Synthesis of chromone-related pyrazole compounds

Chromones, six-membered oxygen heterocycles, and pyrazoles, five-membered two-adjacent-nitrogen-containing heterocycles, represent two important classes of biologically active compounds. Certain derivatives of these scaffolds play an important role in medicinal chemistry and have been extensively used as versatile building blocks in organic synthesis. In this context, we will discuss the most relevant advances on the chemistry that involves both chromone and pyrazole rings. The methods reviewed include the synthesis of chromone-pyrazole dyads, synthesis of chromone-pyrazole-fused compounds, and chromones as starting materials in the synthesis of 3(5)-(2-hydroxyaryl)pyrazoles, among others. This review will cover the literature on the chromone and pyrazole dual chemistry and their outcomes in the 21st century.Thanks are due to University of Aveiro and FCT/MEC for the financial support of the QOPNA research unit (FCT UID/QUI/00062/2013) and CIQ-UP, University of Porto (POCI-01-0145-FEDER-006980; FCT: UID/QUI/00081/2013) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement, as well as to the Polytechnic Institute of Bragança. V.L.M.S. is grateful to FCT for her grant (SFRH/BPD/108807/2015), in the ambit of “QREN e POCH e Tipologia 4.1 e Formação Avançada”, co-sponsored by FSE and by national funds of MCTES.info:eu-repo/semantics/publishedVersio

Arylxanthones and arylacridones: a synthetic overview

Arylxanthones and arylacridones although not yet found in nature are becoming an important group of heterocyclic compounds due to their promising biological activities. Their central cores, xanthone and acridone, are recognized as interesting motifs for drug development mainly to be used in antitumour chemotherapy. The synthesis of this type of compounds is still scarce but several successful examples were recently published and a large variety of arylated xanthone and acridone derivatives were prepared. A systematic survey of the literature dedicated to their synthesis will be presented and discussed in this review.Thanks are due to the University of Aveiro, Polytechnic Institute of Bragança, Fundação para a Ciência e a Tecnologia (FCT) FCT/MEC for the financial support of the QOPNA research Unit (FCT UID/QUI/00062/2013) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement. V.L.M. Silva also acknowledges FCT for the financial support of her post-doctoral grant (SFRH/BPD/108807/2015), in the ambit of “QREN e POCH e Tipologia 4.1 e Formação Avançada”, co-sponsored by FSE and by national funds of MCTESinfo:eu-repo/semantics/publishedVersio

Quantification of Iron in Seawater at the Low Picomolar Range Based on Optimization of Bromate/Ammonia/Dihydroxynaphtalene System by Catalytic Adsorptive Cathodic Stripping Voltammetry

A new analytical protocol for the challenging analysis of total dissolved iron at the low picomolar level in oceanic waters suitable for onboard analysis is presented. The method is based on the revision of the adsorptive properties of the iron/2,3-dihydroxynaphthalene (Fe/DHN) complexes on the hanging mercury drop electrode with catalytic enhancement by bromate ions. Although it was based on a previously proposed reagent combination, we show here that the addition of an acidification/alkalinization step is essential in order to cancel any organic complexation, and that an extra increment of the pH to 8.6-8.8 leads to the definition of a preconcentration-free procedure with the lowest detection limit described up to now. For total dissolved iron analysis, samples were acidified to pH 2.0 in the presence of 30 \u3bcM DHN and left to equilibrate overnight. A 10 mL sample was subsequently buffered to a pH of 3c8.7 in the presence of 20 mM bromate: a 60 s deposition at 0 V led to a sensitivity of 34 nA nM-1 min-1, a 4-fold improvement over previous methods, that translated in a limit of detection of 5 pM (2-20 fold improvement). Several tests proved that a nonreversible reaction in the time scale of the analysis, triggered by the acidification/alkalinization step, was behind the signal magnification. The new method was validated onboard via the analysis of reference material and via intercalibration against flow injection analysis-chemiluminescence on Southern Ocean surface samples

Preliminary study on the potential use of RPA images to quantify the influence of the defoliation after coffee harvesting to its yield

