Exploring anti-diabetic potential of compounds from roots of Dendrobium polyanthum Wall. ex Lindl. through inhibition of carbohydrate-digesting enzymes and glycation inhibitory activity.

Eight compounds, including one anthraquinone, two bibenzyls, one phenanthrene, three dihydrophenanthrenes, and one flavonoid, were isolated from the roots of Dendrobium polyanthum Wall. ex Lindl. Among these, six compounds were investigated for inhibitory activities against alpha-glucosidase, alpha-amylase, and advanced glycation end products (AGEs) production. Additionally, molecular docking was conducted to analyze the interactions of the test compounds with alpha-glucosidase. Moscatin, the only isolated phenanthrene, displayed the strongest anti-alpha-glucosidase activity with an IC50 of 32.45 ± 1.04 µM, approximately 10-fold smaller than that of acarbose. Furthermore, moscatilin most strongly inhibited alpha-amylase and AGEs production with IC50 values of 256.94 ± 9.87 and 67.89 ± 9.42 µM, respectively. Molecular docking analysis revealed the effective binding of all substances to alpha-glucosidase with smaller lowest binding energy values than acarbose. Moscatin was selected for kinetics studies, and it was identified as a non-competitive inhibitor with approximately 9-fold greater inhibitory capability than acarbose. This study represents the first report on the phytochemical constituents and antidiabetic potential of compounds derived from the roots of D. polyanthum Wall. ex Lindl.

CH4 production potential of autotrophic nitrification bacteria produced in the submerged nitrification bioreactor in the laboratory and kinetic analysis.

In this study, CH4 production capacity of nitrification bacteria (NB) obtained from the submerged biofilter in the laboratory was investigated. Biochemical methane potential (BMP) test was carried out with the NB amount of zero (control, CR), 5% (R1), 10% (R2), and 15% (R3) at a temperature of about 37 ± 0.5°C. Compared to the CR, significantly higher cumulative CH4 volume of about 290, 490, and 715 mL were determined in the R1, R2, and R3, respectively. All the applied kinetic models gave good results (R2 ≥0.97), while the Transference Function and First-order models provided the better R2 values. The delay phase (λ) was not observed in the AD process, and CH4 production started immediately on the first day of operation. The predicted k value of 0.133 day-1 was high in CR, while it was approximately between 0.078 and 0.112 day-1 for the higher amount of NB containing BMP units, which indicated that the AD required long reaction time.

Co-Extraction of Aluminum and Silicon and Kinetics Analysis in Carbochlorination Process of Low-Grade Bauxite.

Addressing the issue that the Bayer process is not suitable for low-grade bauxite, carbochlorination was proposed to recover aluminum and silicon from low-grade bauxite. This study focused on the behavior of aluminum and silicon during the carbochlorination process of low-grade bauxite. The impact of various process parameters on the chlorination efficiency was investigated, and the chlorination mechanism and kinetics of aluminum and silicon chlorination in bauxite were analyzed and discussed. Under optimal experimental conditions, the chlorination efficiency of Al2O3 and SiO2 reached 94.93% and 86.32%, respectively. The carbochlorination of aluminum and silicon in bauxite adhered to a shrinking, unreacted core model governed by gas diffusion within the product layer. This process can be bifurcated into two stages. Additionally, calculations were conducted to determine the apparent activation energy and reaction order of the chlorination processes involving Al2O3 and SiO2. Examining the chlorination mechanism revealed that the bauxite carbochlorination encompasses transformations among various minerals. Notably, the aluminum component prefers to participate in the carbothermal chlorination reaction over silicon.

Kinetic Insights into the Antioxidant Effect of Isatin-Thiosemicarbazone in Biodiesel Blends.

