Hatem Gaffer, Mounir Salem and Magda Marzouk
The present study aims to focus on the possibility of developing new eco-friendly azo dyes with good colouristic application properties, exhibiting biological and pharmacological…
Abstract
Purpose
The present study aims to focus on the possibility of developing new eco-friendly azo dyes with good colouristic application properties, exhibiting biological and pharmacological activities.
Design/methodology/approach
Coupling of 4-hydroxycoumarin with a variety of aromatic diazonium salts of 2-aminothiazole, 2-aminobenzothiazole, 4-aminoantipyrine, 4-aminoacetophenone, adenine sulphate, a-naphthylamine and sulphadimidine to produce novel azo dyes. The compounds were fully characterised using spectroscopic and analytical methods. All of the compounds were tested for their antimicrobial, anticancer and antioxidant activities. The prepared dyestuffs were dyed on polyester fabrics and subsequently their dyeing properties, light, washing, perspiration, rubbing and sublimation fastness were determined.
Findings
The spectroscopic data of the synthesised compounds have provided decisive evidence that such compounds exist in the solid state as the azo-dike to form C and in solution in equilibrium tautomer forms A, B and D. The prepared dyestuffs are suitable for either heat transfer printing or traditional printing on polyester and nylon 6 fabrics. The prints obtained from the dyes possess high colour strength, as well as good overall fastness properties. Also the synthesised compounds exhibit good biological and pharmacology activity.
Research limitations/implications
Synthesis of these seven azo dyes for textile dyeing had never been reported previously.
Practical implications
The dyestuffs derived from 4-hydroxycoumarin are reasonable azo disperse dyestuffs giving good all round fastness properties on polyester fabrics.
Social implications
Production of less expensive and new eco-friendly dyes exhibit antimicrobial and anticancer activity.
Originality/value
It provided a potentially simple way to synthesize novel coumarin azo-dyes exhibit good biological and pharmacology activity and also exhibit good overall fastness properties.
Details
Keywords
Azaiez Ouled Belgacem, Farah Ben Salem, Mouldi Gamoun, Roukaya Chibani and Mounir Louhaichi
The purpose of this paper is to illustrate the benefits of reintroducing traditional grazing systems practices for improving arid rangelands. Grazing is the most extensive land…
Abstract
Purpose
The purpose of this paper is to illustrate the benefits of reintroducing traditional grazing systems practices for improving arid rangelands. Grazing is the most extensive land use in southern Tunisia, but the rangelands have suffered many decades of severe degradation due to profound socioeconomic changes and the emergence of an agro-pastoral society in place of the former pastoral one. Traditional grazing systems (gdel and herd mobility), which had historically allowed for grazing deferment and control of grazing livestock were abandoned. Yet grazing management strategies are important tools to sustain integrated livestock rangeland production systems in dry areas in the face of ongoing climate change and human pressure.
Design/methodology/approach
This study assesses the revival of traditional best practices of rangeland resting in a representative community. Total plant cover, species composition, flora richness and range production were determined in six rangeland sites subjected respectively to one, two and three years of rest; one and two years of light grazing after rest; and free grazing (control).
Findings
Results showed that dry rangelands keep their resilience to the negative effects of climate change once human pressure is controlled. A maximum of two years of rest is enough to sustainably manage the rangelands in southern Tunisia, as this protection showed considerable and positive effects on the parameters scored.
Originality/value
The revival of the traditional best practices under new arrangements adapted to current biophysical and socioeconomic conditions would be an excellent tool to mitigate the negative effects of frequent droughts and reduce the animal feed costs that poor farmers face.
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Mohsen Anwar Abdelghaffar Saleh and Dejun Wu
This paper aims to examine the relationship between corporate COVID-19 disclosure (COVID_DISC) and stock price volatility (SPV) in Egypt.
Abstract
Purpose
This paper aims to examine the relationship between corporate COVID-19 disclosure (COVID_DISC) and stock price volatility (SPV) in Egypt.
Design/methodology/approach
The authors used the manual content analysis method to measure corporate COVID-19 disclosure in the narrative sections of annual reports. The authors use ordinary least squares (OLS) regression to examine the impact of corporate COVID-19 disclosure on stock price volatility using unique data from Egyptian-listed firms during COVID-19 pandemic over the period of 2020 to 2022. Propensity score matching method was adopted to mitigate the potential endogeneity issue.
Findings
This study reveals that corporate COVID-19 disclosure has a significant negative impact on stock price volatility, suggesting COVID-19 disclosure reduces stock price volatility. In addition, the results confirm that COVID-19 disclosure offers value relevant information to investors, which is consistent with the Egyptian Financial Supervisory Authority’s (EFSA) motivation in calling for more information on COVID-19 pandemic.
Practical implications
The findings of this study can help corporate managers and EFSA in enhancing corporate disclosure and transparency during future financial crises. Moreover, the findings offer valuable insights to investors, helping them gain a better understanding of the business environment during COVID-19 crisis.
Originality/value
To the best of the authors’ knowledge, this is the first Egyptian empirical evidence that examines the relationship between corporate COVID-19 disclosure and stock price volatility.