Kalanchoe tomentosa: Phytochemical Profiling, and Evaluation of Its Biological Activities In Vitro, In Vivo, and In Silico.

In this work, the leaves of K. tomentosa were macerated with hexane, chloroform, and methanol, respectively. The phytochemical profiles of hexane and chloroform extracts were unveiled using GC/MS, whereas the chemical composition of the methanol extract was analyzed using UPLC/MS/MS. The antibacterial activity of extracts was determined against gram-positive and gram-negative strains through the minimal inhibitory concentration assay, and in silico studies were implemented to analyze the interaction of phytoconstituents with bacterial peptides. The antioxidant property of extracts was assessed by evaluating their capacity to scavenge DPPH, ABTS, and H2O2 radicals. The toxicity of the extracts was recorded against Artemia salina nauplii and Caenorhabditis elegans nematodes. Results demonstrate that the hexane and chloroform extracts contain phytosterols, triterpenes, and fatty acids, whereas the methanol extract possesses glycosidic derivatives of quercetin and kaempferol together with sesquiterpene lactones. The antibacterial performance of extracts against the cultured strains was appraised as weak due to their MIC90 values (>500 µg/mL). As antioxidants, treatment with extracts executed high and moderate antioxidant activities within the range of 50-300 µg/mL. Extracts did not decrease the viability of A. salina, but they exerted a high toxic effect against C. elegans during exposure to treatment. Through in silico modeling, it was recorded that the flavonoids contained in the methanol extract can hamper the interaction of the NAM/NAG peptide, which is of great interest since it determines the formation of the peptide wall of gram-positive bacteria. This study reports for the first time the biological activities and phytochemical content of extracts from K. tomentosa and proposes a possible antibacterial mechanism of glycosidic derivatives of flavonoids against gram-positive bacteria.

Green Synthesis of Silver Nanoparticles with Extracts from Kalanchoe fedtschenkoi: Characterization and Bioactivities.

In this work, the hexane, chloroform, and methanol extracts from Kalanchoe fedtschenkoi were utilized to green-synthesize silver nanoparticles (Kf1-, Kf2-, and Kf3-AgNPs). The Kf1-, Kf2-, and Kf3-AgNPs were characterized by spectroscopy and microscopy techniques. The antibacterial activity of AgNPs was studied against bacteria strains, utilizing the microdilution assay. The DPPH and H2O2 assays were considered to assess the antioxidant activity of AgNPs. The results revealed that Kf1-, Kf2-, and Kf3-AgNPs exhibit an average diameter of 39.9, 111, and 42 nm, respectively. The calculated ζ-potential of Kf1-, Kf2-, and Kf3-AgNPs were -20.5, -10.6, and -7.9 mV, respectively. The UV-vis analysis of the three samples demonstrated characteristic absorption bands within the range of 350-450 nm, which confirmed the formation of AgNPs. The FTIR analysis of AgNPs exhibited a series of bands from 3500 to 750 cm-1, related to the presence of extracts on their surfaces. SEM observations unveiled that Kf1- and Kf2-AgNPs adopted structural arrangements related to nano-popcorns and nanoflowers, whereas Kf3-AgNPs were spherical in shape. It was determined that treatment with Kf1-, Kf2-, and Kf3-AgNPs was demonstrated to inhibit the growth of E. coli, S. aureus, and P. aeruginosa in a dose-dependent manner (50-300 µg/mL). Within the same range, treatment with Kf1-, Kf2-, and Kf3-AgNPs decreased the generation of DPPH (IC50 57.02-2.09 µg/mL) and H2O2 (IC50 3.15-3.45 µg/mL) radicals. This study highlights the importance of using inorganic nanomaterials to improve the biological performance of plant extracts as an efficient nanotechnological approach.

Recent Advances in the Therapeutic Potential of Carotenoids in Preventing and Managing Metabolic Disorders.

