RESUMO
Single lanthanide (Ln) ion doped upconversion nanoparticles (UCNPs) exhibit great potential for biomolecule sensing and counting. Plasmonic structures can improve the emission efficiency of single UCNPs by modulating the energy transferring process. Yet, achieving robust and large-area single UCNP emission modulation remains a challenge, which obstructs investigation and application of single UCNPs. Here, we present a strategy using metal nanohole arrays (NHAs) to achieve energy-transfer modulation on single UCNPs simultaneously within large-area plasmonic structures. By coupling surface plasmon polaritons (SPPs) with higher-intermediate state (1D2 â 3F3, 1D2 â 3H4) transitions, we achieved a remarkable up to 10-fold enhancement in 800 nm emission, surpassing the conventional approach of coupling SPPs with an intermediate ground state (3H4 â 3H6). We numerically simulate the electrical field distribution and reveal that luminescent enhancement is robust and insensitive to the exact location of particles. It is anticipated that the strategy provides a platform for widely exploring applications in single-particle quantitative biosensing.
RESUMO
Self-assembling peptides represent a captivating area of study in nanotechnology and biomaterials. This interest is largely driven by their unique properties and the vast application potential across various fields such as catalytic functions. However, design complexities, including high-dimensional sequence space and structural diversity, pose significant challenges in the study of such systems. In this work, we explored the possibility of self-assembled peptides to catalyze the hydrolysis of hydrosilane for hydrogen production using ab initio calculations and carried out wet-lab experiments to confirm the feasibility of these catalytic reactions under ambient conditions. Further, we delved into the nuanced interplay between sequence, structural conformation, and catalytic activity by combining modeling with experimental techniques such as transmission electron microscopy and nuclear magnetic resonance and proposed a dual mode of the microstructure of the catalytic center. Our results reveal that although research in this area is still at an early stage, the development of self-assembled peptide catalysts for hydrogen production has the potential to provide a more sustainable and efficient alternative to conventional hydrogen production methods. In addition, this work also demonstrates that a computation-driven rational design supplemented by experimental validation is an effective protocol for conducting research on functional self-assembled peptides.
Assuntos
Hidrogênio , Peptídeos , Hidrogênio/química , Catálise , Peptídeos/química , Modelos Moleculares , HidróliseRESUMO
The acoustic coding metasurfaces (ACMs) have the ability to manipulate complex acoustic behavior by reconstructing the coding sequence. In particular, the design of broadband coding enhances the versatility of ACMs. ACMs offer significant advantages over traditional metasurfaces, including a limited number of units and flexible wave control performance. The unit quantity is determined by 2n, with 1-bit utilizing 2 units, 2-bit using 4 units, and 3-bit employing 8 units. Utilizing multiple bits allows for precise control over the phase of sound waves and enables the realization of more intricate acoustic functions. To address the requirements of broadband multi-bit applications, this paper presents the development of novel 3-bit broadband reflected acoustic coding metasurfaces (BACMs) with eight coding units. These metasurfaces are systematically designed using the bottom-up topology optimization method. A constant phase difference of 45° can be achieved across all eight coding units within a broad frequency range. Additionally, the spiral distribution of phase differences enables the construction of an acoustic vortex metasurface. Moreover, by combining the convolution method, the strategies are outlined for constructing vortex-focusing metasurfaces and vortex beam manipulation metasurfaces. These 3-bit coding metasurfaces possess significant potential in the fields of acoustic particle suspension and acoustic communication.
