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1.
Toxicol Appl Pharmacol ; 483: 116817, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38215995

RESUMO

d-Tetramethrin is one of the main components of mosquito control products, and is widely used for the control of dengue fever and insecticide production. Due to its widespread use, d-tetramethrin is a ubiquitous environmental pollutant and poses potential risks to human health. However, the effects of d-tetramethrin on liver morphology and function are not clearly established. In this study, we used zebrafish as an animal model to analyze the acute and chronic effects of d-tetramethrin exposure on the liver. We exposed zebrafish larvae and adults to different concentrations of d-tetramethrin and examined the impact of d-tetramethrin on lipid and glycogen metabolism, cellular properties, oxidative stress, cell proliferation, and apoptosis in the liver. We also analyzed transcriptional changes in genes related to apoptosis, inflammation, and cell proliferation using qPCR. Zebrafish exposed to d-tetramethrin exhibited severe liver damage, as evidenced by the presence of vacuoles and nuclear distortion in liver cells. The liver area in zebrafish larvae of the treatment group was significantly smaller than that of the control group. Significant lipid accumulation and decreased glycogen levels were observed in the livers of both zebrafish larvae and adults exposed to d-tetramethrin. Furthermore, d-tetramethrin exposure induced apoptosis and inflammation in zebrafish embryos. Additionally, d-tetramethrin caused liver damage, metabolic dysfunction, and impaired liver function. These results suggest that d-tetramethrin induces liver toxicity in zebrafish, by inducing oxidative stress and inhibiting cell proliferation.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Piretrinas , Peixe-Zebra , Animais , Humanos , Peixe-Zebra/metabolismo , Estresse Oxidativo , Inflamação , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Proliferação de Células , Glicogênio/metabolismo , Glicogênio/farmacologia , Lipídeos , Larva
2.
Phytochem Anal ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38725319

RESUMO

INTRODUCTION: Previously reported preparation methods of Ginkgo biloba leaf extract (EGBL) have mainly focused on the enrichment of flavonoid glycosides (FG) and terpene trilactones (TT), which led to the underutilization of G. biloba leaves (GBL). OBJECTIVES: To make full use of GBL, in this study, a comprehensive optimization strategy for preparing EGBL by macroporous resin column chromatography was proposed and applied to enrich FG, TT, and shikimic acid (SA) from GBL. METHODOLOGY: Initially, the static adsorption and desorption were executed to select suitable resin. Then, the influences of solution pH were investigated by the static and dynamic adsorption. Subsequently, eight process parameters were systematically investigated via a definitive screening design (DSD). After verification experiments, scale-up enrichment was carried out, investigating the feasibility of the developed strategy for application on an industrial scale. RESULTS: It was found that XDA1 was the most appropriate adsorbent for the preparation of EGBL at solution pH 2.0. Furthermore, based on the constraints of the desired quality attributes, the optimized ranges of operating parameters were successfully acquired, and the verification experiments demonstrated the accuracy and reliability of using DSD to investigate the chromatography process for the preparation of EGBL. Finally, magnified experiments were successfully performed, obtaining the EGBL containing 26.54% FG, 8.96% TT, and 10.70% SA, which reached the SA level of EGB761, an international standard EGBL. CONCLUSION: The present study not only provided an efficient and convenient approach for the preparation of EGBL enriched in SA but also accelerated efforts to high-value utilization of GBL.

3.
Opt Express ; 31(15): 24469-24480, 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37475273

RESUMO

In this paper, we use weak measurement to study the mixed magneto-optical Kerr effects (MOKEs) in a magnetic single layer of Co and in organic/Co bilayer films. The relationship between the amplified shift and the MOKE parameters is theoretically established and then experimentally observed as a function of both the magnetization intensity and the magnetization direction in magnetic thin films with an arbitrary magnetization. Furthermore, we experimentally observe a magnetic coupling at the organic/ferromagnetic interface. Due to this being a robust coupling, there is a significant dependence of the amplified shift with the thickness of the organic layer. This work has value for its application in the magnetic measurement technique for the more general case based on weak measurement.