Carotenoids constitute compounds of significant biological interest due to their multiple biological activities, such as antimicrobial, anticancer, antiadipogenic, antidiabetic, and antioxidant properties. Metabolic syndrome (MetS) comprehends a series of metabolic abnormalities (e.g., hypertension, obesity, and atherogenic dyslipidemia) that can affect children, adolescents, and the elderly. The treatment of MetS involves numerous medications, which, despite their efficacy, pose challenges due to prolonged use, high costs, and various side effects. Carotenoids and their derivatives have been proposed as alternative treatments to MetS because they reduce serum triglyceride concentrations, promote insulin response, inhibit adipogenesis, and downregulate angiotensin-converting enzyme activity. However, carotenoids are notably sensitive to pH, light exposure, and temperature. This review addresses the activity of carotenoids such as lycopene, lutein, fucoxanthin, astaxanthin, crocin, and ß-carotene towards MetS. It includes a discussion of sources, extraction methods, and characterization techniques for analyzing carotenoids. Encapsulation approaches are critically reviewed as alternatives to prevent degradation and improve the biological performance of carotenoids. A brief overview of the physiopathology and epidemiology of the diseases, including MetS, is also provided.

Enabling the characterization of the nonlinear electrokinetic properties of particles using low voltage.

Insulator-based electrokinetically driven microfluidic devices stimulated with direct current (DC) voltages are an attractive solution for particle separation, concentration, or isolation. However, to design successful particle manipulation protocols, it is mandatory to know the mobilities of electroosmosis, and linear and nonlinear electrophoresis of the microchannel/liquid/particle system. Several techniques exist to characterize the mobilities of electroosmosis and linear electrophoresis. However, only one method to characterize the mobility of nonlinear electrophoresis has been thoroughly assessed, which generally requires DC voltages larger than 1000 V and measuring particle velocity in a straight microchannel. Under such conditions, Joule heating, electrolysis, and the DC power source cost become a concern. Also, measuring particle velocity at high voltages is noisy, limiting characterization quality. Here we present a protocol-tested on 2 µm polystyrene particles-for characterizing the mobility of nonlinear electrophoresis of the liquid/particle system using a DC voltage of only 30 V and visual inspection of particle dynamics in a microchannel featuring insulating obstacles. Multiphysics numerical modelling was used to guide microchannel design and to correlate particle location during an experiment with electric field intensity. The method was validated against the conventional characterization protocol, exhibiting excellent agreement while significantly reducing measurement noise and experimental complexity.

Spatiotemporal hierarchical Bayesian analysis to identify factors associated with COVID-19 in suburban areas in Colombia.

Introduction: The pandemic had a profound impact on the provision of health services in Cúcuta, Colombia where the neighbourhood-level risk of Covid-19 has not been investigated. Identifying the sociodemographic and environmental risk factors of Covid-19 in large cities is key to better estimate its morbidity risk and support health strategies targeting specific suburban areas. This study aims to identify the risk factors associated with the risk of Covid-19 in Cúcuta considering inter -spatial and temporal variations of the disease in the city's neighbourhoods between 2020 and 2022. Methods: Age-adjusted rate of Covid-19 were calculated in each Cúcuta neighbourhood and each quarter between 2020 and 2022. A hierarchical spatial Bayesian model was used to estimate the risk of Covid-19 adjusting for socioenvironmental factors per neighbourhood across the study period. Two spatiotemporal specifications were compared (a nonparametric temporal trend; with and without space-time interaction). The posterior mean of the spatial and spatiotemporal effects was used to map the Covid-19 risk. Results: There were 65,949 Covid-19 cases in the study period with a varying standardized Covid-19 rate that peaked in October-December 2020 and April-June 2021. Both models identified an association of the poverty and stringency indexes, education level and PM10 with Covid-19 although the best fit model with a space-time interaction estimated a strong association with the number of high-traffic roads only. The highest risk of Covid-19 was found in neighbourhoods in west, central, and east Cúcuta. Conclusions: The number of high-traffic roads is the most important risk factor of Covid-19 infection in Cucuta. This indicator of mobility and connectivity overrules other socioenvironmental factors when Bayesian models include a space-time interaction. Bayesian spatial models are important tools to identify significant determinants of Covid-19 and identifying at-risk neighbourhoods in large cities. Further research is needed to establish causal links between these factors and Covid-19.

