Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 93
Filtrar
1.
Adv Mater ; : e2400523, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594481

RESUMO

The interaction between oxygen species and metal sites of various orbitals exhibits intimate correlation with the oxygen reduction reaction (ORR) kinetics. Herein, a new approach for boosting the inherent ORR activity of atomically dispersed Fe-N-C matrix is represented by implanting Fe atomic clusters nearby. The as-prepared catalyst delivers excellent ORR activity with half-wave potentials of 0.78 and 0.90 V in acidic and alkaline solutions, respectively. The decent ORR activity can also be validated from the high-performance rechargeable Zn-air battery. The experiments and density functional theory calculations reveal that the electron spin-state of monodispersed Fe active sites is transferred from the low spin (LS, t2g 6 eg 0) to the medium spin (MS, t2g 5 eg 1) due to the involvement of Fe atomic clusters, leading to the spin electron filling in σ∗ orbit, by which it favors OH- desorption and in turn boosts the reaction kinetics of the rate-determining step. This work paves a solid way for rational design of high-performance Fe-based single atom catalysts through spin manipulation.

2.
J Chem Inf Model ; 64(9): 3599-3604, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38620066

RESUMO

Understanding tautomerism and characterizing solvent effects on the dynamic processes pose significant challenges. Using enhanced-sampling molecular dynamics based on state-of-the-art deep learning potentials, we investigated the tautomeric equilibria of glycine in water. We observed that the tautomerism between neutral and zwitterionic glycine can occur through both intramolecular and intermolecular proton transfers. The latter proceeds involving a contact anionic-glycine-hydronium ion pair or separate cationic-glycine-hydroxide ion pair. These pathways with comparable barriers contribute almost equally to the reaction flux.


Assuntos
Glicina , Simulação de Dinâmica Molecular , Solventes , Água , Glicina/química , Água/química , Solventes/química , Isomerismo , Prótons , Conformação Molecular
3.
Biomed Pharmacother ; 172: 116266, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38350368

RESUMO

BACKGROUND: ß-Elemene (IUPAC name: (1 S,2 S,4 R)-1-ethenyl-1-methyl-2,4-bis(prop-1-en-2-yl) cyclohexane), is a natural compound found in turmeric root. Studies have demonstrated its diverse biological functions, including its anti-tumor properties, which have been extensively investigated. However, these have not yet been reviewed. The aim of this review was to provide a comprehensive summary of ß-elemene research, with respect to disease treatment. METHODS: ß-Elemene-related articles were found in PubMed, ScienceDirect, and Google Scholar databases to systematically summarize its structure, pharmacokinetics, metabolism, and pharmacological activity. We also searched the Traditional Chinese Medicine System Pharmacology database for therapeutic targets of ß-elemene. We further combined these targets with the relevant literature for KEGG and GO analyses. RESULTS: Studies on the molecular mechanisms underlying ß-elemene activity indicate that it regulates multiple pathways, including STAT3, MAPKs, Cyclin-dependent kinase 1/cyclin B, Notch, PI3K/AKT, reactive oxygen species, METTL3, PTEN, p53, FAK, MMP, TGF-ß/Smad signaling. Through these molecular pathways, ß-elemene has been implicated in tumor cell proliferation, apoptosis, migration, and invasion and improving the immune microenvironment. Additionally, ß-elemene increases chemotherapeutic drug sensitivity and reverses resistance by inhibiting DNA damage repair and regulating pathways including CTR1, pak1, ERK1/2, ABC transporter protein, Prx-1 and ERCC-1. Nonetheless, owing to its lipophilicity and low bioavailability, additional structural modifications could improve the efficacy of this drug. CONCLUSION: ß-Elemene exhibits low toxicity with good safety, inhibiting various tumor types via diverse mechanisms in vivo and in vitro. When combined with chemotherapeutic drugs, it enhances efficacy, reduces toxicity, and improves tumor killing. Thus, ß-elemene has vast potential for research and development.