Biodiesel has several drawbacks, such as being prone to oxidation, having reduced stability, and having limited storage time. Antioxidants compatible with biodiesel are being used to address its drawbacks. Utilizing antioxidants effectively improves the quality of biodiesel. Enhancing the quality of biodiesel for use as a clean energy source benefits both the global economy and ecology. Therefore, we believe that our work will contribute to the advancement of the biodiesel industry worldwide. This study used blends consisting of 20% biodiesel and 80% diesel fuel. Isatin-thiosemicarbazones were tested as additives in blends at a concentration of 3000 parts per million (ppm) using an oxifast device and were compared with the chemical antioxidant Trolox. FT-IR, DSC, and TGA were used to characterize these samples. DSC measured sample crystallization temperatures (Tc). Samples with antioxidants showed decreased values compared to the non-antioxidant diesel sample D100. Several DSC tests were conducted to determine the antioxidant strengths of various samples. The results show that the FT-IR spectrum's antioxidant effect regions grow clearer with antioxidants. The extra antioxidant is effective. Biodiesel's oxidative stability improves with isatin-thiosemicarbazones at varying concentrations. The kinetics of thermal decomposition of isatin-thiosemicarbazones under non-isothermal conditions were determined using the Kissinger, Ozawa, and Boswell techniques. The activation energies of compounds 1 and 2 were calculated as 137-147 kJ mol-1 and 173-183 kJ mol-1, respectively.

Synthesis of bis(2-aminoethyl)amine functionalized mesoporous silica (SBA-15) adsorbent for selective adsorption of Pb2+ ions from wastewater.

Rapid growth in the industry has released large quantities of contaminants, particularly metal discharges into the environment. Heavy metal poisoning in water bodies has become a major problem due to its toxicity to living organisms. In this study, we developed a 3-chloropropyl triethoxysilane incorporated mesoporous silica nanoparticle (SBA-15) based adsorbent utilizing the sol-gel process and Pluronic 123 (P123) as a structure-directing surfactant. Furthermore, the produced SBA-15 NPs were functionalized with bis(2-aminoethyl)amine (BDA) using the surface grafting approach. The physical and chemical properties of the prepared SBA-15@BDA NPs were determined using a variety of instruments, including small-angle X-ray diffraction (SAXS), Fourier-transform infrared (FTIR), scanning electron microscope (SEM), N2 adsorption-desorption, thermogravimetric, particle size distribution, and zeta potential analysis. The MSN has a large surface area of up to 574 m2/g, a pore volume of 0.57 cm3/g, and a well-ordered mesoporous nanostructure with an average pore size of 3.6 nm. The produced SBA-15@BDA NPs were used to adsorb selectively to lead (Pd2+) ions from an aqueous solution. The adsorption study was performed under various conditions, including the influence of solution pH, adsorbent dose, adsorption kinetics, adsorption selectivity in the presence of competing metal ions, and reusability. The results of the kinetic study demonstrated that SBA-15@BDA NPs absorb selectively Pb2+ ions via chemisorption. The SBA-15@BDA NPs show Pb2+ ions with a maximum adsorption capacity of ~ 88% and an adsorbed quantity of approximately ~ 112 mg/g from the studied aqueous solution. The adsorption mechanism relies on coordination bonding between Pb2+ ions and surface-functionalized amine groups on SBA-15@BDA NPs. Furthermore, the proposed SBA-15@BDA NPs adsorbent demonstrated excellent reusability over five cycles without significantly reducing adsorption performance. As a consequence, SBA-15@BDA NPs might serve as an effective adsorbent for the selective removal of Pb2+ ions from aqueous effluent.

The influence of drying methods on extract content, tyrosinase activity inhibition, and mechanism in Ascophyllum nodosum: A combined microstructural and kinetic study.

This study evaluates vacuum drying (VD), microwave drying (MD), hot air drying (HAD), and freeze drying (FD), on the color and microstructure changes of Ascophyllum nodosum (A. nodosum), which affect the extraction of polyphenols and flavonoids. During drying, VD and FD show slight color change and looser structure, aiding in active compound preservation and extraction. Polyphenols extracted from A. nodosum (PEAn) using these methods show higher anti-tyrosinase activity, with VD treatment exhibiting the strongest inhibition. Kinetic studies demonstrate competitive inhibition between PEAn and tyrosinase. The binding constant (Ki) values indicate that PEAn treated with VD exhibits the most effective inhibition on tyrosinase, and the Zeta potential suggests the formation of the most stable complex. Circular dichroism (CD) spectroscopy shows significant enzyme rearrangement with VD-treated PEAn. Molecular docking confirms strong binding affinity. This study aims to enhance the utility of A. nodosum and develop novel uses for tyrosinase inhibitors in food.