4.
Phys Chem Chem Phys ; 25(14): 9909-9924, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36946889

RESUMO

We have studied the two phases of the molecular crystal acetylene, C2H2, using calculations of the lattice dynamics by Density Functional Theory methods. together with the use of classical molecular dynamics (MD) simulation methods. The two phases share the same simple face-centred cubic lattice arrangement of the molecular centres of mass, but with different molecular orientations. We show that the higher-temperature phase has lower phonon frequencies and hence higher entropy, giving thermodynamic stability at higher temperature. The calculated lattice dynamics of this phase show instabilities associated with phonons involving pure rotations of the molecules. The MD results show large amplitudes of librational motion in this phase. The MD simulations also showed a potential phase transition to a structure of tetragonal symmetry. The picture that emerges is that the phase transition in acetylene is a very rare example of one that encompasses elements of three types of transition: displacive, order-disorder and reconstructive.

5.
Plant Dis ; 106(11): 2967-2973, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35306849

RESUMO

Rice false smut caused by the filamentous fungus Ustilaginoidea virens is a devastating grain disease in rice. Fungicides have been an important measure for the control of this disease. In this study, baseline sensitivities of 179 isolates of U. virens to the quinone outside inhibitor (QoI) fungicides azoxystrobin and pyraclostrobin were established. The distribution of the 50% effective concentration (EC50) values of each fungicide was unimodal. The frequency distribution of logarithmically transformed EC50 values fit or fit closer to a normal distribution. The ranges of EC50 values for azoxystrobin and pyraclostrobin were 0.001 to 0.864 and 0.001 to 0.569 µg/ml, with means and standard errors of the mean values of 0.203 ± 0.012 and 0.079 ± 0.006 µg/ml, respectively. There was a statistically significant and moderately positive correlation (n = 100, r = 0.469, P = 0.001) in sensitivity between these two fungicides. No cross-resistance was found between azoxystrobin, pyraclostrobin, and carbendazim or sterol demethylation inhibitor fungicides. Each fungicide had a significantly higher mean preventive efficacy compared with its curative efficacy. Field assays showed that the control efficacy of pyraclostrobin against rice false smut was greater than that of azoxystrobin. Pyraclostrobin had the best control of rice false smut in three rice varieties, with the control efficacy ranging from 81.5 to 95.5%, whereas azoxystrobin decreased the disease index by 64.1 to 69.2% under the same conditions. These results provide us a reference point in the management of U. virens and future QoI fungicide resistance monitoring programs.


Assuntos
Fungicidas Industriais , Oryza , Fungicidas Industriais/farmacologia , Oryza/microbiologia , Quinonas
6.
Angew Chem Int Ed Engl ; 61(39): e202209615, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-35909255

RESUMO

It is not resolved which model describes better the aqueous-phase nucleation and growth of semiconductor quantum dots (QDs), the classical one-step one or the nonclassical multi-step one. Here, we design a room-temperature reaction to trap reaction intermediates in the prenucleation stage of ZnSe QDs (as a model system). We show that the trapped intermediate can transform to magic-size clusters (MSCs) via intra-molecular reorganization and can fragment to enable the growth of QDs. The MSCs exhibit a sharp optical absorption peaking at 299 nm, labelled MSC-299. The intermediate, the precursor compound (PC-299) of MSC-299, is optically transparent at 299 nm and to longer wavelengths. This intermediate forms in various Zn and Se reaction systems. The present study provides unambiguous evidence that the nonclassical and classical pathways are both necessary to explain the nucleation and growth of aqueous-phase QDs, with the former pathway favored more by high reaction concentrations.

7.
Biomed Chromatogr ; 35(10): e5170, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33982313

RESUMO

Previously reported HPLC-evaporative light scattering detection methods for terpene trilactone determination in Ginkgo biloba leaf extract (EGBL) have complicated sample preparation steps and are time-consuming. Thus, in this work, an HPLC-MS method for the determination of terpene trilactones in EGBL was developed with a novel analytical quality by design approach to provide robust and simple measurements. For this purpose, analytical target profiles and systematic risk analyses were performed to identify potential critical method attributes and critical method parameters. After screening experiments, a Box-Behnken design approach was utilized to investigate the relationships between critical method attributes and critical method parameters. A hypercube design space obtained by a Monte Carlo method was used for choosing the analytical control strategy. Then, verification experiments were performed within the design space, and the models were found to be accurate. After that, the optimized method was verified and successfully used for quality control analysis of EGBL from different manufacturers, and the results were almost the same as those determined by HPLC-evaporative light scattering detection. To our knowledge, this is the first study to establish a robust HPLC-MS method for determination of terpene trilactones in EGBL based on a novel analytical quality by design concept, which can improve the quality control of commercial EGBL.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Lactonas/análise , Espectrometria de Massas/métodos , Extratos Vegetais/química , Terpenos/análise , Ginkgo biloba , Projetos de Pesquisa
8.
Phytochem Anal ; 32(6): 942-956, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33660329

RESUMO

INTRODUCTION: Charged aerosol detection (CAD) has the merits of high sensitivity, high universality and response uniformity. The strategy that combines the quantitative analysis of multi-components by single marker (QAMS) with CAD has certain advantages for the quantification of multi-components. However, relevant research was limited. OBJECTIVES: To comprehensively investigate the crucial factors that affect the performance of the HPLC-CAD-QAMS approach and validate the credibility and feasibility of the method. METHODOLOGY: Multiple components of Qishen Yiqi dripping pills (QSYQ) were assayed using the high-performance liquid chromatography (HPLC)-CAD-QAMS approach. Some factors that affect the sensitivity and accuracy of the approach were sufficiently studied. After the method verification, principal component analysis (PCA) was applied to evaluate the quality consistency of three types of samples: normal samples, expired samples and negative samples. RESULTS: A HPLC-CAD-QAMS method was successfully developed for the multi-component determination of QSYQ. First, chromatographic conditions were optimised by a definitive screening design, and the optimised ranges of operating parameters were obtained with a Monte Carlo simulation method. Next, a new method to select the internal reference standards was successfully introduced based on the heatmap of Pearson correlation coefficients of the response factors. Then, the multi-point method was selected to calculate the relative correction factors, and a robustness test was conducted with Plackett-Burman design. Finally, the PCA was proved to be effective for the quality consistency evaluation of different samples. CONCLUSION: The developed HPLC-CAD-QAMS method can be a reliable and superior means for the multi-component quantitative analysis of QSYQ.


Assuntos
Medicamentos de Ervas Chinesas , Aerossóis , Cromatografia Líquida de Alta Pressão , Controle de Qualidade
9.
Opt Express ; 28(20): 29086-29097, 2020 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-33114814

RESUMO

Using the spin Hall effect of light, this work proposes a measurement technique of the magnetic properties of thin films. The beam shift of the spin Hall effect of light is used to replace the magneto-optical Kerr rotation angle as a parameter to characterize the magnetism of thin films. The technique can easily achieve an accuracy of 10-6 rad of the magneto-optical Kerr rotation angle which can, in theory, be further improved to 10-8 rad. We also proposed two methods to solve the problem of the exceeding linear response region of the measurement under high magnetic field intensity, making it more conducive to practical application. This technique has great potential for application in the magnetic measurement of ultra-thin films with particular emphasis on thicknesses within several atomic layers.

10.
Phys Rev Lett ; 124(1): 010502, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31976724

RESUMO

Ensuring the nonentanglement-breaking (non-EB) property of quantum channels is crucial for the effective distribution and storage of quantum states. However, a practical method for direct and accurate certification of the non-EB feature is highly desirable. Here, we propose and verify a realistic source based measurement device independent certification of non-EB channels. Our method is resilient to repercussions on the certification from experimental conditions, such as multiphotons and imperfect state preparation, and can be implemented with an information incomplete set. We achieve good agreement between experimental outcomes and theoretical predictions, which is validated by the expected results of the ideal semiquantum signaling game, and accurately certify the non-EB channels. Furthermore, our approach is highly robust to effects from noise. Therefore, the proposed approach can be expected to play a significant role in the design and evaluation of realistic quantum channels.

11.
Phys Rev Lett ; 122(16): 160501, 2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31075015

RESUMO

Measurement-device-independent quantum key distribution (MDI-QKD) can eliminate all detector side channels and it is practical with current technology. Previous implementations of MDI-QKD all used two symmetric channels with similar losses. However, the secret key rate is severely limited when different channels have different losses. Here we report the results of the first high-rate MDI-QKD experiment over asymmetric channels. By using the recent 7-intensity optimization approach, we demonstrate>10×higher key rate than the previous best-known protocols for MDI-QKD in the situation of large channel asymmetry, and extend the secure transmission distance by more than 20-50 km in standard telecom fiber. The results have moved MDI-QKD towards widespread applications in practical network settings, where the channel losses are asymmetric and user nodes could be dynamically added or deleted.