Assuntos
Neoplasias , Fosfatidilinositol 3-Quinases , Sesquiterpenos , Humanos , Terapia Combinada , Adjuvantes Imunológicos , Adjuvantes Farmacêuticos , Neoplasias/tratamento farmacológico , Compostos Fitoquímicos , Microambiente Tumoral , Metiltransferases
4.
Cancer Sci ; 115(4): 1085-1101, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38287908

RESUMO

Regulator of G protein signaling 1 (RGS1) is closely associated with the tumor immune microenvironment and is highly expressed in various tumors and immune cells. The specific effects of RGS1 in the dynamic progression from chronic gastritis to gastric cancer have not been reported, and the role of tumor-associated macrophages (TAMs) is also unclear. In the present study, RGS1 was identified as an upregulated gene in different pathological stages ranging from chronic gastritis to gastric cancer by using Gene Expression Omnibus (GEO) screening together with pancancer analysis of The Cancer Genome Atlas and clinical prognostic analysis. The results indicated that RGS1 is highly expressed in gastric cancer and has potential prognostic value. We confirmed through in vivo experiments that RGS1 inhibited the proliferation of gastric cancer cells and promoted apoptosis, which was further corroborated by in vitro experiments. Additionally, RGS1 influenced cell migration and invasion. In our subsequent investigation of RGS1, we discovered its role in the immune response. Through analyses of single-cell and GEO database data, we confirmed its involvement in immune cell regulation, specifically TAM activation. Subsequently, we conducted in vivo and in vitro experiments to confirm the involvement of RGS1 in polarizing M1 macrophages while indirectly regulating M2 macrophages through tumor cells. In conclusion, RGS1 could be a potential target for the transformation of chronic gastritis into gastric cancer and has a measurable impact on TAMs, which warrants further in-depth research.


Assuntos
Gastrite , Neoplasias Gástricas , Humanos , Macrófagos Associados a Tumor/metabolismo , Neoplasias Gástricas/patologia , Transdução de Sinais , Proteínas de Ligação ao GTP/metabolismo , Microambiente Tumoral
5.
BMC Cardiovasc Disord ; 24(1): 59, 2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38238685

RESUMO

OBJECTIVE: To investigate the risk factors for thrombocytopenia after transcatheter occlusion operation of patent ductus arteriosus (PDA). METHOD: Retrospective analyses were conducted using clinical data from 106 patients with PDA who underwent transcatheter closure operations at Henan Provincial Chest Hospital, Zhengzhou University, from January 2018 to June 2022. The study compared the changes in platelet counts before and after the operation, and investigated the risk factors for thrombocytopenia following PDA closure in different groups and layers. RESULTS: The platelet count of patients with PDA significantly decreased after undergoing transcatheter PDA occlusion. Logistic regression analysis revealed that factors such as PDA diameter, occluder diameter, pressure difference on the two sides of the occluder, and residual shunt were associated with an increased risk of thrombocytopenia following PDA occlusion. Specifically, the size of the occluder and the pressure difference between the two sides of the occluder were found to have a negative correlation with the postoperative platelet count. Further subgroup analysis demonstrated that the incidence of total thrombocytopenia was significantly higher in the large PDA group compared to the small-medium PDA groups. CONCLUSION: Our findings suggest that occluder diameter, the pressure difference between the two sides of the occluder, and the residual shunt are major risk factors correlated with the incidence of postoperative thrombocytopenia. However, a multicenter and long-term prospective study is required to further evaluate the prognosis of PDA patients with thrombocytopenia after transcatheter occlusion.


Assuntos
Permeabilidade do Canal Arterial , Dispositivo para Oclusão Septal , Trombocitopenia , Humanos , Lactente , Cateterismo Cardíaco/efeitos adversos , Permeabilidade do Canal Arterial/diagnóstico por imagem , Permeabilidade do Canal Arterial/terapia , Contagem de Plaquetas , Estudos Retrospectivos , Fatores de Risco , Trombocitopenia/diagnóstico , Trombocitopenia/epidemiologia , Trombocitopenia/etiologia , Resultado do Tratamento
6.
ACS Nano ; 18(1): 1214-1225, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38150422

