Low Selectivity Research Articles

Efficacy of bentonite/iron-coated sand as a sediment stabilizer in controlling cadmium, lead, zinc, and arsenic release determined using the diffusive gradients in thin film technology.

In this study, we investigated the efficiency of a bentonite/iron-coated sand (B/ICS) stabilizer in reducing the mobility and accumulation of heavy metals (Pb, Cd, Zn, and As) in contaminated sediments. Bentonite is effective in the adsorption of heavy metals, while ICS is effective in the adsorption of As. When combined, the stabilizer can be applied to mixed-contaminated sediments containing both heavy metals and As. The experimental setup involved B/ICS with sediments, followed by the analysis of heavy metal accumulation using diffusive gradients in thin-film resin gels for a period of 28days. The results obtained showed significant decreases in Pb, Cd, and Zn accumulation owing to the use of the stabilizer, particularly when its concentration was 15% of the sediment. Conversely, As accumulation did not show a decreasing trend owing to the low selectivity of the resin gel for As. Regardless, at the end of the 28-day test period, vertical distribution analysis indicated a notable decrease in heavy metal concentrations in the stabilizer layer of the contaminated sediment. These findings indicated that B/ICS is a cost-effective and efficient stabilizer for reducing heavy metal mobility in sediments. Long-term experiments are recommended to further validate these findings and optimize the use of the stabilizer in the field.

Periodically poled aluminum scandium nitride bulk acoustic wave resonators and filters for communications in the 6G era

Bulk Acoustic Wave (BAW) filters find applications in radio frequency (RF) communication systems for Wi-Fi, 3G, 4G, and 5G networks. In the beyond-5G (potential 6G) era, high-frequency bands (>8 GHz) are expected to require resonators with high-quality factor (Q) and electromechanical coupling (kt2) to form filters with low insertion loss and high selectivity. However, both the Q and kt2 of resonator devices formed in traditional uniform polarization piezoelectric films of aluminum nitride (AlN) and aluminum scandium nitride (AlScN) decrease when scaled beyond 8 GHz. In this work, we utilized 4-layer AlScN periodically poled piezoelectric films (P3F) to construct high-frequency (~17–18 GHz) resonators and filters. The resonator performance is studied over a range of device geometries, with the best resonator achieving a kt2 of 11.8% and a Qp of 236.6 at the parallel resonance frequency (fp) of 17.9 GHz. These resulting figures-of-merit are (FoM1=kt2Qp and FoM2=fpFoM1×10−9) 27.9 and 500, respectively. These and the kt2 are significantly higher than previously reported AlN/AlScN-based resonators operating at similar frequencies. Fabricated 3-element and 6-element filters formed from these resonators demonstrated low insertion losses (IL) of 1.86 and 3.25 dB, and −3 dB bandwidths (BW) of 680 MHz (fractional BW of 3.9%) and 590 MHz (fractional BW of 3.3%) at a ~17.4 GHz center frequency. The 3-element and 6-element filters achieved excellent linearity with in-band input third-order intercept point (IIP3) values of +36 and +40 dBm, respectively, which are significantly higher than previously reported acoustic filters operating at similar frequencies.

Surface curvature-driven adsorption-reduction mechanism over hollow N-doped carbon enhances recovery of precious metal ions from wastewater.

The recovery of precious metal ions (PMI) from wastewater has great significances from both economic and environmental perspectives. However, current recovery methods face limitations, including low efficiency and selectivity, as well as challenges in practical applications. In this study, hollow N-doped carbon spheres (HNC) are proved to be promising for improving anionic AuCl4- and PdCl42- recovery via the curvature effect, outperforming non-curved carbon (commercial active carbon and carbon nanosheet) due to their unique curvature effect. The maximum recovery capacities of HNC for AuCl4- and PdCl42- reach as high as 304.90 mg·g -1 and 84.31 mg·g -1 (calculated as metallic elements), far exceeding those of activated carbon (175.9 mg·g -1 for Au and 46.87 mg·g -1 for Pd) and carbon nanosheet (33.92 mg·g -1 for Au and 4.33 mg·g -1 for Pd). The recovery processes of HNC could reach equilibrium within 1 h, exhibiting a rapid recovery kinetic process. The superior recovery performance of HNC can be attributed to the adsorption-reduction mechanism. The convex surface of HNC concentrates a lot of electrons due to the curvature effect, facilitating the electron transfer from HNC to PMI. The key reduction process is thus induced on the electron-rich outer surface of the sphere. Remarkably, the increased curvatures significantly boost the PMI recovery, further confirming the importance of curvature effect. In addition, HNC materials exhibit superior anti-interference ability against co-existing ions and potential practicability. Therefore, innovative adsorption-reduction mechanism and curvature effect are proposed, which offer a new prospect in developing cost-effective recovery technology of precious metals and environmental remediation.