Received: January 24th, 2023 ; Accepted: May 22nd, 2023 ; Published: September 18th, 2023 ; Correspondence: [email protected] is an agricultural commodity with global commercial importance capable of impacting the production chain. The quantification of defoliation at harvest is important for monitoring crop yield because defoliation is one of the main types of damage caused by this agricultural operation in coffee crops. Thus, the objective of this study was to evaluate the relationship between yield and defoliation obtained in the field and obtained through remotely piloted aircraft (RPA) images. The experiment was conducted in a coffee plantation belonging to the Federal University of Lavras (UFLA), Lavras, Minas Gerais state, Brazil. An RPA with a rotary wing containing a multispectral camera was used in autonomous flight mode with a height of 30 m, an image overlap of 80%, and a speed of 3 m s-1 . The images were collected before and after the 2020 and 2021 harvest, defoliation data obtained in the field were measured in 2020 and 2021, and the yield was measured from 2019 to 2021. Image processing was performed in the software PhotoScan, postimage processing was performed in QGIS, and statistical analyses were performed using the software R. With the processing of the images in 2020, the crop showed reductions of 17.3% and 18.4% in leaf area and volume, respectively, after harvest. In 2021, the crop showed reductions of 12.8% and 9.8% in leaf area and volume, respectively, after harvest. The leaf area and leaf volume of the coffee plantation after harvest could be quantified by means of images obtained by RPA, which allowed the observation of the loss of area and volume of the coffee plantation. Furthermore, it was possible to analyse the interactions between field data and the yield of the same harvest year, which were directly proportional, and the interaction of image data from one year with the previous yield, which were inversely proportional. In the year 2020, there was a reduction of 17.3% in leaf area after harvest, and a reduction of 18.4% in leaf volume after harvest in the plots under study.In the processing carried out in 2021, there was a 12.8% reduction in leaf area after harvest, and a 9.8% decrease in leaf volume after harvest in the plots under study

Magnetic And Magnetocaloric Properties On The U1-y Ry Ga2 (r=er And Dy) Compound

The magnetic, calorimetric, and magnetocaloric properties of the pseudobinary U1-y Ry Ga2 (R=Er and Dy) series were studied to determine its potential as a candidate for use in cryogenic magnetic refrigeration. The partial substitution of Dy and Er for U provides a wide range of the ordering temperature and increases the saturation magnetic moment. The results for U1-y Dyy Ga2 with 0.6<y<0.9 show evidences of a spin-glass-like (SG) behavior, possibly as a consequence of competing anisotropy and exchange interactions within a frustrated hexagonal spin lattice. The isothermal magnetic entropy change (Δ Smag) observed for U Ga2 shows a well defined peak centered on TC, which is gradually broadened and shifted to lower temperatures as the Er and Dy content increases. For low concentrations (0.2≤y≤0.4) a tablelike profile is observed in the Δ Smag curve. © 2008 American Institute of Physics.1037Gschneidner Jr., K.A., Pecharsky, V.K., Tsokol, A.O., (2005) Radiat. Prot. Dosim., 68, p. 1479Bruck, E., (2005) J. Phys. D, 38, p. 381Yu, B.F., Gao, Q., Zhang, B., Meng, X.Z., Chen, Z., (2003) Int. J. Refrig., 26, p. 622Gschneidner Jr., K.A., Pecharsky, A.O., Pecharsky, V.K., (2001), 11, p. 433. , Cryoolers (Academic-Plenum, New York), Vol.,Smaili, A., Chahine, R., (1996) Adv. Cryog. Eng., 42, p. 445Hashimoto, T., Kuzuhura, T., Sahashi, M., Inomata, K., Tomokiyo, A., Yayama, H., (1987) J. Appl. Phys., 62, p. 3873Lima, A.L., Gschneidner Jr., K.A., Pecharsky, V.K., Pecharsky, A.O., (2003) Phys. Rev. B, 68, p. 134409De Oliveira, N.A., Von Ranke, P.J., (2003) J. Magn. Magn. Mater., 264, p. 55Tsai, T.H., Sellmyer, D.J., (1979) Phys. Rev. B, 20, p. 4577Doukouŕ, M., Gignoux, D., (1982) J. Magn. Magn. Mater., 30, p. 111Gignoux, D., Schimitt, D., Takeuchi, A., Zhang, F.Y., (1991) J. Magn. Magn. Mater., 97, p. 15Andreev, A.V., Belov, K.P., Deryagin, A.V., Levitin, R.Z., Menovsky, M., (1979) J. Phys. Colloq., 4, p. 82Mydosh, J.A., (1993), Spin Glasses: An Experimental Introduction (Taylor&Francis, London)Markin, P.E., Baranov, N.V., Sinitsyn, E.V., (1991) Physica B, 168, p. 19