12.
Zhongguo Zhong Yao Za Zhi ; 44(9): 1822-1828, 2019 May.
Artigo em Zh | MEDLINE | ID: mdl-31342708

RESUMO

The flower of Hibiscus syriacus has good ornamental and edible-medicinal values.In this study,four samples of two varieties,namely white multiple petals flower and pink multiple petals flower,were selected as test materials.And the optimum extraction conditions,relative molecular weight,monosaccharide composition and antioxidant activity of polysaccharides in flower were investigated.Through single factor experiment and response surface,the optimal extract conditions of polysaccharide were designed as follows:extraction temperature at 96.8℃,ratio of material to liquid of 43.5∶1 m L·g~(-1),extraction time of 3.1 h.Polysaccharides of H.syriacus flowers were analyzed by high performance gel chromatography.The average molecular masses of the 4 polysaccharide samples were1.49×10~5,1.25×10~5,1.01×10~5,1.37×10~5,respectively.Polysaccharides of H.syriacus flowers were mainly composed of glucose,mannose,galactose,rhamnose and arabinose by pre-column derivatization HPLC.The ratio of galactose was the highest in five monosaccharide,and the ratio of galactose to glucose was 1.656-4.496.In addition,crude polysaccharides of H.syriacus flowers showed potential antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)assay,total reducing capacity assay and ABTS assay in vitro,and its antioxidant effect showed a good dose-effect relationship with the concentration of crude polysaccharides.Among the tested varieties,polysaccharides of pink multiple petals flower and white multiple petals flower had the same molecular masses and monosaccharides composition,but the antioxidant activity of the polysaccharides of pink multiple petals flower was higher than that of the white flowers.The results of this study can provide a theoretical basis for the application of H.syriacus flower in the field of functional foods.


Assuntos
Antioxidantes/farmacologia , Hibiscus/química , Polissacarídeos/farmacologia , Antioxidantes/química , Flores/química , Monossacarídeos/química , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Pigmentação , Polissacarídeos/química
13.
Zhongguo Zhong Yao Za Zhi ; 43(10): 2025-2031, 2018 May.
Artigo em Zh | MEDLINE | ID: mdl-29933666

RESUMO

The study is aimed to fully analyze antioxidant activty and stability of color-related components from Dendrobium officinale flower. The contents of anthocyanins,carotenoids and flavonoids of 10 varieties including whole flower and labellum of D.officinale flower were detected using UV visible spectroscopy technique and evaluated for their 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·), superoxide anion radical (·O⁻2) and hydroxy radical (·OH) scavenging activty. And the effects of 4 kinds of metal ions (Cu²âº, Mg²âº, Al³âº,K⁺) and 2 kinds of food additives were investigated on the stability of anthocyanins pigment from D.officinale flower. The results indicated that the flower of D.officinale contained anthocyanins,carotenoids and flavonoids,and their contents in different parts of different families varied. The content of anthocyanins (1 330.9 µg·g⁻¹) in labellum was significantly higher than that in the whole flower (696.3 µg·g⁻¹). The content of carotenoids was positively correlated with the content of anthocyanins,and there was significant positive correlation between the scavenging capacities of the three free radicals and the contents of anthocyanin,respectively (0.415,0.384,0.455). The Cu²âº, Mg²âº, Al³âº, K⁺ and glucose showed significant color-enhancing effect and could increase the stability of anthocyanin in D.officinale flower,while ascorbic acids showed remarkably degradation effect of anthocyanin in D.officinale flower.


Assuntos
Antioxidantes/análise , Dendrobium/química , Flores/química , Antocianinas/análise , Carotenoides/análise , Flavonoides/análise , Compostos Fitoquímicos/análise
14.
Tumour Biol ; 39(2): 1010428317691680, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28222667

RESUMO

Curcumin, a major yellow pigment and spice in turmeric and curry, is a powerful anti-cancer agent. The anti-tumor activities of curcumin include inhibition of tumor proliferation, angiogenesis, invasion and metastasis, induction of tumor apoptosis, increase of chemotherapy sensitivity, and regulation of cell cycle and cancer stem cell, indicating that curcumin maybe a strong therapeutic potential through modulating various cancer progression. It has been reported that microRNAs as small noncoding RNA molecules are related to cancer progression, which can be regulated by curcumin. Dysregulated microRNAs play vital roles in tumor biology via regulating expressions of target genes and then influencing multiple cancer-related signaling pathways. In this review, we focused on the inhibition effect of curcumin on various cancer progression by regulating expression of multiple microRNAs. Curcumin-induced dysregulation of microRNAs may activate or inactivate a set of signaling pathways, such as Akt, Bcl-2, PTEN, p53, Notch, and Erbb signaling pathways. A better understanding of the relation between curcumin and microRNAs may provide a potential therapeutic target for various cancers.


Assuntos
Curcumina/farmacologia , MicroRNAs/biossíntese , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Curcumina/uso terapêutico , Progressão da Doença , Humanos , MicroRNAs/genética , Neoplasias/genética , Neoplasias/metabolismo , Ensaios Clínicos Controlados Aleatórios como Assunto
15.
Anal Bioanal Chem ; 409(23): 5547-5554, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28717898

RESUMO

The thiophene-modified rhodamine 6G (GYJ) has been synthesized as a novel chemosensor. The sensor has sufficiently high selectivity and sensitivity for the detection of Fe3+ and Al3+ ions (M3+) by fluorescence and ultraviolet spectroscopy with a strong ability for anti-interference performance. The binding ratio of M3+-GYJ complex was determined to be 2:1 according to the Job's plot. The binding constants for Fe3+ and Al3+ were calculated to be 3.91 × 108 and 5.26 × 108 M-2, respectively. All these unique features made it particularly favorable for cellular imaging applications. The obvious fluorescence microscopy experiments demonstrated that the probes could contribute to the detection of Fe3+ and Al3+ in related cells and biological organs with satisfying resolution. Graphical abstract GYJ has high selectivity and sensitivity for the detection of Fe(III) and Al(III) with the binding ratio of 2:1.


Assuntos
Alumínio/análise , Compostos Férricos/análise , Corantes Fluorescentes/química , Rodaminas/química , Tiofenos/química , Limite de Detecção , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
16.
Zhongguo Zhong Yao Za Zhi ; 42(20): 3919-3925, 2017 Oct.
Artigo em Zh | MEDLINE | ID: mdl-29243428

RESUMO

In order to provide new information on polysaccharide in Dendrobium officinale flowers,the monosaccharide composition and relative molecular mass distribution of 11 families of flowers were investigated and analyzed by high performance gel filtration chromatography (HPGFC) and pre-column derivatization ultra performance liquid chromatography (UPLC) in this study. Then cluster analysis was carried out for the monosaccharide peak areas by utilizing SPSS 19.0 software. The results showed that the polysaccharides of all the above 11 hybrid families of D. officinale flower were separated into three fractions (DOP-1, DOP-2 and DOP-3) with the average relative molecular mass of 5.53×105, 3.49×105 and 2.12×105. The polysaccharides in 11 different families were mainly composed of glucose, mannose, galactose, galacturonic acid and arabinose; mannose had the highest proportion among them, with mannose/glucose ratio of 0.302-3.335. Additionally, the relative contents of various monosaccharides in different families varied. 11 families of D. officinale flower could be classified into four categories according to their monosaccharide components and relative contents. In this study, the relative molecular mass distribution and monosaccharide composition of polysaccharides in D. officinale flowers were defined, which can provide foundations for its resource utilization..


Assuntos
Dendrobium/química , Flores/química , Monossacarídeos/química , Polissacarídeos/química , Manose
17.
Cereb Cortex ; 25(2): 423-32, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24008582

RESUMO

Spatial encoding in the hippocampus is multifactorial, and it is well established that metric information about space is conferred by place cells that fire when an animal finds itself in a specific environmental location. Visuospatial contexts comprise a key element in the formation of place fields. Nevertheless, hippocampus does not only use visual cues to generate spatial representations. In the absence of visual input, both humans and other vertebrates studied in this context, are capable of generating very effective spatial representations. However, little is known about the relationship between nonvisual sensory modalities and the establishment of place fields. Substantial evidence exists that olfactory information can be used to learn spatial contexts. Here, we report that learning about a distinct odor constellation in an environment, where visual and auditory cues are suppressed, results in stable place fields that rotate when the odor constellations are rotated and remap when the odor constellations are shuffled. These data support that the hippocampus can use nonvisuospatial resources, and specifically can use spatial olfactory information, to generate spatial representations. Despite the less precise nature of olfactory stimuli compared with visual stimuli, these can substitute for visual inputs to enable the acquisition of metric information about space.


