Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
Macromol Rapid Commun ; 44(1): e2200297, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35621302

RESUMO

Molecules based on benzimidazolone-dioxazine are known as blue/violet pigments and have been commercialized for decades. However, unfavorable solubility limits the application of these structures as building blocks of conjugated polymers despite their low band gaps. Herein, a series of donor-acceptor conjugated polymers containing soluble benzimidazolone-dioxazine structures as the acceptors and oligothiophene as donors are synthesized and investigated. With increasing numbers of thiophene rings, the steric hindrance diminishes and high molecular weight polymers can be achieved, leading to an improved performance in organic field effect transistor devices. The hole mobility of polymers with three to six thiophene units is in the order of 10-1 cm2 V-1 s -1 . Among all the polymers, polymer P3 with three thiophene units between benzimidazolone-dioxazine structures shows the best hole mobility of 0.4 cm2 V-1 s -1 . Grazing-incidence wide-angle X-ray scattering results reveal that the high mobility of organic field-effect transistors (OFETs) can be accredited by matched donor-acceptor packing in the solid thin films.


Assuntos
Bandagens , Benzimidazóis , Polímeros , Tiofenos
2.
Int J Mol Sci ; 24(4)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36834609

RESUMO

The DEAD-box proteins, one family of RNA-binding proteins (RBPs), participate in post-transcriptional regulation of gene expression with multiple aspects. Among them, DDX6 is an essential component of the cytoplasmic RNA processing body (P-body) and is involved in translational repression, miRNA-meditated gene silencing, and RNA decay. In addition to the cytoplasmic function, DDX6 is also present in the nucleus, but the nuclear function remains unknown. To decipher the potential role of DDX6 in the nucleus, we performed mass spectrometry analysis of immunoprecipitated DDX6 from a HeLa nuclear extract. We found that adenosine deaminases that act on RNA 1 (ADAR1) interact with DDX6 in the nucleus. Utilizing our newly developed dual-fluorescence reporter assay, we elucidated the DDX6 function as negative regulators in cellular ADAR1p110 and ADAR2. In addition, depletion of DDX6 and ADARs results in the opposite effect on facilitation of RA-induced differentiation of neuronal lineage cells. Our data suggest the impact of DDX6 in regulation of the cellular RNA editing level, thus contributing to differentiation in the neuronal cell model.


Assuntos
RNA Helicases DEAD-box , MicroRNAs , Humanos , RNA Helicases DEAD-box/metabolismo , Proteínas Proto-Oncogênicas/genética , MicroRNAs/genética , Regulação da Expressão Gênica , Diferenciação Celular , Adenosina Desaminase/metabolismo
3.
J Am Chem Soc ; 144(21): 9390-9398, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35587710

RESUMO

The shapeshifting behavior for synthetic matters was found at either the molecular or supramolecular level, but the connection between shapeshifting at the two hierarchical levels remains missing. In this study, an 8-arm star giant molecule, NPOSS, was synthesized to connect the molecular and supramolecular shapeshifting. Controlling the conditions of bulk self-assembly allowed us to bring NPOSS into three different Ostwald's stages of nucleation. The high conformational flexibility of NPOSS facilitates molecular shapeshifting and allows NPOSS to take the discotic, rod-like and star-like geometries in different Ostwald's stages. Simultaneous changes in the supramolecular scaffolds were observed as the discotic, rod-like and star-like NPOSS molecules self-assembled into the supramolecular scaffolds of 1D columns, 2D lamellae, and 3D networks, respectively. These changes in the hierarchical structures also affect the CO2 affinity of NPOSS. Therefore, the connection between the molecular/supramolecular shapeshifting and the structure-driven property changes of NPOSS were established by taking advantage of the high conformational freedom of the 8-arm star giant molecule and its diverse self-assembly pathways leading to the different Ostwald's stages.


