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1.
Plant Cell Environ ; 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38988259

RESUMEN

Loss of Lon1 led to stunted plant growth and accumulation of nuclear-encoded mitochondrial proteins including Lon1 substrates. However, an in-depth label-free proteomics quantification of mitochondrial proteins in lon1 revealed that the majority of mitochondrial-encoded proteins decreased in abundance. Additionally, we found that lon1 mutants contained protein aggregates in the mitochondrial that were enriched in metabolic enzymes, ribosomal subunits and PPR-containing proteins of the translation apparatus. These mutants exhibited reduced general mitochondrial translation as well as deficiencies in RNA splicing and editing. These findings support the role of Lon1 in maintaining a functional translational apparatus for mitochondrial-encoded gene translation. Transcriptome analysis of lon1 revealed a mitochondrial unfolded protein response reminiscent of the mitochondrial retrograde signalling dependent on the transcription factor ANAC017. Notably, lon1 mutants exhibited transiently elevated ethylene production, and the shortened hypocotyl observed in lon1 mutants during skotomorphogenesis was partially alleviated by ethylene inhibitors. Furthermore, the short root phenotype was partially ameliorated by introducing a mutation in the ethylene receptor ETR1. Interestingly, the upregulation of only a select few target genes was linked to ETR1-mediated ethylene signalling. Together this provides multiple steps in the link between loss of Lon1 and signalling responses to restore mitochondrial protein homoeostasis in plants.

2.
Opt Lett ; 49(10): 2805-2808, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38748166

RESUMEN

The advancement demands of high-speed wireless data link ask for higher requirements on visible light communication (VLC), where wide coverage stands as a critical criterion. Here, we present the design and implementation of a transmitter structure capable of emitting a high-power wide-coverage white light laser. This laser source exhibits excellent stability, with an irradiation range extending to a half-angle of 20°. Its high brightness satisfies the needs of indoor illumination while maintaining excellent communication performance. Utilizing bit-loading discrete multi-tone modulation, a peak data transmission rate of 3.24 Gbps has been achieved, spanning 1 to 5 m. Remarkably, the data rates exceed 2.5 Gbps within a 40° range at a distance of 5 m, enabling a long-distance, wide coverage, high-speed VLC link for future mobile network applications.

3.
Sensors (Basel) ; 24(10)2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38793940

RESUMEN

Mobile visible light communication (VLC) is key for integrating lighting and communication applications in the 6G era, yet there exists a notable gap in experimental research on mobile VLC. In this study, we introduce a mobile VLC system and investigate the impact of mobility speed on communication performance. Leveraging a laser-based light transmitter with a wide coverage, we enable a light fidelity (LiFi) system with a mobile receiving end. The system is capable of supporting distances from 1 m to 4 m without a lens and could maintain a transmission rate of 500 Mbps. The transmission is stable at distances of 1 m and 2 m, but an increase in distance and speed introduces interference to the system, leading to a rise in the Bit Error Rate (BER). The mobile VLC experimental system provides a viable solution to the issue of mobile access in the integration of lighting and communication applications, establishing a solid practical foundation for future research.

