332 research outputs found
Facile fabrication of hierarchically porous carbonaceous monoliths with ordered mesostructure via an organic organic self-assembly
Ligustrazine Inhibits Growth, Migration and Invasion of Medulloblastoma Daoy Cells by Up-Regulation of miR-211
Background/Aims: Ligustrazine (LSZ) has been identified as an antitumor agent against some types of cancers. Nevertheless, its ability to inhibit growth, migration and invasion of medulloblastoma cells is still unclear. This study aimed to explore the effect of LSZ on Daoy cells. Methods: The effects of LSZ on viability, proliferation, apoptosis, migration, and invasion of Daoy cells were analyzed by CCK-8, BrdU, flow cytometry and Transwell assays, respectively. The effect of LSZ on miR-211 expression was analyzed by qRT-PCR. miR-211 inhibitor transfection was performed to suppress miR-211 expression. The effects of LSZ on apoptosis-related factors, MMP-2, MMP-9, and Vimentin (Vim), as well as main factors of PI3K/AKT and mTOR pathways were analyzed by Western blot. Results: LSZ inhibited viability but promoted apoptosis of Daoy cells. Additionally, the proliferative, migratory and invasive abilities of Daoy cells were decreased by LSZ. Meanwhile, LSZ promoted the activations of Caspase-3 and Caspase-9, increased Bax level, decreased Bcl-2 level, as well as inhibited the expressions of MMP-2, MMP-9 and Vim. Additionally, we found that LSZ enhanced miR-211 expression and exerted its anti-medulloblastoma effect by up-regulation of miR-211. Furthermore, LSZ inhibited PI3K/AKT and mTOR signaling pathways by up-regulating miR-211. Conclusion: LSZ suppressed medulloblastoma Daoy cells by up-regulating miR-211 and further modulating the activations of PI3K/AKT and mTOR signaling pathways
Broadening microwave absorption via a multi-domain structure
Materials with a high saturation magnetization have gained increasing attention in the field of microwave absorption; therefore, the magnetization value depends on the magnetic configuration inside them. However, the broad-band absorption in the range of microwave frequency (2-18 GHz) is a great challenge. Herein, the three-dimensional (3D) Fe/C hollow microspheres are constructed by iron nanocrystals permeating inside carbon matrix with a saturation magnetization of 340 emu/g, which is 1.55 times as that of bulk Fe, unexpectedly. Electron tomography, electron holography, and Lorentz transmission electron microscopy imaging provide the powerful testimony about Fe/C interpenetration and multi-domain state constructed by vortex and stripe domains. Benefiting from the unique chemical and magnetic microstructures, the microwave minimum absorption is as strong as -55 dB and the bandwidth (<-10 dB) spans 12.5 GHz ranging from 5.5 to 18 GHz. Morphology and distribution of magnetic nano-domains can be facilely regulated by a controllable reduction sintering under H2/Ar gas and an optimized temperature over 450-850 C. The findings might shed new light on the synthesis strategies of the materials with the broad-band frequency and understanding the association between multi-domain coupling and microwave absorption performance.This work was supported by the Ministry of Science and Technology of China (973 Project Nos. 2013CB932901 and 2016YFE0105700) and the National Natural Science Foundation of China (Nos. 51672050 and 51172047) and NSAF-U1330118. The authors extend their appreciation to the International Scientific Partnership Program ISPP at King Saud University for funding this research work through ISPP# 0018.Scopu
Grand Challenges in Chemistry for 2016 and Beyond
When several ACS Central Science Editors met
for dinner at the 2015 Pacifichem meeting,
conversation turned to the grand challenges
facing science and society, and those we felt chemistry was in a
unique position to solve. With the New Year, we thought we
would share our ideas in our first editorial of 2016. The arenas
in which we see chemistry having the largest influence are the
molecular bases of disease and aging, alternative energy
advancement, and the conservation of our elemental resources
Facile Synthesis of Uniform Virus-like Mesoporous Silica Nanoparticles for Enhanced Cellular Internalization
