Catalytic conversion of caffeine into molecules of valuable interest via N-demethylation reaction

This work aims to apply catalytic processes to promote the conversion of caffeine into valuable dimethylxanthines via N-demethylation reaction. Thus, we seek to evaluate the products formed and propose the reactions involved and their mechanisms. Reaction conditions were evaluated including different concentrations of Fenton reagent and ascorbic acid to evaluate caffeine oxidation. Theobromine, paraxanthine, and theophylline formation was proven by HPLC-DAD and mass spectrometry analysis evidencing the N-demethylation reactions, via radicals, with about 1 % yield. These results open the way for new N-demethylation reaction routes to be studied with applications for caffeine and other biomolecules in diverse areas such as biochemistry and medicinal chemistry. Application of the Fenton catalysis as alternative to promote the conversion of caffeine in other xanthines by N-demethylation. In this scenario was verified the capability of ascorbic acid in promoting same reaction, both environmentally friendly processes. This work investigates the possibility of using a well known biocompound as a precursor to obtain value added molecules.This study was financially supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 and by CIMO (UIDB/00690/2020) through FEDER under Program PT2020. In addition, the authors acknowledge Central de Análise e Prospecção Química – CAPQ and Laboratório Central de Biologia Molecular (LCBM), Chemistry Department/UFLA for their technical support. Jose L. Diaz De Tuesta acknowledges the financial support through the program of Atracción al Talento of Comunidad de Madrid (Spain) for the individual research grant 2022-T1/AMB-23946.info:eu-repo/semantics/publishedVersio

Partial derivative automata formalized in Coq

In this paper we present a computer assisted proof of the correctness of a partial derivative automata construction from a regular expression within the Coq proof assistant. This proof is part of a for- malization of Kleene algebra and regular languages in Coq towards their usage in program certification.Fundação para a Ciência e Tecnologia (FCT) Program POSI, RESCUE (PTDC/EIA/65862/2006), SFRH/BD/33233/2007

Kinetic insights on wet peroxide oxidation of caffeine using EDTA-functionalized low-cost catalysts prepared from compost generated in municipal solid waste treatment facilities

Nowadays, sorted organic fraction of municipal solid waste is typically treated by anaerobic digestion processes, resulting therein a solid stream, further processed to obtain compost, whose production is higher than the existing demand as fertilizer. The current work proposes an alternative strategy for the recovering of compost through the production of low-cost catalysts by calcination (1073 K) and sulfuric acid treatments, followed by sequential functionalization with tetraethyl orthosilicate (TEOS) and ethylenediamine tetraacetic acid (EDTA). Activity and stability of the catalysts are assessed in the wet peroxide oxidation of synthetic wastewater effluents contaminated with caffeine, a model micro-pollutant, achieving its complete removal after 6 h at 353– 383 K and catalyst loads of 0.5–2.5 g L−1. The increase of the catalytic activity of the materials upon functionalization with TEOS and EDTA is demonstrated and a kinetic modeling of caffeine degradation and hydrogen peroxide consumption with the best catalyst is assessed by pseudo-first power-law rate equations.This work was financially supported by project ‘‘VALORCOMP - Valorización de compost y otros desechos procedentes de la fracción orgánica de los residuos municipales’’, 0119_VALORCOMP_2_P, through FEDER under Program INTERREG; and CIMO (UIDB/00690/2020) through FEDER under Program PT2020.info:eu-repo/semantics/publishedVersio

Application of catalysts developed from compost derived from municipal solid waste in the removal of caffeine by wet peroxide oxidation

Nowadays, waste management through mechanical biological treatment (MBT) consists on the use of the separated organic fraction of municipal solid waste (MSW) to feed anaerobic digestion processes, resulting therein a solid stream, further processed to compost, which can be used as fertilizer. Currently, the production of compost from MBT is higher than the existing demand, and the expected developments on up-coming directives ruling “End-of-waste” criteria are leading to barriers on the use of waste-derived fertilizers (European Commision, 2013). In this context, the current work proposes an alternative strategy to the valorisation of compost, through the production of low-cost materials to be applied in the catalytic wet peroxide oxidation (CWPO) of synthetic wastewater effluents contaminated with caffeine, used as a model pollutant of emerging concern. Caffeine is the most consumed psychoactive drug worldwide. It is one of the components of painkillers, medication against migraine, fatigue, drowsiness and breathing problems. Its consumption is also associated with an overall lower risk of malignant growth like hepatocellular, endometrial or colorectal cancer (Ganzenko et al., 2015). However, the effect of caffeine and its environmental degradation products on aquatic living species is not properly known. Caffeine, is a world wide consumed psychoactive drug, in a way that becomes a persistent compound and cannot be efficiently removed by municipal wastewater treatment facilities (Ganzenko et al., 2015). As a consequence, caffeine and its metabolites are present in the effluents of wastewater treatment plants (Gracia-Lor et al., 2017).This work was financially supported by project “VALORCOMP - Valorización de compost y otros desechos procedentes de la fracción orgánica de los residuos municipales”, 0119_VALORCOMP_2_P, and project “AIProcMat@N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, reference NORTE-01-0145-FEDER-000006, supported by NORTE 2020, under the Portugal 2020 Partnership Agreement, through FEDER, and Project Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio

Some applications of the formalization of the pumping lemma for context-free languages

