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1.
J Virol ; 96(9): e0037322, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35404081

RESUMO

M2 protein of influenza virus plays an important role in virus budding, including membrane scission and vRNP packaging. Three hydrophobic amino acids (91F, 92V, and 94I) at the intracellular domain of the M2 protein constitute a hydrophobic motif, also known as the LC3-interacting region (LIR), whereas the role of this motif remains largely unclear. To explore the role of the 91-94 hydrophobic motif for influenza virus, all three hydrophobic amino acids were mutated to either hydrophilic S or hydrophobic A, resulting in two mutant viruses (WSN-M2/SSS and WSN-M2/AAA) in the background of WSN/H1N1. The results showed that the budding ability of the M2/SSS protein was inhibited and the bilayer membrane integrity of the WSN-M2/SSS virion was impaired based on transmission electron microscopy (TEM), which in turn abolished the resistance to trypsin treatment. Moreover, the mutant WSN-M2/SSS was dramatically attenuated in mice. In contrast, the AAA mutations did not have a significant effect on the budding of the M2 proteins or the bilayer membrane integrity of the viruses, and the mutant WSN-M2/AAA was still lethal to mice. In addition, although the 91-94 motif is an LIR, knocking out of the LC3 protein of A549 cells did not significantly affect the membrane integrity of the influenza viruses propagated on the LC3KO cells, which suggested that the 91-94 hydrophobic motif affected the viral membrane integrity and budding is independent of the LC3 protein. Overall, the hydrophobicity of the 91-94 motif is crucial for the budding of M2, bilayer membrane integrity, and pathogenicity of the influenza viruses. IMPORTANCE M2 plays a crucial role in the influenza virus life cycle. However, the function of the C-terminal intracellular domain of M2 protein remains largely unclear. In this study, we explored the function of the 91-94 hydrophobic motif of M2 protein. The results showed that the reduction of the hydrophobicity of the 91-94 motif significantly affected the budding ability of the M2 protein and impaired the bilayer membrane integrity of the mutant virus. The mouse study showed that the reduction of the hydrophobicity of the 91-94 motif significantly attenuated the mutant virus. All of the results indicated that the hydrophobicity of the 91-94 motif of the M2 protein plays an important role in budding, membrane integrity, and pathogenicity of influenza virus. Our study offers insights into the mechanism of influenza virus morphogenesis, particularly into the roles of the 91-94 hydrophobic motif of M2 in virion assembly and the pathogenicity of the influenza viruses.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Proteínas da Matriz Viral , Proteínas Viroporinas , Liberação de Vírus , Aminoácidos/metabolismo , Animais , Interações Hidrofóbicas e Hidrofílicas , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/fisiologia , Camundongos , Proteínas da Matriz Viral/metabolismo , Proteínas Viroporinas/metabolismo
2.
Phys Chem Chem Phys ; 25(31): 20843-20853, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37503681

RESUMO

Gold nanorods have been widely used in various fields due to their tunable anisotropic localized surface plasmon resonance (SPR) property. The facile preparation of gold nanorods with a tunable SPR wavelength extending to a near-infrared window, and at the same time, a relatively small particle size for facilitating applications especially in the biomedical field is of great value yet highly challenging. In this work, a new reducing agent, 1,6-dihydroxynaphthalene, is proposed for the synthesis of gold nanorods. The results indicate that gold nanorods with good monodispersity, high shape yield, maximum SPR wavelength of 1200 nm, and especially small diameter of around 10 nm can be acquired simultaneously. In terms of spectral and size controls, by respectively varying the experimental parameters including the amount of silver ions, reducing agents, and gold seeds not only can a good linear correlation be acquired corresponding to a SPR wavelength ranging from around 600 nm to 1200 nm, but a regular change in the particle diameter from 10.5 nm to 7.5 nm could also be observed. The structural and morphological evolutions of the particle for each changed parameter were carefully studied, and insights were gained into the growth mechanism based on the detailed analysis of particle evolution at a specific stage of the growth process.