Optimizing bio-vanillin synthesis from ferulic acid via Pediococcus acidilactici: A systematic approach to process enhancement and yield maximization.

The use of lignocellulosic biomass to create natural flavor has drawn attention from researchers. A key flavoring ingredient that is frequently utilized in the food industry is vanillin. In this present study, Pediococcus acidilactici PA VIT effectively involved in the production of bio-vanillin by using Ferulic acid as an intermediate with a yield of 11.43 µg/mL. The bio-vanillin produced by Pediococcus acidilactici PA VIT was examined using FTIR, XRD, HPLC, and SEM techniques. These characterizations exhibited a unique fingerprinting signature like that of standard vanillin. Additionally, the one variable at a time method, placket Burmann method, and response surface approach, were employed to optimize bio-vanillin. Based on the central composite rotary design, the most important process factors were determined such as agitation speed, substrate concentration, and inoculum size. After optimization, bio-vanillin was found to have tenfold increase, with a maximum yield of 376.4 µg/mL obtained using the response surface approach. The kinetic study was performed to analyze rate of reaction and effect of metal ions in the production of bio-vanillin showing Km of 10.25, and Vmax of 1250 were required for the reaction. The metal ions that enhance the yield of bio-vanillin are Ca2+, k+, and Mg2+ and the metal ions that affects the yield of bio-vanillin are Pb+ and Cr+ were identified from the effect of metal ions in the bio-vanillin production.

Using NaOH@Graphene oxide-Fe3O4 as a magnetic heterogeneous catalyst for ultrasonic transesterification; experimental and modelling.

Burning fossil fuels causes toxic gas emissions to increase, therefore, scientists are trying to find alternative green fuels. One of the important alternative fuels is biodiesel. However, using eco-friendly primary materials is a main factor. Sustainable catalysts should have high performance, good activity, easy separation from reaction cells, and regenerability. In this study, to solve the mentioned problem NaOH@Graphene oxide-Fe3O4 as a magnetic catalyst was used for the first time to generate biodiesel from waste cooking oil. The crystal structure, functional groups, surface area and morphology of catalyst were studied by XRD, FTIR, BET, and FESEM techniques. The response surface methodology based central composite design (RSM-CCD) was used for biodiesel production via ultrasonic technique. The maximum biodiesel yield was 95.88% in the following operation: 10.52:1 molar ratio of methanol to oil, a catalyst weight of 3.76 wt%, a voltage of 49.58 kHz, and a time of 33.29 min. The physiochemical characterization of biodiesel was based to ASTM standard. The magnetic catalyst was high standstill to free fatty acid due to the five cycle's regeneration. The kinetic study results possess good agreement with first-order kinetics as well as the activation energy and Arrhenius constant are 49.2 kJ/min and 16.47 * 1010 min-1, respectively.

Enhanced fluoride removal using montmorillonite clay modified with CoFe2O4 and metal-organic frameworks.

The use of modified clays can play an effective role as an effective adsorbent in removing fluoride (Flu) ions from water and aqueous solutions. In the present research, montmorillonite clay (MMt) was modified using CoFe2O4 magnetic particles and Al-Fe fumarate metal-organic framework (Al-Fe Fum) and was utilized as an efficient adsorbent for removing Flu from aqueous solution. The properties of MMt and MMt/CoFe2O4/Al-Fe Fum samples were investigated using different techniques. The results showed that with the modification of MMt using CoFe2O4 magnetic particles and the metal-organic framework of Al-Fe Fum, the BET surface has increased notably from 13.217 to 365.80 m2/g. To investigate the effect of independent variables and their interaction on the efficiency of the Flu adsorption, response surface method-central compound design (RSM-CCD) was served. Based on the results of ANOVA, the F-value and p-value parameters for the desired model were determined to be 783.09 and < 0.0001, respectively, which confirms the success and high ability of the model. The number of R2, adjusted R2, and Predicted R2 for adsorption of Flu ion was determined to be 0.998, 0.997, and 0.995, respectively, which shows that the proposed regression model can describe the process of adsorption and interaction between variables well. Compared to other kinetic models, the pseudo 2nd order kinetic model has a greater ability to describe the Flu adsorption behavior. The R2 parameter value determined that the Freundlich isotherm model has a suitable ability to investigate the isotherm behavior and confirms the effect of heterogeneous surfaces in the process. Generally, the outcomes signified that the MMt and MMt/CoFe2O4/Al-Fe Fum samples can be reused several times in the process of Flu adsorption, while the efficiency is more than 90%.