Assuntos
Conformação Molecular
4.
Biomedicines ; 11(10)2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37893043

RESUMO

The dysregulated expression of cyclin genes can lead to the uncontrolled proliferation of cancer cells. Histone demethylase Jumonji-C domain-containing protein 5 (KDM8, JMJD5) and cyclin A1 (CCNA1) are pivotal in cell cycle progression. A promising candidate for augmenting cancer treatment is Allyl isothiocyanate (AITC), a natural dietary chemotherapeutic and epigenetic modulator. This study aimed to investigate AITC's impact on the KDM8/CCNA1 axis to elucidate its role in oral squamous cell carcinoma (OSCC) tumorigenesis. The expression of KDM8 and CCNA1 was assessed using a tissue microarray (TMA) immunohistochemistry (IHC) assay. In vitro experiments with OSCC cell lines and in vivo experiments with patient-derived tumor xenograft (PDTX) and SAS subcutaneous xenograft tumor models were conducted to explore AITC's effects on their expression and cell proliferation. The results showed elevated KDM8 and CCNA1 levels in the OSCC patient samples. AITC exhibited inhibitory effects on OSCC tumor growth in vitro and in vivo. Additionally, AITC downregulated KDM8 and CCNA1 expression while inducing histone H3K36me2 expression in oral cancer cells. These findings underscore AITC's remarkable anticancer properties against oral cancer, highlighting its potential as a therapeutic option for oral cancer treatment by disrupting the cell cycle by targeting the KDM8/CCNA1 axis.

5.
Nanoscale ; 13(7): 4295-4300, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33595571

RESUMO

Giant shape amphiphiles (GSA) are giant molecules made with nano-building blocks that have distinct shapes. The incompatible packing behaviors of the nano-building blocks of GSA could create cavities within certain conformers of the GSA, but the host-guest chemistry of GSA has not been explored yet. In this study, POSS-PDI-POSS (PPP), which is made by connecting two nano-cubes, isobutyl-polyhedral oligomeric silsesquioxanes (POSS), to a conjugated π-conjugated core, perylene diimide (PDI), is demonstrated as a novel acyclic synthetic host. In its bent conformer, PPP shows a cavity next to its PDI core. Via forming host-guest complexes with π-conjugated guests such as pyrene and perylene, PPP is found to transform from the bent-conformer into the extended-conformer, creating the steric features to accommodate guest molecules. Subsequent thermal annealing of the host-guest complexes removes the π-conjugated guests and restores the bent conformation and photophysical properties of PPP, which verifies that PPP, as a novel acyclic host, is capable of dynamic host-guest assembly. Moreover, the results prove that cavities at the molecular level can be created by connecting nano-building blocks with distinct shapes. This finding may inspire developments in the host-guest chemistry of GSA and nanomaterial innovation.

6.
Nanoscale Adv ; 3(1): 173-176, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36131877

RESUMO

Evolving synthetic molecules toward complex structures is a major goal in supramolecular chemistry. Increasing the number of clips in a unimolecular multi-clip (UMC), although vital to elevate the complexity of supramolecular architectures, often prevents the UMC from forming host-guest complexes in the bulk phase. To overcome this difficulty, adaptive chemistry was applied to develop a novel adaptive unimolecular quaternary clip (Q-clip). The Q-clip is intrinsically amorphous, but self-organizes with exclusively 4 eq. of allosteric activators (NDI) to form the Q-clip : NDI4 complexes and a supramolecular lamellar structure in the bulk. The adaptive assembly is fast and allows us to locate the adaptive assembly area of Q-clip : NDI4 complexes in the amorphous Q-clip film. Our results provide new insights into the design of adaptive UMCs for the evolution toward complex structures and supramolecular functional materials.

