9 research outputs found
Metal-Organic-Framework-Derived N‑Doped Hierarchically Porous Carbon Polyhedrons Anchored on Crumpled Graphene Balls as Efficient Selenium Hosts for High-Performance Lithium–Selenium Batteries
Developing carbon
scaffolds showing rational pore structures as
cathode hosts is essential for achieving superior electrochemical
performances of lithium–selenium (Li–Se) batteries.
Hierarchically porous N-doped carbon polyhedrons anchored on crumpled
graphene balls (NPC/CGBs) are synthesized by carbonizing a zeolitic
imidazolate framework-8 (ZIF-8)/CGB composite precursor, producing
an unprecedented effective host matrix for high-performance Li–Se
batteries. Mesoporous CGBs obtained by one-pot spray pyrolysis are
used as a highly conductive matrix for uniform polyhedral ZIF-8 growth.
During carbonization, ZIF-8 polyhedrons on mesoporous CGBs are converted
into N-doped carbon polyhedrons showing abundant micropores, forming
a high-surface-area, high-pore-volume hierarchically porous NPC/CGB
composite whose small unique pores effectively confine Se during melt
diffusion, thereby providing conductive electron pathways. Thus, the
integrated NPC/CGB-Se composite ensures high Se utilization originating
from complete electrochemical reactions between Se and Li ions. The
NPC/CGB-Se composite cathode exhibits high discharge capacities (998
and 462 mA h g<sup>–1</sup> at the 1st and 1000th cycles, respectively,
at a 0.5 C current density), good capacity retention (68%, calculated
from the 3rd cycle), and excellent rate capability. A discharge capacity
of 409 mA h g<sup>–1</sup> is achieved even at an extremely
high (15.0 C) current density
Doubling Absorption in Nanowire Solar Cells with Dielectric Shell Optical Antennas
Semiconductor
nanowires (NWs) often exhibit efficient, broadband
light absorption despite their relatively small size. This characteristic
originates from the subwavelength dimensions and high refractive indices
of the NWs, which cause a light-trapping optical antenna effect. As
a result, NWs could enable high-efficiency but low-cost solar cells
using small volumes of expensive semiconductor material. Nevertheless,
the extent to which the antenna effect can be leveraged in devices
will largely determine the economic viability of NW-based solar cells.
Here, we demonstrate a simple, low-cost, and scalable route to dramatically
enhance the optical antenna effect in NW photovoltaic devices by coating
the wires with conformal dielectric shells. Scattering and absorption
measurements on Si NWs coated with shells of SiN<sub><i>x</i></sub> or SiO<sub><i>x</i></sub> exhibit a broadband enhancement
of light absorption by ∼50–200% and light scattering
by ∼200–1000%. The increased light–matter interaction
leads to a ∼80% increase in short-circuit current density in
Si photovoltaic devices under 1 sun illumination. Optical simulations
reproduce the experimental results and indicate the dielectric–shell
effect to be a general phenomenon for groups IV, II–VI, and
III–V semiconductor NWs in both lateral and vertical orientations,
providing a simple route to approximately double the efficiency of
NW-based solar cells
Switching of Photonic Crystal Lasers by Graphene
Unique features of graphene have
motivated the development of graphene-integrated photonic devices.
In particular, the electrical tunability of graphene loss enables
high-speed modulation of light and tuning of cavity resonances in
graphene-integrated waveguides and cavities. However, efficient control
of light emission such as lasing, using graphene, remains a challenge.
In this work, we demonstrate on/off switching of single- and double-cavity
photonic crystal lasers by electrical gating of a monolayer graphene
sheet on top of photonic crystal cavities. The optical loss of graphene
was controlled by varying the gate voltage <i>V</i><sub>g</sub>, with the ion gel atop the graphene sheet. First, the fundamental
properties of graphene were investigated through the transmittance
measurement and numerical simulations. Next, optically pumped lasing
was demonstrated for a graphene-integrated single photonic crystal
cavity at <i>V</i><sub>g</sub> below −0.6 V, exhibiting
a low lasing threshold of ∼480 μW, whereas lasing was
not observed at <i>V</i><sub>g</sub> above −0.6 V
owing to the intrinsic optical loss of graphene. Changing quality
factor of the graphene-integrated photonic crystal cavity enables
or disables the lasing operation. Moreover, in the double-cavity photonic
crystal lasers with graphene, switching of individual cavities with
separate graphene sheets was achieved, and these two lasing actions
were controlled independently despite the close distance of ∼2.2
μm between adjacent cavities. We believe that our simple and
practical approach for switching in graphene-integrated active photonic
devices will pave the way toward designing high-contrast and ultracompact
photonic integrated circuits
Data_Sheet_2_Long-term survival benefits of intrathecal autologous bone marrow-derived mesenchymal stem cells (Neuronata-R®: lenzumestrocel) treatment in ALS: Propensity-score-matched control, surveillance study.docx
ObjectiveNeuronata-R® (lenzumestrocel) is an autologous bone marrow-derived mesenchymal stem cell (BM-MSC) product, which was conditionally approved by the Korean Ministry of Food and Drug Safety (KMFDS, Republic of Korea) in 2013 for the treatment of amyotrophic lateral sclerosis (ALS). In the present study, we aimed to investigate the long-term survival benefits of treatment with intrathecal lenzumestrocel.MethodsA total of 157 participants who received lenzumestrocel and whose symptom duration was less than 2 years were included in the analysis (BM-MSC group). The survival data of placebo participants from the Pooled-Resource Open-Access ALS Clinical Trials (PROACT) database were used as the external control, and propensity score matching (PSM) was used to reduce confounding biases in baseline characteristics. Adverse events were recorded during the entire follow-up period after the first treatment.ResultsSurvival probability was significantly higher in the BM-MSC group compared to the external control group from the PROACT database (log-rank, p ConclusionThe results of the present study showed that lenzumestrocel treatment had a long-term survival benefit in real-world ALS patients.</p
Enhancement of Light Absorption in Silicon Nanowire Photovoltaic Devices with Dielectric and Metallic Grating Structures
We report the enhancement
of light absorption in Si nanowire photovoltaic
devices with one-dimensional dielectric or metallic gratings that
are fabricated by a damage-free, precisely aligning, polymer-assisted
transfer method. Incorporation of a Si<sub>3</sub>N<sub>4</sub> grating
with a Si nanowire effectively enhances the photocurrents for transverse-electric
polarized light. The wavelength at which a maximum photocurrent is
generated is readily tuned by adjusting the grating pitch. Moreover,
the electrical properties of the nanowire devices are preserved before
and after transferring the Si<sub>3</sub>N<sub>4</sub> gratings onto
Si nanowires, ensuring that the quality of pristine nanowires is not
degraded during the transfer. Furthermore, we demonstrate Si nanowire
photovoltaic devices with Ag gratings using the same transfer method.
Measurements on the fabricated devices reveal approximately 27.1%
enhancement in light absorption compared to that of the same devices
without the Ag gratings without any degradation of electrical properties.
We believe that our polymer-assisted transfer method is not limited
to the fabrication of grating-incorporated nanowire photovoltaic devices
but can also be generically applied for the implementation of complex
nanoscale structures toward the development of multifunctional optoelectronic
devices
Antibody profiles for MuSK, LRP4, and clustered AChR in patients with MG seronegative for AChR antibody on radioimmunoprecipitation assay.
<p>LEMS, Lambert-Eaton myasthenic syndrome; MND, motor neuron disease; MG, myasthenia gravis; MuSK, muscle-specific tyrosine kinase; CBA, cell-based assay; RIPA, radioimmunoprecipitation assay; LRP4, low-density lipoprotein receptor-related protein 4; cAChR, clustered acetylcholine receptor.</p
Clinical features of AChR antibody seronegative generalized MG (on radioimmunoprecipitation assay) according to the antibody profile.
<p>Clinical features of AChR antibody seronegative generalized MG (on radioimmunoprecipitation assay) according to the antibody profile.</p
Clinical features of the patients with the LRP4 antibody, and of the patients who were double seropositive.
<p>Clinical features of the patients with the LRP4 antibody, and of the patients who were double seropositive.</p
Cell based assays to detect antibodies to clustered AChR, MuSK or LRP4.
<p><b>Patient IgG binding is shown in red. For the AChR and MuSK assays, EGFP tags exhibit a green fluorescence highlighting the transfected cells; there is no color tag in the LRP4 assay. Patient 41 is positive for AChR, Patient 42 is positive for MuSK antibodies, and patient 72 is low positive for LRP4 antibodies.</b> MuSK, muscle-specific tyrosine kinase; LRP4, low-density lipoprotein receptor-related protein 4; AChR, acetylcholine receptor.</p