Predictive modeling of plastic pyrolysis process for the evaluation of activation energy: Explainable artificial intelligence based comprehensive insights.

Pyrolysis, a thermochemical conversion approach of transforming plastic waste to energy has tremendous potential to manage the exponentially increasing plastic waste. However, understanding the process kinetics is fundamental to engineering a sustainable process. Conventional analysis techniques do not provide insights into the influence of characteristics of feedstock on the process kinetics. Present study exemplifies the efficacy of using machine learning for predictive modeling of pyrolysis of waste plastics to understand the complexities of the interrelations of predictor variables and their influence on activation energy. The activation energy for pyrolysis of waste plastics was evaluated using machine learning models namely Random Forest, XGBoost, CatBoost, and AdaBoost regression models. Feature selection based on the multicollinearity of data and hyperparameter tuning of the models utilizing RandomizedSearchCV was conducted. Random forest model outperformed the other models with coefficient of determination (R2) value of 0.941, root mean square error (RMSE) value of 14.69 and mean absolute error (MAE) value of 8.66 for the testing dataset. The explainable artificial intelligence-based feature importance plot and the summary plot of the shapely additive explanations projected fixed carbon content, ash content, conversion value, and carbon content as significant parameters of the model in the order; fixed carbon > carbon > ash content > degree of conversion. Present study highlighted the potential of machine learning as a powerful tool to understand the influence of the characteristics of plastic waste and the degree of conversion on the activation energy of a process that is essential for designing the large-scale operations and future scale-up of the process.

Removal of benzophenone-4 via chlorination and advanced oxidation processes in aqueous solution: kinetics, by-product identification, and mechanistic studies.

Benzophenone-4 (BP-4) is one of the UV filters widely used in personal care products (PCPs). BP-4 has been identified as an emergent contaminant detected in influent and effluent of wastewater treatment plants (WWTPs) at high concentrations showing that conventional treatment is unable to remove it, subsequently, the presence of BP-4 in surface water is inevitable. In this study, we focus on the degradation of this compound by chlorine, and we report the efficiency of its removal from water by applying two advanced oxidation processes UV/TiO2 and UV/H2O2 aiming to achieve a superior mineralization result. The study was performed in purified water (pH = 6.5, temperature = 25 °C) with an initial concentration of BP-4 similar to that detected in WWTPs (10 mg/L). The results showed that 76% of BP-4 was degraded after 80 min of reaction with chlorine leading to the formation of one by-product persistent in the solution. The oxidation by UV/TiO2 and UV/H2O2 led to a total removal of BP-4 and their generated by-products after 50 and 10 min of reactions, respectively. The kinetic study showed that BP-4 degradation by UV/H2O2 and UV/TiO2 followed pseudo-first-order reaction kinetics and the apparent rate constants (kapp) were determined to be 0.48 min-1 and 0.08 min-1, respectively. The degradation of BP-4 by chlorine followed first-order reaction kinetics with kapp = 0.02 min-1. The identification of by-product structures was performed using liquid chromatography with electrospray ionization and tandem mass spectrometry (MS/MS. The fragmentation of BP-4 and by-product ions at different collision energies allowed to propose the pathways of degradation and to predict the toxicity using a silico toxicity program which confirmed a higher toxicity of all generated by-products.

Kinetic modeling and optimization of ethanol fermentation by the marine yeast Wickerhamomyces subpelliculosus ZE75.

