Effect Of pH Research Articles

Effect of pH and biopolymer ratio on phase behavior, rheology, and structural characteristics of pea protein isolate‐locust bean gum coacervates

AbstractBackgroundInteraction between plant‐based proteins and polysaccharides depends on several factors.   This work reports the influence of pH and biopolymer ratios on the protein (pea protein isolate, PPI)‐polysaccharide (locust bean gum, LBG) coacervates. Electrostatic interaction and hydrogen bond between the biopolymers strongly influenced the formation of the coacervates.ResultsThe optimum coacervate conditions were observed at pH 4.5 and PPI:LBG ratio of 5:1. The coacervates showed a honeycomb porous architecture having an amorphous nature. Complex coacervates showed a significant elevation of denaturation temperature as compared to biopolymers alone.ConclusionThese results indicates that PPI‐LBG coacervates can be used as an effective biomaterial for encapsulating heat‐sensitive bioactive compounds and other multiple uses in food processing.

Structural simulation and performance evaluation of a novel synthesized ZIF in the adsorption of MO from aqueous solutions.

Zeolitic imidazolate frameworks (ZIFs) are desirable materials widely applied as adsorbent for wastewater treatment. This study synthesizes and applies a novel structured ZIF with organic ligand of 2-methyl imidazole and metal salt of copper (II) sulfate as adsorbent. Its morphology and structure were investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, field emission scanning electron microscope, energy dispersive X-ray spectrometry, and mapping analysis. After structural analysis, the adsorbent structure was simulated and determined using Avogadro and Gaussian software. The removal efficiency of prepared ZIF in the removal of methyl orange from aqueous solution was evaluated. The effect of pH, the concentration of the dye in solution, dosage of the adsorbent, and the contact time between adsorbent and solution on the methyl orange removal were examined using central composite design of response surface methodology in five levels. The maximum dye removal of 99% was obtained for 2g adsorbent/L, pH of 3.3, and initial dye concentration of 121mg/L after 127min contact time. In addition, to reduce the economic costs and energy consumption, the synthesis time was also reduced and used to show the applicability of the adsorbent prepared and understand its advantages and disadvantages in removing methyl orange dye from aqueous solutions. This molecular adsorbent is stable, and it can be stored for months. On the other hand, this ZIF can be easily recovered and reused many times. In this research, after five times of recovery, there was no significant change in the effectiveness of the adsorbent.

Analysis of Three Dimethyl Sulfides in Freshwater Lakes Using Headspace Solid-Phase Microextraction-Gas Chromatography with Flame Photometric Detection

Dimethyl sulfides are ubiquitous odorous substances in eutrophic freshwater bodies. In this study, a simple headspace solid-phase microextraction-gas chromatography-flame photometric detection method was developed to detect three representative algal-derived dimethyl sulfides in freshwater lake water samples: dimethyl monosulfide (DMS), dimethyl disulfide (DMDS), and dimethyl trisulfide (DMTS). The effects of extraction fiber, temperature, pH, ionic strength, and sample volume were investigated orthogonally, and the optimized method was applied to analyze surface water samples from Lake Ulansuhai in Inner Mongolia, China. Optimal extraction was obtained with a 50/30 µm DVB/CAR/PDMS extraction fiber, 20% ion concentration, 87 min extraction time, and 50 °C extraction temperature. The correlation coefficients of the standardized working curves for DMS, DMDS, and DMTS were 0.9967, 0.9907, and 0.9994, respectively, indicating good linear relationships. Limits of detection were in the nanogram range, and the recoveries of the spiked standards for DMS, DMDS, and DMTS were 97.22~99.07%, 93.39~99.34%, and 91.17~99.25%, with relative standard deviations of 5.18~5.94%, 3.08~6.25%, and 2.56~5.47%, respectively. This method is stable and reliable, and can be used for the determination of volatile sulfides in freshwater lake water.

