| 1. |
- Ying, Wan, et al.
(författare)
-
Ordered Mesoporous Pd/Silica-Carbon as a Highly Active Heterogeneous Catalyst for Coupling Reaction of Chlorobenzene in Aqueous Media
- 2009
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:12, s. 4541-4550
-
Tidskriftsartikel (refereegranskat)abstract
- Heterogeneous palladium catalysts, which are supported on ordered mesoporous silica-carbon nanocomposites, have been applied in water-mediated coupling reactions of chlorobenzene without assistance of any phase-transfer catalysts. Characterization by XRD, TEM, N2 sorption, FT-IR, TG, XPS, and H2 chemisorption techniques reveals the highly ordered mesostructure, high surface areas (?345 m2/ g), large pore volumes (?0.46 cm3/g), uniform mesopore sizes (?6.3 nm), hybrid silicate and carbonaceous compositions, and a high dispersion of palladium nanoparticles (about 3 nm) in the mesopores. The catalyst exhibits a high yield for trans-stilbene (?60%) in the Heck coupling reaction of chlorobenzene and styrene at 100 ‹C and for biphenyl (46%) in the Ullmann coupling reaction of chlorobenzene at 30 ‹C, using water as a solvent. When substituted aryl chlorides (hydroxyl, methoxyl, and methyl) are involved in the Ullmann reaction, the yields of symmetrical substituted biphenyl are also higher than 44% (this value reaches 86% for the coupling reaction of 4-chlorophenol) at a low temperature of 30 ‹C. This heterogeneous catalyst is stable, which shows negligible metal leaching, and can be reused more than 20 times. For comparison, the catalytic activities for Pd catalysts supported on pure mesoporous polymeric, carbonaceous, and silicate frameworks are also investigated. The results clearly indicate that the pore wall nature shows great influence on the dispersion of metallic Pd species and, in turn, the catalytic performance.
|
|
| 2. |
- Cheng, Dantong, et al.
(författare)
-
MicroRNA-20a-5p promotes colorectal cancer invasion and metastasis by downregulating Smad4
- 2016
-
Ingår i: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 7:29, s. 45199-45213
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Tumor metastasis is one of the leading causes of poor prognosis for colorectal cancer (CRC) patients. Loss of Smad4 contributes to aggression process in many human cancers. However, the underlying precise mechanism of aberrant Smad4 expression in CRC development is still little known. Results: miR-20a-5p negatively regulated Smad4 by directly targeting its 3UTR in human colorectal cancer cells. miR-20a-5p not only promoted CRC cells aggression capacity in vitro and liver metastasis in vivo, but also promoted the epithelial-to-mesenchymal transition process by downregulating Smad4 expression. In addition, tissue microarray analysis obtained from 544 CRC patients clinical characters showed that miR-20a-5p was upregulated in human CRC tissues, especially in the tissues with metastasis. High level of miR-20a-5p predicted poor prognosis in CRC patients. Methods: Five miRNA target prediction programs were applied to identify potential miRNA(s) that target(s) Smad4 in CRC. Luciferase reporter assay and transfection technique were used to validate the correlation between miR-20a-5p and Smad4 in CRC. Wound healing, transwell and tumorigenesis assays were used to explore the function of miR-20a-5p and Smad4 in CRC progression in vitro and in vivo. The association between miR-20a-5p expression and the prognosis of CRC patients was evaluated by Kaplan-Meier analysis and multivariate cox proportional hazard analyses based on tissue microarray data. Conclusions: miR-20a-5p, as an onco-miRNA, promoted the invasion and metastasis ability by suppressing Smad4 expression in CRC cells, and high miR-20a-5p predicted poor prognosis for CRC patients, providing a novel and promising therapeutic target in human colorectal cancer.
|
|
| 3. |
- Gu, Dong, et al.