The study aims to enhance ethanol production by Wickerhamomyces subpelliculosus ZE75 isolated from marine sediment. In addition, analyzing the kinetic parameters of ethanol production and optimization of the fermentation conditions was performed. The marine yeast isolate ZE75 was selected as the front runner ethanol-producer, with an ethanol yield of 89.77 gL-1. ZE75 was identified relying on the phenotypic and genotypic characteristics of W. subpelliculosus. The genotypic characterization based on the Internal Transcribed Spacer (ITS) sequence was deposited in the GenBank database with the accession number OP715873. The maximum specific ethanol production rate (vmax) was 0.482 gg-1 h-1 at 175 gL-1 glucose concentration, with a high accuracy of R2 0.95. The maximum growth specific rates (µmax) were 0.141 h-1 obtained at 150 gL-1 glucose concentration with R2 0.91. Optimization of the fermentation parameters such as pH and salinity has been achieved. The highest ethanol yield 0.5637 gg-1 was achieved in a 100% natural seawater-based medium. The maximum ethanol production of 104.04 gL-1 was achieved at pH 4.5 with a specific ethanol rate of 0.1669 gg-1 h-1. The findings of the present study recommend the possibility of ethanol production from a seawater-based medium on a large scale using W. subpelliculosus ZE75.

The Luminescence of Laser-Produced Carbon Nanodots: The Effect of Aggregation in PEI Solution.

Carbon nanodots (CNDs) produced in pure water by the ablation of graphite with a nanosecond laser pulse exhibit weak photoluminescence. A small addition of polyethyleneimine (PEI) to the aqueous suspension of CNDs causes a significant increase in emissions. This paper presents experimental and theoretical studies of the emission properties of CND/PEI systems. The obtained CNDs responded to even trace amounts of PEI in solution (~0.014% v/v), resulting in a significant increase in the initial weak blue emission of CNDs and PEI taken separately. Morphology and size measurements showed that particle aggregation occurred in the presence of the polymer. A decrease in the calculated Stokes shift values was observed with increasing PEI content in the solution. This indicates a reduction in the number of non-radiative transitions, which explains the increase in the emission intensity of the CND/PEI systems. These results therefore confirmed that the increase in the emission of CND/PEI systems is caused by particle aggregation. Kinetic studies proved that the process is controlled mainly by diffusion, the initial stage of which has a dominant influence on determining the optical properties of the system.

Automated Monitoring System for Suspended Photocatalytic Batch Reactions Based on Online Circulatory Spectrophotometry.

Employing an automated monitoring system (AMS) for data acquisition offers benefits, such as reducing the workload, in the kinetic study of suspended photocatalytic batch reactions. However, the current methods in this field tend to narrowly focus on the substrate and often overlook the optical characteristics of both the mixture and solid particles. To address this limitation, in this study, we propose a novel AMS based on online circulatory spectrophotometry (OCS) and incorporate debubbling, aeration, and segmented flow (DAS), named DAS-OCS-AMS. Initially, a debubbler is introduced to mitigate the issue of signal noise caused by bubbles (SNB). Subsequently, an aerated and segmented device is developed to address the issue of particle deposition on the inner wall of the pipeline (PDP) and on the windows of the flow cell (PDW). The proposed DAS-OCS-AMS is applied to monitor the kinetics of the photocatalytic degradation of Acid Orange Ⅱ by TiO2 (P25), and its results are compared with those obtained using the traditional OCS-AMS. The comparative analysis indicates that the proposed DAS-OCS-AMS effectively mitigates the influence of SNB, PDP, and PDW, yielding precise results both for the mixture and solid particles. The DAS-OCS-AMS provides a highly flexible universal framework for online circulatory automated monitoring and a robust hardware foundation for subsequent data processing research.

Experimental kinetics and thermodynamics investigation: Chemically activated carbon-enriched monolithic reduced graphene oxide for efficient CO2 capture.