RESUMO

By substituting the oxygen evolution reaction (OER) with the anodic urea oxidation reaction (UOR), it not only reduces energy consumption for green hydrogen generation but also allows purification of urea-rich wastewater. Spin engineering of the d orbital and oxygen-containing adsorbates has been recognized as an effective pathway for enhancing the performance of electrocatalysts. In this work, we report the fabrication of a bifunctional electrocatalyst composed of amorphous RuO2-coated NiO ultrathin nanosheets (a-RuO2/NiO) with abundant amorphous/crystalline interfaces for hydrogen evolution reaction (HER) and UOR. Impressively, only 1.372 V of voltage is required to attain a current density of 10 mA cm-2 over a urea electrolyzer. The increased oxygen vacancies in a-RuO2/NiO by incorporation of amorphous RuO2 enhance the total magnetization and entail numerous spin-polarized electrons during the reaction, which speeds up the UOR reaction kinetics. The density functional theory study reveals that the amorphous/crystalline interfaces promote charge-carrier transfer, and the tailored d-band center endows the optimized adsorption of oxygen-generated intermediates. This kind of oxygen vacancy induced spin-polarized electrons toward boosting HER and UOR kinetics and provides a reliable reference for exploration of advanced electrocatalysts.

7.
Pak J Pharm Sci ; 36(6): 1759-1765, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38124416

RESUMO

In recent years, Chinese herbal compounds have gained significant prominence in the treatment of gastric cancer. The goal of this study was to investigate the antitumor effect of HuangJinShuangShen granules (HJSS) combined with 5-fluorouracil on MFC gastric cancer mice. In this study, the MFC model with gastric cancer was successfully established. After continuous administration for 14 d, the body weight, tumor volume and weight and spleen mass of mice in each group were recorded. The levels of IFN-γ and TGF-ß1 in serum were detected by ELISA. The expression of apoptosis proteins in tumor tissues was detected by Western blotting. Compared with the model group and the 5-FU group, the combined drug group can significantly inhibit tumor growth, reduce tumor volume, promote tumor cell necrosis and increase spleen index in mice. At the same time, the combined treatment group significantly increased IFN-γ level and BAX protein expression, decreased TGF-ß1 level and decreased Bcl2, Caspase-9 and Cleaved Caspase-3 protein expressions. These findings provide evidence that HJSS can augment the suppressive impact of 5-FU on tumor growth in gastric cancer mice, potentially through the induction of tumor cell apoptosis and the restoration of immune function.


Assuntos
Fluoruracila , Neoplasias Gástricas , Animais , Camundongos , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Neoplasias Gástricas/metabolismo , Linhagem Celular Tumoral , Apoptose , Fator de Crescimento Transformador beta
8.
Nanoscale ; 15(48): 19604-19616, 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38018426

RESUMO

Developing low-cost, high-efficiency and stable electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is crucial but highly challenging. Density functional theory (DFT) calculations reveal that doping ruthenium (Ru) into catalysts can effectively optimize their electronic structure, hence leading to an optimal Gibbs free energy on the catalyst surface. Herein, an ultra-low Ru (about 2.34 wt%)-doped Ni3Se2 nanowire catalyst (i.e., Ru/Ni3Se2) supported on nickel foam has been fabricated by a hydrothermal reaction followed by a chemical etching process. The unique three-dimensional (3D) interconnected nanowires not only endow Ru and Ni3Se2 with uniform distribution and coupling, but also provide higher electrical conductivity, more active sites, an optimized electronic structure and favorable reaction kinetics. Therefore, the as-obtained Ru/Ni3Se2 catalyst exhibits excellent electrocatalytic performance, with low overpotentials of 24 and 211 mV to supply a current density value of 10 mA cm-2 towards the HER and OER in an alkaline environment, respectively. Notably, the as-fabricated Ru/Ni3Se2 catalyst only requires a low voltage of 1.476 V to derive a current density of 10 mA cm-2 in the constructed two-electrode alkaline electrolyzer and exhibits exceptionally high stability. This work will provide a novel strategy for the design and fabrication of low-cost and high-performance bifunctional electrocatalysts for hydrogen production by water electrolysis.

9.
Ecotoxicol Environ Saf ; 266: 115553, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37839188

RESUMO

The OH radical recycling mechanism in isoprene oxidation is one of the most exciting topics in atmospheric chemistry, and the corresponding studies expand our understanding of oxidation mechanisms of volatile organic compounds in the troposphere and provide reliable evidence to improve and develop conventional atmospheric models. In this work, we performed a detailed theoretical kinetics study on the Z-δ-(4-OH, 1-OO)-ISOPOO radical chemistry, which is proposed as the heart of OH recycling in isoprene oxidation. With the full consideration of its accumulation and consumption channels, we studied and discussed the fate of Z-δ-(4-OH, 1-OO)-ISOPOO radical by solving the energy-resolved master equation over a broad range of conditions, including not only room temperatures but also high temperatures of a forest fire or low temperatures and pressures of the upper troposphere. We found non-negligible pressure dependence of its fate at combustion temperatures (up to two orders of magnitude) and demonstrated the significance of both the multi-structural torsional anharmonicity and tunneling for accurately calculating kinetics of the studied system. More interestingly, the tunneling effect on the phenomenological rate constants of the H-shift reaction channel is also found to be pressure-dependent due to the competition with the O2 loss reaction. In addition, our time evolution calculations revealed a two-stage behavior of critical species in this reaction system and estimated the shortest half-lives for the Z-δ-(4-OH, 1-OO)-ISOPOO radical at various temperatures, pressures and altitudes. This detailed kinetics study of Z-δ-(4-OH, 1-OO)-ISOPOO radical chemistry offers a typical example to deeply understand the core mechanism of OH recycling pathways in isoprene oxidation, and provides valuable insights for promoting the development of relevant atmospheric models.


Assuntos
Radical Hidroxila , Modelos Teóricos , Radical Hidroxila/química , Temperatura , Butadienos , Cinética
10.
J Chem Theory Comput ; 19(19): 6577-6588, 2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37772732

RESUMO

Trajectory surface hopping (TSH) is a widely used mixed quantum-classical dynamics method that is used to simulate molecular dynamics with multiple electronic states. In TSH, time-derivative coupling is employed to propagate the electronic coefficients and in that way to determine when the electronic state on which the nuclear trajectory is propagated switches. In this work, we discuss nonadiabatic TSH dynamics algorithms employing the curvature-driven approximation and overlap-based time derivative couplings, and we report test calculations on six photochemical reactions where we compare the results to one another and to calculations employing analytic nonadiabatic coupling vectors. We correct previous published results thanks to a bug found in the software. We also provide additional, more detailed studies of the time-derivative couplings. Our results show good agreement between curvature-driven algorithms and overlap-based algorithms.

11.
Clin Exp Hypertens ; 45(1): 2229538, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37395230

RESUMO

OBJECTIVE: Neointimal hyperplasia is the primary mechanism underlying atherosclerosis and restenosis after percutaneous coronary intervention. Ketogenic diet (KD) exerts beneficial effects in various diseases, but whether it could serve as non-drug therapy for neointimal hyperplasia remains unknown. This study aimed to investigate the effect of KD on neointimal hyperplasia and the potential mechanisms. METHODS AND RESULTS: Carotid artery balloon-injury model was employed in adult Sprague-Dawley rats to induce neointimal hyperplasia. Then, animals were subjected to either standard rodent chow or KD. For in-vitro experiment, impacts of ß-hydroxybutyrate (ß-HB), the main mediator of KD effects, on platelet-derived growth factor BB (PDGF-BB) induced vascular smooth muscle cell (VSMC) migration and proliferation were determined. Balloon injury induced event intimal hyperplasia and upregulation of protein expression of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA), and these changes were significantly ameliorated by KD. In addition, ß-HB could markedly inhibit PDGF-BB induced VMSC migration and proliferation, as well as inhibiting expressions of PCNA and α-SMC. Furthermore, KD inhibited balloon-injury induced oxidative stress in carotid artery, indicated by reduced ROS level, malondialdehyde (MDA) and myeloperoxidase (MPO) activities, and increased superoxide dismutase (SOD) activity. We also found balloon-injury induced inflammation in carotid artery was suppressed by KD, indicated by decreased expressions of proinflammatory cytokines IL-1ß and TNF-α, and increased expression of anti-inflammatory cytokine IL-10. CONCLUSION: KD attenuates neointimal hyperplasia through suppressing oxidative stress and inflammation to inhibit VSMC proliferation and migration. KD may represent a promising non-drug therapy for neointimal hyperplasia associated diseases.


Assuntos
Lesões das Artérias Carótidas , Dieta Cetogênica , Ratos , Animais , Hiperplasia/complicações , Ratos Sprague-Dawley , Becaplermina/metabolismo , Becaplermina/farmacologia , Becaplermina/uso terapêutico , Antígeno Nuclear de Célula em Proliferação/metabolismo , Antígeno Nuclear de Célula em Proliferação/farmacologia , Antígeno Nuclear de Célula em Proliferação/uso terapêutico , Neointima/complicações , Neointima/tratamento farmacológico , Neointima/metabolismo , Lesões das Artérias Carótidas/complicações , Lesões das Artérias Carótidas/tratamento farmacológico , Lesões das Artérias Carótidas/metabolismo , Estresse Oxidativo , Inflamação/complicações , Proliferação de Células , Movimento Celular , Células Cultivadas
12.
Entropy (Basel) ; 25(7)2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37509909

RESUMO

In this study, the influence of an axial-electromagnetic field treatment device (AEFTD) with a solenoid structure using different electromagnetic frequencies on calcium carbonate (CaCO3) crystallization fouling on the tube side of a shell-and-tube heat exchanger was investigated. The experimental results indicated that the application of the AEFTD could effectively reduce fouling resistance and decelerate the growth rate of CaCO3 fouling. The opposite trend between fouling resistance and the outlet temperature of an experimental fluid indicated that the application of the AEFTD could enhance heat transfer. Meanwhile, the crystal morphologies of the fouling samples were analyzed by means of scanning electron microscopy (SEM). The axial-electromagnetic field favored the formation of vaterite as opposed to calcite. Non-adhesive vaterite did not easily aggregate into clusters and was suspended in bulk to form muddy fouling that could be carried away by turbulent flow. Furthermore, the anti-fouling mechanism of the axial-electromagnetic field is discussed in detail. The anti-fouling effect of the AEFTD on CaCO3 fouling exhibited extreme characteristics in this study. Therefore, the effectiveness of the AEFTD is contingent upon the selection of the electromagnetic parameters.

13.
Biomimetics (Basel) ; 8(3)2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37504171

RESUMO

Fiber-reinforced composites are an ideal high-performance composite material made from a combination of high-strength continuous fibers and a polymer matrix. Compared to short cut fibers, continuous long strand fibers can improve the mechanical properties of fiber composites more effectively. Herein, continuous aramid fiber-reinforced PLA filaments with fiber centering were prepared by modifying the outlet design of a desktop-grade thermoplastic single-screw melt extruder. Inspired by the cross-laminated structure of a beetle's mandible fibers, a biomimetic structure composite was printed, which demonstrates a significant influence on the mechanical properties. The G-code printing program was developed, and the microstructure of the fracture surface of the specimen was analyzed. The uniform and orderly arrangement of aramid fibers within the PLA resin-based 3D-printed specimen was found. Consequentially, the bionic composites exhibits a 12% increase in tensile strength and a 5% increase in impact toughness, confirming the feasibility of utilizing continuous 3D printing to manufacture long bundles of aramid fiber composite filaments for enhanced mechanical performances.

14.
ACS Nano ; 17(11): 10906-10917, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37260372

RESUMO

Metal-organic frameworks (MOFs) show great promise for electrocatalysis owing to their tunable ligand structures. However, the poor stability of MOFs impedes their practical applications. Unlike the general pathway for engineering ligands, we report herein an innovative strategy for leveraging metal nodes to improve both the catalytic activity and the stability. Our electrolysis cell with a NiRh-MOF||NiRh-MOF configuration exhibited 10 mA cm-2 at an ultralow cell voltage of 0.06 V in alkaline seawater (with 0.3 M N2H4), outperforming its counterpart benchmark Pt/C||Pt/C cell (0.12 V). Impressively, the incorporation of Rh into a MOF secured a robust stability of over 60 h even when working in the seawater electrolyte. Experimental results and theoretical calculations revealed that Rh atoms serve as the active sites for hydrogen evolution while Ni nodes are responsible for the hydrazine oxidation during the hydrazine oxidation assisted seawater splitting. This work provides a paradigm for green hydrogen generation from seawater.

15.
J Chem Theory Comput ; 19(11): 3284-3302, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37164004

RESUMO

Intramolecular hydrogen shift reactions in peroxy radicals (RO2• → •QOOH) play key roles in the low-temperature combustion and in the atmospheric chemistry. In the present study, we found that a mild-to-moderate multireference character of a potential energy surface (PES) is widely present in four typical hydrogen shift reactions of peroxy radicals (RO2•, R = ethyl, vinyl, formyl methyl, and acetyl) by a systematic assessment based on the T1 diagnostic, %TAE diagnostic, M diagnostic, and contribution of the dominant configuration of the reference CASSCF wavefunction (C02). To assess the effects of these inherent multireference characters on electronic structure calculations, we compared the PESs of the four reactions calculated by the multireference method CASPT2 in the complete basis set (CBS) limit, single-reference method CCSD(T)-F12, and single-reference-based composite method WMS. The results showed that ignoring the multireference character will introduce a mean unsigned deviation (MUD) of 0.46-1.72 kcal/mol from CASPT2/CBS results by using the CCSD(T)-F12 method or a MUD of 0.49-1.37 kcal/mol by WMS for three RO2• reactions (R = vinyl, formyl methyl, and acetyl) with a stronger multireference character. Further tests by single-reference Kohn-Sham (KS) density functional theory methods showed even larger deviations. Therefore, we specifically developed a new hybrid meta-generalized gradient approximation (GGA) functional M06-HS for the four typical H-shift reactions of peroxy radicals based on the WMS results for the ethyl peroxy radical reaction and on the CASPT2/CBS results for the others. The M06-HS method has an averaged MUD of 0.34 kcal/mol over five tested basis sets against the benchmark PESs, performing best in the tested 38 KS functionals. Last, in a temperature range of 200-3000 K, with the new functional, we calculated the high-pressure-limit rate coefficients of these H-shift reactions by the multi-structural variational transition-state theory with the small-curvature tunneling approximation (MS-CVT/SCT) and the thermochemical properties of all of the involved key radicals by the multi-structural torsional (MS-T) anharmonicity approximation method.

16.
Inorg Chem ; 62(19): 7424-7433, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37141089

RESUMO

For large-scale industrial applications, it is highly desirable to create effective, economical electrocatalysts with long-term stability for the hydrogen evolution reaction (HER) at a large current density. Herein, we report a unique motif with crystalline CoFe-layered hydroxide (CoFe-LDH) nanosheets enclosed by amorphous ruthenium hydroxide (a-Ru(OH)3/CoFe-LDH) to realize the efficient hydrogen production at 1000 mA cm-2, with a low overpotential of 178 mV in alkaline media. During the continuous HER process for 40 h at such a large current density, the potential remains almost constant with only slight fluctuations, indicating good long-term stability. The remarkable HER performance can be attributed to the charge redistribution caused by abundant oxygen vacancies in a-Ru(OH)3/CoFe-LDH. The increased electron density of states lowers the charge-transfer resistance and promotes the formation and release of H2 molecules. The water-splitting electrolyzer with a-Ru(OH)3/CoFe-LDH as both an anode and a cathode in 1.0 M KOH demonstrates stable hydrogen production and a 100% faradic efficiency. The design strategy of interface engineering in this work will inspire the design of practical electrocatalysts for water splitting on an industrial scale.

18.
J Chem Theory Comput ; 19(6): 1672-1685, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36877830

RESUMO

Mixed quantum-classical nonadiabatic dynamics is a widely used approach to simulate molecular dynamics involving multiple electronic states. There are two main categories of mixed quantum-classical nonadiabatic dynamics algorithms, namely, trajectory surface hopping (TSH) in which the trajectory propagates on a single potential energy surface, interrupted by hops, and self-consistent-potential (SCP) methods, such as semiclassical Ehrenfest, in which propagation occurs on a mean-field surface without hops. In this work, we will illustrate an example of severe population leaking in TSH. We emphasize that such leaking is a combined effect of frustrated hops and long-time simulations that drive the final excited-state population toward zero as a function of time. We further show that such leaking can be alleviated-but not eliminated-by the fewest switches with time uncertainty TSH algorithm (here implemented in the SHARC program); the time uncertainty algorithm slows down the leaking process by a factor of 4.1. The population leaking is not present in coherent switching with decay of mixing (CSDM), which is an SCP method with non-Markovian decoherence included. Another result in this paper is that we find very similar results with the original CSDM algorithm, with time-derivative CSDM (tCSDM), and with curvature-driven CSDM (κCSDM). Not only do we find good agreement for electronically nonadiabatic transition probabilities but also we find good agreement of the norms of the effective nonadiabatic couplings (NACs) that are derived from the curvature-driven time-derivative couplings as implemented in κCSDM with the time-dependent norms of the nonadiabatic coupling vectors computed by state-averaged complete-active-space self-consistent field theory.

19.
Exp Ther Med ; 25(3): 139, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36845955

RESUMO

Lung cancer is one of the commonest malignant tumors in the world today, causing millions of mortalities every year. New methods to treat lung cancer are urgently needed. Salviae miltiorrhiza Bunge is a common Chinese medicine, often used for promoting blood circulation. In the past 20 years, Salviae miltiorrhiza has made significant progress in the treatment of lung cancer and is considered to be one of the most promising methods to fight against the disease. A great amount of research has shown that the mechanism of Salviae miltiorrhiza against human lung cancer mainly includes inhibiting the proliferation of lung cancer cells, promoting lung cancer cell apoptosis, inducing cell autophagy, regulating immunity and resisting angiogenesis. Research has shown that Salviae miltiorrhiza has certain effects on the resistance to chemotherapy drugs. The present review discussed the status and prospects of Salviae miltiorrhiza against human lung cancer.

20.
J Chem Theory Comput ; 18(12): 7671-7682, 2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36441527

RESUMO

Identification of internal-rotation modes in the normal-mode analysis of complex molecules is important for accurately describing the thermodynamic properties and kinetics of complex molecules when it is necessary to treat the anharmonicity of torsions and the multiconformer anharmonicity caused by the internal rotations. However, identifying and distinguishing torsional modes are very challenging because they are coupled to one another. In this work, we present a new strategy to automatically identify torsional vibrations and separate them from the other vibrational modes. By combining a redundant-internal-coordinate auto-generation procedure with torsional projection techniques, we automate the procedure of identifying and separating the coupled torsions, and we show that we can obtain robust and consistent results with various reasonable definitions of redundant-internal-coordinate sets. This model has been implemented in a new development version of the MSTor program to reduce the user input needed for multistructural and torsional anharmonicity (MS-T) calculations. The new method is called multistructural and torsional anharmonicity with a coupled torsional potential and delocalized torsions ([MS-T(CD)]. As example applications, we consider MS-T(CD) calculations on three molecules (2-hexyl radical, n-propylbenzene, and 5-hydroperoxy-6-oxohexanoylperoxy radical) that have multiple rotors and that provide challenges to choosing good sets of nonredundant-internal coordinates, and we compare the performance of the new strategy to five other torsion identification methods. The new strategy is demonstrated to be efficient in separating the torsional and nontorsional elements in the Hessian matrix, as well as in providing reasonable projected nontorsional frequencies to be used for calculations of partition function and thermochemistry.


Assuntos
Teoria Quântica , Vibração , Termodinâmica , Cinética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA