Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 154
Filtrar
2.
Small Methods ; 8(1): e2301013, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37891712

RESUMO

Carbon dots (CDs), as emerging long afterglow luminescent material, have attracted the attention of researchers and become one of the hot topics in long afterglow materials. In recent years, researchers have obtained a series of CDs-based long afterglow materials with different properties utilizing matrix-assisted and self-protective methods. To meet diverse application needs, the development of multicolor CDs-based long afterglow materials is a focus and challenge in this field. Most of the previously reported CDs-based long afterglow materials generally emit blue or green afterglow. Recently, some multicolor systems have been discovered, and the emission range can extend from ultraviolet to near-infrared. However, there is a lack of systematic and in-depth analysis regarding the preparation strategy and luminescence mechanism of multicolor afterglow from CDs-based long afterglow materials. Based on this, this review summarizes the preparation strategies of multicolor afterglow from raw materials and reaction parameters. Then, the luminescence mechanisms of multicolor afterglow are analyzed from seven factors, including carbonization degree, surface state, aggregation degree, temperature dependence, excitation dependence, multi-emission center, and energy transfer. Moreover, the applications of multicolor afterglow from CDs-based long afterglow materials are introduced. Finally, the problems and challenges in this field are discussed, and the future development directions are analyzed.

3.
Mater Horiz ; 11(1): 113-133, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-37856234

RESUMO

Carbon dots (CDs) are a new type of quasi-spherical and zero-dimension carbon nanomaterial with a diameter less than 10 nm. They exhibit a broad absorption spanning from the ultraviolet (UV) to visible light regions and inspire growing interests due to their excellent performance. In recent years, it was identified that the CDs embedded in various inorganic matrices (IMs) can effectively activate afterglow emission by suppressing the nonradiative transitions of molecules and protecting the triplet excitons of CDs, which hold broad application prospects. Herein, recent advances in CDs@IMs are reviewed in detail, and the interaction and luminescence mechanisms between CDs and IMs are also summarized. We highlight the synthetic strategies of constructing composites and the roles of IMs in facilitating the applications of CDs in diverse areas. Finally, some directions and challenges of future research in this field are proposed.

4.
Angew Chem Int Ed Engl ; 63(4): e202308951, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38052724

RESUMO

Nanohybrid photosystems have advantages in converting solar energy into electricity, while natural photosystems based solar-powered energy-storage device is still under developed. Here, we fabricate a new kind of photo-rechargeable zinc-ion hybrid capacitor (ZHC) benefiting from light-harvesting carbon dots (CDs) and natural thylakoids for realizing solar energy harvesting and storage simultaneously. Under solar light irradiation, the embedded CDs in thylakoids (CDs/Thy) can convert the less absorbed green light into highly absorbed red light for thylakoids, besides, Förster resonance energy transfer (FRET) between CDs and Thy also occurs, which facilitates the photoelectrons generation during thylakoids photosynthesis, thereby resulting in 6-fold photocurrent output in CDs/Thy hybrid photosystem, compared to pristine thylakoids. Using CDs/Thy as the photocathode in ZHCs, the photonic hybrid capacitor shows photoelectric conversion and storage features. CDs can improve the photo-charging voltage response of ZHCs to ≈1.2 V with a remarkable capacitance enhancement of 144 % under solar light. This study provides a promising strategy for designing plant-based photonic and electric device for solar energy harvesting and storage.

