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1.
Langmuir ; 40(2): 1316-1326, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38156971

RESUMO

While legacy fluorosurfactants have already been categorized as persistent organic pollutants, there appeared to be many strategies to develop alternatives. In this work, fluoroether double-chain phosphate surfactants (C72 diPAP-Na and C72 diPAP-NH4) were designed and synthesized with the initial intention of exploring the creation of new fluorosurfactants containing oxygen heteroatoms in the fluorocarbon chain segments to provide an alternative to the legacy long-chain fluorosurfactants. Furthermore, it was expected that they would even exceed the existing 6:2 fluorotelomer surfactants (6:2 diPAP-Na and 6:2 diPAP-NH4). Compared with characterizations of surface activity, foam performance, and wettability, the results showed that each of them has its own distinctive performance. Although the C72 series as new fluoroether surfactants cannot fully replace the 6:2 series of fluorosurfactants in terms of performance, there is a possibility of substitution in some aspects, which is of positive significance for further exploration to improve alternatives to legacy fluorosurfactants.

2.
Inorg Chem ; 63(1): 909-914, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38123359

RESUMO

Developing efficient metal-organic framework (MOF) optical devices with tunable third-order nonlinear optical (NLO) properties is an important challenge for scientific research and practical application. Herein, 2D monometallic and hetero/homo-bimetallic porphyrin MOF thin films (ZnTCPP(M) M = H2, Fe, Zn) were fabricated using the liquid-phase epitaxial (LPE) layer-by-layer (LBL) method to investigate the metal substitution dependent third-order NLO behavior. The prepared homo-bimetallic ZnTCPP(Zn) thin film exhibited enhanced third-order NLO performance with a higher third-order nonlinear susceptibility of ∼4.21 × 10-7 esu compared to monometallic and hetero-bimetallic counterparts. Additionally, theoretical calculations were performed to complement the experimental findings and revealed that the enhanced NLO effect of the ZnTCPP(Zn) thin film is mainly attributed to the enhanced local excitation. These findings not only provide a comprehensive understanding of the relationship between metal types and the NLO behavior of porphyrin MOF thin films but also offer valuable insights into the design and optimization of NLO devices.

3.
J Immunol ; 208(12): 2675-2685, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35606050

RESUMO

The adaptive immune receptor repertoire consists of the entire set of an individual's BCRs and TCRs and is believed to contain a record of prior immune responses and the potential for future immunity. Analyses of TCR repertoires via deep learning (DL) methods have successfully diagnosed cancers and infectious diseases, including coronavirus disease 2019. However, few studies have used DL to analyze BCR repertoires. In this study, we collected IgG H chain Ab repertoires from 276 healthy control subjects and 326 patients with various infections. We then extracted a comprehensive feature set consisting of 10 subsets of repertoire-level features and 160 sequence-level features and tested whether these features can distinguish between infected individuals and healthy control subjects. Finally, we developed an ensemble DL model, namely, DL method for infection diagnosis (https://github.com/chenyuan0510/DeepID), and used this model to differentiate between the infected and healthy individuals. Four subsets of repertoire-level features and four sequence-level features were selected because of their excellent predictive performance. The DL method for infection diagnosis outperformed traditional machine learning methods in distinguishing between healthy and infected samples (area under the curve = 0.9883) and achieved a multiclassification accuracy of 0.9104. We also observed differences between the healthy and infected groups in V genes usage, clonal expansion, the complexity of reads within clone, the physical properties in the α region, and the local flexibility of the CDR3 amino acid sequence. Our results suggest that the Ab repertoire is a promising biomarker for the diagnosis of various infections.


