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1.
Theor Appl Genet ; 137(6): 137, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38769163

RESUMEN

KEY MESSAGE: We identified a SbPLSH1gene conferring purple leaf sheath in sorghum (sorghumbicolor(L.) Moench)and developed a functional markerfor it. The purple leaf sheath of sorghum, a trait mostly related to anthocyanin deposition, is a visually distinguishable morphological marker widely used to evaluate the purity of crop hybrids. We aimed to dissect the genetic mechanism for leaf sheath color to mine the genes regulating this trait. In this study, two F2 populations were constructed by crossing a purple leaf sheath inbred line (Gaoliangzhe) with two green leaf sheath inbred lines (BTx623 and Silimei). Based on the results of bulked-segregant analysis sequencing, bulk-segregant RNA sequencing, and map-based cloning, SbPLSH1 (Sobic.006G175700), which encodes a bHLH transcription factor on chromosome 6, was identified as the candidate gene for purple leaf sheath in sorghum. Genetic analysis demonstrated that overexpression of SbPLSH1 in Arabidopsis resulted in anthocyanin deposition and purple petiole, while two single-nucleotide polymorphism (SNP) variants on the exon 6 resulted in loss of function. Further haplotype analysis revealed that there were two missense mutations and one cis-acting element mutation in SbPLSH1, which are closely associated with leaf sheath color in sorghum. Based on the variations, a functional marker (LSC4-2) for marker-assisted selection was developed, which has a broad-spectrum capability of distinguishing leaf sheath color in natural variants. In summary, this study lays a foundation for analyzing the genetic mechanism for sorghum leaf sheath color.


Asunto(s)
Antocianinas , Hojas de la Planta , Polimorfismo de Nucleótido Simple , Sorghum , Sorghum/genética , Sorghum/crecimiento & desarrollo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Antocianinas/metabolismo , Marcadores Genéticos , Fenotipo , Pigmentación/genética , Mapeo Cromosómico , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Genes de Plantas , Plantas Modificadas Genéticamente/genética , Haplotipos , Regulación de la Expresión Génica de las Plantas
2.
Phys Chem Chem Phys ; 24(23): 14545-14551, 2022 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-35666149

RESUMEN

Localized surface plasmon resonance (LSPR) is caused by the irradiation of light on a metal surface. Here we present a surface plasmon catalytic reaction at the gas-liquid-solid three phase interface. Electrochemical deposition was used to prepare Ag nanostructure/Cu mesh surface-enhanced Raman scattering (SERS) substrates. Surface wettability was adjusted by changing the processing time of the surfactant. Then a three-phase interface platform was constructed with good SERS performance and active surface plasmon catalytic capacity by droplet detection. At the gas-liquid-solid three phase interface, different oxygen supplies for the catalytic reaction were offered on surfaces with different wettability values. Thus, in this study, surface plasmon catalytic reaction of p-nitroaniline (PNA) was successfully in situ monitored and the reaction mechanism was explored. Otherwise, density functional theory (DFT) was used to calculate the Raman spectra and energy levels of the reactants and reaction products. Moreover, this work provides a new platform for monitoring the surface plasmon reaction at the gas-liquid-solid three-phase interface and contributes to the development of the study in the surface plasmon catalytic reaction field.

3.
Nanotechnology ; 32(42)2021 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-34256363

RESUMEN

Accurately detect the residues of organophosphate pesticides (OPs) in food and environment is critical to our daily lives. In this study, we developed a novel acetylcholinesterase (AChE) biosensor based on Au-Tb alloy nanospheres (NSs) for rapid and sensitive detection of OPs for the first time. Au-Tb alloy NSs that with good conductivity and biocompatibility were produced with a mild hydrothermal. Under optimal conditions, the AChE biosensor was obtained by a simple assembly process, with a big linear range (10-13-10-7M) and the limit of detection was 2.51 × 10-14M for the determination of methyl parathion. Moreover, the determination of methyl parathion with the prepared biosensor presented a high sensitivity, outstanding repeatability and superior stability compared with other reported biosensors. Through the determination of tap water and Yanming lake samples, it was proved that the modified biosensor with satisfactory recoveries (96.76%-108.6%), and are realizable in the determination of OPs in real samples.