5.
Plant Physiol Biochem ; 206: 108299, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38150840

RESUMO

Cadmium (Cd), which is a nonessential heavy metal element for organisms, can have a severe impact on the growth and development of organisms that absorb excessive Cd. Studies have shown that Brassica carinata, a semiwild oil crop, has strong tolerance to various abiotic stresses, and RNA-seq has revealed that the B. carinata superoxide dismutase gene (BcaSOD1) likely responds to Cd stress. To elucidate the BcaSOD1 function involved in tolerance of Cd stress, we cloned the coding sequences of BcaSOD1 from a purple B. carinata accession and successfully transferred it into Arabidopsis thaliana. The subcellular localization results demonstrated that BcaSOD1 was primarily located in the plasma membrane, mitochondria and nucleus. Overexpression of BcaSOD1 in transgenic Arabidopsis (OE) effectively decreased the toxicity caused by Cd stress. Compared to the WT (wild type lines), the OE lines exhibited significantly increased activities of antioxidant enzymes (APX, CAT, POD, and SOD) after exposure to 2.5 mM CdCl2. The Cd content of underground (root) in the OE line was dominantly higher than that in the WT; however, the Cd content of aboveground (shoot) was comparable between the OE and WT types. Moreover, the qRT‒PCR results showed that several heavy metal detoxification-related genes (AtIREG2, AtMTP3, AtHMA3, and AtNAS4) were significantly upregulated in the roots of OE lines under Cd treatment, suggesting that these genes are likely involved in Cd absorption in the roots of OE lines. In addition, both comparable transcriptome and qRT-PCR analyses revealed that exogenous BcaSOD1 noticeably facilitates detoxification by stimulating the expression of two arginine (Arg) biosynthesis genes (AtGDH1 and AtGDH2) while inhibiting the expression of AtARGAH1, a negative regulator in biosynthesis of Arg. The Arg content was subsequently confirmed to be significantly enhanced in OE lines under Cd treatment, indicating that BcaSOD1 likely strengthened Cd tolerance by regulating the expression of Arg-related genes. This study demonstrates that BcaSOD1 can enhance Cd tolerance and reveals the molecular mechanism of this gene, providing valuable insights into the molecular mechanism of Cd tolerance in plants.


Assuntos
Arabidopsis , Metais Pesados , Cádmio/toxicidade , Cádmio/metabolismo , Arabidopsis/metabolismo , Superóxido Dismutase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Metais Pesados/toxicidade , Metais Pesados/metabolismo , Arginina/genética , Arginina/metabolismo
6.
Small ; : e2306323, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38039497

RESUMO

Room temperature phosphorescent (RTP) materials with long-lived, excitation-dependent, and time-dependent phosphorescence are highly desirable but very hard to achieve. Herein, this work reports a rational strategy of multiple wavelength excitation and time-dependent dynamic RTP color by confining silane-functionalized carbon dots (CDs) in a silica matrix (Si-CDs@SiO2 ). The Si-CDs@SiO2 possesses unique green-light-excitation and a change in phosphorescence color from yellow to green. A slow-decaying phosphorescence at 500 nm with a lifetime of 1.28 s and a fast-decaying phosphorescence at 580 nm with a lifetime of 0.90 s are observed under 365 nm of irradiation, which originated from multiple surface triplet states of the Si-CDs@SiO2 . Given the unique dynamic RTP properties, the Si-CDs@SiO2 are demonstrated for applications in fingerprint recognition and multidimensional dynamic information encryption. These findings will open an avenue to explore dynamic phosphorescent materials and significantly broaden their applications.

7.
Physiol Plant ; 175(6): e14072, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38148219

RESUMO

Under global warming, the availability of water resources is one of the most important factors affecting trait evolution and plant species distribution across terrestrial ecosystems, and the relationships between drought resistance strategies and the hydrological niche characteristics of plants are worth studying. We continuously monitored physiological drought response parameters such as gs , Tr , proline, soluble sugar, gene expression and activities of SOD, POD, and CAT to assess drought resistance strategies of Platycarya longipes and Lindera communis; determined plant soil hydrological niche separation by stable H and O isotope analysis; and analysed the effects of interspecific water competition by comparing the differences in morphological and physiological parameters between solo and mixed planting. Under drought stress, L. communis exhibited a drought avoidance strategy, and P. longipes exhibited a drought tolerance strategy. L. communis utilized the water within the shallow soil layer, while P. longipes mainly utilized the water in the deeper soil layer; there were fewer parameters with significant differences between the solo planting and the mixed planting of L. communis compared to P. longipes. Overall, P. longipes benefited from coexistence with L. communis under drought stress, which may be because L. communis employs a drought avoidance strategy, reducing soil water consumption in the drought environment. These results suggested that differences in functional traits or resistance strategies among species benefit species' coexistence in a community under drought stress.


