Browsing by Issue Date, starting with "2023-09-22"
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- Dixon-Rosenfeld lines and the standard modelPublication . Chester, David; Marrani, Alessio; Corradetti, Daniele; Aschheim, Raymond; Irwin, KleeWe present three new coset manifolds named Dixon-Rosenfeld lines that are similar to Rosenfeld projective lines except over the Dixon algebra C⊗H⊗O. Three different Lie groups are found as isometry groups of these coset manifolds using Tits’ formula. We demonstrate how Standard Model interactions with the Dixon algebra in recent work from Furey and Hughes can be uplifted to tensor products of division algebras and Jordan algebras for a single generation of fermions. The Freudenthal–Tits construction clarifies how the three Dixon-Rosenfeld projective lines are contained within C ⊗ H ⊗ J2(O), O ⊗ J2(C ⊗ H), and C ⊗ O ⊗ J2(H). $$\mathbb {C}\otimes \mathbb {H}\otimes \mathbb {O}$$ C ⊗ H ⊗ O . Three different Lie groups are found as isometry groups of these coset manifolds using Tits’ formula. We demonstrate how Standard Model interactions with the Dixon algebra in recent work from Furey and Hughes can be uplifted to tensor products of division algebras and Jordan algebras for a single generation of fermions. The Freudenthal–Tits construction clarifies how the three Dixon-Rosenfeld projective lines are contained within $$\mathbb {C}\otimes \mathbb {H}\otimes J_{2}(\mathbb {O})$$ C ⊗ H ⊗ J 2 ( O ) , $$\mathbb {O}\otimes J_{2}(\mathbb {C}\otimes \mathbb {H})$$ O ⊗ J 2 ( C ⊗ H ) , and $$\mathbb {C}\otimes \mathbb {O}\otimes J_{2}(\mathbb {H})$$ C ⊗ O ⊗ J 2 ( H ) .
- Citrus Pruning in the Mediterranean climate: a reviewPublication . Matias, Pedro; Barrote, Isabel; Azinheira, Gonçalo; Continella, Alberto; Duarte, AmilcarPruning is a common practice in citrus for various reasons. These include controlling and shaping the canopy; improving phytosanitary health, productivity, and fruit quality; and facilitating operations such as harvesting and phytosanitary treatments. Because pruning is an expensive operation, its need is sometimes questioned. However, it has been proven to be particularly important in Mediterranean citriculture, which is oriented towards producing fruits for a high-quality demanding fresh market. Herein, we summarize and explain the pruning techniques used in Mediterranean citriculture and refer to the main purposes of each pruning type, considering citrus morphology and physiology.
- Solvent assessment and selection in terms of sustainability, performance, and cost: Design of a solvent database in a pharmaceutical environmentPublication . Obregón Gutiérrez, Gisela; Mendonça, Ricardo; Garcia, Ana Rosa GalegoIncreased environmental awareness has, since the end of the 1980s, helped shift the paradigm from waste remediation to waste prevention. The introduction of the green chemistry concept and the publication of the twelve principles in the 1990s has been particularly embraced by the pharmaceutical industry, where typically between 25 and 100 kilograms of waste are generated per kilogram of product (ratio known as the E-factor). In this context, several manuals and guides that intend to evaluate solvents and facilitate their selection have been released, published both by individual companies (e.g., Pfizer, GSK, AstraZeneca) and working groups (e.g., ACS GCI-PR, CHEM21). In alignment with these efforts, a novel solvent selection and assessment tool was developed, tailored to suit Hovione’s unique context. The target audience was defined as anyone working with solvents, but particularly scientists looking to choose solvents for new or existing applications. A list of 50 solvents currently in use in Hovione was compiled and served as the basis for the database. For each entry, a list of 49 various chemical, thermodynamical, environmental, and regulatory data points was included. Furthermore, the tool incorporated a new unified assessment method across four categories, considering the danger that the solvent poses to workers’ health, the risk to the process safety, the environmental impact, and a sustainability analysis. Each evaluation was customizable by the user, in order to prioritize specific aspects of each exercise. In addition, each solvent was then ranked as recommended, problematic, hazardous, or highly hazardous. The final recommendations provided by the algorithms included in the tool correlated well with recommendations from other published solvent guides. These smaller assessments and final recommendations will aid scientists in comparing solvents against each other, as well as help them consider precautionary steps in case a contentious solvent is chosen for an application.
- Searching for Bioactive Compounds in the Microalgae Nanofrustulum shiloiPublication . Nwankpa, Ugonna Darlington; Barreira, Luísa AfonsoHypertension remains the greatest risk factor of cardiovascular diseases (CVDs) and the roles of angiotensin converting enzyme (ACE), oxidative stress and cardiovascular inflammation in its etiology are well established. Current hypertension medications present some side effects such as increased risk of hyperkalemia, dry cough, and angioedema, and thus the search for alternative therapies is needed, especially with the increasing emphasis on natural alternatives. Nanofrustulum shiloi is an understudied microalga, but a sustainable and economic repository of nutritive chemicals such as pigments, poly-unsaturated fatty acids (PUFAs), etc., and has been found to inhibit ACE, in a previous study.
- Isolation and identification of bioactive compounds from microalgaePublication . Valverde, Segismundo García; Barreira, LuísaMicroalgae are an untapped resource with numerous potential commercial applications in biofuels production, drug discovery and production, food and feed, cosmetics, and environmental remediation, among other fields. They display unique properties such as tuneable growth rates and biochemical composition, higher photosynthetic efficiency than higher plants, and low water intensity cultivation. Also, there is a wide variety of microalgae species that can be cultivated in diverse environmental conditions, and it is estimated that most of the species have not been described yet. In short, the cultivation of microalgae offers a green alternative to many goods, products, and processes.
- Substitution of problematic solvents with greener options for industrial applicationsPublication . Al-Kubati, Abdulrahman Badr Hasan; Garcia, Ana Rosa; Mendonça, RicardoPeptide production stands as one of the most vital and rapidly growing sectors within the pharmaceutical industry, offering a wide array of therapeutic applications. The conventional methods of peptide synthesis rely heavily on organic solvents, such as N,N-dimethylformamide (DMF), N-methyl pyrrolidone (NMP), and dichloromethane (DCM), leading to significant generation of hazardous waste. However, their adverse effects on human health and the environment, as well as their substantial carbon footprint, have prompted the need for greener alternatives. Micellar chemistry, with water as the solvent, provides a promising alternative to traditional organic solvents, mitigating the adverse environmental impacts associated with conventional approaches. In this study, commercially available surfactants in water were investigated for their potential in facilitating a simple peptide coupling reaction. Different coupling agents and reaction parameters, such as time and surfactant solution amount, were explored. Co-solvents and binary surfactant systems were also examined to enhance reaction efficiency and selectivity. The success of the peptide coupling reactions was evaluated through product yields and analysis using proton nuclear magnetic resonance (H-NMR) spectroscopy, confirming the effectiveness of surfactant-based systems in promoting desired coupling reactions.