Divergent Gut Microbiota: Archaeal and Bacterial Signatures Unveil Unique Patterns in Colombian Cyclists Compared to Weightlifters and Non-Athletes.

Engagement in physical activity, across various sports, promotes a diverse microbiota in active individuals. This study examines the gut microbiota of Colombian athletes, specifically weightlifters (n = 16) and road cyclists (n = 13), compared to non-athletes (n = 15). Using Kruskal-Wallis tests, the physical activity level of a group of non-athletic individuals and the sports experience of a group of professional athletes is analyzed. The median age of participants is 24 years, comprising 25 men and 19 women. The microbiota is collected using fecal samples. Participants provided these samples during their pre-competitive stage, specifically during the concentration phase occurring two weeks prior to national competitions. This timing is chosen to capture the microbial composition during a period of heightened physical preparation. Questionnaire responses and microbial composition assessments identify disparities among groups. Microbial composition analysis explores core microbiome, abundance, and taxonomy using Pavian, MicrobiomeAnalyst 2.0, and GraPhlAn. ANCOM-BC2 reveals differentially abundant species. Road cyclists exhibit decreased Bacteria and increased Archaea abundance. Phylum-level variations included Planctomycetes, Acidobacteria, and Proteobacteria, while Bacteroidetes prevailed. Key families influencing gut microbiota are Bacteroidaceae, Muribaculaceae, and Selenomonadaceae. Weightlifters exhibit unique viral and archaeal community connections, while cyclists showed specialized microbial interplay influenced by endurance exercise. Correlation network analysis emphasizes distinctive microbial interactions within athlete groups, shedding light on the impact of physical activities on gut microbiota and athlete health.

Efficacy of powdered alfalfa leaves to ameliorate the toxic effects of aflatoxin B1 in turkey poults.

This experiment was conducted to determine the effect of an adsorbent material based on powdered alfalfa leaves added in the aflatoxin B1 (AFB1)-contaminated diet of turkey poults on production parameters, blood cell count, serum biochemistry, liver enzymes, and liver histology. For this purpose, three hundred and fifty female Nicholas-700 poults were randomly assigned into five treatments: (1) Control, AFB1-free diet; (2) AF, diet contaminated with 250 ng AFB1/g; (3) Alfalfa, AFB1-free diet + 0.5% (w/w) adsorbent; (4) AF+alfalfa, diet contaminated with 250 ng AFB1/g + 0.5% (w/w) adsorbent, and (5) AF+ yeast cell wall (YCW), diet contaminated with 250 ng AFB1/g + 0.5% (w/w) of yeast cell wall (a commercial mycotoxin binder used as reference material). The in vivo efficacy of powdered alfalfa leaves was assessed during a 28-day period. In general, the addition of powdered alfalfa leaves in the AFB1-free diet gave the best performance results (body weight, body weight gain, and feed intake) and improved the values of total protein, glucose, calcium, creatinine, and blood urea nitrogen. Moreover, the addition of powdered alfalfa leaves in the AFB1-contaminated diet enhanced body weight and body weight gain and significantly reduced the feed intake, compared to the AF and AF+YCW groups. Additionally, significant alterations in serum parameters were observed in poults intoxicated with the AFB1, compared to the Control group. Furthermore, typical histopathological lesions were observed in the liver of the AF group, which were significantly ameliorated with the addition of powdered alfalfa leaves. Conclusively, these results pointed out that low inclusion of powdered alfalfa leaves in the contaminated feed counteracted the adverse effects of AFB1 in turkey poults.