Assuntos
Secas , Ecossistema , Solo , Plantas/metabolismo , Água/metabolismo
8.
Nanoscale ; 15(41): 16561-16570, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37819234

RESUMO

0D copper-based perovskites (Cs3Cu2I5) have fascinating optical properties, such as strong exciton binding energy, high photoluminescence quantum yield (PLQY) and large Stokes shifts from self-trapped excitons (STEs), which make them highly considerable candidates in the field of lighting. However, the stability of Cs3Cu2I5 is compromised by the oxidation of Cu+ to Cu2+ during the storage or operation process. Here, we proposed a ligand engineering strategy to improve the stability of Cs3Cu2I5via an organic molecule (ethylenediaminetetraacetic acid, EDTA) with multiple functional groups. The strong interaction between carboxyl groups and Cu+ was evidenced through FTIR and XPS, and it could retard monovalent copper oxidation. After storing for 90 days, the EDTA-engineered Cs3Cu2I5 (EDTA-Cs3Cu2I5) maintained its original crystalline structure, while the control Cs3Cu2I5 exhibited an impurity phase. Through quantitative analysis, the content of Cu2+ in EDTA-Cs3Cu2I5 was found to be 83.9% lower than that in control Cs3Cu2I5. Benefiting from the inhibition of Cu+ oxidation, EDTA-Cs3Cu2I5 exhibited improved light emission stability. For example, the optimized EDTA-Cs3Cu2I5 retained 74.7% of the initial photoluminescence (PL) intensity after 90-day storage under ambient conditions, while the pure Cs3Cu2I5 retained only 41.7%. Furthermore, EDTA could passivate defects and enhance the PL properties of the optimized Cs3Cu2I5, which showed a PLQY of 94.7%, much higher than that of 71.4% for pure Cs3Cu2I5. We further constructed a WLED based on the EDTA-engineered Cs3Cu2I5, which showed CIE at (0.3238, 0.3354), a CRI of 91.7, and a T50 of 361 h. The proposed EDTA ligand strategy provides a new way to regulate the light-emitting properties and stabilities of Cs3Cu2I5 for future industrialization.

9.
JACS Au ; 3(8): 2291-2298, 2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37654575

RESUMO

Carbon dot (CD)-based luminescent materials have attracted great attention in optical anti-counterfeiting due to their excellent photophysical properties in response to ultraviolet-to-visible excitation. Hence, there is an urgent need for the general synthesis of CD-based materials with multimode luminescence properties and high stability; however, their synthesis remains a formidable challenge. Herein, CDs were incorporated into a Yb,Tm-doped YF3 matrix to prepare CDs@YF3:Yb,Tm composites. The YF3 plays a dual role, not only serving as a host for fixing rare earth luminescent centers but also functioning as a rigid matrix to stabilize the triplet state of the CDs. Under the excitation of 365 nm ultraviolet light and 980 nm near-infrared light, CDs@YF3:Yb,Tm exhibited blue fluorescence and green room-temperature phosphorescence of CDs and upconversion luminescence of Tm3+, respectively. Due to the strong protection of the rigid matrix, the stability of CDs@YF3:Yb,Tm is greatly improved. This work provides a general synthesis strategy for achieving multimode luminescence and high stability of CD-based luminescent materials and offers opportunities for their applications in advanced anti-counterfeiting and information encryption.

10.
J Exp Clin Cancer Res ; 42(1): 242, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37723588

RESUMO

BACKGROUND: Glioma exhibit heterogeneous susceptibility for targeted ferroptosis. How circRNAs alterations in glioma promote iron metabolism and ferroptosis defense remains unclarified. METHODS: The highly enriched circRNAs in glioblastoma (GBM) were obtained through analysis of sequencing datasets. Quantitative real-time PCR (qRT-PCR) was used to determine the expression of circRNF10 in glioma and normal brain tissue. Both gain-of-function and loss-of-function studies were used to assess the effects of circRNF10 on ferroptosis using in vitro and in vivo assays. The hypothesis that ZBTB48 promotes ferroptosis defense was established using bioinformatics analysis and functional assays. RNA pull-down and RNA immunoprecipitation (RIP) assays were performed to examine the interaction between circRNF10 and target proteins including ZBTB48, MKRN3 and IGF2BP3. The posttranslational modification mechanism of ZBTB48 was verified using coimmunoprecipitation (co-IP) and ubiquitination assays. The transcription activation of HSPB1 and IGF2BP3 by ZBTB48 was confirmed through luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays. The stabilizing effect of IGF2BP3 on circRNF10 was explored by actinomycin D assay. Finally, a series of in vivo experiments were performed to explore the influences of circRNF10 on the glioma progression. RESULTS: A novel circular RNA, hsa_circ_0028912 (named circRNF10), which is significantly upregulated in glioblastoma tissues and correlated with patients' poor prognosis. Through integrated analysis of the circRNA-proteins interaction datasets and sequencing results, we reveal ZBTB48 as a transcriptional factor binding with circRNF10, notably promoting upregulation of HSPB1 and IGF2BP3 expression to remodel iron metabolism and facilitates the launch of a circRNF10/ZBTB48/IGF2BP3 positive feedback loop in GSCs. Additionally, circRNF10 can competitively bind to MKRN3 and block E3 ubiquitin ligase activity to enhance ZBTB48 expression. Consequently, circRNF10-overexpressed glioma stem cells (GSCs) display lower Fe2+ accumulation, selectively priming tumors for ferroptosis evading. CONCLUSION: Our research presents abnormal circRNAs expression causing a molecular and metabolic change of glioma, which we leverage to discover a therapeutically exploitable vulnerability to target ferroptosis.


Assuntos
Ferroptose , Glioblastoma , Glioma , Humanos , Glioblastoma/genética , Retroalimentação , Ferroptose/genética , RNA Circular/genética , Glioma/genética , Ferro , Proteínas de Ligação a DNA , Fatores de Transcrição , Ubiquitina-Proteína Ligases
11.
Hand Surg Rehabil ; 42(6): 530-535, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37776975

RESUMO

PURPOSE: This study aimed to introduce a technique of external fixation using a combination of bone cement and K-wires, to treat pathological fractures related to solitary digital enchondroma close to the finger joints. METHODS: From October 2015 to January 2021, 21 patients (8 males and 13 females) with acute pathological fracture due to solitary digital enchondroma close to the finger joints were treated with cemented K-wire external fixators. Mean age was 32 (19-51) years. The digits involved were the index (n = 4), long (n = 4), ring (n = 6), and little (n = 7) fingers. Time to bone healing and complications were assessed. At final follow-up, active range of motion, grip strength and key pinch strength of the tumor-involved and contralateral healthy digits were measured and compared. Functional outcomes were evaluated on Takigawa criteria. Pain was measured on a 10-cm visual analog scale. We assessed the affected upper extremity on the Musculoskeletal Tumor Society score questionnaire. RESULTS: Mean bone healing time was 5.5 (4-8) weeks. Pin site infection was observed in 1 patient and cured with dressing changes. Mean follow-up was 34 months, with no recurrences or refractures. Mean active range of motion of the proximal interphalangeal joint, grip and key pinch strength of the involved digits reached 92%, 97%, and 99% of the contralateral digits, respectively. On Takigawa criteria, 20 functional results were excellent and 1 good. Mean pain score was 1 (0-3) cm. Mean Musculoskeletal Tumor Society score was 95 (80-100). CONCLUSION: The combination of bone cement and K-wires is a reliable technique for pathological fracture related to solitary enchondroma close to the joints of the digits, leading to good functional outcomes. LEVEL OF EVIDENCE: Therapeutic study, Level IVa.


