188 research outputs found
MicroRNA-33b inhibits liver cancer cell proliferation, migration and invasion via down-regulation of Fli-1 and MMP-2 protein expressions
Purpose: To study the influence of microRNA-33b (miR-33b) on liver cancer cell proliferation, migration and invasiveness, and the mechanism involved. Methods: MicroRNA-33b or Fli-1 overexpression plasmid was transfected into liver cancer (SMMC7721) cells. Cell proliferation, migration, and invasiveness were determined using cell counting kit 8 (CCK-8), scratch test, and Transwell invasion assay, respectively. The amounts of miR-33b and Fli-1 in liver cancer tissues, paracancerous normal tissues, and miR-33b overexpression and control groups were measured using qRT-PCR, while protein concentration of matrix metalloproteinase 2 (MMP-2) was assayed using Western blotting. Results: Fli-1 protein was markedly upregulated in liver cancerous cells, relative to paracancerous normal tissues (p < 0.05). MicroRNA-33b protein expression was also significantly upregulated in miR33b overexpression group, but the corresponding Fli-1 expression was downregulated in miR-33b overexpression group, relative to control (p < 0.05). MicroRNA-33b overexpression significantly and time-dependently inhibited SMMC7721 cell proliferation and migration, but it reduced the degree of apoptosis (p < 0.05). Liver cancer (SMMC7721) cells in miR-33b overexpression group were less invasive than the control group (p < 0.05). Similarly, miR-33b overexpression significantly downregulated MMP-2 protein expression in SMMC7721cells (p < 0.05). Conclusion: Overexpression of miR-33b suppresses the proliferation, migratory and invasive potential of hepatic cancer cells via down-regulation of Fli-1 and MMP-2 protein expression. This finding may be useful in the identification of new liver cancer drugs
Hydrodeoxygenation of p-cresol on unsupported Ni–P catalysts prepared by thermal decomposition method
AbstractUnsupported Ni–P catalysts were prepared from the mixed precursor of NiCl2 and NaH2PO2 by thermal decomposition method, and their catalytic activities were measured using the hydrodeoxygenation (HDO) of p-cresol as probe. The effects of the H2PO2−/Ni2+ molar ratio in the precursor and the thermal decomposition temperature on the catalyst purity, crystallite size and HDO activity were studied. The HDO of p-cresol on these Ni–P catalysts proceeded with two parallel pathways yielding methylbenzene and methylcyclohexane as final products. The higher HDO catalytic activity of the catalyst was attributed to its bigger crystallite size and purer phase of Ni2P
Stencil Computation with Vector Outer Product
Matrix computation units have been equipped in current architectures to
accelerate AI and high performance computing applications. The matrix
multiplication and vector outer product are two basic instruction types. The
latter one is lighter since the inputs are vectors. Thus it provides more
opportunities to develop flexible algorithms for problems other than dense
linear algebra computing and more possibilities to optimize the implementation.
Stencil computations represent a common class of nested loops in scientific and
engineering applications. This paper proposes a novel stencil algorithm using
vector outer products. Unlike previous work, the new algorithm arises from the
stencil definition in the scatter mode and is initially expressed with formulas
of vector outer products. The implementation incorporates a set of
optimizations to improve the memory reference pattern, execution pipeline and
data reuse by considering various algorithmic options and the data sharing
between input vectors. Evaluation on a simulator shows that our design achieves
a substantial speedup compared with vectorized stencil algorithm
Plant trait-based life strategies of overlapping species vary in different succession stages of subtropical forests, Eastern China
Plants growing in forests at different succession stages in diverse habitats may adopt various life strategies from the perspective of plant functional traits. However, species composition differs with forest succession, and the effects of forest succession on traits have often been explored without considering the effects of species identity. We comprehensively investigated intraspecific variations in 12 traits of six overlapping species (two tree species and four understory shrub species) in three typical subtropical evergreen broad-leaved forests at different succession stages in eastern China. We found that intraspecific variations differed among traits. Fine root specific length presented large intraspecific variation, leaf area, specific leaf area and fine root tissue density showed medium intraspecific variations, and other traits displayed small intraspecific variations. Trees and understory shrubs in the early-stage forest exhibited higher leaf thickness, dry matter contents and tissue densities of leaves, roots, twigs, and stems and lower leaf area and specific leaf area. Those in the medium- and late-stage forests displayed contrasting trait characteristics. From the perspective of plant functional traits, plants in the early-stage forest formed a series of trait combinations for a resource conservative strategy with a low growth rate to adapt to fragile habitats with poor soil nutrients and changeable soil temperature and humidity, and those in the medium- and late-stage forests (especially the former) formed converse trait combinations for a resource acquisitive strategy with a high growth rate to adapt to low light availability and strongly competitive habitats. Our study reveals that plants in forests at different succession stages adopt various life strategies and provides data to the TRY and China plant trait databases
Amplification of light pulses with orbital angular momentum (OAM) in nitrogen ions lasing
Nitrogen ions pumped by intense femtosecond laser pulses give rise to optical
amplification in the ultraviolet range. Here, we demonstrated that a seed light
pulse carrying orbital angular momentum (OAM) can be significantly amplified in
nitrogen plasma excited by a Gaussian femtosecond laser pulse. With the
topological charge of +1 and -1, we observed an energy amplification of the
seed light pulse by two orders of magnitude, while the amplified pulse carries
the same OAM as the incident seed pulse. Moreover, we show that a spatial
misalignment of the plasma amplifier with the OAM seed beam leads to an
amplified emission of Gaussian mode without OAM, due to the special spatial
profile of the OAM seed pulse that presents a donut-shaped intensity
distribution. Utilizing this misalignment, we can implement an optical switch
that toggles the output signal between Gaussian mode and OAM mode. This work
not only certifies the phase transfer from the seed light to the amplified
signal, but also highlights the important role of spatial overlap of the
donut-shaped seed beam with the gain region of the nitrogen plasma for the
achievement of OAM beam amplification.Comment: 10 pages, 7 figure
Structured air lasing of N2+
Structured light has attracted great interest in scientific and technical
fields. Here, we demonstrate the first generation of structured air lasing in
N2+ driven by 800 nm femtosecond laser pulses. By focusing a vortex pump beam
at 800 nm in N2 gas, we generate a vortex superfluorescent radiation of N2+ at
391 nm, which carries the same photon orbital angular momentum as the pump
beam. With the injection of a Gaussian seed beam at 391 nm, the coherent
radiation is amplified, but the vorticity is unchanged. A new physical
mechanism is revealed in the vortex N2+ superfluorescent radiation: the vortex
pump beam transfers the spatial spiral phase into the N2+ gain medium, and the
Gaussian seed beam picks up the spatial spiral phase and is then amplified into
a vortex beam. Moreover, when we employ a pump beam with a cylindrical vector
mode, the Gaussian seed beam is correspondingly amplified into a cylindrical
vector beam. Surprisingly, the spatial polarization state of the amplified
radiation is identical to that of the vector pump beam regardless of whether
the Gaussian seed beam is linearly, elliptically, or circularly polarized.
Solving three-dimensional coupled wave equations, we show how a Gaussian beam
becomes a cylindrical vector beam in a cylindrically symmetric gain medium.
This study provides a novel approach to generating structured light via N2+ air
lasing.Comment: 18 pages, 5 figures, 3 equation
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