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The influence of residual cuts on the deactivation of hierarchical Y zeolite-based catalysts during the co-processing of vacuum gas oil (VGO) with atmospheric residue (ATR) was investigated. The experiments were conducted in a laboratory-scale MAT-type reactor. The conversion of VGO, ATR, and their 70:30 (mass basis) mixture was examined using two composite catalysts: Cat.Y.0.00 and Cat.Y.0.20. The operating conditions closely resembled those of the commercial catalytic cracking process (550 °C and contact times of 10 to 50 s). When ATR was processed individually, the conversion remained below 50 wt%. However, significant improvements in conversion rates were achieved and catalyst deactivation was mitigated when ATR was co-processed with VGO. Notably, the BET surface area and average mesopore volume were adversely impacted by ATR, which also led to the accumulation of high levels of metals and nitrogen on the spent catalyst, detrimentally affecting its acidic and structural properties. Moreover, substantial coke deposition occurred during ATR cracking. The soluble and insoluble coke analysis revealed H/C ratio values of up to 0.36, indicative of polycondensed coke structures with more than ten aromatic rings. The nature of the coke was confirmed through TPO and FTIR analyses. Interestingly, the CatY.0.20 catalyst exhibited less activity loss, retaining superior acid and structural properties. Co-processing Colombian atmospheric residue with ATR loadings of 30 wt% (higher than the typical 20 wt%) in catalysts formulated with hierarchical zeolites presents a promising alternative for commercial applications. This research opens avenues for optimizing catalytic cracking processes.

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This study investigated the deactivation and regeneration of hierarchical zeolites in vacuum gas oil conversion, aiming to reach the equilibrium state seen in fluidized bed catalytic cracking (FCC). The research utilized various characterization techniques to analyze the properties of zeolites before and after coking and regeneration. Zeolite Y-0.20-S was found to have the highest gasoline selectivity and quality, mirroring industrial yields, and displayed notable stability across deactivation/regeneration cycles. Higher mesopore concentration in zeolites led to increased coke selectivity and better resistance to deactivation. The study observed a dominance of aromatic coke with a higher degree of condensation in these zeolites. Despite coke deposition affecting acid and textural properties, the regeneration process effectively restored these characteristics, proving its efficiency. The zeolites with greater mesoporosity retained their fundamental properties responsible for activity and selectivity, highlighting the importance of selecting materials that provide high conversions and maintain stability and product selectivity over multiple cycles. The Y-0.20-S zeolite, in particular, was identified as a promising candidate for commercial catalyst development for gasoline production, contributing to the FCC process's energy efficiency.

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The photophysical relaxation mechanisms of 1-cyclohexyluracil, in vacuum and water, were investigated by employing the Multi-State CASPT2 (MS-CASPT2, Multi-State Complete Active-Space Second-Order Perturbation Theory) quantum chemical method and Dunning's cc-pVDZ basis sets. In both environments, our results suggest that the primary photophysical event is the population of the S11(ππ*) bright state. Afterwards, two likely deactivation pathways can take place, which is sustained by linear interpolation in internal coordinates defined via Z-Matrix scans connecting the most important characteristic points. The first one (Route 1) is the same relaxation mechanism observed for uracil, its canonical analogue, i.e., internal conversion to the ground state through an ethylenic-like conical intersection. The other route (Route 2) is the direct population transfer from the S11(ππ*) bright state to the T23(nπ*) triplet state via an intersystem crossing process involving the (S11(ππ*)/T23(nπ*))STCP singlet-triplet crossing point. As the spin-orbit coupling is not too large in either environment, we propose that most of the electronic population initially on the S11(ππ*) state returns to the ground following the same ultrafast deactivation mechanism observed in uracil (Route 1), while a smaller percentage goes to the triplet manifold. The presence of a minimum on the S11(ππ*) potential energy hypersurface in water can help to understand why experimentally it is noticed suppression of the triplet states population in polar protic solvent.

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Designing an economically viable catalyst that maintains high catalytic activity and stability is the key to unlock dry reforming of methane (DRM) as a primary strategy for biogas valorization. Ni/Al2O3 catalysts have been widely used for this purpose; however, several modifications have been reported in the last years in order to prevent coke deposition and deactivation of the samples. Modification of the acidity of the support and the addition of noble metal promoters are between the most reported strategies. Nevertheless, in the task of designing an active and stable catalyst for DRM, the selection of an appropriate noble metal promoter is turning more challenging owing to the lack of homogeneity of the different studies. Therefore, this research aims to compare Ru (0.50 and 2.0%) and Re (0.50 and 2.0%) as noble metal promoters for a Ni/MgAl2O4 catalyst under the same synthesis and reaction conditions. Catalysts were characterized by XRF, BET, XRD, TPR, hydrogen chemisorption (H2-TPD), and dry reforming reaction tests. Results show that both promoters increase Ni reducibility and dispersion. However, Ru seems a better promoter for DRM since 0.50% of Ru increases the catalytic activity in 10% and leads to less coke deposition.

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This study investigated the influence of cation type on the sodium deactivation of Brazilian bentonite varieties. Four bentonite clays were studied, including three mixed-cationic and one magnesium. Swelling and the main exchangeable cations (Na+, K+, Mg2+ and Ca2+) were the main evaluation parameters in this study. Periodic washes of the sodium-activated bentonites were performed based on the hypothesis that a possible desorption of the cations (primarily Na+) could cause the deactivation. Sodium activation was monitored using XRD measurements and an increase in swelling. Sodium deactivation was observed and monitored via a decrease in swelling. Positive and negative effects, caused by the proportions of the cations and the dominance of Mg2+, were emphasized by the set of cationically different samples applied in this study, which helped to answer the influence of main exchangeable cations, specially Mg2+, on the deactivation process.