The secretome from human-derived mesenchymal stem cells augments the activity of antitumor plant extracts in vitro.

Cancer is understood as a multifactorial disease that involve multiple cell types and phenotypes in the tumor microenvironment (TME). The components of the TME can interact directly or via soluble factors (cytokines, chemokines, growth factors, extracellular vesicles, etc.). Among the cells composing the TME, mesenchymal stem cells (MSCs) appear as a population with debated properties since it has been seen that they can both promote or attenuate tumor progression. For various authors, the main mechanism of interaction of MSCs is through their secretome, the set of molecules secreted into the extracellular milieu, recruiting, and influencing the behavior of other cells in inflammatory environments where they normally reside, such as wounds and tumors. Natural products have been studied as possible cancer treatments, appealing to synergisms between the molecules in their composition; thus, extracts obtained from Petiveria alliacea (Anamu-SC) and Caesalpinia spinosa (P2Et) have been produced and studied previously on different models, showing promising results. The effect of plant extracts on the MSC secretome has been poorly studied, especially in the context of the TME. Here, we studied the effect of Anamu-SC and P2Et extracts in the human adipose-derived MSC (hAMSC)-tumor cell interaction as a TME model. We also investigated the influence of the hAMSC secretome, in combination with these natural products, on tumor cell hallmarks such as viability, clonogenicity, and migration. In addition, hAMSC gene expression and protein synthesis were evaluated for some key factors in tumor progression in the presence of the extracts by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Multiplex, respectively. It was found that the presence of the hAMSC secretome did not affect the cytotoxic or clonogenicity-reducing activities of the natural extracts on cancer cells, and even this secretome can inhibit the migration of these tumor cells, in addition to the fact that the profile of molecules can be modified by natural products. Overall, our findings demonstrate that hAMSC secretome participation in TME interactions can favor the antitumor activities of natural products.

Site percolation threshold of composite square lattices and its agroecology applications.

We analyze the percolation threshold of square lattices comprising a combination of sites with regular and extended neighborhoods. We found that the percolation threshold of these composed systems smoothly decreases with the fraction of sites with extended neighbors. This behavior can be well-fitted by a Tsallis q-Exponential function. We found a relation between the fitting parameters and the differences in the gyration radius among neighborhoods. We also compared the percolation threshold with the critical susceptibility of nearest and next-to-nearest neighbor monoculture plantations vulnerable to the spread of phytopathogen. Notably, the critical susceptibility in monoculture plantations can be described as a linear combination of two composite systems. These results allow the refinement of mathematical models of phytopathogen propagation in agroecology. In turn, this improvement facilitates the implementation of more efficient computational simulations of agricultural epidemiology that are instrumental in testing and formulating control strategies.

Trends and challenges in microfluidic methods for protein manipulation-A review.

Proteins are important molecules involved in an immensely large number of biological processes. Being capable of manipulating proteins is critical for developing reliable and affordable techniques to analyze and/or detect them. Such techniques would enable the production of therapeutic agents for the treatment of diseases or other biotechnological applications (e.g., bioreactors or biocatalysis). Microfluidic technology represents a potential solution to protein manipulation challenges because of the diverse phenomena that can be exploited to achieve micro- and nanoparticle manipulation. In this review, we discuss recent contributions made in the field of protein manipulation in microfluidic systems using different physicochemical principles and techniques, some of which are miniaturized versions of already established macro-scale techniques.

Epoxide of diosgenin acetate synthesis: DoE for diastereoselective yield optimization, antimicroibial, antioxidant and antiproliferative effects.