RESUMO
Heading date is one of the important agronomic traits that affects rice yield. In this study, we cloned a new rice B3 family gene, OsL1, which regulates rice heading date. Importantly, osl1-1 and osl1-2, two different types of mutants of OsL1 were created using the gene editing technology CRISPR/Cas9 system and exhibited 4 days earlier heading date than that of the wild type under short-day conditions. Subsequently, the plants overexpressing OsL1, OE-OsL1, showed a 2-day later heading date than the wild type in Changsha and a 5-day later heading date in Lingshui, but there was no significant difference in other yield traits. Moreover, the results of subcellular localization study indicated that OsL1 protein was located in the nucleus and the expression pattern analysis showed that OsL1 gene was expressed in rice roots, stems, leaves, and panicles, and the expression level was higher at the root and weak green panicle. In addition, the OsL1 gene was mainly expressed at night time under short-light conditions. The transcriptomic analysis indicated that OsL1 might be involved in the Hd1-Hd3a pathway function. Together, our results revealed that the cloning and functional analysis of OsL1 can provide new strategy for molecular design breeding of rice with suitable fertility period. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01444-1.
RESUMO
BACKGROUND: Hyperlipidemia damages vascular wall and serves as a foundation for diseases such as atherosclerosis, hypertension and stiffness. The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is implicated in vascular dysfunction associated with hyperlipidemia-induced vascular injury. Sodium tanshinone IIA sulfonate (STS), a well-established cardiovascular protective drug with recognized anti-inflammatory, antioxidant, and vasodilatory properties, is yet to be thoroughly investigated for its impact on vascular relaxant imbalance induced by hyperlipidemia. METHODS: In this study, we treated ApoE-knockout (ApoE-/-) mouse with STS and assessed the activation of the NLRP3 inflammasome, expression of MMP2/9, integrity of elastic fibers, and vascular constriction and relaxation. RESULTS: Our findings reveal that STS intervention effectively preserves elastic fibers, significantly restores aortic relaxation function in ApoE-/- mice, and reduces their excessive constriction. Furthermore, STS inhibits the phosphorylation of spleen tyrosine kinase (SYK), suppresses NLRP3 inflammasome activation, and reduces MMP2/9 expression. CONCLUSIONS: These results demonstrate that STS protects vascular relaxation against hyperlipidemia-induced damage through modulation of the SYK-NLRP3 inflammasome-MMP2/9 pathway. This research provides novel insights into the mechanisms underlying vascular relaxation impairment in a hyperlipidemic environment and uncovers a unique mechanism by which STS preserves vascular relaxation, offering valuable foundational research evidence for its clinical application in promoting vascular health.
Assuntos
Modelos Animais de Doenças , Inflamassomos , Metaloproteinase 2 da Matriz , Metaloproteinase 9 da Matriz , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Proteína 3 que Contém Domínio de Pirina da Família NLR , Fenantrenos , Transdução de Sinais , Quinase Syk , Vasodilatação , Animais , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Inflamassomos/metabolismo , Quinase Syk/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Fenantrenos/farmacologia , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Vasodilatação/efeitos dos fármacos , Hiperlipidemias/tratamento farmacológico , Hiperlipidemias/fisiopatologia , Vasodilatadores/farmacologia , Fosforilação , Camundongos , Aorta/efeitos dos fármacos , Aorta/fisiopatologia , Aorta/metabolismo , Aorta/enzimologia , Apolipoproteínas ERESUMO
BACKGROUND AND STUDY AIM: To assess the efficacy and safety of a fibrin sealant for the prevention of leak resulting from mucosal penetration at the esophagus or cardia during a STER procedure to remove gastrointestinal submucosal tumors (SMTs). PATIENTS AND METHODS: Between April 2014 and October 2022, a total of 290 patients with oesophageal or cardiac SMTs underwent STER at our centre. We retrospectively identified patients with oesophageal or cardia SMTs who underwent STER and experienced mucosal penetration of the cardia or oesophagus during the procedure. A total of 31 mucosal penetrations in 30 procedures were included. Of the 31 mucosal penetrations, 12 occurred in the cardia, and the other 19 occurred in the oesophagus. All 31 sites received the fibrin sealant to close the mucosal penetration. Clinical characteristics, procedure-related parameters, detailed data of the mucosal penetrations, and treatment outcomes using the fibrin sealant were reviewed for all 30 patients to assess the efficacy and safety of the fibrin sealant for closure of mucosal penetration at the cardia or oesophagus. RESULTS: For the 31 mucosal penetrations, the mean size was 0.08 ± 0.06 cm2 (range 0.01-0.25 cm2). Mucosal closure using the fibrin sealant was performed successfully in all 31 mucosal penetrations. Of the 31 mucosal penetrations, clips were used in 13 cases. All 30 patients were discharged after a median of 7 days (range 4-20 day) postoperatively. During a mean 62 months (range 6-107 months) follow-up, all 31 mucosal penetrations successfully healed without the occurrence of infection, ulcer, oesophagitis, chest infection or abdominal infection. CONCLUSION: For the closure of mucosal penetration during STER at the cardia or oesophagus, a fibrin sealant is both safe and efficacious. It is necessary to conduct more research on the viability, effectiveness, and safety of using a fibrin sealant to close wider mucosal penetrations.