Striatal and extrastriatal atrophy in Huntington's disease and its relationship with length of the CAG repeat

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that affects the striatum most severely. However, except for juvenile forms, relative preservation of the cerebellum has been reported. The objective of the present study was to perform MRI measurements of caudate, putamen, cerebral, and cerebellar volumes and correlate these findings with the length of the CAG repeat and clinical parameters. We evaluated 50 consecutive patients with HD using MRI volumetric measurements and compared them to normal controls. Age at onset of the disease ranged from 4 to 73 years (mean: 43.1 years). The length of the CAG repeat ranged from 40 to 69 (mean: 47.2 CAG). HD patients presented marked atrophy of the caudate and putamen, as well as reduced cerebellar and cerebral volumes. There was a significant correlation between age at onset of HD and length of the CAG repeat, as well as clinical disability and age at onset. The degree of basal ganglia atrophy correlated with the length of the CAG repeat. There was no correlation between cerebellar or cerebral volume and length of the CAG repeat. However, there was a tendency to a positive correlation between duration of disease and cerebellar atrophy. While there was a negative correlation of length of the CAG repeat with age at disease onset and with striatal degeneration, its influence on extrastriatal atrophy, including the cerebellum, was not clear. Extrastriatal atrophy occurs later in HD and may be related to disease duration.1129113

Texture analysis of computed tomography images of acute ischemic stroke patients

Computed tomography (CT) images are routinely used to assess ischemic brain stroke in the acute phase. They can provide important clues about whether to treat the patient by thrombolysis with tissue plasminogen activator. However, in the acute phase, the lesions may be difficult to detect in the images using standard visual analysis. The objective of the present study was to determine if texture analysis techniques applied to CT images of stroke patients could differentiate between normal tissue and affected areas that usually go unperceived under visual analysis. We performed a pilot study in which texture analysis, based on the gray level co-occurrence matrix, was applied to the CT brain images of 5 patients and of 5 control subjects and the results were compared by discriminant analysis. Thirteen regions of interest, regarding areas that may be potentially affected by ischemic stroke, were selected for calculation of texture parameters. All regions of interest for all subjects were classified as lesional or non-lesional tissue by an expert neuroradiologist. Visual assessment of the discriminant analysis graphs showed differences in the values of texture parameters between patients and controls, and also between texture parameters for lesional and non-lesional tissue of the patients. This suggests that texture analysis can indeed be a useful tool to help neurologists in the early assessment of ischemic stroke and quantification of the extent of the affected areas.1076107

Nutrição De Tithonia Diversifolia E Atributos Do Solo Adubado Com Biofertilizante Em Sistema Irrigado

The fertilization with biofertilizer associated with the use of irrigation favors nutrient uptake by plants and soil chemical properties; however, these effects are little studied in Tithonia diversifolia in semiarid regions. This study evaluated the effect of doses of bovine biofertilizer and irrigation on accumulation of nutrients in the leaves of Tithonia diversifolia plants and on soil chemical attributes. The study was carried out from December 3, 2014 to November 28, 2015, and arranged in a 2 x 5 factorial scheme, consisting of five doses of bovine biofertilizer (0, 40, 80, 120 and 160 m3 ha-1), combined with and without irrigation. The experiment was set in a randomized block design, using three replicates. Irrigation promoted increased accumulation of N, P, K, Ca, Mg, S, Zn, Fe, Mn, Cu and B in leaves of Tithonia diversifolia in the first cutting. However, the high bicarbonate concentration in the irrigation water and the occurrence of rainfall during the second crop increased the accumulation of Cu in the leaves of Tithonia diversifolia under rainfed condition, compared with irrigated plants. The increase in biofertilizer doses contributed to the increment of base saturation and the contents of organic matter, P and K in soil. © 2016, Departamento de Engenharia Agricola - UFCG/Cnpq. All rights reserved.20111008101

