Loss Of Activity Research Articles

A review on drug interaction

Drug interaction occur when the response of one drug is altered by the simultaneous or closely time administration of another drug. Polypharmacy involving the simultaneous use of multiple drugs, raise concern due to unpredictable and potential severe internation. While some drug interactions are intentionally utilized in therapeutics strategies, their severity can vary making prediction challenging. Prescribing multiple medications increases the risk of drug interactions, which can occur with other drugs, foods, beverages, and herbs, both inside and outside the body. Understanding in vitro interactions is crucial to prevent drug activity loss before administration. While not all theoretical drug interactions may occur in practice, they remain a significant cause of adverse events associated with drug administration. Drug-drug interactions (DDIs) represent a significant source of medication errors in developed nations, especially among the elderly who often take multiple medications simultaneously, leading to a prevalence of 20-40%. The complexity of managing therapy increases with poly-therapy, elevating the risk of clinically significant DDIs that can either trigger adverse drug reactions or diminish clinical efficacy. DDIs are typically categorized into two groups: pharmacokinetic and pharmacodynamic. In vivo interactions at pharmacokinetic level affect absorption, distribution, biotransformation or excretion of drugs. Induction or inhibition of cytochrome P450 (CYP450) enzymes forms a major basis of drug interactions. Induction of metabolism of a substrate drug leads to treatment failure.

Development of a Cobalt Catalyst from ZIF‐67 and Application in the Hydrogenation of N‐Heteroarenes

AbstractHydrogenation of N‐heteroarenes to saturated N‐heterocycles is an important reaction in organic synthesis. Hydrogen is a green reducing reagent and has been widely applied in industrial production. The development of an appropriate catalyst to realize hydrogenation at low pressure and temperature is desired. In this study, we developed a cobalt‐based catalyst derived from ZIF‐67 that exhibits high activity for N‐heteroarene hydrogenation under 5–20 bar hydrogen, which is a relatively low pressure as compared to reported catalytic systems. This nano‐cobalt catalyst shows broad substrate scope and can be reused without obvious activity loss.

Ruthenium-Catalyzed Selective Mono N-Ethylation of Arylamines and Tandem Reduction/N-Ethylation of Nitroarenes Using Triethylamine and Formic Acid.

The mono N-alkylation of arylamines using alkylamines as alkyl group donors has been scarcely investigated. In this work, we report the mono N-alkylation of several arylamines (52-95%) catalyzed by the complex ruthenium-triphos in the presence of Al(OTf)3. Moreover, the highly reductant ability of the catalyst system allows the tandem reduction/N-alkylation of nitrobenzenes in good yields (up to 80%). In addition, the catalyst can be recycled after three reaction cycles without loss of catalyst activity.

Efficient Glucose Isomerization to Fructose using Photoregenerable MgSnO3 Catalyst with Cooperative Acid-Base Sites.

The isomerization of glucose to fructose plays a crucial role in the food industry and the production biomass-derived chemicals in biorefineries. However, the catalyst used in this reaction suffers from low selectivity and catalyst deactivation due to carbon or by-product deposition. In this study, MgSnO3 catalyst, synthesized via a facile two-step process involving hydrothermal treatment and calcination, was used for glucose isomerization to fructose. The catalyst demonstrated outstanding catalytic performance, achieving a fructose equilibrium yield of 29.8% with a selectivity exceeding 90% under mild conditions owing to its acid-base interaction. Notably, spent catalysts can be regenerated by photoirradiation to remove surface carbon, thereby avoiding the changes in properties and subsequent loss of activity associated with conventional calcination regeneration method. This novel approach eliminates the energy consumption and potential structural aggregation associated with traditional calcination regeneration methods. The acid-base active sites of the catalyst, along with their corresponding catalytic reaction mechanism and photoregeneration mechanism were investigated. This study presents a demonstration of the comprehensive utilization of catalytic material properties, i.e., acid-base and photocatalytic functionalities, for the development of a green and sustainable biomass thermochemical conversion system.