Asunto(s)
Acetilcolinesterasa , Técnicas Biosensibles/métodos , Enzimas Inmovilizadas , Compuestos Organofosforados/análisis , Plaguicidas/análisis , Acetilcolinesterasa/química , Acetilcolinesterasa/metabolismo , Aleaciones/química , Técnicas Electroquímicas , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Oro/química , Terbio/química , Contaminantes Químicos del Agua/análisis
4.
Anal Bioanal Chem ; 412(5): 1159-1167, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31872273

RESUMEN

We report a method for preparing flexible substrates based on 3D Ag nanodendrites (Ag NDs)/carbon fiber cloth substrate with superhydrophobic surface. Ag NDs were deposited on carbon fiber cloth by electrochemical deposition, and the superhydrophobicity of the surface was achieved by low surface energy modification. The cylinder shape of the carbon fiber provides a three-dimensional structure for Ag NDs, increasing the "hot spot" effect, and is the excellent choice as SERS substrate. At the same time, micro/nanostructures provided by fibers and nanodendrites can easily obtain ultra-wet surfaces. The analyte solution can be directly detected in a droplet onto the superhydrophobic surface without pretreatment, which greatly shortens the detection time. The lowest concentration of crystal violet (CV) that can be detected is 10-10 M, demonstrating good SERS sensitivity of the prepared substrate. It was successfully applied in simultaneous detection of at least three molecules. Thiram and malachite green (MG) can be detected simultaneously in real lake water. Moreover, the conductivity, physical flexibility, and stability of the flexible carbon fiber cloth gives this substrate potential in other fields such as electrochemistry. Graphical abstract Flexible SERS substrate based on Ag nanodendrite-coated carbon fiber cloth: simultaneous detection for multiple pesticides in liquid droplet.

5.
Mikrochim Acta ; 187(6): 349, 2020 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-32462256

RESUMEN

A peptide (Li5-025)-modified gold nanoparticle (AuNP)/(titania (TiO2) + 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphine (TAPP))/glassy carbon electrode (GCE) was developed for lipopolysaccharide (LPS) determination. This electrode not only performs well in the electrochemical impedance determination of LPS in serum but can also be easily regenerated under light irradiation. Using Fe(CN)63-/4- as a redox probe, LPS recognition can be indicated by the significantly increased electron-transfer resistance (Ret) as a result of the coaction of the increased steric hindrance from the peptide-LPS complex and the electrostatic repulsion between LPS and Fe(CN)63-/4-. The impedimetric signal was acquired in the frequency range 0.1 Hz ~ 100 kHz with an initial voltage of 174 mV and an amplitude of 10 mV. The resistance changes (ΔRet) are linearly related to the LPS concentrations in a broad range (0.1 pg mL-1 ~ 100 ng mL-1) with a low detection limit (0.08 pg mL-1). Importantly, the electrode shows high selectivity to LPS from Escherichia coli O55:B5 compared to other bacterial sources and considerable anti-interference to 0.1% fetal calf serum, demonstrating its potential application in clinically relevant samples. Another highlight is that the AuNP/(TiO2 + TAPP)/GCE surface can be photocatalytically regenerated under light irradiation (50 mW cm-2, 300-2500 nm) without any obvious damage to the electrode microstructure. After simple peptide re-immobilization, the regenerated electrode demonstrates LPS response similar to the peptide less one, and the deviation is only 2.89% after 5-cycle reuse. Graphical abstract A peptide (Li5-025)-modified AuNP/(TiO2 + TAPP porphine)/GCE was proposed, which not only has excellent electrochemical analytical performances for LPS assay in serum but also can be reused after light irradiation and subsequent peptide re-immobilization.


