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1.
Front Oncol ; 13: 1295613, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38045004

RESUMO

How the function of the JMJD2D epigenetic regulator is regulated or whether it plays a role in prostate cancer has remained elusive. We found that JMJD2D was overexpressed in prostate tumors, stimulated prostate cancer cell growth and became methylated by SET7/9 on K427. Mutation of this lysine residue in JMJD2D reduced the ability of DU145 prostate cancer cells to grow, invade and form tumors and elicited extensive transcriptomic changes. This included downregulation of CBLC, a ubiquitin ligase gene with hitherto unknown functions in prostate cancer, and upregulation of PLAGL1, a transcription factor with reported tumor suppressive characteristics in the prostate. Bioinformatic analyses indicated that CBLC expression was elevated in prostate tumors. Further, downregulation of CBLC largely phenocopied the effects of the K427 mutation on DU145 cells. In sum, these data have unveiled a novel mode of regulation of JMJD2D through lysine methylation, illustrated how this can affect oncogenic properties by influencing expression of the CBLC gene, and established a pro-tumorigenic role for CBLC in the prostate. A corollary is that JMJD2D and CBLC inhibitors could have therapeutic benefits in the treatment of prostate and possibly other cancers.

2.
JCI Insight ; 8(20)2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37870957

RESUMO

The histone demethylase JMJD2A/KDM4A facilitates prostate cancer development, yet how JMJD2A function is regulated has remained elusive. Here, we demonstrate that SET7/9-mediated methylation on 6 lysine residues modulated JMJD2A. Joint mutation of these lysine residues suppressed JMJD2A's ability to stimulate the MMP1 matrix metallopeptidase promoter upon recruitment by the ETV1 transcription factor. Mutation of just 3 methylation sites (K505, K506, and K507) to arginine residues (3xR mutation) was sufficient to maximally reduce JMJD2A transcriptional activity and also decreased its binding to ETV1. Introduction of the 3xR mutation into DU145 prostate cancer cells reduced in vitro growth and invasion and also severely compromised tumorigenesis. Consistently, the 3xR genotype caused transcriptome changes related to cell proliferation and invasion pathways, including downregulation of MMP1 and the NPM3 nucleophosmin/nucleoplasmin gene. NPM3 downregulation phenocopied and its overexpression rescued, to a large degree, the 3xR mutation in DU145 cells, suggesting that NPM3 was a seminal downstream effector of methylated JMJD2A. Moreover, we found that NPM3 was overexpressed in prostate cancer and might be indicative of disease aggressiveness. SET7/9-mediated lysine methylation of JMJD2A may aggravate prostate tumorigenesis in a manner dependent on NPM3, implying that the SET7/9→JMJD2A→NPM3 axis could be targeted for therapy.


Assuntos
Histona Desmetilases , Histona Desmetilases com o Domínio Jumonji , Neoplasias da Próstata , Humanos , Masculino , Carcinogênese , Transformação Celular Neoplásica , Histona Desmetilases/genética , Histona Desmetilases com o Domínio Jumonji/genética , Histona Desmetilases com o Domínio Jumonji/metabolismo , Lisina/metabolismo , Metaloproteinase 1 da Matriz/metabolismo , Metilação , Neoplasias da Próstata/genética
3.
Int J Biochem Mol Biol ; 14(6): 101-115, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38213775