In this research, we have developed solid MGOs by self-assembled reduction process of GO at 90 °C with different weight ratios of oxalic acid (1:1, 1:0.500, and 1:0.250). The as-synthesized monoliths were carbonized (at 600 °C) and chemically activated with varying proportions of NaOH (1:1, 1:2, and 1:3). This materials offer the CO2 adsorption effect under dynamic conditions, fast mass transfer, easy handling, and outstanding stability throughout the adsorption-desorption cycle. FE-SEM, and HR-TEM analyses confirmed the porous nature and shape of the adsorbents, while XPS examination revealed the presence of distinct functional groups on the surface of the monolith. By increasing the mass ratios (MGO:NaOH) from 1:1 to 1:2, the surface areas increased by approximately 2.6 times, ranging from 520.8 to 753.9 m2 g⁻1 (surface area of the untreated MGO was 289.2 m2 g⁻1). Consequently, this resulted in a notable enhancement of 2.10 mmol g⁻1 in dynamic CO2 capture capacity. The assessment encompassed the evaluation of production yield, selectivity, regenerability, kinetics, equilibrium isotherm, and isosteric temperatures of adsorption (Qst). The decrease in CO2 capture effectiveness with rising adsorption temperature indicated an exothermic and physisorption process. The regenerability of 99.1 % at 100 °C and excellent cyclic stability with efficient CO2 adsorption make this monolithic adsorbent appropriate for post-combustion CO2 capture. The significant Qst lend support to the heterogeneity of the adsorbent's surface, and the pseudo-second-order kinetic model along with the Freundlich isotherm model emerged as the most fitting. Therefore, the current investigation shows that the carbon-enriched adsorbents enhance the CO2 adsorption capacity. It may be used as a low-cost pretreatment method on an industrial scale before carbon capture.

Enhanced Reactivities of Iron(IV)-Oxo Porphyrin Species in Oxidation Reactions Promoted by Intramolecular Hydrogen-Bonding.

High-valent iron-oxo species are one of the common intermediates in both biological and biomimetic catalytic oxidation reactions. Recently, hydrogen-bonding (H-bonding) has been proved to be critical in determining the selectivity and reactivity. However, few examples have been established for mechanistic insights into the H-bonding effect. Moreover, intramolecular H-bonding effect on both C-H activation and oxygen atom transfer (OAT) reactions in synthetic porphyrin model system has not been investigated yet. In this study, a series of heme-containing iron(IV)-oxo porphyrin species with or without intramolecular H-bonding are synthesized and characterized. Kinetic studies revealed that intramolecular H-bonding can significantly enhance the reactivity of iron(IV)-oxo species in OAT, C-H activation, and electron-transfer reactions. This unprecedented unified H-bonding effect is elucidated by theoretical calculations, which showed that intramolecular H-bonding interactions lower the energy of the anti-bonding orbital of iron(IV)-oxo porphyrin species, resulting in the enhanced reactivities in oxidation reactions irrespective of the reaction type. To the best of the knowledge, this is the first extensive investigation on the intramolecular H-bonding effect in heme system. The results show that H-bonding interactions have a unified effect with iron(IV)-oxo porphyrin species in all three investigated reactions.

Cycloartane-type triterpenoids from the leaves of Sandoricum koetjape and their efficacy on α-glucosidase inhibition activity.

The preliminary α-glucosidase inhibitory activity of the methanol extract of the leaves of Sandoricum koetjape Merr. exhibited promising results. The leaves was extracted with methanol to obtain the methanol extract that was continuedly partitioned with hexane and ethyl acetate. Those fractions were further purified by various chromatographic techniques. The isolation of the potent fractions furnished two new cycloartane-type triterpenoids (1 and 2) along with ten known compounds (3-12). Their chemical structures were unambiguously established by interpretation of NMR (1 D & 2 D) and high-resolution electrospray ionization mass spectrometry (HRESIMS) data. Furthermore, the configurations of two new compounds were determined by using NOESY spectrum as well as comparing their NMR data to the reference. These compounds were evaluated against α-glucosidase. All tested compounds revealed potent activity with IC50 value in the range of 2.17-49.2 µM compared to that of acarbose (IC50 100.6 µM). Compound 10 showed the lowest IC50 value. This compound was reported as a mixed-type inhibitor. Compound 3 possessed the second strong activity with an IC50 value of 14.0 µM and was further investigated on kinetic analysis which revealed as a mixed-type inhibitor with Ki and Ki' values of 59.1 and 155.2 µM, respectively.

An experimental and modeling approach to describe the deactivation of cellulases at the air-liquid interface.