Diosgenin and its derivatives have proved a huge importance in diverse biological activities. The optimized production of the diastereoisomers of the epoxide of diosgenin acetate by means of mCPBA is reported herein. This transformation had a previous design of experiments using the application of a statistical factorial DoE of 4 parameters (nk), where one variable is varied at a time, while others stay constant. The temperature showed the greatest effect on the reaction yield; so, at 298 K the diastereomeric ratio 3:1 of α and ß-epoxides, normally found, was raised to 1:1. Time was the second significant variable, but due to its high correlation with temperature, 30 min were required for a global 90% conversion at least. These diastereoisomers were characterized both isolated and in the mixtures obtained, to determine their antioxidant, antimicrobial and antiproliferative activity, finding a low antioxidant capacity by DPPH, but antimicrobial activity at the level of penicillin in gram negative bacteria by 1ß better to 1α. The antiproliferative capacity was higher for diastereoisomer ß, agreeing with the proportion of the mixture obtained by different conditions, increasing this in relation to the amount of this diastereoisomer present in hormone-dependent cancer cell lines such as Hela, PC-3 and MCF-7, with 10.0 µM obtained values of viability at 21.8 %, 35.8 % and 12.3 % respectively. DoE optimization allows to manipulate the ratio between diastereoisomers with the minimum number of experiments, extending the analysis of the effect of the ratio between diastereoisomers and the in silico potential as well as the biological activity.

Use of audiovisual devices in transnasal endoscopy without sedation to improve tolerance. A prospective clinical trial.

INTRODUCTION AND AIM: Transnasal endoscopy (TNE) has proven its diagnostic utility, but it has not been widely accepted given that it is performed without sedation. There are no previous studies on the use of methods to improve its tolerability. Our aim was to evaluate the tolerability of TNE, when simultaneously performed with an audiovisual device as a distractor. METHODS: We evaluated 50 patients, 10 of whom did not agree to participate. The performance of the procedure was explained, using an audiovisual device. Before randomization, we applied anxiety and depression scores. Patients were divided into 2 groups: Group I (using an audiovisual device during the procedure) and Group II (without a device). Anxiety and numeric pain rating scales were used, and vital signs were monitored and recorded before, during, and after the endoscopy. An overall procedure satisfaction score was applied at the end of the study and 24 h later. RESULTS: Mean age was 41.6 years and 35 of the patients were women (87.5%). The most frequent indication for TNE was refractory gastroesophageal reflux disease. There were no severe comorbidities, and none of the patients had a significant anxiety or depression score. One patient in Group II did not tolerate TNE due to nasal pain. There was no statistically significant difference between groups, regarding anxiety, pain, vital signs, and satisfaction scale. CONCLUSION: Our study showed that TNE was well tolerated and had a high acceptance rate in our patients. The use of distracting audiovisual devices did not increase tolerance to the endoscopic procedure.

Using Machine Learning Algorithms on Electroencephalographic Signals to Assess Engineering Students' Focus While Solving Math Exercises / Uso de Algoritmos de Aprendizaje Automático en Señales Electroencefalográficas para Evaluar la Concentración de Estudiantes de Ingeniería al Resolver Ejercicios Matemáticos

Abstract In this paper, we present an attention classification method using Machine-Learning Algorithms. The EEG signals were recorded from ten engineering students with an EPOC+BCI using the electrodes F3, F4, P7, and P8 while solving some mathematical operations. The recording time for these activities is around 20 minutes. Next, a similar time EEG register is obtained while doing non-academic activities, such as chattering with the staff, checking cell phones, or playing a video game. With these EEG registers, we obtained a set of features to train and evaluate attention using Machine Learning algorithms. This research shows how engineering students interact with math topics in solving mental operations and complex reasoning by increasing brain domain and knowledge for mathematical reasoningrelated processes, such as sustained and shifting attention and logical constructions for object interaction during operations resolution. The Random Forest algorithm (RF) obtained the highest accuracy with 0.7392, an F1 Score of 0.7430, and the highest Specificity/Accuracy with 0.7261.