(författare)
-
Growth of Single-Crystal Mesoporous Carbons with Im(3)over-barm Symmetry
- 2010
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 22:16, s. 4828-4833
-
Tidskriftsartikel (refereegranskat)abstract
- Highly ordered mesoporous carbon FDU-16 rhombic dodecahedral single crystals with body-centered cubic structure (space group Im (3) over barm) have been successfully synthesized by employing an organic-organic assembly of triblock copolymer Pluronic F127 (EO106PO70EO106) and phenol/formaldehyde resol in basic aqueous solution. Synthetic factors (including reaction time, temperature, and stirring rate) are explored for controlling the formation of rhombic dodecahedral single crystals. The optimal stirring rate and the reaction temperature are 300 +/- 10 rpm and similar to 66 degrees C, respectively. High-resolution scanning electron microscopy (HRSEM), scanning transmission electron microscopy (STEM), and ultramicrotomy are applied to study the fine structures of the carbon single crystals. The mesopores are arranged in body-centered cubic symmetry throughout the entire particle. Surface steps are clearly observed in the {110} surface, which suggests a layer-by-layer growth of the mesoporous carbon FDU-16 single crystals. Cryo-SEM results from the reactant solution confirm the formation of resol/F127 unit micelles, further supporting the layer-by-layer growth process. The mesoporous carbon FDU-16 single crystals grow up to the final size of 2-4 mu m within 2 days. These findings may have consequences for the growth mechanism of other carbon materials in aqueous solution; moreover, the high-quality single crystals also have potential applications in nanodevice technologies.
|
|
| 4. |
- Häffner, Sara Malekkhaiat, et al.
(författare)
-
Membrane Interactions of Virus-like Mesoporous Silica Nanoparticles
- 2021
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 15:4, s. 6787-6800
-
Tidskriftsartikel (refereegranskat)abstract
- In the present study, we investigated lipid membrane interactions of silica nanoparticles as carriers for the antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES). In doing so, smooth mesoporous nanoparticles were compared to virus-like mesoporous nanoparticles, characterized by a "spiky"external surface, as well as to nonporous silica nanoparticles. For this, we employed a combination of neutron reflectometry, ellipsometry, dynamic light scattering, and ζ-potential measurements for studies of bacteria-mimicking bilayers formed by palmitoyloleoylphosphatidylcholine/palmitoyloleoylphosphatidylglycerol. The results show that nanoparticle topography strongly influences membrane binding and destabilization. We found that virus-like particles are able to destabilize such lipid membranes, whereas the corresponding smooth silica nanoparticles are not. This effect of particle spikes becomes further accentuated after loading of such particles with LL-37. Thus, peptide-loaded virus-like nanoparticles displayed more pronounced membrane disruption than either peptide-loaded smooth nanoparticles or free LL-37. The structural basis of this was clarified by neutron reflectometry, demonstrating that the virus-like nanoparticles induce trans-membrane defects and promote incorporation of LL-37 throughout both bilayer leaflets. The relevance of such effects of particle spikes for bacterial membrane rupture was further demonstrated by confocal microscopy and live/dead assays on Escherichia coli bacteria. Taken together, these findings demonstrate that topography influences the interaction of nanoparticles with bacteria-mimicking lipid bilayers, both in the absence and presence of antimicrobial peptides, as well as with bacteria. The results also identify virus-like mesoporous nanoparticles as being of interest in the design of nanoparticles as delivery systems for antimicrobial peptides.
|
|
| 5. |
- Klingstedt, Miia, et al.
(författare)
-
Advanced electron microscopy characterization for pore structure of mesoporous materials; a study of FDU-16 and FDU-18
- 2011
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:35, s. 13664-13671
-
Tidskriftsartikel (refereegranskat)abstract
- We present a comprehensive analysis for pore structures of cage-type ordered mesoporous carbons (OMCs) using various electron microscopy techniques in addition to conventional nitrogen adsorption isotherm studies. The benefits and drawbacks of these techniques are evaluated, and it is shown that they are complementary to each other. Knowledge of the structural properties, pore sizes, and connectivity gives insight into the synthesis strategies and how they are affecting the material properties that are useful within the possible applications. Herein, focus is put on the two OMCs with Im (3) over barm and Fm (3) over barm symmetries specified by FDU-16 and FDU-18. The central techniques used in this study are high resolution scanning electron microscopy combined with cross-section polisher and three-dimensional reconstruction methods (electron tomography and electron crystallography) based on transmission electron microscopy observations.
|
|
| 6. |
- Mi, Yushuai, et al.
(författare)
-
Down-regulation of Barx2 predicts poor survival in colorectal cancer
- 2016
-
Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0006-291X .- 1090-2104. ; 478:1, s. 67-73
-
Tidskriftsartikel (refereegranskat)abstract
- Human BarH-like homeobox 2 (Barx2), a homeodomain factor of the Bar family, has an important role in controlling the expression of cell adhesion molecules and has been reported in an increasing array of tumor types except colorectal cancer (CRC). The purpose of the current study was to characterize the expression of Barx2 and assess the clinical significance of Barx2 in CRC. First, we analyzed the expression of Barx2 in two independent public datasets from Oncomine. Subsequently, we evaluated Barx2 mRNA and protein expression by quantitative real-time PCR and western blotting, respectively. It was determined that Barx2 expression was lower in tumor tissues than in adjacent non-tumorous colorectal tissues of CRC patients, consistent with results from the public datasets. Subsequently, a tissue microarray containing 196 CRC specimens was evaluated for Barx2 expression by immunohistochemical staining. It was found that low expression of Barx2 significantly correlated with TNM stage, AJCC stage, differentiation, and relapse in patients with CRC. Patients with lower levels of Barx2 expression showed reduced disease-free survival and overall survival. Furthermore, a trend toward shorter overall survival in the patient group with Barx2-negative tumors independent of advanced AJCC stage and poor differentiation was determined by Kaplan-Meier survival analysis. Based on univariate and multivariate analyses, Barx2 expression was an independent prognostic factor for determining CRC prognosis. Taken together, low Barx2 expression was associated with the progression of CRC and could serve as a potential independent prognostic biomarker for patients with CRC. (C) 2016 The Authors. Published by Elsevier Inc.
|
|
| 7. |
- Mi, Yushuai, et al.
(författare)
-
miR-181a-5p promotes the progression of gastric cancer via RASSF6-mediated MAPK signalling activation
- 2017
-
Ingår i: Cancer Letters. - : ELSEVIER IRELAND LTD. - 0304-3835 .- 1872-7980. ; 389, s. 11-22
-
Tidskriftsartikel (refereegranskat)abstract
- We previously discovered that Ras association domain family member 6 (RASSF6) was downregulated and predicted poor prognosis in GC patients. However, the mechanisms of the down regulation of RASSF6 in GC remained unclear. Increasing evidence indicates that dysregulation of microRNAs promotes the progression of cancer through the repression of tumour suppressors. Here, we identified miR-181a-5p as a novel regulator of RASSF6 in GC. Functionally, ectopic expression or silencing of miR-181a-5p, respectively, promoted or inhibited GC cell proliferation, colony formation and cell cycle transition, as well as enhanced or prevented the invasion, metastasis of GC cells and epithelial to mesenchymal transition of GC cells in vitro and in vivo. Molecularly, miR-181a-5p functioned as an onco-miRNA by activating the RASSF6-regulated MAKP pathway. Overexpression or silencing of RASSF6 could partially reverse the effects of the overexpression or repression of miR-181a-5p on GC progress caused by activation of the MAKP pathway in vitro and in vivo. Clinically, high miR-181a-5p expression predicted poor survival in GC patients, especially combined with low RASSF6 expression. Collectively, we identified miR-181a-5p as an onco-miRNA, which acts by directly repressing RASSF6 in GC. (C) 2017 The Authors. Published by Elsevier Ireland Ltd.
|
|
| 8. |
- Parra-Ortiz, Elisa, et al.
(författare)
-
Mesoporous silica as a matrix for photocatalytic titanium dioxide nanoparticles : lipid membrane interactions
- 2022
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 14:34, s. 12297-12312
-
Tidskriftsartikel (refereegranskat)abstract
- In the present study, we investigate the combined interaction of mesoporous silica (SiO2) and photocatalytic titanium dioxide (TiO2) nanoparticles with lipid membranes, using neutron reflectometry (NR), cryo-transmission electron microscopy (cryo-TEM), fluorescence oxidation assays, dynamic light scattering (DLS), and ζ-potential measurements. Based on DLS, TiO2 nanoparticles were found to display strongly improved colloidal stability at physiological pH of skin (pH 5.4) after incorporation into either smooth or spiky (“virus-like”) mesoporous silica nanoparticles at low pH, the latter demonstrated by cryo-TEM. At the same time, such matrix-bound TiO2 nanoparticles retain their ability to destabilize anionic bacteria-mimicking lipid membranes under UV-illumination. Quenching experiments indicated both hydroxyl and superoxide radicals to contribute to this, while NR showed that free TiO2 nanoparticles and TiO2 loaded into mesoporous silica nanoparticles induced comparable effects on supported lipid membranes, including membrane thinning, lipid removal, and formation of a partially disordered outer membrane leaflet. By comparing effects for smooth and virus-like mesoporous nanoparticles as matrices for TiO2 nanoparticles, the interplay between photocatalytic and direct membrane binding effects were elucidated. Taken together, the study outlines how photocatalytic nanoparticles can be readily incorporated into mesoporous silica nanoparticles for increased colloidal stability and yet retain most of their capacity for photocatalytic destabilization of lipid membranes, and with maintained mechanisms for oxidative membrane destabilization. As such, the study provides new mechanistic information to the widely employed, but poorly understood, practice of loading photocatalytic nanomaterials onto/into matrix materials for increased performance.
|
|
| 9. |
- Zhao, Senlin, et al.
(författare)
-
miR-4775 promotes colorectal cancer invasion and metastasis via the Smad7/TGF beta-mediated epithelial to mesenchymal transition
- 2017
-
Ingår i: Molecular Cancer. - : BIOMED CENTRAL LTD. - 1476-4598. ; 16
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Despite advancements in the diagnosis and treatment of colorectal cancer (CRC), many patients die because of tumor metastasis or recurrence. Therefore, identifying new prognostic markers and elucidating the mechanisms of CRC metastasis and recurrence will help to improve the prognosis of the disease. As dysregulation of microRNAs is strongly related to cancer progression, the aim of this study was to identify the role of miR-4775 in the prognosis of CRC patients and the underling mechanisms involved in CRC progression. Methods: qPCR and in situ hybridization were used to evaluate the expression of miR-4775 in 544 pairs of paraffin-embedded normal and CRC tissues. Kaplan-Meier analysis with the log-rank test was used for survival analyses. Immunohistochemical staining was applied to investigate the expression of miR-4775-regulated Smad7/TGF beta pathway-associated markers. In vitro and in vivo invasion and metastasis assays were used to explore the function of miR-4775 in the progression of CRC. Results: miR-4775 was identified as a high-risk factor for CRC metastasis and recurrence, with high levels predicting poor survival among the 544 studied CRC patients. Furthermore, high miR-4775 expression promoted the invasion of CRC cells as well as metastasis and the epithelial to mesenchymal transition (EMT) via Smad7-mediated activation of TGF beta signaling both in vitro and in vivo. Downregulating miR-4775 or overexpressing Smad7 reversed the tumor-promoting roles of miR-4775/ Smad7/TGF beta in vitro and in vivo. Conclusion: miR-4775 promotes CRC metastasis and recurrence in a Smad7/TGF beta signaling-dependent manner, providing a new therapeutic target for inhibiting the metastasis or recurrence of the disease.
|
|