Assuntos
Condroma , Fraturas Ósseas , Fraturas Espontâneas , Masculino , Feminino , Humanos , Adulto , Fixadores Externos , Cimentos Ósseos , Fixação de Fratura , Fraturas Ósseas/cirurgia , Condroma/diagnóstico por imagem , Condroma/cirurgia , Dor
12.
Front Mol Biosci ; 10: 1079029, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37388247

RESUMO

This paper describes performance enhancement developments to a closed-loop pump-driven wire-guided flow jet (WGJ) for ultrafast X-ray spectroscopy of liquid samples. Achievements include dramatically improved sample surface quality and reduced equipment footprint from 7 × 20 cm2 to 6 × 6 cm2, cost, and manufacturing time. Qualitative and quantitative measurements show that micro-scale wire surface modification yields significant improvements to the topography of the sample liquid surface. By manipulating their wettability, it is possible to better control the liquid sheet thickness and to obtain a smooth liquid sample surface, as demonstrated in this work.

13.
ACS Appl Mater Interfaces ; 15(24): 29140-29148, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37303115

RESUMO

The development of promising solid-state lithium batteries has been a challenging task mainly due to the poor interfacial contact and high interfacial resistance at the electrode/solid-state electrolyte (SSE) interface. Herein, we propose a strategy for introducing a class of covalent interactions with varying covalent coupling degrees at the cathode/SSE interface. This method significantly reduces interfacial impedances by strengthening the interactions between the cathode and SSE. By adjusting the covalent coupling degree from low to high, an optimal interfacial impedance of 33 Ω cm-2 was achieved, which is even lower than the interfacial impedance using liquid electrolytes (39 Ω cm-2). This work offers a fresh perspective on solving the interfacial contact problem in solid-state lithium batteries.

14.
Small ; 19(43): e2303344, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37376809

RESUMO

Developing solid-state electrolyte with sufficient ionic conduction and flexible-intimate interface is vital to advance fast-charging solid-state lithium batteries. Solid polymer electrolyte yields the promise of interfacial compatibility, yet its critical bottleneck is how to simultaneously achieve high ionic conductivity and lithium-ion transference number. Herein, single-ion conducting network polymer electrolyte (SICNP) enabling fast charging is proposed to positively realize fast lithium-ion locomotion with both high ionic conductivity of 1.1 × 10-3 S cm-1 and lithium-ion transference number of 0.92 at room temperature. Experimental characterization and theoretical simulations demonstrate that the construction of polymer network structure for single-ion conductor not only facilitates fast hopping of lithium ions for boosting ionic kinetics, but also enables a high dissociation level of the negative charge for lithium-ion transference number close to unity. As a result, the solid-state lithium batteries constructed by coupling SICNP with lithium anodes and various cathodes (e.g., LiFePO4 , sulfur, and LiCoO2 ) display impressive high-rate cycling performance (e.g., 95% capacity retention at 5 C for 1000 cycles in LiFePO4 |SICNP|lithium cell) and fast-charging capability (e.g., being charged within 6 min and discharged over than 180 min in LiCoO2 |SICNP|lithium cell). Our study provides a prospective direction for solid-state electrolyte that meets the lithium-ion dynamics for practical fast-charging solid-state lithium batteries.

