Avaliação das condições de preparação de complexos polieletrolíticos utilizando extratos ou polímeros com origem marinha

Os polímeros de origem marinha, como o fucoidan, carragenina e quitosano podem ser utilizados em aplicações muito diversas, seja, por exemplo, como produtos dietéticos ou na cicatrização de feridas. Também têm sido propostos para a produção de sistemas de veiculação de fármacos, como as nanopartículas, tirando vantagem do potencial elevado de biodegradação, biocompatibilidade, baixa toxicidade e das várias atividades biológicas que lhes estão associadas. As algas são uma das possíveis fontes de polímeros marinhos. Um dos objetivos deste trabalho consistiu em avaliar a capacidade dos extratos de Sargassum muticum (FSm) para a formação de nanopartículas poliméricas com quitosano (CS), caraterizando-as quanto ao tamanho, índice de polidispersão e potencial zeta. Foram variados os rácios de massa (FSm/CS = 4/1, 1/1 e 1/4), tendo-se obtido tamanhos compreendidos entre 280 e 1040 nm, índices de polidispersão desde 0,23 a 0,66 e valores de potencial zeta entre +33 e +67 mV. Verificou-se uma tendência de aumento de todos estes parâmetros quando estava presente uma maior concentração de CS e, consequentemente, também uma maior concentração total de polímeros. Para estudar a influência da temperatura de reação nas características físico-químicas das nanopartículas foram produzidas nanopartículas com fucoidan obtido a partir de Fucus vesiculosus (FFv) e CS, e também com carragenina (CRG) e CS, fazendo-se uma comparação entre a produção à temperatura ambiente (25 ºC) e a uma temperatura controlada (15 ºC). As nanopartículas FFv/CS demonstraram que a concentração dos polímeros influenciou as suas propriedades físico-químicas, sendo que os parâmetros analisados (tamanho, índice de polidispersão, potencial zeta) aumentaram com a adição de CS. No entanto, verificou-se que nas nanopartículas CS/FFv o efeito no tamanho e potencial zeta foi o inverso quanto maior a proporção de CS. A comparação dos parâmetros de caraterização das nanopartículas após produção a ambas as temperaturas, indicou que a temperatura de reação não é um fator com muita influência nas caraterísticas das nanopartículas.Polymers from marine origin, such as fucoidan, carrageenan and chitosan can be used in very diverse applications, for example as dietary products or in wound healing. They have also been proposed for the production of drug delivery systems, such as nanoparticles, taking advantage of their high potential for biodegradation, biocompatibility, low toxicity, and their various associated biological activities. Algae are one of the possible sources of marine polymers. One of the objectives of this work was to evaluate the ability of Sargassum muticum (FSm) extracts to form polymeric nanoparticles with chitosan (CS), characterizing them in terms of size, polydispersity index and zeta potential. Mass ratios were varied (FSm/CS = 4/1, 1/1 and 1/4), and sizes ranging from 280 to 1040 nm, polydispersity index from 0.23 to 0.66 and zeta potential values between +33 and +67 mV were obtained. There was a tendency for all these parameters to increase when a higher concentration of CS was present and, consequently, also a higher total polymer concentration. To study the influence of the reaction temperature on the physicochemical characteristics of the nanoparticles, nanoparticles were produced with fucoidan obtained from Fucus vesiculosus (FFv) and CS, and also with carrageenan (CRG) and CS, making a comparison between the production at room temperature (25 ºC) and at a controlled temperature (15 ºC). The FFv/CS nanoparticles showed that the concentration of the polymers influenced their physicochemical properties, with the analyzed parameters (size, polydispersity index, zeta potential) increasing with the addition of CS. However, it was found that in the CS/FFv nanoparticles the effect on size and zeta potential was the reverse the higher the proportion of CS. Comparison of the characterization parameters of the nanoparticles after production at both temperatures indicated that the reaction temperature is not a factor with much influence on the nanoparticle characteristics

Comparative analysis of anatomical characteristics and phenolic compounds of two highbush blueberry (Vaccinium corymbosum L.) cultivars with different rooting ability of semi-hardwood cuttings

There is no information on morphological, anatomical or phenolic concentration differences between blueberry cultivars that could be related to the differential rooting responses. In the present work, such differences were evaluated comparing the rooting zones of cuttings from two blueberry cultivars ('Jewel' and 'Violeta' with 4n and 2n ploidy level, respectively). The parameters were measured during 150 days of rooting (rooting day after cutting insertion; RAI) at 30-day interval after treatment with 3 g/L of IBA. Stem length, stem diameter and number of leaves and buds were measured and tissue sections from cuttings were stained to measure tissue thickness. Also, the total phenolic content (TPC) by Folin-Ciocalteu method and the phenolic profile by liquid chromatography coupled to a diode array detection were also evaluated in rooting zones. 'Jewel' rooted earlier and in higher percentage than 'Violeta'. ANOVA showed that phenolic compounds, in a higher extent, and some morphological and anatomical parameters, in a lower extent, had a positive effect on rooting capacity. In both blueberry cultivars, the cuttings with the highest phenolic content presented an early rooting capacity. The multivariate analyses allowed us to corroborate these results. FiPLS selected common variables (coumaric acid and stem diameter) and specific variables depending on the cultivar (gallic acid, stem length and number of leaves for 'Jewel'; and, vanillic acid, rutin, and cortex thickness for 'Violeta'). PCA allowed to group the 'Violeta' samples (unrooted and rooted at 60, 90, 120 and 150 RAI) in compact homogeneous clusters with an adequate explanation rate (44.7 %). From all parameters, stem diameter seems to be inversely related, and cortex thickness and p-coumaric acid and rutin seems to be positively related to the earliest rooting day after insertion (RAI 60), while the largest the stem, the earlier the rooting. In future works, more cultivars and other parameters and phenolic compounds that can induce the rooting in cuttings, including their evolution over time, should be investigated.info:eu-repo/semantics/publishedVersio