Resumen Se presenta un método de clasificación de la atención utilizando algoritmos de aprendizaje automático. Con las señales EEG de diez estudiantes de ingeniería adquiridas utilizando los electrodos F3, F4, P7 y P8 de una BCI EPOC+ mientras resuelven productos escalares, multiplicaciones algebraicas simples, simplificaciones e integrales por aproximadamente 20 minutos. Posteriormente, se obtiene un registro EEG de tiempo similar mientras se realizan actividades no académicas, como charlar con el personal, consultar el móvil o jugar a un videojuego. Se obtienen algunas características/parámetros, se entrenan y evalúan varios algoritmos de aprendizaje automático para la clasificación de la atención. Los resultados de esta investigación pueden mejorar la forma en que los estudiantes de ingeniería interactúan con los temas matemáticos en la resolución de operaciones mentales y razonamientos complejos, aumentando el dominio y el conocimiento cerebral para los procesos relacionados con el razonamiento matemático, como la atención sostenida y cambiante y las construcciones lógicas para la interacción con objetos durante la resolución de operaciones. El clasificador Random Forest obtuvo la mayor precisión con 0.7392, una puntuación F1 de 0.7430 y la mayor especificidad/precisión con 0.7261.

A fractal scaling analysis of the SARS-CoV-2 genome sequence.

An approach based on fractal scaling analysis to characterize the organization of the SARS-CoV-2 genome sequence was used. The method is based on the detrended fluctuation analysis (DFA) implemented on a sliding window scheme to detect variations of long-range correlations over the genome sequence regions. The nucleotides sequence is mapped in a numerical sequence by using four different assignation rules: amino-keto, purine-pyrimidine, hydrogen-bond and hydrophobicity patterns. The originally reported sequence from Wuhan isolates (Wuhan Hu-1) was considered as a reference to contrast the structure of the 2002-2004 SARS-CoV-1 strain. Long-range correlations, quantified in terms of a scaling exponent, depended on both the mapping rule and the sequence region. Deviations from randomness were attributed to serial correlations or anti-correlations, which can be ascribed to ordered regions of the genome sequence. It was found that the Wuhan Hu-1 sequence was more random than the SARS-CoV-1 sequence, which suggests that the SARS-CoV-2 possesses a more efficient genomic structure for replication and infection. In general, the virus isolated in the early 2020 months showed slight correlation differences with the Wuhan Hu-1 sequence. However, early isolates from India and Italy presented visible differences that led to a more ordered sequence organization. It is apparent that the increased sequence order, particularly in the spike region, endowed some early variants with a more efficient mechanism to spreading, replicating and infecting. Overall, the results showed that the DFA provides a suitable framework to assess long-term correlations hidden in the internal organization of the SARS-CoV-2 genome sequence.

Síntomas depresivos, ansiosos e insomnio, y posibles factores asociados en personal de salud, en un Hospital General en Suramérica, durante la pandemia por COVID-19 en 2020 / Depressive and anxious symptoms and insomnia, and possible associated factors in health workers, in a General Hospital in South America, during the COVID-19 pandemic in 2020

La pandemia por el nuevo coronavirus COVID- 19 ha tenido impacto en la salud mental del personal médico y de enfermería en todo el mundo. Objetivo: identificar la frecuencia de síntomas depresivos, ansiosos e insomnio y los factores posiblemente relacionados con estos desenlaces en el personal sanitario de un hospital de Suramérica durante el primer pico de la pandemia. Materiales y métodos: se aplicaron las escalas PHQ-9 para depresión, GAD- 7 para ansiedad, ISI - 7 para insomnio en 876 trabajadores de la salud del Hospital Pablo Tobón Uribe en la ciudad de Medellín. Resultados: de los 876 participantes (29,2% médicos, 21.2% profesionales de enfermería y 49,5% auxiliares de enfermería), 357 (40.8%) presentaron síntomas depresivos, 300 (34.2%) síntomas ansiosos y 317 (36.2%) insomnio. Se observaron síntomas de depresión, ansiedad e insomnio, con mayor frecuencia en quienes no tenían las necesidades básicas satisfechas y en quienes se sentían estigmatizados por ser personal de salud. Además, la depresión se presentó con más frecuencia en mujeres, la ansiedad en menores de 44 años y el insomnio en personas separadas. Conclusiones: la frecuencia de problemas de salud mental en el personal de salud es considerable. Estos hallazgos demuestran la necesidad de atención en la salud mental de los profesionales médicos y de enfermería durante la pandemia por COVID-19 y la búsqueda de estrategias para mitigar el riesgo en esta población.