Responsiveness of Charged Double Network Hydrogels to Ionic Environment

AbstractCharged double network (DN) hydrogels are widely studied for their desirable mechanical strength and tunable properties. In this work, the influence of polymer concentration on microstructure and properties of agarose/polyacrylic acid DN hydrogels is studied. Agarose, the first network, is a brittle biopolymer, while polyacrylic acid (PAAc) is a weak polyelectrolyte. The microstructure, visualized in liquid environment, displays an agarose scaffold coated and interconnected by PAAc, deviating from the common assumption of an entangled double network. Importantly, the charging of PAAc in the hydrogel is regulated not only by the pH and weak polyelectrolyte effects, but also by the restricted swelling of the double network, and hence, it is an inherent regulation mechanism of charged hydrogels. The interactions between the hydrogel and the ionic environment induce microstructural changes and charging of the double network, impacting surface properties such as topography, stiffness, and adhesion, which are spatially resolved by liquid‐environment atomic force microscopy. The responsiveness of the DN hydrogels significantly depends on both polymer concentrations and ion concentrations. These findings provide insights into the responsive behavior of double network hydrogels and reveal universal mechanisms for charged hydrogels, which can guide the future development of functional soft materials.

Microstructure change and functional characteristic promotion: the structural manipulation of soy protein microparticles through pH

SummaryIn this work, soy protein isolates (SPIs) were subjected to microparticulation, turning soy protein ingredients into microparticles with improved thermal stability which could be used in high‐protein foods. The pH is a critical determinant in microparticulation. Our work is mainly to investigate the effect of pH on the formation and properties of protein microparticles. To clarify the effects of pH conditions on the properties of the resulting particles, microparticulation was performed at different pH conditions (7.0, 6.0 and 5.0). Aggregation behaviours described by the parameters calculated from the protein dispersion viscosity combined with the observation of the morphology change were used to analyse the particle formation process. For the microparticles prepared at pH 5.0, soy proteins were more inclined to aggregate into clusters on a micro‐scale which had a flexible conformation. After spray drying, This powder could be easily dispersed in water, creating a dispersion with a protein concentration of 10 wt%. At this concentration, the thermal gelation capacity of the proteins was observed to decrease. Conversely, the tendency of protein aggregation was largely restricted when soy protein microparticulation was carried out at pH 7.0. As these soy protein particles in nano‐scale were dispersed in water, a decrease rather than an increase was recorded in the viscosity of this dispersion after it was heated, suggesting that these particles had improved thermal stability. This work has demonstrated that implementing appropriate pH conditions during microparticulation can prepare soy protein particles with different sizes and rheological properties, which might meet the demands of various food processing.

Tuning Acid-Base Chemistry at an Electrified Gold/Water Interface.

Acid-base reactions are ubiquitous in solution chemistry, as well as in electrochemistry. However, macroscopic concepts derived in solutions, such as pKa and pH, differ significantly at electrified metal-aqueous interfaces due to specific solvation and applied voltage. Here, we measure the pKa values of an amino acid, glycine, at a gold/water interface under a varying applied voltage by means of spectroscopic titration. With the help of simulations, we propose a general model to understand potential-dependent shifts in pKa values in terms of local hydrophobicity and electric fields. These parameters can be tuned by adjusting the metal surface and applied voltage, respectively, offering promising, but still unexplored, paths to regulate reactivity. Our results change the focus with respect to common interpretations based on, for example, apparent local pH effects and open interesting perspectives for electrochemical reaction steering.

Effect of pH on the ozonolysis degradation of p-nitrophenol in aquatic environment and the synergistic effect of hydroxy radical.

Density functional theory (DFT) was employed to elucidate the mechanisms for ozonolysis reaction of p-nitrophenol (PNP) and its anion form aPNP. Thermodynamic data, coupled with Average Local Ionization Energies (ALIE) analysis, reveal that the ortho-positions of the OH/O- groups are the most favorable reaction sites. Moreover, rate constant calculations demonstrate that the O3 attack on the C2-C3 bond is the predominant process in the reaction between neutral PNP and O3. For the aPNP + O3 reaction, the most favorable pathways involve O3 attacking the C1-C2 and C6-C1 bonds. The rate constant for PNP ozonolysis positively correlates with pH, ranging from 5.47 × 108 to 2.86 × 109M-1s-1 in the natural aquatic environment. In addition, the formation of hydroxyl radicals in the ozonation process of PNP and the mechanisms of its synergistic reaction of PNP with ozone were investigated. Furthermore, the ozonation and hydroxylation processes involving the intermediate OH-derivatives were both thermodynamically and kinetic analyzed, which illustrate that OH radicals could promote the elimination of PNP. Finally, the toxic of PNP and the main products for fish, daphnia, green algae and rat were assessed. The findings reveal that certain intermediates possess greater toxicity than the original reactant. Consequently, the potential health risks these compounds pose to organisms warrant serious consideration.