Produzir alface sem solo, ou quem não tem cão caça com gato

Há várias técnicas para cultivar alfaces em casa e desfrutar de uma salada sempre fresca e acabada de colher. Escolha a melhor opção para o seu caso – cultivo em substrato ou em filme de água - em função do espaço e tempo disponíveis.info:eu-repo/semantics/publishedVersio

The effect of resource slack on organizational decline of large Brazilian companies: the moderating effect of the industry’s dynamic

Purpose This study aims to investigate the influence of resource slack on the decline of Brazilian companies, with a particular focus on the moderating role of environmental dynamism. The authors specifically examine three types of resource slack: available, potential and recoverable. These represent surplus resources that exceed what is necessary for the organization's basic operations. The role of environmental dynamism, characterized by rapid changes in customer preferences, technologies and competitive dynamics, is considered as a moderating factor in this relationship. Design/methodology/approach. The authors used data from Brazilian companies spanning from 1997 to 2008. The research sample was composed using the matching-pairs method, which included a group of publicly traded companies that experienced decline (43 companies) and a group that did not (40 companies) within the specified timeframe. Findings Findings of this study indicate that the presence of available slack, being more liquid resources, decreases the likelihood of organizational decline. Furthermore, the moderation effect of potential resource slack can mitigate decline in companies operating in dynamic industries. Originality/value This research provides valuable insights into the impact of slack resources on potential organizational turnarounds. Given the relative scarcity of resources in these companies compared to those in developed countries, whether they be financial, human or technological, the study highlights the unique influence of slack in a less explored institutional environment. This research underscores the importance of examining the decline of Brazilian companies from a broader perspective, emphasizing that decisions regarding resource use can have significant implications on a company's trajectory, either amplifying or mitigating its decline.Processo 302352/ 2022-8, CAPES: Finance Code 001, FURB: Projeto 609/2021.info:eu-repo/semantics/publishedVersio

Plant-based silver nanoparticles ecotoxicity: perspectives about green technologies in the one health context

Silver nanoparticles (AgNPs) have extensive applications in nanomedicine and parasitology, particularly as antifungal, bactericidal, antiviral, larvicidal, mosquitocidal, and tick-killing agents. Plant-based AgNPs (PB-AgNPs) have been studied as a safer and biocompatible strategy to collaborate in disease control. However, knowledge concerning the toxicity of PB-AgNPs in non-target organisms is still limited. A scientometric and systematic review was conducted to comprehensively understand the potential toxicity associated with these nanoparticles. In brief, the assessment of PB-AgNPs toxicological and ecotoxicity aspects needs to be aligned with their development for target organisms. Our review demonstrates that different PB-AgNPs can cause lethal and sublethal effects like increased oxidative stress, cardiotoxicity, neurotoxicity, hepatotoxicity, hematotoxicity, and, DNA damage, alongside others, particularly in aquatic organisms. Besides, the toxicity of PB-AgNPs for terrestrial and some aquatic organisms remains poorly understood. Additionally, the similar LC50 range between non-target aquatic organisms and target organisms highlights the potential ecological impact of PB-AgNPs. Comprehensive toxicological assessments and further research are crucial to ensure the safe and sustainable use of PB-AgNPs in a One Health context.Fundação de Amparo a Pesquisa do Estado do Goiás (FAPEG) 05/2020, 202110267000294, Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPQ) 28/2018, 433553/2018-9, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) 001, Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPQ) 306329/2020-4info:eu-repo/semantics/publishedVersio

Podem as abelhas resolver o problema causado pelo excesso de néctar na framboesa?