4.
Int J Mol Sci ; 25(10)2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38791463

RESUMEN

Mitochondrial protein homeostasis is crucially regulated by protein degradation processes involving both mitochondrial proteases and cytosolic autophagy. However, it remains unclear how plant cells regulate autophagy in the scenario of lacking a major mitochondrial Lon1 protease. In this study, we observed a notable downregulation of core autophagy proteins in Arabidopsis Lon1 knockout mutant lon1-1 and lon1-2, supporting the alterations in the relative proportions of mitochondrial and vacuolar proteins over total proteins in the plant cells. To delve deeper into understanding the roles of the mitochondrial protease Lon1 and autophagy in maintaining mitochondrial protein homeostasis and plant development, we generated the lon1-2atg5-1 double mutant by incorporating the loss-of-function mutation of the autophagy core protein ATG5, known as atg5-1. The double mutant exhibited a blend of phenotypes, characterized by short plants and early senescence, mirroring those observed in the individual single mutants. Accordingly, distinct transcriptome alterations were evident in each of the single mutants, while the double mutant displayed a unique amalgamation of transcriptional responses. Heightened severity, particularly evident in reduced seed numbers and abnormal embryo development, was observed in the double mutant. Notably, aberrations in protein storage vacuoles (PSVs) and oil bodies were evident in the single and double mutants. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of genes concurrently downregulated in lon1-2, atg5-1, and lon1-2atg5-1 unveiled a significant suppression of genes associated with brassinosteroid (BR) biosynthesis and homeostasis. This downregulation likely contributes to the observed abnormalities in seed and embryo development in the mutants.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Autofagia , Brasinoesteroides , Regulación de la Expresión Génica de las Plantas , Mitocondrias , Semillas , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Autofagia/genética , Semillas/crecimiento & desarrollo , Semillas/genética , Semillas/metabolismo , Mitocondrias/metabolismo , Brasinoesteroides/metabolismo , Proteasas ATP-Dependientes/metabolismo , Proteasas ATP-Dependientes/genética , Mutación , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Regulación hacia Abajo , Fenotipo , Serina Endopeptidasas
5.
Angew Chem Int Ed Engl ; : e202407355, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38837587

RESUMEN

The structure of molecular aggregates is crucial for charge transport and photovoltaic performance in organic solar cells (OSCs). Herein, the intermolecular interactions and aggregated structures of nonfused-ring electron acceptors (NFREAs) are precisely regulated through a halogen transposition strategy, resulting in a noteworthy transformation from a 2D-layered structure to a 3D-interconnected packing network. Based on the 3D electron transport pathway, the binary and ternary devices deliver outstanding power conversion efficiencies (PCEs) of 17.46 % and 18.24 %, respectively, marking the highest value for NFREA-based OSCs.

6.
Angew Chem Int Ed Engl ; 63(10): e202318143, 2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38190621

RESUMEN

In the development of high-performance organic solar cells (OSCs), the self-organization of organic semiconductors plays a crucial role. This study focuses on the precisely manipulation of molecular assemble via tuning alkyl side-chain topology in a series of low-cost nonfused-ring electron acceptors (NFREAs). Among the three NFREAs investigated, DPA-4, which possesses an asymmetric alkyl side-chain length, exhibits a tight packing in the crystal and high crystallinity in the film, contributing to improved electron mobility and favorable film morphology for DPA-4. As a result, the OSC device based on DPA-4 achieves an excellent power conversion efficiency of 16.67 %, ranking among the highest efficiencies for NFREA-based OSCs.

7.
J Am Chem Soc ; 145(22): 11988-11996, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37166280

RESUMEN

All-photonic synaptic devices with the merits of visible signals and high spatiotemporal resolution are promising to break the Von Neumann bottleneck. Although organic synapses outperform their inorganic counterpart for easy molecular modulation and lower energy consumption, the organic all-photonic artificial synapse has never been reported. Here, all-photonic synaptic characteristics were unprecedentedly observed in an organic semiconductor, (3,6-dimethyl-9H-carbazol-9-yl)(thiophen-2-yl) methanone (S2OC), with anti-Stokes photoluminescence. Impressively, the intensity of fluorescence from the higher excited state (S3) exhibited synaptic performance, which constantly increased with irradiation time through a channel composed of intersystem crossing, triplet-triplet annihilation, and energy transfer. More importantly, the relationship between the molecular structure and synaptic performance was established. Based on the synaptic photoplasticity property, noncontacted multilevel anticounterfeiting and imaging recognition were realized in all-photonic synapse arrays. This work provides a universal strategy for tuning the performances of organic synapses upon regulating the molecular structures, which paves the way for the application of organic semiconductors in artificial intelligence.

8.
Plant J ; 103(4): 1575-1589, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32433816

RESUMEN

Arabidopsis thaliana AKR2A plays an important role in plant responses to cold stress. However, its exact function in plant resistance to cold stress remains unclear. In the present study, we found that the contents of very long-chain fatty acids (VLCFAs) in akr2a mutants were decreased, and the expression level of KCS1 was also reduced. Overexpression of KCS1 in the akr2a mutants could enhance VLCFAs contents and chilling tolerance. Yeast-2-hybrid and bimolecular fluorescence complementation (BIFC) results showed that the transmembrane motif of KCS1 interacts with the PEST motif of AKR2A both in vitro and in vivo. Overexpression of KCS1 in akr2a mutants rescued akr2a mutant phenotypes, including chilling sensitivity and a decrease of VLCFAs contents. Moreover, the transgenic plants co-overexpressing AKR2A and KCS1 exhibited a greater chilling tolerance than the plants overexpressing AKR2A or KCS1 alone, as well as the wild-type. AKR2A knockdown and kcs1 knockout mutants showed the worst performance under chilling conditions. These results indicate that AKR2A is involved in chilling tolerance via an interaction with KCS1 to affect VLCFA biosynthesis in Arabidopsis.


Asunto(s)
Acetiltransferasas/fisiología , Proteínas de Arabidopsis/fisiología , Ácidos Grasos/metabolismo , Chaperonas Moleculares/fisiología , Acetiltransferasas/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Frío/efectos adversos , Respuesta al Choque por Frío , Ácidos Grasos/fisiología , Regulación de la Expresión Génica de las Plantas , Técnicas de Silenciamiento del Gen , Chaperonas Moleculares/genética , Fotosíntesis , Plantas Modificadas Genéticamente , Técnicas del Sistema de Dos Híbridos
9.
J Phys Chem A ; 125(11): 2344-2355, 2021 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-33719445

RESUMEN

The triplet-triplet annihilation (TTA) effect of sensitizers themselves can lead to the additional quenching of lifetimes of triplet states; therefore, how to weaken the TTA effect of sensitizers is an urgent issue to be resolved for their further applications. Besides, it remains a tremendous challenge for constructing supramolecular systems of photosensitizers based on photosensitizer-functionalized pillararenes because there have been very few investigations on them. Thus, 2,6-diiodo-1,3,5,7-tetramethyl-8-phenyl-4,4-difluoroboradiazaindacene (DIBDP) and ethoxy pillar[5]arene (EtP5) were utilized to synthesize a DIBDP-functionalized pillar[5]arene (EtP5-DIBDP), a cyano-containing DIBDP (G) used as a guest molecule was also prepared, and they were used to investigate the electron-transfer mechanism between EtP5 and DIBDP moieties and weaken the TTA effect of DIBDP moieties. The theoretical computational results of frontier molecular orbitals and isosurfaces of spin density preliminarily predicted that the cavities of the EtP5 moiety had influence on the fluorescence emission of DIBDP units but not on their triplet states in EtP5-DIBDP. The fluorescence emission intensities in a variety of solvents with different polarities and electrochemical studies revealed that there was electron transfer from EtP5 to the DIBDP units, and the electron-transfer process had influence on the fluorescence emission but not on the triplet states of DIBDP moieties in EtP5-DIBDP, which verified the results of density functional theory calculations. The triplet state lifetimes of EtP5-DIBDP were longer than those of DIBDP and G and the photooxidation abilities of EtP5-DIBDP were better than those of DIBDP and G at a high concentration (1.0 × 10-5 M) in various solvents; in contrast, the intrinsic triplet state lifetimes and singlet oxygen quantum yields (ΦΔ) of DIBDP, G, and EtP5-DIBDP were very similar. This was because the steric hindrance of EtP5 moieties could weaken the TTA effect of DIBDP moieties without influencing their intrinsic triplet state lifetimes in EtP5-DIBDP.

10.
Plant Biotechnol J ; 18(2): 526-539, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31350932

RESUMEN

The biosynthesis of very-long-chain fatty acids (VLCFAs) and their transport are required for fibre development. However, whether other regulatory factors are involved in this process is unknown. We report here that overexpression of an Arabidopsis gene ankyrin repeat-containing protein 2A (AKR2A) in cotton promotes fibre elongation. RNA-Seq analysis was employed to elucidate the mechanisms of AKR2A in regulating cotton fibre development. The VLCFA content and the ratio of VLCFAs to short-chain fatty acids increased in AKR2A transgenic lines. In addition, AKR2A promotes fibre elongation by regulating ethylene and synergizing with the accumulation of auxin and hydrogen peroxide. Analysis of RNA-Seq data indicates that AKR2A up-regulates transcript levels of genes involved in VLCFAs' biosynthesis, ethylene biosynthesis, auxin and hydrogen peroxide signalling, cell wall and cytoskeletal organization. Furthermore, AKR2A interacted with KCS1 in Arabidopsis both in vitro and in vivo. Moreover, the VLCFA content and the ratio of VLCFAs to short-chain fatty acids increased significantly in seeds of AKR2A-overexpressing lines and AKR2A/KCS1 co-overexpressing lines, while AKR2A mutants are the opposite trend. Our results uncover a novel cotton fibre growth mechanism by which the critical regulator AKR2A promotes fibre development via activating hormone signalling cascade by mediating VLCFA biosynthesis. This study provides a potential candidate gene for improving fibre yield and quality through genetic engineering.


Asunto(s)
Fibra de Algodón , Ácidos Grasos , Gossypium , Arabidopsis/genética , Ácidos Grasos/biosíntesis , Ácidos Grasos/genética , Regulación de la Expresión Génica de las Plantas/genética , Gossypium/genética , Gossypium/metabolismo , Chaperonas Moleculares/metabolismo , Transducción de Señal/genética
11.
Chemistry ; 26(16): 3591-3599, 2020 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-31916322

RESUMEN

Intersystem crossing (ISC) was observed for naphthalimide (NI)-derived Tröger's base, and the ISC was confirmed to occur by a spin-orbital charge-transfer (SOCT) mechanism. Conventional electron donor/acceptor dyads showing SOCT-ISC have semirigid linkers. In contrast, the linker between the two chromophores in Tröger's base is rigid and torsion is completely inhibited, which is beneficial for efficient SOCT-ISC. Femtosecond transient absorption (TA) spectra demonstrated charge-separation and charge-recombination-induced ISC processes. Nanosecond TA spectroscopy confirmed the ISC, and the triplet state is long-lived (46 µs, room temperature). The ISC quantum yield is dependent on solvent polarity (8-41 %). The triplet state was studied by pulsed-laser-excited time-resolved EPR spectroscopy, and both the NI-localized triplet state and triplet charge-transfer state were observed, which is in good agreement with the spin-density analysis. The Tröger's base was confirmed to be a potent photodynamic therapy reagent with HeLa cells (EC50 =5.0 nm).


Asunto(s)
1-Naftilamina/análogos & derivados , Naftalimidas/química , Fotoquimioterapia , Quinolonas/química , Solventes/química , 1-Naftilamina/química , Espectroscopía de Resonancia por Spin del Electrón , Células HeLa , Humanos
12.
Inorg Chem ; 59(20): 14731-14745, 2020 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-32864961

RESUMEN

Two anthryl platinum(II) N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-benzenediamine Schiff base complexes were synthesized, with the anthryl attached via its 9 position (Pt-9An) or 2 position (Pt-2An) to the platinum (Pt) Schiff base backbone. The complexes show unusually small Stokes shifts (0.23 eV), representing a very small energy loss for the photoexcitation/intersystem crossing process, which is beneficial for applications as triplet photosensitizers. Phosphorescence of the Pt(II) coordination framework (ΦP = 11.0%) is quenched in the anthryl-containing complexes (ΦP = 4.0%) and shows a biexponential decay (τP = 3.4 µs/87% and 18.2 µs/13%) compared to the single-exponential decay of the native Pt(II) Schiff base complex (τP = 3.7 µs). Femtosecond/nanosecond transient absorption spectroscopy suggests an equilibrium between triplet anthracene (3An) and triplet metal-to-ligand charge-transfer (3MLCT) states, with the dark 3An state slightly lower in energy (1.96 eV for Pt-9An and 1.90 eV for Pt-2An) than the emissive 3MLCT state (1.97 eV for Pt-9An and 1.91 eV for Pt-2An). Intramolecular triplet-triplet energy transfer (TTET) and reverse TTET take 4.8 ps/444 ps for Pt-9An and 55 ps/1.7 ns for Pt-2An, respectively. The triplet-state equilibrium extends the triplet-state lifetime of the complexes to 103 µs (Pt-2An) or 163 µs (Pt-9An), in comparison to the native Pt(II) complex, which shows a lifetime of 4.0 µs. The complexes were used for triplet-triplet-annihilation upconversion with perylene as the triplet acceptor. The upconversion quantum yield is up to 15%, and a large anti-Stokes shift (0.75 eV) is achieved by excitation into the singlet metal-to-ligand charge-transfer absorption band (589 nm) of the complexes (anti-Stokes shift is 0.92 eV with 9,10-diphenylanthracene as the acceptor).

13.
J Phys Chem A ; 124(45): 9360-9374, 2020 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-33140645

RESUMEN

The spin-orbit charge transfer intersystem crossing (SOCT-ISC) and the formation of a long-lived charge transfer (CT) state were studied with a series of 4,4'-dimethoxy triphenylamine-BODIPY compact electron donor/acceptor dyads. Different torsion freedoms were applied in the dyads to tune the electronic coupling between the donor and acceptor, and a red-shifted CT absorption band was observed for one dyad. The dyads show solvent polarity-dependent singlet oxygen photosensitizing ability (quantum yields 3%-79%). Nanosecond transient absorption spectra of the dyad in nonpolar solvent confirm the formation of triplet states. The intrinsic triplet state lifetime is up to 383 µs (in fluid solution), which is much longer than that accessed with the heavy atom effect (276 µs). Intermolecular triplet photosensitizing of the dyads in a polar solvent produces a long-lived 3CT state (lifetime, τCT = 8.0 µs supported by the electron spin density surface analysis). The triplet state lifetime of the dyads doped in a Clear Flex 50 polymer film is exceptionally long (7.6-11.4 ms), and formation of a long-lived CT state (37 µs) was observed. Triplet-triplet annihilation upconversion was performed with the electron donor/acceptor dyads used as the triplet photosensitizer and perylene used as the triplet acceptor; the upconversion quantum yield is up to 15.8%.

14.
J Chem Phys ; 153(22): 224304, 2020 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-33317285

RESUMEN

We prepared a series of compact Bodipy-anthryl electron donor/acceptor triads and dyads by attaching anthryl moieties at the 3-,5-positions of the Bodipy core, with a novel conformation restriction approach, to study the spin-orbit charge transfer intersystem crossing (SOCT-ISC). The conformation restrictions are imposed by the BF2 unit of Bodipy without invoking the previously reported method with 1,7-dimethyl or 1,3-dimethyl groups. Our new approach shows a few advantages, including the stronger electron accepting ability of the methyl-free Bodipy core (reduction potential anodically shifted by +0.3 V vs the methylated Bodipy), red-shifted absorption (by 21 nm), and longer triplet state lifetime (372 µs vs 126 µs). The effects of the different mutual orientations of the electron donor and acceptor on ultraviolet-visible absorption, fluorescence, triplet state quantum yields, and lifetimes were studied. Triads with orthogonal geometries show higher singlet oxygen quantum yields (ΦΔ = 37%) than those with more coplanar geometries. Since the non-radiative decay for the S1 state is significant in the parent Bodipy chromophore (ΦF = 6.0%), we propose that in dyads/triads, the charge separation and recombination-induced ISC outcompete the non-radiative decay to the ground state, which is new in the study of SOCT-ISC. Density functional theory computation indicated a shallow torsion potential energy curve as compared to the meso-anthryl-Bodipy dyad analog, which may contribute a low triplet state quantum yield of the new dyads/triads. Triplet-triplet annihilation upconversion was performed with the electron donor/acceptor dyads as the triplet photosensitizer, with an upconversion quantum yield of 12.3%.

15.
J Chem Phys ; 153(18): 184312, 2020 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-33187415

RESUMEN

A perylene (Pery)-phenoxazine (PXZ) compact orthogonal electron donor/acceptor dyad was prepared to study the relationship between the molecular structures and the spin-orbit charge transfer intersystem crossing (SOCT-ISC), as well as the electron spin selectivity of the ISC process. The geometry of Pery-PXZ (80.0°) is different from the previously reported perylene-phenothiazine dyad (Pery-PTZ, 91.5°), although there is only one atom variation for the two dyads. Pery-PXZ shows a high singlet oxygen quantum yield (84%). Femtosecond transient absorption spectra indicate that the charge separation (CS, faster than 120 fs) is faster than the Pery-PTZ analog (CS, 250 fs) and charge recombination (CR, i.e., SOCT-ISC, 5.98 ns) of Pery-PXZ is slower than the Pery-PTZ analog (CR, 0.9 ns). The intrinsic triplet state lifetime of Pery-PXZ is 242 µs vs the lifetime of 181 µs for the Pery-PTZ analog. Moreover, the triplet state lifetime of Pery-PXZ in the solid polymer matrix is extended to 4.45 ms, which indicates that the triplet state of Pery-PXZ in fluid solution is deactivated not only by the triplet-triplet annihilation effect but also by other factors such as vibration coupled relaxation. Interestingly, with pulsed laser excited time-resolved electron paramagnetic resonance spectroscopy, the electron spin polarization (ESP) pattern of the triplet state of the current dyad is opposite to that of Pery-PTZ. These results demonstrated the rich electron spin chemistry of the ISC of compact electron donor/acceptor dyads, e.g., the ESP is dependent on not only the molecular geometry but also the structure of the electron donor (or acceptor).

16.
J Chem Phys ; 152(11): 114701, 2020 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-32199436

RESUMEN

In order to study the spin-orbit charge transfer induced intersystem crossing (SOCT-ISC), Bodipy (BDP)-carbazole (Cz) compact electron donor/acceptor dyads were prepared. Charge transfer (CT) emission bands were observed for dyads showing strong electronic coupling between the donor and the acceptor (coupling matrix elements VDA, 0.06 eV-0.18 eV). Depending on the coupling magnitude, the CT state of the dyads can be either dark or emissive. Equilibrium between the 1LE (locally excited) state and the 1CT state was confirmed by temperature-dependent fluorescence studies. Efficient ISC was observed for the dyads with Cz connected at the meso-position of the BDP. Interestingly, the dyad with non-orthogonal geometry shows the highest ISC efficiency (ΦΔ = 58%), which is different from the previous conclusion. The photo-induced charge separation (CS, time constant: 0.7 ps) and charge recombination (CR, ∼3.9 ns) were studied by femtosecond transient absorption spectroscopy. Nanosecond transient absorption spectroscopy indicated that the BDP-localized triplet state was exceptionally long-lived (602 µs). Using pulsed laser excited time-resolved electron paramagnetic resonance spectroscopy, the SOCT-ISC mechanism was confirmed, and we show that the electron spin polarization of the triplet state is highly dependent on the mutual orientation of the donor and acceptor. The dyads were used as triplet photosensitizers for triplet-triplet-annihilation (TTA) upconversion, and the quantum yield is up to 6.7%. TTA-based delayed fluorescence was observed for the dyads (τDF = 41.5 µs). The dyads were also used as potent photodynamic therapy reagents (light toxicity of IC50 = 0.1 µM and dark toxicity of IC50 = 70.8 µM).

17.
Chemistry ; 24(34): 8577-8588, 2018 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-29668061

RESUMEN

A series of substituted 2-phenylquinoxaline ligands have been explored to finely tune the visible emission properties of a corresponding set of cationic, cyclometallated iridium(III) complexes. The electronic and redox properties of the complexes were investigated through experimental (including time-resolved luminescence and transient absorption spectroscopy) and theoretical methods. The complexes display absorption and phosphorescent emissions in the visible region that are attributed to metal to ligand charge-transfer transitions. The different substitution patterns of the ligands induce variations in these parameters. Time-dependent DFT studies support these assignments and show that there is likely to be a strong spin-forbidden contribution to the visible absorption bands at λ=500-600 nm. Calculations also reliably predict the magnitude and trends in triplet emitting wavelengths for the series of complexes. The complexes were assessed as potential sensitisers in triplet-triplet annihilation upconversion experiments by using 9,10-diphenylanthracene as the acceptor; the methylated variants performed especially well with impressive upconversion quantum yields of up to 39.3 %.

18.
Org Biomol Chem ; 16(20): 3692-3701, 2018 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-29693683

RESUMEN

In this review, recent progress in heavy atom-free triplet photosensitizers was summarized. The general approaches include attaining S1/Tn states sharing similar energy levels or proper molecular geometry to satisfy the angular momentum reservation in intersystem crossing (ISC). ISC via the higher singlet excited state (Sn, n > 1) → Tm (m > 1), which is a rarely reported phenomenon, was also discussed. The ISC of some Bodipy dimers was proposed to be via the 'doubly excited state', but recent studies show that the ISC mechanism of these Bodipy dimers is charge separation/recombination. These new findings in the study of triplet photosensitizers are useful for photovoltaics, photodynamic therapy and photocatalysis, as well as in fundamental photochemistry studies.

19.
Chemistry ; 23(54): 13465-13473, 2017 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-28695636

RESUMEN

A series of hybrid luminescent porous polymers (HLPPs) are synthesized through Friedel-Crafts reactions by tuning the molar ratio of triphenylamine (TPA) to octavinylsilsesquioxane (OVS). The synthesized HLPPs exhibit high Brunauer-Emmett-Teller surface areas up to 841±10 m2 g-1 , high thermal stability with decomposition temperatures (Td at 5 wt %) up to 440 °C in air, and strong blue-violet luminescence at approximately 450 nm. The porosities and luminescent properties of the HLPPs, including emission wavelength, intensity, fluorescence quantum yield, and monochromaticity, can be tuned easily by modulating the molar ratio of TPA to OVS. In addition, the polymers may serve as excellent fluorescent probes for multianalyte detection, with high fluorescence quenching coefficients (KSV ) of 8900 and 4400 m-1 for Fe3+ and Cu2+ , respectively.

20.
Food Chem ; 440: 138203, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38104452

RESUMEN

Whole grains have garnered significant attention in the food industry due to their retained abundant nutrients when compared to refined grains. However, limited knowledge exists regarding the digestive behavior of starch and protein. This study compared the physicochemical properties and in vitro starch and protein digestibility of cooked whole wheat flour (WF) and naked oat flour (NOF), and evaluated the impact of endogenous components (protein, lipid, ß-glucan, and polyphenol) on the physicochemical properties and digestibility of WF and NOF. The result indicated that the final hydrolysis rate of WF samples (starch: 23.2 %∼46.3 %; protein: 23.1 %∼63.0 %) was lower than that of NOF samples (starch: 32.1 %∼61.0 %; protein: 32.3 %∼63.6 %). The removal of different endogenous components led to improved digestibility of starch and protein in both WF and NOF. This study contributes to the understanding of the starch and protein digestibility of whole grains, consequently facilitating the development of whole grain products.


Asunto(s)
Harina , Almidón , Almidón/química , Triticum/metabolismo , Avena/química , Proteínas
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