Assuntos
Hipocampo/fisiologia , Neurônios/fisiologia , Percepção Olfatória/fisiologia , Aprendizagem Espacial/fisiologia , Potenciais de Ação , Animais , Eletrodos Implantados , Masculino , Odorantes , Ratos Wistar , Rotação
18.
Phys Chem Chem Phys ; 17(27): 18159-66, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-26102508

RESUMO

We report an advanced chemical vapour deposition approach which allows the direct in situ synthesis of cm-length ultrathin buckypapers comprising carbon nanostructures filled with Fe3C, FeCo, FeNi, CoNi, Co and Ni by sublimation and pyrolysis of single or combined metallocenes with very low quantities of dichlorobenzene. As a result, extremely high saturation magnetizations of 117 emu g(-1), 90 emu g(-1) and 80 emu g(-1) are obtained for the specific cases of Fe3C, FeCo and FeNi, respectively, while variable saturation magnetizations of 70 emu g(-1), 58 emu g(-1) and 6.7 emu g(-1) are obtained for Co, CoNi and Ni respectively.

19.
Hippocampus ; 24(11): 1330-40, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24910241

RESUMO

The metabotropic glutamate (mGlu) receptors are critically involved in enabling the persistency of forms of synaptic plasticity that are believed to underlie hippocampus-dependent memory. These receptors and in particular, mGlu5, are also required for hippocampus-dependent learning and memory. In the hippocampus, synaptic plasticity is one of the mechanisms by which spatial information may be represented. Another mechanism involves increased firing of place cells. Place cells increase their firing activity when an animal is in a specific spatial location. Inhibition of factors that are essential for synaptic plasticity, such as N-methyl-d-aspartate receptors or protein synthesis, also impair place cell activity. This raises the question as to whether mGlu receptors, that are so important for synaptic plasticity and spatial memory, are also important for place cell encoding. We examined location-dependent place cell firing i.e. place fields. We observed that antagonism of mGlu5, using 2-methyl-6-(phenylethynyl) pyridine (MPEP) had no effect on place field profiles in a familiar environment. However, in a novel environment mGlu5-antagonism affected long-term place field stability, reduced place cell firing and spatial information. These data strongly suggest a role for mGlu5 in the mechanisms underlying informational content and long-term stability of place fields, and add to evidence supporting the importance of these receptors for hippocampal function.


Assuntos
Região CA1 Hipocampal/fisiologia , Neurônios/fisiologia , Receptor de Glutamato Metabotrópico 5/metabolismo , Percepção Espacial/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Região CA1 Hipocampal/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Masculino , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/fisiologia , Neurônios/efeitos dos fármacos , Testes Neuropsicológicos , Piridinas/farmacologia , Ratos Wistar , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Reconhecimento Psicológico/efeitos dos fármacos , Reconhecimento Psicológico/fisiologia , Percepção Espacial/efeitos dos fármacos
20.
Artigo em Inglês | MEDLINE | ID: mdl-38652581

RESUMO

The bromide-chloride mixed quasi-two-dimensional (2D) perovskite, with a natural quantum well structure and tunable exciton binding energy, has gained significant attention for high-performance blue perovskite light-emitting diodes (PeLEDs). However, the relative importance of having a low trap state density or efficient exciton transfer for high-efficiency electroluminescence (EL) performance remains elusive. Here, two molecules with the benzoic acid group, sodium 4-fluorobenzoate (SFB) and 3,5-dibromobenzoic acid (DBA), are used to modulate the phase distribution and trap state to explore the effect between energy transfer and defect passivation. As a result, when the n = 1 phase is inhibited in both films, the DBA@SFB-modified perovskite films achieve a higher photoluminescence quantum yield (PLQY) than the SFB-modified perovskite films due to effective defect passivation. However, DBA@SFB-modified PeLEDs exhibit lower external quantum efficiency (EQE) compared to SFB-modified PeLEDs due to the poor exciton transfer between the low-dimensional phase. This demonstrates that passivation strategies may enhance photoluminescence through reducing nonradiative recombination, but the effect of phase distribution is pivotal for EL performance by efficient energy transfer in quasi-2D perovskites. Femtosecond time-resolved transient absorption measurements confirm the fastest carrier dynamics in SFB-modified perovskite films, further corroborating the above result. This work provides useful information about phase modulation and defect passivation for high-efficiency blue quasi-2D PeLEDs.

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