Assuntos
COVID-19 , Aprendizado Profundo , Sequência de Aminoácidos , COVID-19/diagnóstico , Humanos , Receptores de Antígenos de Linfócitos T
4.
Clin Exp Immunol ; 214(1): 36-49, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-37422711

RESUMO

Esophageal squamous cell carcinoma (ESCC), one of the most commonly diagnosed and lethal malignant diseases, has a complex tumor ecosystem. An obvious requirement for T-cell-mediated tumor control is the infiltration of tumor-reactive T cells into the tumor. Here, we obtained detailed T-cell compositions in both ESCC tumors and matched peripheral blood mononuclear cells (PBMCs) at single-cell resolution. We demonstrated that T cells in tumors and PBMCs had different compositions and functional states. ESCC tumors were rich in Treg and exhausted T cells but poor in cytotoxic and naïve T cells compared with PBMCs. The exhausted T cells showed higher exhausted signature in tumors than in PBMCs, while the cytotoxic T cells exhibited higher cytotoxic signature in PBMCs than in tumors. Our data indicated an immunosuppressive status and a defect at the level of T-cell priming in the tumor microenvironment. Leukocyte-associated Ig-like receptor-2 (LAIR2), a soluble collagen receptor that prevents the binding of human leukocyte-associated Ig-like receptor-1 (LAIR1) to collagens, was predominantly expressed in proliferating CD8+ T and Treg cells in tumors but in cytotoxic cells in PBMCs. LAIR2 could inhibit tumor metastasis, invasion, and collagen deposition via suppressing transforming growth factor-ß signaling. These findings revealed differential T-cell populations in tumors and PBMCs and provided convincing evidence that LAIR2 acted as a tumor suppressor.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Carcinoma de Células Escamosas do Esôfago/patologia , Neoplasias Esofágicas/patologia , Leucócitos Mononucleares/patologia , Ecossistema , Linfócitos T Reguladores , Microambiente Tumoral
5.
Respir Res ; 24(1): 301, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38041059

RESUMO

BACKGROUND: It is now understood that ferroptosis plays a significant role in the progression of chronic obstructive pulmonary disease (COPD) induced by cigarette smoke extract (CSE). However, the mechanisms underlying this relationship remain largely unclear. METHODS: In this study, we established a COPD mouse model through exposure to cigarette smoke particulates, followed by H&E staining, analysis of bronchoalveolar lavage fluid, and immunohistochemistry assay. A549 cells were exposed to increasing concentrations of CSE, with the addition of the ferroptosis activator erastin or the inhibitor Fer-1. Cell viability, LDH (lactate dehydrogenase) release, inflammatory cytokines, total ROS (reactive oxygen species), and lipid ROS were measured using the corresponding assay kits. The acetylation level of GNPAT was determined through immunoprecipitation. We assessed the expression levels of molecules involved in plasmalogen biosynthesis (FAR1, AGPS, and GNPAT), GPX4, and SIRT4 using quantitative real-time PCR, western blot analysis, and immunofluorescence staining. RESULTS: CSE-induced lung tissue damage was initially observed, accompanied by oxidative stress, ferroptosis, and increased plasmalogen biosynthesis molecules (FAR1, AGPS, and GNPAT). CSE also induced ferroptosis in A549 cells, resulting in reduced cell viability, GSH, and GPX4 levels, along with increased LDH, ROS, MDA (malondialdehyde) levels, oxidized lipids, and elevated FAR1, AGPS, and GNPAT expression. Knockdown of GNPAT mitigated CSE-induced ferroptosis. Furthermore, we found that CSE regulated the acetylation and protein levels of GNPAT by modulating SIRT4 expression. Importantly, the overexpression of GNPAT countered the inhibitory effects of SIRT4 on ferroptosis. CONCLUSIONS: Our study revealed GNPAT could be deacetylated by SIRT4, providing novel insights into the mechanisms underlying the relationship between CSE-induced ferroptosis and COPD.


Assuntos
Ferroptose , Doença Pulmonar Obstrutiva Crônica , Camundongos , Animais , Espécies Reativas de Oxigênio/metabolismo , Plasmalogênios/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Pulmão/metabolismo , Nicotiana
6.
Langmuir ; 39(41): 14519-14527, 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37802506

RESUMO

Fluorinated surfactants are widely used in many fields because of their excellent surface active properties, but their high stability has caused many environmental problems. With the ban and restriction of classical long-chain fluorinated surfactants such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) worldwide, the development and replacement of their alternatives is now a major challenge. How to reduce environmental persistence, bioaccumulation, and biotoxicity while maintaining high surface activity has become an important issue in the development of fluorinated surfactants. Using short-chain fluorinated surfactants is one of the important solutions to resolve the pollution of organic fluorinated compounds. In this article, we synthesized two short-chain fluorinated surfactants with ether bonds. One of them 6:2 FTESNa (2) used the perfluoroalkyl chain (n-C6F13-) and the other C72 FEESNa (4) used the fluoroether segment with six fluorinated carbons and two oxygens (CF3OCF(CF3)CF2OCF(CF3)). The surface activity, foam performance, and wettability of the two molecules were measured. The surface tensions at critical micelle concentration (γcmc) and the critical micelle concentration (cmc) of 2 and 4 were 17.6 mN/m (2.2 g/L) and 20.2 mN/m (4.6 g/L), respectively. Both of them were significantly superior to the surface activity of 6:2 FTSNa (7) which is one of the current alternatives for PFOS. Additionally, the foamability and foam stability of both 2 and 4 were better than that of 7. In the aspect of wettability on PTFE, that of 4 was greater than those of 2 and 7. In summary, this work provided a new choice for alternatives of PFOS and PFOA.

7.
J Org Chem ; 88(11): 7518-7524, 2023 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-37134234

RESUMO

A direct electrophilic difluoroalkylthiolation reaction of indole derivatives and other electron-rich heterocycles using methyl 2,2-difluoro-2-(chlorsulfonyl)acetate (ClSO2CF2COOMe) derived from Chen's reagent (FSO2CF2COOMe) is described. The ester group in the product can be further utilized in subsequent versatile transformations. The reactions provide good yields of the corresponding difluoroalkylthiolation products and exhibit high functional group compatibility. It is expected to serve as an alternative and practical protocol for difluoroalkylthiolation of various heterocycles.

8.
J Am Chem Soc ; 143(25): 9595-9600, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34128669

RESUMO

Ligands in ligand-protected metal clusters play a crucial role, not only because of their interaction with the metal core, but also because of the functionality they provide to the cluster. Here, we report the utilization of secondary phosphine oxide (SPO), as a new family of functional ligands, for the preparation of an undecagold cluster Au11-SPO. Different from the commonly used phosphine ligand (i.e., triphenylphosphine, TPP), the SPOs in Au11-SPO work as electron-withdrawing anionic ligands. While coordinating to gold via the phosphorus atom, the SPO ligand keeps its O atom available to act as a nucleophile. Upon photoexcitation, the clusters are found to inject holes into p-type semiconductors (here, bismuth oxide is used as a model), sensitizing the p-type semiconductor in a different way compared to the photosensitization of a n-type semiconductor. Furthermore, the Au11-SPO/Bi2O3 photocathode exhibits a much higher activity toward the hydrogenation of benzaldehyde than a TPP-protected Au11-sensitized Bi2O3 photocathode. Control experiments and density functional theory studies point to the crucial role of the cooperation between gold and the SPO ligands on the selectivity toward the hydrogenation of the C═O group in benzaldehyde.

9.
Org Biomol Chem ; 19(41): 8999-9003, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34605502

RESUMO

This paper reports a convenient copper-catalyzed three-component conversion of arylhydrazine hydrochlorides to arenesulfonyl fluorides in good yields under mild conditions, using 1,4-diazabicyclo [2.2.2]octane bis(sulfur dioxide) (DABSO) as a sulfonyl source and N-fluorobenzenesulfonimide (NFSI) as a fluorine source based on a radical sulfur dioxide insertion and fluorination strategy. Notably, arylhydrazine hydrochloride is used as a safe precursor of aryl radicals.

10.
Neoplasma ; 68(4): 683-691, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33618518

RESUMO

Hepatocellular carcinoma (HCC) is one of the most aggressive types of cancer and currently lacks effective treatment strategies. The present study revealed that deoxyribonuclease 1 like 3 (DNase1L3) expression levels were significantly downregulated in numerous types of gastrointestinal cancer, and especially in HCC. Tissue microarrays were further used to illustrate that DNase1L3 expression levels were frequently downregulated in HCC tissues compared with normal liver tissues. In addition, DNase1L3 expression levels were identified to be significantly associated with tumor size (p=0.0028), tumor thrombus formation (p<0.01), and a poorer overall survival (p=0.005) and disease-free survival (p=0.006) of HCC. Gene Ontology functional term enrichment analysis of biological processes discovered that DNase1L3 was significantly associated with complement activation. Further studies demonstrated that the ectopic expression of DNase1L3 suppressed cell growth and inhibited the PI3K/AKT signaling pathway activation following C3a receptor agonist treatment. In conclusion, the findings of the present study suggested, for the first time, that DNase1L3 may serve as a biomarker for the prognosis of patients with HCC, and may suppress HCC growth via inhibiting the PI3K/AKT signaling pathway.


Assuntos
Carcinoma Hepatocelular , Proteínas do Sistema Complemento/fisiologia , Endodesoxirribonucleases , Neoplasias Hepáticas , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Proliferação de Células , Endodesoxirribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo
11.
Br J Nutr ; 123(4): 428-436, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-31760957

RESUMO

The aim of the present study was to explore the influence of tea consumption on diabetes mellitus in the Chinese population. This multi-centre, cross-sectional study was conducted in eight sites from south, east, north, west and middle regions in China by enrolling 12 017 subjects aged 20-70 years. Socio-demographic and general information was collected by a standardised questionnaire. A standard procedure was used to measure anthropometric characteristics and to obtain blood samples. The diagnosis of diabetes was determined using a standard 75-g oral glucose tolerance test. In the final analysis, 10 825 participants were included and multiple logistic models and interaction effect analysis were applied for assessing the association between tea drinking with diabetes. Compared with non-tea drinkers, the multivariable-adjusted OR for newly diagnosed diabetes were 0·80 (95 % CI 0·67, 0·97), 0·88 (95 % CI 0·71, 1·09) and 0·86 (95 % CI 0·67, 1·11) for daily tea drinkers, occasional tea drinkers and seldom tea drinkers, respectively. Furthermore, drinking tea daily was related to decreased risk of diabetes in females by 32 %, elderly (>45 years) by 24 % and obese (BMI > 30 kg/m2) by 34 %. Moreover, drinking dark tea was associated with reduced risk of diabetes by 45 % (OR 0·55; 95 % CI 0·42, 0·72; P < 0·01). The results imply that drinking tea daily was negatively related to risk of diabetes in female, elderly and obese people. In addition, drinking dark tea was associated with decreased risk of type 2 diabetes mellitus.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Dieta/métodos , Comportamento de Ingestão de Líquido/fisiologia , Chá , Adulto , Idoso , China/epidemiologia , Estudos Transversais , Diabetes Mellitus Tipo 2/etiologia , Feminino , Teste de Tolerância a Glucose , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Adulto Jovem
12.
Bioprocess Biosyst Eng ; 43(3): 429-437, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31679050

RESUMO

This study introduces an effective method to deposit polypyrrole (PPy) on graphite felt (GF) as anode to improve the start-up performance of microbial fuel cells (MFCs). The results of scanning electron microscope (SEM) and electrochemical testing reveal that polypyrrole is able to improve the electrical conductivity and surface roughness, which is beneficial to the microorganism attachment and growth. It shows that microorganisms grow faster on polypyrrole-modified anode than on unmodified anode. It takes ca. 5 days for polypyrrole-modified anode to reach a reproducible voltage platform, while it takes 11 days for unmodified anode. Moreover, the maximum power density of microbial fuel cells with polypyrrole-modified anode was 919 mW m-2, which were 2.3 times of that with unmodified anode. This research revealed that polypyrrole modification can improve the start-up performance of microbial fuel cells. It is considered as a feasible, economical and sustainable anode.


Assuntos
Fontes de Energia Bioelétrica , Condutividade Elétrica , Grafite/química , Polímeros/química , Pirróis/química , Eletrodos
13.
Angew Chem Int Ed Engl ; 59(20): 7748-7754, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32068941

RESUMO

The deposition of an atomically precise nanocluster, for example, Ag44 (SR)30 , onto a large-band-gap semiconductor such as TiO2 allows a clear interface to be obtained to study charge transfer at the interface. Changing the light source from visible light to simulated sunlight led to a three orders of magnitude enhancement in the photocatalytic H2 generation, with the H2 production rate reaching 7.4 mmol h-1 gcatalyst -1 . This is five times higher than that of TiO2 modified with Ag nanoparticles and even comparable to that of TiO2 modified with Pt nanoparticles under similar conditions. Energy band alignment and transient absorption spectroscopy reveal that the role of the metal clusters is different from that of both organometallic complexes and plasmonic nanoparticles: A type II heterojunction charge-transfer route is achieved under UV/Vis irradiation, with the cluster serving as a small-band-gap semiconductor. This results in the clusters acting as co-catalysts rather than merely photosensitizers.

14.
Diabetes Metab Res Rev ; 35(5): e3143, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30768758

RESUMO

AIM: The purpose of this study is to explore the long-term effects of aerobic training (AT), resistance training (RT), and combined training (AT + RT) on the prevention of T2D incidence in patients with prediabetes. MATERIALS AND METHODS: In this randomised controlled trial, people with prediabetes (fasting glucose ≥5.6 and <7.0 mmol/L and/or 2-h glucose ≥7.8 and <11.1 mmol/L on the 75-g oral glucose tolerance test and/or haemoglobin A1c ≥5.7% and <6.4%) were randomly assigned to the control group, AT group, RT group, or AT + RT group. Supervised exercise programmes, including AT, RT, and AT + RT, were completed for 60 minutes per day, three non-consecutive days per week for 24 months. The primary outcome was the incidence of T2D; secondary outcomes were blood glucose and lipid levels, including total cholesterol (TC) and standard 2-hour oral glucose tolerance (2hPG). RESULTS: A total of 137 (80%) subjects with a mean age of 59 years (45 men, 92 women) entered the final analysis. After 24 months of intervention, the incidences of T2D adjusted by sex and age were significantly decreased by 74% (95% CI, 38-89), 65% (95% CI, 21-85), and 72% (95% CI, 36-87) in the AT + RT, RT, and AT groups compared with the control group (HR: AT + RT 0.26 [95% CI, 0.11-0.62], RT 0.35 [95% CI, 0.15-0.79], and AT 0.28 [95% CI, 0.13-0.64]). The cumulative T2D incidences were significantly lower in the AT + RT, RT, and AT groups than in the control group (21%, 26%, and 22% vs 69%). The blood glucose and lipid profiles improved more in the AT, RT, and AT + RT groups than in the control group. CONCLUSION: RT and RT plus AT were as effective as isolated AT in preventing progression to T2D.


Assuntos
Diabetes Mellitus Tipo 2/prevenção & controle , Terapia por Exercício/métodos , Estado Pré-Diabético/terapia , Treinamento Resistido/métodos , Idoso , Glicemia/análise , China/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Jejum , Feminino , Teste de Tolerância a Glucose , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Condicionamento Físico Humano/métodos , Estado Pré-Diabético/sangue , Estado Pré-Diabético/epidemiologia , Resultado do Tratamento
15.
Chemistry ; 25(7): 1824-1828, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30444035

RESUMO

A versatile and general zinc-mediated intermolecular reductive radical fluoroalkylsulfination of unsaturated C-C bonds has been developed using readily available fluoroalkyl bromides and 1,4-diazabicyclo[2.2.2]octane-bis(sulfur dioxide) adduct (DABSO) with wide substrate scope and excellent functional group tolerance. Sulfur dioxide anion radical generated in situ from the reduction of sulfur dioxide with zinc may be involved in the reaction mechanism.

16.
Chemistry ; 25(18): 4814-4820, 2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30609232

RESUMO

The atomically precise bimetallic nanocluster (NC), Au24 Ag20 (PhCC)20 (SPy)4 Cl2 (1) (Py=pyridine), was employed for the first time as a stable photosensitizer for photoelectrochemical applications. The sensitization of TiO2 nanotube arrays (TNA) with 1 greatly enhances the light-harvesting ability of the composite because 1 shows a high molar extinction coefficient (ϵ) in the UV/Vis region. Compared to a more standard Au25 (SG)18 -TNA (2-TNA; SG=glutathione) composite, 1-TNA shows a much better stability under illumination in both neutral and basic conditions. The precise composition of the photosensitizers enables a direct comparison of the sensitization ability between 1 and 2. With the same cluster loading, the photocurrent produced by 1-TNA is 15 times larger than that of 2-TNA. The superior performance of 1-TNA over 2-TNA is attributed not only to the higher light absorption ability of 1 but also to the higher charge-separation efficiency. Besides, a ligand effect on the stability of the photoelectrode and charge-transfer between the NCs and the semiconductor is revealed. This work paves the way to study the role of metal nanoclusters as photosensitizers at the atomic level, which is essential for the design of better material for light energy conversion.

17.
Am J Respir Cell Mol Biol ; 58(6): 684-695, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29220578

RESUMO

Pulmonary fibrosis is a chronic progressive lung disease with few treatments. Human mesenchymal stem cells (MSCs) have been shown to be beneficial in pulmonary fibrosis because they have immunomodulatory capacity. However, there is no reliable model to test the therapeutic effect of human MSCs in vivo. To mimic pulmonary fibrosis in humans, we established a novel bleomycin-induced pulmonary fibrosis model in humanized mice. With this model, the benefit of human MSCs in pulmonary fibrosis and the underlying mechanisms were investigated. In addition, the relevant parameters in patients with pulmonary fibrosis were examined. We demonstrate that human CD8+ T cells were critical for the induction of pulmonary fibrosis in humanized mice. Human MSCs could alleviate pulmonary fibrosis and improve lung function by suppressing bleomycin-induced human T-cell infiltration and proinflammatory cytokine production in the lungs of humanized mice. Importantly, alleviation of pulmonary fibrosis by human MSCs was mediated by the PD-1/programmed death-ligand 1 pathway. Moreover, abnormal PD-1 expression was found in circulating T cells and lung tissues of patients with pulmonary fibrosis. Our study supports the potential benefit of targeting the PD-1/programmed death-ligand 1 pathway in the treatment of pulmonary fibrosis.


Assuntos
Antígeno B7-H1/metabolismo , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/fisiologia , Receptor de Morte Celular Programada 1/metabolismo , Fibrose Pulmonar/terapia , Animais , Bleomicina/toxicidade , Linfócitos T CD4-Positivos/patologia , Modelos Animais de Doenças , Humanos , Leucócitos Mononucleares/transplante , Redes e Vias Metabólicas , Camundongos Mutantes , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia
18.
Opt Express ; 26(7): 9017-9026, 2018 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-29715860

RESUMO

Previously, PbS/CdS core/shell quantum dots with excellent optical properties have been widely used as light-harvesting materials in solar cell and biomarkers in bio-medicine. However, the nonlinear absorption characteristics of PbS/CdS core/shell quantum dots have been rarely investigated. In this work, PbS/CdS core/shell quantum dots were successfully employed as nonlinear saturable absorber (SA) for demonstrating a mode-locked Er-doped fiber laser. Based on a film-type SA, which was prepared by incorporating the quantum dots with the polyvinyl alcohol (PVA), mode-locked Er-doped operation with a pulse width of 54 ps and a maximum average output power of 2.71 mW at the repetition rate of 3.302 MHz was obtained. Our long-time stable results indicate that the CdS shell can effectively protect the PbS core from the effect of photo-oxidation and PbS/CdS core/shell quantum dots were efficient SA candidates for demonstrating pulse fiber lasers due to its tunable absorption peak and excellent saturable absorption properties.

19.
J Org Chem ; 83(23): 14588-14599, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30403488

RESUMO

The reaction of trifluoromethylated tertiary bromides with isonitriles induced by visible light is reported. Defluorination was avoided in a radical process. This method provides an efficient approach to compounds containing a trifluoromethylated quaternary carbon center, most of which show excellent potential to be agrochemicals. In addition, the bromides were prepared from perfluoroisobutylene, which is a waste from industry, after several steps. This reaction shows a feasible transfer of harmful waste into useful compounds.

20.
J Org Chem ; 83(10): 5836-5843, 2018 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-29658711

RESUMO

An efficient oxidative radical intermolecular trifluoromethylthioarylation of styrenes with arenediazonium salts and copper(I) trifluoromethylthiolate under mild conditions is described for the first time. The reactions provide good yields of the corresponding trifluoromethylthioarylation products with broad substrate scope and excellent functional group compatibility.

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