Mechanistic study of the differences in lactic acid bacteria resistance to freeze- or spray-drying and storage

Lactobacillus delbrueckii subsp. bulgaricus and Lactiplantibacillus plantarum are two lactic acid bacteria (LAB) widely used in the food industry. The objective of this work was to assess the resistance of these bacteria to freeze- and spray-drying and study the mechanisms involved in their loss of activity. The culturability and acidifying activity were measured to determine the specific acidifying activity, while membrane integrity was studied by flow cytometry. The glass transitions temperature and the water activity of the dried bacterial suspensions were also determined. Fourier transform infrared (FTIR) micro-spectroscopy was used to study the biochemical composition of cells in an aqueous environment. All experiments were performed after freezing, drying and storage at 4, 23 and 37 °C. The results showed that Lb. bulgaricus CFL1 was sensitive to osmotic, mechanical, and thermal stresses, while Lpb. plantarum WCFS1 tolerated better the first two types of stress but was more sensitive to thermal stress. Moreover, FTIR results suggested that the sensitivity of Lb. bulgaricus CFL1 to freeze-drying could be attributed to membrane and cell wall degradation, whereas changes in nucleic acids and proteins would be responsible of heat inactivation of both strains associated with spray-drying. According to the activation energy values (47–85 kJ/mol), the functionality loss during storage is a chemically limited reaction. Still, the physical properties of the glassy matrix played a fundamental role in the rates of loss of activity and showed that a glass transition temperature 40 °C above the storage temperature is needed to reach good preservation during storage.Key points• Specific FTIR bands are proposed as markers of osmotic, mechanic and thermal stress• Lb. bulgaricus CFL1 was sensitive to all three stresses, Lpb. plantarum WCFS1 to thermal stress only• Activation energy revealed chemically limited reactions ruled the activity loss in storageGraphical abstract

Quasi-Solid-State Electrolyte Induced by Metallic MoS2 for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are a promising high-energy-density technology for next-generation energy storage but suffer from an inadequate lifespan. The poor cycle life of Li-S batteries stems from their commonly adopted catholyte-mediated operating mechanism, where the shuttling of dissolved polysulfides results in active material loss on the sulfur cathode and surface corrosion on the lithium anode. Here, we report in situ formation of a quasi-solid-state electrolyte (QSSE) on the metallic 1T phase molybdenum disulfide (MoS2) host that extends the lifetime of Li-S batteries. We find that the metallic 1T phase MoS2 host is able to initiate the ring-opening polymerization of 1,3-dioxolane (DOL), forming an integrated QSSE inside batteries. Nuclear magnetic resonance analysis reveals that the QSSE consists of ∼13% liquid DOL in a solid polymer matrix. The QSSE efficiently mediates sulfur redox reactions through dissolution-conversion chemistry while simultaneously suppressing polysulfide shuttling. Therefore, while ensuring high sulfur utilization, it avoids degradation of both electrodes, as well as the concomitant electrolyte consumption, leading to enhanced cycling stability. Under a practical lean electrolyte condition (electrolyte-to-sulfur ratio = 2 μL mg-1), Li-S pouch cell batteries with the QSSE demonstrate a capacity retention of 80.7% after 200 cycles, much superior to conventional liquid electrolyte cells that fail within 70 cycles. The QSSE also enables Li-S pouch cell batteries to operate across a wider temperature range (5 to 45 °C), together with improved safety under mechanical damage.

Network Reconfiguration for Loss Reduction Using Tabu Search and a Voltage Drop

This paper introduces a new algorithm designed to address the challenge of distribution network reconfiguration, employing the tabu search metaheuristic in conjunction with the voltage drop concept. Distinguishing itself from existing methods, our proposed approach not only utilizes voltage drop for obtaining the initial solution but also introduces a novel technique for generating a candidate solution neighborhood. This method leverages both randomness and voltage drop, ensuring a smooth and steady descent during algorithm execution. The primary goal of our algorithm is to minimize active power losses within distribution networks. To validate its effectiveness, the proposed method underwent testing on three commonly referenced distribution systems: the 33-Bus, 69-Bus, and 94-Bus systems, widely acknowledged in the literature. A pivotal aspect of our work involves the synergy of the tabu search algorithm with a combination of both random and deterministic methods for generating neighbors. This strategic amalgamation plays a crucial role, enabling rapid execution while consistently yielding high-quality solutions. Additionally, the adoption of the electric distance method for generating the initial solution adds significant value, offering a commendable solution with minimal computational effort. Comparative assessments against other algorithms documented in the literature underscore the superior efficiency of our proposed algorithm.