3.
Clin Exp Rheumatol ; 40(12): 2373-2380, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36441650

RESUMO

OBJECTIVES: To study the clinical characteristics of primary Sjögren's syndrome (pSS) with different onset age, and perform a review of the literature to confirm if the clinical phenotypes are affected by onset age in patients with pSS. METHODS: Data of 742 patients with pSS were retrospectively analysed. Patients were divided into three groups according to onset age: young-onset pSS (YopSS, <35 years), adult-onset pSS (AopSS, ≥35 and ≤65 years), and elderly-onset pSS (EopSS, >65 years). Clinical characteristics were compared among three groups and further multiple comparisons were conducted by Bonferroni adjustment. The Chi-squared test for linear-by-linear association was used to explore variation tendency. RESULTS: This study included 105 (14.2%), 533 (71.8%), and 104 (14.0%) cases of YopSS, AopSS, and EopSS, respectively. YopSS demonstrated lower prevalence of dry mouth, abnormal Schirmer I tests, and interstitial lung disease (ILD), but higher proportions of low C3 and C4 levels, and ANA, anti-SSA, anti-SSB, and rheumatoid factor (RF) positivity than AopSS and EopSS. The proportions of dry mouth (p=0.004), abnormal Schirmer I tests (p=0.002), and ILD (p<0.001) tended to increase with the increase of onset age, while the prevalence of leukopenia (p=0.011), low C3 (p=0.001), low C4 (p=0.001), and ANA (p<0.001), anti-SSA (p<0.001), anti-SSB (p<0.001) and RF (p<0.001) positivity tended to decrease with an increase in onset age. CONCLUSIONS: YopSS demonstrated less dryness and ILD, but more immunologic disorders. ILD prevalence were directly proportional to onset age of pSS; however, leukopenia, hypocomplementaemia, and autoantibody positivity showed opposite trends.


Assuntos
Doenças Pulmonares Intersticiais , Síndrome de Sjogren , Humanos , Estudos Retrospectivos , Síndrome de Sjogren/diagnóstico , Síndrome de Sjogren/epidemiologia , Idade de Início , Doenças Pulmonares Intersticiais/diagnóstico , Doenças Pulmonares Intersticiais/epidemiologia , Fator Reumatoide , Fenótipo
4.
Nanotechnology ; 34(5)2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36322962

RESUMO

The perovskite film prepared by the two-step spin coating method is widely used in photovoltaic devices due to its good film morphology and great reproducibility. However, there usually exists excessive lead iodide (PbI2) in the perovskite film for this method, which is believed to passivate the grain boundaries (GBs) to increase the efficiency of the perovskite solar cells. Nevertheless, the excessive PbI2at the GBs of perovskite is believed to induce the decomposition of the perovskite film and undermine the long-term stability of devices. In this study, we utilize precursor engineering to realize the preparation of perovskite solar cells with high efficiency and stability. The concentration of organic salts (AX: A = MA+, FA+; X = I-, Cl-) in the precursor solution for the second step of the two-step spin coating method is adjusted to optimize the perovskite light-absorbing layer so that the excessive PbI2is converted into perovskite to obtain a smooth and pinhole-free perovskite film with high performance. Our results indicate that by adjusting the concentration of AX in the precursor solution, PbI2in the film could be completely converted into perovskite without excessive AX residue. Both the efficiency and stability of the perovskite solar cells without excessive PbI2have been significantly improved. A planar perovskite solar cell with the highest power conversion efficiency (PCE) of 21.26% was achieved, maintaining about 90% of the initial PCE after 300 h of storage in a dry air environment and in the dark, about 76% of the initial PCE after 300 h of continuous illumination of 1 Sun.

5.
Rheumatol Int ; 42(12): 2221-2229, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35536378

RESUMO

The extent, range, and nature of available research in the field of primary Sjögren's syndrome (pSS) have not been understood fully. This study aimed to map the literature available on pSS, and identify global hotspots and trends in the research. Papers on pSS published between 2004 and 2021 were searched from Web of Science Core Collection. The quantity and citations of publications, and the research hotspots and trends in the field of pSS were analyzed and presented visually by Microsoft Excel and Citespace software. A total of 3606 papers mainly from 526 institutions in 83 countries/regions were included for analysis. The number of publications presented an overall upward trend in the field of pSS from 2004 to 2021. The USA ranked first in the number of publications (n = 661), followed by China (n = 491), Italy (n = 405), France (n = 351), and Japan (n = 292). Moreover, seven of the top ten countries by the number of publications on pSS were from Europe. The University of Groningen (n = 661), Xavier Mariette (n = 95), and Clinical and Experimental Rheumatology (n = 184) were the most prolific affiliation, author, and journal, respectively. Vitali C (n = 2009) and Arthritis and Rheumatism (n = 3918) held the record for the most cited papers by an author and journal, respectively. At present, the hot keywords in the field of pSS include disease activity, ultrasonography, management, consensus, and data-driven. Lymphoid organization, clinical phenotypes outcome, salivary gland ultrasonography, and Toll-like receptor are the emerging research trends in pSS. Research on pSS is flourishing. Current research of pSS mainly focuses on disease activity, ultrasonography, and management. While, the emerging research trends in pSS are lymphoid organization, clinical phenotypes outcome, salivary gland ultrasonography, and Toll-like receptor.


Assuntos
Síndrome de Sjogren , Bibliometria , Estudos Transversais , Humanos , Publicações , Glândulas Salivares , Síndrome de Sjogren/diagnóstico
6.
Front Mol Neurosci ; 17: 1400668, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38817551

RESUMO

Objective: This study aims to visualize the trends and hotspots in the research of "ferroptosis in PD" and "pyroptosis in PD" through bibliometric analysis from the past to 2024. Methods: Literature was retrieved from the Web of Science Core Collection (WoSCC) from the past to February 16, 2024, and bibliometric analysis was conducted using Vosviewer and Citespace. Results: 283 and 542 papers were collected in the field of "ferroptosis in PD" and "pyroptosis in PD." The number of publications in both fields has increased yearly, especially in "ferroptosis in PD," which will become the focus of PD research. China, the United States and England had extensive exchanges and collaborations in both fields, and more than 60% of the top 10 institutions were from China. In the fields of "ferroptosis in PD" and "pyroptosis in PD," the University of Melbourne and Nanjing Medical University stood out in terms of publication numbers, citation frequency, and centrality, and the most influential journals were Cell and Nature, respectively. The keyword time zone map showed that molecular mechanisms and neurons were the research hotspots of "ferroptosis in PD" in 2023, while memory and receptor 2 were the research hotspots of "pyroptosis in PD" in 2023, which may predict the future research direction. Conclusion: This study provides insights into the development, collaborations, research themes, hotspots, and tendencies of "ferroptosis in PD" and "pyroptosis in PD." Overall situation of these fields is available for researchers to further explore the underlying mechanisms and potential treatments.

7.
Dalton Trans ; 52(4): 1052-1061, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36602082

RESUMO

The spectrum and size controllable synthesis of gold nanorods is of great value for their widely applicable aspect ratio dependence of anisotropic surface plasmon resonance. Herein, 1,7-dihydroxynaphthalene with a relatively strong reducibility is proposed as a reducing agent for the controllable synthesis of gold nanorods. The result indicated that gold nanorods with high monodispersity, high shape yield, relatively small diameters, and maximum plasmon resonance wavelength of above 1000 nm can be acquired. More importantly, by virtue of the reducing agent used, fine and precise controls over the plasmon wavelength and diameter of the rod can be achieved via changes in experimental conditions. In particular, increases in the concentration of both silver ions and cetyltrimethylammonium bromide (CTAB) can increase the plasmon wavelength from around 600 nm to 1000 nm but respectively show a decreased diameter with the smallest value of around 14.3 nm and a mildly increased diameter from around 9.0 nm to 14.3 nm; moreover, increasing the concentration of reducing agents and gold seeds can simultaneously cause decreases in the plasmon wavelength from around 1000 nm to 800 nm and the diameters from around 14.3 nm to 9.0 and 7.3 nm, respectively. This powerful and efficient method of controllable synthesis of AuNRs could be valuable and attractive for the application of the as-obtained particles.


Assuntos
Nanotubos , Substâncias Redutoras , Ouro , Cetrimônio , Compostos de Cetrimônio
8.
Front Immunol ; 14: 1063018, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36969240

RESUMO

Background: Autophagy in osteoarthritis (OA) has become an active area of research with substantial value and potential. Nevertheless, few bibliometric studies have systematically analyzed the available research in the field. The main goal of this study was to map the available literature on the role of autophagy in OA and identify global research hotspots and trends. Methods: The Web of Science Core Collection and Scopus databases were interrogated for studies of autophagy in OA published between 2004 and 2022. Microsoft Excel, VOSviewer and CiteSpace software were used to analyze and visualize the number of publications and associated citations, and reveal global research hotspots and trends in the autophagy in OA field. Results: 732 outputs published by 329 institutions from 55 countries/regions were included in this study. From 2004 to 2022, the number of publications increased. China produced the most publications (n=456), prior to the USA (n=115), South Korea (n=33), and Japan (n=27). Scripps Research Institute (n=26) was the most productive institution. Martin Lotz (n=30) was the highest output author, while Caramés B (n=302) was the highest output author. Osteoarthritis and Cartilage was the most prolific and most co-cited journal. Currently, the autophagy in OA research hotspots include chondrocyte, transforming growth factor beta 1 (TGF-ß1), inflammatory response, stress, and mitophagy. The emerging research trends in this field are AMPK, macrophage, senescence, apoptosis, tougu xiaotong capsule (TXC), green tea extract, rapamycin, and dexamethasone. Novel drugs targeting specific molecule such as TGF-ß and AMPK have shown therapeutic potential but are still in the preclinical stage of development. Conclusions: Research on the role of autophagy in OA is flourishing. Martin Lotz, Beatriz Caramés, and Osteoarthritis and Cartilage have made outstanding contributions to the field. Prior studies of OA autophagy mainly focused on mechanisms underlying OA and autophagy, including AMPK, macrophages, TGF-ß1, inflammatory response, stress, and mitophagy. Emerging research trends, however, are centered around the relationship between autophagy, apoptosis, and senescence, as well as drug candidates such as TXC and green tea extract. The development of new targeted drugs that enhance or restore autophagic activity is a promising strategy for the treatment of OA.


Assuntos
Produtos Biológicos , Fator de Crescimento Transformador beta1 , Proteínas Quinases Ativadas por AMP , Autofagia , Antioxidantes , Bibliometria , Chá
9.
Polymers (Basel) ; 14(23)2022 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-36501556

RESUMO

A series of polyurethane/graphene oxide (PU/GO) solid-solid phase change materials (SSPCMs) were synthesized by using GO as a light-absorbing filler and polyethylene glycol (PEG) as a phase change matrix. The effects of PEG content on the energy storage capacity, thermal stability and photo-thermal conversion performance of PU were investigated. The results show that the form-stability of PU/GO decreases while the phase change enthalpy and photo-thermal conversion efficiency of PU/GO increases with the increasing PEG content. The introduction of a very low content of GO can maintain comparable energy storage density and greatly improve light absorption by reasonably modulating the soft segment contents. The PU/GO composite with 92 wt% PEG has a phase change enthalpy of 138.12 J/g and a high photo-thermal conversion efficiency (87.6%). The composite solid-solid PCMs have great potential for effective energy storage and solar energy utilization.

10.
Environ Sci Pollut Res Int ; 29(9): 13534-13540, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34595700

RESUMO

Activated coke-based catalysts have attracted extensive attention in denitration by selective catalytic reduction by NH3 (NH3-SCR), due to their excellent catalytic performance at low temperature. In the paper, the V2O5/AC catalyst was prepared by the impregnation method to investigate the effect of pre-oxidation process on its NH3-SCR activity. Activity test results show that the V2O5/AC catalyst with 4-h pre-oxidation exhibits the best NOx removal efficiency, which reaches the NOx conversion is over 75% in the range of 200-240 °C and exhibits an excellent resistance to SO2 and H2O. Characterization results demonstrate that the V4+ was oxidized by oxygen molecule during pre-oxidation process, which contributes to the formation of V5+ ions and surface-active oxygen species. The surface-active oxygen species are conducive to promoting the "fast SCR" reaction; thus, the pre-oxidized process can contribute to the superior NH3-SCR performance for V2O5/AC catalyst at low temperature.


Assuntos
Amônia , Temperatura Baixa , Catálise , Oxirredução , Temperatura
11.
Nanomaterials (Basel) ; 12(8)2022 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-35457990

RESUMO

The thermal transport of Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanofiber is contributed by the electronic component of thermal conduction and the phonon component of thermal conduction. The relationship between the electrical conductivity and thermal conductivity of these conducting polymers is of great interest in thermoelectric energy conversation. In this work, we characterized the axial electrical conductivities and thermal conductivities of the single PEDOT:PSS nanofibers and found that the Lorenz number L is larger than Sommerfeld value L0 at 300 K. In addition, we found that the L increased significantly in the low-temperature region. We consider that this trend is due to the bipolar contribution of conducting polymers with low-level electrical conductivity and the increasing trend of the electronic contribution to thermal conductivity in low-temperature regions.

12.
ACS Appl Bio Mater ; 4(9): 6742-6757, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-35006976

RESUMO

The global rise of antibiotic resistance of pathogenic bacteria has become an increasing medical and public concern, which is further urging the development of antimicrobial channels for treating infectious diseases. The combination of photodynamic therapy (PDT) with photothermal therapy (PTT) has been considered as a promising alternative way for the replacement of traditional antibiotic therapy. In this research, the newly fabricated Chlorin-e6 (Ce6) conjugated mesoporous silica-coated AuNRs, designated AuNR@SiO2-NH2-Ce6, exhibited synergistic photothermal effects and single oxygen localized generation property, and showed stronger photoinactivation for bacteria compared with Ce6. AuNR@SiO2-NH2-Ce6 can anchor to the cell membrane and accumulate in the interior of cells. Furthermore, the unique porous structure of AuNR@SiO2NH2 enabled Ce6 encapsulation in the mesopores and was subsequently released and activated by photothermic effect, allowing the generated single oxygen to penetrate into the cytoplasmic membrane or directly enter the interior of bacteria cells, thus overcoming the inherent defects of single oxygen. AuNR@SiO2-NH2-Ce6 not only damaged the integrity of the cell membrane of bacteria but also facilitated the cellular permeation and accumulation of external nanoagents in the bacteria upon light irradiation. In addition, AuNR@SiO2-NH2-Ce6 exhibited negligible cytotoxicity toward mammalian cells and hemolytic activity. Therefore, AuNR@SiO2-NH2-Ce6 may be highly promising candidates as topical antibacterial agents, and this study has wide implications on the design of next-generation antimicrobial agents.


Assuntos
Clorofilídeos , Nanotubos , Animais , Bactérias , Ouro/farmacologia , Mamíferos , Nanotubos/química , Oxigênio , Fármacos Fotossensibilizantes/farmacologia , Dióxido de Silício/farmacologia
13.
Viruses ; 13(10)2021 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-34696461

RESUMO

The influenza A virus (IAV) is an important cause of respiratory disease worldwide. It is well known that alveolar epithelial cells are the target cells for the IAV, but there is relatively limited knowledge regarding the role of macrophages during IAV infection. Here, we aimed to analyze transcriptome differences in mouse lungs and macrophage (RAW264.7) cell lines infected with either A/California/04/2009 H1N1 (CA09) or A/chicken/SD/56/2015 H9N2 (SD56) using deep sequencing. The uniquely differentially expressed genes (UDEGs) were analyzed with the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases; the results showed that the lungs infected with the two different viruses had different enrichments of pathways and terms. Interestingly, CA09 virus infection in mice was mostly involved with genes related to the extracellular matrix (ECM), while the most significant differences after SD56 infection in mice were in immune-related genes. Gene set enrichment analysis (GSEA) of RAW264.7 cells revealed that regulation of the cell cycle was of great significance after CA09 infection, whereas the regulation of the immune response was most enriched after SD56 infection, which was consistent with analysis results in the lung. Similar results were obtained from weighted gene co-expression network analysis (WGCNA), where cell cycle regulation was extensively activated in RAW264.7 macrophages infected with the CA09 virus. Disorder of the cell cycle is likely to affect their normal immune regulation, which may be an important factor leading to their different prognoses. These results provide insight into the mechanism of the CA09 virus that caused a pandemic and explain the different reactivities of monocytes/macrophages infected by H9N2 and H1N1 IAV subtypes.


Assuntos
Vírus da Influenza A/genética , Pulmão/virologia , Infecções por Orthomyxoviridae/virologia , RNA-Seq/métodos , Células Epiteliais Alveolares/virologia , Animais , Linhagem Celular , Modelos Animais de Doenças , Cães , Células Epiteliais/virologia , Perfilação da Expressão Gênica , Ontologia Genética , Imunidade , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H9N2/genética , Macrófagos , Células Madin Darby de Rim Canino , Camundongos , Infecções por Orthomyxoviridae/imunologia , Prognóstico , Células RAW 264.7 , Transcriptoma , Virulência
14.
Chin J Integr Med ; 26(7): 490-496, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32048170

RESUMO

OBJECTIVE: To evaluate the efficacy and safety of a Chinese medicine (CM) Modified Qufeng Runmian Powder (, MQFRMP) for the treatment of acne vulgaris with CM syndromes of dampness and blood stasis. METHODS: In this multicenter, randomized, double-blind, placebo-controlled clinical trial, 220 acne vulgaris patients with CM syndrome of dampness and blood stasis were included and randomly assigned using a central area group random design to receive either MQFRMP or the placebo, with 110 cases in each group. MQFRMP or a placebo at 145 g/bag were administered once daily for 4 weeks, respectively. The primary index of efficacy was the effective rate according to the acne severity score (ASS). The secondary indices of efficacy included the changes in the dermatology life quality index (DLQI) score, VISIA scores (spots, pores, brown spots, porphyrins and red areas) and skin assessment (skin pH, sebum amount and hydration) according to a SOFT skin multianalyzer. RESULTS: (1) Follow-up: a total of 204 patients completed the follow-up, with 103 in the treatment group and 101 in the control group. (2) Effective rate: the total effective rate of the treatment group was significantly higher than the control group [83.5% (86/103) vs. 31.7% (32/101), P<0.01)] with 95% confidence interval of 39.3%-66.4%. (3) DLQI: DLQI scores were significantly decreased the treatment and control groups (both P<0.01), but the treatment group was more obvious than the placebo group (P<0.01). (4) VISIA scores: the scores of spots, brown spots and red areas in the treatment group decreased compared with baseline (P<0.05). In the control group, the scores of brown spots and pores decreased compared with baseline (P<0.05). The improvement was more obvious in the treatment group than in the control group for all items (P<0.05). (5) Skin assessment: the pH and sebum score in the both groups decreased drastically compared with the baseline (all P<0.01), however, the improvement was more obvious in the treatment group than in the control group (P<0.01). The hydration amount in the two groups showed no statistically significant difference compared with the baseline (both P>0.05). (6) Safety: two cases of mild drug allergy were observed in the treatment group. CONCLUSION: MQFRMP was effective and safe for the treatment of acne vulgaris with syndromes of dampness and blood stasis. (No. ChiCTR1900020479).


Assuntos
Acne Vulgar/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Adolescente , Adulto , Método Duplo-Cego , Feminino , Humanos , Masculino , Pós , Síndrome , Adulto Jovem
15.
Nanoscale ; 11(47): 22890-22898, 2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31763638

RESUMO

Facile synthesis of high quality gold nanorods (AuNRs) with a tunable size is of great value for applications of AuNRs in various fields and for the study of the growth mechanism of such anisotropic nanostructures. However, limitations usually exist in a specific synthetic protocol. In this work, using 3-aminophenol as the reducing agent, we present a AuNR synthetic strategy with an excellent comprehensive performance, which includes an exceptional monodispersity, a AuNR shape purity of around 99%, a conversion ratio of the gold precursor of about 91%, and an easily tuned longitudinal surface plasmon resonance wavelength ranging from 580 to ∼1050 nm. Studies on the impacts of the experimental parameters including silver ions, gold seeds, reducing agent, and cetyltrimethylammonium bromide (CTAB) revealed a profound recognition of the significant effect of the reductive atmosphere, in synergy with other parameters, in directing the growth and structural evolution of the gold seeds, thus deeply affecting the size, shape yield, monodispersity, and morphology of the final structure. These results could be immensely useful for the application and revelation of the growth mechanism of AuNRs.

16.
Adv Sci (Weinh) ; 4(12): 1700341, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29270343

RESUMO

In order to locate the optimal carrier concentrations for peaking the thermoelectric performance in p-type group IV monotellurides, existing efforts focus on aliovalent doping, either to increase (in PbTe) or to decrease (in SnTe and GeTe) the hole concentration. The limited solubility of aliovalent dopants usually introduces insufficient phonon scattering for thermoelectric performance maximization. With a decrease in the size of cation, the concentration of holes, induced by cation vacancies in intrinsic compounds, increases rapidly from ≈1018 cm-3 in PbTe to ≈1020 cm-3 in SnTe and then to ≈1021 cm-3 in GeTe. This motivates a strategy here for reducing the carrier concentration in GeTe, by increasing the mean size of cations and vice-versa decreasing the average size of anions through isovalent substitutions for increased formation energy of cation vacancy. A combination of the simultaneously resulting strong phonon scattering due to the high solubility of isovalent impurities, an ultrahigh thermoelectric figure of merit, zT of 2.2 is achieved in GeTe-PbSe alloys. This corresponds to a 300% enhancement in average zT as compared to pristine GeTe. This work not only demonstrates GeTe as a promising thermoelectric material but also paves the way for enhancing the thermoelectric performance in similar materials.

17.
ACS Appl Mater Interfaces ; 9(44): 38537-38544, 2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29047272

RESUMO

A novel photoelectrode of three-dimensional (3D) lupinus-like TiO2 nanorod@Sn3O4 nanosheet hierarchical heterostructured arrays (TiO2@Sn3O4 HHAs) on a transparent F-doped SnO2 glass substrate was designed and fabricated by a two-step solvothermal growth process. Photoelectrochemical (PEC) measurements showed that the 3D lupinus-like TiO2@Sn3O4 HHAs photoelectrode displayed enhanced photocurrent density (3-fold increase with respect to that of pure TiO2), improved conversion efficiency, more negative onset potential (from -0.13 to -0.33 V vs normal hydrogen electrode), and higher light on/off cycle stability. The improved PEC properties may be ascribable to the enhancement of light harvesting and large contact area with the electrolyte by increased surface area as well as improvement of charge transfer and collection through the synergistic effects between band structures and morphology.

18.
J Nanosci Nanotechnol ; 15(4): 3147-50, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26353552

RESUMO

Zinc oxide (ZnO) has attracted increasing attention as one of the most promising n-type thermo-electric materials, but its practice use was limited by high thermal conductivity and low electrical conductivity. Therefore, we herein prepared Co-doped ZnO nanoparticles by sol-gel method and then compressed nanoparticles into bulk materials through spark plasma sintering. The thermo-electric properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and ZT value, have been investigated. We found that the substitution of Co2+ causes the decrease of bandgap and the increase of carrier concentration, thus the improvement of electrical conductivity. At the same time, the Co-induced lattice distortion and nanoparticles reduce the thermal conductivity by shortening the mean free path (MFP) of the phonons. The resultant ZT is 0.037 for Zn0.9Co0.1O, which is more than 23-fold higher than that of the pure ZnO samples.

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