1,129 research outputs found
Mobility enhancement and highly efficient gating of monolayer MoS2 transistors with Polymer Electrolyte
We report electrical characterization of monolayer molybdenum disulfide
(MoS2) devices using a thin layer of polymer electrolyte consisting of
poly(ethylene oxide) (PEO) and lithium perchlorate (LiClO4) as both a
contact-barrier reducer and channel mobility booster. We find that bare MoS2
devices (without polymer electrolyte) fabricated on Si/SiO2 have low channel
mobility and large contact resistance, both of which severely limit the
field-effect mobility of the devices. A thin layer of PEO/ LiClO4 deposited on
top of the devices not only substantially reduces the contact resistance but
also boost the channel mobility, leading up to three-orders-of-magnitude
enhancement of the field-effect mobility of the device. When the polymer
electrolyte is used as a gate medium, the MoS2 field-effect transistors exhibit
excellent device characteristics such as a near ideal subthreshold swing and an
on/off ratio of 106 as a result of the strong gate-channel coupling.Comment: 17 pages, 4 figures, accepted by J. Phys.
Efficient multipartite entanglement purification with non-identical states
We present an efficient and general multipartite entanglement purification
protocol (MEPP) for N-photon systems in Greenberger-Horne-Zeilinger (GHZ)
states with non-identical input states. As a branch of entanglement
purification, besides the cases of successful purification, the recurrence MEPP
actually has the reusable discarded items which are usually regarded as a
failure. Our protocol contains two parts for bit-flip error correction. The
first one is the conventional MEPP, corresponding successful cases. The second
one includes two efficient approaches, recycling purification with entanglement
link and direct residual entanglement purification, that can utilize discarded
items. We also make a comparison between two approaches. Which method to use
depends on initial input states, and in most cases the approach of direct
residual purification is optimal for it not only may obtain a higher fidelity
entangled state but also it does not require additional sophisticated links. In
addition, for phase-flip errors, the discarded items still have available
residual entanglement in the case of different input states. With these
approaches, this MEPP has a higher efficiency than all previous MEPPs and it
may have potential applications in the future long-distance quantum
communications and networks.Comment: 20 pages,12 figure
Relation between quantum illumination and quantum parameter estimation
Quantum illumination (QI) leverages entangled lights to detect the potential
presence of low-reflective objects in a region surrounded by a thermal bath.
Homologously, quantum parameter estimation utilizes non-classical probes to
accurately estimate the value of the unknown parameter(s) of interest in a
system. There appears to be a certain connection between these two areas.
However, they are commonly studied using different figures of merit:
signal-to-noise ratio and quantum Fisher information. In this study, we prove
that the two measures are equivalent to QI in the limit of zero object
reflectivity. We further demonstrate this equivalence by investigating QI
protocols employing non-Gaussian states, which are obtained by de-Gaussifying
the two-mode squeezed vacuum state with photon addition and photon subtraction.
However, our analysis leads to a no-go result which demonstrates that
de-Gaussification operations do not offer an advantage compared to the null
case.Comment: 9 pages,3 figure
Centrality, system size and energy dependences of charged-particle pseudo-rapidity distribution
Utilizing the three-fireball picture within the quark combination model, we
study systematically the charged particle pseudorapidity distributions in both
Au+Au and Cu+Cu collision systems as a function of collision centrality and
energy, 19.6, 62.4, 130 and 200 GeV, in full pseudorapidity
range. We find that: (i)the contribution from leading particles to
distributions increases with the decrease of the collision
centrality and energy respectively; (ii)the number of the leading particles is
almost independent of the collision energy, but it does depend on the nucleon
participants ; (iii)if Cu+Cu and Au+Au collisions at the same
collision energy are selected to have the same , the resulting of
charged particle distributions are nearly identical, both in the
mid-rapidity particle density and the width of the distribution. This is true
for both 62.4 GeV and 200 GeV data. (iv)the limiting fragmentation phenomenon
is reproduced. (iiv) we predict the total multiplicity and pseudorapidity
distribution for the charged particles in Pb+Pb collisions at TeV. Finally, we give a qualitative analysis of the
and as function of
and from RHIC to LHC.Comment: 12 pages, 8 figure
Fractional Denoising for 3D Molecular Pre-training
Coordinate denoising is a promising 3D molecular pre-training method, which
has achieved remarkable performance in various downstream drug discovery tasks.