Affinity descriptor of metal catalysts: concept, measurement and application of oxygen affinity in the catalytic transformation of oxygenates.

Multiple oxygenate groups in biomass-based feedstocks are open to multiple catalytic pathways and products, typically resulting in low selectivity for the desired products. In this context, strategies for rational catalyst design are critical to obtain high selectivity for the desired products in biomass upgrading. The Sabatier principle provides a conceptual framework for designing optimal catalysts by following the volcanic relationship between catalyst activity for a reaction and the binding strength of a substrate on a catalyst. The affinity descriptor of catalysts, which scales the interaction strength of the functional groups of substrates with catalysts, can potentially be developed to correlate with catalyst performance in reactions. Specifically, the oxygen affinity of catalysts, as a measure of the interaction strength between oxygenates and catalysts, can be applied to rationalize the oxygenate transformation and guide the rational design of efficient catalysts based on the Sabatier principle. This review highlights the fundamental basis and applications of affinity descriptors in catalysis, with a focus on the oxygen affinity of catalysts for the transformation of biomass-derived oxygenate compounds.

Establishment of Gas-Liquid-Solid Interface on Multilevel Porous Cu2O for Potential-Driven Selective CO2 Electroreduction toward C1 or C2 Products.

Copper-based catalysts demonstrate distinctive multicarbon product activity in the CO2 electroreduction reaction (CO2RR); however, their low selectivity presents significant challenges for practical applications. Herein, we have developed a multilevel porous spherical Cu2O structure, wherein the mesopores are enriched with catalytic active sites and effectively stabilize Cu+, while the macropores facilitate the formation of a "gas-liquid-solid" three-phase interface, thereby creating a microenvironment with an increasing water concentration gradient from the interior to the exterior. Potential-driven phase engineering and protonation synergistically optimize the reaction pathway, facilitating a switch between CO and C2H4. At a low current density of 100 mA cm-2, the faradaic efficiency (FE) for CO reaches an impressive 96.97%. When the current density increases to 1000 mA cm-2, FEC2H4 attains 53.05%. Experiments and theoretical calculations indicate that at lower potentials, the pure Cu2O phase diminishes the adsorption of *CO intermediates, while weak protonation inhibits hydrogen evolution reactions, thereby promoting CO production. Conversely, at more negative potentials, the Cu0/Cu+ interface and strong protonation generate locally elevated concentrations of *CO and *COOH intermediates, which enhance C-C coupling and deep hydrogenation, ultimately improving selectivity toward C2+ products. This study provides novel insights into the rational design of copper-based catalysts for customizable CO2 electroreduction products.

Combination of FeII-O Species and Fe-O-Zr Bonds Empowers FeOx Nanoclusters Anchored on UiO-66 Robust H2S-Selective Catalytic Oxidation Performance.

The low sulfur selectivity of Fe-based H2S-selective catalytic oxidation catalysts is still a problem, especially at a high O2 content. This is alleviated here through anchoring FeOx nanoclusters on UiO-66 via the formation of Fe-O-Zr bonds. The introduced FeOx species exist in the form of FeIII and FeII. Therein the FeIII-O species are the predominant active sites for H2S-oxidation. The formed Fe-O-Zr bonds strengthen the redox cycle of FeIII/FeII through promoting electron transfer from Fe to Zr. The FeII-O species can activate molecular oxygen to oxidize H2S into elemental S, which accelerates the formation rate of atomic S, hindering its further oxidation into SO2. The combination of these factors empowers the catalysts, enabling 100% H2S conversion and 98.2% sulfur yield. The catalyst also has satisfactory stability with the sulfur selectivity only decreasing from 98.2% to 91.3% after the reaction going on 50 h. The decreased sulfur selectivity might be caused by the deterioration of pores and the deposition of elemental S on the surface. The former hinders the diffusion of sulfur oligomers timely from pores to the gas phase, while the latter is suspected to capture electrons to promote its further reaction with molecular oxygen.

