Gram-Scale Mechanochemical Synthesis of Atom-Layer MoS2 Semiconductor Electrocatalyst via Functionalized Graphene Quantum Dots for Efficient Hydrogen Evolution.

The development of advanced and efficient synthetic methods is pivotal for the widespread application of 2D materials. In this study, a facile and scalable solvent-free mechanochemical approach is approached, employing graphene quantum dots (GQDs) as exfoliation agents, for the synthesis and functionalization of nearly atom-layered MoS2 nanosheets (ALMS). The resulting ALMS exhibits an ultrathin average thickness of 4 nm and demonstrates high solvent stability. The impressive yield of ALMS reached 63%, indicating its potential for scalable production of stable nanosheets. Remarkably, the ALMS catalyst exhibits excellent HER performance. Moreover, the ALMS catalyst showcases exceptional long-term durability, maintaining stable performance for nearly 200 h, underscoring its potential as a highly efficient and durable electrocatalyst. Significantly, the catalytic properties of ALMS are significantly influenced by ball milling production conditions. The GQD-assisted large-scale machinery synthesis pathway provides a promising avenue for the development of efficient and high-performance ultrathin 2D materials.

Isomerization Engineering of Oxygen-Enriched Carbon Quantum Dots for Efficient Electrochemical Hydrogen Peroxide Production.

Hydrogen peroxide (H2O2) has emerged as a kind of multi-functional green oxidants with extensive industrial utility. Oxidized carbon materials exhibit promises as electrocatalysts in the two-electron (2e-) oxygen reduction reaction (ORR) for H2O2 production. However, the precise identification and fabrication of active sites that selectively yield H2O2 present a serious challenge. Herein, a structural engineering strategy is employed to synthesize oxygen-doped carbon quantum dots (o-CQD) for the 2e- ORR. The surface electronic structure of the o-CQDs is systematically modulated by varying isomerization precursors, thereby demonstrating excellent electrocatalyst performance. Notably, o-CQD-3 emerges as the most promising candidate, showcasing a remarkable H2O2 selectivity of 96.2% (n = 2.07) at 0.68 V versus RHE, coupled with a low Tafel diagram of 66.95 mV dec-1. In the flow cell configuration, o-CQD-3 achieves a H2O2 productivity of 338.7 mmol gcatalyst -1 h-1, maintaining consistent production stability over an impressive 120-hour duration. Utilizing in situ technology and density functional theory calculations, it is unveil that edge sites of o-CQD-3 are facilely functionalized by C-O-C groups under alkaline ORR conditions. This isomerization engineering approach advances the forefront of sustainable catalysis and provides a profound insight into the carbon-based catalyst design for environmental-friendly chemical synthesis processes.

Synergistic Effects of Amine Functional Groups and Enriched-Atomic-Iron Sites in Carbon Dots for Industrial-Current-Density CO2 Electroreduction.

Metal phthalocyanine molecules with Me-N4 centers have shown promise in electrocatalytic CO2 reduction (eCO2R) for CO generation. However, iron phthalocyanine (FePc) is an exception, exhibiting negligible eCO2R activity due to a higher CO2 to *COOH conversion barrier and stronger *CO binding energy. Here, amine functional groups onto atomic-Fe-rich carbon dots (Af-Fe-CDs) are introduced via a one-step solvothermal molecule fusion approach. Af-Fe-CDs feature well-defined Fe-N4 active sites and an impressive Fe loading (up to 8.5 wt%). The synergistic effect between Fe-N4 active centers and electron-donating amine functional groups in Af-Fe-CDs yielded outstanding CO2-to-CO conversion performance. At industrial-relevant current densities exceeding 400 mA cm-2 in a flow cell, Af-Fe-CDs achieved >92% selectivity, surpassing state-of-the-art CO2-to-CO electrocatalysts. The in situ electrochemical FTIR characterization combined with theoretical calculations elucidated that Fe-N4 integration with amine functional groups in Af-Fe-CDs significantly reduced energy barriers for *COOH intermediate formation and *CO desorption, enhancing eCO2R efficiency. The proposed synergistic effect offers a promising avenue for high-efficiency catalysts with elevated atomic-metal loadings.