Theoretically, the objective is equivalent to learning the force field, which
is revealed helpful for downstream tasks. Nevertheless, there are two
challenges for coordinate denoising to learn an effective force field, i.e. low
coverage samples and isotropic force field. The underlying reason is that
molecular distributions assumed by existing denoising methods fail to capture
the anisotropic characteristic of molecules. To tackle these challenges, we
propose a novel hybrid noise strategy, including noises on both dihedral angel
and coordinate. However, denoising such hybrid noise in a traditional way is no
more equivalent to learning the force field. Through theoretical deductions, we
find that the problem is caused by the dependency of the input conformation for
covariance. To this end, we propose to decouple the two types of noise and
design a novel fractional denoising method (Frad), which only denoises the
latter coordinate part. In this way, Frad enjoys both the merits of sampling
more low-energy structures and the force field equivalence. Extensive
experiments show the effectiveness of Frad in molecular representation, with a
new state-of-the-art on 9 out of 12 tasks of QM9 and on 7 out of 8 targets of
MD17
Residue-specific structures and membrane locations of pH-low insertion peptide by solid-state nuclear magnetic resonance
The pH-low insertion peptide (pHLIP) binds to a membrane at pH 7.4 unstructured but folds across the bilayer as a transmembrane helix at pH similar to 6. Despite their promising applications as imaging probes and drug carriers that target cancer cells for cytoplasmic cargo delivery, the mechanism of pH modulation on pHLIP-membrane interactions has not been completely understood. Here, we show the first study on membrane-associated pHLIP using solid-state NMR spectroscopy. Data on residue-specific conformation and membrane location describe pHLIP in various surface-bound and membrane-inserted states at pH 7.4, 6.4 and 5.3. The critical membrane-adsorbed state is more complex than previously envisioned. At pH 6.4, for the major unstructured population, the peptide sinks deeper into the membrane in a state II\u27 that is distinct from the adsorbed state II observed at pH 7.4, which may enable pHLIP to sense slight change in acidity even before insertion
Using T-cell repertoire profiles as predictor in a primary mucosal melanoma
Dear Editor, Primary mucosal melanoma is a rare subtype of melanoma that carries poor prognosis. Traditional treatment options of mucosal melanoma are surgery, radiation, and chemotherapy; but the overall survival remains low.1 Cytotoxic T‐lymphocyte associated protein 4 (CLTA‐4) and programmed cell death protein 1 (PD‐1), both inhibitory immune checkpoints commonly seen on activated T cells, have been found to be promising targets for treatment of advanced cancers.2 However, the efficacy and response to immunotherapy in mucosal melanoma remains unknown. Herein, we report a case involving a patient, who was a 70‐year‐old male and referred to Taipei Medical University Hospital with confirmed diagnosis of mucosa melanoma over hard plate of mouth. The patient was admitted and subjected to anti‐PD‐1 immunotherapy (pembrolizumab 200 mg every 3 weeks) (Figure 1A). Serial imaging of primary malignant melanoma of the hard palate showed that the tumor size gradually decreased after treatment with pembrolizumab, suggesting partial response/stable disease secondary to continuous immunotherapy (Figure 1B). However, after seventh cycle of treatment, magnetic resonance imaging (MRI) revealed enlarged previous known metastatic lesions and new tumor nodules in brain (Figure 1B). The patient received stereotactic radiation therapy before treatment cycle 14 (Figure 1A). Although the primary metastatic brain lesions were smaller and stationary after radiotherapy, the following brain MRI displayed several hyperdensity masses in the right frontal lobe with perifocal edema and mild mass effect (Figure 1B). Subsequently, patient suffered from infection and respiratory distress and died 2 months after 17th cycle of pembrolizumab therapy
Using T-cell repertoire profiles as predictor in a primary mucosal melanoma
Dear Editor, Primary mucosal melanoma is a rare subtype of melanoma that carries poor prognosis. Traditional treatment options of mucosal melanoma are surgery, radiation, and chemotherapy; but the overall survival remains low.1 Cytotoxic T‐lymphocyte associated protein 4 (CLTA‐4) and programmed cell death protein 1 (PD‐1), both inhibitory immune checkpoints commonly seen on activated T cells, have been found to be promising targets for treatment of advanced cancers.2 However, the efficacy and response to immunotherapy in mucosal melanoma remains unknown. Herein, we report a case involving a patient, who was a 70‐year‐old male and referred to Taipei Medical University Hospital with confirmed diagnosis of mucosa melanoma over hard plate of mouth. The patient was admitted and subjected to anti‐PD‐1 immunotherapy (pembrolizumab 200 mg every 3 weeks) (Figure 1A). Serial imaging of primary malignant melanoma of the hard palate showed that the tumor size gradually decreased after treatment with pembrolizumab, suggesting partial response/stable disease secondary to continuous immunotherapy (Figure 1B). However, after seventh cycle of treatment, magnetic resonance imaging (MRI) revealed enlarged previous known metastatic lesions and new tumor nodules in brain (Figure 1B). The patient received stereotactic radiation therapy before treatment cycle 14 (Figure 1A). Although the primary metastatic brain lesions were smaller and stationary after radiotherapy, the following brain MRI displayed several hyperdensity masses in the right frontal lobe with perifocal edema and mild mass effect (Figure 1B). Subsequently, patient suffered from infection and respiratory distress and died 2 months after 17th cycle of pembrolizumab therapy
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