A highly sensitive and fast-response fluorescence nanoprobe for in vivo imaging of hypochlorous acid.

Fluorescent probes for in vivo hypochlorous acid (HClO) imaging often face challenges of low selectivity and high cytotoxicity, largely due to poor analyte recognition and water-insoluble aromatic skeletons. To address this, we synthesized fluorescein hydrazide by introducing a spiro-lactam unit into fluorescein, which offers high emission intensity and molar absorption. The five-membered heterocycle in fluorescein hydrazide is selectively disrupted by HClO, enhancing the conjugated system and electron delocalization of the fluorophore, resulting in highly sensitive fluorescence detection of HClO. For in vivo imaging, fluorescein hydrazide was covalently grafted onto the surface of silica nanoparticles via nucleophilic substitution reaction, avoiding complex modifications. This fluorescent nanoprobe (Si-FL) leverages the high-density fluorophores and hydroxyl groups on the silica surface to enrich low-concentrations of HClO through weak supramolecular interactions, thereby accelerating the reaction between HClO and the recognition sites. Compared to other molecular probes, Si-FL demonstrates a superior response speed (within 20 s) and a lower detection limit (72 nM), alongside excellent biocompatibility and water solubility. The nanoprobe Si-FL was successfully applied for HClO detection in living cells, zebrafish, and plants, significantly improving the stability of fluorescence imaging.

Light-induced Enhancement of Energetic Charge Carrier Extraction and Modulation of Local Charge Density to Impact Selectivity in Plasmonic Nanometals.

Localized surface plasmon resonance (LSPR) metals exhibit remarkable light-absorbing property and unique catalytic activity, attracting significant attention in photocatalysts recently. However, the practical application of plasmonic nanometal is hindered by challenge of energetic electrons extraction and low selectivity. The energetic carriers generated in nanometal under illumination have extremely short lifetimes, leading to rapid energy loss. In this work, silver nanometals modified with five distinct sulfhydryl ligands (re-Ag-S-R) were synthesized via photoreduction of superlattice precursors. Modified surface efficiently extracts and preserves excited state electrons of plasmonic nanometals. By modulation the local charge density at catalytic active sites through substituents with varying electron-donating and electron-withdrawing properties, the selectivity of the photocatalytic carbon dioxide reduction reaction and hydrogen evolution reaction was influenced. The results demonstrated opposite selectivity between methoxy-modified re-Ag-S-OCH3 (CO selectivity of 96.73%) and amino-modified re-Ag-S-NH2 (H2 selectivity of 96.66%) despite their similar structures. The changes in excited states and surface contact potentials induced by LSPR were monitored using femtosecond transient absorption (fs-TA) spectroscopy and Kelvin probe force microscopy (KPFM). Meanwhile, the detailed discussion of the LSPR mechanism in plasmonic nanometals will serve as valuable references and foundational elements for future research in this area.

Revolutionizing radiotherapy: gold nanoparticles with polyphenol coating as novel enhancers in breast cancer cells—an in vitro study