15.
Macromol Rapid Commun ; 44(12): e2300019, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37027787

RESUMO

Dithieno[3',2':3,4;2",3":5,6]benzo[1,2-c][1,2,5]thiadiazole (DTBT) is a newly emerging building block to construct effective photovoltaic polymers. Organic solar cells (OSCs) based on DTBT-based polymers have realized power conversion efficiency (PCEs) over 18%, despite their relatively low open-circuit voltage (VOC ) of 0.8-0.95 V. To extend the application of DTBT-based polymers in high-voltage OSCs, herein, D18-Cl and PE55 are used to combine with a wide-bandgap non-fullerene acceptor (NFA), BTA3, and achieve ultrahigh VOC of 1.30 and 1.28 V, respectively. Compared with D18-Cl based on tricyclic benzodithiophene (BDT) segment, PE55 containing the pentacyclic dithienobenzodithiophene (DTBDT) unit possesses better hole mobility, higher charge-transfer efficiency, and more desirable phase separation. Hence, PE55:BTA3 blend exhibits a higher efficiency of 9.36% than that of D18-Cl: BTA3 combination (6.30%), which is one of the highest values for OSCs at ≈1.3 V VOC . This work attests that DTBT-based p-type polymers are ideal for the application in high-voltage OSCs.


Assuntos
Polímeros , Tiadiazóis
16.
Ecotoxicol Environ Saf ; 254: 114757, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36950987

RESUMO

Soil and water are increasingly at risk of contamination from the toxic heavy metals lead (Pb) and cadmium (Cd). Arabis paniculata (Brassicaceae) is a hyperaccumulator of heavy metals (HMs) found widely distributed in areas impacts by mining activities. However, the mechanism by which A. paniculata tolerates HMs is still uncharacterized. For this experiment, we employed RNA sequencing (RNA-seq) in order to find Cd (0.25 mM)- and Pb (2.50 mM)-coresponsive genes A. paniculata. In total, 4490 and 1804 differentially expressed genes (DEGs) were identified in root tissue, and 955 and 2209 DEGs were identified in shoot tissue, after Cd and Pb exposure, respectively. Interestingly in root tissue, gene expression corresponded similarly to both Cd and Pd exposure, of which 27.48% were co-upregulated and 41.00% were co-downregulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses showed that the co-regulated genes were predominantly involved in transcription factors (TFs), cell wall biosynthesis, metal transport, plant hormone signal transduction, and antioxidant enzyme activity. Many critical Pb/Cd-induced DEGs involved in phytohormone biosynthesis and signal transduction, HM transport, and transcription factors were also identified. Especially the gene ABCC9 was co-downregulated in root tissues but co-upregulated in shoot tissues. The co-downregulation of ABCC9 in the roots prevented Cd and Pb from entering the vacuole rather than the cytoplasm for transporting HMs to shoots. While in shoots, the ABCC9 co-upregulated results in vacuolar Cd and Pb accumulation, which may explain why A. paniculata is a hyperaccumulator. These results will help to reveal the molecular and physiological processes underlying tolerance to HM exposure in the hyperaccumulator A. paniculata, and aid in future efforts to utilize this plant in phytoremediation.


Assuntos
Arabis , Metais Pesados , Poluentes do Solo , Cádmio/metabolismo , Arabis/genética , Arabis/metabolismo , Chumbo/análise , Transcriptoma , Metais Pesados/análise , Biodegradação Ambiental , Reguladores de Crescimento de Plantas/metabolismo , Poluentes do Solo/análise , Raízes de Plantas/metabolismo
17.
J Mater Chem B ; 11(14): 3113-3123, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36947418

RESUMO

Nanotechnology is an effective way to stimulate the yield potential of crops. Various nano-fertilizers and nano-carriers are gradually being developed to bring about a technological revolution in the agricultural industry. As a biocompatible water-soluble nanomaterial, carbon dots (CDs) have attracted the attention of researchers for applications in agriculture. In this study, we prepared nitrogen-doped CDs (N-CDs) as a type of water-soluble carbon nanofertilizer by a one-pot hydrothermal method, and investigated its effects on lettuce biomass and quality. 100 and 200 mg L-1 of N-CDs substantially promoted lettuce biomass accumulation (41.70%), elevated lettuce nutrient content, as well as promoted the accumulation of major nutrients. Moreover, 100 mg L-1 N-CDs increased the chlorophyll a content by 12.68%, significantly increased the electron transport rate (ETR) by 38.61%, significantly increased the light energy conversion efficiency (Y(II)) by 31.24% and increased the Rubisco activity by 60.61%, which are important reasons for its increase in actual photosynthesis rate. N-CDs also have a positive effect on plant nitrogen metabolism by promoting the activity of glutamine synthetase. The significant benefits of N-CDs on lettuce make them have great potential for agricultural yield increase and quality improvement.