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Cellulase and hemicellulase activities in a 1:1 ratio of enzymes extracted from Chrysoporthe cubensis and Penicillium pinophilum were evaluated in the presence of known monocomponent phenolic inhibitors and also with phenol mixtures derived from alkali pretreated sugarcane bagasse. The cellulolytic activities from C. cubensis:P. pinophilum displayed a much higher tolerance to phenolic inhibitors than equivalent enzyme activities obtained from Trichoderma reesei and Aspergillus niger. Enzymes from T. reesei and A. niger were deactivated at 0.3 and 1.5mg phenols/mg protein, respectively, as reported previously, while enzymes from C. cubensis:P. pinophilum resisted deactivation at 35mg phenols/mg protein. However, tolerance of xylanase with respect to phenols required the presence of laccase. Removal of laccase (enzyme) activity using sodium azide resulted in a 2x higher xylanase deactivation (from 40% to 80%). This paper identifies enzymes that are phenol tolerant, and whose adoption for lignocellulose hydrolysis could contribute to reductions in enzyme loading needed to hydrolyze alkali pretreated lignocellulosic substrates in the presence of lignin derived phenols.

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Tomando dois casos clínicos como eixo condutor, discute-se a relação necessária entre processos de adoecimento psíquico e estratégias terapêuticas. O primeiro caso se caracteriza por um psiquismo tomado pelo barulho do embate ininterrupto com seu objeto interno/externo; o segundo, pelo silêncio de um mundo interno desertificado. A compreensão dos respectivos processos de adoecimento determina duas estratégias terapêuticas distintas: desativação do binômio angústia-defesa no primeiro caso e revitalização psíquica no segundo.

By building this paper upon two clinical vignettes, the author discusses the necessary relationship between the psychopathological processes and therapeutic strategies. The first case is characterized by a psyche that is taken by the noise of an uninterrupted collision with its internal/external object. The other case is characterized by the silence of an inner world that becomes desert. Understanding these cases and their respective psychopathological processes defines two different therapeutic strategies: deactivation of the anxiety-defense binomial (i.e., anxietydefense mechanisms) in the first case, and psychic revitalization in the second case.

Tomando dos casos como eje conductor, la autora analiza la relación necesaria entre los procesos psicopatológicos y la especificidad de las estrategias terapéuticas. El primer caso se caracteriza por una psique tomada por el ruido de la lucha ininterrumpida con su objeto interno/ externo; el segundo, por el silencio de un mundo interno desertificado. La comprensión de los procesos psicopatológicos determina las estrategias terapéuticas necesarias: la desactivación del binomio angustia-defensa en el primer caso, y la revitalización psíquica en el segundo.

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The aim of this research was the partial characterization of polygalacturonase (PG) extracts produced by a newly isolated Penicillium brasilianum and Aspergillus niger in submerged fermentation. The partial characterization of the crude enzymatic extracts showed optimum activity at pH 5.5 and 37 °C for both extracts. The results of temperature stability showed that PG from both microorganisms were more stable at 55 °C. However, the enzyme obtained by P. brasilianum presents a half-life time (t 1/2 = 693.10 h), about one order of magnitude higher than those observed in for A. niger at 55 °C. In terms of pH stability, the PG produced by P. brasilianum presented higher stability at pH 4.0 and 5.0, while the PG from A. niger showed higher stability at pH 5.0.

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Repetitive Magnetic Stimulation (rTMS) has shown to modify the excitability of targeted cortical regions in animals and humans, thus transiently altering the efficiency of neural projections within extended brain networks. Adequate processing and behavioral output depend on a given ‘state’ of functional interactions between cortical and subcortical nodes within this network. We applied rTMS trains targeted at the visuoparietal (VP) cortex, which is a crucial cortical node of an extended visuo-spatial neural network, in both, intact (n=2) and injured cats (n=2) with unilateral ablation of the VP region. All four intact cats were intensively trained in a set of visuo-spatial tasks consisting in the detection and localization of moving or static targets. In two of these cats, a 50 mm circular coil was centered on the left VP cortex and Sham or real rTMS was delivered during 20 minutes at 1 Hz. Real but not Sham rTMS significantly increased the number of errors in orienting responses towards static but not moving targets, presented at the contralateral visual hemifield (38±4%; and 48±3% p<0.05 vs. pre rTMS), whereas no increase respect to baseline was observed for ipsilateral targets (5±2%; 2±1%; n.s). Performance went back to baseline error levels 45 minutes after the end of the stimulation (4±2; 6±1%). In 2 other animals, the right or left parietal and primary visual cortex was surgically removed, generating a Daily stimulation with 1 Hz rTMS on the intact VP region resulted in a progressive reduction of detection¬orienting mistakes to moving but not static stimuli (down to 34±5% and 28±4% errors; p<0.05). We conclude that rTMS is able to interact with brain networks in both ways, transiently disrupting visuo-spatial processing in normal animals, and also canceling spatial neglect generated by lesions of the same areas. It constitutes, thus, a non-invasive ‘surgery-less’ method to manipulate brain activity and promote recovery after injuries.

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