10 research outputs found
Energy coverage in wireless powered sub-6 GHz and millimeter wave dense cellular networks
This paper focuses on the energy coverage in wireless powered sub-6 GHz and millimeter wave (mmWave) dense cellular networks, where mobile devices harvest RF energy from sub-6 GHz or mmWave base stations (BSS). The expressions for energy coverage probability in sub-6 GHz and mmWave tiers are respectively derived. The comparisons between sub-6 GHz and mmWave RF energy harvesting are analyzed. In particular, we provide the sufficient conditions for the case that wireless energy harvesting in mmWave tier is better than that in sub-6 GHz tier. Furthermore, in hybrid cellular networks with mode selection mechanism, the probability that a mobile device selects a sub-6 GHz BS or mmWave BS for wireless power transfer is also theoretically obtained
Visualization 4: Camera array based light field microscopy
The applications of light field video of drosophila larva to 3D DPC and phase reconstruction. Originally published in Biomedical Optics Express on 01 September 2015 (boe-6-9-3179
Visualization 5: Camera array based light field microscopy
The light field and synthetic refocusing videos of the Caenorhabditis elegans (C. elegans) in the water. Originally published in Biomedical Optics Express on 01 September 2015 (boe-6-9-3179
Visualization 1: Camera array based light field microscopy
The proposed camera array based light field microscopy (CALM) prototype system. Originally published in Biomedical Optics Express on 01 September 2015 (boe-6-9-3179
Hybrid TiO<sub>2</sub>–SnO<sub>2</sub> Nanotube Arrays for Dye-Sensitized Solar Cells
Tin oxide (SnO<sub>2</sub>) is a promising wide band
gap semiconductor material for dye-sensitized solar cells (DSCs) because
of its high bulk electron mobility. Employing vertically ordered 1-D
nanostructures of SnO<sub>2</sub> as the photoanode may overcome the
limit of current DSCs by using new redox mediators with faster kinetics
than currently used ones. Synthesizing such nanostructures and integrating
them into DSCs, however, has been proven challenging. Here, we demonstrate
that, by using ZnO nanowires as a sacrificial template, vertically
aligned SnO<sub>2</sub> nanotube arrays may be feasibly synthesized
through a liquid-phase conversion process, and the synthesized SnO<sub>2</sub> nanotubes can be further coated with a thin layer of TiO<sub>2</sub> to form hybrid TiO<sub>2</sub>–SnO<sub>2</sub> nanotube
arrays. Both the resulting SnO<sub>2</sub> and hybrid TiO<sub>2</sub>–SnO<sub>2</sub> nanotube arrays are used to fabricate DSCs,
and the best performing cell delivers a promising efficiency of 3.53%.
Transient photovoltage measurements indicate that the electron recombination
lifetime in hybrid TiO<sub>2</sub>–SnO<sub>2</sub> nanotubes
is significantly larger than those in TiO<sub>2</sub> nanotubes, ZnO
nanowires, and films of sintered TiO<sub>2</sub> nanoparticles, suggesting
promise of the TiO<sub>2</sub>-coated SnO<sub>2</sub> nanotubes for
further improvement of DSCs
High-Efficiency Solid-State Dye-Sensitized Solar Cells Based on TiO<sub>2</sub>-Coated ZnO Nanowire Arrays
Replacing the liquid electrolytes in dye-sensitized solar
cells
(DSCs) with solid-state hole-transporting materials (HTMs) may solve
the packaging challenge and improve the long-term stability of DSCs.
The efficiencies of such solid-state DSCs (ss-DSCs), however, have
been far below the efficiencies of their counterparts that use liquid
electrolytes, primarily due to the challenges in filling HTMs into
thick enough sensitized films based on sintered TiO<sub>2</sub> nanoparticles.
Here we report fabrication of high-efficiency ss-DSCs using multilayer
TiO<sub>2</sub>-coated ZnO nanowire arrays as the photoanodes. The
straight channel between the vertically aligned nanostructures combined
with a newly developed multistep HTM filling process allows us to
effectively fill sensitized films as thick as 50 ÎĽm with the
HTMs. The resulting ss-DSCs yield an average power conversion efficiency
of 5.65%
Sorting Short Fragments of Single-Stranded DNA with an Evolving Electric Double Layer
We demonstrate a new procedure for separation of single-stranded
DNA (ssDNA) fragments that are anchored to the surface of a gold electrode
by end hybridization. The new separation procedure takes advantage
of the strong yet evolving nonuniform electric field near the gold
surface in contact with a buffer solution gradually being diluted
with deionized water. Separation of short ssDNA fragments is demonstrated
by monitoring the DNA at the gold surface with <i>in situ</i> fluorescence measurement. The experimental results can be rationalized
with a simple theoretical model of electric double layer that relates
the strength of the surface pulling force to the ionic concentration
of the changing buffer solution
Media 1: Coded aperture pair for quantitative phase imaging
Originally published in Optics Letters on 01 October 2014 (ol-39-19-5776
Media 2: Coded aperture pair for quantitative phase imaging
Originally published in Optics Letters on 01 October 2014 (ol-39-19-5776
A Glutamine-Rich Carrier Efficiently Delivers Anti-CD47 siRNA Driven by a “Glutamine Trap” To Inhibit Lung Cancer Cell Growth
It is not efficient enough using
the current approaches for tumor-selective
drug delivery based on the EPR effect and ligand–receptor interactions,
and they have largely failed to translate into the clinic. Therefore,
it is urgent to explore an enhanced strategy for effective delivery
of anticancer agents. Clinically, many cancers require large amounts
of glutamine for their continued growth and survival, resulting in
circulating glutamine extraction by the tumor being much greater than
that for any organs, behaving as a “glutamine trap”.
In the present study, we sought to elucidate whether the glutamine-trap
effect could be exploited to deliver therapeutic agents to selectively
kill cancer cells. Here, a macromolecular glutamine analogue, glutamine-functionalized
branched polyethylenimine (GPI), was constructed as the carrier to
deliver anti-CD47 siRNA for the blockage of CD47 “don’t
eat me” signals on cancer cells. The GPI/siRNA glutamine-rich
polyplexes exhibited remarkably high levels of cellular uptake by
glutamine-dependent lung cancer cells, wild-type A549 cells (A549<sup>WT</sup>), and its cisplatin-resistant cells (A549<sup>DDP</sup>),
specifically under glutamine-depleted conditions. It was noted that
the glutamine transporter ASCT2 was highly expressed both on A549<sup>WT</sup> and A549<sup>DDP</sup> but with almost no expression in
normal human lung fibroblasts cells. Inhibition of ASCT2 significantly
prevented the internalization of GPI polyplexes. These findings raised
the intriguing possibility that the glutamine-rich GPI polyplexes
utilize the ASCT2 pathway to selectively facilitate their cellular
uptake by cancer cells. GPI further delivered anti-CD47 siRNA efficiently
both in vitro and in vivo to downregulate the intratumoral mRNA and
protein expression levels of CD47. CD47 functions as a “don’t
eat me” signal and binds to the immunoreceptor SIRPα
inducing evasion of phagocytic clearance. GPI/anti-CD47 siRNA polyplexes
achieved significant antitumor activities both on A549<sup>WT</sup> and A549<sup>DDP</sup> tumor-bearing nude mice. Notably, it had
no adverse effect on CD47-expressing red blood cells and platelets,
likely because of selective delivery. Therefore, the glutamine-rich
carrier GPI driven by the glutamine-trap effect provides a promising
new strategy for designing anticancer drug delivery systems