Iron Carbide Nanoparticles Encapsulated in Mesoporous Fe–N-Doped Graphene-Like Carbon Hybrids as Efficient Bifunctional Oxygen Electrocatalysts

It is highly crucial and challenging to develop bifunctional oxygen electrocatalysts for oxygen reduction reactions (ORRs) and oxygen evolution reactions (OERs) in rechargeable metal-air batteries and unitized regenerative fuel cells (URFCs). Herein, a facile and cost-effective strategy is developed to prepare mesoporous Fe–N-doped graphene-like carbon architectures with uniform Fe₃C nanoparticles encapsulated in graphitic layers (Fe₃C@NG) via a one-step solid-state thermal reaction. The optimized Fe₃[email protected] catalyst shows comparable ORR activity with the state-of-the-art Pt/C catalyst and OER activity with the benchmarking RuO₂ catalyst. The oxygen electrode activity parameter Δ<i>E</i> (the criteria for judging the overall catalytic activity of bifunctional electrocatalysts) value for Fe₃[email protected] is 0.780 V, which surpasses those of Pt/C and RuO₂ catalysts as well as those of most nonprecious metal catalysts. Significantly, excellent long-term catalytic durability holds great promise in fields of rechargeable metal-air batteries and URFCs

Boosted Reactivity of Ammonia Borane Dehydrogenation over Ni/Ni₂P Heterostructure

Ammonia borane (AB) is regarded as a highly promising candidate for chemical hydrogen-storage materials. Developing low-cost yet efficient catalysts for the dehydrogenation of AB is central to achieving hydrogen conversion. Here a heterostructure of Ni/Ni2P nanoparticles deposited on a defective carbon framework for the hydrolysis of AB is developed by elaborately controlling phosphorization conditions. The electronic structure and interfacial interaction of the ternary components are probed by synchrotron-based X-ray absorption fine structure and further simulated via density functional theory. By adjusting the content of Ni and Ni2P in the hetrostructure, the optimized hybrid exhibits catalytic performance of H2 generation from the hydrolysis of AB under ambient conditions with a turnover frequency of 68.3 mol (H2) mol–1 (Cat) min–1 and an activation energy (Ea) of 44.99 kJ mol–1, implying its high potential as an efficient supplement for noble-metal-based catalysts in hydrogen energy applications

Highly Defective Fe-Based Oxyhydroxides from Electrochemical Reconstruction for Efficient Oxygen Evolution Catalysis

Transition metal Fe-dominated materials generally show inefficient electrocatalytic oxygen evolution reaction (OER), while Fe-incorporated multimetallic compounds can exhibit high catalytic activity. In fact, there is always a controversy about the main active sites in Fe-involved OER elelctrocatalysts. Herein, we demonstrate a highly active mono-Fe-based OER electrocatalyst with a very low overpotential of 283 mV at a current density of 10 mA cm–2 and a Tafel slope of 41.4 mV dec–1. Systematic characterization reveals that the OER performance stems from Na dissolution during the electrocatalytic oxidation process, enabling the electrocatalyst reconstruction to form highly defective oxyhydroxides as highly active catalytic sites. Notably, the electrocatalytic activity can be significantly promoted through the introduction of a heterotransition metal. This work provides insights for active sites in OER catalysis, along with a facile route to tune the intrinsic activity

Dopant- and Surfactant-Tuned Electrode–Electrolyte Interface Enabling Efficient Alkynol Semi-Hydrogenation

Electrochemical alkynol semi-hydrogenation has emerged as a sustainable and environmentally benign route for the production of high-value alkenols, featuring water as the hydrogen source instead of H2. It is highly challenging to design the electrode–electrolyte interface with efficient electrocatalysts and their matched electrolytes to break the selectivity-activity stereotype. Here, boron-doped Pd catalysts (PdB) and surfactant-modified interface are proposed to enable the simultaneous increase in alkenol selectivity and alkynol conversion. Typically, compared to pure Pd and commercial Pd/C catalysts, the PdB catalyst achieves both higher turnover frequency (139.8 h–1) and specific selectivity (above 90%) for the semi-hydrogenation of 2-methyl-3-butyn-2-ol (MBY). Quaternary ammonium cationic surfactants that are employed as electrolyte additives are assembled at the electrified interface in response to applied bias potential, establishing an interfacial microenvironment that can facilitate alkynol transfer and hinder water transfer suitably. Eventually the hydrogen evolution reaction is inhibited and alkynol semi-hydrogenation is promoted, without inducing the decrease of alkenol selectivity. This work offers a distinct perspective on creating a suitable electrode–electrolyte interface for electrosynthesis

Impact of curcumin on the pharmacokinetics of rosuvastatin in rats and dogs based on the conjugated metabolites

<p>1. Plasma concentrations of curcumin-O-glucuronide (COG) and curcumin-O-sulfate (COS) significantly increased after Sprague-Dawley rats dealt with the Oatp inhibitor rifampicin, with the <i>C</i>_max ascending 2.9 and 6.7 times, and the AUC_0–∞ ascending 4.4 and 10.8 times, respectively. When pretreated with the Oat inhibitor probenecid, the <i>C</i>_max increased 4.4 and 20 times, and the AUC_0–∞ increased 3.2 and 13.9 times, respectively. The results suggested that COG and COS may be the substrates of Oatp and Oat.</p> <p>2. The accumulation of curcumin significantly increased in organic anion transporting polypeptide (OATP)- and organic anion transporter (OAT)-transfected human embryonic kidney (HEK) 293 systems, which suggested that curcumin was a substrate of OATP1B1, OATP1B3, OATP2B1, OAT1, and OAT3; and COG was a substrate of OATP1B1, OATP1B3, and OAT3.</p> <p>3. Inhibition study using rosuvastatin as the substrate in OATP1B1- and OATP1B3-transfected cells indicated that curcumin was an OATP1B1 and 1B3 inhibitor, with IC₅₀ at 5.19 ± 0.05 and 3.68 ± 0.05 μM, respectively; the data for COG were 1.04 ± 0.01 and 1.08 ± 0.02 μM, respectively. COS was speculated to be an inhibitor of hepatic OATP1B1 as calculated using the ADMET Predictor.</p> <p>4. COG and COS are substrates and inhibitors of OATP/Oatp. Co-administration of curcumin significantly increased rosuvastatin concentration in rat and dog plasma.</p

Systematic Identification of Proteins Binding with Cisplatin in Blood by Affinity Chromatography and a Four-Dimensional Proteomic Method

Cisplatin is widely used for the treatment of various solid tumors. It is mainly administered by intravenous injection, and a substantial amount of the drug will bind to plasma proteins, a feature that is closely related to its pharmacokinetics, activity, toxicity, and side effects. However, due to the unique properties of platinum complexes and the complexity of the blood proteome, existing methods cannot systematically identify the binding proteome of cisplatin in blood. In this study, high-abundance protein separation and an ion mobility mass spectrometry-based 4D proteomic method were combined to systematically and comprehensively identify the binding proteins of cisplatin in blood. The characteristic isotope patterns of platinated peptides and a similarity algorithm were utilized to eliminate false-positive identification. Finally, 39 proteins were found to be platinated. Bioinformatics analysis showed that the identified proteins were mainly involved in the complement and coagulation cascade pathways. The binding ratio of some peptides with cisplatin was measured based on the area ratio of the free peptide using the parallel reaction monitoring method. This study provides a new method for systematically identifying binding proteins of metal drugs in blood, and the identified proteins might be helpful for understanding the toxicity of platinum anticancer drugs

Capillary LC Coupled with High-Mass Measurement Accuracy Mass Spectrometry for Metabolic Profiling

We have developed an efficient and robust high-pressure capillary LC−MS method for the identification of large numbers of metabolites in biological samples using both positive and negative ESI modes. Initial efforts focused on optimizing the separation conditions for metabolite extracts using various LC stationary phases in conjunction with multiple mobile-phase systems, as applied to the separation of 45 metabolite standards. The optimal mobile and stationary phases of those tested were determined experimentally (in terms of peak shapes, theoretical plates, retention of small, polar compounds, etc.), and both linear and exponential gradients were applied in the study of metabolite extracts from the cyanobacterium Cyanothece sp. ATCC 51142. Finally, an automated dual-capillary LC system was constructed and evaluated for the effectiveness and reproducibility of the chromatographic separations using the above samples. When coupled with a commercial LTQ-orbitrap MS, ∼900 features were reproducibly detected from Cyanothece sp. ATCC 51142 metabolite extracts. In addition, 12 compounds were tentatively identified, based on accurate mass, isotopic distribution, and MS/MS information

Ultrastable Iodinated Oil-Based Pickering Emulsion Enables Locoregional Sustained Codelivery of Hypoxia Inducible Factor‑1 Inhibitor and Anticancer Drugs for Tumor Combination Chemotherapy

Tumor hypoxia-associated drug resistance presents a major challenge for cancer chemotherapy. However, sustained delivery systems with a high loading capability of hypoxia-inducible factor-1 (HIF-1) inhibitors are still limited. Here, we developed an ultrastable iodinated oil-based Pickering emulsion (PE) to achieve locally sustained codelivery of a HIF-1 inhibitor of acriflavine and an anticancer drug of doxorubicin for tumor synergistic chemotherapy. The PE exhibited facile injectability for intratumoral administration, great radiopacity for in vivo examination, excellent physical stability (>1 mo), and long-term sustained release capability of both hydrophilic drugs (i.e., acriflavine and doxorubicin). We found that the codelivery of acriflavine and doxorubicin from the PE promoted the local accumulation and retention of both drugs using an acellular liver organ model and demonstrated significant inhibition of tumor growth in a 4T1 tumor-bearing mouse model, improving the chemotherapeutic efficacy through the synergistic effects of direct cytotoxicity with the functional suppression of HIF-1 pathways of tumor cells. Such an iodinated oil-based PE provides a great injectable sustained delivery platform of hydrophilic drugs for locoregional chemotherapy

Capillary LC Coupled with High-Mass Measurement Accuracy Mass Spectrometry for Metabolic Profiling

We have developed an efficient and robust high-pressure capillary LC−MS method for the identification of large numbers of metabolites in biological samples using both positive and negative ESI modes. Initial efforts focused on optimizing the separation conditions for metabolite extracts using various LC stationary phases in conjunction with multiple mobile-phase systems, as applied to the separation of 45 metabolite standards. The optimal mobile and stationary phases of those tested were determined experimentally (in terms of peak shapes, theoretical plates, retention of small, polar compounds, etc.), and both linear and exponential gradients were applied in the study of metabolite extracts from the cyanobacterium Cyanothece sp. ATCC 51142. Finally, an automated dual-capillary LC system was constructed and evaluated for the effectiveness and reproducibility of the chromatographic separations using the above samples. When coupled with a commercial LTQ-orbitrap MS, ∼900 features were reproducibly detected from Cyanothece sp. ATCC 51142 metabolite extracts. In addition, 12 compounds were tentatively identified, based on accurate mass, isotopic distribution, and MS/MS information