Asunto(s)
Proteínas Inmovilizadas/química , Lipopolisacáridos/sangre , Péptidos/química , Secuencia de Aminoácidos , Animales , Carbono/química , Catálisis/efectos de la radiación , Bovinos , Espectroscopía Dieléctrica/instrumentación , Espectroscopía Dieléctrica/métodos , Electrodos , Escherichia coli/química , Oro/química , Oro/efectos de la radiación , Luz , Límite de Detección , Nanopartículas del Metal/química , Nanopartículas del Metal/efectos de la radiación , Porfirinas/química , Porfirinas/efectos de la radiación , Titanio/química , Titanio/efectos de la radiación
6.
Langmuir ; 35(13): 4626-4633, 2019 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-30892046

RESUMEN

The present study demonstrated a one-step method for the first time to fabricate self-assembled gold nanoparticle (AuNP) metafilms at the water-toluene interface by adding polystyrene-polyisoprene-polystyrene as the support layer. The thiolated polyethylene glycol and ethanol were used to tune the surface charge density on the AuNPs, constructing a balanced situation at the water-toluene interface. The flexible (AuNP) metafilm can be easily obtained after evaporation of the toluene phase and further used as a surface-enhanced Raman scattering (SERS) substrate for trace thiram detection. The SERS sensitivity was tested using standard Raman probes such as crystal violet and malachite green, both with the detect concentration reaching 1 × 10-11 M. Moreover, the excellent reproducibility and elastic properties make the metafilm promising in practical detection. Hence, the trace thiram detection on an orange pericarp was inspected with the detection limit of 0.5 ppm (1 × 10-6 M) as well as a favorable linearity relation with a correlation coefficient of 0.979, exactly matching the realistic application requirements.

7.
Inorg Chem ; 58(8): 4859-4868, 2019 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-30931557

RESUMEN

To understand Raman spectra shifts of nanocrystals, the top-down phonon confinement approach and the bottom-up quantum chemical approach were developed. The former is suitable for large-sized nanocrystals, and the latter is suitable for clusters containing fewer atoms. Here, we find that a simpler chemical bond model based on the bond dispersion feature can demonstrate Raman spectra shift either in normal size II-VI semiconductor nanocrystals or in atomically precise clusters. According to the bond dispersion model, the Raman spectral line of the II-VI semiconductor nanocrystal (AIIBVI) is expressed as the sum of the Lorentz subpeaks of the AII( i)BVI( j) bonds with different coordinates i and j. The calculated Raman lines of CdSe, CdS, CdTe, ZnS, and ZnSe nanocrystals are in agreement with the measured Raman spectral lines. The origin of the red shift and asymmetric broadening of the peak position of nanocrystals may be revealed as well. Results provide insight into how different bonds contribute to different vibrational spectra.

8.
Mikrochim Acta ; 185(2): 90, 2018 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-29594421

RESUMEN

The authors describe a rapid and direct SERS-based immunoassay for the determination of AFP, an important marker for diagnosis of hepatocellular carcinoma. Silver nanoparticles (AgNPs; 36 nm i.d.) serve as a support to immobilize antibody and as a SERS intensifier, and AFP-modified gold nanoparticles are employed as capturing substrate. Direct and quantitative detection of AFP is accomplished with a limit detection as low as 5 ng·mL-1. Compared to assays based on the use of metal nanoparticles, the use of gold-silver nanoparticle heterodimers as an active SERS substrate can save costs because only a single antibody is required. Moreover, the high selectivity and good linear relationship of detecting AFP in fetal bovine serum indicates its potential applicability for the direct analysis of clinical samples. Graphical abstract Direct and quantitative determination of AFP antigen utilizing SERS has been was successfully presented and applied to detect alpha fetoprotein antigen in fetal bovine serum with detection limit of 2 ng•mL-1.