Strong Metal-Support Interaction Modulation between Pt Nanoclusters and Mn3O4 Nanosheets through Oxygen Vacancy Control to Achieve High Activities for Acidic Hydrogen Evolution.

The optimization of metal-support interactions is used to fabricate noble metal-based nanoclusters with high activity for hydrogen evolution reaction (HER) in acid media. Specifically, the oxygen-defective Mn3O4 nanosheets supported Pt nanoclusters of ≈1.71nm in diameter (Pt/V·-Mn3O4 NSs) are synthesized through the controlled solvothermal reaction. The Pt/V·-Mn3O4 NSs show a superior activity and excellent stability for the HER in the acidic media. They only require an overpotential of 19mV to drive -10mAcm-2 and show negligible activity loss at -10 and -250mAcm-2 for >200 and >60h, respectively. Their Pt mass activity is 12.4 times higher than that of the Pt/C and even higher than those of many single-atom based Pt catalysts. DFT calculations show that their high HER activity arises mainly from the strong metal-support interaction between Pt and Mn3O4. It can facilitate the charge transfer from Mn3O4 to Pt, optimizing the H adsorption on the catalyst surface and promoting the evolution of H2 through the Volmer-Tafel mechanism. The oxygen vacancies in the V·-Mn3O4 NSs are found to be inconducive to the high activity of the Pt/V·-Mn3O4 NSs, highlighting the great importance to reduce the vacancy levels in V·-Mn3O4 NSs.

Impact of Co and Cu co‐doping on the Structural, Electrical, Magnetic and Solar Light Driven Photo‐Catalytic Properties of NiFe2O4 Nano‐crystals for Crystal Violet Dye Removal

AbstractHerein, we have synthesised cobalt (Co) and copper (Cu) co‐doped Ni‐ferrite Ni1‐xCoxFe2‐yCuyO4 nanocrystals (NCs) via the facile micro‐emulsion method. The materials were analysed for various physio‐chemical characterizations to investigate the co‐doping (Co and Cu) effects on magnetic, structural, electrical, photo‐catalytic properties. The structural analysis via Fourier Transform Infrared spectroscopy (FTIR) and X‐rays diffraction (XRD) showed the successful fabrication of Co and Cu co‐doped materials with cubic spinel geometry having a single phase, the crystallite size was observed in 15 to 24 nm range. The electrical response measured using current‐voltage (I–V) analysis showed good electrical features, the electrical resistivity declined from 6.85×107 Ohm.cm for un‐doped materials to 0.04×107 Ohm.cm for co‐doped materials, which was accredited due to the synergistic effects of Co and Cu metal cations in co‐doped Ni‐based ferrite structures. Magnetic investigation using VSM analysis showed increased saturation magnetization (Ms 31.32 to 50.75 emu/g) and coercivity (218.76 to 406.82 Oe) because of the higher magnetic responses of Co2+ions in the co‐doped spinel ferrite NCs. BET surface‐area analysis showed good porosity for co‐doped materials with an increased surface area of 52 to 104 m2/g on co‐doping. The Tauc's plot described the decline of band‐gap energies value (Egs) (1.99 eV) in co‐doped (x=y=0.56) materials as compared to (2.16 eV) of the un‐doped NiFe2O4 materials, which is due to more electrical responses of Co and Cu co‐dopant cations that possess higher energy levels, which can stabilize the charge carrier‘s species. Furthermore, the photo‐degradation using solar light showed good removal of crystal violet (CV) dye, which was almost 94.14 % by co‐doped material; however, by un‐doped material, it was 38.044 %. The scavenger experiment shows that the (OH⋅) hydroxyl radicals and (e−/h+) species play a prime role in the degradation of CV dye. Recycling and recoverability tests for five cycles’ exhibited outstanding stability of the photocatalyst with only 1.7 % losses in activity. Overall, our results showed that co‐doped Ni1‐xCoxFe2‐yCuyO4 NCs materials exhibited enhancement in the magnetic, electrical, photo‐catalytic properties and a decline in band‐gap energy values as compared to un‐doped NiFe2O4, which might have potential use in magnetic and electrical devices as well as solar‐driven photo‐catalyst materials for the remediation of environmental pollution.