Assuntos
Ressecção Endoscópica de Mucosa , Neoplasias Esofágicas , Neoplasias Gastrointestinais , Neoplasias Gástricas , Humanos , Cárdia/cirurgia , Cárdia/patologia , Adesivo Tecidual de Fibrina/uso terapêutico , Ressecção Endoscópica de Mucosa/métodos , Neoplasias Gástricas/cirurgia , Neoplasias Gástricas/patologia , Estudos Retrospectivos , Esôfago/patologia , Neoplasias Gastrointestinais/patologia , Resultado do Tratamento , Mucosa Gástrica/cirurgia , Mucosa Gástrica/patologia , Neoplasias Esofágicas/cirurgia , Neoplasias Esofágicas/patologiaRESUMO
BACKGROUND: A major risk factor for neurodegenerative disorders is old age. Nutritional interventions that delay aging, such as calorie restriction (CR) and intermittent fasting (IF), as well as pharmaceuticals that affect the pathways linking nutrition and aging processes, have been developed in recent decades and have been shown to alleviate the effects of aging on the brain. SUMMARY: CR is accomplished by alternating periods of ad libitum feeding and fasting. In animal models, IF has been shown to increase lifespan and slow the progression and severity of age-related pathologies such as cardiovascular and neurodegenerative diseases and cancer. According to recent research, dietary changes can help older people with dementia retain brain function. However, the mechanisms underlying the neuroprotective effect of IF on the aging brain and related questions in this area of study (i.e., the potential of IF to treat neurodegenerative disorders) remain to be examined. KEY MESSAGES: This review addresses the hypothesis that IF may have translational potential in protecting the aged brain while summarizing the research supporting the putative neuroprotective mechanisms of IF in animal models. Additionally, given the emerging understanding of the connection between aging and dementia, our investigations may offer a fresh perspective on the use of dietary interventions for enhancing brain function and preventing dementia in elderly individuals. Finally, the absence of guidelines regarding the application of IF in patients hampers its broad utilization in clinical practice, and further studies are needed to improve our knowledge of the long-term effects of IF on dementia before it can be widely prescribed. In conclusion, IF may be an ancillary intervention for preserving memory and cognition in elderly individuals.