9.
BMC Microbiol ; 14: 322, 2014 Dec 24.
Artículo en Inglés | MEDLINE | ID: mdl-25539737

RESUMEN

BACKGROUND: Motility of flagellated bacteria depends crucially on their organelles such as flagella and pili, as well as physical properties of the external medium, such as viscosity and matrix elasticity. We studied the motility of wild-type and two mutant strains of Caulobacter crescentus swarmer cells in two different types of media: a viscous and hyperosmotic glycerol-growth medium mixture and a viscoelastic growth medium, containing polyethylene glycol or polyethylene oxide of different defined sizes. RESULTS: For all three strains in the medium containing glycerol, we found linear drops in percentage of motile cells and decreases in speed of those that remained motile to be inversely proportional to viscosity. The majority of immobilized cells lost viability, evidenced by their membrane leakage. In the viscoelastic media, we found less loss of motility and attenuated decrease of swimming speed at shear viscosity values comparable to the viscous medium. In both types of media, we found more severe loss in percentage of motile cells of wild-type than the mutants without pili, indicating that the interference of pili with flagellated motility is aggravated by increased viscosity. However, we found no difference in swimming speed among all three strains under all test conditions for the cells that remained motile. Finally, the viscoelastic medium caused no significant change in intervals between flagellar motor switches unless the motor stalled. CONCLUSION: Hyperosmotic effect causes loss of motility and cell death. Addition of polymers into the cell medium also causes loss of motility due to increased shear viscosity, but the majority of immobilized bacteria remain viable. Both viscous and viscoelastic media alter the motility of flagellated bacteria without affecting the internal regulation of their motor switching behavior.


Asunto(s)
Caulobacter crescentus/fisiología , Medios de Cultivo/química , Elasticidad , Locomoción , Viscosidad , Viabilidad Microbiana , Presión Osmótica
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 309: 123834, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38198990

RESUMEN

Local surface plasmon resonance (LSPR) is a novel catalytic technique that has emerged in recent years, especially in the catalysis of aromatic amine compounds. However, the response process and mechanism are still unclear in current study. In the current field of study, the response process and mechanism are still unclear. In this work, the gas-liquid-solid three-phase interface (GLSTI) was innovatively utilized in this study to validate the reaction mechanism by surface-enhanced Raman spectroscopy. P-Aminothiophenol (PATP) and P-Phenylenediamine (PDA) underwent a surface plasmon-catalyzed reaction by using a silver nano-dendrites substrate with strong SERS activity. The GLSTI significantly facilitates the occurrence of surface plasmon catalytic reactions, which can supply enough oxygen by providing three-phase points. In situ SERS and EC-SERS technologies were combined in this study for the explorations. Therefore, this work is dedicated to deepening the exploration and expanding into new directions in plasmon-induced catalytic reactions.

11.
Clin Imaging ; 103: 109979, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37673705

RESUMEN

PURPOSE: The purpose of this study is to determine upgrade rates of lobular neoplasia detected by screening digital breast tomosynthesis (DBT) and to determine imaging and clinicopathological features that may influence risk of upgrade. METHODS: Medical records were reviewed of consecutive women who presented with screening DBT-detected atypical lobular hyperplasia (ALH) and/or lobular carcinoma in situ (LCIS) from January 1, 2013, to June 30, 2020. Included patients underwent needle biopsy and had surgery or at least two-year imaging follow-up. Imaging and clinicopathological features were compared between upgraded and nonupgraded cases of lobular neoplasia using the Pearson's chi-squared test and the Wilcoxon signed-rank test. RESULTS: During the study period, 107 women (mean age 55 years, range 40-88 years) with 110 cases of ALH and/or LCIS underwent surgery (80.9%, n = 89) or at least two-year imaging follow-up (19.1%, n = 21). The overall upgrade rate to cancer was 5.5% (6/110), and the upgrade rate to invasive cancer was 3.6% (4/110). The upgrade rate of ALH to cancer was 4.1% (3/74), whereas the upgrade rate of LCIS to cancer was 9.4% (3/32) (p = .28). The upgrade rate of cases presenting as calcifications was 4.2% (3/71), whereas the upgrade rates of cases presenting as noncalcified findings was 7.7% (3/39) (p = .44). CONCLUSIONS: The upgrade rate of screening DBT-detected lobular neoplasia is less than 6%. Surveillance rather than surgery can be considered for lobular neoplasia, particularly in patients with ALH and in those with screening-detected calcifications leading to the diagnosis.


