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2.
Nanomaterials (Basel) ; 14(10)2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38786823

RESUMO

Electro-optic modulators (EOMs) are pivotal in bridging electrical and optical domains, essential for diverse applications including optical communication, microwave signal processing, sensing, and quantum technologies. However, achieving the trifecta of high-density integration, cost-effectiveness, and superior performance remains challenging within established integrated photonics platforms. Enter thin-film lithium niobate (LN), a recent standout with its inherent electro-optic (EO) efficiency, proven industrial performance, durability, and rapid fabrication advancements. This platform inherits material advantages from traditional bulk LN devices while offering a reduced footprint, wider bandwidths, and lower power requirements. Despite its recent introduction, commercial thin-film LN wafers already rival or surpass established alternatives like silicon and indium phosphide, benefitting from decades of research. In this review, we delve into the foundational principles and technical innovations driving state-of-the-art LN modulator demonstrations, exploring various methodologies, their strengths, and challenges. Furthermore, we outline pathways for further enhancing LN modulators and anticipate exciting prospects for larger-scale LN EO circuits beyond singular components. By elucidating the current landscape and future directions, we highlight the transformative potential of thin-film LN technology in advancing electro-optic modulation and integrated photonics.

3.
Sensors (Basel) ; 24(7)2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38610416

RESUMO

This article presents an analysis of current state-of-the-art sensors and how these sensors work with several mapping algorithms for UAV (Unmanned Aerial Vehicle) applications, focusing on low-altitude and high-speed scenarios. A new experimental construct is created using highly realistic environments made possible by integrating the AirSim simulator with Google 3D maps models using the Cesium Tiles plugin. Experiments are conducted in this high-realism simulated environment to evaluate the performance of three distinct mapping algorithms: (1) Direct Sparse Odometry (DSO), (2) Stereo DSO (SDSO), and (3) DSO Lite (DSOL). Experimental results evaluate algorithms based on their measured geometric accuracy and computational speed. The results provide valuable insights into the strengths and limitations of each algorithm. Findings quantify compromises in UAV algorithm selection, allowing researchers to find the mapping solution best suited to their application, which often requires a compromise between computational performance and the density and accuracy of geometric map estimates. Results indicate that for UAVs with restrictive computing resources, DSOL is the best option. For systems with payload capacity and modest compute resources, SDSO is the best option. If only one camera is available, DSO is the option to choose for applications that require dense mapping results.

4.
Materials (Basel) ; 17(8)2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38673146

RESUMO

The development of a new generation of solid particle solar receivers (SPSRs) with high solar absorptivity (0.28-2.5 µm) and high infrared emissivity (1-22 µm) is crucial and has attracted much attention for the attainment of the goals of "peak carbon" and "carbon neutrality". To achieve the modulation of infrared emission and solar absorptivity, two types of medium- and high-entropy rare-earth hexaboride (ME/HEREB6) ceramics, (La0.25Sm0.25Ce0.25Eu0.25)B6 (MEREB6) and (La0.2Sm0.2Ce0.2Eu0.2Ba0.2)B6 (HEREB6), with severe lattice distortions were synthesized using a high-temperature solid-phase method. Compared to single-phase lanthanum hexaboride (LaB6), HEREB6 ceramics show an increase in solar absorptivity from 54.06% to 87.75% in the range of 0.28-2.5 µm and an increase in infrared emissivity from 76.19% to 89.96% in the 1-22 µm wavelength range. On the one hand, decreasing the free electron concentration and the plasma frequency reduces the reflection and ultimately increases the solar absorptivity. On the other hand, the lattice distortion induces changes in the B-B bond length, leading to significant changes in the Raman scattering spectrum, which affects the damping constant and ultimately increases the infrared emissivity. In conclusion, the multicomponent design can effectively improve the solar energy absorption and heat transfer capacity of ME/HEREB6, thus providing a new avenue for the development of solid particles.

5.
Opt Lett ; 49(6): 1413-1416, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38489413

RESUMO

Tunable optical filters at the chip scale play a crucial role in fulfilling the need for reconfigurability in channel routing, optical switching, and wavelength division multiplexing systems. In this Letter, we propose a tunable double notch filter on thin-film lithium niobate using dual microring architecture. This unique integrated filter is essential for complex photonic integrated circuits, along with multiple channels and various frequency spacing. With only one loaded voltage, the device demonstrates a wide frequency spacing tunability from 16.1 to 89.9 GHz by reversely tuning the resonances of the two microrings while the center wavelength between the two resonances remains unaltered. Moreover, by utilizing the pronounced electro-optic properties of lithium niobate associated with the tight light confined nanophotonic waveguides, the device demonstrates a spacing tunability of 0.82 GHz/V and a contrast of 10-16 dB. In addition, the device has an ultracompact footprint of 0.0248 mm2.

6.
Eur J Pharmacol ; 969: 176425, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38387717

RESUMO

Acute kidney injury (AKI) is a critical condition often associated with systemic inflammation and dysregulated gut microbiota. This study aimed to investigate the effects of the C5a receptor antagonist W54011 on lipopolysaccharide (LPS)-induced AKI, focusing on the colon's C5a/C5a receptor pathway, intestinal barrier integrity, and gut microbiota. Our findings demonstrate that W54011 effectively ameliorated kidney injury in the LPS-induced AKI model by selectively inhibiting the colon's C5a/C5a receptor signalling pathway. Additionally, C5a receptor blockade resulted in the inhibition of colonic inflammation and the reconstruction of the intestinal mucosal barrier. Furthermore, W54011 administration significantly impacted the composition and stability of the gut microbiota, restoring the abundance of dominant bacteria to levels observed in the normal state of the intestinal flora and reducing the abundance of potentially harmful bacterial groups. In conclusion, W54011 alleviates LPS-induced AKI by modulating the interplay between the colon, gut microbiota, and kidneys. It preserves the integrity of the intestinal barrier and reinstates gut microbiota, thereby mitigating AKI symptoms. These findings suggest that targeting the colon and gut microbiota could be a promising therapeutic strategy for AKI treatment.


Assuntos
Injúria Renal Aguda , Compostos de Anilina , Microbioma Gastrointestinal , Tetra-Hidronaftalenos , Humanos , Lipopolissacarídeos , Receptor da Anafilatoxina C5a , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/prevenção & controle , Rim , Inflamação , Colo
7.
Molecules ; 29(4)2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38398631

RESUMO

Aqueous zinc ion batteries (AZIBs) have emerged as a promising battery technology due to their excellent safety, high capacity, low cost, and eco-friendliness. However, the cycle life of AZIBs is limited by severe side reactions and zinc dendrite growth on the zinc electrode surface, hindering large-scale application. Here, an electrolyte optimization strategy utilizing the simplest dipeptide glycylglycine (Gly-Gly) additive is first proposed. Theoretical calculations and spectral analysis revealed that, due to the strong interaction between the amino group and Zn atoms, Gly-Gly preferentially adsorbs on zinc's surface, constructing a stable and adaptive interfacial layer that inhibits zinc side reactions and dendrite growth. Furthermore, Gly-Gly can regulate zinc ion solvation, leading to a deposition mode shift from dendritic to lamellar and limiting two-dimensional dendrite diffusion. The symmetric cell with the addition of a 20 g/L Gly-Gly additive exhibits a cycle life of up to 1100 h. Under a high current density of 10 mA cm-2, a cycle life of 750 cycles further demonstrates the reliable adaptability of the interfacial layer. This work highlights the potential of Gly-Gly as a promising solution for improving the performance of AZIBs.

9.
Medicine (Baltimore) ; 103(1): e36304, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38181297

RESUMO

BACKGROUND: This study aimed to observe clinical efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) gel, medical collagen sponge and rhGM-CSF gel in combination with medical collagen sponge on deep second-degree burns of head, face or neck in infants. METHODS: A total of 108 infants with deep second-degree burns on head, face or neck were randomly divided into rhGM-CSF group, medical collagen sponge group, and rhGM-CSF + medical collagen sponge group. The scab dissolving time, healing time, bacterial positive rate and Vancouver scar scale were evaluated and analyzed. RESULTS: The data analysis showed that scab dissolving time and healing time were shorter in rhGM-CSF + medical collagen sponge group than that in rhGM-CSF group and medical collagen sponge group, and the difference was statistically significant (P < .05). Bacterial positive rate was lower in rhGM-CSF + medical collagen sponge group than that in rhGM-CSF group and medical collagen sponge group (P < .05). After 3 months, score of Vancouver scar scale (scar thickness, pliability, pigmentation and vascularity) was less in rhGM-CSF + medical collagen sponge group than that in rhGM-CSF group and medical collagen sponge group (P < .05). CONCLUSION: rhGM-CSF gel in combination with medical collagen sponge is significantly effective in treating deep second-degree burns of head, face or neck in infants. This combination is beneficial for infection control, acceleration of scab dissolving and wound healing, and reduction of scar hyperplasia and pigmentation, which is worthy of clinical application and promotion.


Assuntos
Queimaduras , Cicatriz , Lactente , Humanos , Colágeno/uso terapêutico , Resultado do Tratamento , Queimaduras/tratamento farmacológico
10.
Acta Biomater ; 176: 51-76, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38237711

RESUMO

Despite the current promise of immunotherapy, many cancer patients still suffer from challenges such as poor immune response rates, resulting in unsatisfactory clinical efficacy of existing therapies. There is an urgent need to combine emerging biomedical discoveries and innovations in traditional therapies. Modulation of the cGAS-STING signalling pathway represents an important innate immunotherapy pathway that serves as a crucial DNA sensing mechanism in innate immunity and viral defense. It has attracted increasing attention as an emerging target for cancer therapy. The recent advancements in nanotechnology have led to the significant utilization of nanomaterials in cancer immunotherapy, owing to their exceptional physicochemical properties such as large specific surface area and efficient permeability. Given the rapid development of cancer immunotherapy driven by the cGAS-STING activation, this study reviews the latest research progress in employing nanomaterials to modulate this signaling pathway. Based on the introduction of the main activation mechanisms of cGAS-STING pathway, this review focuses on nanomaterials that mediate the agonists involved and effectively activate this signaling pathway. In addition, combination nanotherapeutics based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as other immunomodulation in tumor targeting therapy. STATEMENT OF SIGNIFICANCE: Given the rapid development of cancer immunotherapy driven by the cGAS / STING activation, this study reviews the latest research advances in the use of nanomaterials to modulate this signaling pathway. Based on the introduction of key cGAS-STING components and their activation mechanisms, this review focuses on nanomaterials that can mediate the corresponding agonists and effectively activate this signaling pathway. In addition, combination nanotherapies based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as immunomodulation in cancer therapy,.


Assuntos
Nanoestruturas , Neoplasias , Humanos , Imunoterapia , Imunomodulação , Imunidade Inata , Nucleotidiltransferases , Transdução de Sinais , Neoplasias/terapia
11.
Nanomaterials (Basel) ; 14(2)2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38251165

RESUMO

Perovskite/silicon tandem solar cells have garnered considerable interest due to their potential to surpass the Shockley-Queisser limit of single-junction Si solar cells. The rapidly advanced efficiencies of perovskite/silicon tandem solar cells benefit from the significant improvements in perovskite technology. Beginning with the evolution of wide bandgap perovskite cells towards two-terminal (2T) perovskite/silicon tandem solar cells, this work concentrates on component engineering, additives, and interface modification of wide bandgap perovskite cells. Furthermore, the advancements in 2T perovskite/silicon tandem solar cells are presented, and the influence of the central interconnect layer and the Si cell on the progression of the tandem solar cells is emphasized. Finally, we discuss the challenges and obstacles associated with 2T perovskite/silicon tandem solar cells, conducting a thorough analysis and providing a prospect for their future.

12.
Micromachines (Basel) ; 15(1)2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38276855

RESUMO

This work presents highly responsive gate-controlled p-GaN/AlGaN/GaN ultraviolet photodetectors (UVPDs) on Si substrates with a high-transmittance ITO gate. The two-dimensional electron gas (2DEG) in the quantum well of the polarized AlGaN/GaN heterojunction was efficiently depleted by the p-GaN gate, leading to a high photo-to-dark current ratio (PDCR) of 3.2 × 105. The quantum wells of the p-GaN/AlGaN and AlGaN/GaN heterojunctions can trap the holes and electrons excited by the UV illumination, thus efficiently triggering a photovoltaic effect and photoconductive effect, separately. Furthermore, the prepared photodetectors allow flexible adjustment of the static bias point, making it adaptable to different environments. Compared to traditional thin-film semi-transparent Ni/Au gates, indium tin oxide (ITO) exhibits higher transmittance. Under 355 nm illumination, the photodetector exhibited a super-high responsivity exceeding 3.5 × 104 A/W, and it could even exceed 106 A/W under 300 nm illumination. The well-designed UVPD combines both the advantages of the high-transmittance ITO gate and the structure of the commercialized p-GaN/AlGaN/GaN high-electron-mobility transistors (HEMTs), which opens a new possibility of fabricating large-scale, low-cost, and high-performance UVPDs in the future.

13.
J Colloid Interface Sci ; 658: 934-942, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38157617

RESUMO

Electrocatalytic nitrate reduction (NO3RR) technique has emerged as a hotspot in NH3 production, for its practicability, and a series of advanced electrocatalysts with high activity and robust stability needed to be constructed in today's era. In this work, size-tunable Cu nanoparticles on porous nitrogen-doped hexagonal carbon nanorods (Cu@NHC) were reasonably designed and served for catalyzing NO3RR in neutral media. Especially, Cu30%@NHC demonstrated a remarkable electroactivity for NH3 production as it showed a suitable grain size with massive catalytic centers and favorable d band structure with faster *NO3--to-*NO2- catalytic dynamics. As expected, Cu30%@NHC (3628.28 µg h-1 mgcat.-1) had a much higher NH3 yield than those for Cu20%@NHC (1268.42 µg h-1 mgcat.-1) and Cu40%@NHC (725.03 µg h-1 mgcat.-1). And those collected NH3 products indeed derived from NO3RR process revealed by 15N isotope-labeling and systemic control tests. Moreover, Cu30%@NHC was also durable for NO3RR bulk electrolysis with minor loss in activity. This work offered an effective modifying tactics to boost NO3RR catalysis and could guide the design of other advanced electrocatalysts via size-induced surface engineering.

14.
Open Med (Wars) ; 18(1): 20230857, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38075033

RESUMO

Elevated serum uric acid (UA) level is related to type 2 diabetic retinopathy (DR). Vascular endothelial growth factor (VEGF), high-sensitivity C-reactive protein (hs-CRP), and cystatin C (Cys-C) have involvement in type 2 DR complicated with hyperuricemia (HUA) (HUDR), and we explored their clinical values in HUDR. Type 2 DR patients were allocated into HUDR/DR groups, with type 2 diabetes mellitus (T2DM) patients as the control group. Serum VEGF and inflammation markers hs-CRP, and Cys-C levels were assessed by ELISA and immunoturbidimetry. The correlations between serum UA level and VEGF/hs-CRP/Cys-C were analyzed by Pearson tests, diagnostic values of VEGF/hs-CRP/Cys-C were analyzed by receiver operating characteristic curves, and the independent risk factors in HUDR were analyzed by logistic multivariate regression. Serum VEGF/hs-CRP/Cys-C level differences among the T2DM/DR/HUDR groups were statistically significant, with the levels in HUDR > DR > T2DM. Serum UA level in HUDR patients was positively correlated with serum VEGF/hs-CRP/Cys-C. Serum VEGF/hs-CRP/Cys-C assisted in HUDR diagnosis, with their combination showing the greatest diagnostic value. UA/FPG/HbA1C/VEGF/hs-CRP/Cys-C were independent risk factors for HUDR. The incidence of proliferative DR was increased in HUDR patients. Collectively, serum VEGF, hs-CRP, and Cys-C levels in HUDR patients were increased, and HUA might promote DR progression.

15.
Nat Commun ; 14(1): 6550, 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37848430

RESUMO

In this work, via engineering the conformation of cobalt active center in cobalt phthalocyanine molecular catalyst, the catalytic efficiency of electrochemical carbon monoxide reduction to methanol can be dramatically tuned. Based on a collection of experimental investigations and density functional theory calculations, it reveals that the electron rearrangement of the Co 3d orbitals of cobalt phthalocyanine from the low-spin state (S = 1/2) to the high-spin state (S = 3/2), induced by molecular conformation change, is responsible for the greatly enhanced CO reduction reaction performance. Operando attenuated total reflectance surface-enhanced infrared absorption spectroscopy measurements disclose accelerated hydrogenation of CORR intermediates, and kinetic isotope effect validates expedited proton-feeding rate over cobalt phthalocyanine with high-spin state. Further natural population analysis and density functional theory calculations demonstrate that the high spin Co2+ can enhance the electron backdonation via the dxz/dyz-2π* bond and weaken the C-O bonding in *CO, promoting hydrogenation of CORR intermediates.

16.
Phys Chem Chem Phys ; 25(43): 29437-29443, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37846752

RESUMO

The extremely difficult ambipolar doping activation greatly hinders the outstanding performance of diamond for electronic devices. The main concern has been devoted to surface conduction by two-dimensional (2D) carriers. 2D hole gas (2DHG) in the diamond is induced by surface transfer doping dominated by the adsorbate's status and faces stability issues. Meanwhile, a feasible way to generate the other essential ambipolar carrier-2D electron gas (2DEG) is still lacking. We propose that the well-lattice-matched diamond/cBN(111) interfaces can spontaneously induce 2D ambipolar carriers with a giant density of 4.17 × 1014 cm-2, an order higher than other competitors. 2DEG and 2DHG can be separately achieved near the hetero-interfaces consisting of C-N and C-B bonds, respectively. Interestingly, the robust 2D charges are derived from a novel bulk-induced polarization-discontinuity at the interfaces, which can be attributed to an unexpected non-zero formal polarization of centrosymmetric cBN along the [111] direction. The existence of 2D ambipolar carriers at the diamond/cBN(111) interfaces has resolved the missing n-type conduction in diamond, thus opening up possibilities for complementary logic applications. Additionally, the high density of quantum-confined 2D ambipolar carriers provides an excellent platform for strongly correlated systems, which could lead to novel quantum information processing applications.

17.
J Phys Chem B ; 127(43): 9390-9398, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37851407

RESUMO

Metal-organic frameworks (MOFs) with ultrahigh specific surface area and porosity have emerged as promising nanoporous materials for gas separation, storage, and adsorption-driven thermal energy conversion systems such as adsorption heat pumps. However, an inadequate understanding of the thermal transport of MOFs with adsorbed gases hampers the thermal management of such systems in practical applications. In this work, an in-depth investigation on the mechanistic heat transfer performance of three topological zeolitic imidazolate frameworks (ZIFs) upon hydrogen, methane, and ethanol adsorption was carried out by molecular dynamics simulations. It is revealed that the trade-off between the additional heat transfer pathway and phonon scattering resulting from adsorbed gases determines the thermal conductivity of ZIFs. It is found that the increased thermal conductivity with the increased number of adsorbed gases is correlated with the overlap energy between the vibrational density of states of gases and Zn atoms, suggesting the additional heat transfer pathways formed between gas molecules and frameworks. Moreover, the gas spatial distribution and diffusion also impose remarkable impacts on the heat transfer performance. Both the homogeneous gas distribution and the fast gas diffusion are conducive to form effective heat transfer pathways, leading to enhanced thermal conductivity. This study provides molecular insight into the mechanism of the improved thermal conductivity of ZIFs upon gas adsorption, which may pave the way for effective thermal management in MOF-related applications.

18.
J Agric Food Chem ; 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37812565

RESUMO

Bioactive peptides from foods have garnered considerable attention as viable supplements for hypertensive patients. Herein, the antihypertensive effect and mechanism of umami peptides from yeast extract were investigated based on the pharmacophore model, simulated digestion, spontaneously hypertensive rat (SHR) model, and molecular docking. Notably, umami peptide LLLLPKP exhibited favorable angiotensin I-converting enzyme (ACE) inhibitory activity (IC50 = 10.22 µM) in vitro and regulated blood pressure in the SHR model with excellent durability. Remarkably, LLLLPKP showed the highest Fitvalue (4.022) of the pharmacophore model, indicating its similar pharmacological effects as ACE inhibitors. During the simulated gastrointestinal digestion, the ACE inhibition rate of LLLLPKP was merely reduced by 5.89%, but it was enzymatically cleaved into 14 peptide segments. The C-terminal sequence comprising L (4), P (5), K (6), and P (7) exhibited robust stability and a notable presence within the peptide segments postdigestion. Meanwhile, according to molecular docking, these four residues within LLLLPKP were responsible for all interactions with key sites within active pockets S1 and S2 and the active pocket of Zn2+. In light of these findings, LLLLPKP is a highly promising antihypertensive peptide. Developing this umami peptide with antihypertensive effects holds substantial importance for the long-term treatment of hypertension.

19.
BMC Musculoskelet Disord ; 24(1): 711, 2023 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-37674188

RESUMO

BACKGROUND: The purpose of this study was to measure the femoral prosthesis flexion angle (FPFA) in total knee arthroplasty (TKA) using three-dimensional reconstruction, and to assess the differences in early clinical efficacy between patients with different degrees of flexion. METHODS: We conducted a prospective cohort study. From June 2019 to May 2021, 113 patients admitted for TKA due to osteoarthritis of the knee were selected. The patients' postoperative knee joints were reconstructed in three dimensions according to postoperative three-dimensional computed tomography (CT) scans. The FPFA was measured, and the patients were divided into 4 groups: anterior extension group (FPFA < 0°), mildly flexed group (0° ≤ FPFA < 3°), moderately flexed group (3° ≤ FPFA < 6°) and excessively flexed group (6° ≤ FPFA). The differences in the Knee Society Score (KSS), knee Range of Motion (ROM), and visual analogue scale (VAS) scores were measured and compared between the four groups at each postoperative time point. RESULTS: Postoperative KSS, ROM, and VAS were significantly improved in all groups compared to the preoperative period. At 1 year postoperatively, the ROM was significantly greater in the mildly flexed group (123.46 ± 6.51°) than in the anterior extension group (116.93 ± 8.05°) and the excessively flexed group (118.76 ± 8.20°) (P < 0.05). The KSS was significantly higher in the mildly flexed group (162.68 ± 12.79) than in the other groups at 6 months postoperatively (P < 0.05). The higher KSS (174.17 ± 11.84) in the mildly flexed group was maintained until 1 year postoperatively, with a statistically significant difference (P < 0.05). No significant difference in VAS scores was observed between groups at each time point. CONCLUSIONS: A femoral prosthesis flexion angle of 0-3° significantly improved postoperative knee mobility, and patients could obtain better Knee Society Scores after surgery, which facilitated the postoperative recovery of knee function. TRIAL REGISTRATION: ChiCTR2100051502, 2021/09/24.


Assuntos
Artroplastia do Joelho , Membros Artificiais , Humanos , Artroplastia do Joelho/efeitos adversos , Estudos Prospectivos , Fêmur/diagnóstico por imagem , Fêmur/cirurgia , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia
20.
Adv Mater ; : e2306480, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37555527

RESUMO

Constructing atomic catalytic pair emerges as an attractive strategy to achieve better catalytic performance. Herein, an atomic Ir1 ─P1 /NPG catalyst with asymmetric Ir─N2 P1 sites that delivers superb activity and selectivity for hydrogenation of various functionalized nitrostyrene is reported. In the hydrogenation reaction of 3-nitrostyrene, Ir1 ─P1 /NPG (NPG refers to N, P-codoped graphene) shows a turnover frequency of 1197 h-1 , while the reaction cannot occur over Ir1 /NG (NG refers to N-doped graphene). Compared to Ir1 /NG, the charge density of the Ir site in Ir1 ─P1 /NPG is greatly elevated, which is conducive to H2 dissociation. Moreover, as revealed by density functional theory calculations and poisoning experiments, the P site in Ir1 ─P1 /NPG is found able to bind nitrostyrene, while the neighboring Ir site provides H to reduce the nitro group in chemoselective hydrogenation of nitrostyrene. This work offers a successful example of establishing atomic catalytic pair for driving important chemical reactions, paving the way for the development of more advanced catalysts to further improve the catalytic performance.

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