and Terra firme in the Amazonian riparian forests. Predictable seasonal flooding poses a significant challenge in Igapó compared to Terra firme environments, with the former presenting higher water column height and longer flooding duration. Our findings suggest that contrasting environmental conditions related to flooding regimes are important drivers of population genetic differentiation and differential gene expression in I. puberulus. Enriched gene ontology terms highlight associations with environmental stresses, such as defence response, water transport, phosphorylation, root development, response to auxin, salicylic acid and oxidative stress. By uncovering key environmental stress response pathways conserved across populations, I. puberulus offers novel genetic insights into the molecular basis of plant reactions to environmental constraints found in flooded areas of this highly biodiverse neotropical ecosystem.Environmental stress is a fundamental facet of life and a significant driver of natural selection in the wild. Gene expression diversity may facilitate adaptation to environmental changes, without necessary genetic change, but its role in adaptive divergence remains largely understudied in Neotropical systems. In Amazonian riparian forests, species distribution is predominantly influenced by species' waterlogging tolerance. The flooding gradient delineates distinct wetland forest types, shaping habitats and species characteristics. Here we investigated the molecular basis of environmental stress response in a tropical ground-herb species (Ischnosiphon puberulus) to environmental variation in Amazonian riparian forests. We compared environmental variables and gene expression profiles from individuals collected in two forest types: Igapó and Terra firme in the Amazonian riparian forests. Predictable seasonal flooding poses a significant challenge in Igapó compared to Terra firme environments, with the former presenting higher water column height and longer flooding duration. Our findings suggest that contrasting environmental conditions related to flooding regimes are important drivers of population genetic differentiation and differential gene expression in I. puberulus. Enriched gene ontology terms highlight associations with environmental stresses, such as defence response, water transport, phosphorylation, root development, response to auxin, salicylic acid and oxidative stress. By uncovering key environmental stress response pathways conserved across populations, I. puberulus offers novel genetic insights into the molecular basis of plant reactions to environmental constraints found in flooded areas of this highly biodiverse neotropical ecosystem.
The problems of resistance and side effects associated with cisplatin and other chemotherapeutic drugs have boosted research aimed at finding new compounds with improved properties. The use of ...platinum(IV) prodrugs is one alternative, although there is some controversy regarding the predictive ability of the peak reduction potentials. In the work described here a series of fourteen chloride Pt(II) and Pt(IV) compounds was synthesised and fully characterised. The compounds contain different bidentate arylazole heterocyclic ligands. Their cytotoxic properties against human lung carcinoma (A549), human breast carcinoma (MCF7) and human colon carcinoma (HCT116 and HT29) cell lines were studied. A clear relationship between the type of ligand and the anti-proliferative properties was found, with the best results obtained for the Pt(II) compound that contains an aniline fragment, (13), thus evidencing a positive effect of the NH2 group. Stability and aquation studies in DMSO, DMF and DMSO/water mixtures were carried out on the active complexes and an in-depth analysis of the two aquation processes, including DFT analysis, of 13 was undertaken. It was verified that DNA was the target and that cell death occurred by apoptosis in the case of 13. Furthermore, the cytotoxic derivatives did not exhibit haemolytic activity. The reduction of the Pt(IV) compounds whose Pt(II) congeners were active was studied by several techniques. It was concluded that the peak reduction potential was not useful to predict the ability for reduction. However, a correlation between the cytotoxic activity and the standard reduction potential was found.
Synopsis for Graphical Abstract
The cytotoxicity against different cancer cell lines of Pt(II) and Pt(IV) compounds containing heterocyclic ligands was studied with the best results obtained when a aniline fragment was present. DNA was the target. For the Pt(IV) compounds, the standard reduction potential was a more reliable parameter than the peak reduction potential. Display omitted
•Standard reduction potential as predicting tool for Pt(IV) prodrugs.•A chloride Pt(II) complex with an aniline fragment very cytotoxic.•Study of two aquation processes by DFT analysis.
In the treatment of hormone-dependent cancers, aromatase inhibitors (AI) are receiving increased attention due to some undesirable effects such as the risk of endometrial cancer and thromboembolism ...of SERMs (selective estrogen receptor modulators). Letrozole is the most active AI with 99% aromatase inhibition. Unfortunately, this compound also exhibits some adverse effects such as hot flashes and fibromyalgias. Therefore, there is an urgent need to explore new types of AIs that retain the same—or even increased—antitumor ability. Inspired by the letrozole structure, a set of new derivatives has been synthesized that include a ferrocenyl moiety and different heterocycles. The derivative that contains a benzimidazole ring, namely compound
6
, exhibits a higher aromatase inhibitory activity than letrozole and it also shows potent cytostatic behavior when compared to other well-established aromatase inhibitors, as demonstrated by dose–response, cell cycle, apoptosis and time course experiments. Furthermore,
6
promotes the inhibition of cell growth in both an aromatase-dependent and -independent fashion, as indicated by the study of A549 and MCF7 cell lines. Molecular docking and molecular dynamics calculations on the interaction of
6
or letrozole with the aromatase binding site revealed that the ferrocene moiety increases the van der Waals and hydrophobic interactions, thus resulting in an increase in binding affinity. Furthermore, the iron atom of the ferrocene fragment can form a metal-acceptor interaction with a propionate fragment, and this results in a stronger coupling with the heme group—a possibility that is consistent with the strong aromatase inhibition of
6
.