Asunto(s)
Carcinoma de Mama in situ , Neoplasias de la Mama , Calcinosis , Carcinoma in Situ , Carcinoma Lobular , Lesiones Precancerosas , Femenino , Humanos , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Carcinoma Lobular/diagnóstico por imagen , Carcinoma Lobular/patología , Carcinoma in Situ/diagnóstico , Carcinoma in Situ/patología , Carcinoma in Situ/cirugía , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/epidemiología , Mama/patología , Lesiones Precancerosas/diagnóstico por imagen , Lesiones Precancerosas/patología , Carcinoma de Mama in situ/diagnóstico por imagen , Carcinoma de Mama in situ/patología , Hiperplasia/patología , Biopsia con Aguja Gruesa
12.
Front Plant Sci ; 14: 1141617, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37008506

RESUMEN

Plant U-box (PUB) E3 ubiquitin ligases play essential roles in many biological processes and stress responses, but little is known about their functions in sorghum (Sorghum bicolor L.). In the present study, 59 SbPUB genes were identified in the sorghum genome. Based on the phylogenetic analysis, the 59 SbPUB genes were clustered into five groups, which were also supported by the conserved motifs and structures of these genes. SbPUB genes were found to be unevenly distributed on the 10 chromosomes of sorghum. Most PUB genes (16) were found on chromosome 4, but there were no PUB genes on chromosome 5. Analysis of cis-acting elements showed that SbPUB genes were involved in many important biological processes, particularly in response to salt stress. From proteomic and transcriptomic data, we found that several SbPUB genes had diverse expressions under different salt treatments. To verify the expression of SbPUBs, qRT-PCR analyses also were conducted under salt stress, and the result was consistent with the expression analysis. Furthermore, 12 SbPUB genes were found to contain MYB-related elements, which are important regulators of flavonoid biosynthesis. These results, which were consistent with our previous multi-omics analysis of sorghum salt stress, laid a solid foundation for further mechanistic study of salt tolerance in sorghum. Our study showed that PUB genes play a crucial role in regulating salt stress, and might serve as promising targets for the breeding of salt-tolerant sorghum in the future.

13.
ACS Omega ; 8(7): 7102-7110, 2023 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-36844519

RESUMEN

In order to study the change laws of free radicals and functional groups during low-temperature coal oxidation, three coal samples with different metamorphic degrees were selected for ESR and FTIR analysis. The results showed that the concentration of free radicals increased as the temperature increased; meanwhile, the types of free radicals changed constantly, and the free radical variation range decreased with the increase in coal metamorphism. The side chains of aliphatic hydrocarbons in coal with a low metamorphic degree decreased by varying amounts in the initial heating stage. The -OH content of bituminous coal and lignite increased first and then decreased, while that in anthracite decreased first and then increased. In the initial oxidation stage, -COOH first increased rapidly, then decreased rapidly, and then increased before finally decreasing. The content of -C=O in bituminous coal and lignite increased in the initial stage of oxidation. Through gray relational analysis, it was found that there was a significant relationship between free radicals and functional groups, and -OH had the strongest correlation with free radicals. This paper provides a theoretical basis for studying the mechanism of functional groups transforming into free radicals in the process of coal spontaneous combustion.

14.
Front Chem ; 11: 1165402, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37082230

RESUMEN

Using municipal and industrial solid waste as a substitute raw material and fuel in cement rotary kiln co-processing is considered an economic and environmentally friendly alternative to the use of traditional fuels. However, the presence of heavy metals in solid waste is a growing concern in the cement rotary kiln co-processing technique. The solidification mechanism of heavy metals in cement clinker is directly related to their stabilization. Cement clinkers doped with manganese oxide (MnO2: 0.0%-5.0% wt%) were prepared in a laboratory to investigate the impacts of extrinsic Mn on cement clinker calcination. The insignificant changes in X-ray diffractometer patterns indicated that the fixed Mn had little influence on the mineral lattice structure. Raman spectra and X-ray photoelectron spectroscopy revealed the transformation of the silicate phase when the Mn dose was increased. Moreover, the satisfactory solidification ratio confirmed the incorporation of Mn in the cement clinker. These results provided evidence of the influence rule of Mn in the cement clinker calcination process. Furthermore, Raman spectroscopy showed great potential for the qualitative and semi-quantitative analysis of the cementitious materials derived from cement rotary kiln co-processing. These results will be important for the further development of green cement manufacturing technology.