Adsorption of anionic wood dyes on KOH-activated carbons from Pinus radiata sawdust

AbstractChemically activated carbons synthesized from pine sawdust were applied efficiently for the elimination of wood dyes from aqueous solutions. Different proportions (1:2 and 1:4) of activating agent (KOH) and activation temperatures (600 and 850 °C) were used. Carbon surface morphology was characterized. The effect of pH (2–12), initial adsorbate concentration (5–500 mg L−1), and carbon dosage (0.1–0.5 g L−1) on dye adsorption were studied in batch mode. Langmuir model described well the adsorption equilibrium. The maximum found adsorption capacities were 1221.58, 1673.03, and 240.38 mg g−1 for blue and red at 500 mg L−1 and black at 100 mg L−1, respectively, using activated carbon at 850 °C and 1:4 (ACPS-4–850); at 25 °C, adsorbent dose 0.4 g L−1 for blue and black and 0.3 g L−1 for red dye and without change the pH for blue and red and at pH = 2 for black dye. The pseudo-second-order model explained the kinetics of adsorption except for the black dye at 100 mg L−1 using ACPS-4–850 for which it was the pseudo-first-order model. Desorption studies performed with ACPS-4–850 revealed that the adsorption was irreversible by chemical regeneration, whereas for the black dye, regeneration was efficient using H2O2 as desorbing agent.

The Biosorption Capacity of the Marine Microalga Phaeodactylum tricornutum for the Removal of Toluidine Blue from Seawater

A wide variety of dyes, such as toluidine blue (TB), are used daily for a multitude of purposes. After use, many of these compounds end up in aqueous effluents, reaching natural environments, including marine environments. The removal of these pollutants from marine environments must be considered a priority problem. The search for natural techniques, such as biosorption, is a preferred option to eliminate pollution from natural environments. However, biosorption studies in seawater are scarce. For this reason, the living biomass of the marine microalga Phaeodactylum tricornutum was studied to determine its ability to remove TB from seawater. The kinetics of the biosorption process, the isotherms, and the effect of light and pH were determined. This biomass showed a maximum TB removal capacity of 45 ± 2 mg g−1 in the presence of light. Light had a positive effect on the TB removal capacity of this living biomass. The best fitting kinetics was the pseudo-second order kinetics. The efficiency of the removal process increased with increasing pH. This removal was more effective at alkaline pH values. The results demonstrated the efficacy of P. tricornutum living biomass for the efficient removal of toluidine blue dye from seawater both in the presence and absence of light.

Synthesis and Characterization of Activated Carbon from Mahogany Fruit Shell (Khaya senegalensis) Impregnated with TiO2 Used in the Adsorption of Cadmium and Arsenic

In this Study, low-cost activated carbon impregnated with TiO2 (Ac/ TiO2) was prepared from mahogany fruit shell (Khaya senegalensis) by chemical activation using phosphoric acid, H3PO4. The resulting product was evaluated for the removal of Arsenic and Cadmium ions from aqueous solutions. The prepared activated carbon was characterized using SEM, FTIR and XRD. Operational parameters such as initial concentration, adsorbent dose, contact time, effects of pH and temperature were studied in a batch system. It was found that the percentage removal for arsenic and cadmium were around 98 and 97% respectively. Equilibrium of the adsorption processes were obtained by testing the adsorption data using two different isotherm models: Langmuir and Freundlich. The adsorption of arsenic fitted well with Freundlich with R2 value of 0.9106. The kinetic of adsorption process was tested through pseudo first order and pseudo second order models. The Pseudo Second Order Kinetic Model provides the best correlation for the experimental data of both the two metals studied. Thermodynamics parameters, such as ΔGo, ΔHo and ΔS0 were also calculated. This result shows that the process of adsorption for arsenic was spontaneous and exothermic, while that of cadmium was spontaneous and endothermic.