The low-efficiency cellular uptake property of current nanoparticles greatly restricts their application in the biomedical field. Herein, we demonstrate that novel virus-like mesoporous silica nanoparticles can easily be synthesized, showing greatly superior cellular uptake property. The unique virus-like mesoporous silica nanoparticles with a spiky tubular rough surface have been successfully synthesized via a novel single-micelle epitaxial growth approach in a low-concentration-surfactant oil/water biphase system. The virus-like nanoparticles' rough surface morphology results mainly from the mesoporous silica nanotubes spontaneously grown via an epitaxial growth process. The obtained nanoparticles show uniform particle size and excellent monodispersity. The structural parameters of the nanoparticles can be well tuned with controllable core diameter (60-160 nm), tubular length (6-70 nm), and outer diameter (6-10 nm). Thanks to the biomimetic morphology, the virus-like nanoparticles show greatly superior cellular uptake property (invading living cells in large quantities within few minutes, <5 min), unique internalization pathways, and extended blood circulation duration (t1/2 = 2.16 h), which is much longer than that of conventional mesoporous silica nanoparticles (0.45 h). Furthermore, our epitaxial growth strategy can be applied to fabricate various virus-like mesoporous core-shell structures, paving the way toward designed synthesis of virus-like nanocomposites for biomedicine applications. 2017 American Chemical Society.The work was supported by China National Key Basic Research Program (973 Project) (Nos. 2013CB934100 and 2012CB224805), NSFC (Grant Nos. 21322508 and 21210004), Shanghai Shuguang Program, China Postdoctoral Science Foundation (2015M570327). The authors extend their appreciation to the International Scientific Partnership Program ISPP at King Saud University for funding this research work through ISPP# 0018.Scopu
Radially oriented mesoporous TiO2 microspheres with single-crystal–like anatase walls for high-efficiency optoelectronic devices
Highly crystalline mesoporous materials with oriented configurations are in demand for high-performance energy conversion devices. We report a simple evaporation-driven oriented assembly method to synthesize three-dimensional open mesoporous TiO2 microspheres with a diameter of ~800 nm, well-controlled radially oriented hexagonal mesochannels, and crystalline anatase walls. The mesoporous TiO2 spheres have a large accessible surface area (112 m2/g), a large pore volume (0.164 cm3/g), and highly single-crystal–like anatase walls with dominant (101) exposed facets, making them ideal for conducting mesoscopic photoanode films. Dye-sensitized solar cells (DSSCs) based on the mesoporous TiO2 microspheres and commercial dye N719 have a photoelectric conversion efficiency of up to 12.1%. This evaporation-driven approach can create opportunities for tailoring the orientation of inorganic building blocks in the assembly of various mesoporous materials.State Key Basic Research Program of China (2013CB934104 and 2012CB224805), the National Science Foundation (21210004), the Science and Technology Commission of Shanghai Municipality (08DZ2270500), the Shanghai Leading Academic Discipline Project (B108), King Abdulaziz City for Science and Technology (project no. 29-280), and Deanship of Scientific Research, King Saud University–The International Highly Cited Research Group Program (IHCRG#14-102). Y.L. also acknowledges the Interdisciplinary Outstanding Doctoral Research Funding of Fudan University (EZH2203302/001)
The diploid genome sequence of an Asian individual
Here we present the first diploid genome sequence of an Asian individual. The genome was sequenced to 36-fold average coverage using massively parallel sequencing technology. We aligned the short reads onto the NCBI human reference genome to 99.97% coverage, and guided by the reference genome, we used uniquely mapped reads to assemble a high-quality consensus sequence for 92% of the Asian individual's genome. We identified approximately 3 million single-nucleotide polymorphisms (SNPs) inside this region, of which 13.6% were not in the dbSNP database. Genotyping analysis showed that SNP identification had high accuracy and consistency, indicating the high sequence quality of this assembly. We also carried out heterozygote phasing and haplotype prediction against HapMap CHB and JPT haplotypes (Chinese and Japanese, respectively), sequence comparison with the two available individual genomes (J. D. Watson and J. C. Venter), and structural variation identification. These variations were considered for their potential biological impact. Our sequence data and analyses demonstrate the potential usefulness of next-generation sequencing technologies for personal genomics
The Genomes of Oryza sativa: A History of Duplications
We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000–40,000. Only 2%–3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family
Facile fabrication of hierarchically porous carbonaceous monoliths with ordered mesostructure via an organic organic self-assembly
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