Background: pandemic due to novel coronavirus COVID-19 has impacted on the mental health of health care workers all around the world. Material and Methods: this is a cross sectional study in which questionnaires PHQ-9 for depression, GAD-7 for anxiety, ISI-7 for insomnia were virtually and self administered by 876 health care workers laboring in hospital Pablo Tobón Uribe in Medellin city. Results: from 876 participants (29.2% physicians, 21.2% nurses and 49.5% technical nurses), 357 (40.8%) developed depressive symptoms, 300 (34.2%) anxious symptoms and 317 (36.2%) insomnia. Symptoms of depression, anxiety and insomnia were more frequently found in those who did not have basic needs satisfied and in those who felt stigmatized due to being health personal. Besides, depressive symptoms were more frequent in women, anxious symptoms in people younger than 44 years old and insomnia in divorced people. Conclusions: the frequency of mental health problems in health care workers is significant, these findings bring to light the needs for mental health attention in nurses and doctors during COVID-19 pandemic and the research of strategies to mitigate the risk on this population. Feeling stigmatized and not having basic needs satisfied were associated with symptoms of anxiety, depression and insomnia.

Biocatalyst developed with recovered iron-rich minerals enhances the biotransformation of SARS-CoV-2 antiviral drugs in anaerobic bioreactors.

The biotransformation of the SARS-CoV-2 antiviral drugs, ribavirin and tenofovir, was studied in methanogenic bioreactors. The role of iron-rich minerals, recovered from a metallurgic effluent, on the biotransformation process was also assessed. Enrichment of anaerobic sludge with recovered minerals promoted superior removal efficiency for both antivirals (97.4 % and 94.7 % for ribavirin and tenofovir, respectively) as compared to the control bioreactor lacking minerals, which achieved 58.5 % and 37.9 % removal for the same drugs, respectively. Further analysis conducted by liquid chromatography coupled to mass spectroscopy revealed several metabolites derived from the biotransformation of both antivirals. Interestingly, tracer analysis with 13CH4 revealed that anaerobic methane oxidation coupled to Fe(III) reduction occurred in the enriched bioreactor, which was reflected in a lower content of methane in the biogas produced from this system, as compared to the control bioreactor. This treatment proposal is suitable within the circular economy concept, in which recovered metals from an industrial wastewater are applied in bioreactors to create a biocatalyst for promoting the biotransformation of emerging pollutants. This strategy may be appropriate for the anaerobic treatment of wastewaters originated from hospitals, as well as from the pharmaceutical and chemical sectors.

Analysis of starch digestograms using Monte Carlo simulations.

Monte Carlo dynamics were used to simulate the enzymatic starch digestion. Enzyme and starch molecules were distributed on a periodic grid and allowed to stochastically interact according to the kinetics scheme S + E â†’ P + E. Digestion of gelatinized dispersions was simulated by assuming limited mobility of starch and complete mobility of enzymes and products. The results showed that the starch conversion kinetics follows the exponential model X(t) = X∞(1 -  exp (-kHt)). On the other hand, the simulation of native granular starch digestion considered non-mobile aggregates of starch molecules hydrolyzed to products by mobile enzyme molecules. The results showed the presence of bi-phasic digestion patterns, which were linked to the transition from a regular to an irregular (fractal-like) granule morphology as a consequence of the erosion of the granule surface by the enzyme action. The simulation results were contrasted qualitatively with experimental results for gelatinized and granular starch digestion.