Stable Diamine Functionalized Graphene Supported Pd Nanoparticles Showing Excellent Catalytic Activity For Mizoroki–Heck Coupling Reactions

AbstractWe used a simple technique to create palladium nanoparticles on diamine functionalised graphene (Pd(0)‐AAPTMS@G) with an average particle size of 5.5 nm. Our earlier research described the Pd(0)‐AAPTMS@G material as an effective catalyst with outstanding conversion and yields for the Suzuki coupling reaction. We reported the characterisation data for Pd(0)‐AAPTMS@G catalysts previously. Here, we provide a narrative for the excellent selectivity and high yields (92–100 %) for the Mizoroki–Heck coupling product over the same Pd(0)‐AAPTMS@G catalyst. Six uses of the generated catalyst are possible without any activity loss. We also compared the catalyst characterisation for both fresh and reused catalysts.

In vivo Metabolic Sensing of Hyperpolarized [1‐13C]Pyruvate in Mice Using a Recyclable Perfluorinated Iridium Signal Amplification by Reversible Exchange Catalyst

Real‐time visualization of metabolic processes in vivo provides crucial insights into conditions like cancer and metabolic disorders. Metabolic magnetic resonance imaging (MRI), by amplifying the signal of pyruvate molecules through hyperpolarization, enables non‐invasive monitoring of metabolic fluxes, aiding in understanding disease progression and treatment response. Signal Amplification By Reversible Exchange (SABRE) presents a simpler, cost‐effective alternative to dissolution dynamic nuclear polarization, eliminating the need for expensive equipment and complex procedures. We present the first in vivo demonstration of metabolic sensing in a human pancreatic cancer xenograft model compared to healthy mice. A novel perfluorinated Iridium SABRE catalyst in a fluorinated solvent and methanol blend facilitated this breakthrough with a 2.2‐fold increase in [1‐13C]pyruvate SABRE hyperpolarization. The perfluorinated moiety allowed easy separation of the heavy‐metal‐containing catalyst from the hyperpolarized [1‐13C]pyruvate target. The perfluorinated catalyst exhibited recyclability, maintaining SABRE‐SHEATH activity through subsequent hyperpolarization cycles with minimal activity loss after the initial two cycles. Remarkably, the catalyst retained activity for at least 10 cycles, with a 3.3‐fold decrease in hyperpolarization potency. This proof‐of‐concept study encourages wider adoption of SABRE hyperpolarized [1‐13C]pyruvate MR for studying in vivo metabolism, aiding in diagnosing stages and monitoring treatment responses in cancer and other diseases.

In vivo Metabolic Sensing of Hyperpolarized [1-13 C]Pyruvate in Mice Using a Recyclable Perfluorinated Iridium Signal Amplification by Reversible Exchange Catalyst.

Real-time visualization of metabolic processes in vivo provides crucial insights into conditions like cancer and metabolic disorders. Metabolic magnetic resonance imaging (MRI), by amplifying the signal of pyruvate molecules through hyperpolarization, enables non-invasive monitoring of metabolic fluxes, aiding in understanding disease progression and treatment response. Signal Amplification By Reversible Exchange (SABRE) presents a simpler, cost-effective alternative to dissolution dynamic nuclear polarization, eliminating the need for expensive equipment and complex procedures. We present the first in vivo demonstration of metabolic sensing in a human pancreatic cancer xenograft model compared to healthy mice. A novel perfluorinated Iridium SABRE catalyst in a fluorinated solvent and methanol blend facilitated this breakthrough with a 2.2-fold increase in [1-13C]pyruvate SABRE hyperpolarization. The perfluorinated moiety allowed easy separation of the heavy-metal-containing catalyst from the hyperpolarized [1-13C]pyruvate target. The perfluorinated catalyst exhibited recyclability, maintaining SABRE-SHEATH activity through subsequent hyperpolarization cycles with minimal activity loss after the initial two cycles. Remarkably, the catalyst retained activity for at least 10 cycles, with a 3.3-fold decrease in hyperpolarization potency. This proof-of-concept study encourages wider adoption of SABRE hyperpolarized [1-13C]pyruvate MR for studying in vivo metabolism, aiding in diagnosing stages and monitoring treatment responses in cancer and other diseases.