Correction: Liu et al. Rational Design of Nitrogen-Doped Carbon Dots for Inhibiting ß-Amyloid Aggregation. Molecules 2023, 28, 1451.

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Solvent Engineering of Oxygen-Enriched Carbon Dots for Efficient Electrochemical Hydrogen Peroxide Production.

The development of cost-effective and reliable metal-free carbon-based electrocatalysts has gained significant attention for electrochemical hydrogen peroxide (H2 O2 ) generation through a two-electron oxygen reduction reaction. In this study, a scalable solvent engineering strategy is employed to fabricate oxygen-doped carbon dots (O-CDs) that exhibit excellent performance as electrocatalysts. By adjusting the ratio of ethanol and acetone solvents during the synthesis, the surface electronic structure of the resulting O-CDs can be systematically tuned. The amount of edge active CO group was strongly correlated with the selectivity and activity of the O-CDs. The optimum O-CDs-3 exhibited extraordinary H2 O2 selectivity of up to 96.55% (n = 2.06) at 0.65 V (vs RHE) and achieved a remarkably low Tafel plot of 64.8 mV dec-1 . Furthermore, the realistic H2 O2 productivity yield of flow cell is measured to be as high as 111.18 mg h-1  cm-2 for a duration of 10 h. The findings highlight the potential of universal solvent engineering approach for enabling the development of carbon-based electrocatalytic materials with improved performance. Further studies will be undertaken to explore the practical implications of the findings for advancing the field of carbon-based electrocatalysis.

Rational Design of Nitrogen-Doped Carbon Dots for Inhibiting ß-Amyloid Aggregation.

The fibrillization and abnormal aggregation of ß-amyloid (Aß) peptides are commonly recognized risk factors for Alzheimer's disease (AD) brain, and require an effective strategy to inhibit the Aß deposition and treat AD. Herein, we designed and synthesized nitrogen-doped carbon dots (N-CDs) as an Aß-targeted probe, which exhibits the capacity of inhibiting the 1-42 Aß (Aß1-42) self-assembly in vitro. The N-CDs exhibited orange emission with an emission wavelength of 570 nm, which demonstrates their excellent optical properties with excitation-independent behavior. Meanwhile, the N-CDs have spherical morphologies with an average size of 2.2 nm, whose surface enriches the amino, carboxyl, and hydroxyl groups. These preparties are conducive to improving their biological water solubility and provide a large number of chemical bonds for further interaction with proteins. Contrary to this, the kinetic process, size evolutions, and morphologies changes of Aß1-42 were inhibited in the presence of N-CDs in the determination of a thioflavin T assay, dynamic light scattering, transmission electron microscope, etc. Finally, the safety application of N-CDs on Aß1-42-induced cytotoxicity was further demonstrated via in vitro cytotoxicity experiments. This work demonstrates the effective outcome of suppressing Aß aggregation, which provides a new view into the high-efficiency and low-cytotoxicity strategy in AD theranostics.

Classification and review of free PCR primer design software.

MOTIVATION: Polymerase chain reaction (PCR) has been a revolutionary biomedical advancement. However, for PCR to be appropriately used, one must spend a significant amount of effort on PCR primer design. Carefully designed PCR primers not only increase sensitivity and specificity, but also decrease effort spent on experimental optimization. Computer software removes the human element by performing and automating the complex and rigorous calculations required in PCR primer design. Classification and review of the available software options and their capabilities should be a valuable resource for any PCR application. RESULTS: This article focuses on currently available free PCR primer design software and their major functions (https://pcrprimerdesign.github.io/). The software are classified according to their PCR applications, such as Sanger sequencing, reverse transcription quantitative PCR, single nucleotide polymorphism detection, splicing variant detection, methylation detection, microsatellite detection, multiplex PCR and targeted next generation sequencing, and conserved/degenerate primers to clone orthologous genes from related species, new gene family members in the same species, or to detect a group of related pathogens. Each software is summarized to provide a technical review of their capabilities and utilities.

Femoral artery aneurysm with large hematoma from Pasteurella: case report and literature review.