Abstract CT064: Impact of food and high gastric pH on the bioavailability of the WEE1 inhibitor Debio 0123 assessed in a phase 1 dose escalation study

Abstract Debio 0123 (D0123), an oral, brain-penetrant, highly selective WEE1 inhibitor, is currently in clinical development, both in combination and as monotherapy, for the treatment of patients with solid tumors. Food and gastric acid-reducing agents e.g. proton pump inhibitors (PPIs) may modify the solubility, bioavailability, safety and efficacy of oral cancer drugs. Polymedication in cancer patients is common and food restrictions can impact patient compliance and wellbeing. In order to adequately inform drug dosing in clinical trials, effects of food and high gastric pH on D0123 bioavailability were studied over three cycles in patients treated in the dose escalation of a Phase 1 study of D0123 in combination with Carboplatin (CTID NCT03968653).D0123 was given on Days 1-3 and 8-10 of each 21-day cycle in combination with carboplatin on Day 1. Current standard administration of D0123 is in fasted conditions and PPIs are prohibited. Dose-limiting toxicities were evaluated in cycle 1. The effect of food and high-gastric pH were assessed in cycles 2 and 3, respectively. In cycle 2 on Day 10, patients were receiving a high-fat meal and in cycle 3, the PPI lanzoprazole 30 mg BID was administered from Day 7 to 11. PK parameters (area under the curve (AUC), maximum concentration (Cmax)) were determined post-Day 10 dose and compared between cycle 1 (fasted) and cycle 2 (fed) or 3 (high gastric pH). Preliminary data from 3 cohorts, 3 dose levels (n=10) resulted in about 5 pairwise comparisons for food and for high gastric pH effects. Absence of D0123 accumulation between cycles was confirmed, allowing for inter-cycle comparison. Oral bioavailability of D0123 appears pH-dependent, suggesting that co-medication with PPIs should be avoided. In contrast, food intake has a limited impact on drug absorption, at all doses tested. Furthermore, D0123 administration with food may increase treatment convenience and tolerability, leading to its implementation in other D0123 trials. TABLE 1. NAND Mean change [ min ; max ] Effect of food (cycle 2 versus cycle 1) Effect of high gastric pH (cycle 3 versus cycle 1) AUC24 -3% [ -17% ; +8% ] -31% [ -39%; -23% ] Cmax -10% [ -26% ; 0% ] -33% [ -41% ; -20% ] Citation Format: Anne Bellon, Omar Saavedra, Ingrid M. Desar, Mathilde Jalving, Jourik A. Gietema, Carla van Herpen, Stefan van Ravensteijn, Esteban Rodrigo Imedio, Sylvia van Haren, Melanie Wirth, Sandrine Micallef, Vito Dozio, Rikke Frederiksen Franzen, Marie-Claude Roubaudi-Fraschini, Valerie Nicolas-Metral, Hans Gelderblom. Impact of food and high gastric pH on the bioavailability of the WEE1 inhibitor Debio 0123 assessed in a phase 1 dose escalation study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT064.

Isolation and Characterization of Yarrowia lipolytica YQ22 from Diesel Samples for Phenol Biodegradation

Phenolic compounds have gained international interest due to their carcinogenic, toxic, and bioaccumulative properties, causing adverse effects in both animals and humans. As a result, there is a growing interest in finding alternative and eco-friendly treatment routes for phenol by exploring new microbial cultures with potential adaptation and biodegradation capabilities. In this study, the phenol removal efficiency of Yarrowia lipolytica YQ22 under laboratory conditions was determined. The YQ22 strain was obtained from diesel samples from a fuel station in Trujillo, Peru, isolated through serial dilutions on Sabouraud agar, and identified through its morphological characteristics using microscopy and molecular analysis by polymerase chain reaction of the ribosomal DNA internal transcribed spacer (ITS) and 5.8S regions. In the treatment, the effect of pH (5, 6 and 7) and temperature (25°C, 30°C and 35°C) on phenol removal with 2% (v/v) inoculum of Yarrowia lipolytica from 48-hour growth was evaluated. Phenol concentration was measured by high-performance liquid chromatography. A maximum phenol removal percentage of 61.18 was obtained for YQ22 at 30°C, pH 5 and 120 rpm during 48 hours. These findings demonstrate the ability of Yarrowia lipolytica to remove phenol and suggest its potential use in the field of bioremediation of phenolic compounds and their derivatives.

Adsorption properties and mechanism of Cu(II) on virgin and aged microplastics in the aquatic environment.