Graphical abstract
Aquatic insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) have a wide distribution and play an important ecological role in aquatic ecosystems, primarily in nutrient cycling in ...lotic systems. They also exhibit high morphological and functional diversity. Although there are numerous studies evaluating the morphological and functional diversity of EPT, this knowledge is fragmented and dispersed in the literature. It is important to synthesize this information, especially in regions with high diversity like, the Amazon. This synthesis of morphological, ecological, and life history traits of EPT genera occurring in the Amazon can contribute to advancing our understanding of the functioning of freshwater ecosystems in the region and the management of their watersheds. The objective of this study was to compile information into a database of functional traits of EPT immatures stage with documented distribution in the Brazilian Amazon. The database of this study recorded information on eight morphological, ecological, and life history traits of 95 EPT genera. We also identified knowledge gaps of these traits for genera with few occurrence records (rarer records). The information from the EPT traits database can be used to address fundamental research questions in ecology regarding the functioning of freshwater ecosystems.
Los autores presentan una nueva lectura de las inscripciones del ataúd de Esoeris, hija de Nespamay, junto con una breve descripción del mismo y una discusión respecto de las citadas inscripciones. ...La intención principal del artículo es ofrecer una transcripción del nombre de la madre de Esoeris, corrigiendo los datos prosopográficos que brinda el ataúd.
In this paper, we propose to explain Middle Persian rōzag ‘fasting’ as a decompositional formation from dō-rōz=ag ‘(fasting ritual) of two days’. It is neither possible – we argue – to explain rōzag ...as a formation with the sufffix*-(a)ka- from the primary word rōz ‘day’ nor °rōzag-compounds as compounds with rōzag ‘fasting’ as a second member. We discuss °rōzag-compounds generally. We postulate, for instance, that Parthian bēmrōzag does not mean ‘fasting day of the Bema’ but ‘commemoration of the Bema’. At the end, we put up for discussion that there may be other suchlike decompositional words in Iranian languages, for instance paT zanag ‘kind’. Key Biblical quotations are identified in M 2 (Mk 9.29) and M 16 supporting our translations.
(At the end of this article, there is a list of the formations, words and passages that we discuss.)
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Gamma variant of concern has spread rapidly across Brazil since late 2020, causing substantial infection and death waves. Here we used ...individual-level patient records after hospitalization with suspected or confirmed coronavirus disease 2019 (COVID-19) between 20 January 2020 and 26 July 2021 to document temporary, sweeping shocks in hospital fatality rates that followed the spread of Gamma across 14 state capitals, during which typically more than half of hospitalized patients aged 70 years and older died. We show that such extensive shocks in COVID-19 in-hospital fatality rates also existed before the detection of Gamma. Using a Bayesian fatality rate model, we found that the geographic and temporal fluctuations in Brazil's COVID-19 in-hospital fatality rates were primarily associated with geographic inequities and shortages in healthcare capacity. We estimate that approximately half of the COVID-19 deaths in hospitals in the 14 cities could have been avoided without pre-pandemic geographic inequities and without pandemic healthcare pressure. Our results suggest that investments in healthcare resources, healthcare optimization and pandemic preparedness are critical to minimize population-wide mortality and morbidity caused by highly transmissible and deadly pathogens such as SARS-CoV-2, especially in low- and middle-income countries.
Currently, cancer is one of the most serious problems facing humanity, and one of the most widely used and versatile diagnostic techniques is magnetic resonance imaging (MRI), which may require an ...injection of contrast agents (CAs). CAs are paramagnetic compounds capable of increasing the relaxation rate of water protons, thereby obtaining clearer MRI examination images. In this work, the solvent and thermal effects on spectroscopic parameters of Fe(H
2
O)
6
2+
, Mn(H
2
O)
6
2+
, Gd(H
2
O)
8
3+
, and γ-Fe
2
O
3
, coordinated to explicit water molecules, were studied in light of the classical and quantum methods. For the classical part of the simulation, a new method of selection of configurations from the molecular dynamics simulations, denominated optimal wavelet signal compression algorithm (OWSCA), is presented. Our findings indicate that OWSCA leads to a good agreement with the experimental available data and the thermal effects greatly influence our system. Thus, the molecular dynamics calculations are important for this type of system. Our results show the γ-Fe
2
O
3
as a promising alternative to conventional contrast agents.
Display omitted
The human tissue kallikreins (KLK1–KLK15) comprise a family of 15 serine peptidases detected in almost every tissue of the human body and that actively participate in many ...physiological and pathological events. Some kallikreins are involved in diseases for which no effective therapy is available, as for example, epithelial disorders, bacterial infections and in certain cancers metastatic processes. In recent years our group have made efforts to find inhibitors for all kallikreins, based on natural products and synthetic molecules, and all the inhibitors developed by our group presented a competitive mechanism of inhibition. Here we describe fukugetin, a natural product that presents a mixed-type mechanism of inhibition against KLK1 and KLK2. This type of inhibitor is gaining importance today, especially for the development of exosite-type inhibitors, which present potential to selectively inhibit the enzyme activity only against specific substrate.
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