Dose-dependent effects of Dnmt3a in an inducible murine model of KrasG12D-driven leukemia

DNMT3A mutations are frequently found in clonal hematopoiesis and a variety of hematologic malignancies, including acute myeloid leukemia. An assortment of mouse models have been engineered to explore the tumorigenic potential and malignant lineage bias due to loss of function of DNMT3A in consort with commonly comutated genes in myeloid malignancies, such as Flt3, Nras, Kras, and c-Kit. We employed several tamoxifen-inducible Cre-ERT2 murine model systems to study the effects of constitutively active KrasG12D-driven myeloid leukemia (Kras) development together with heterozygous (3aHet) or homozygous Dnmt3a deletion (3aKO). Due to the rapid generation of diverse nonhematologic tumors appearing after tamoxifen induction, we employed a transplantation model. With pretransplant tamoxifen induction, most Kras mice died quickly of T-cell malignancies regardless of Dnmt3a status. Using posttransplant induction, we observed a dose-dependent effect of DNMT3A depletion that skewed the leukemic phenotype toward a myeloid lineage. Specifically, 64% of 3aKO/Kras mice had exclusively myeloid disease compared with 36% of 3aHet/Kras and only 13% of Kras mice. Here, 3aKO combined with Kras led to increased disease burden, multiorgan infiltration, and faster disease progression. DOT1L inhibition exerted profound antileukemic effects in malignant 3aKO/Kras cells, but not malignant cells with Kras mutation alone, consistent with the known sensitivity of DNMT3A-mutant leukemia to DOT1L inhibition. RNAseq from malignant myeloid cells revealed that biallelic Dnmt3a deletion was associated with loss of cell-cycle regulation, MYC activation, and TNF⍺ signaling. Overall, we developed a robust model system for mechanistic and preclinical investigations of acute myeloid leukemia with DNMT3A and Ras-pathway lesions.

ATP1A3 Disease Spectrum Includes Paroxysmal Weakness and Encephalopathy Not Triggered by Fever.

Heterozygous pathogenic variants in ATP1A3, which encodes the catalytic alpha subunit of neuronal Na+/K+-ATPase, cause primarily neurologic disorders with widely variable features that can include episodic movement deficits. One distinctive presentation of ATP1A3-related disease is recurrent fever-triggered encephalopathy. This can occur with generalized weakness and/or ataxia and is described in the literature as relapsing encephalopathy with cerebellar ataxia. This syndrome displays genotype-phenotype correlation with variants at p.R756 causing temperature sensitivity of ATP1A3. We report clinical and in vitro functional evidence for a similar phenotype not triggered by fever but associated with protein loss-of-function. We describe the phenotype of an individual with de novo occurrence of a novel heterozygous ATP1A3 variant, NM_152296.5:c.388_390delGTG; p.(V130del). We confirmed the pathogenicity of p.V130del by cell survival complementation assay in HEK293 cells and then characterized its functional impact on enzymatic ion transport and extracellular sodium binding by two-electrode voltage clamp electrophysiology in Xenopus oocytes. To determine whether variant enzymes reach the cell surface, we surface-biotinylated oocytes expressing N-tagged ATP1A3. The proband is a 7-year-old boy who has had 2 lifetime episodes of paroxysmal weakness, encephalopathy, and ataxia not triggered by fever. He had speech regression and intermittent hand tremors after the second episode but otherwise spontaneously recovered after episodes and is at present developmentally appropriate. The p.V130del variant was identified on clinical trio exome sequencing, which did not reveal any other variants possibly associated with the phenotype. p.V130del eliminated ATP1A3 function in cell survival complementation assay. In Xenopus oocytes, p.V130del variant Na+/K+-ATPases showed complete loss of ion transport activity and marked abnormalities of extracellular Na+ binding at room temperature. Despite this clear loss-of-function effect, surface biotinylation under the same conditions revealed that p.V130del variant enzymes were still present at the oocyte's cell membrane. This individual's phenotype expands the clinical spectrum of ATP1A3-related recurrent encephalopathy to include presentations without fever-triggered events. The total loss of ion transport function with p.V130del, despite enzyme presence at the cell membrane, indicates that haploinsufficiency can cause relatively mild phenotypes in ATP1A3-related disease.

