Regulating the electronic structure of Pt SAs-Ni2P for enhanced hydrogen evolution reaction.

The single atom catalysts (SACs) show immense promise as catalytic materials. By doping the single atoms (SAs) of precious metals onto substrates, the atomic utilization of these metals can be maximized, thereby reducing catalyst costs. The electronic structure of precious metal SAs is significantly influenced by compositions of doped substrates. Therefore, optimizing the electronic structure through appropriate doping of substrates can further enhance catalytic activity. Here, Pt single atoms (Pt SAs) are doped onto transition metal sulfide substrate NiS2 (Pt SAs-NiS2) and phosphide substrate Ni2P (Pt SAs-Ni2P) to design and prepare catalysts. Compared to the Pt SAs-NiS2 catalyst, the Pt SAs-Ni2P catalyst exhibits better hydrogen evolution catalytic performance and stability. Under 1 M KOH conditions, the hydrogen evolution mass activity current density of the Pt SAs-Ni2P catalyst reaches 0.225 A mgPt-1 at 50 mV, which is 33 times higher than that of commercial Pt/C catalysts. It requires only 44.9 mV to achieve a current density of 10 mA cm-2. In contrast, for the Pt SAs-NiS2 catalyst, the hydrogen evolution mass activity current density is 0.178 A mgPt-1, requiring 77.8 mV to achieve a current density of 10 mA cm-2. Theoretical calculations indicate that in Pt SAs-Ni2P, the interaction between Pt SAs and the Ni2P substrate causes the Pt d-band center to shift downward, enhancing the H2O desorption and providing optimal H binding sites. Additionally, the hollow octahedral morphology of Ni2P provides a larger surface area, exposing more reactive sites and improving reaction kinetics. This study presents an effective pathway for preparing high-performance hydrogen evolution electrocatalysts by selecting appropriate doped substrates to control the electronic structure of Pt SAs.

Recent Advances in Fluorescent Nanoparticles for Stimulated Emission Depletion Imaging.

Stimulated emission depletion (STED) microscopy, as a popular super-resolution imaging technique, has been widely used in bio-structure analysis and resolving the dynamics of biological processes beyond the diffraction limit. The performance of STED critically depends on the optical properties of the fluorescent probes. Ideally, the probe should process high brightness and good photostability, and exhibit a sensitive response to the depletion beam. Organic dyes and fluorescent proteins, as the most widely used STED probes, suffer from low brightness and exhibit rapid photobleaching under a high excitation power. Recently, luminescent nanoparticles (NPs) have emerged as promising fluorescent probes in biological imaging due to their high brightness and good photostability. STED imaging using various kinds of NPs, including quantum dots, polymer dots, carbon dots, aggregation-induced emission dots, etc., has been demonstrated. This review will comprehensively review recent advances in fluorescent NP-based STED probes, discuss their advantages and pitfalls, and outline the directions for future development.

Neuroprotective effect of acetoxypachydiol against oxidative stress through activation of the Keap1-Nrf2/HO-1 pathway.

BACKGROUND: Excessive oxidative stress in the brain is an important pathological factor in neurological diseases. Acetoxypachydiol (APHD) is a lipophilic germacrane-type diterpene extracted as a major component from different species of brown algae within the genus Dictyota. There have been no previous reports on the pharmacological activity of APHD. The present research aims to explore the potential neuroprotective properties of APHD and its underlying mechanisms. METHODS: The possible mechanism of APHD was predicted using a combination of molecular docking and network pharmacological analysis. PC12 cells were induced by H2O2 and oxygen-glucose deprivation/reoxygenation (OGD/R), respectively. Western blot, flow cytometry, immunofluorescence staining, and qRT-PCR were used to investigate the antioxidant activity of APHD. The HO-1 inhibitor ZnPP and Nrf2 gene silencing were employed to confirm the influence of APHD on the signaling cascade involving HO-1, Nrf2, and Keap1 in vitro. RESULTS: APHD exhibited antioxidant activity in both PC12 cells subjected to H2O2 and OGD/R conditions by downregulating the release of LDH, the concentrations of MDA, and ROS, and upregulating SOD, GSH-Px, and GSH concentrations. APHD could potentially initiate the Keap1-Nrf2/HO-1 signaling cascade, according to the findings from network pharmacology evaluation and molecular docking. Furthermore, APHD was observed to increase Nrf2 and HO-1 expression at both mRNA and protein levels, while downregulating the protein concentrations of Keap1. Both Nrf2 silencing and treatment with ZnPP reversed the neuroprotective effects of APHD. CONCLUSIONS: APHD activated antioxidant enzymes and downregulated the levels of LDH, MDA, and ROS in two cell models. The neuroprotective effect is presumably reliant on upregulation of the Keap1-Nrf2/HO-1 pathway. Taken together, APHD from brown algae of the genus Dictyota shows potential as a candidate for novel neuroprotective agents.

[Characteristics and Source Apportionment of VOCs Initial Mixing Ratio in Beijing During Summer].

To clarify the characteristics and source apportionment of the VOCs initial mixing ratio in Beijing in summer, continuous monitoring of VOCs was conducted in the Beijing urban area from May to August 2022, and the initial mixing ratio was calculated using the photochemical ratio method. The results showed that:① during the study period, initial φ(TVOCs) in the Beijing urban area were (30.0 ±11.5)×10-9, in which the proportion of VOCs and alkanes containing oxygen reached 34.2% and 33.2%, respectively. The species with high volume fractions were low carbon substances such as acetone, ethane, acetaldehyde, and propane. ② The initial TVOCs mixing ratio in Beijing showed a slightly unimodal trend, reaching the peak at 11:00 and slightly decreasing in the afternoon. ③ Isoprene, acetaldehyde, n-butanal, and ethylene were the major contributors to the generation of O3, whereas toluene, isoprene, m-paraxylene, and ethylbenzene were the major contributors to the generation of secondary organic aerosols. ④ Based on the initial mixing ratio of PMF analysis, it was found that aging background and secondary sources (30%) contributed the most to VOCs in Beijing, and motor vehicle sources (25%) were the main primary human sources. In addition, solvent and fuel volatile sources contributed 16%, combustion sources contributed 11%, industrial process sources contributed 9%, and natural sources contributed 9%. ⑤ The anthropogenic sources of Beijing were mainly from the eastern and southern regions, whereas the natural sources were from the western and northwestern regions. This research showed that vehicle emissions should be further reduced, and regional joint prevention and control to reduce VOCs in the whole region is an effective means to control VOCs in Beijing.

Tolerability, safety, and pharmacokinetics of a single intravenous administration of a novel recombinant humanized anti-interleukin-6 receptor monoclonal antibody in healthy Chinese volunteers.

Aim: VDJ001 is a novel recombinant humanized monoclonal antibody against the anti-interleukin-6 receptor. As an analog of tocilizumab, it exhibited improved affinity and in vitro activity. Based on preclinical studies, a first-in-human clinical study was conducted to evaluate the safety, tolerability, and pharmacokinetics of VDJ001. Methods: This is a single-center, randomized, double-blinded, placebo-controlled phase I dose-escalation study conducted in healthy Chinese volunteers. Four cohorts were designed with dosages ranging from 1 to 8 mg/kg. There were equal numbers of female and male volunteers in each cohort. Enrolled subjects randomly received a single intravenous administration of VDJ001 or placebo (VDJ001: placebo = 4:1 in both female and male volunteers). Three sentinel volunteers in the 1 mg/kg cohort were first administered, and the treatment of the other seven volunteers was carried out after a safety assessment on D15. The following cohort was conducted only when the safety profile was evaluated as acceptable on D29 of the previous cohort. Samples for pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity were collected at specified time points and analyzed through validated methods. Adverse events and the results of the examination and laboratory were analyzed to assess the safety profile. Results: All cohorts were carried out according to the protocol. With the escalation of dosage, Cmax increased linearly, and AUC0-t and AUC0-∞ increased in a non-linear manner, while clearance decreased and t1/2 prolonged. Six volunteers who received VDJ001 tested ADA-positive, among whom one participant tested Nab-positive on D57. One volunteer in the placebo group tested ADA-positive but Nab-negative. CRP concentrations were not found to be correlated with the dosage. Both IL-6 and sIL-6R concentrations increased after the administration of VDJ001. All adverse events were mild to moderate in severity. No serious adverse events were reported in this study. No unexpected or clinically significant safety issues were found. Conclusion: The safety and tolerability of VDJ001 are acceptable with a single intravenous dosage of 1∼8 mg/kg. Further clinical trials are warranted.

Randomized, Double-Blind, Placebo-Controlled, Phase I, Dose- Escalation Study to Evaluate the Tolerance, Pharmacokinetics, Pharmacodynamics and Immunogenicity of PEGylated Urate Oxidase for Injection in Healthy Adults and Hyperuricemia Volunteers: Study Protocol.

Introduction: Hyperuricemia is a disease with abnormal purine metabolism, which leads to the increase of urate concentration. It is an independent risk factor for the occurrence and development of metabolic syndrome, type 2 diabetes, hypertension, cardiovascular disease, chronic kidney disease, and gout. The enzyme urate oxidase can metabolize urate to allantoin, resulting in decreased urate concentrations. Pegylated the urate oxidase can extend half-life and decrease immunogenicity of the protein. This trial aims to evaluate the safety, tolerability, pharmacokinetics(PK), pharmacodynamics(PD) and immunogenicity of a new intravenous PEGylated urate oxidase produced by Xiuzheng Bio-Medicine Research Institute Co., Ltd. Methods and Analysis: A randomized, double-blind, placebo-controlled, phase I, dose escalation study will be conducted in China. In total, 56 subjects will be enrolled in the study, with 24 healthy subjects in the low dose-escalation stage and 32 patients with hyperuricemia in the high dose-escalation stage. There is a bridging between the two stages. Subjects are randomized to PEGylated urate oxidase or the placebo in a 3:1 ratio in each group and followed up for 71 days observation. The primary outcomes include PK, PD, tolerability; the secondary outcomes include safety and immunogenicity. Ethics and Dissemination: The trial is performed abiding by the Declaration of Helsinki, Good clinical practice (GCP) and the guidelines of China National Medical Products Administration (NMPA). Relevant documents, including protocol, informed consent and drug inspection report, are all approved independently by the Medical Ethics Committee of the Affiliated Hospital of Qingdao University. The first subject was enrolled on January 17, 2022. Trial Registration: Clinicaltrials, NCT05226013 (Registered April 2, 2022, Retrospectively registered). ChinaDrugTrials, CTR20211801(Registered July 27, 2021).

Urinary excretion of L-carnitine, acetyl-L-carnitine, propionyl-L-carnitine and their antioxidant activities after single dose administration of L-carnitine in healthy subjects

The urine excretion of L-carnitine (LC), acetyl-L-carnitine (ALC) and propionyl-Lcarnitine (PLC) and their relations with the antioxidant activities are presently unknown. Liquid L-carnitine (2.0 g) was administered orally as a single dose in 12 healthy subjects. Urine concentrations of LC, ALC and PLC were detected by HPLC. Superoxide dismutase (SOD), total antioxidative capacity (T-AOC), malondialdehyde (MDA) and nitrogen monoxidum (NO) activities were measured by spectrophotometric methods. The 0~2 h, 2~4 h, 4~8 h, 8~12 h, 12~24 h excretion of LC was 53.13±31.36 µmol, 166.93±76.87 µmol, 219.92±76.30 µmol, 100.48±23.89 µmol, 72.07±25.77 µmol, respectively. The excretion of ALC was 29.70±14.43 µmol, 80.59±32.70 µmol, 109.85±49.21 µmol, 58.65±18.55 µmol, and 80.43±35.44 µmol, respectively. The urine concentration of PLC was 6.63±4.50 µmol, 15.33±12.59 µmol, 15.46±6.26 µmol, 13.41±11.66 µmol and 9.67±7.92 µmol, respectively. The accumulated excretion rate of LC was 6.1% within 24h after its administration. There was also an increase in urine concentrations of SOD and T-AOC, and a decrease in NO and MDA. A positive correlation was found between urine concentrations of LC and SOD (r = 0.8277) or T-AOC (r = 0.9547), and a negative correlation was found between urine LC excretions and NO (r = -0.8575) or MDA (r = 0.7085). In conclusion, a single oral LC administration let to a gradual increase in urine L-carnitine excretion which was associated with an increase in urine antioxidant enzymes and the total antioxidant capacities. These data may be useful in designing therapeutic regimens of LC or its analogues in the future.

A excreção urinária de L-carnitina (LC), acetil-L-carnitina (ALC) e propionil-L-carnitine (PLC) e as suas relações com as atividades antioxidantes são presentemente desconhecidos. Líquido de L-carnitina (2,0 g) foi administrada por via oral como uma dose única em 12 indivíduos saudáveis. As concentrações urinárias de LC, PLC e ALC foram detectados por HPLC. Atividades superóxido dismutase (SOD), a capacidade antioxidante total (T-AOC), malondialdeído (MDA) e óxido nítrico (NO) foram medidas por métodos espectrofotométricos. O 0~2 h, 2~4 h, 4~8 h, 8~12 h, 12~24 h excreção de LC foi 53,13±31.36 µmol, 166,93±76.87 µmol, 219,92±76.30 µmol, 100,48±23.89 µmol, 72,07±25.77 µmol, respectivamente. A excreηão de ALC foi 29,70±14.43 µmol, 80,59±32.70 µmol, 109,85±49.21 µmol, 58,65±18.55 µmol, e 80,43±35.44 µmol, respectivamente. A concentraηão de urina de PLC foi 6,63±4.50 µmol, 15,33±12.59 µmol, 15,46±6.26 µmol, 13,41±11.66 µmol e 9,67±7.92 µmol, respectivamente. A taxa de excreηão acumulada de LC foi de 6,1% 24 horas após sua administração. Houve também um aumento nas concentrações de urina de SOD e T-COA e diminuição de NO e de MDA. Correlação positiva foi encontrada entre as concentrações de urina de LC e SOD (r = 0,8277) ou T-AOC (r = 0,9547) e correlação negativa entre a excreção de LC e NO (r = -0,8575) ou MDA (r = 0,7085). Em conclusão, a administração oral única de LC leva ao aumento gradual na excreção urinária de L-carnitina, que foi associada com o aumento das enzimas antioxidantes na urina e as capacidades antioxidantes totais. Estes dados podem ser úteis no futuro para o planejamento de esquemas terapêuticos de LC ou os seus análogos, no futuro.