Breast cancer is the most common cancer among women, with over 1 million new cases and around 400,000 deaths annually worldwide. This makes it a significant and costly global health challenge. Standard treatments like chemotherapy and radiotherapy, often used after mastectomy, show varying effectiveness based on the cancer subtype. Combining these treatments can improve outcomes, though radiotherapy faces limitations such as radiation resistance and low selectivity for malignant cells. Nanotechnologies, especially metallic nanoparticles (NPs), hold promise for enhancing radiotherapy. Gold nanoparticles (AuNPs) are particularly notable due to their high atomic number, which enhances radiation damage through the photoelectric effect. Studies shown that AuNPs can act as effective radiosensitizers, improving tumor damage during radiotherapy increasing the local radiation dose delivered. Traditional AuNPs synthesis methods involve harmful chemicals and extreme conditions, posing health risks. Green synthesis methods using plant extracts offer a safer and more environmentally friendly alternative. This study investigates the synthesis of AuNPs using Laurus nobilis leaf extract and their potential as radiosensitizers in breast carcinoma cell lines (MCF-7). These cells were exposed to varying doses of X-ray irradiation, and the study assessed cell viability, morphological changes and DNA damage. The results showed that green-synthesized AuNPs significantly enhanced the therapeutic effects of radiotherapy at lower radiation doses, indicating their potential as a valuable addition to breast cancer treatment.

Synergistic Effects in a Nitrogen‐Coordinated Zinc Single‐Atom Catalyst for Efficient CO2 Cycloaddition

AbstractThe valorization of CO2 into organic carbonates through its cycloaddition to epoxides has garnered significant attention in catalysis. However, the reaction is often hindered by low selectivity, and a key challenge is the development of catalysts capable of effectively activating both CO2 and epoxides simultaneously. In this study, we prepared and characterized a catalyst comprising isolated zinc single atoms dispersed on carbon nitride for the selective CO2 conversion to cyclic carbonates. The monoatomic nature and homogeneous distribution of the zinc species were confirmed utilizing advanced characterization methods, including X‐ray absorption spectroscopy and aberration‐corrected scanning transmission electron microscopy. The catalyst activity and recyclability were validated through catalytic tests with epichlorohydrin as a model epoxydic compound, and the study scope was subsequently extended to include a wide range of functionalized epoxides. Density functional theory calculations were performed to elucidate the reaction mechanism, revealing that both CO2 and epichlorohydrin interact with the same zinc atom in the cycloaddition process, highlighting the key role of zinc single atoms in promoting the reaction. Overall, the present study provides new insights into the design and optimization of heterogeneous catalysts for CO2 cycloadditions, paving the way for more effective strategies in CO2 valorization and conversion for producing valuable fine chemicals.

A Hexavalent Tellurium-Based Chalcogen Bonding Catalysis Platform: High Catalytic Activity and Controlling of Selectivity.

Herein, we describe a hexavalent tellurium-based chalcogen bonding catalysis platform capable of addressing reactivity and selectivity issues. This research demonstrates that hexavalent tellurium salts can serve as a class of highly active chalcogen bonding catalysts for the first time. The tellurium centers in these hexavalent catalysts have only one exposed interaction site, thus providing a favorable condition for the controlling of reaction selectivity. The advantages of these hexavalent tellurium catalysts were demonstrated by their remarkable catalytic activity in the cyanidation of difluorocyclopropenes through C-F bond activation, which otherwise were low reactive under the catalysis of strong Lewis acids or inaccessible by representative divalent/tetravalent tellurium-based donors. The catalytic activity of the hexavalent tellurium catalyst was further highlighted by its capability to address a previously unresolved reactivity problem associated with the strong Lewis acid approach, upon using some less reactive silyl enol ethers as nucleophiles in the functionalization of difluorocyclopropenes. The generality of this catalysis platform was demonstrated by its versatile application in different reaction systems. The hexavalent tellurium catalyst can differentiate two similar free OH groups in glycosyl acceptors to achieve excellent regio- and stereoselectivity in the synthesis of disaccharides, in which the tetravalent tellurium catalyst gave low reactivity and selectivity. Mechanistic investigation suggests that a catalyst-glycosyl donor-acceptor ternary supramolecular complex is operative.

Unravelling the aromatic symphony: redirecting bifunctional mushroom synthases towards linalool monofunctionality

Enzymes are the cornerstone of biocatalysis, biosynthesis and synthetic biology. However, their applicability is often limited by low substrate selectivity. A prime example is the bifunctional linalool/nerolidol synthase (LNS) that can use both geranyl diphosphate (GPP) and farnesyl diphosphate (FPP) to produce linalool and nerolidol, respectively. This bifunctionality can lead to undesired byproducts in synthetic biology applications. To enhance enzyme specificity and create monofunctional linalool synthases, we modified amino acids in the loop between helices C and D of four bifunctional mushroom LNSs. Through these modifications, we successfully shifted the substrate preference of two LNSs (ApLNS from Agrocybe pediades and HsLNS from Hypholoma sublateritium) from FPP towards GPP. Although complete monofunctionality was not achieved, we significantly increased linalool yield by 13 times while minimizing nerolidol production to 1% of the wildtype HsLNS. Docking simulations revealed a substantial reduction in the FPP binding score compared to that of the wildtype. Molecular dynamics simulations suggested that Tyr300 in the apo HsLNS mutant has a greater tendency to adopt an inward orientation. Together with Met77, the inward-facing Tyr300 creates a steric barrier that prevents the longer FPP molecule from entering the substrate binding pocket, thereby greatly reducing its activity towards FPP. This study demonstrates the potential of enzyme engineering to design substrate-specific terpene synthases, which is a challenging task and few successful examples are available. The insights gained can inform future enzyme design efforts, including the development of artificial intelligence models.

Striking Improvement of N2 Selectivity in NH3 Oxidation Reaction on Fe2O3-Based Catalysts via SiO2 Doping.

The emission of NH3 has been reported to pose a serious threat to both human health and the environment. To efficiently eliminate NH3, catalysts for the selective catalytic oxidation of NH3 (NH3-SCO) have been intensively studied. Fe2O3-based catalysts were found to exhibit superior NH3 oxidation activity; however, the low N2 selectivity made it less attractive in practical applications. In this work, aimed at improving the N2 selectivity on Fe2O3-based catalysts, a simple SiO2 doping strategy was proposed. Although the NH3 oxidation activity showed almost no change on Fe2O3 after SiO2 doping, the N2 selectivity was significantly improved. Systematic characterizations revealed that SiO2 doping could increase the specific surface area of Fe2O3, and a strong interaction of Fe-O-Si was formed in Fe2O3-SiO2 mixed oxide catalysts. Furthermore, abundant Brønsted acid sites were formed on Fe2O3-SiO2 catalysts due to the facile hydrolysis of the Fe-O-Si structure into Si-OH and Fe-OH. Although SiO2 doping was found to weaken the redox ability of Fe2O3, the abundant Brønsted acid sites on Fe2O3-SiO2 catalysts could facilitate NH3 oxidation reaction through an internal SCR (i-SCR) pathway, thus achieving superior N2 selectivity. This work can provide new insights into constructing efficient NH3-SCO catalysts with high N2 selectivity.

Synergistic Effect Promotes Visible‐Light–Driven CO2‐To‐CO Conversion by Macrocyclic Dinuclear Mixed‐Valence Co (II)/Co (III) Complexes

ABSTRACTThe catalytic conversion of carbon dioxide (CO2) into valuable energy under light sources is one of the effective ways to achieve carbon cycle. The reported nonprecious metal complex catalysts still show the shortcomings of low catalytic activity and low selectivity in visible‐light–driven CO2 reduction, especially in aqueous systems. Herein, we report three dinuclear mixed‐valence Co (II)/Co (III) complexes 1–3 bearing macrocyclic ligands that exhibit high activity and selectivity for visible‐light–driven photocatalytic CO2 reduction in an aqueous system. Moreover, the TONCO and CO selectivity for macrocyclic dinuclear mixed‐valence complex 3 reach as high as 4100 and 96%, respectively, which is about 4.9 times higher than that of mononuclear Co (II) complex 4. Through electrochemical and DFT calculations, we found that the increase in photocatalytic activity of 3 is due to the synergistic effect between the two metal centers, in which one Co site stabilizes the *COOH intermediate and reduces the energy barrier of the rate‐determining step, thereby increasing the catalytic activity.

A Smart mRNA-Initiated Theranostic Multi-shRNA Nanofactory for Precise and Efficient Cancer Gene Therapy.