As flores da framboesa produzem por vezes uma abundante quantidade de néctar no qual se podem desenvolver fungos e bactérias que desvalorizam os frutos (Figura 1). É suposto que as abelhas possam contribuir para reduzir este problema, pois na sua actividade, além de pólen, recolhem também o néctar. Contudo, poderão as abelhas ser eficazes na resolução deste problema, conseguindo reduzir o néctar em excesso?info:eu-repo/semantics/publishedVersio

Valorização de resíduos agrícolas por compostagem: o caso da laranja

A compostagem é um processo biológico de transformação da matéria orgânica, controlado, aeróbio, desenvolvido sobretudo por microrganismos, que compreende habitualmente um período de temperatura elevada, acima de 45 ºC. A compostagem permite valorizar resíduos orgânicos, em particular de origem agrícola, transformando-os em produtos de elevado valor para melhorar a fertilidade dos solos. As laranjas não comercializáveis, e outros citrinos, são frequentemente referidas como não sendo adequadas para compostar. Contudo, a prática demonstra que a compostagem de misturas com resíduos com laranjas é um processo tão fácil como a de outros materiais, obtendo-se compostos de elevado interesse para os solos ou como componentes de substratos hortícolas, contribuindo para a circularidade na agricultura.info:eu-repo/semantics/publishedVersio

The relationship between soft skills, stress and reduced audit quality practices

PurposeThis study aims to identify the effect of soft skills as a driver of audit quality and their moderating role in the relationship between stress and the propensity for auditors to engage in reduced audit quality practices (RAQP).Design/methodology/approachThis study uses a sample of 130 auditors, whose data were collected through an electronic questionnaire. The results were derived from the partial least squares-structural equation modelling method.FindingsThe findings show that the propensity to incur RAQP increases when auditors are under job stressors but decreases when individuals have resilience and time management skills. Moreover, the results suggest that the moderating effect of these two soft skills can effectively reduce the auditors' propensity to engage in dysfunctional actions and judgments in auditing. Emotional intelligence and self-efficacy skills are shown not to affect RAQP.Originality/valueThis study adds to previous research on auditors' drivers for supplying audit quality, by providing evidence of auditor characteristics as a critical input to audit quality. The results emphasize the importance of researchers including in models the moderating effect of soft skills on the relationship between audit quality and determinants associated with audit firms, clients or the regulatory framework.info:eu-repo/semantics/publishedVersio

Sustainable extraction of polyphenols from vine shoots using deep eutectic solvents: influence of the solvent, vitis sp., and extraction technique

Vine shoots are the main by-products of grapevine pruning with no added value. In the present study, deep eutectic solvents (DESs) were used as alternatives to traditional chemical solvents, for the extraction of phyto chemicals from grapevine shoots. Three levulinic acid-based DESs were tested for the first time, and their per formance was compared to methanol (a standard chemical solvent) regarding the extraction of phenolic compounds from thirteen Vitis sp. shoots. Two extraction methods have been applied: ultrasound-assisted extraction and solid-liquid extraction. A total of eleven polyphenols which belongs to four families (proantho cyanins, stilbenes, hydroxycinnamic acids, and flavonols) have been identified and quantified in the extracts. The statistical analysis shows that the levulinic acid-based DES systems are novel and important alternatives to chemical solvents due to favourable eco-friendly properties and remarkable extraction performance of poly phenols. On the other hand, the ultrasound-assisted extraction technique has significantly increased the extraction rate in comparison to the solid-liquid extraction method with p-values lower than 0.05 for most compounds. The genetic factor has been shown to play an important role in the content of extracted polyphenols, being V. riparia pubescente the one that presented the highest concentrations of extracted polyphenols. Finally, the polyphenol-enriched extracts have proven important properties such as antioxidant activity and significant delay in bacteria growth against both gram-positive and gram-negative bacteria. It is important to note that, to the best of our knowledge, this is the first time that deep eutectic solvents have been used for the extraction of bioactive compounds from vine shoot residues.UCA/R155REC/2021;info:eu-repo/semantics/publishedVersio

Seasonal and geographic dynamics in bioproperties and phytochemical profile of Limonium algarvense Erben

This study delved into the influence of ecological and seasonal dynamics on the synthesis of secondary metabolites in the medicinal halophyte Limonium algarvense Erben, commonly known as sea lavender, and examined their antioxidant and anti-inflammatory properties. Aerial parts of sea lavender were systematically collected across winter, spring, summer, and autumn seasons from distinct geographic locations in southern Portugal, specifically “Ria de Alvor” in Portimão and “Ria Formosa” in Tavira. The investigation involved determining the total polyphenolic profile through spectrophotometric methods, establishing the chemical profile via liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS), and evaluating in vitro antioxidant properties using radical and metal-based methods, along with assessing anti-inflammatory capacity through a cell model. Results unveiled varying polyphenol levels and profiles across seasons, with spring and autumn samples exhibiting the highest content, accompanied by the most notable antioxidant and anti-inflammatory capacities. Geographic location emerged as an influential factor, particularly distinguishing plants from “Ria de Alvor”. Seasonal fluctuations were associated with environmental factors, including temperature, which, when excessively high, can impair plant metabolism, but also with the presence of flowers and seeds in spring and autumn samples, which also seems to contribute to elevated polyphenol levels and enhanced bioproperties of these samples. Additionally, genetic factors may be related to differences observed between ecotypes (geographical location). This study underscores sea lavender’s potential as a natural source of antioxidant and anti-inflammatory agents, emphasizing the significance of considering both geographic location and seasonal dynamics in the assessment of phenolic composition and bioactive properties in medicinal plant species.info:eu-repo/semantics/publishedVersio