15.
Spectrochim Acta A Mol Biomol Spectrosc ; 302: 123082, 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-37413919

RESUMEN

Antioxidants play an important role in life health and food safety. Herein, an inverse-etching platform based on gold nanorods (AuNRs) and gold nanostars (AuNSs) for high-throughput discrimination of antioxidants was constructed. Under the action of hydrogen peroxide (H2O2) and horseradish peroxidase (HRP), 3,3',5,5'-tetramethylbenzidine (TMB) would be oxidized to TMB+ or TMB2+. HRP reacts with H2O2 to release oxygen free radicals, which then react with TMB. Au nanomaterials can react with TMB2+, at the same time, Au was oxidized into Au (I), leading to the etching of the shape. Antioxidants, with good reduction ability, would prevent the further oxidation of TMB+ to TMB2+. So the presence of antioxidants will prevent further oxidation while avoiding the etching of Au in the catalytic oxidation process, thereby achieved inverse etching. Distinctive surface enhanced Raman scattering (SERS) fingerprint of five antioxidants were obtained based on the differential ability to scavenge free radicals. Five antioxidants, including ascorbic acid (AA), melatonin (Mel), glutathione (GSH), tea polyphenols (TPP), and uric acid (UA) were successfully distinguished by using linear discriminant analysis (LDA), heat map analysis and hierarchical cluster analysis (HCA). The study exhibits an effective inverse-etching based SERS sensor array for the response of antioxidants, which has great reference value in the field of human disease and food detection.


Asunto(s)
Técnicas Biosensibles , Nanopartículas del Metal , Humanos , Antioxidantes/análisis , Peróxido de Hidrógeno , Ácido Ascórbico/análisis , Oro , Glutatión/análisis , Peroxidasa de Rábano Silvestre , Colorimetría
16.
Artículo en Inglés | MEDLINE | ID: mdl-36759344

RESUMEN

Due to the advantages of low cost and good thermal stability, all-inorganic CsPbI2Br carbon-based perovskite solar cells (C-PSCs) without a hole transport layer have been rapidly developed in recent years. While the carbon electrode is in direct contact with the CsPbI2Br film, higher requirements are placed on the defects and energy level arrangement of the CsPbI2Br layer, which leads to the relatively low photoelectric conversion efficiency (PCE) of C-PSCs. Herein, propylamine hydrobromide (PABr) and its derivative 3-bromopropylamine hydrobromide (3Br-PABr) were used to passivate the surface defects of CsPbI2Br C-PSCs for the first time. The results show that passivation molecules are modulated by the substituent effect, leading to a stronger interaction between amino groups and uncoordinated Pb2+ ions, which facilitates a better passivation effect of 3Br-PABr. In addition, 3Br-PABr promotes the gradient arrangement of energy levels while passivating surface defects, which accelerates the rapid extraction of holes. After the passivation by PABr and 3Br-PABr, the PCE of HTL-free CsPbI2Br C-PSCs increased from 12.15% for the control device to 13.15 and 14.04%, respectively, which are among the highest reported values of CsPbI2Br C-PSCs.

17.
Small Methods ; 7(7): e2300192, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37116089

RESUMEN

In order to improve the thermal stability of perovskite solar cells (PSCs) and reduce production costs, hole transport layer (HTL)-free carbon-based CsPbI3 PSCs (C-PSCs) have attracted the attention of researchers. However, the power conversion efficiency (PCE) of HTL-free CsPbI3 C-PSCs is still lower than that of PSCs with HTL/ metal electrodes. This is because the direct contact between the carbon electrode and the perovskite layer has a higher requirement on the crystal quality of perovskite layer and matched energy level at perovskite/carbon interface. Herein, the acyl chloride group and its derivative trichloroacetyl chloride are used to passivate CsPbI3 C-PSCs for the first time. The results show that the carbonyl group of trichloroacetyl chloride can effectively passivate the uncoordinated Pb2+ ions in perovskite. At the same time, leaving group Cl- ions can increase the grain size of perovskite and improve the crystallization quality of perovskite layer. In addition, the trichloroacetyl chloride tends to generate cesium chloride acetate, which acts as an electron blocking layer, reduces charge recombination, promotes gradient energy level arrangement, and effectively improves the separation and extraction ability of carriers. The PCE of CsPbI3 HTL-free C-PSCs is successfully increased from 13.40% to 14.82%.

18.
Travel Behav Soc ; 28: 181-195, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35402163

RESUMEN

It is widely reported that the COVID-19 pandemic has reduced ridership and brought severe challenges to urban public transit systems in many countries. The impact of the COVID-19 pandemic on individual people's choice of public transit may continue for a while after the peak of the crisis. However, there is insufficient detailed knowledge of how individuals respond in the post-pandemic context and make choices on public transit travel. This paper contributes fresh evidence for this by looking at Beijing as a case. The theoretical framework of the Theory of Planned Behavior is used to model individuals' public transit travel choice-making processes along with three additional constructs representing the impact of the pandemic and the nature of urban mobility behaviors, namely perceived knowledge of COVID-19, the psychological risks of COVID-19, and travel habits. Structural equation modeling is used in model estimation. We point out that there may be potential differences between the effects and meanings of model constructs in the post-pandemic context and in normal daily context. Interestingly, despite the higher psychological risk's negative effects, higher perceived knowledge of COVID-19 has significantly positive effects on people's decision-making processes. A strong pre-pandemic personal habit of traveling by public transit has significant and positive effects on post-pandemic intention and perceived behavioral control. Group comparisons show that "captive" transit users have higher psychological risk of COVID-19 than "choice" transit users, yet their transit use decisions are less influenced by it. Based on the modeling results, more behavioral experiments are needed to further inform efficient policy-making.

19.
Micromachines (Basel) ; 13(12)2022 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-36557394

RESUMEN

The Mask R-CNN-based object detection method is typically very time-consuming and laborious since it involves obtaining the required target object masks during training. Therefore, in order to automatically generate the image mask, we propose a GrabCut-based automated mask generation method for object detection. The proposed method consists of two stages. The first stage is based on GrabCut's interactive image segmentation method to generate the mask. The second stage is based on the object detection network of Mask R-CNN, which uses the mask from the previous stage together with the original input image and the associated label information for training. The Mask R-CNN model then automatically detects the relevant objects during testing. During experimentation with three objects from the Berkeley Instance Recognition Dataset, this method achieved a mean of average precision (mAP) value of over 95% for segmentation. The proposed method is simple and highly efficient in obtaining the mask of a segmented target object.

20.
ACS Omega ; 7(20): 17202-17214, 2022 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-35647455

RESUMEN

Considering disadvantages such as the low thermal stability and environmental pollution of existing gel inhibitors, a green and stable intumescent nanoinhibitor (INI) was prepared and tested. First, polyacrylamide (PAM), nano-silica, and intumescent flame retardant (IFR) were selected as raw materials. The INI was prepared by nanoparticle modification and cross-linking polymerization. Then, the structure and physical properties of INI were tested by Fourier transform infrared spectroscopy, scanning electron microscopy, and rheological experiments. Meanwhile, the inhibition performance of INI was studied through thermogravimetric analysis-Fourier transfer infrared spectroscopy (TGA-FTIR) analysis. The results suggest that the nanomodification improved the dispersibility of INI particles. The addition of modified nano-silica (MNS) and IFR enhances the strength of the reticular structure, thereby improving the transport convenience and covering ability of the INI gel. At high temperatures, IFR can generate a porous foamed carbon layer that further coats the coal. After INI inhibition treatment, the characteristic temperature and activation energy of coal were significantly improved, and the production of carbon monoxide and carbon dioxide decreased. Hence, irrespective of physical properties, physical inhibition performance, or chemical inhibition performance, INI performed well. Research results can provide valuable references for the preparation and performance study of a coal spontaneous combustion inhibitor.

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