7.
J Chin Med Assoc ; 80(4): 227-232, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28169209

RESUMO

BACKGROUND: Hospice care has been part of the Taiwan health-care system for 20 years. Detailed information on the place of death for terminal cancer patients is lacking. Impending death discharge (IDD) is unique in Taiwan, and our study aims to compare IDD with in-hospice death among terminal cancer patients under hospice care. METHODS: This retrospective study used claims data of decedents of cancer from the National Health Insurance Research Database of Taiwan from 2007 to 2010. RESULTS: Of the 22,720 cancer decedents enrolled, 6316 had claims data marked with IDD and 16,404 with in-hospice death. Those with IDD were older; had a shorter hospice stay; and higher rates of gastrointestinal, peritoneal, and pulmonary cancers. The mean daily health-care expenditure was higher in those with IDD, however, the total expenditure of terminal hospice admission was lower than those dying in hospices. Patients who were treated at public hospitals had a higher rate of in-hospice death than those treated at private hospitals. Patients with IDD were positively correlated with increasing age and shorter hospice stay. Patients with IDD were positively correlated with private hospitals, especially religious corporation-based hospitals. Male sex, oropharyngeal cancer, bone/connective/breast cancers, and secondary/metastatic cancers were negatively correlated with IDD. CONCLUSION: Patients with IDD have characteristics distinct from those dying in hospices. Advanced age and short hospice stays were common in those with IDD, and in-depth investigations were needed. As a unique predying process in Taiwan, relevant health-care issues regarding IDD are warranted for further investigations.


Assuntos
Cuidados Paliativos na Terminalidade da Vida , Neoplasias/terapia , Alta do Paciente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Taiwan
8.
Nanoscale ; 8(3): 1280-7, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26677004

RESUMO

New silicon based anodic materials in lithium ion batteries (Si-based LIBs) have been developed worldwide to overcome capacity decay during the lithiation/delithiation process. In this study, a composite of Si nanoparticles coated with 5-sulfoisophthalic acid (SPA) doped polyaniline (core/shell SiNPs@PANi/SPA) was prepared and applied as an anode material for LIB applications. The detailed structure of the core/shell SiNPs@PANi/SPA composite was characterized using high-resolution scanning electron microscopy before and after charging/discharging. The electrochemical measurements showed that the SiNPs@PANi/SPA anode exhibited a high capacity of 925 mA h g(-1) and high coulombic efficiency (99.6%) after long-term cycling (1000 cycles). Overall results indicated that the SPA doped polyaniline served as a conductive matrix to improve electrical contact and to provide an adhesive force in Si-based LIBs. Our approach opens a route for the design of efficient silicon nanocomposites for LIB applications.

9.
Stem Cell Res Ther ; 5(2): 52, 2014 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24739572

RESUMO

INTRODUCTION: Gingiva-derived mesenchymal stem cells (GMSCs) have recently been harvested and applied for rebuilding lost periodontal tissue. Enamel matrix derivative (EMD) has been used for periodontal regeneration and the formation of new cementum with inserting collagen fibers; however, alveolar bone formation is minimal. Recently, EMD has been shown to enhance the proliferation and mineralization of human bone marrow mesenchymal stem cells. Because the gingival flap is the major component to cover the surgical wound, the effects of EMD on the proliferation and mineralization of GMSCs were evaluated in the present study. METHODS: After single cell suspension, the GMSCs were isolated from the connective tissues of human gingiva. The colony forming unit assay of the isolated GMSCs was measured. The expression of stem cell markers was examined by flow cytometry. The cellular telomerase activity was identified by polymerase chain reaction (PCR). The osteogenic, adipogenic and neural differentiations of the GMSCs were further examined. The cell proliferation was determined by MTS assay, while the expression of mRNA and protein for mineralization (including core binding factor alpha, cbfα-1; alkaline phosphatase, ALP; and osteocalcin, OC; ameloblastin, AMBN) were analyzed by real time-PCR, enzyme activity and confocal laser scanning microscopy. RESULTS: The cell colonies could be easily identified and the colony forming rates and the telomerase activities increased after passaging. The GMSCs expressed high levels of surface markers for CD73, CD90, and CD105, but showed low expression of STRO-1. Osteogenic, adipogenic and neural differentiations were successfully induced. The proliferation of GMSCs was increased after EMD treatment. ALP mRNA was significantly augmented by treating with EMD for 3 hours, whereas AMBN mRNA was significantly increased at 6 hours after EMD treatment. The gene expression of OC was enhanced at the dose of 100 µg/ml EMD at day 3. Increased protein expression for cbfα-1 at day 3, for ALP at day 5 and 7, and for OC at week 4 after the EMD treatments were observed. CONCLUSIONS: Human GMSCs could be successfully isolated and identified. EMD treatments not only induced the proliferation of GMSCs but also enhanced their osteogenic differentiation after induction.