Despite the significant potential of short hairpin RNA (shRNA)-mediated gene therapy for various diseases, the clinical success of cancer treatment remains poor, partly because of low selectivity and low efficiency. In this study, an mRNA-initiated autonomous multi-shRNA nanofactory (RNF@CM) is designed for in vivo amplification imaging and precise cancer treatment. The RNF@CM consists of a gold nanoparticle core, an interlayer of two types of three-stranded DNA/RNA hybrid probes, one of which is bound to aptamer-inhibited DNA polymerases, and an outer layer of the cancer cell membrane. After the specific delivery of RNF@CM into target cancer cells, an intracellular tumour-related mRNA target can initiate the RNF@CM with a circular strand-displacement polymerisation reaction, resulting in the release of significantly amplified fluorescence and continuous production of three types of shRNAs. The RNF@CM effectively distinguished cancer cells from normal cells, exclusively produced multiple shRNAs in response to a specific mRNA target in cancer cells, accurately diagnosed tumours in vivo, and significantly inhibited tumour growth with negligible toxicity, expanding the toolbox for on-demand gene delivery and precision theranostics.

Guanidines Conjugated with Cell-Penetrating Peptides: A New Approach for the Development of Antileishmanial Molecules.

Leishmaniasis is a neglected tropical disease caused by a protozoan of the genus Leishmania, which has visceral and cutaneous forms. The symptoms of leishmaniasis include high fever and weakness, and the cutaneous infection also causes lesions under the skin. The drugs used to treat leishmaniasis have become less effective due to the resistance mechanisms of the protozoa. In addition, the current compounds have low selectivity for the pathogen, leading to various side effects, which results in lower adherence to treatment. Various strategies were developed to solve this problem. The bioconjugation between natural compounds with antimicrobial activity and cell-penetrating peptides could alleviate the resistance and toxicity of current treatments. This work aims to conjugate the cell penetration peptide TAT to the guanidine GVL1. The GVL1-TAT bioconjugate exhibited leishmanicidal activity against Leishmania amazonensis and Leishmania infantum with a high selectivity index. In addition, the bioconjugate was more active against the intracellular enzyme CPP than the individual compounds. This target is very important for the viability and virulence of the parasite within the host cell. Docking studies confirmed the higher interaction of the conjugate with CPP and suggested that other proteins, such as trypanothione reductase, could be targeted. Thus, the data indicated that guanidines conjugated with cell-penetrating peptides could be a good approach for developing antileishmanial molecules.

Interfacial Oxygen Vacancy-Copper Pair Sites on Inverse CeO2/Cu Catalyst Enable Efficient CO2 Electroreduction to Ethanol in Acid.

Renewable electricity-driven electrochemical reduction of CO2 offers a promising route for production of high-value ethanol. However, the current state of this technology is hindered by low selectivity and productivity, primarily due to limited understanding of the atomic-level active sites involved in ethanol formation. Herein, we identify that the interfacial oxygen vacancy-neighboring Cu (Ov-Cu) pair sites are the active sites for CO2 electroreduction to ethanol. A linear correlation between the density of Ov-Cu pair sites and ethanol productivity is experimentally evidenced. Moreover, a high Faradaic efficiency of 48.5% and a partial current density of 344.0 mA cm-2 for ethanol production are achieved over the inverse CeO2/Cu catalyst with a high density of Ov-Cu pair sites in acid. Mechanistic studies that combine density functional theory calculations and spectroscopic techniques propose an Ov-involved mechanism where interfacial Ov sites directly activate and dissociate CO2 into *CO in a thermodynamically spontaneous manner, thus favoring the subsequent *CHO formation and asymmetric CHO-CO coupling. Besides, the asymmetric Ov-Cu pair sites could preferentially stabilize the *CH2CHOH intermediate, resulting in the favorable formation of ethanol over ethylene. Our findings provide new atomic-level insights into CO2 electroreduction to ethanol, paving the way for the rational design of future catalysts.

A Review on Branched-Chain Amino Acid Aminotransferase (BCAT) Inhibitors: Current Status, Challenges and Perspectives.

Branched-chain amino acids (BCAAs) are essential amino acids for humans and play an indispensable role in many physiological and pathological processes. Branched-chain amino acid aminotransferase (BCAT) is a key enzyme that catalyzes the metabolism of BCAAs. BCAT is upregulated in many cancers and implicated in the development and progress of some other diseases, such as metabolic and neurological diseases; and therefore, targeting BCAT might be a potential therapeutic approach for these diseases. There are two isoforms of BCAT, i.e., cytoplasmic BCAT1 (or BCATc) and mitochondrial BCAT2 (or BCATm). The discovery of BCAT inhibitors was initiated by Warner-Lambert, a subsidiary of Pfizer, in 2000, followed by many other pharmaceutical companies, such as GlaxoSmithKline (GSK), Ergon, Icagen, Agios, and Bayer. Strategies of high-throughput screening (HTS), DNA-Encoded library technology (ELT), and fragment-based screening (FBS) have been employed for hit identification, followed by structural optimization. Despite low selectivity, both BCAT1 and BCAT2 selective inhibitors were individually developed, each with a few chemical structural classes. The most advanced BCAT1 inhibitor is BAY-069, discovered by Bayer, which has a potent enzymatic inhibitory activity against BCAT1 and a decent in vitro and in vivo pharmacokinetic profile but displayed weaker cellular inhibitory activity and almost no anti-proliferative activity. There are no BCAT inhibitors currently under investigation in clinical trials. Further studies are still needed to discover BCAT inhibitors with a more druggable profile for proof of concept. This review focuses on the latest progress of studies on the understanding of the physiology and pathology of BCAT and the discovery and development of BCAT inhibitors. The structure-activity relationship (SAR) and the druggability, and the challenges of BCAT inhibitors are discussed, with the aim of inspiring the discovery and development of BCAT inhibitors in the future.

Bifunctional Pd-Pt Supported Nanoparticles for the Mild Hydrodeoxygenation and Oxidation of Biomass-Derived Compounds.

The conversion of bio-based molecules into valuable chemicals is essential for advancing sustainable processes and addressing global resource challenges. However, conventional catalytic methods often demand harsh conditions and suffer from low product selectivity. This study introduces a series of bifunctional PdxPty catalysts supported on TiO2, designed for achieving selective and mild-temperature catalysis in biomass conversion. Synthesized via a sol immobilization method and characterized by XRF, N2 physisorption, HRTEM, HAADF-STEM, and XPS, these catalysts demonstrate superior selectivity and activity over monometallic counterparts. In fact, at 20 bar H2, Pt/TiO2 show a low selectivity in benzophenone hydrodeoxygenation, favoring the benzhydrol hydrogenation product; similarly, Pd/TiO2 preferentially form the diphenylmethane hydrodeoxygenation (HDO) product, but with slow conversion rates. The synergistic combination of the two metals in Pd4Pt1/TiO2 drastically improve performance, with 100 % benzophenone conversion and 73 % diphenylmethane selectivity. DFT calculations confirm the synergy between Pd and Pt as the key to drive the activity and selectivity. Additionally, the catalysts also demonstrate high recyclability with minimal performance loss, and have been generalized for the HDO of vanillin and furfural, and in HMF oxidation. Overall, this work highlights the potential of bimetallic catalysts in enabling efficient and selective bio-based molecule conversion under mild conditions.

Electrocatalytic systems for NOx upgrading.

Chemical manufacturing utilizing renewable resources and energy presents a promising avenue toward sustainability and carbon neutrality. Electrocatalytic upgrading of nitrogen oxides (NOx) into nitrogenous chemicals is a potential strategy for synthesizing chemicals and mitigating NOx pollution. However, this approach is currently hindered by low selectivity and efficiency, limited reaction pathways, and economic challenges, primarily due to the development of suboptimal electrocatalytic systems for NOx upgrading. In this review, we focus on electrocatalytic systems for NOx upgrading and discuss newly developed components, including catalysts, solvents, electrolysers, and upstream/downstream processes. These advancements enable recent developments in NOx upgrading reactions that yield various products, including green ammonia (NH3), dinitrogen (N2), nitrogenous chemicals beyond NH3 and N2 (e.g., hydroxylamine and hydrazine), and organonitrogen compunds. Additionally, we provide an outlook to highlight future directions in the emerging field of novel electrocatalytic systems for NOx upgrading.