RESUMO

OBJECTIVES: Jumonji C domain-containing (JMJD) 2B (JMJD2B) is a transcriptional cofactor and histone demethylase that is involved in prostate cancer formation. However, how its function is regulated by posttranslational modification has remained elusive. Hence, we examined if JMJD2B would be regulated by lysine methylation. METHODS: Through in vitro methylation assays and Western blotting with methyl-lysine specific antibodies, we analyzed lysine methylation within JMJD2B. Identified methylated lysine residues were mutated to arginine residues and the respective impact on JMJD2B transcriptional activity measured with a reporter gene assay in human LNCaP prostate cancer cells. RESULTS: We discovered that JMJD2B is methylated on up to six different lysine residues. Further, we identified the suppressor of variegation 3-9/enhancer of zeste/trithorax (SET) domain-containing protein 7/9 (SET7/9) as the methyltransferase being responsible for this posttranslational modification. Mutating the methylation sites in JMJD2B to arginine residues led to diminished coactivation of the Ju-nana (JUN) transcription factor, which is a known oncogenic protein in prostate tumors. In contrast, methylation of JMJD2B had no impact on its ability to coactivate another transcription factor associated with prostate cancer, the DNA-binding protein E26 transformation-specific (ETS) variant 1 (ETV1). Consistent with a potential joint action of JMJD2B, SET7/9 and JUN in prostate cancer, the expression of JMJD2B in human prostate tumors was positively correlated with both SET7/9 and JUN levels. CONCLUSIONS: The identified SET7/9-mediated methylation of JMJD2B appears to impact its cooperation with selected interacting transcription factors in prostate cancer cells. Given the implicated roles of JMJD2B beyond prostate tumorigenesis, SET7/9-mediated methylation of JMJD2B possibly also influences the development of other cancers, while its impairment might have relevance for obesity or a global developmental delay that can be elicited by reduced JMJD2B activity.

4.
Polymers (Basel) ; 13(3)2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33513679

RESUMO

We synthesized medium-band-gap donor-acceptor (D-A) -type conjugated polymers (PBTZCZ-L and PBTZCZ-H) consisting of a benzotriazole building block as an acceptor and a carbazole unit as a donor. In comparison with the polymers, a small conjugated molecule (BTZCZ-2) was developed, and its structural, thermal, optical, and photovoltaic properties were investigated. The power conversion efficiency (PCE) of the BTZCZ-2-based solar cell devices was less than 0.5%, considerably lower than those of polymer-based devices with conventional device structures. However, inverted solar cell devices configured with glass/ITO/ZnO:PEIE/BTZCZ-2:PC71BM/MoO3/Ag showed a tremendously improved efficiency (PCE: 5.05%, Jsc: 9.95 mA/cm2, Voc: 0.89 V, and FF: 57.0%). We believe that this is attributed to high energy transfer and excellent film morphologies.

5.
Mitochondrial DNA B Resour ; 5(1): 1015-1016, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33366853

RESUMO

The completed chloroplast genome of Gastrodia elata Blume (G. elata) from Korea was determined in this study. The cpDNA is 35,230 bp in length and lacked the large and small single copy (LSC and SSC) regions, due to the lost inverted repeat (IR). The overall AT content is 73.30%, and the cpDNA contains 20 protein-coding genes, 5 tRNA genes, and 3 rRNA genes. Remarkably, the Korean G. elata cp genome was 74 bp smaller than that of the Chinese G. elata. It revealed substantial sequence variants 495 SNPs and 75 InDels between the two G. elata genomes.

6.
Sci Rep ; 9(1): 13161, 2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511588

RESUMO

Nut weight is one of the most important traits that can affect a chestnut grower's returns. Due to the long juvenile phase of chestnut trees, the selection of desired characteristics at early developmental stages represents a major challenge for chestnut breeding. In this study, we identified single nucleotide polymorphisms (SNPs) in transcriptomic regions, which were significantly associated with nut weight in chestnuts (Castanea crenata), using a genome-wide association study (GWAS). RNA-sequencing (RNA-seq) data were generated from large and small nut-bearing trees, using an Illumina HiSeq. 2000 system, and 3,271,142 SNPs were identified. A total of 21 putative SNPs were significantly associated with chestnut weight (false discovery rate [FDR] < 10-5), based on further analyses. We also applied five machine learning (ML) algorithms, support vector machine (SVM), C5.0, k-nearest neighbour (k-NN), partial least squares (PLS), and random forest (RF), using the 21 SNPs to predict the nut weights of a second population. The average accuracy of the ML algorithms for the prediction of chestnut weights was greater than 68%. Taken together, we suggest that these SNPs have the potential to be used during marker-assisted selection to facilitate the breeding of large chestnut-bearing varieties.


Assuntos
Fagaceae/genética , Estudo de Associação Genômica Ampla/métodos , Nozes/genética , Polimorfismo de Nucleotídeo Único , Transcriptoma/genética , Fagaceae/classificação , Genótipo , Aprendizado de Máquina , Fenótipo , Melhoramento Vegetal , Análise de Sequência de RNA/métodos , Especificidade da Espécie , Máquina de Vetores de Suporte
7.
Mitochondrial DNA B Resour ; 4(2): 3864-3865, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-33366224

RESUMO

The complete chloroplast genome sequence of Castanea crenata was sequenced and assembled using PacBio Sequel data. The cpDNA was 160,787 bp in length, containing a pair of inverted repeats (IRs) of 25,654 bp each separated by a large and small single copy (LSC and SSC) regions of 90,645 bp and 18,836 bp, respectively. The cpDNA contained 102 genes, including 65 protein-coding genes, 8 ribosomal RNA genes and 37 transfer RNA genes. Phylogenetic analysis indicated that C. crenata was closest to C. pumila var. pumila, which is known as a typical variety of American chinquapin or dwarf chestnut.

8.
Oncotarget ; 8(58): 98495-98508, 2017 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-29228705

RESUMO

The Hippo pathway is an evolutionarily conserved signaling pathway that regulates proliferation and apoptosis to control organ size during developmental growth. Yes-associated protein 1 (YAP1), the terminal effector of the Hippo pathway, is a transcriptional co-activator and a potent growth promoter that has emerged as a critical oncogene. Overexpression of YAP1 has been implicated in promoting resistance to chemo-, radiation and targeted therapy in various cancers. However, the role of YAP1 in radioresistance in triple-negative breast cancer (TNBC) is currently unknown. We evaluated the role of YAP1 in radioresistance in TNBC in vitro, using two approaches to inhibit YAP1: 1) genetic inhibition by YAP1 specific shRNA or siRNA, and 2) pharmacological inhibition by using the small molecule inhibitor, verteporfin that prevents YAP1 transcriptional activity. Our findings demonstrate that both genetic and pharmacological inhibition of YAP1 sensitizes TNBC cells to radiation by inhibiting the EGFR/PI3K/AKT signaling axis and causing an increased accumulation of DNA damage. Our results reveal that YAP1 activation exerts a protective role for TNBC cells in radiotherapy and represents a pharmacological target to enhance the anti-tumor effects of DNA damaging modalities in the treatment of TNBC.

9.
Oncol Rep ; 35(6): 3679-88, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27109047

RESUMO

ERG (ETS-related gene) is a member of the ETS (erythroblast transformation-specific) family of transcription factors. Overexpression of the ERG transcription factor is observed in half of all prostate tumors and is an underlying cause of this disease. However, the mechanisms involved in the functions of ERG are still not fully understood. In the present study, we showed that ERG can directly bind to KDM4A (also known as JMJD2A), a histone demethylase that particularly demethylates lysine 9 on histone H3. ERG and KDM4A cooperated in upregulating the promoter of Yes-associated protein 1 (YAP1), a downstream effector in the Hippo signaling pathway and crucial growth regulator. Multiple ERG binding sites within the human YAP1 gene promoter were identified and their impact on transcription was determined through mutational analysis. Furthermore, we found that ERG expression reduced histone H3 lysine 9 trimethylation at the YAP1 gene promoter, consistent with its epigenetic regulation through the ERG interaction partner, KDM4A. Finally, downregulation of YAP1 phenocopied the growth-retarding effect of ERG or KDM4A depletion in human VCaP prostate cancer cells. Collectively, these results elucidated a novel mechanism - ERG promotes prostate tumorigenesis together with KDM4A through the upregulation of YAP1. A corollary is that KDM4A as well as YAP1 inhibitors may prove beneficial for the therapy of ERG-overexpressing prostate tumors.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Proteínas Adaptadoras de Transdução de Sinal/genética , Histona Desmetilases com o Domínio Jumonji/metabolismo , Fosfoproteínas/biossíntese , Fosfoproteínas/genética , Regiões Promotoras Genéticas/genética , Neoplasias da Próstata/patologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Proteínas de Ligação a DNA , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Histona Desmetilases com o Domínio Jumonji/genética , Masculino , Ligação Proteica , Interferência de RNA , RNA Interferente Pequeno/genética , Fatores de Transcrição , Regulador Transcricional ERG/genética , Regulador Transcricional ERG/metabolismo , Proteínas de Sinalização YAP
10.
J Clin Invest ; 126(2): 706-20, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26731476

RESUMO

Histone demethylase upregulation has been observed in human cancers, yet it is unknown whether this is a bystander event or a driver of tumorigenesis. We found that overexpression of lysine-specific demethylase 4A (KDM4A, also known as JMJD2A) was positively correlated with Gleason score and metastasis in human prostate tumors. Overexpression of JMJD2A resulted in the development of prostatic intraepithelial neoplasia in mice, demonstrating that JMJD2A can initiate prostate cancer development. Moreover, combined overexpression of JMJD2A and the ETS transcription factor ETV1, a JMJD2A-binding protein, resulted in prostate carcinoma formation in mice haplodeficient for the phosphatase and tensin homolog (Pten) tumor-suppressor gene. Additionally, JMJD2A cooperated with ETV1 to increase expression of yes associated protein 1 (YAP1), a Hippo pathway component that itself was associated with prostate tumor aggressiveness. ETV1 facilitated the recruitment of JMJD2A to the YAP1 promoter, leading to changes in histone lysine methylation in a human prostate cancer cell line. Further, YAP1 expression largely rescued the growth inhibitory effects of JMJD2A depletion in prostate cancer cells, indicating that YAP1 is a downstream effector of JMJD2A. Taken together, these data reveal a JMJD2A/ETV1/YAP1 axis that promotes prostate cancer initiation and that may be a suitable target for therapeutic inhibition.


Assuntos
Transformação Celular Neoplásica/metabolismo , Proteínas de Ligação a DNA/metabolismo , Histona Desmetilases/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias da Próstata/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Proteínas de Ligação a DNA/genética , Feminino , Histona Desmetilases/genética , Humanos , Histona Desmetilases com o Domínio Jumonji/genética , Masculino , Camundongos , Camundongos Transgênicos , Proteínas de Neoplasias/genética , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Neoplasias da Próstata/genética , Fatores de Transcrição/genética , Proteínas de Sinalização YAP
11.
Int J Clin Exp Med ; 9(6): 10123-10134, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28883898

RESUMO

PSMD10, also known as gankyrin, is associated with the proteasome and has been shown to be an oncoprotein in the liver. Here, we report that PSMD10 expression is stimulated by the histone demethylase JMJD2A/KDM4A and its interaction partner, the ETV1 transcription factor, in LNCaP prostate cancer cells. Global analysis of expression patterns revealed that PSMD10 mRNA levels are positively correlated with those of both JMJD2A and ETV1. In human prostate tumors, PSMD10 is highly overexpressed at the protein level and correlates with JMJD2A overexpression; further, PSMD10 expression is enhanced in the prostates of transgenic JMJD2A mice. Moreover, PSMD10 is particularly overexpressed in high Gleason score prostate tumors. Downregulation of PSMD10 in LNCaP prostate cancer cells impaired their growth, indicating that PSMD10 may exert a pro-oncogenic function in the prostate. Lastly, we observed that PSMD10 expression is correlated to YAP1, a component of the Hippo signaling pathway and whose gene promoter is regulated by JMJD2A, and that PSMD10 can cooperate with YAP1 in stimulating LNCaP cell growth. Altogether, these data indicate that PSMD10 is a novel downstream effector of JMJD2A and suggest that inhibition of the JMJD2A histone demethylase by small molecule drugs may be effective to curtail the oncogenic activity of PSMD10 in various PSMD10-overexpressing tumors.

12.
Macromol Rapid Commun ; 36(11): 943-58, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25820642

RESUMO

Dipolar chromophores consisting of electron donor (D) and electron acceptor (A) groups connected through a conjugated π-bridge have been actively studied and integrated in optoelectronic and electronic devices. Generally, such π-conjugated molecules provide substantial delocalization of π-electrons over the molecules. Here, a brief overview of recent research on D-π-A dipolar chromophores including their syntheses and several promising applications is reported, especially in nonlinear optical devices and organic photovoltaics. Structure/property relationships are discussed in order to exploit the potentials by tuning the π-electron density, polarizability, and HOMO-LUMO band gap of the chromophores. Some of the examples may well set the stage for chip-scale integration of optoelectronics as well as the realization of an important array of new device technologies.


Assuntos
Eletrônica , Carbocianinas/química , Elétrons , Porfirinas/química , Teoria Quântica , Energia Solar , Tiofenos/química
13.
Am J Transl Res ; 6(3): 236-47, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24936217

RESUMO

Colon tumors are a major cause of cancer death, yet their molecular intricacies are not fully understood. We demonstrate that the histone demethylases JMJD2A, JMJD2B and JMJD2C are overexpressed in colon cancer cell lines, whereas another related protein, JMJD2D, is not. Interestingly, despite their high homology, the intracellular localization of JMJD2A-C is different in colon and other cancer cells, with JMJD2A being present comparably in the cytoplasm and nucleus, JMJD2B more prevalent in the nucleus and JMJD2C strongly associated with chromatin. This suggests that each of these three proteins performs different, non-redundant functions. Moreover, we show that JMJD2C (also called KDM4C) forms complexes with ß-catenin, an oncoprotein whose overexpression is crucial for the development of most colonic tumors. In addition, JMJD2C downregulation reduced both growth and clonogenic capacity of HCT-116 colon cancer cells. Further, JMJD2C was required for efficient expression of the growth stimulatory proteins FRA1 and cyclin D1 as well as the survival factor BCL2. Lastly, we identified derivatives of curcumin as in vitro inhibitors of JMJD2 enzymes, suggesting that these curcuminoids could be useful for decreasing JMJD2 activity in vivo. In conclusion, our data highlight that overexpression of JMJD2C confers a pro-growth effect on colon cancer cells and, therefore, its inhibition by curcuminoids or other small molecules could be beneficial as an adjuvant therapy for colon cancer patients.

14.
J Nanosci Nanotechnol ; 14(3): 2515-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24745256

RESUMO

In this paper, we report synthesis and characterization of alkylated fullerene derivatives for solution-processable organic thin film transistors and solar cells. Their physical, thermal, and semiconducting properties have been studied. Organic thin-film transistors fabricated from C60TH-Oc exhibit electron mobilities as high as 3.2 x 10(-2) cm2 V(-1) s(-1) with 32 V of a threshold voltage. The best power conversion efficiency (PCE) was observed in a layered structure P3HT:C60TH-Oc (PCE = 0.44%), which was a twice value of P3HT:C60TH-Dd (PCE = 0.23%).

15.
Int J Oncol ; 44(4): 1341-8, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24481461

RESUMO

The linchpin of colorectal cancer is the oncoprotein and transcriptional cofactor ß-catenin, whose overexpression is causative for the neoplastic transformation of colon cells. However, the molecular details of ß-catenin dependent gene transcription in cancer cells are still not comprehensively explored. Here, we show that the histone demethylase KDM4B was upregulated in colon and rectal adenocarcinomas and required for efficient growth and clonogenic activity of human HT-29 colon cancer cells. Moreover, KDM4B formed complexes with ß-catenin in vitro and in vivo, which involved its central amino acids 353-740. In addition, KDM4B also interacted with the DNA-binding protein TCF4, which is the main factor recruiting ß-catenin to chromatin in the intestine. KDM4B downregulation resulted in reduced expression of the ß-catenin/TCF4 target genes JUN, MYC and Cyclin D1, all of which encode for oncoproteins. Collectively, our data indicate that KDM4B overexpression supports ß-catenin mediated gene transcription and thereby contributes to the genesis of colorectal tumors. Accordingly, inhibition of the KDM4B histone demethylase may represent a novel avenue of fighting colorectal cancer, one of the major causes of cancer death throughout the world.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Neoplasias do Colo/patologia , Histona Desmetilases com o Domínio Jumonji/genética , Fatores de Transcrição/metabolismo , beta Catenina/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Transformação Celular Neoplásica/genética , Ciclina D1/biossíntese , Proteínas de Ligação a DNA/metabolismo , Células HT29 , Humanos , Histona Desmetilases com o Domínio Jumonji/biossíntese , MAP Quinase Quinase 4/biossíntese , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-myc/biossíntese , Interferência de RNA , RNA Interferente Pequeno , Fator de Transcrição 4 , Transcrição Gênica , Ativação Transcricional , beta Catenina/biossíntese
16.
Artigo em Inglês | MEDLINE | ID: mdl-24051291

RESUMO

Vibrational properties of two fullerene derivatives: C60TZ-OT-5 (1) and C60TH-3HX (2) have been studied using infrared absorption and Raman scattering spectroscopies. Additionally, quantum chemical calculations of the equilibrium geometry and normal mode vibrations of these functionalized fullerenes were performed. It was stated that despite of distinct structural differences between the investigated molecules, their experimental spectra are quite similar and correspond well with the calculated ones. The orientation of the molecules in the Langmuir-Blodgett films was evaluated.


Assuntos
Fulerenos/química , Conformação Molecular , Análise Espectral Raman , Espectroscopia de Infravermelho com Transformada de Fourier , Vibração
17.
J Nanosci Nanotechnol ; 14(8): 6331-6, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25936114

RESUMO

We have synthesized and characterized a polyfluorene derivative composed of octyl-substituted thieno[3,2,-b]thiophene and 2,1,3-benzothiadiazole as an acceptor unit. The best power conversion efficiencies of the polymer were showed with 1.63% and 2.31% by using PCBM and PC71BM, respectively.

18.
J Nanosci Nanotechnol ; 12(5): 4269-73, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22852388

RESUMO

Here we report on the synthesis and characterization of anthracene derivative for solution processable organic field-effect transistors. The transistor devices with bottom-contact geometry provided a maximum field-effect mobility of 3.74 x 10(-4) cm2 V(-1) s(-1) as well as current on/off ratio of 5.05 x 10(4) and low threshold voltage. Structural information in the solid state is obtained by thermal analysis and two-dimensional wide angle X-ray scattering (2D-WAXS). From the 2D-WAXS, it is clear that the planes of anthracene rings and benzene ring of the molecule are different in solid state. We assume similar arrangement in the thin-film which limit the effective hopping and thus charge mobility.

19.
J Nanosci Nanotechnol ; 12(5): 4403-8, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22852417

RESUMO

New spirofluorene-based quadrupolar two-photon absorbing dyes having triphenylamine and N,N-dibutylaniline as electron donors at the end of molcules were designed and synthesized. The third-order nonlinear optical properties of these compounds were studied using a two-photon excited fluorescence method. They were found to have high two-photon absorption cross-section owing to extended conjugation of the spirofluorene moiety. The effect of varying the donor strength could be discerned by comparing the two compounds. They were successfully used as a photosensitizers for two-photon initiated polymerization of three-dimensional micro-objects.

20.
J Nanosci Nanotechnol ; 12(1): 730-6, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22524048

RESUMO

Crosslinkable NLO dendrimers based on azobenzene-type chromophores were synthesized by a Diels-Alder reaction. Their thermal and optical properties were investigated before and after poling at a high temperature. We found that the dendrimers retained good thermal stability up to 260 degrees C after curing at 130 degrees C for 10 min based on thermal analysis. Through in-situ poling and curing processes, the highest NLO activity of the dendrimers was d33 = 1.7 x 10(-6) esu at 1064 nm, which was determined by a Maker fringe experiment.


Assuntos
Reagentes de Ligações Cruzadas/química , Cristalização/métodos , Dendrímeros/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Dinâmica não Linear , Tamanho da Partícula , Propriedades de Superfície
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