Improved catalytic performance of Ru catalysts via CO2-assisted one-pot synthesis strategy for aqueous levulinic acid hydrogenation

Fabrication of metal/porous carbon catalysts with high catalytic activity and stability is highly desirable but challenging because the metal nanoparticles in these catalysts cannot have both high exposure and strong interaction with carbon support. Here, for the first time, a facile CO2-assisted one-pot pyrolysis (CAOP) strategy was developed to in situ liberate the inaccessible Ru sites without obviously affecting the size of Ru nanoparticles. The Ru@CN-700-80 prepared with the assistance of CO2 exhibits a remarkable improvement in catalytic activity for levulinic acid hydrogenation compared with that without CO2 during pyrolysis, giving a TOF of 28449 h−1 under mild conditions, which is superior to the reported Ru-based catalysts. Additionally, the Ru@CN-700-80 also demonstrates an excellent stability without activity loss after 10 cycles. We anticipate that this CAOP strategy addresses a crucial issue that currently plagues the design of metal/porous carbon catalyst with high catalytic performance applied in energy and environmental fields.

The KAT module of the SAGA complex maintains the oncogenic gene expression program in MYCN-amplified neuroblastoma.

Pediatric cancers are frequently driven by genomic alterations that result in aberrant transcription factor activity. Here, we used functional genomic screens to identify multiple genes within the transcriptional coactivator Spt-Ada-Gcn5-acetyltransferase (SAGA) complex as selective dependencies for MYCN-amplified neuroblastoma, a disease of dysregulated development driven by an aberrant oncogenic transcriptional program. We characterized the DNA recruitment sites of the SAGA complex in neuroblastoma and the consequences of loss of SAGA complex lysine acetyltransferase (KAT) activity on histone acetylation and gene expression. We demonstrate that loss of SAGA complex KAT activity is associated with reduced MYCN binding on chromatin, suppression of MYC/MYCN gene expression programs, and impaired cell cycle progression. Further, we showed that the SAGA complex is pharmacologically targetable in vitro and in vivo with a KAT2A/KAT2B proteolysis targeting chimeric. Our findings expand our understanding of the histone-modifying complexes that maintain the oncogenic transcriptional state in this disease and suggest therapeutic potential for inhibitors of SAGA KAT activity in MYCN-amplified neuroblastoma.

Soft-templating synthesis of mesoporous MnSiOx composites as catalytic supports for Pd nanoparticles towards solvent-free oxidation of benzyl alcohol under atmospheric pressure O2

Solvent-free and liquid-phase selective oxidation of aromatic alcohols using O2 as an oxidant is a green strategy for the synthesis of aromatic aldehydes and other carbonyl compounds. Wherein, the design and preparation of heterogeneous catalysts with high activity and selectivity is a hot topic in this process. Herein, a series of manganese oxide-silica (MnSiOx) composites were synthesized using cetyltrimethylammonium bromide as a soft template. During the preparation process, the amounts of tetraethyl orthosilicate and ammonia and the calcination temperature significantly affected the textural properties and Mn cation distributions of MnSiOx. The MnSiOx composites were then employed as catalysts for Pd nanoparticles. In the solvent-free and atmospheric conditions, Pd/MnSiOx materials showed high catalytic conversions of benzyl alcohol (BZA), and the catalytic activity thereof is related to the fractions of Pd0 and Mn3+. As the reaction time and temperature are 4 h and 90 °C, the conversion of BZA (feeding dosage: 4 mL) and the selectivity of benzaldehyde are 64.8 % and 94.9 %, respectively. The catalyst can be reused at least five times without any significant loss of activity. Furthermore, the correlation between physiochemical properties and catalytic activity of Pd/MnSiOx was analyzed.