BACKGROUND: Pasteurella multocida is a well-known gram-negative facultative anaerobe well known for its ability to cause soft tissue infections following animal bite or scratch. Here we present a case with mycotic aneurysm of the superficial femoral artery due to P. multocida infection. CASE PRESENTATION: A 62 year old male patient presented with worsening right leg pain and swelling. On examination, he was found to have profound swelling and erythema of the right medial thigh and tenderness to palpation. Computerized tomography showed findings suggestive of right femoral pseudoaneurysm with a large right medial thigh hematoma. Blood cultures grew P. multocida. Patient underwent emergent open resection of the mycotic aneurysm and vascular bypass surgery. Intraoperatively, the site was noted to be grossly infected with multiple pockets of pus which were drained and pus cultures grew P. multocida. The diagnosis of P. multocida bacteremia with right femoral mycotic aneurysm and thigh abscess was made. Patient received 6 weeks of intravenous ceftriaxone and recovered. CONCLUSION: Our case is the first report on infection of peripheral vessel with Pasteurella and highlights the importance of prompt surgical intervention and effective antibiotic treatment.

Construction of Co,N-Coordinated Carbon Dots for Efficient Oxygen Reduction Reaction.

For the sake of the oxygen reduction reaction (ORR) catalytic performance, carbon dots (CDs) doped with metal atoms have accelerated their local electron flow for the past few years. However, the influence of CDs doped with metal atoms on binding sites and formation mechanisms is still uncertain. Herein, Co,N-doped CDs were facilely prepared by the low-temperature polymerization-solvent extraction strategy from EDTA-Co. The influence of Co doping on the catalytic performance of Co-CDs was explored, mainly in the following aspects: first, the pyridinic N atom content of Co-CDs significantly increased from 4.2 to 11.27 at% compared with the CDs, which indicates that the Co element in the precursor is advantageous in forming more pyridinic-N-active sites for boosting the ORR performance. Second, Co-CDs are uniformly distributed on the surface of carbon black (CB) to form Co-CDs@CB by the facile hydrothermal route, which can expose more active sites than the aggregation status. Third, the highest graphite N content of Co-CDs@CB was found, by limiting the current density of the catalyst towards the ORR. Composite nanomaterials formed by Co and CB are also used as air electrodes to manufacture high-performance zinc-air batteries. The battery has good cycle stability and realizes stable charges and discharges under different current densities. The outstanding catalytic activity of Co-CDs@CB is attributed to the Co,N synergistic effect induced by Co doping, which pioneer a new metal doping mechanism for gaining high-performance electrocatalysts.

Responsive Emulsions Stabilized by Amphiphilic Supramolecular Graft Copolymers Formed in Situ at the Oil-Water Interface.

Amphiphilic supramolecular graft copolymers which can stabilize oil-in-water (o/w) emulsions and enable responsive demulsification were demonstrated in this study. Linear poly[( N, N-dimethylacrylmide)- stat-(3-acrylamidophenylboronic acid)] (PDMA- stat-PAPBA) copolymers with phenylboronic acid (PBA) groups and linear polystyrene homopolymers with cis-diol terminals (PS(OH)2) were synthesized by reversible addition-fragmentation chain transfer polymerization. By the homogenization of the biphasic mixtures of an alkaline water solution of PDMA- stat-PAPBA copolymer and a toluene solution of PS(OH)2 homopolymer, stable o/w emulsions could be generated, although neither PDMA- stat-PAPBA nor PS(OH)2 alone was able to stabilize the emulsion. It was verified that the dispersed oil droplets in the emulsions were stabilized by the amphiphilic PDMA- stat-PAPBA- g-PS supramolecular graft copolymers, which were formed in situ at the oil-water interface by the complexation between the lateral PBA groups of PDMA- stat-PAPBA and the diol terminals of PS(OH)2 during homogenization. These emulsions showed pH- and glucose-responsive demulsification because of the reversible B-O bonds between the PDMA- stat-PAPBA backbones and the PS side chains. The effects of polymer concentrations on emulsion formation were also investigated. The current study provides an alternative method for the facile preparation of responsive polymeric emulsifiers, which potentially may be extended to other polymer pairs containing PBA and cis-diol groups.