Assuntos
Pontos Quânticos , Nitrogênio , Carbono , Clorofila A , Água
18.
Small ; 19(31): e2206222, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36907994

RESUMO

Optimizing photosynthesis is imperative for providing energy and organics for all life on the earth. Here, carbon dots doped with pyridinic nitrogen (named lev-CDs) are synthesized by the one-pot hydrothermal method, and the structure-function relationship between functional groups on lev-CDs and photosynthesis of Chlorella pyrenoidosa (C. pyrenoidosa) is proposed. Pyridinic nitrogen plays a key role in the positive effect on photosynthesis caused by lev-CDs. In detail, lev-CDs act as electron donors to supply photo-induced electrons to P680+ and QA+ , causing electron transfer from lev-CDs to the photosynthetic electron transport chain in the photosystems. In return, the recombination efficiency of electron-hole pairs on lev-CDs decreases. As a result, the electron transfer rate in the electron transport chain, the activity of photosystem II, and the Calvin cycle are enhanced. Moreover, the electron transfer rate between C. pyrenoidosa and external circumstances enhanced by lev-CDs is about 50%, and electrons exported from C. pyrenoidosa can be used to reduce iron(III). This study is of great significance for engineering nanomaterials to improve photosynthesis.


Assuntos
Chlorella , Pontos Quânticos , Transporte de Elétrons , Elétrons , Carbono/farmacologia , Nitrogênio , Compostos Férricos/farmacologia , Fotossíntese
19.
Front Psychol ; 14: 1049266, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36760436

RESUMO

Argument mining (AM), an emerging field in natural language processing (NLP), aims to automatically extract arguments and the relationships between them in texts. In this study, we propose a new method for argument mining of argumentative essays. The method generates dynamic word vectors with BERT (Bidirectional Encoder Representations from Transformers), encodes argumentative essays, and obtains word-level and essay-level features with BiLSTM (Bi-directional Long Short-Term Memory) and attention training, respectively. By integrating these two levels of features we obtain the full-text features so that the content in the essay is annotated according to Toulmin's argument model. The proposed method was tested on a corpus of 180 argumentative essays, and the precision of automatic annotation reached 69%. The experimental results show that our model outperforms existing models in argument mining. The model can provide technical support for the automatic scoring system, particularly on the evaluation of the content of argumentative essays.

20.
Protein Sci ; 32(4): e4590, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36764820

RESUMO

Photoreceptors containing the light-oxygen-voltage (LOV) domain elicit biological responses upon excitation of their flavin mononucleotide (FMN) chromophore by blue light. The mechanism and kinetics of dark-state recovery are not well understood. Here we incorporated the non-canonical amino acid p-cyanophenylalanine (CNF) by genetic code expansion technology at 45 positions of the bacterial transcription factor EL222. Screening of light-induced changes in infrared (IR) absorption frequency, electric field and hydration of the nitrile groups identified residues CNF31 and CNF35 as reporters of monomer/oligomer and caged/decaged equilibria, respectively. Time-resolved multi-probe UV/visible and IR spectroscopy experiments of the lit-to-dark transition revealed four dynamical events. Predominantly, rearrangements around the A'α helix interface (CNF31 and CNF35) precede FMN-cysteinyl adduct scission, folding of α-helices (amide bands), and relaxation of residue CNF151. This study illustrates the importance of characterizing all parts of a protein and suggests a key role for the N-terminal A'α extension of the LOV domain in controlling EL222 photocycle length.


Assuntos
Aminoácidos , Mononucleotídeo de Flavina , Aminoácidos/metabolismo , Mononucleotídeo de Flavina/química , Fatores de Transcrição/metabolismo , Regulação da Expressão Gênica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...