Assuntos
Osso e Ossos/citologia , Esmalte Dentário/metabolismo , Gengiva/citologia , Células-Tronco Mesenquimais/citologia , Osteogênese/efeitos dos fármacos , Osso e Ossos/metabolismo , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Gengiva/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo
10.
IEEE Trans Syst Man Cybern B Cybern ; 42(1): 150-62, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21878416

RESUMO

In this paper, we propose a novel possibilistic fuzzy matching strategy with invariant properties, which can provide a robust and effective matching scheme for two sets of iris feature points. In addition, the nonlinear normalization model is adopted to provide more accurate position before matching. Moreover, an effective iris segmentation method is proposed to refine the detected inner and outer boundaries to smooth curves. For feature extraction, the Gabor filters are adopted to detect the local feature points from the segmented iris image in the Cartesian coordinate system and to generate a rotation-invariant descriptor for each detected point. After that, the proposed matching algorithm is used to compute a similarity score for two sets of feature points from a pair of iris images. The experimental results show that the performance of our system is better than those of the systems based on the local features and is comparable to those of the typical systems.


Assuntos
Algoritmos , Inteligência Artificial , Biometria/métodos , Lógica Fuzzy , Interpretação de Imagem Assistida por Computador/métodos , Iris/anatomia & histologia , Reconhecimento Automatizado de Padrão/métodos , Retinoscopia/métodos , Técnica de Subtração , Humanos
11.
Electrophoresis ; 27(23): 4674-81, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17080486

RESUMO

In this study, poly(styrene-divinylbenzene-vinylsulfonic acid) monolithic columns, prepared by singlestep in situ polymerization, were first used as separation columns for CEC in which vinylsulfonic acid was employed as the charge-bearing monomer. The effects of the polymerization conditions (compositions of monomer and porogenic solvent, and polymerization time) on the chromatographic property of the polystyrene-based monolithic column were examined. Furthermore, an increase in water content of the porogenic solvent markedly altered the retention behaviors of these analytes, where the monolithic column was able to be produced in a higher ratio of vinylsulfonic acid. Finally, the study demonstrated that acidic analytes could be successfully separated by the polystyrene-based monolithic column under an acidic mobile phase.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/instrumentação , Cromatografia Capilar Eletrocinética Micelar/métodos , Poliestirenos/química , Polivinil/química , Ácidos Sulfônicos/química
12.
J Sep Sci ; 29(13): 2038-48, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17017017

RESUMO

In this study, a series of poly(styrene-divinylbenzene-methacrylic acid) monolithic capillaries was used as the separation column of CEC for the analyses of parabens in commercial pharmaceutical and cosmetic products. The results showed that the chromatographic characteristics of these analytes were strongly affected by the preparation condition of the monolithic column including monomer content, porogenic solvent composition, and polymerization time. Baseline separations were markedly sped up by lowering the polymerization time without any obvious loss of resolution. Furthermore, mobile-phase composition (pH, ACN, and electrolyte concentration) was also able to effectively improve the separation behavior. Similar to the influence of lowering the polymerization time, retention times for all analytes were significantly shortened in the CEC method by decreasing the electrolyte concentration in the mobile phase.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA