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1.
J Biol Chem ; 299(5): 104670, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37024091

RESUMO

Nonphotochemical quenching (NPQ) is an important photoprotective mechanism that quickly dissipates excess light energy as heat. NPQ can be induced in a few seconds to several hours; most studies of this process have focused on the rapid induction of NPQ. Recently, a new, slowly induced form of NPQ, called qH, was found during the discovery of the quenching inhibitor suppressor of quenching 1 (SOQ1). However, the specific mechanism of qH remains unclear. Here, we found that hypersensitive to high light 1 (HHL1)-a damage repair factor of photosystem II-interacts with SOQ1. The enhanced NPQ phenotype of the hhl1 mutant is similar to that of the soq1 mutant, which is not related to energy-dependent quenching or other known NPQ components. Furthermore, the hhl1 soq1 double mutant showed higher NPQ than the single mutants, but its pigment content and composition were similar to those of the wildtype. Overexpressing HHL1 decreased NPQ in hhl1 to below wildtype levels, whereas NPQ in hhl1 plants overexpressing SOQ1 was lower than that in hhl1 but higher than that in the wildtype. Moreover, we found that HHL1 promotes the SOQ1-mediated inhibition of plastidial lipoprotein through its von Willebrand factor type A domain. We propose that HHL1 and SOQ1 synergistically regulate NPQ.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Temperatura Alta , Luz , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Mutação , Fotoquímica , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Plastídeos/metabolismo , Domínios Proteicos , Fator de von Willebrand/química
2.
Small ; 20(44): e2404581, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38989685

RESUMO

Printing technology enables the integration of chemically exfoliated perovskite nanosheets into high-performance microcapacitors. Theoretically, the capacitance value can be further enhanced by designing and constructing multilayer structures without increasing the device size. Yet, issues such as interlayer penetration in multilayer heterojunctions constructed using inkjet printing technology further limit the realization of this potential. Herein, a series of multilayer configurations, including Ag/(Ca2NaNb4O13/Ag)n and graphene/(Ca2NaNb4O13/graphene)n (n = 1-3), are successfully inkjet-printed onto diverse rigid and flexible substrates through optimized ink formulations, inkjet printing parameters, thermal treatment conditions, and rational multilayer structural design using high-k perovskite nanosheets, graphene nanosheets and silver. The dielectric performance is optimized by fine-tuning the number of dielectric layers and modifying the electrode/dielectric interface. As a result, the graphene/(Ca2NaNb4O13/graphene)3 multilayer ceramic capacitors exhibit a remarkable capacitance density of 346 ± 12 nF cm-2 and a high dielectric constant of 193 ± 18. Additionally, these devices demonstrate moderate insulation properties, flexibility, thermal stability, and chemical sensitivity. This work shed light on the potential of multilayer structural design in additive manufacturing of high-performance 2D material-based ceramic capacitors.

3.
Small ; 20(4): e2305782, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37718497

RESUMO

Due to their unique electronic and structural properties, single-atom catalytic materials (SACMs) hold great promise for the oxygen reduction reaction (ORR). Coordinating environmental and engineering strategies is the key to improving the ORR performance of SACMs. This review summarizes the latest research progress and breakthroughs of SACMs in the field of ORR catalysis. First, the research progress on the catalytic mechanism of SACMs acting on ORR is reviewed, including the latest research results on the origin of SACMs activity and the analysis of pre-adsorption mechanism. The study of the pre-adsorption mechanism is an important breakthrough direction to explore the origin of the high activity of SACMs and the practical and theoretical understanding of the catalytic process. Precise coordination environment modification, including in-plane, axial, and adjacent site modifications, can enhance the intrinsic catalytic activity of SACMs and promote the ORR process. Additionally, several engineering strategies are discussed, including multiple SACMs, high loading, and atomic site confinement. Multiple SACMs synergistically enhance catalytic activity and selectivity, while high loading can provide more active sites for catalytic reactions. Overall, this review provides important insights into the design of advanced catalysts for ORR.

4.
Nat Mater ; 22(9): 1106-1113, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37537356

RESUMO

Non-collinear antiferromagnets are an emerging family of spintronic materials because they not only possess the general advantages of antiferromagnets but also enable more advanced functionalities. Recently, in an intriguing non-collinear antiferromagnet Mn3Sn, where the octupole moment is defined as the collective magnetic order parameter, spin-orbit torque (SOT) switching has been achieved in seemingly the same protocol as in ferromagnets. Nevertheless, it is fundamentally important to explore the unknown octupole moment dynamics and contrast it with the magnetization vector of ferromagnets. Here we report a handedness anomaly in the SOT-driven dynamics of Mn3Sn: when spin current is injected, the octupole moment rotates in the opposite direction to the individual moments, leading to a SOT switching polarity distinct from ferromagnets. By using second-harmonic and d.c. magnetometry, we track the SOT effect onto the octupole moment during its rotation and reveal that the handedness anomaly stems from the interactions between the injected spin and the unique chiral-spin structure of Mn3Sn. We further establish the torque balancing equation of the magnetic octupole moment and quantify the SOT efficiency. Our finding provides a guideline for understanding and implementing the electrical manipulation of non-collinear antiferromagnets, which in nature differs from the well-established collinear magnets.

5.
Macromol Rapid Commun ; : e2400518, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39101702

RESUMO

Hydrogel devices with mechanical toughness and tunable functionalities are highly desirable for practical long-term applications such as sensing and actuation elements for soft robotics. However, existing hydrogels have poor mechanical properties, slow rates of response, and low functionality. In this work, two-dimensional hydrogel actuators are proposed and formed on the self-assembly of graphene oxide (GO) and deoxynucleic acid (DNA). The self-assembly process is driven by the GO-induced transition of double stranded DNA (dsDNA) into single stranded DNA (ssDNA). Thus, the hydrogel's structural unit consists of two layers of GO covered by ssDNA and a layer of dsDNA in between. Such heterogeneous architectures stabilized by multiple hydrogen bondings have Young's modulus of up to 10 GPa and rapid swelling rates of 4.0 × 10-3 to 1.1 × 10-2 s-1, which surpasses most types of conventional hydrogels. It is demonstrated that the GO/DNA hydrogel actuators leverage the unique properties of these two materials, making them excellent candidates for various applications requiring sensing and actuation functions, such as artificial skin, wearable electronics, bioelectronics, and drug delivery systems.

6.
Altern Ther Health Med ; 30(9): 241-249, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38290442

RESUMO

Background: Coronary atherosclerosis is a serious and progressive condition characterized by the accumulation of plaques, consisting of fat, cholesterol, and other substances, within the arteries that supply blood to the heart. These plaques can harden and narrow the arteries, leading to reduced blood flow to the heart muscle. Objective: The primary objective of this study is to investigate the correlation between specific cardiovascular parameters and intracoronary vascular ultrasound indexes in patients diagnosed with coronary heart disease. This investigation aims to explore the relationships between intracoronary vascular ultrasound measurements and three key cardiovascular parameters: epicardial fat pad thickness, mono-platelet polymer levels, and small dense low-density lipoprotein cholesterol (sdLDL-C) levels. Methods: In this investigation, we applied a comprehensive method to evaluate atherosclerotic plaque characteristics in patients with diverse stages of coronary heart disease (CHD), contrasting these profiles with those of healthy individuals. Our study included 80 acute myocardial infarction (AMI) patients, 145 with unstable angina pectoris (UAP), 175 with stable angina pectoris (SAP), and 100 controls. We utilized intravascular ultrasound (IVUS), an advanced imaging technique that surpasses traditional angiography by providing detailed, high-resolution images of both the coronary artery lumen and wall, including plaque composition. This approach is pivotal for assessing plaque stability, a key factor in the risk of rupture and subsequent cardiovascular events, indicated by features like lipid-rich cores and thin fibrous caps. During IVUS, we quantified parameters such as plaque area, load, and the remodeling index, the latter offering insights into vascular adaptation to plaque buildup. Additionally, we conducted a correlation analysis between IVUS indices and three cardiovascular markers: epicardial fat pad thickness, monocyte-platelet aggregates, and sdLDL-C levels. The goal was to ascertain the predictive value of these markers in tandem with IVUS for determining the stability of coronary artery atherosclerotic plaques. This integrative approach enhances understanding of plaque formation and destabilization, potentially informing more effective CHD prevention and management strategies. Results: Our study revealed distinct variations in key parameters across patient groups with different forms of CHD and healthy controls. Notably, we observed significant differences in gender distribution, hypertension, and diabetes mellitus prevalence among these groups. In terms of IVUS indexes and cardiovascular parameters, the SAP group exhibited markedly different results compared to the AMI and UAP groups. Specifically, the SAP patients showed the lowest values for EMMA, plaque area, plaque burden, reconstruction index, and positive remodeling. Additionally, they exhibited the thickest fibrous caps. In contrast, the AMI and UAP groups presented similar outcomes in these aspects. Regarding the epicardial fat pad thickness, the positive rate of monocyte-platelet aggregates, and the levels of sdLDL-C, there were no significant differences between the AMI and UAP groups. However, these parameters were notably higher in the AMI and UAP groups compared to the SAP group. Crucially, we established a significant correlation between the thickness of the epicardial fat pad, the positive rate of monocyte-platelet aggregates, and the sdLDL-C levels with plaque loading rate and remodeling index. These correlations underscore the potential utility of these parameters as indicators of plaque stability and cardiovascular risk in patients with CHD. This highlights the complexity of atherosclerotic disease progression and underscores the importance of a multifaceted approach to assessing and managing CHD. Conclusion: Our research delineates the critical role of the remodeling index, epicardial fat pad thickness, monocyte-platelet aggregates, and sdLDL-C levels as key prognostic tools for assessing coronary plaque stability in coronary artery disease (CAD). These biomarkers collectively provide an enhanced perspective on plaque vulnerability, an essential aspect in the genesis of acute coronary events. Clinically, these findings are pivotal. They offer a refined approach to CAD management and risk evaluation, allowing for the precise identification of patients at increased risk of plaque rupture, a precursor to acute coronary syndromes. This precision facilitates the adoption of more individualized treatment strategies, focusing on aggressive interventions for high-risk patients and more conservative management for those with stable plaques.


Assuntos
Ultrassonografia de Intervenção , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Ultrassonografia de Intervenção/métodos , Placa Aterosclerótica/diagnóstico por imagem , Doença da Artéria Coronariana/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/fisiopatologia , Doença das Coronárias/diagnóstico por imagem , LDL-Colesterol/sangue
7.
Small ; : e2307662, 2023 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-38072770

RESUMO

The problem in d-band center modulation of transition metal-based catalysts for the rate-determining steps of oxygen conversion is an obstacle to boost the electrocatalytic activity by accelerating proton coupling. Herein, the Co doping to FeP is adopted to modify the d-band center of Fe. Optimized Fe sites accelerate the proton coupling of oxygen reduction reaction (ORR) on N-doped wood-derived carbon through promoting water dissociation. In situ generated Fe sites optimize the adsorption of oxygen-related intermediates of oxygen evolution reaction (OER) on CoFeP NPs. Superior catalytic activity toward ORR (half-wave potential of 0.88 V) and OER (overpotential of 300 mV at 10 mA cm-2 ) express an unprecedented level in carbon-based transition metal-phosphide catalysts. The liquid zinc-air battery presents an outstanding cycling stability of 800 h (2400 cycles). This research offers a newfangled perception on designing highly efficient carbon-based bifunctional catalysts for ORR and OER.

8.
Chem Soc Rev ; 51(24): 10016-10063, 2022 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-36398768

RESUMO

Electronic doping is applied to tailor the electrical and optoelectronic properties of semiconductors, which have been widely adopted in information and clean energy technologies, like integrated circuit fabrication and PVs. Though this concept has prevailed in conventional PVs, it has achieved limited success in the new-generation PV materials, particularly in halide perovskites, owing to their soft lattice nature and self-compensation by intrinsic defects. In this review, we summarize the evolution of the theoretical understanding and strategies of electronic doping from Si-based photovoltaics to thin-film technologies, e.g., GaAs, CdTe and Cu(In,Ga)Se2, and also cover the emerging PVs including halide perovskites and organic solar cells. We focus on the chemical approaches to electronic doping, emphasizing various chemical interactions/bonding throughout materials synthesis/modification to device fabrication/operation. Furthermore, we propose new classifications and models of electronic doping based on the physical and chemical properties of dopants, in the context of solid-state chemistry, which inspires further development of optoelectronics based on perovskites and other hybrid materials. Finally, we outline the effects of electronic doping in semiconducting materials and highlight the challenges that need to be overcome for reliable and controllable doping.

9.
Small ; 18(34): e2202725, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35871557

RESUMO

Oxygen reduction reaction (ORR) is the key reaction on cathode of rechargeable zinc-air batteries (ZABs). However, the lack of protons in alkaline conditions limits the rate of ORR. Herein, an activating water strategy is proposed to promote oxygen electrocatalytic activity by enhancing the proton production from water dissociation. FeP nanoparticles (NPs) are coupled on N-doped wood-derived catalytically active carbon (FeP-NWCC) to associate bifunctional active sites. In alkaline, FeP-NWCC possesses outstanding catalytic activities toward ORR (E1/2  = 0.86 V) and Oxygen evolution reaction (OER) (overpotential is 310 mV at 10 mA cm-2 ). The liquid ZABs assembled by FeP-NWCC deliver superior peak power density (144 mW cm-2 ) and cycle stability (over 450 h). The quasi-solid-state ZABs based on FeP-NWCC also display excellent performances. Theoretical calculation illustrates that the superb bifunctional performance of FeP-NWCC results from the elevated dissociation efficiency of water via FeP NPs to assist the oxygen catalytic process. The strategy of activating water provides a new perspective for the design of ORR/OER bifunctional catalysts. This work is a model for the application of forest biomass.


Assuntos
Oxigênio , Água , Catálise , Fontes de Energia Elétrica , Oxigênio/química , Prótons , Madeira , Zinco/química
10.
Small ; 18(26): e2202014, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35644887

RESUMO

Electrochemical reduction of oxygen plays a critical role in emerging electrochemical energy technologies. Multiple electron transfer processes, involving adsorption and activation of O2 and generation of protons from water molecules, cause the sluggish kinetics of the oxygen reduction reaction (ORR). Herein, a double-active-site catalyst of Fe3 C nanoparticles coupled to paulownia wood-derived N-doped carbon (Fe3 C@NPW) is fabricated via an active-site-uniting strategy. One site on Fe3 C nanoparticles contributes to activating water molecules, while another site on N-doped carbon is responsible for activating oxygen molecules. Benefiting from the synergistic effect of double active sites, Fe3 C@NPW delivers a remarkable catalytic activity for ORR with a half-wave potential of 0.87 V (vs. RHE) in alkaline electrolyte, outperforming commercial Pt/C catalyst. Moreover, zinc-air batteries (ZABs) assembled with Fe3 C@NPW as a catalyst on cathode achieve a large specific capacity of 804.4 mA h gZn-1 and a long-term stability of 780 cycles. The model solid-state ZABs also display satisfactory performances with an open-circuit voltage of 1.39 V and a high peak power density of 78 mW cm-2 . These outstanding performances reach the level of first-rank among the non-noble metal electrode materials. This work offers a promising approach to creating double-active-site catalysts by the active-site-uniting strategy for energy conversion fields.


Assuntos
Carbono , Nanopartículas , Eletrodos , Hipóxia , Oxigênio , Água , Madeira , Zinco
11.
Small ; 18(16): e2107087, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35274448

RESUMO

MXenes have exhibited potential for application in flexible devices owing to their remarkable electronic, optical, and mechanical properties. Printing strategies have emerged as a facile route for additive manufacturing of MXene-based devices, which relies on the rational design of functional inks with appropriate rheological properties. Herein, aqueous MXene/xanthan gum hybrid inks with tunable viscosity, excellent printability, and long-term stability are designed. Screen-printed flexible MXene films using such hybrid inks exhibit a high conductivity up to 4.8 × 104  S m-1 , which is suitable to construct multifunctional devices mainly including electromagnetic shielding, Joule heaters, and piezoresistive sensors. The average electromagnetic interference (EMI) shielding value can reach to 40.1 dB. In the Joule heater, the heating rate of printed MXene film can reach 20 °C s-1 under a driving voltage of 4 V, with a highest steady-state temperature of 130.8 °C. An MXene-based piezoresistive sensor prepared by the printing interdigital electrode also presents good sensing performance with a short response time of 130 ms and wide pressure region up to 30 kPa. As a result, screen-printed MXene film exhibits reinforced multifunctional performance, which is promising for application in the next-generation of intelligent and wearable devices.

12.
Appl Environ Microbiol ; 88(3): e0185121, 2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-34851722

RESUMO

Dietary polyphenols can significantly benefit human health, but their bioavailability is metabolically controlled by human gut microbiota. To facilitate the study of polyphenol metabolism for human gut health, we have manually curated experimentally characterized polyphenol utilization proteins (PUPs) from published literature. This resulted in 60 experimentally characterized PUPs (named seeds) with various metadata, such as species and substrate. Further database search found 107,851 homologs of the seeds from UniProt and UHGP (unified human gastrointestinal protein) databases. All PUP seeds and homologs were classified into protein classes, families, and subfamilies based on Enzyme Commission (EC) numbers, Pfam (protein family) domains, and sequence similarity networks. By locating PUP homologs in the genomes of UHGP, we have identified 1,074 physically linked PUP gene clusters (PGCs), which are potentially involved in polyphenol metabolism in the human gut. The gut microbiome of Africans was consistently ranked the top in terms of the abundance and prevalence of PUP homologs and PGCs among all geographical continents. This reflects the fact that dietary polyphenols are consumed by the African population more commonly than by other populations, such as Europeans and North Americans. A case study of the Hadza hunter-gatherer microbiome verified the feasibility of using dbPUP to profile metagenomic data for biologically meaningful discovery, suggesting an association between diet and PUP abundance. A Pfam domain enrichment analysis of PGCs identified a number of putatively novel PUP families. Lastly, a user-friendly web interface (https://bcb.unl.edu/dbpup/) provides all the data online to facilitate the research of polyphenol metabolism for improved human health. IMPORTANCE Long-term consumption of polyphenol-rich foods has been shown to lower the risk of various human diseases, such as cardiovascular diseases, cancers, and metabolic diseases. Raw polyphenols are often enzymatically processed by gut microbiome, which contains various polyphenol utilization proteins (PUPs) to produce metabolites with much higher bioaccessibility to gastrointestinal cells. This study delivered dbPUP as an online database for experimentally characterized PUPs and their homologs in human gut microbiome. This work also performed a systematic classification of PUPs into enzyme classes, families, and subfamilies. The signature Pfam domains were identified for PUP families, enabling conserved domain-based PUP annotation. This standardized sequence similarity-based PUP classification system offered a guideline for the future inclusion of new experimentally characterized PUPs and the creation of new PUP families. An in-depth data analysis was further conducted on PUP homologs and physically linked PUP gene clusters (PGCs) in gut microbiomes of different human populations.


Assuntos
Microbioma Gastrointestinal , Microbiota , Trato Gastrointestinal/metabolismo , Humanos , Metagenoma , Polifenóis/metabolismo
13.
Phys Rev Lett ; 129(1): 017203, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35841567

RESUMO

Injecting spin currents into antiferromagnets and realizing efficient spin-orbit-torque switching represents a challenging topic. Because of the diminishing magnetic susceptibility, current-induced antiferromagnetic dynamics remain poorly characterized, complicated by spurious effects. Here, by growing a thin film antiferromagnet, α-Fe_{2}O_{3}, along its nonbasal plane orientation, we realize a configuration where the spin-orbit torque from an injected spin current can unambiguously rotate and switch the Néel vector within the tilted easy plane, with an efficiency comparable to that of classical ferrimagnetic insulators. Our study introduces a new platform for quantitatively characterizing switching and oscillation dynamics in antiferromagnets.

14.
Nano Lett ; 21(16): 7037-7043, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34374550

RESUMO

Unequal transmissions of spin waves along opposite directions provide useful functions for signal processing. So far, the realization of such nonreciprocal spin waves has been mostly limited at a gigahertz frequency in the coherent regime via microwave excitation. Here we show that, in a magnetic bilayer stack with chiral coupling, tunable nonreciprocal propagation can be realized in spin Hall effect-excited incoherent magnons, whose frequencies cover the spectrum from a few gigahertz up to terahertz. The sign of nonreciprocity is controlled by the magnetic orientations of the bilayer in a nonvolatile manner. The nonreciprocity is further verified by measurements of the magnon diffusion length, which is unequal along opposite transmission directions. Our findings enrich the knowledge on magnetic relaxation and diffusive transport and can lead to the design of a passive directional signal isolation device in the diffusive regime.

15.
Nano Lett ; 20(5): 3864-3871, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32353241

RESUMO

The commonly employed formamidinium (FA)-containing perovskite solar cells (PSCs) exhibit a severe phase instability problem, thereby limiting their commercial applications. Here, both phase stability and energy efficiency of FA-based PSCs were improved by treating the perovskite surface with pyrrolidinium hydroiodide (PyI) salts, resulting in a 1D perovskite structure (PyPbI3), stacked on the original 3D perovskite. By employing in situ XRD measurements, we revealed that the temperature-dependent phase transition activation barrier was enhanced after forming the 1D/3D structure, resulting in a prolonged transition time by 30-40-fold. From the first-principle calculations, we found the thermodynamic energy difference between two phases reduced from -0.16 to -0.04 eV after the stacking of 1D PyPbI3, offering additional lifetime improvement. Moreover, the champion 1D/3D bilayer PSC exhibits a boosted power conversion efficiency of 19.62%, versus 18.21% of the control. Such 1D/3D bilayer structure may be employed in PSCs to enhance their phase stability and photovoltaic performance.

16.
Phys Rev Lett ; 123(24): 247206, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31922833

RESUMO

A quantitative investigation of the current-induced torque in antiferromagnets represents a great challenge due to the lack of an independent method for controlling Néel vectors. By utilizing an antiferromagnetic insulator with the Dzyaloshinskii-Moriya interaction α-Fe_{2}O_{3}, we show that the Néel vector can be controlled with a moderate external field, which is further utilized to calibrate the current-induced magnetic dynamics. We find that the current-induced magnetoresistance change in antiferromagnets can be complicated by resistive switching that does not have a magnetic origin. By excluding nonmagnetic switching and comparing the current-induced dynamics with the field-induced one, we determine the nature and magnitude of current-induced effects in Pt/α-Fe_{2}O_{3} bilayer films.

17.
Phys Rev Lett ; 123(4): 047204, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31491278

RESUMO

We report broadband microwave absorption spectroscopy of the layered antiferromagnet CrCl_{3}. We observe a rich structure of resonances arising from quasi-two-dimensional antiferromagnetic dynamics. Because of the weak interlayer magnetic coupling in this material, we are able to observe both optical and acoustic branches of antiferromagnetic resonance in the GHz frequency range and a symmetry-protected crossing between them. By breaking rotational symmetry, we further show that strong magnon-magnon coupling with large tunable gaps can be induced between the two resonant modes.

18.
Org Biomol Chem ; 17(26): 6461-6464, 2019 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-31218327

RESUMO

An efficient iridium-catalyzed intramolecular enantioselective allylation of quinazolin-4(3H)-one derivatives has been developed, and the corresponding products were obtained with high reactivity and high to excellent enantioselectivity with tolerance of some functional groups, in which our developed chiral cyclic phosphoramidite ligands greatly promoted the iridium-catalyzed reactivity and enantioselectivity.

19.
Chemistry ; 22(48): 17477-17484, 2016 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-27735100

RESUMO

A new type of axially chiral cyclo-[1,1'-biphenyl]-2,2'-diol (CYCNOL) ligands with adjustable dihedral angles have been developed by varying the bridge chain length. Eight-, nine- and ten-membered cyclo-ligands were prepared and evaluated by using two representative examples: enantioselective additions of diethylzinc to aldehydes and organometallic reagents to enones. The results revealed that the fine regulation of dihedral angles through variation of the bridge chain length was effective in the asymmetric synthesis.

20.
Mol Divers ; 18(3): 593-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24664285

RESUMO

Based on structures of insecticidal chlorfenapyr and antibiotic natural pyrrolomycins, a series of new 2-benzylpyrroles and 2-benzoylpyrroles (with or without ethoxymethyl group on the nitrogen of pyrrole) were designed and synthesized. These compounds or their parent compounds possess weak acidity and high lipophilicity, the two characteristic properties for uncouplers of oxidative phosphorylation; therefore, they are expected to have insecticidal and acaricidal activity. The bioassay result verified that both 2-benzylpyrroles 17 and 2-benzoylpyrroles 19 had varied degrees of insecticidal activity against oriental armyworm depending on the substituents on the benzene ring, but they did not give any acaricidal activity. Conversely, most N-alkylated compounds 18 and 20 exhibited both insecticidal activity and acaricidal activity, of which compound 18i [4-bromo-2-(2,4-dichlorobenzyl)-1-(ethoxymethyl) -5-(trifluoromethyl) -1H-pyrrole-3-carbonitrile] has IC50 as low as 10-20 mg L(-1) on both activities.


Assuntos
Produtos Biológicos/química , Desenho de Fármacos , Piretrinas/química , Pirróis/química , Pirróis/síntese química , Acaricidas/síntese química , Acaricidas/química , Animais , Antifúngicos/síntese química , Antifúngicos/química , Técnicas de Química Sintética , Fungos/efeitos dos fármacos , Inseticidas/síntese química , Inseticidas/química , Lepidópteros , Relação Estrutura-Atividade , Tetranychidae
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