Immobilization of laccase from Trametes hirsutus on allumina and decolourisation of textile dyes for colour removal on effluent

Laccase (EC 1.10.3.2) is a multicopper oxidase which reduces oxygen to water and simultaneously performs one-electron oxidation of many aromatic substrates [7]. Laccases catalyze the removal of a hydrogen atom from the hydroxyl group of methoxy-substituted monophenols , ortho- and para-diphenols, but it be able also to oxidize other substrates such aromatic amines, syringaldazine, and non-phenolic compounds to form free radicals [8]

Plasma-assisted deposition of antimicrobial silver nanoparticles on medical textiles

Two of the major problems in worldwide hospitals are the healthcare-associated infections (HAIs) and the skin and soft tissue infections (SSTIs). Every year mortality rates and health costs related to HAIs and SSTIs increases. Furthermore, the antibiotic resistance is moving faster than the development of new efficient antibiotic agents so, alternatives, for antimicrobial action, are urgently needed. Silver nanoparticles (AgNPs) have been used as antimicrobial agent in wound and burn dressings, surgical sutures and medical staff uniforms revealing a noble effect on Gram positive and Gram-negative bacteria, virus and fungi, including various drug resistant strains. AgNPs have improved properties compared with larger particles that allow a unique action due to the high surface to-volume ratio. However, there are some significant problems related with AgNPs based antimicrobial textiles due to the uncontrolled immbolization and release of AgNPs leading to excessive exposure. Several methods are used to incorporate AgNPs into fabrics, however, they often consume many chemicals, energy, time and usually required special equipment and have weak adhesion to the substrate. Dielectric barrier discharge (DBD) plasma treatment can be efficiently used as a pretreatment to activate the surface of the fabrics and improve the AgNPs adhesion. This is a dry environmental friendly and low cost technology since it may be produced at ambient conditions without any chemical product

China's foreign policy towards Central Asia: expanding the concepts of national interest and national security

The present study provides an analysis of China’s foreign policy towards Central Asia to trace ‘culture of China’s foreign policy’. The culture of China’s foreign policy approach deals with China as an identity and process rather than being static or within boundaries. The present research highlights China’s multilateral and cooperative policies in Central Asia and with Russia as an outcome of evolutionary process of construction of China’s identity. The complex process of building relations with Central Asian region although within a short period of time (in post-Soviet context) are analysed to make a case for China’s innovative (partially) political processes of dealing with frontier security and embracing multilateralism. This is explained by studying the evolution of China’s identity and interests and the role of significant events that affect its perceptions of self and that are a prescription for its policy orientations as observed in case of foreign policy towards Central Asia. The theoretical foundation of Peter Katzenstein thesis is helpful premises upon which an argument in favour of the discourse of identity and security is developed to see how culture of national security of China and ‘complementarity’ of Central Asian states is at work in security cooperation seen among these states. By problematizing the notion of ‘national interest’, the present study argues that interests of the states can be contextualized in a broader environment referred as civilization to trace the relationship between interests and identities of China as at play in Central Asian region. By placing the political state of ‘China’ in the broader context of civilization and as evolving, helps understand how Chinese political spectrum seeks to construct and maintain a great power identity while locating ‘self’ against ‘others’. It further argues that the cooperative and multilateral policies of China in form of Shanghai Cooperation Organization can be understood best by studying how the configurations of identity of China has guided the policy formation process; that constructs and reconstructs interstate normative structure in form of SCO

Desenvolvimento de espaços para a esterilização por irradiação ultravioleta-C (UV-C) em larga escala de Equipamentos de Proteção Individual (EPIs) nos hospitais para a sua reutilização

UV-Fast: Development of spaces for large-scale sterilization by ultraviolet-C (UV-C) irradiation of personal protective equipment (PPE) in hospitals for their reuse Desenvolvimento de espaços para a esterilização por irradiação ultravioleta-C (UV-C) em larga escala de Equipamentos de Proteção Individual (EPIs) nos hospitais para a sua reutilização FCT Project Research4Covid-19 Reference: 011_59580300

The Effect of Covid-19 on the Probability of Default of South African Firms Listed on the Johannesburg Stock Exchange (JSE)

The aim of this study is to quantify and investigate the effect of the Covid-19 pandemic on non-financial South African firms listed on the Johannesburg Stock Exchange. The study implemented the Merton (1974) model on the 59 largest non-financial firms and calculated the probability of default for each firm before the pandemic and during the pandemic as at each firm's financial year-end. The default probabilities are calculated predominantly from the value and volatility of firm equity. The results emphasize that the Covid-19 pandemic, on average, had a dramatic impact on the probability of default of publicly traded South African firms. The observed increase in default probability was found to be statistically significant at the 5% significance level

Surface chemistry of nanocellulose and its composites

Cellulose is recurrently defined as the most abundant biopolymer on planet Earth, displaying an overall estimated production rate of more than 0.2 billion tons in a single day. Cellulose prompt availability allied to it its mechanical properties made it virtually indissociable from the majority of anthropogenic commodities. Nevertheless, continuous progress demands superior features form daily common materials, being most of them adequately suited by low-cost petrochemical polymers. Fortunately, the higher Environmental awareness of the global population as well as 1 the remarkable properties of biosynthesized polymers, has driven an extensive research on a plethora of biopolymers, including cellulose. Cellulose most notable features are associated to its crystal domains, which are impressively underscored with the development of cellulose nanotechnology. Moreover, at nanoscale the cellulose surface richness in hydroxyl groups is comprehensively more available, considerably t broadening he effectiveness and potential of their interaction per se, but also by enhancing the efficacy of surface modification and functionalization. Nanocellulose surface modification was implemented almost contemporary to its discovery and characterization, and its objectives ranged between improving yield of nanocellulose production, lower its production costs, and to provide nanocellulose a completely distinct surface properties by changing its polarity, generating different functional groups, decorating it with adsorbed or tightly bound nanoparticles, and to provide additional chemical compatibility with distinct compounds to generate advanced nanocomposites. The plethora of successfully reported modifications and functionalizations underscore notable properties of both modified nanocellulose and its composites. This Chapter intends to highlight these remarkable features, hopefully widening the scope of novel applications of these impressive bio-based polymers

The urgency of measuring fluorinated greenhouse gas emission factors from the treatment of textile and other substrates

The fashion industry is responsible for up to 10% of global CO2 emissions (Niinimäki et al., 2020), and according to the United Nations Framework Convention on Climate Change the sector's emissions are expected to rise by more than 60% by 2030 (UNFCCC 2018). While the vast majority of the sector's carbon footprint results from CO2 emissions, an additional source – still unaccounted for and growing – likely results from emissions of fluorinated greenhouse gasses (F-GHGs) during the treatment of textile and leather. Indeed, fluorine-based treatment of fibers and other substrates (paper, metals, plastics, etc.) is increasingly performed using wet- or plasma-based methods to functionalize surfaces for water and oil repellence, soil and stain release, improved textile breathability, softening, dyeing ability, increased mechanical strength, reduced adherence, antibacterial and anti-odor properties, and to fabricate wrinkle-free materials. For more information see Chapter 8 of (IPCC 2019). Although F-GHG emissions only represent 2.6% of global greenhouse gas emissions, F-GHGs have long atmospheric life (up to 50,000 years for CF4) and high global warming potential (GWP, up to 23,500 for SF6). Thus, it is concerning that the atmospheric concentration of some of these gasses is higher than what is predicted through bottom-up analyses i.e., when estimating emissions using the 2006 IPCC Guidelines for National GHG Inventories for all processes and industrial sectors known to emit F-GHGs. During the 2015–2016 Technical Assessment of the 2006 IPCC Guidelines, potential emissions from the textile industry were accounted, among others, as a possible reason for the gap between top-down and bottom-up estimates of F-GHG emissions (IPCC 2016). Surprisingly, although several international and national reports refer to possible atmospheric emissions of F-GHGs during finishing of textile, carpet, leather, and paper, no corresponding emission factors (EFs) were found to have been measured and published in the open literature. For more information see Chapter 8 of (IPCC 2019). While the existing literature on the environmental impacts of textile finishing processes typically focuses on formaldehyde emissions, total volatile organic compounds (VOCs) release, and the impacts of a limited number of long chains perfluoroalkane sulfonic acids (PFASs) such as perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA), and their precursors, the literature is silent on the potential climate impacts of these compounds and other fluorinated surface treatment chemicals. Fluorinated wet treatment processes include several application techniques but about 80% of the processes use the pad-dry-cure method, where the dry fabric is immersed in a F-based finishing liquor and then squeezed between rollers before being dried and finally cured, usually at temperatures up to 180 °C. Chemicals used for wet treatment processes include fluorotelomer alcohols, and perfluoroalkyl carboxylic acids. Although such chemicals may not be GHGs by themselves, it is unclear whether fluorinated ethers, unreacted monomers or by-products formed during the deposition processes, and in the atmosphere, can produce relevant F-GHGs. For more information see Appendix 1 of (IPCC 2019). Notwithstanding, it has been proved that during the drying and curing phases, F-based off-gas emissions can be produced by the volatility of the active substances themselves as well as by their constituents through evaporative losses and cracking. For more information see Appendix 1 of (IPCC 2019). Moreover, high-GWP perfluoropolyethers were identified as being used in a number of commercial applications, including for textile treatment, increasing the concerns about the atmospheric release of these compounds. For more information see Chapter 6 of (IPCC 2019). Recently, due to the persistent and bio-accumulative nature of the chemicals used in wet-based treatment processes, several manufacturers have developed alternate plasma-based treatments for specialized fibers and substrates (Tudoran et al., 2020). Plasma technology can be tailored to achieve many desirable properties and may provide equal or even better performance than wet methods. Plasma processes can be divided into three process types: (1) plasma treatment, (2) plasma polymerization and (3) plasma etching. Plasma treatment and polymerization are the main processes of concern because they can use large quantities of F-GHG feedstocks such as CF4, C2F6, C3F6, C3F8, C4F8, C5F10, CHF3, SF6, and other larger molecules such as perfluoroalkyl acrylates to deposit thin films on a substrate. Because the application of high plasma power densities could damage fragile substrates, it is highly probable that feedstock molecules are not fully disassociated by the plasma. Further, the plasma disassociation of F-GHGs is well known to result in the formation of other F-GHG byproducts (e.g., of CF4 from C2F6). For more information see Appendix 1 of (IPCC 2019). Therefore, plasma-based fluorinated treatment of textile, carpet, leather, paper, and other substrates is expected to lead to higher F-GHG emissions than wet chemistry methods. The authors of the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories have proposed four distinct tiered methods (Tier 1, Tier 2a, Tier 2b, and Tier 3) to account for emissions from wet- and plasma-based fluorinated treatment of textile, leather, carpet, and paper. For more information see Appendix 1 of (IPCC 2019). However, because no Tier 1 or Tier 2 default (industry average) factors are available, only the Tier 3 method is currently practicable, using equipment-specific, process-specific, or site-specific measured emission factors. Measurements should preferentially be performed by Fourier transform infrared spectroscopy (FTIR) due to part per billion (ppb) sensitivity and portability or by gas chromatography followed by mass spectrometry (GC/MS), allowing near real time measurements. Without experimentally measured emission factors, it is not possible to estimate the potential global climate impact of the above-mentioned processes. Thus, there is a critical need of consistent research on the fate and atmospheric chemistry of volatile PFASs, fluorinated ethers, perfluoropolyethers and unreacted precursors and greenhouse gas by-products formed during the wet, plasma, and other thermal coating processes used for the fluorinated treatment of textiles and other substrates. Research should particularly focus on establishing a database of experimental emission factors that can be used to estimate GHG emissions per mass of input chemicals consumed, or per surface area or mass of substrates treated. Once a representative set of emission factors will have been measured, it will then be possible to derive default (industry-average) EFs that could be used to estimate industry-wide emissions. In parallel with the measurement of emission factors to establish the industry's baseline emissions, a coordinated research effort should be undertaken to mitigate climate impacts. Emissions reduction strategies could include – in decreasing order of priority from an ecological standpoint: (1) replacement (not using fluorinated precursors that may emit F-GHGs), (2) optimization (reducing emissions through process improvements), (3) capture and recycle, and (4) abatement. While replacement may prove difficult – especially for the most demanding applications –, optimization of processes to increase the utilization efficiency of fluorinated precursors certainly appears as a viable option, especially for plasma-based processes. Indeed, previous experience in optimizing F-based plasma processes in the electronics industry have proved that it is possible to increase the utilization efficiency of the precursors, thereby reducing their consumption and overall emissions, while lowering costs and improving productivity (e.g., through shorter processing times). For more information see Chapter 6 (IPCC 2019). Also, even if complete replacement of fluorinated chemistries may not always be possible, using alternate fluorinated precursors that are easier to disassociate (e.g., NF3 instead of CF4) or have lower GWPs (e.g., c-C5F8 instead of c-C3F6) can be viable options. While capture and recycling may be costly, abatement of F-GHGs is an established technology that offers low mitigation costs for high-GWP fluorinated gasses. Indeed, combustion-, catalytic-, absorption-, hot-wet-, and plasma-based abatement solutions have been developed to provide up to 99% destruction removal efficiencies (DREs), notably in the electronics industry. For more information see Chapter 6 of (IPCC 2019). Emissions of F-GHGs from wet- and plasma-based fluorinated treatment of textile, leather, paper fibers, and other substrates may be substantial due to the large volume of materials treated and the sheer size and global nature of these industrial sectors. It is therefore urgent to measure the corresponding emissions factors and to create a comprehensive international database of such factors in order to estimate and mitigate emissions from these yet-unaccounted-for sources.Centro de Ciência e Tecnologia Têxtil (2C2T) of the Universidade do Minho for the travel expenses reimbursement through the project UID/CTM/00264/2019 of the Portuguese Fundação para a Ciência e Tecnologia (FCT