Context-free languages are highly important in computer language processing technology as well as in formal language theory. The Pumping Lemma for Context-Free Languages states a property that is valid for all context-free languages, which makes it a tool for showing the existence of non-context-free languages. This paper presents a formalization, extending the previously formalized Lemma, of the fact that several well-known languages are not context-free. Moreover, we build on those results to construct a formal proof of the well-known property that context-free languages are not closed under intersection. All the formalization has been mechanized in the Coq proof assistant.- (undefined

Performance And Economic Analysis Of Finished Lambs In Feedlot

This study aimed to evaluate animal performance and economic performance of feedlot crossbred lambs (Santa Inês+ - Suffolk) fed different diets based on hay from Cynodon dactylon genotypes, through the use of financial measures considering only the period of feedlot, without relating it to the complete management cycle. A total of 30 intact crossbred Suffolk lambs, identified with earrings, with an average age of 90 days and an average body weight of 21.5 kg were used in this study. Diets were formulated using as treatments a standard concentrate and hay of the Cynodon dactylon genotypes Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell in a 60:40 forage-to-concentrate ratio. The treatments were distributed in a randomized complete block design with five replicates. There were significant differences between diets in terms of total expenditure on food, and the highest values were obtained for the Jiggs genotype (BRL 48.96/animal). The animals fed diets based on Tifton 68 hay had a higher rate of return (2.16%) and profitability (34.63%) compared to the other diets. The use of diets based on Tifton 68 hay for feedlot lambs in the finishing phase brings higher economic returns compared to the remaining diets.37129330

Synthesis, surface active and antimicrobial properties of new alkyl 2,6-dideoxy-L-arabino-hexopyranosides

Synthesis of alkyl 2,6-dideoxy-L-arabino-hexopyranosides was accomplished by the reaction of 1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol with fatty alcohols in dichloromethane, catalyzed by triphenylphosphine hydrobromide. Reaction with octanol and dodecanol gave the corresponding α-glycosides in 50% and 42% yield, the β-glycosides in 20% and 21% yield and the α-anomer of the Ferrier product in 10% and 9% yield, respectively.Deacetylation of the α-/β-glycosides with sodium methoxide in methanol afforded the amphiphilic L-arabino-hexopyranosides in 94–99% yield. The surface tension at the air–water interface of the octyl L-glycosides and of the dodecyl α-L-glycoside aqueous solutions at 35 °C was measured with a du Noüy ring tensiometer and surface properties such as critical micelle concentration (CMC), relative surface excess, molecular area at the interface and Gibbs micellization free energy were evaluated. The stereochemistry of the hexopyranoside ring in unimers and aggregates is correlated to the hydrophobicity and packing efficiency on the air–water interface. The antibacterial and antifungal activities of the surface-active glycosides were evaluated using the paper disk diffusion method. The dodecyl α-L-arabino-hexopyranoside was quite active over Bacillus cereus and Bacillus subtilis, while low activity was found for this glycoside over Enterococcus faecalis and Listeria monocytogenes. The octyl glycosides tested showed low activity over almost all the above-mentioned bacteria, and also over the fungus Candida albicans. No inhibition of Salmonella enteritidis and of the filamentous fungus Aspergillus niger was detected for any of the compounds tested.info:eu-repo/semantics/publishedVersio

Sugar bislactones by one-step oxidative dimerisation with pyridinium chlorochromate versus regioselective oxidation of vicinal diols

Synthesis of 10-membered bislactones by PCC oxidation of methyl 2,6-di-O-pivaloyl-α-D-glucopyranoside and methyl 4,6-O-benzylidene-α-D-glucopyranoside is described, with emphasis on their structure elucidation using the information gained by combination of NMR spectroscopic techniques with X-ray diffraction data. In alternative, the use of PCC and PCC adsorbed on silica gel or alumina for the regioselective oxidation of vicinal diols in sugars is also reported. Both bislactones showed antifungal activity against Candida albicans, and were slightly active against the bacteria Bacillus subtilis. The bislactone presenting pivaloyl protecting groups also promoted some growth inhibition of Staphylococcus aureus.info:eu-repo/semantics/publishedVersio

Replica Symmetry Breaking Instability in the 2D XY model in a random field

We study the 2D vortex-free XY model in a random field, a model for randomly pinned flux lines in a plane. We construct controlled RG recursion relations which allow for replica symmetry breaking (RSB). The fixed point previously found by Cardy and Ostlund in the glass phase $T<T_c$ is {\it unstable} to RSB. The susceptibility $\chi$ associated to infinitesimal RSB perturbation in the high-temperature phase is found to diverge as $\chi \propto (T-T_c)^{-\gamma}$ when $T \rightarrow T_c^{+}$. This provides analytical evidence that RSB occurs in finite dimensional models. The physical consequences for the glass phase are discussed.Comment: 8 pages, REVTeX, LPTENS-94/2

Entropy and equilibrium state of free market models

Many recent models of trade dynamics use the simple idea of wealth exchanges among economic agents in order to obtain a stable or equilibrium distribution of wealth among the agents. In particular, a plain analogy compares the wealth in a society with the energy in a physical system, and the trade between agents to the energy exchange between molecules during collisions. In physical systems, the energy exchange among molecules leads to a state of equipartition of the energy and to an equilibrium situation where the entropy is a maximum. On the other hand, in the majority of exchange models, the system converges to a very unequal condensed state, where one or a few agents concentrate all the wealth of the society while the wide majority of agents shares zero or almost zero fraction of the wealth. So, in those economic systems a minimum entropy state is attained. We propose here an analytical model where we investigate the effects of a particular class of economic exchanges that minimize the entropy. By solving the model we discuss the conditions that can drive the system to a state of minimum entropy, as well as the mechanisms to recover a kind of equipartition of wealth