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1.
Cell Rep ; 43(3): 113872, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38427562

RESUMO

Infection, autoimmunity, and cancer are principal human health challenges of the 21st century. Often regarded as distinct ends of the immunological spectrum, recent studies hint at potential overlap between these diseases. For example, inflammation can be pathogenic in infection and autoimmunity. T resident memory (TRM) cells can be beneficial in infection and cancer. However, these findings are limited by size and scope; exact immunological factors shared across diseases remain elusive. Here, we integrate large-scale deeply clinically and biologically phenotyped human cohorts of 526 patients with infection, 162 with lupus, and 11,180 with cancer. We identify an NKG2A+ immune bias as associative with protection against disease severity, mortality, and autoimmune/post-acute chronic disease. We reveal that NKG2A+ CD8+ T cells correlate with reduced inflammation and increased humoral immunity and that they resemble TRM cells. Our results suggest NKG2A+ biases as a cross-disease factor of protection, supporting suggestions of immunological overlap between infection, autoimmunity, and cancer.


Assuntos
Doenças Autoimunes , Doenças Transmissíveis , Neoplasias , Humanos , Linfócitos T CD8-Positivos , Neoplasias/patologia , Autoimunidade , Inflamação/patologia , Doenças Autoimunes/patologia , Doenças Transmissíveis/patologia , Memória Imunológica
2.
Infect Agent Cancer ; 19(1): 4, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38378712

RESUMO

OBJECTIVES: Our aim was to assess the trend in gynaecologic cancer (GC) mortality in the period from 2010 to 2022 in the United States, with focus on the impact of the pandemic on increased deaths. METHODS: GC mortality data were extracted from the Center for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) platform. We analysed mortality trends and evaluated observed vs. predicted mortality for the period from 2020 to 2022 with joinpoint regression and prediction modelling analyses. RESULTS: A total of 334,382 deaths among adults aged 25 years and older with gynaecologic cancer were documented from 2010 to 2022. The overall age-standardised mortality rate (ASMR, per 100,000 persons) for ovarian cancer-related death decreased gradually from 7.189 in 2010 to 5.517 in 2019, yielding an APC (annual percentage change) of -2.8%. However, the decrease in ovarian cancer-related mortality slowed down by more than 4-fold during the pandemic. Cervical cancer -related mortality decreased slightly prior to the pandemic and increased during the pandemic with an APC of 0.6%, resulting in excess mortality of 4.92%, 9.73% and 2.03% in 2020, 2021 and 2022, respectively. For uterine corpus cancer, the ASMR increased from 1.905 in 2010 to 2.787 in 2019, and increased sharply to 3.079 in 2021 and 3.211 in 2022. The ASMR rose steadily between 2013 and 2022, yielding an APC of 6.9%. CONCLUSIONS: Overall, we found that GC-related mortality increased during the COVID-19 pandemic, and this increase was not specific to age, race, or ethnicity.

3.
Molecules ; 29(3)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38338347

RESUMO

The flower buds of three Panax species (PGF: P. ginseng; PQF: P. quinquefolius; PNF: P. notoginseng) widely consumed as health tea are easily confused in market circulation. We aimed to develop a green, fast, and easy analysis strategy to distinguish PGF, PQF, and PNF. In this work, fast gas chromatography electronic nose (fast GC e-nose), headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), and headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) were utilized to comprehensively analyze the volatile organic components (VOCs) of three flowers. Meanwhile, a principal component analysis (PCA) and heatmap were applied to distinguish the VOCs identified in PGF, PQF, and PNF. A random forest (RF) analysis was used to screen key factors affecting the discrimination. As a result, 39, 68, and 78 VOCs were identified in three flowers using fast GC e-nose, HS-GC-IMS, and HS-SPME-GC-MS. Nine VOCs were selected as potential chemical markers based on a model of RF for distinguishing these three species. Conclusively, a complete VOC analysis strategy was created to provide a methodological reference for the rapid, simple, and environmentally friendly detection and identification of food products (tea, oil, honey, etc.) and herbs with flavor characteristics and to provide a basis for further specification of their quality and base sources.


Assuntos
Panax , Compostos Orgânicos Voláteis , Cromatografia Gasosa-Espectrometria de Massas/métodos , Nariz Eletrônico , Microextração em Fase Sólida/métodos , Panax/química , Espectrometria de Mobilidade Iônica , Compostos Orgânicos Voláteis/análise , Flores/química , Chá
4.
Naunyn Schmiedebergs Arch Pharmacol ; 397(4): 2437-2445, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-37847411

RESUMO

Hepatocellular carcinoma (HCC) has high morbidity and mortality, and effective therapies are lacking. Gallic acid (GA), a natural phenolic compound derived from plants, has been reported to prevent the onset and progression of various cancers. However, there is limited elaboration on the potential mechanisms and anticancer effects of GA on hepatocellular carcinoma. Inducing ferroptosis of tumor cells has become one of the most promising ways to eradicate tumor cells. However, the effect of GA on HCC ferroptosis remains unknown. We evaluated the impact of GA on cell viability, migration, and mitochondrial morphology in HepG2 cells. Our study identified a critical role of GA in inducing ferroptosis in HepG2 cells. Mechanistically, we found that GA could inhibit the expression of a ferroptosis-related protein SLC7A11 and GPX4 in HepG2, by blocking ß-catenin transport from nuclear to the cytoplasm, thus inducing the inactivation of the Wnt/ß-catenin pathway. Our study has confirmed that GA is a novel ferroptosis inducer of HC, suggesting GA could be a promising candidate for the clinical treatment of HCC.


Assuntos
Carcinoma Hepatocelular , Ferroptose , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , beta Catenina/metabolismo , Via de Sinalização Wnt , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica
5.
Res Sq ; 2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37886475

RESUMO

Infection, autoimmunity, and cancer are the principal human health challenges of the 21st century and major contributors to human death and disease. Often regarded as distinct ends of the immunological spectrum, recent studies have hinted there may be more overlap between these diseases than appears. For example, pathogenic inflammation has been demonstrated as conserved between infection and autoimmune settings. T resident memory (TRM) cells have been highlighted as beneficial for infection and cancer. However, these findings are limited by patient number and disease scope; exact immunological factors shared across disease remain elusive. Here, we integrate large-scale deeply clinically and biologically phenotyped human cohorts of 526 patients with infection, 162 with lupus, and 11,180 with cancer. We identify an NKG2A+ immune bias as associative with protection against disease severity, mortality, and autoimmune and post-acute chronic disease. We reveal that NKG2A+ CD8+ T cells correlate with reduced inflammation, increased humoral immunity, and resemble TRM cells. Our results suggest that an NKG2A+ bias is a pan-disease immunological factor of protection and thus supports recent suggestions that there is immunological overlap between infection, autoimmunity, and cancer. Our findings underscore the promotion of an NKG2A+ biased response as a putative therapeutic strategy.

6.
Int J Biol Macromol ; 248: 125867, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37473892

RESUMO

BRAFV600E mutation is one of the most therapeutic targets in thyroid cancers. However, its specific inhibitors have shown little clinical benefit because they can reactivate the MAPK/ERK and PI3K/AKT pathways by feedback upregulating the transcription of HER3. Peptidyl-prolyl cis/trans isomerase Pin1 has been proven to be closely associated with tumor progression. Here, we aimed to determine antitumor activity of Pin1 inhibitor API-1 in thyroid cancer and its effect on cellular response to BRAF inhibitors. The results showed that API-1 exhibited strong antitumor activity against thyroid cancer. Meanwhile, it improved the response of BRAF-mutant thyroid cancer cells to BRAF inhibitor PLX4032 and there was a synergistic effect between them. Specially, a combination therapy of API-1 and PLX4032 significantly inhibited cell proliferation, colony formation, and the growth of xenograft tumors as well as induced cell apoptosis in BRAF-mutant thyroid cancer cells compared with API-1 or PLX4032 monotherapy. Similar results were also observed in transgenic mice with BrafV600E-driven thyroid cancer. Mechanistically, API-1 enhanced XPO5 ability to export pre-microRNA 20a (pre-miR-20a) from the nucleus to cytoplasm, thereby promoting the maturation of miR-20a-5p. Further studies showed that miR-20a-5p specifically targeted and down-regulated HER3, thereby blocking the reactivation of MAPK/ERK and PI3K/AKT signaling pathways caused by PLX4032. These results, taken together, demonstrate that Pin1 inhibitor API-1 significantly improves the sensitivity of BRAF-mutant thyroid cancer cells to PLX4032. Thus, this study not only determines the potential antitumor activity of Pin1 inhibitor API-1 in thyroid cancer but also offers an alternative therapeutic strategy for BRAF-mutant thyroid cancers by a combination of Pin1 inhibitor and BRAF kinase inhibitor.


Assuntos
MicroRNAs , Neoplasias da Glândula Tireoide , Humanos , Camundongos , Animais , Vemurafenib/farmacologia , Vemurafenib/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Sulfonamidas/farmacologia , Retroalimentação , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/metabolismo , Linhagem Celular Tumoral , Mutação , Carioferinas
7.
Cell Death Dis ; 14(7): 454, 2023 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-37479689

RESUMO

STAG2, an important subunit in cohesion complex, is involved in the segregation of chromosomes during the late mitosis and the formation of sister chromatids. Mutational inactivation of STAG2 is a major cause of the resistance of BRAF-mutant melanomas to BRAF/MEK inhibitors. In the present study, we found that STAG2 was frequently down-regulated in thyroid cancers compared with control subjects. By a series of in vitro and in vivo studies, we demonstrated that STAG2 knockdown virtually had no effect on malignant phenotypes of BRAF-mutant thyroid cancer cells such as cell proliferation, colony formation and tumorigenic ability in nude mice compared with the control. In addition, unlike melanoma, STAG2 knockdown also did not affect the sensitivity of these cells to MEK inhibitor. However, we surprisingly found that STAG2-knockdown cells exhibited more sensitive to glutamine deprivation or glutaminase inhibitor BPTES compared with control cells. Mechanistically, knocking down STAG2 in BRAF-mutant thyroid cancer cells decreases the protein stability of c-Myc via the ERK/AKT/GSK3ß feedback pathway, thereby impairing glutamine metabolism of thyroid cancer cells by down-regulating its downstream targets such as SCL1A5, GLS and GLS2. Our data, taken together, demonstrate that STAG2 inactivation reprograms glutamine metabolism of BRAF-mutant thyroid cancer cells, thereby improving their cellular response to glutaminase inhibitor. This study will provide a potential therapeutic strategy for BRAF-mutant thyroid cancers.


Assuntos
Proteínas Proto-Oncogênicas B-raf , Neoplasias da Glândula Tireoide , Animais , Humanos , Camundongos , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Glutaminase/metabolismo , Glutamina/genética , Melanoma/patologia , Camundongos Nus , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Mutação/genética , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias da Glândula Tireoide/genética
8.
Commun Biol ; 6(1): 528, 2023 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-37193826

RESUMO

The discovery and characterization of antigen-specific CD8+ T cell clonotypes typically involves the labor-intensive synthesis and construction of peptide-MHC tetramers. We adapt single-chain trimer (SCT) technologies into a high throughput platform for pMHC library generation, showing that hundreds can be rapidly prepared across multiple Class I HLA alleles. We use this platform to explore the impact of peptide and SCT template mutations on protein expression yield, thermal stability, and functionality. SCT libraries were an efficient tool for identifying T cells recognizing commonly reported viral epitopes. We then construct SCT libraries to capture SARS-CoV-2 specific CD8+ T cells from COVID-19 participants and healthy donors. The immunogenicity of these epitopes is validated by functional assays of T cells with cloned TCRs captured using SCT libraries. These technologies should enable the rapid analyses of peptide-based T cell responses across several contexts, including autoimmunity, cancer, or infectious disease.


Assuntos
Linfócitos T CD8-Positivos , COVID-19 , Humanos , SARS-CoV-2/genética , Antígenos , Epitopos , Peptídeos/genética
9.
Int J Mol Sci ; 24(4)2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36834830

RESUMO

BRAFV600E, the most common genetic alteration, has become a major therapeutic target in thyroid cancer. Vemurafenib (PLX4032), a specific inhibitor of BRAFV600E kinase, exhibits antitumor activity in patients with BRAFV600E-mutated thyroid cancer. However, the clinical benefit of PLX4032 is often limited by short-term response and acquired resistance via heterogeneous feedback mechanisms. Disulfiram (DSF), an alcohol-aversion drug, shows potent antitumor efficacy in a copper (Cu)-dependent way. However, its antitumor activity in thyroid cancer and its effect on cellular response to BRAF kinase inhibitors remain unclear. Antitumor effects of DSF/Cu on BRAFV600E-mutated thyroid cancer cells and its effect on the response of these cells to BRAF kinase inhibitor PLX4032 were systematically assessed by a series of in vitro and in vivo functional experiments. The molecular mechanism underlying the sensitizing effect of DSF/Cu on PLX4032 was explored by Western blot and flow cytometry assays. DSF/Cu exhibited stronger inhibitory effects on the proliferation and colony formation of BRAFV600E-mutated thyroid cancer cells than DSF treatment alone. Further studies revealed that DSF/Cu killed thyroid cancer cells by ROS-dependent suppression of MAPK/ERK and PI3K/AKT signaling pathways. Our data also showed that DSF/Cu strikingly increased the response of BRAFV600E-mutated thyroid cancer cells to PLX4032. Mechanistically, DSF/Cu sensitizes BRAF-mutant thyroid cancer cells to PLX4032 by inhibiting HER3 and AKT in an ROS-dependent way and subsequently relieving feedback activation of MAPK/ERK and PI3K/AKT pathways. This study not only implies potential clinical use of DSF/Cu in cancer therapy but also provides a new therapeutic strategy for BRAFV600E-mutated thyroid cancers.


Assuntos
Proteínas Proto-Oncogênicas B-raf , Neoplasias da Glândula Tireoide , Humanos , Vemurafenib/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Dissulfiram/uso terapêutico , Fosfatidilinositol 3-Quinases/metabolismo , Espécies Reativas de Oxigênio , Sulfonamidas/farmacologia , Indóis/farmacologia , Retroalimentação , Inibidores de Proteínas Quinases/farmacologia , Neoplasias da Glândula Tireoide/patologia , Linhagem Celular Tumoral
10.
Front Cardiovasc Med ; 9: 1036603, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36505392

RESUMO

Immune checkpoint inhibitors (ICIs) have significantly improved the survival of patients with advanced tumors. However, immune-related adverse events (irAEs) caused by ICIs, especially high-grade irAEs, are of growing concern. High-grade multisystem irAEs due to toripalimab, a programmed cell death-1 (PD-1) inhibitor, have been rarely reported. Two patients with malignant metastatic tumors were treated with anti-PD-1 immunotherapy. However, both patients developed high-grade multisystem irAEs based on myocarditis, with chest discomfort and malaise as the main clinical manifestation. Both patients had an elevation of cardiac enzymes, abnormal electrocardiography and left ventricular wall motion. Patient 2 was also diagnosed with organizing pneumonia. Immunotherapy was suspended. High-dose intravenous methylprednisolone was immediately initiated. The patients' symptoms were significantly relieved in a short period of time. Immunosuppressants were discontinued at the 6th month follow-up in patient 1 without relapse. However, patient 2 was lost to follow up due to financial reasons. To the best of our knowledge, this is the first report regarding ICI-associated myocarditis-pneumonia due to toripalimab, indicating the significance of early recognition and management of high-grade multisystem irAEs in clinical practice.

11.
Res Sq ; 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36415462

RESUMO

CD8 + cytotoxic T cell responses against viral infection represent a major element of the adaptive immune response. We describe the development of a peptide antigen - major histompatibility complex (pMHC) library representing the full SARS-CoV-2 viral proteome, and comprised of 634 pMHC multimers representing the A*02.01, A*24.02, and B*07.02 HLA alleles, as well as specific antigens associated with the cytomegalovirus (CMV). These libraries were used to capture non-expanded CD8 + T cells from blood samples collected from 64 infected individuals, and then analyzed using single cell RNA-seq. The discovery and characterization of antigen-specific CD8 + T cell clonotypes typically involves the labor-intensive synthesis and construction of peptide-MHC tetramers. We adapted single-chain trimer (SCT) technologies into a high throughput platform for pMHC library generation, showing that hundreds can be rapidly prepared across multiple Class I HLA alleles. We used this platform to explore the impact of peptide and SCT template mutations on protein expression yield, thermal stability, and functionality. SCT libraries were an efficient tool for identifying T cells recognizing commonly reported viral epitopes. We then constructed SCT libraries designed to capture SARS-CoV-2 specific CD8 + T cells from COVID-19 participants and healthy donors. The immunogenicity of these epitopes was validated by functional assays of T cells with cloned TCRs captured using SCT libraries. These technologies should enable the rapid analyses of peptide-based T cell responses across several contexts, including autoimmunity, cancer, or infectious disease.

12.
Curr Microbiol ; 79(5): 147, 2022 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-35397017

RESUMO

Enterococcus faecalis (E. faecalis) belongs to lactic acid bacteria which can be used as a probiotic additive and feed, bringing practical value to the health of humans and animals. The prebiotic function of tea polyphenols lays a foundation for green tea polyphenols (GTP) to repair the adverse changes of E. faecalis under stress conditions. In this study, RNA-sequence analysis was used to explore the protective effect of GTP on E. faecalis under bile salt stress. A total of 50 genes were found to respond to GTP under bile salts stress, containing 18 up-regulated and 32 down-regulated genes. The results showed that multiple genes associated with cell wall and membrane, transmembrane transport, nucleotide transport and metabolism were significantly differentially expressed (P < 0.05), while GTP intervention can partly alleviate the detrimental effects of bile salt on amino acid metabolism and transport. The present study provides the whole genome transcriptomics of E. faecalis under bile salt stress and GTP intervention which help us understand the growth and mechanism of continuous adaptation of E. faecalis under stress conditions.


Assuntos
Enterococcus faecalis , Polifenóis , Animais , Antioxidantes/farmacologia , Bile , Ácidos e Sais Biliares/metabolismo , Ácidos e Sais Biliares/farmacologia , Enterococcus faecalis/genética , Guanosina Trifosfato/metabolismo , Guanosina Trifosfato/farmacologia , Polifenóis/farmacologia , RNA-Seq , Estresse Salino , Chá/química , Transcriptoma
13.
Biomacromolecules ; 23(3): 960-971, 2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35029369

RESUMO

As a natural antitumor drug, curcumin (CUR) has received increasing attention from researchers and patients due to its various medicinal properties. However, currently CUR is still restricted due to its low and stand-alone therapeutic effects that seriously limit its clinical application. Here, by using cellulose nanocrystals (CNCs) as a nanocarrier to load CUR and AuNPs simultaneously, we developed a hybrid nanoparticle as a codrug delivery system to enhance the low and stand-alone therapeutic effects of CUR. Aided with the encapsulation of ß-cyclodextrin (ßCD), both the solubility and the stability of CUR are greatly enhanced (solubility increased from 0.89 to 131.7 µg/mL). Owing to the unique rod-like morphology of CNCs, the system exhibits an outstanding loading capacity of 31.4 µg/mg. Under the heat effects of coloaded AuNPs, the system demonstrates a high release rate of 77.63%. Finally, with CNC as a bridge nanocarrier, all aforementioned functions were integrated into one hybrid nanoparticle. The all-in-one integration ensures CUR to have enhanced therapeutic effects and enables the delivery system to exhibit combined chemo-photothermal therapy outcomes. This work presents a significant step toward CUR's clinical application and provides a new strategy for effective and integrative treatment of tumor disease.


Assuntos
Curcumina , Nanopartículas Metálicas , Nanopartículas , Curcumina/química , Portadores de Fármacos/química , Ouro/química , Humanos , Nanopartículas/química , Terapia Fototérmica
14.
Onco Targets Ther ; 13: 7933-7939, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32848419

RESUMO

EGFR-T790M and BRAFV600E are the common resistance mechanisms to EGFR-tyrosine kinase inhibitors (TKIs). Standard treatment for the triple mutations of EGFR-19del, T790M, and BRAFV600E is still under debate. Herein, we present a case of therapeutic efficacy of osimertinib and dabrafenib plus trametinib on a 63-year-old man with advanced lung adenocarcinoma. This patient reached a remarkable progression-free survival of 9 months without any serious adverse reaction. At the progression of the disease, C797S mutation in cis was detected by liquid biopsy. Subsequently, brigatinib with cetuximab was administered but no curative effect was observed. Then, therapy was changed to apatinib combined with osimertinib. The subsequent CT scan showed that the lesions reached stable disease (SD), and the survival benefit has been evaluated. This case showed that the combination treatment of osimertinib and dabrafenib plus trametinib might be a great treatment option for NSCLC patients with triple mutations (EGFR-19del/T790M/BRAFV600E).

15.
Sci China Life Sci ; 57(6): 575-80, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24829106

RESUMO

Signaling pathways transduce extracellular stimuli into cells through molecular cascades to regulate cellular functions. In stem cells, a small number of pathways, notably those of TGF-ß/BMP, Hedgehog, Notch, and Wnt, are responsible for the regulation of pluripotency and differentiation. During embryonic development, these pathways govern cell fate specifications as well as the formation of tissues and organs. In adulthood, their normal functions are important for tissue homeostasis and regeneration, whereas aberrations result in diseases, such as cancer and degenerative disorders. In complex biological systems, stem cell signaling pathways work in concert as a network and exhibit crosstalk, such as the negative crosstalk between Wnt and Notch. Over the past decade, genetic and genomic studies have identified a number of potential drug targets that are involved in stem cell signaling pathways. Indeed, discovery of new targets and drugs for these pathways has become one of the most active areas in both the research community and pharmaceutical industry. Remarkable progress has been made and several promising drug candidates have entered into clinical trials. This review focuses on recent advances in the discovery of novel drugs which target the Notch and Wnt pathways.


Assuntos
Transdução de Sinais/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos , Células-Tronco/fisiologia , Animais , Descoberta de Drogas , Humanos , Neoplasias/patologia , Neoplasias/fisiopatologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Células-Tronco Neoplásicas/fisiologia , Receptores Notch/antagonistas & inibidores , Receptores Notch/fisiologia , Células-Tronco/citologia , Via de Sinalização Wnt/efeitos dos fármacos
16.
Luminescence ; 23(3): 163-8, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18452133

RESUMO

Chemiluminescence (CL) was observed when benzene vapour passed through the surface of Y(2)O(3), TiO(2), Y(2)O(3)-V(2)O(5), TiO(2)-Y(2)O(3), Y(2)O(3)-Cr(2)O(3), Y(2)O(3)-Al(2)O(3) and TiO(2)-Al(2)O(3), with air as the carrier gas. The strongest CL intensity was found with Y(2)O(3) as the catalyst. A novel benzene sensor based on this kind of CL was developed. Quantitative analysis was performed at the wavelength of 425 nm. Under optimal conditions, CL intensity was directly proportional to the concentration of benzene vapour. The linear range was 4-7018 mg/m(3)(r = 0.9981, n = 11), with a detection limit of 1 mg/m(3) (the signal:noise ratio was 3). This gas sensor can work continuously for >80 h and has been successfully applied to the real-time determination of benzene vapour.


Assuntos
Benzeno/análise , Medições Luminescentes/métodos , Gases/análise , Ítrio
17.
J Am Chem Soc ; 129(6): 1541-52, 2007 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-17243675

RESUMO

Ordered titanium dioxide (TiO2) films have received increasing attention because of their great potential in photocatalysis, energy conversion, and electrooptical techniques. Such films are often fabricated as coatings on various substrates such as silicon or a variety of polymers. Liquid-phase deposition (LPD) of TiO2 films is especially promising for organic substrates due to its very mild reaction conditions. In the present paper, LPD is conducted on a wettability-patterned polypropylene surface to fabricate positive and negative TiO2 micropatterns. A thin layer of ammonium persulfate in an aqueous solution was sandwiched between two biaxially oriented polypropylene (BOPP) films, and a photomask was employed to control the irradiation region. Within a short time interval, a high hydrophilicity could be obtained on the irradiation region, and an effective wettability contrast between the irradiated and unirradiated regions could be created to further induce the formation of two types of TiO2 micropatterns. Up until now, most approaches for micropatterning have been based on self-assembled monolayers on surfaces of gold (or other noble metals), silicon, and various polyesters. With the present method, however, there is no longer any limitation in the type of substrate used. Our work demonstrates that an anatase TiO2 film could be selectively deposited on a hydrophilic region, giving rise to a positive pattern with significant bonding strength and good line edge acuity, providing an effective solution toward the microfabrication on various inert polymer substrates. More surprisingly, we find, for the first time, that TiO2 could also be selectively retained on a hydrophobic region to form a negative pattern by simply adjusting the reaction conditions. Further analysis of the mechanism shows that, independent of the deposition conditions, the TiO2 deposition pattern changes gradually, from being initially negative to becoming positive as the deposition time increases. The surface functionality changes (from sulfate to hydroxyl groups) during the deposition, and the resulting difference in the affinity for TiO2 is used to interpret this negative-to-positive pattern change. Such negative patterns refute the conventional opinion that only hydrophilic regions favor the formation of TiO2 films and could be used to fabricate large areas (mm2) of interconnected TiO2 micronetworks. Such networks are difficult to obtain by conventional metallic masks, and the present method is expected to provide new strategies in the fabrication of flexible photomasks and macro/mesoporous TiO2 films. An example is given wherein a patterned photografting of poly(acrylic acid) on the surface of BOPP is achieved by using such a polymer-based photomask. The innovativeness of this method arises from its ability to provide negative patterning, whereas present related approaches have been found only to give positive patterns from an equivalent photomask. Unlike complex photolithography procedures, our irradiation and patterning process does not require the use of positive or negative photoresists, and should thus prove to be a simple, fast, and low-cost method.

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