Phospholipase D2-dependent inhibition of the nuclear hormone receptor PPARgamma by cyclic phosphatidic acid.

Cyclic phosphatidic acid (1-acyl-2,3-cyclic-glycerophosphate, CPA), one of nature's simplest phospholipids, is found in cells from slime mold to humans and has a largely unknown function. We find here that CPA is generated in mammalian cells in a stimulus-coupled manner by phospholipase D2 (PLD2) and binds to and inhibits the nuclear hormone receptor PPARgamma with nanomolar affinity and high specificity through stabilizing its interaction with the corepressor SMRT. CPA production inhibits the PPARgamma target-gene transcription that normally drives adipocytic differentiation of 3T3-L1 cells, lipid accumulation in RAW264.7 cells and primary mouse macrophages, and arterial wall remodeling in a rat model in vivo. Inhibition of PLD2 by shRNA, a dominant-negative mutant, or a small molecule inhibitor blocks CPA production and relieves PPARgamma inhibition. We conclude that CPA is a second messenger and a physiological inhibitor of PPARgamma, revealing that PPARgamma is regulated by endogenous agonists as well as by antagonists.

TRPM1 (melastatin) expression is an independent predictor of overall survival in clinical AJCC stage I and II melanoma patients.

BACKGROUND: The expression of TRPM1 (melastatin) mRNA is an independent marker, as measured by radioactive in situ hybridization (RISH), of disease-free survival in primary cutaneous melanoma (PM). The aim of the study was to determine if chromogenic in situ hybridization (CISH) can reproduce results examining diagnostic and prognostic utility of TRPM1 mRNA expression in melanocytic proliferations as measured by RISH. METHODS: The expression of TRPM1 mRNA was detected by CISH in melanocytic nevi (MN, n = 61), PM (n = 145) and metastatic melanomas (MMs, n = 15). RESULTS: A progressive loss of TRPM1 was found moving from MN to PM to MM. The histologic stepwise model of melanoma progression revealed that loss of TRPM1 occurred at the transition of RGP PM to VGP PM. As a diagnostic marker, TRPM1 gradient loss showed 93.8% sensitivity and 52.4% specificity for PM. Loss of TRPM1 mRNA correlated with melanoma aggressiveness markers and was independent predictor of disease-free and overall survival. The corresponding survival curves for degree of melanoma pigmentation matched those for degree of loss of TPRM1 mRNA. CONCLUSION: Loss of TRPM1 mRNA expression appears to be a crucial event in the progression of melanoma to a more malignant, metastatic phenotype.

Dual responsive Pickering emulsions stabilized by constructed core crosslinked polymer nanoparticles via reversible covalent bonds.

In this study, pH- and glucose-responsive Pickering emulsions stabilized by core crosslinked polymer nanoparticles, which were constructed via reversible covalent bonds, were presented for the first time. Firstly, well-defined PDMA-b-PAPBA (poly(N,N-dimethylacrylamide)-b-poly(3-acrylamidophenylboronic acid)) diblock copolymers were synthesized via sequential reversible addition-fragmentation chain transfer (RAFT) polymerization reactions. By means of complexation of PBA units of PDMA-b-PAPBA with PVA in basic water, core crosslinked polymer nanoparticles (CCPNs) with a core-shell structure were formed. The PAPBA/PVA crosslinked network and PDMA acted as the core and shell, respectively. Because of the reversible B-O chemical bonds in the core, the as-produced CCPNs showed structural transitions in response to the external stimuli involving pH and glucose. Investigation of the interfacial activities revealed that CCPNs exhibited high emulsifying performances, and oil in water (o/w) Pickering emulsions could be formed at a low particle content. The formed Pickering emulsions showed high stability at room temperature without any disturbances, whereas de-emulsification was observed upon improving the pH or adding glucose at a given pH. This is the first report on a responsive Pickering emulsion whose stability can be manipulated by glucose, and this type of fabricated manipulative Pickering emulsions are expected to provide useful guidance in the fields of oil recovery, interfacial reactions, etc.