Assuntos
Envelhecimento , Encéfalo , Restrição Calórica , Jejum Intermitente , Animais , Humanos , Envelhecimento/fisiologia , Encéfalo/fisiologia , Jejum Intermitente/fisiologia , Doenças Neurodegenerativas/prevenção & controle , Neuroproteção/fisiologiaRESUMO
This study aimed to explore the pharmacodynamics and mechanisms of different processing methods of Ligustrum lucidum Ait. (LLA) in addressing kidney-yin deficiency (KYD). Forty-eight Sprague-Dawley rats were divided into eight groups based on their weight. The KYD model was established by intragastric administration of levothyroxine sodium. Each group was administered the corresponding treatment for 15 consecutive days. The general condition of the rats during the treatment period was observed. In addition, the levels of cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), and the ratio of cAMP to cGMP in the serum of rats from different groups were measured. Serum samples were analyzed using the ultra-performance liquid chromatography (UPLC)-Orbitrap Fusion MS technique for metabolomics analysis. Compared with the model group, the general condition of the rats in the wine-steamed L. lucidum group (WL) and salt-steamed L. lucidum group (SSL) groups showed significant improvement. The serum levels of cAMP, cGMP, and the cAMP-to-cGMP ratio tended to return to normal. Metabolic analysis identified 38 relevant biomarkers and revealed 3 major metabolic pathways: phenylalanine, tyrosine, and tryptophan biosynthesis; phenylalanine metabolism; and sphingolipid metabolism. The different processing methods of LLA demonstrated therapeutic effects on KYD in rats, likely related to the restoration of disturbed metabolism by adjusting the levels of endogenous metabolites in the kidney. The SSL demonstrated significantly superior effects compared with the other four types of LLA processed products.
RESUMO
BACKGROUNDS: Short-term exposure to air pollutants increases the risk of migraine, but the long-term impacts of exposure to multiple pollutants on migraine have not been established. The aim of this large prospective cohort study was to explore these links. METHODS: A total of 458,664 participants who were free of migraine at baseline from the UK Biobank were studied. Cox proportional hazards models were used to estimate the risk of new-onset migraine from combined long-term exposure to four pollutants, quantified as an air pollution score using principal component analysis. RESULTS: During a median (IQR) follow-up of 12.5 (11.8, 13.2) years, a total of 5417 new-onset migraine cases were documented. Long-term exposure to multiple air pollutants was associated with an increased risk of new-onset migraine, as indicated by an increased in the SDs of PM2.5 (hazard ratio (HR): 1.04, 95% CI: 1.01-1.06, P = 0.009), PM10 (HR: 1.07, 95% CI: 1.04-1.10, P < 0.001), NO2 (HR: 1.10, 95% CI: 1.07-1.13, P < 0.001) and NOx (HR: 1.04, 95% CI: 1.01-1.07, P = 0.005) in the main model. The air pollution score showed a doseresponse association with an increased risk of new-onset migraine. Similarly, compared with those of the lowest tertile, the HRs (95% CI) of new-onset migraine were 1.11 (95% CI: 1.04-1.19, P = 0.002) and 1.17 (95% CI: 1.09-1.26, P < 0.001) in tertiles 2 and 3, respectively, according to the main model (P trend < 0.001). CONCLUSION: Long-term individual and joint exposure to multiple air pollutants is associated with an increased risk of new-onset migraine.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Humanos , Poluentes Atmosféricos/análise , Material Particulado/toxicidade , Estudos Prospectivos , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Poluição do Ar/efeitos adversos , Dióxido de NitrogênioRESUMO
PURPOSE: Male cancer survivors experience confusion about fertility following cancer treatment. The aims of this study were to evaluate survivors' semen quality in different tumor type groups in China and to analyze the current situation and challenges of male cancer patients with sperm cryopreservation. METHODS: This was a multicenter retrospective study of male patients with cancer who underwent sperm cryopreservation in 16 regions of the national sperm banks over an 11-year period from 2010 to 2020. RESULTS: The number of male cancer patients with sperm cryopreservation showed an overall upward trend. The development of male cancer fertility preservation (FP) in the eastern, central, and western regions of Chinese displayed imbalance. There are seven tumor types for sperm preservation in the top incidence ten tumor types, including lymphoma, leukemia, nasopharyngeal carcinoma, sarcoma, thyroid cancer, and brain tumor. Moreover, nasopharyngeal carcinoma is a high incidence rate in China, which is related to high sperm preservation rate, different from other countries. The most percentage of males receiving sperm cryopreservation in the testicular cancers (15-39 years old) of China in 2020 was 5.55%, 1.29% in the lymphoma, and 0.39% in the leukemia. According to the type of cancer, a statistically significant lower pre-sperm density, total sperm output, and post-sperm density was observed in testicular cancers. It is worth noting that the prevalence of azoospermia 22.2% in leukemia patients attribute to urgent treatment before sperm cryopreservation. Disposition of cryopreserved sperm categories included continued storage (47.2%), discarded (9%), death (0.9%), and use (3.7%). CONCLUSION: This study provides the first comprehensive national statistical census and review of fertility preservation in male cancer patients with respect to trends, prevalence, and cancer types. The development of male cancer fertility preservation in China is imbalanced and percentage of males receiving sperm cryopreservation in the adolescent and young adult cancers was low. Sixteen human sperm banks from China analyze current problems and challenges, and then prioritize steps toward the achievement of the FP strategy framework for Healthy China 2030.
Assuntos
Criopreservação , Preservação da Fertilidade , Neoplasias , Preservação do Sêmen , Bancos de Esperma , Humanos , Masculino , Preservação da Fertilidade/métodos , China/epidemiologia , Criopreservação/métodos , Adulto , Preservação do Sêmen/métodos , Neoplasias/epidemiologia , Neoplasias/patologia , Adolescente , Espermatozoides , Estudos Retrospectivos , Análise do Sêmen , Infertilidade Masculina/epidemiologia , Adulto Jovem , População do Leste AsiáticoRESUMO
Three new C10 and C12 aliphatic δ-lactones (1-3), three new fatty acid methyl esters (4-6), and eight known compounds (7-14) were isolated from the marine Aureobasidium sp. LUO5. Their structures were established by detailed analyses of the NMR, HRESIMS, optical rotation, and ECD data. All isolates were tested for their inhibitory effects on nitric oxide production in LPS-induced BV-2 cells. Notably, compound 4 displayed the strongest inhibitory effect with the IC50 value of 120.3â nM.
Assuntos
Aureobasidium , Óxido Nítrico , Animais , Camundongos , Aureobasidium/química , Aureobasidium/metabolismo , Linhagem Celular , Lipopolissacarídeos/antagonistas & inibidores , Lipopolissacarídeos/farmacologia , Conformação Molecular , Estrutura Molecular , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/biossíntese , Óxido Nítrico/metabolismo , LactonasRESUMO
The beamwidth is a primary directivity metric for the design of a constant directivity horn. To date, investigations on this property have predominantly been restricted to the half-space radiation or idealized geometries. This paper examines the beamwidth behavior of an axisymmetric horn mounted in a finite cylindrical enclosure by proposing an elegant multimodal solution to the far-field directivity pattern. The variation of beamwidth is examined for the frequency, dimensions of the enclosure, and shape of the horn. At low frequencies, a fitted model is proposed to precisely depict the intrinsic beam narrowing governed by the enclosure diffraction. The asymptotic behavior of the beamwidth is explored as the flange width increases. In the high-frequency range, the horn profile is a determinant of the directivity characteristics. We report the possibility of extending the bandwidth of a constant directivity horn by leveraging the enclosure diffraction effects. The proposed analytical method is highly accurate and much faster than the finite element method for wideband analysis. It allows for an arbitrary velocity distribution at the mouth of the horn and incorporates idealized flange configurations such as an infinite baffle, a zero-thickness closed baffle, and an infinitely long enclosure as limit cases.
RESUMO
Salinity is one of the most serious threats to sustainable agriculture. The Salt Overly Sensitive (SOS) signaling pathway plays an important role in salinity tolerance in plants, and the SOS2 gene plays a critical role in this pathway. Mulberry not only has important economic value but also is an important ecological tree species; however, the roles of the SOS2 gene associated with salt stress have not been reported in mulberry. To gain insight into the response of mulberry to salt stress, SOS2 (designated MulSOS2) was cloned from mulberry (Morus atropurpurea Roxb), and sequence analysis of the amino acids of MulSOS2 showed that it shares some conserved domains with its homologs from other plant species. Our data showed that the MulSOS2 gene was expressed at different levels in different tissues of mulberry, and its expression was induced substantially not only by NaCl but also by ABA. In addition, MulSOS2 was exogenously expressed in Arabidopsis, and the results showed that under salt stress, transgenic MulSOS2 plants accumulated more proline and less malondialdehyde than the wild-type plants and exhibited increased tolerance to salt stress. Moreover, the MulSOS2 gene was transiently overexpressed in mulberry leaves and stably overexpressed in the hairy roots, and similar results were obtained for resistance to salt stress in transgenic mulberry plants. Taken together, the results of this study are helpful to further explore the function of the MulSOS2 gene, which provides a valuable gene for the genetic breeding of salt tolerance in mulberry.
Assuntos
Arabidopsis , Morus , Tolerância ao Sal/genética , Morus/genética , Melhoramento Vegetal , Estresse Salino , Agricultura , Plantas Geneticamente ModificadasRESUMO
Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu-NSO4/CN, with highly dispersed Cu(II)-SO4 sites has been reported, in which CO2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (-0.5â V vs. RHE, FEformate=87.4 %). Pure HCOOH is produced with an energy conversion efficiency of 44.3 % at a cell voltage of 2.8â V. Theoretical modeling demonstrates that sulfate promotes CO2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production.
RESUMO
The fifth-generation (5G) mobile cellular network is vulnerable to various security threats. Radio frequency fingerprint (RFF) identification is an emerging physical layer authentication technique which can be used to detect spoofing and distributed denial of service attacks. In this paper, the performance of RFF identification is studied for 5G mobile phones. The differential constellation trace figure (DCTF) is extracted from the physical random access channel (PRACH) preamble. When the database of all 64 PRACH preambles is available at the gNodeB (gNB), an index-based DCTF identification scheme is proposed, and the classification accuracy reaches 92.78% with a signal-to-noise ratio of 25 dB. Moreover, due to the randomness in the selection of preamble sequences in the random access procedure, when only a portion of the preamble sequences can be trained, a group-based DCTF identification scheme is proposed. The preamble sequences generated from the same root value are grouped together, and the untrained sequences can be identified based on the trained sequences within the same group. The classification accuracy of the group-based scheme is 89.59%. An experimental system has been set up using six 5G mobile phones of three models. The 5G gNB is implemented on the OpenAirInterface platform.
RESUMO
Purpose: We aimed to characterize physical activity (PA) trajectories across adulthood and to estimate their association with incident hypertension risk. Methods: Data were obtained from the China Health and Nutrition Survey (CHNS) conducted during 2004-2011. Group-based trajectory modeling (GBTM) was used to identify distinct groups of PA trajectories. The Cox proportional hazards model was used to investigate the association. Results: A total of 11,162 participants whose PA was repeatedly estimated by self-report from questionnaires two to four times in the CHNS were included in our study. During the 5.4 years of follow-up, 3824 incident hypertension cases were identified. Five distinct PA trajectories were identified in men: light and slight decline, light and gradual decline then sharp rise, light to medium-heavy then decline, medium-heavy and gradual decline, and heavy and sharp decline. Two distinct PA trajectories were identified in women: light and stable, and medium and gradual decline. The PA trajectory of medium-heavy and gradual decline was significantly associated with decreased risk of hypertension in men, with the hazard ratios and 95% confidence intervals (CI) being 0.80 (0.63, 0.99), 0.74 (0.59, 0.93), 0.76 (0.60, 0.96), and 0.70 (0.55, 0.88) in models 1-4, respectively. Conclusions: Our study identified five distinct long-term PA trajectories in men and two distinct trajectories in women. The PA trajectory of medium-heavy PA in early adulthood followed by gradual decline was found to be significantly associated with a decreased risk of hypertension in later life in men.
RESUMO
Intracerebral hemorrhagic stroke, characterized by acute hemorrhage in the brain, has a significant clinical prevalence and poses a substantial threat to individuals' well-being and productivity. Recent research has elucidated the role of gut microorganisms and their metabolites in influencing brain function through the microbiota-gut-brain axis (MGBA). This article provides a comprehensive review of the current literature on the common metabolites, short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), produced by gut microbiota. These metabolites have demonstrated the potential to traverse the blood-brain barrier (BBB) and directly impact brain tissue. Additionally, these compounds have the potential to modulate the parasympathetic nervous system, thereby facilitating the release of pertinent substances, impeding the buildup of inflammatory agents within the brain, and manifesting anti-inflammatory properties. Furthermore, this scholarly analysis delves into the existing dearth of investigations concerning the influence of gut microorganisms and their metabolites on cerebral functions, while also highlighting prospective avenues for future research.
RESUMO
CONTEXT: Inspired by the excellent potential application prospects from the precisely controlled attributes displayed by fluorine-substituted-bis(salicylidene)-1,5-diaminonaphthalene (F-BSD) and its derivatives in the domains of photochemistry and photophysics, our present undertaking predominantly focuses on exploring the complexities of photo-induced excited state reactions for F-BSD fluorophores dissolved in solvents with diverse levels of polarity. Our simulations reveal that the excited state intramolecular double proton transfer (ESIDPT) reaction for F-BSD chemosensor can be significantly regulated by solvent polarity-dependent hydrogen bonding interactions and charge recombination induced by photoexcitation, which result from variations in geometries and vertical excitation charge reorganizations. By constructing potential energy surfaces (PESs), we also demonstrate that the stepwise ESIDPT reaction of F-BSD occurs with alternative dual intramolecular hydrogen bonds (O1-H2···N3 or O4-H5···N6). Interestingly, we affirm polar solvents should be conducive to the first-step of ESIDPT process, while nonpolar solvents are in favor of the second step. We sincerely hope solvent polarity-dependent ESIDPT behavior will pave the way for future design of novel luminescent materials. METHODS: The molecular geometries were optimized by DFT//TDDFT D3-B3LYP/TZVP theoretical level with IEFPCM solvent model in S0 and S1 states, respectively. This work also explores the energy level of target molecules with the computational vertical absorption spectra by TDDFT. All the simulations were carried out based on Gaussian 16 software. The core-valence bifurcation (CVB) indexes were obtained by using Multiwfn 3.8. Potential energy surfaces were constructed by the DFT//TDDFT D3-B3LYP/TZVP level based on restricted optimization, also the transition state (TS) forms were searched using the same level.
RESUMO
Peptides that self-assemble exhibit distinct three-dimensional structures and attributes, positioning them as promising candidates for biocatalysts. Exploring their catalytic processes enhances our comprehension of the catalytic actions inherent to self-assembling peptides, laying a theoretical foundation for creating novel biocatalysts. The investigation into the intricate reaction mechanisms of these entities is rendered challenging due to the vast variability in peptide sequences, their aggregated formations, supportive elements, structures of active sites, types of catalytic reactions, and the interplay between these variables. This complexity hampers the elucidation of the linkage between sequence, structure, and catalytic efficiency in self-assembling peptide catalysts. This chapter delves into the latest progress in understanding the mechanisms behind peptide self-assembly, serving as a catalyst in hydrolysis and oxidation reactions, and employing computational analyses. It discusses the establishment of models, selection of computational strategies, and analysis of computational procedures, emphasizing the application of modeling techniques in probing the catalytic mechanisms of peptide self-assemblies. It also looks ahead to the potential future trajectories within this research domain. Despite facing numerous obstacles, a thorough investigation into the structural and catalytic mechanisms of peptide self-assemblies, combined with the ongoing advancement in computational simulations and experimental methodologies, is set to offer valuable theoretical insights for the development of new biocatalysts, thereby significantly advancing the biocatalysis field.