Shape-selective formation of monodisperse copper nanospheres and nanocubes via disproportionation reaction route and their optical properties

Synthesis of stable and monodisperse Cu nanocrystals of controlled morphology has been a long-standing challenge. In this Article, we report a facile disproportionation reaction approach for the synthesis of such nanocrystals in organic solvents. Either spherical or cubic shapes can be produced, depending on conditions. The typical Cu nanospheres are single crystals with a size of 23.4 ± 1.5 nm, and can self-assemble into three-dimensional (3D) nanocrystal superlattices with a large scale. By manipulating the chemical additives, monodisperse Cu nanocubes with tailorable sizes have also been obtained. The probable formation mechanism of these Cu nanocrystals is discussed. The narrow size distribution results in strong surface plasmon resonance (SPR) peaks even though the resonance is located in the interband transition region. Double SPR peaks are observed in the extinction spectra for the Cu nanocubes with relative large sizes. Theoretical simulation of the extinction spectra indicates that the SPR band located at longer wavelengths is caused by assembly of Cu nanocubes into more complex structures. The synthesis procedure that we report here is expected to foster systematic investigations on the physical properties and self-assembly of Cu nanocrystals with shape and size singularity for their potential applications in photonic and nanoelectronic devices. © 2014 American Chemical Society

DAPK1 as an independent prognostic marker in liver cancer

The death-associated protein kinase 1 (DAPK1) can act as an oncogene or a tumor suppressor gene depending on the cellular context as well as external stimuli. Our study aims to investigate the prognostic significance of DAPK1 in liver cancer in both mRNA and protein levels. The mRNA expression of DAPK1 was extracted from the Gene Expression Omnibus database in three independent liver cancer datasets while protein expression of DAPK1 was detected by immunohistochemistry in our Chinese liver cancer patient cohort. The associations between DAPK1 expression and clinical characteristics were tested. DAPK1 mRNA expression was down-regulated in liver cancer. Low levels of DAPK1 mRNA were associated with shorter survival in a liver cancer patient cohort (n = 115; p = 0.041), while negative staining of DAPK1 protein was significantly correlated with shorter time to progression (p = 0.002) and overall survival (p = 0.02). DAPK1 was an independent prognostic marker for both time to progression and overall survival by multivariate analysis. Liver cancer with the b-catenin mutation has a lower DAPK1 expression, suggesting that DAPK1 may be regulated under the b-catenin pathway. In addition, we also identified genes that are co-regulated with DAPK1. DAPK1 expression was positively correlated with IRF2, IL7R, PCOLCE and ZBTB16, and negatively correlated with SLC16A3 in both liver cancer datasets. Among these genes, PCOLCE and ZBTB16 were significantly down-regulated, while SLC16A3 was significantly upregulated in liver cancer. By using connectivity mapping of these co-regulated genes, we have identified amcinonide and sulpiride as potential small molecules that could potentially reverse DAPK1/PCOLCE/ZBTB16/SLC16A3 expression. Our study demonstrated for the first time that both DAPK1 mRNA and protein expression levels are important prognostic markers in liver cancer, and have identified genes that may contribute to DAPK1-mediated liver carcinogenesis

Disproportionation route to monodispersed copper nanoparticles for the catalytic synthesis of propargylamines

National Basic Research Program of China [2012CB933103]; National Outstanding Youth Science Foundation of China [50825101]; National Natural Science Foundation of China [51171157, 50971108]; Fundamental Research Funds for the Central Universities of China [201112G015]By taking advantage of the coordination between a monovalent Cu+ precursor and trioctylphosphine, monodisperse Cu nanoparticles were synthesized via a disproportionation reaction. A Cu@SiO2 nanocatalyst was formed by supporting Cu nanoparticles onto a silica aerogel, which showed a high surface area (779.53 m(2) g(-1)) and excellent catalytic activity for the synthesis of propargylamines

A facile approach to fabrication of well-dispersed NiO-ZnO composite hollow microspheres

A novel, facile and template-free approach was developed for the fabrication of amorphous zinc-nickel citrate hollow microspheres and crystalline well-dispersed NiO-ZnO composite hollow microspheres. In this approach, amorphous zinc-nickel citrate hollow microspheres were prepared through a simple chemical reaction and with room temperature ageing at nickel nitrate solution. The zinc-nickel citrate hollow microspheres have an average size of about 1.4 μm. The average thickness of the shell is about 300 nm. The content of Ni in the zinc-nickel citrate can be simply adjusted by changing the ageing time. The well-dispersed NiO-ZnO composite hollow microspheres can be prepared via the perfect morphology inheritance of the zinc-nickel citrate hollow microspheres, by calcination at 500 °C for 2 h. The optical absorption of the samples can extend into the visible region after the loading of NiO. The NiO-ZnO composite hollow microspheres with the high content of NiO exhibit the highest photocatalytic activity for the degradation of different organic dyes including Rhodamine-B, methylene blue and methyl orange under UV irradiation, which might be ascribed to their highest separation efficiency of photogenerated electron-hole pairs. In addition, these NiO-ZnO composite photocatalysts can be used repeatedly without a significant decrease of the photocatalytic activity under UV irradiation. ? 2013 The Royal Society of Chemistry

Photonics-based real-time ultra-high-range-resolution radar with broadband signal generation and processing

Abstract Real-time and high-resolution target detection is highly desirable in modern radar applications. Electronic techniques have encountered grave difficulties in the development of such radars, which strictly rely on a large instantaneous bandwidth. In this article, a photonics-based real-time high-range-resolution radar is proposed with optical generation and processing of broadband linear frequency modulation (LFM) signals. A broadband LFM signal is generated in the transmitter by photonic frequency quadrupling, and the received echo is de-chirped to a low frequency signal by photonic frequency mixing. The system can operate at a high frequency and a large bandwidth while enabling real-time processing by low-speed analog-to-digital conversion and digital signal processing. A conceptual radar is established. Real-time processing of an 8-GHz LFM signal is achieved with a sampling rate of 500 MSa/s. Accurate distance measurement is implemented with a maximum error of 4 mm within a range of ~3.5 meters. Detection of two targets is demonstrated with a range-resolution as high as 1.875 cm. We believe the proposed radar architecture is a reliable solution to overcome the limitations of current radar on operation bandwidth and processing speed, and it is hopefully to be used in future radars for real-time and high-resolution target detection and imaging

The Roles of microRNAs in Regulating the Expression of PD-1/PD-L1 Immune Checkpoint

Engagement of programmed death-ligand 1 (PD-L1) with its receptor programmed death 1 (PD-1) on T cells has been speculated to play a major role in suppressing the immune system, which helps tumor cells evade anti-tumor immunity. With the development of whole genome sequencing technologies, microRNAs have gained more attention as an important new layer of molecular regulation. Recent studies have revealed that altered expression of microRNAs play a pivotal role in immune checkpoint and various cellular processes in cancer. In this review, we focused on the latest progress about microRNAs research which involves the regulation of PD-1/PD-L1 immune checkpoint

Circular RNAs hsa-circ0000175 and hsa-circ0044235 in plasma are novel biomarkers for new-onset rheumatoid arthritis

Circular RNAs (circRNAs) are a class of non-coding RNAs that could serve as potential molecular markers for disease diagnosis. However, the role of circRNAs in plasma from new-onset rheumatoid arthritis (RA) has not been extensively investigated. In this study, the expression of hsa-circ0000175 and hsa-circ0044235 in plasma from RA patients, healthy controls (HCs), systemic lupus erythematosus (SLE) patients, osteoarthritis (OA), and undiagnosed arthritis (UA) patients were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Correlation analysis was used to assess the correlation of the two circRNAs and clinical variables of RA. The receiver operating characteristic (ROC) curves were created to evaluate the diagnostic value and multivariate analysis (logistic regression) was performed to analyse the risk factors. We confirmed that hsa-circ0000175 was significantly elevated in plasma from patients with new-onset RA compared with HC and patients with new-onset SLE, but significantly was reduced when compared with OA + UA patients. Hsa-circ0044235 was found to be significantly decreased in plasma from patients with new-onset RA compared with HC and OA + UA patients, but was significantly increased compared with SLE patients. The expression of plasma hsa-circ0000175 in new-onset RA patients was associated with platelet count (PLT), plateletcrit (PCT), and platelet large cell ratio (PLR), the expression of plasma hsa-circ0044235 new-onset RA patients was associated with swollen joint count (SJC), painful joint count (PJC), and disease activity score 28 (DAS28). ROC curve analysis suggested that the combination of hsa-circ0000175 and hsa-circ0044235 has some value in the diagnosis of new-onset RA from HC, patients with SLE and patients with OA + UA. The logistic regression analysis revealed that the expression of hsa-circ0000175 and hsa-circ0044235 in plasma were risk factors for RA. This study suggests that the combination of plasma hsa-circ0000175 and hsa-circ0044235 improves the diagnostic accuracy for new-onset RA. Moreover, the expression levels of plasma hsa-circ0000175 and hsa-circ0044235 were associated with disease activity and severity of RA

Template-free synthesis of amorphous double-shelled zinc-cobalt citrate hollow microspheres and their transformation to crystalline ZnCo 2O4 microspheres

A novel and facile approach was developed for the fabrication of amorphous double-shelled zinc-cobalt citrate hollow microspheres and crystalline double-shelled ZnCo2O4 hollow microspheres. In this approach, amorphous double-shelled zinc-cobalt citrate hollow microspheres were prepared through a simple route and with an aging process at 70 C. The combining inward and outward Ostwald ripening processes are adopted to account for the formation of these double-shelled architectures. The double-shelled ZnCo 2O4 hollow microspheres can be prepared via the perfect morphology inheritance of the double-shelled zinc-cobalt citrate hollow microspheres, by calcination at 500 C for 2 h. The resultant double-shelled ZnCo2O4 hollow microspheres manifest a large reversible capacity, superior cycling stability, and good rate capability. ? 2013 American Chemical Society

Magnetically separable and recyclable urchin-like Co-P hollow nanocomposites for catalytic hydrogen generation

One-pot well-controlled synthetic strategy was developed to achieve urchin-like Co-P hollow nanocomposites with tailorable magnetic properties which enable them to perform as magnetically recyclable nanocatalysts in a "quasi-homogeneous" system for the catalytic hydrogen generation via hydrolysis of Ammonia-Borane (AB). The key point of this strategy was that ferromagnetic Co nanoparticles (NPs) were embedded into paramagnetic Co 2P matrix to form magnetic nanocomposites. The as-prepared Co-P NPs showed appreciable catalytic activity, recyclability and durability in hydrolysis of AB. Moreover, the chemical regeneration of AB from the "hydrolyzate" may also benefit from these magnetically recyclable catalysts. We further highlighted the excellent high-temperature resistance of Co-P NPs by calcining them at 300 °C and 600°C. Our research may facilitate the practical application of AB as a sustainable hydrogen storage material for hydrogen-based energy. ? 2014 Elsevier B.V. All rights reserved