Aminated graphene quantum dots/CdS nanobelts for enhanced photocatalytic degradation of RhB dye under visible light.

CdS nanoparticles have wide applications as photocatalysts for degradation of organic pollutants, but due to their limited turnover number and off-pathway charge recombination processes, their degradation efficiency is low. Herein, aminated graphene quantum dots/CdS (GQDs/CdS) nanobelts were successfully fabricated by solvothermal and hydrothermal processes. The prepared GQDs/CdS were characterized by physical methods to investigate their structure, morphology, optical properties, specific surface area, element composition, and chemical state. GQDs/CdS materials promoted efficient charge separation, and showed high efficiency in the photocatalytic degradation of the organic dye Rhodamine B (RhB) under visible light. The degradation efficiency of RhB samples over 0.05 g of catalysts reached 97.40% after 150 min, a much higher efficiency in comparison to pure CdS. Electron paramagnetic resonance (EPR) spectroscopy provided direct evidence for ˙OH and ˙O2- as the reactive oxidative species using DMPO as a spin trap. Consistent with the experimental results, a possible mechanism of RhB photocatalytic degradation by GQDs/CdS under visible light was proposed. This work may provide environmentally friendly photocatalysts for degrading organic dyes and purifying water.

Amine-Functionalized Metal-Free Nanocarbon to Boost Selective CO2 Electroreduction to CO in a Flow Cell.

Highly efficient electrochemical CO2-to-CO conversion is a promising approach for achieving carbon neutrality. While nonmetallic carbon electrocatalysts have shown potential for CO2-to-CO utilization in H-type cells, achieving efficient conversion in flow cells at an industrial scale remains challenging. In this study, we present a cost-effective synthesis strategy for preparing ultrathin 2D carbon nanosheet catalysts through simple amine functionalization. The optimized catalyst, NCNs-2.5, demonstrates exceptional CO selectivity with a maximum Faradaic efficiency of 98% and achieves a high current density of 55 mA cm-2 in a flow cell. Furthermore, the catalyst exhibits excellent long-term stability, operating continuously for 50 h while maintaining a CO selectivity above 90%. The superior catalytic activity of NCNs-2.5 is attributed to the presence of amine-N active sites within the carbon lattice structure. This work establishes a foundation for the rational design of cost-effective nonmetallic carbon catalysts as sustainable alternatives to metals in energy conversion systems.

Halogen doped graphene quantum dots modulate TDP-43 phase separation and aggregation in the nucleus.

TDP-43 is implicated in the dynamic formation of nuclear bodies and stress granules through phase separation. In diseased states, it can further condense into pathological aggregates in the nucleus and cytoplasm, contributing to the onset of amyotrophic lateral sclerosis. In this study, we evaluate the effect of graphene quantum dots (GQDs) with different functional groups on TDP-43's phase separation and aggregation in various cellular locations. We find that halogen atom-doped GQDs (GQDs-Cl, Cl-GQDs-OH) penetrate the nuclear envelope, inhibiting the assembly of TDP-43 nuclear bodies and stress granules under oxidative stress or hyperosmotic environments, and reduce amyloid aggregates and disease-associated phosphorylation of TDP-43. Mechanistic analysis reveals GQDs-Cl and Cl-GQDs-OH modulate TDP-43 phase separation through hydrophobic and electrostatic interactions. Our findings highlight the potential of GQDs-Cl and Cl-GQDs-OH in modulating nuclear protein condensation and pathological aggregation, offering direction for the innovative design of GQDs to modulate protein phase separation and aggregation.

Machine learning-guided realization of full-color high-quantum-yield carbon quantum dots.

Carbon quantum dots (CQDs) have versatile applications in luminescence, whereas identifying optimal synthesis conditions has been challenging due to numerous synthesis parameters and multiple desired outcomes, creating an enormous search space. In this study, we present a novel multi-objective optimization strategy utilizing a machine learning (ML) algorithm to intelligently guide the hydrothermal synthesis of CQDs. Our closed-loop approach learns from limited and sparse data, greatly reducing the research cycle and surpassing traditional trial-and-error methods. Moreover, it also reveals the intricate links between synthesis parameters and target properties and unifies the objective function to optimize multiple desired properties like full-color photoluminescence (PL) wavelength and high PL quantum yields (PLQY). With only 63 experiments, we achieve the synthesis of full-color fluorescent CQDs with high PLQY exceeding 60% across all colors. Our study represents a significant advancement in ML-guided CQDs synthesis, setting the stage for developing new materials with multiple desired properties.

Engineering Built-In Electric Field Microenvironment of CQDs/g-C3N4 Heterojunction for Efficient Photocatalytic CO2 Reduction.

Graphitic carbon nitride (CN), as a nonmetallic photocatalyst, has gained considerable attention for its cost-effectiveness and environmentally friendly nature in catalyzing solar-driven CO2 conversion into valuable products. However, the photocatalytic efficiency of CO2 reduction with CN remains low, accompanied by challenges in achieving desirable product selectivity. To address these limitations, a two-step hydrothermal-calcination tandem synthesis strategy is presented, introducing carbon quantum dots (CQDs) into CN and forming ultra-thin CQD/CN nanosheets. The integration of CQDs induces a distinct work function with CN, creating a robust interface electric field after the combination. This electric field facilitates the accumulation of photoelectrons in the CQDs region, providing an abundant source of reduced electrons for the photocatalytic process. Remarkably, the CQD/CN nanosheets exhibit an average CO yield of 120 µmol g-1, showcasing an outstanding CO selectivity of 92.8%. The discovery in the work not only presents an innovative pathway for the development of high-performance photocatalysts grounded in non-metallic CN materials employing CQDs but also opens new avenues for versatile application prospects in environmental protection and sustainable cleaning energy.

Amide Covalent Bonding Engineering in Heterojunction for Efficient Solar-Driven CO2 Reduction.

Inefficient charge separation and slow interfacial reaction dynamics significantly hamper the efficiency of photocatalytic CO2 reduction. Herein, a facile EDC/NHS-assisted linking strategy was developed to enhance charge separation in heterojunction photocatalysts. Using this approach, we successfully synthesized amide-bonded carbon quantum dot-g-C3N4 (CQD-CN) heterojunction photocatalysts. The formation of amide covalent bonds between CN and CQDs in the CN-CQD facilitates efficient carrier migration, CO2 adsorption, and activation. Exploiting these advantages, the CN-CQD photocatalysts exhibit high selectivity with CO and CH4 evolution rates of 79.2 and 2.7 µmol g-1 h-1, respectively. These rates are about 1.7 and 3.6 times higher than those of CN@CQD and bulk CN, respectively. Importantly, the CN-CQD photocatalysts demonstrate exceptional stability, even after 12 h of continuous testing. The presence of the COOH* signal is identified as a crucial intermediate species in the conversion of CO2 to CO. This study presents a covalent bonding engineering strategy for developing high-performance heterojunction photocatalysts for efficient solar-driven reduction of CO2.

Surface state engineering of carbon dot/carbon nanotube heterojunctions for boosting oxygen reduction performance.

Platinum-based (Pt) catalysts are the most common commercial catalysts for oxygen reduction reactions (ORR). Unfortunately, their high price, scarcity and poor durability hinder their further development. Therefore, the development of effective and economical ORR electrocatalysts has received increasing attention. Here, carbon dots (CDs) enriched in amino functional groups were successfully loaded onto carbon nanotubes (CNTs) with a large surface area and helical structure through a surface state engineering strategy. The resulting composites (CD/CNTs) are 0D/1D nano heterojunction structures. The CD/CNTs showed superior ORR activity compared with CNTs and CDs (Eoneset = 0.95 V, E1/2 = 0.81 V and limiting current density = 4.74 mA cm-2). In addition, the stability of CD/CNTs in an alkaline medium was up to 30000 s. The excellent ORR performance of CD/CNTs can be attributed to the dominant role of amino-N, the synergistic effect of heterojunctions formed by CDs and CNTs, and the high Lewis basicity. The composite electrocatalyst synthesized by the CD-regulated CNT strategy is expected to be a reliable cathode candidate for future energy conversion devices.