Microplastics (MPs) migrate by adsorbing heavy metals in aquatic environments and act as their carriers. However, the aging mechanisms of MPs in the environment and the interactions between MPs and heavy metals in aquatic environments require further study. In this study, two kinds of materials, polyamide (PA) and polylactic acid (PLA) were used as target MPs, and the effects of UV irradiation on the physical and chemical properties of the MPs and the adsorption behavior of Cu(II) were investigated. The results showed that after UV irradiation, pits, folds and pores appeared on the surface of aged MPs, the specific surface area (SSA) increased, the content of oxygen-containing functional groups increased, and the crystallinity decreased. These changes enhanced the adsorption capacity of aged MPs for Cu(II) pollutants. The adsorption behavior of the PA and PLA MPs for Cu(II) conformed to the pseudo-second-order model and Langmuir isotherm model, indicating that the monolayer chemical adsorption was dominant. The maximum amounts of aged PA and PLA reached 1.415 and 1.398 mg/g, respectively, which were 1.59 and 1.76 times of virgin MPs, respectively. The effects of pH and salinity on the adsorption of Cu(II) by the MPs were significant. Moreover, factors such as pH, salinity and dosage had significant effects on the adsorption of Cu(II) by MPs. Oxidative complexation between the oxygen-containing groups of the MPs and Cu(II) is an important adsorption mechanism. These findings reveal that the UV irradiation aging of MPs can enhance the adsorption of Cu(II) and increase their role as pollutant carriers, which is crucial for assessing the ecological risk of MPs and heavy metals coexisting in aquatic environments.

Electrochemical cobalt oxidation in chloride media

The green transition, despite recent advances in cobalt-free battery technologies, is still highly dependent on the availability of critical cobalt-based materials. Consequently, there has been increasing interest towards the development of new methods that maximize critical metals recovery from industrial hydrometallurgical solutions. In the current study, direct anodic oxidation of cobalt species from cobalt chloride solutions was studied as one alternative future strategy for cobalt recovery. Electrochemical methods were used (cyclic voltammetry, potentiostatic anodic deposition) and the effect of pH, temperature, and the concentration of cobalt and chloride ions on cobalt precipitation were investigated. The increase of pH and temperature was shown to stabilize the electrochemical oxidation of cobalt, while a decrease in cobalt concentration had a negative effect on precipitation. Scanning Electron Microscope, Atomic Force Microscopy and X-ray Photoelectron Spectroscopy were exploited to evaluate the morphology, structure, and composition of obtained anodic product. Calculated for potentiostatic anodic deposition (at highest studied potential of 1300 mV vs. Ag/AgCl) nucleation mechanism shows that the rate of nucleation for oxygen-cobalt species is faster than the subsequent growth rate of nuclei (instantaneous mechanism). XPS results confirmed that mixed Co3O4/Co(OH)2/CoOOH precipitate could be obtained by optimized anodic potentiostatic deposition in the range from 900 to 1150 mV and pH from 3 to 6 at 60 °C.

Effect of Environmental pH on the Mechanics of Chitin and Chitosan: A Single-Molecule Study.

Chitin and chitosan are important structural macromolecules for most fungi and marine crustaceans. The functions and application areas of the two molecules are also adjacent beyond their similar molecular structure, such as tissue engineering and food safety where solution systems are involved. However, the elasticities of chitin and chitosan in solution lack comparison at the molecular level. In this study, the single-molecule elasticities of chitin and chitosan in different solutions are investigated via atomic force microscope (AFM) based single-molecule spectroscopy (SMFS). The results manifest that the two macromolecules share the similar inherent elasticity in DOSM due to their same chain backbone. However, obvious elastic deviations can be observed in aqueous conditions. Especially, a lower pH value (acid environment) is helpful to increase the elasticity of both chitin and chitosan. On the contrary, the tendency of elastic variation of chitin and chitosan in a larger pH value (alkaline environment) shows obvious diversity, which is mainly determined by the side groups. This basic study may produce enlightenment for the design of intelligent chitin and chitosan food packaging and biomedical materials.

Enhancing the relative abundance of comammox nitrospira in ammonia oxidizer community decreases N2O emission in nitrification exponentially

Comammox Nitrospira and canonical ammonia-oxidizing bacteria (cAOB) generally coexist in activated sludge. In present study, the effect of comammox Nitrospira on N2O production during nitrification of activated sludge was investigated. Comammox Nitrospira and cAOB were separately enriched in two nitrifying reactors, with respective relative abundance of approximately 98% in ammonia oxidizer community. The N2O emission factor (EF) of nitrification in comammox Nitrospira dominated reactor was 0.35%, consistently lower than that (2.2%) in cAOB dominated reactor. When increasing the relative abundance of comammox Nitrospira in ammonia oxidizer community, the N2O EF of nitrification decreased exponentially, which suggested that comammox Nitrospira not only decreased N2O production directly but also might have reduced N2O yield by cAOB. When cAOB dominated the ammonia oxidizer community of sludge, decreasing pH to 6.3, lowering DO to less than 0.5 mg/L, and increasing nitrite concentration enhanced N2O EF dramatically. When comammox Nitrospira became the dominant ammonia oxidizer, however, the N2O EF correlated to nitrite insignificantly and a low DO of 0.2 mg/L and weakly acidic pH (6.3) decreased N2O EF by approximately 70% and 60%, respectively. These results imply that enhancing the relative abundance of comammox Nitrospira in sludge is an effective way to reducing N2O emissions and can also offset the promoting effects of acidic pH, low DO, and high nitrite concentration on N2O production during nitrification.

Abstract CT140: A phase 1 study of the IAP inhibitor xevinapant (Debio 1143) to evaluate food effect and drug-drug interactions with a proton pump inhibitor in healthy volunteers

Abstract INTRODUCTION: Xevinapant is an oral IAP (inhibitor of apoptosis protein) inhibitor designed to restore cancer cell sensitivity to apoptosis, thereby enhancing the efficacy of chemoradiotherapy (CRT) and radiotherapy (RT). Xevinapant 200 mg/d (d1-14, Q3W) + CRT showed clinical benefit vs placebo + CRT in a phase 2 study of patients with locally advanced squamous cell carcinoma of the head and neck (LA SCCHN; NCT02022098). Two phase 3 studies are currently ongoing evaluating xevinapant in combination with CRT (TrilynX; NCT04459715) or RT (XRay Vision; NCT05386550) in patients with LA SCCHN, with dosing under fasting conditions or without regard to food, respectively. METHODS: A 2-stage study (Debio 1143-107) was conducted to assess the effect of food on 2 different formulations of xevinapant and the effect of co-administration with the proton pump inhibitor pantoprazole to evaluate the effect of high gastric pH on bioavailability of xevinapant. Stage 1 was an open-label, randomized, 4-arm, crossover study with 26 healthy volunteers (HV) treated with a single oral dose of xevinapant 200 mg in fasted or fed (high-fat diet) conditions with 2 different formulations. Stage 2 was a randomized, 2-way crossover study with 12 HV treated with a single oral dose of xevinapant 200 mg with or without pantoprazole. Pharmacokinetics (PK) and pharmacodynamics (PD) samples (Ciap1 levels in peripheral blood mononuclear cells [PBMCs]) were collected over 72 h post dose. The utilization of HV to address clinical pharmacology aspects of xevinapant was justified by holistic assessment of the toxicology, safety, and pharmacology profiles. RESULTS: Following a single dose of xevinapant 200 mg, exposures in HV under fasted conditions were consistent with those observed previously in cancer patients. Xevinapant formulations were bioequivalent and were considered safe and well tolerated in both fasted and fed conditions. Food delayed Tmax and decreased xevinapant Cmax by 39% but did not meaningfully alter the extent of absorption of xevinapant, as evidenced by no change in AUC, which is the most relevant exposure metric for efficacy based on xevinapant’s mechanism of action. Stage 2 data indicated that the PK of xevinapant was not affected by treatment with pantoprazole. Ciap1 levels in PBMCs decreased at least 4-fold compared to the baseline for all treatments and were reduced up to 72 h post single dose. No relevant differences in PD were observed across treatments. PK simulations indicated no relevant change in AUC and no impact on target engagement at steady state with food. CONCLUSION: These data indicate that xevinapant can be administered without regard to food or gastric acid reducing agents, which would be advantageous for patient convenience and compliance. Citation Format: Valérie Nicolas-Métral, Elisabeth Rouits, Camille Riff, Dany Spaggiari, Norbert Wiedemann, Pierre Colin, Eleanor Harrison-Moench, Rafael Crabbé, Heidi Nauwelaerts, Andreas Schroeder, Carolina Haefliger, Yulia Vugmeyster. A phase 1 study of the IAP inhibitor xevinapant (Debio 1143) to evaluate food effect and drug-drug interactions with a proton pump inhibitor in healthy volunteers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT140.

Extending the understanding of Shannon's safe stimulation limit for platinum electrodes: biphasic charge-balanced pulse trains in unbuffered saline at pH = 1 to pH = 12.