Amorphous MnRuOx Containing Microcrystalline for Enhanced Acidic Oxygen-Evolution Activity and Stability.

Compared to Ir, Ru-based catalysts often exhibited higher activity but suffered significant and rapid activity loss during the challenging oxygen evolution reaction (OER) in a corrosive acidic environment. Herein, we developed a hybrid MnRuOx catalyst in which the RuO2 microcrystalline regions serve as a supporting framework, and the amorphous MnRuOx phase fills the microcrystalline interstices. In particular, the MnRuOx-300 catalyst from an annealing temperature of 300oC contains an optimal amorphous/crystalline heterostructure, providing substantial defects and active sites, facilitating efficient adsorption and conversion of OH-. In addition, the heterostructure leads to a relative increase of the d-band center close to the Fermin level, thus accelerating electron transfer with reduced charge transfer resistance at the active interface between crystalline and amorphous phases during the OER. The catalyst was further thoroughly evaluated under various operating conditions and demonstrated exceptional activity and stability for the OER, representing a promising solution to replace Ir in water electrolyzers.

Using a three-dimensional computational fluid dynamics model and an agglomerate model to investigate the effect of varying agglomerate parameters and output voltages on proton exchange membrane fuel cell performance

Modeling of proton exchange membrane (PEM) fuel cells is attracting more attention as fuel cell technology continues to develop. In this study, we considered a hybrid model that combines an agglomerate model based on the agglomeration of catalyst particles and the coverage-dependent kinetic equation of platinum oxide for ORR, and another 3D numerical model of a PEM fuel cell based on computational fluid dynamics (CFD). The obtained results from our developed models were validated with experimental results from literature. In fact, we investigated the effects of changing the agglomerate radius (Ragg), the ionomer volume fraction within the agglomerate (Yi,agg), the effective agglomerate surface area (Ai,agg), the distribution of the gases and the temperature on the cell performances.The results revealed that the cell performances are strongly influenced by changing Ragg and Yi,agg for medium and high current densities: The activation loss increases with increasing Ragg and decreasing Yi,agg. Also, Ai,agg increases with decreasing Ragg and increasing Yi,agg. In addition, the PEM fuel cell's power output is significantly enhanced when Ragg is decreased and Yi,agg is increased, the optimal power being obtained for values of Ragg=100nm and Yi,agg = 0.6. The numerical results also showed that decreasing the output voltage from 0.95V to 0.35V can accelerate the electrochemical reaction process.

Nanomaterials functionalized acidic ionic organosilica as highly active catalyst in the selective synthesis of benzimidazole via dehydrogenative coupling of diamines and alcohols

An acidic tungstate-based zwitterionic organosilica drived simple self-condensation of tungstic acid and zwitterionic organosilane (PMO-IL-WO42−), was remarkably demonstrated to be highly efficient and environmentally friendly catalyst for directly selective synthesis of benzimidazoles from benzyl alcohols under atmpshpheric air pressure and without any additional oxidant. The one-pot synthesis of benzimidazoles from benzyl alcohols and 1,2-phenylenediamine was efficiently achieved via direct dehydrogenative reaction using a low amount of recoverable PMO-IL-WO42− nanocatalyst in water under ambient conditions with a conversion efficiency of more than 90%. Enhancements in yield and selectivity of benzimidazole formation were observed when water was utilized as the solvent. Furthermore, the PMO-IL-WO42− nanocatalyst exhibited exceptional stability, demonstrating the ability to be effortlessly separated and reused for at least eight reaction cycles without any noticeable loss in activity or product selectivity. This method supports an eco-friendly atom economy and provides a sustainable approach to accessing benzimidazoles directly from benzyl alcohols under mild conditions, demonstrating its potential for practical applications in organic synthesis.