Produtividade Da Crotalaria Juncea Sob Podas E Densidades De Semeadura Nos Tabuleiros Costeiros Do Piauí

The northern region of Piauí state is an important center of irrigated organic fruit farming, wherein sandy soils with low organic matter content are predominant, besides climate with high temperatures, long periods of water deficit and constant wind. Given this situation, it becomes necessary to investigate alternative management options able to meet the challenges of agricultural productivity. In this context, green manuring becomes an important practice, mainly when using fast-growing species and with great potential for biomass production. Thus, a study was carried out at Embrapa Meio-Norte to measure Crotalaria juncea biomass yield after thinning and at various sowing densities. The evaluated parameters were plant height, stem diameter, number of branches per plant, fresh and dry weight of shoots and roots. The results showed that sowing density had no influence on plant height; however, unthinned plants reached greater heights, which might have been due to reduced competition for light. Thinning had no effect on diameters of plant stem base; on the other hand, lower planting densities promoted larger diameters also due to less competition. Likewise, the number of branches per plant was not affected by thinning, being greater at lower planting densities on account of less competition. Thinned plants achieved higher averages of fresh shoot weight. Nevertheless, shoot dry biomass was greater at higher planting densities. Furthermore, both fresh and dry weight of roots were not influenced by any of the adopted treatments. © 2016, Universidade Federal Rural do Semi-Arid. All rights reserved.29487888

IL-1β, TNF-α, TGF-β, and bFGF expression in bone biopsies before and after parathyroidectomy

IL-1β, TNF-α, TGF-β, and b FGF expression in bone biopsies before and after parathyroidectomy.BackgroundThere is growing evidence pointing to an involvement of cytokines and growth factors in renal osteodystrophy. In this study, the expression of interleukin-lβ (IL-1β), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and basic fibroblast growth factor (bFGF) in bone biopsies taken from uremic patients before and 1 year after parathyroidectomy (PTX) was evaluated. Biochemical features and histomorphometric outcome were also studied.MethodsIliac bone biopsies were taken before and 1 year after PTX in nine uremic patients with severe hyperparathyroidism (HPT). Immunohistochemical techniques were used to identify the expression of IL-1β, TNF-α, TGF-β, and bFGF in these bone samples.ResultsAt the time of the second bone biopsy, the mean serum total alkaline phosphatase activity was normal, whereas mean serum intact parathyroid hormone (iPTH) level was slightly above the upper limit of normal values. Histomorphometric analysis showed a decrease in resorption parameters and static bone formation parameters after PTX. Dynamically, mineral apposition rate (MAR) and mineralization surface (MS/BS) decreased significantly. There was a marked local expression of IL-1β, TNF-α, TGF-β, and bFGF in bone biopsies before PTX, particularly in fibrous tissue and resorption areas. One year after PTX, IL-1β decreased from 23.6 ± 7.5% to 9.9 ± 3.1%, TNF-α from 4.5 ± 1.5% to 0.7 ± 0.8%, TGF-β from 49.6 ± 9.8% to 15.2 ± 4.6%, and bFGF from 50.9 ± 12.7% to 12.9 ± 7.9% (P < 0.001). A significant correlation was documented between cytokines and growth factors expression in bone with iPTH levels before and after PTX (P < 0.05).ConclusionsBased on these results, we suggest that IL-1β, TNF-α, TGF-β, and bFGF are involved in bone remodeling regulation, acting as local effectors, possibly under the control of PTH