In neural electrical stimulation, safe stimulation guidelines are essential to deliver efficient treatment by avoiding neural damage and electrode degradation. The widely used Shannon's limit, k, gives conditions on the stimulation parameters to avoid neural damage, however, underlying damage mechanisms are not fully understood. Moreover, the translation from bench testing to in vivo experiments still presents some challenges, including the increased polarisation observed, which may influence charge-injection mechanisms. In this work, we studied the influence on damage mechanisms of two electrolyte parameters that are different in vivo compared to usual bench tests: solution pH and electrolyte gelation. The potential of a platinum macroelectrode was monitored in a three-electrode setup during current-controlled biphasic charge-balanced cathodic-first pulse trains. Maximum anodic and cathodic potential excursions during pulse trains were projected on cyclic voltammograms to infer possible electrochemical reactions. In unbuffered saline of pH ranging from 1 to 12, the maximum anodic potential was systematically located in the oxide formation region, while the cathodic potential was located the molecular oxygen and oxide reduction region when k approached Shannon's damage limit, independent of solution pH. The results support the hypothesis that Shannon's limit corresponds to the beginning of platinum dissolution following repeated cycles of platinum oxidation and reduction, for which the cathodic excursion is a key tipping point. Despite similar potential excursions between solution and gel electrolytes, we found a joint influence of pH and gelation on the cathodic potential alone, while we observed no effect on the anodic potential. We hypothesise that gelation creates a positive feedback loop exacerbating the effects of pH ; however, the extent of that influence needs to be examined further. This work supports the hypothesis of charge injection mechanisms associated with stimulation-induced damage at platinum electrodes. The validity of a major hypothesis explaining stimulation-induced damage was tested and supported on a range of electrolytes representing potential electrode environments, calling for further characterisation of platinum dissolution during electrical stimulation in various testing conditions.

Optimization of vortex-assisted magnetic nanofluid based liquid phase microextraction for fast, green and reliable extraction of ibuprofen from real samples: Multivariate approach

In this research, the vortex-assisted magnetic nanofluid based liquid phase microextraction (VA-MNF-LPME) procedure was optimized using Box–Behnken Design (BBD) for the selective and reliable extraction of ibuprofen from aqueous solutions. Three MNFs were prepared and tested for the selective extraction of ibuprofen. Ultraviolet–visible spectrophotometry (UV–Vis) was used to determine the amount of ibuprofen and measurements were made at a wavelength of 238 nm. The effects of pH, MNF volume, vortex time, volume of back extraction solvent were optimized using BBD. Separation of the MNF phase containing the ibuprofen in aqueous solution was achieved using a neodymium magnet without the need for centrifugation step. Using optimized parameters (pH = 3.4, 690 μL of MNF, 100 s vortex and 230 μL of ethanol), the detection limit and working range of the V-MNF-LPME procedure were 0.6 ng mL−1 and 2–180 ng mL−1, respectively. Relative standard deviations and recovery (for 25 ng mL−1 of ibuprofen solution, N = 5) were 2.8% and 94.1%. Key validation parameters of the method were studied in detail and calculated under optimized conditions. The VA-MNF-LPME procedure was successfully applied to some drugs, baby lettuce and grape leaf samples in ten stages with a standard-addition approach, and quantitative recoveries were obtained (91.4–98.7%).

Advanced remediation in the presence of ferrous iron and carbonate-containing water by oxygen-induced oxidation of organic contaminants

Mechanistic investigations of an environmentally friendly and easy-to-implement oxidation method in the remediation of contaminated anoxic waters, i.e. groundwater, through the sole use of oxygen for the oxygen-induced oxidation of pollutants were the focus of this work. This was achieved by the addition of O2 under anoxic conditions in the presence of ferrous iron which initiated the ferrous oxidation and the simultaneous formation of reactive •OH radicals. The involvement of inorganic ligands such as carbonates in the activation of oxygen as part of the oxidation of Fe2+ in water was investigated, too. The formation of •OH radicals, was confirmed in two different, indirect approaches by a fluorescence-based method involving coumarin as •OH scavenger and by the determination of the oxidation products of different aromatic VOCs. In the latter case, the oxidation products of several typical aromatic groundwater contaminants such as BTEX (benzene, toluene, ethylbenzene, xylenes), indane and ibuprofen, were determined. The influence of other ligands in the absence of bicarbonate and the effect of pH were also addressed.The possibility of activation of O2 in carbonate-rich water i.e. groundwater, may also potentially contribute to oxidation of groundwater contaminants and support other primary remediation techniques.