Understanding the reaction mechanisms involved in the enzymatic hydrolysis of cellulose is important because it is kinetically the most limiting step of the bioethanol production process. The present work focuses on the enzymatic deactivation at the air-liquid interface, which is one of the aspects contributing to this global deactivation. This phenomenon has already been experimentally proven, but this is the first time that a model has been proposed to describe it. Experiments were performed by incubating Celluclast cocktail solutions on an orbital stirring system at different enzyme concentrations and different surface-to-volume ratios. A 5-day follow-up was carried out by measuring the global FPase activity of cellulases for each condition tested. The activity loss was proven to depend on both the air-liquid surface area and the enzyme concentration. Both observations suggest that the loss of activity takes place at the air-liquid surface, the total amount of enzymes varying with volume or enzyme concentration. Furthermore, tests performed using five individual enzymes purified from a Trichoderma reesei cocktail showed that the only cellulase that is deactivated at the air-liquid interface is cellobiohydrolase II. From the experimental data collected by varying the initial enzyme concentration and the ratio surface to volume, it was possible to develop, for the first time, a model that describes the loss of activity at the air-liquid interface for this configuration.

Synthesis and biological evaluation of triazolones/oxadiazolones as novel urease inhibitors.

Urease is the main virulence factor of infectious gastritis and gastric ulcers. Urease inhibitors are regarded as the first choice for the treatment of such diseases. Based on the triazolone/oxadiazolone skeleton, a urea-like fragment being able to specifically bind the urease activity pocket and prevent urea from hydrolysis, we designed and synthesized 45 triazolones/oxadiazolones as urease inhibitors. Eight compounds were proved to show excellent inhibitory activity against Helicobacter pylori urease, being more potency than the clinically used urease inhibitor acetohydroxamic acid. The most active inhibitor with IC50 value of 1.2 µM was over 20-fold higher potent than the positive control. Enzymatic kinetic assays showed that these novel inhibitors reversibly inhibited urease with a mixed competitive mechanism. Molecular dockings provided evidence for the observations in enzyme assays. Furthermore, these novel inhibitors were proved as drug-like compounds with very low cytotoxicity to mammalian cells and favorable water solubility. These results suggested that triazolone and oxadiazolone were promising scaffolds for the design and discovery of novel urease inhibitors, and were expected as good candidates for further drug development.

Progress and challenges in valorisation of biomass waste from ornamental trees pruning through pyrolysis processes. Prospects in the bioenergy sector.

Nowadays, the scarcity of energy resources is promoting the search for alternative energy sources, boosting interest in the use of forest lignocellulosic residue in the energy sector. In this study, the focus is on the energy recovery from two lignocellulosic residues originated during the pruning of ornamental trees (Horse Chestnut, CI, and False Acacia, FA). Both conventional and flash pyrolysis techniques were applied. The experimental pyrolysis variables were obtained from the study of the thermal behaviour of the pruning residues in thermogravimetric analysis. It was carried out under 5 heating rates and kinetic parameters were estimated using Flynn-Wall-Ozawa method. Results denoted higher maximum mass loss rate values for the same release temperature regions under FA experiments. Also, FA samples had lower final residues for the processes. However, activation energy values were so close for both species. FA was also linked to the faster reactions according frequency factor outcomes. Conventional pyrolysis of pruning residues was carried out in a horizontal oven of original design at a heating rate of 25 °C/min, at 750 °C and 60 min of permanence at that temperature; flash pyrolysis was tested in that oven at 750 and 850 °C. In these pyrolysis processes, three fractions were obtained: bio-char, bio-oil and gas. The physicochemical attributes of the bio-chars suggested their potential utility as biofuels (28.4-29.8 MJ/kg), adsorbent precursors or soil additives. Conventional pyrolysis bio-oils had a dominant monoaromatic hydrocarbons nature, with phenols being the most abundant (≥60%), while flash bio-oils contain mainly polycyclic aromatic hydrocarbons. Conventional pyrolysis gases contained up to 60 vol% of CO2; flash pyrolysis gases had high combustible gas content (CO, CH4, H2) and a low CO2 content (<25 vol%). As a result, their calorific value (18.06 MJ/kg) exhibited a threefold increase compared to the gas produced through conventional pyrolysis (6.04 MJ/kg).