236 research outputs found
Microtube's Tapers Affect its Subwavelength Focusing Effect
AbstractA tapered microtube fabricated from a glass capillary tube can achieve subwavelength focusing at optical frequencies. This focusing effect is influenced by many factures. The role of taper ratios is invested in this paper with theoretical analysis and numerical simulation. It revealed that when the taper ratio is larger, the focusing spot has higher intensity and smaller FWHM
STAGE: Span Tagging and Greedy Inference Scheme for Aspect Sentiment Triplet Extraction
Aspect Sentiment Triplet Extraction (ASTE) has become an emerging task in
sentiment analysis research, aiming to extract triplets of the aspect term, its
corresponding opinion term, and its associated sentiment polarity from a given
sentence. Recently, many neural networks based models with different tagging
schemes have been proposed, but almost all of them have their limitations:
heavily relying on 1) prior assumption that each word is only associated with a
single role (e.g., aspect term, or opinion term, etc. ) and 2) word-level
interactions and treating each opinion/aspect as a set of independent words.
Hence, they perform poorly on the complex ASTE task, such as a word associated
with multiple roles or an aspect/opinion term with multiple words. Hence, we
propose a novel approach, Span TAgging and Greedy infErence (STAGE), to extract
sentiment triplets in span-level, where each span may consist of multiple words
and play different roles simultaneously. To this end, this paper formulates the
ASTE task as a multi-class span classification problem. Specifically, STAGE
generates more accurate aspect sentiment triplet extractions via exploring
span-level information and constraints, which consists of two components,
namely, span tagging scheme and greedy inference strategy. The former tag all
possible candidate spans based on a newly-defined tagging set. The latter
retrieves the aspect/opinion term with the maximum length from the candidate
sentiment snippet to output sentiment triplets. Furthermore, we propose a
simple but effective model based on the STAGE, which outperforms the
state-of-the-arts by a large margin on four widely-used datasets. Moreover, our
STAGE can be easily generalized to other pair/triplet extraction tasks, which
also demonstrates the superiority of the proposed scheme STAGE.Comment: Accepted by AAAI 202
Expanding CRISPR/Cas9 Genome Editing Capacity in Zebrafish Using SaCas9.
The type II CRISPR/Cas9 system has been used widely for genome editing in zebrafish. However, the requirement for the 5'-NGG-3' protospacer-adjacent motif (PAM) of Cas9 from Streptococcus pyogenes (SpCas9) limits its targeting sequences. Here, we report that a Cas9 ortholog from Staphylococcus aureus (SaCas9), and its KKH variant, successfully induced targeted mutagenesis with high frequency in zebrafish. Confirming previous findings, the SpCas9 variant, VQR, can also induce targeted mutations in zebrafish. Bioinformatics analysis of these new Cas targets suggests that the number of available target sites in the zebrafish genome can be greatly expanded. Collectively, the expanded target repertoire of Cas9 in zebrafish should further facilitate the utility of this organism for genetic studies of vertebrate biology
Number 2 Feibi Recipe Reduces PM2.5-Induced Lung Injury in Rats
Air pollution is the main cause of respiratory diseases. Fine particulates with the diameter below 2.5 μm can get into the alveoli and then enter the blood circulation through the lung tissue ventilation function and cause multiple systemic diseases especially the respiratory diseases. This study investigated the pathological mechanism of the lungs injury in rats induced by PM2.5 and the effect and mechanism of the Chinese herbal medicine number 2 Feibi Recipe (number 2 FBR) on lungs injury. In this experiment, Wistar rats were used. Lungs injury was induced by PM2.5. Number 2 FBR was used to treat the rats. The result showed that number 2 FBR could improve the lung injury in the rats. Meanwhile, it significantly reduced pathological response and inflammatory mediators including interleukin-6 (IL-6), interleukin-13 (IL-13), interleukin-17 (IL17), monocyte chemotactic protein-1 (MCP-1), and transforming growth factor-α (TNF-α) and upregulated glutathione peroxidase (GSH-Px) in the PM2.5 induced lung injury in the rats. Collectively, number 2 FBR appears to attenuate the lungs injury in rats induced by PM2.5
Identification and parameter determination of F-type Herbig stars from LAMOST DR8
We identify 20 F-type Herbig stars and provide a list of 22 pre-main-sequence
candidates from LAMOST DR8. The effective temperature, distance, extinction,
stellar luminosity, mass, and radius are derived for each Herbig star based on
optical spectra, photometry, Gaia EDR3 parallaxes, and pre-main-sequence
evolutionary tracks. According to spectral energy distributions, 19 F-type
Herbig stars belong to Class II YSOs, and one belongs to the flat-spectrum
class. Four have Spitzer IRS spectra, of which three show extremely weak
polycyclic aromatic hydrocarbons emissions, and three with both amorphous and
crystalline silicate emissions share the similar parameters and are at the same
evolutionary stage. We detect a solar-nearby outbursting EXor Herbig star
J034344.48+314309.3, possible precursor of a Herbig Ae star. Intense emission
lines of HI, HeI, OI, NaI, and CaII originated from the rapid accretion during
the outbursts are detected in its optical spectra, and silicate emission
features are detected in its infrared spectrum. We also make a statistic
analysis on the disk properties of all known Herbig stars using the defined
infrared spectral indices. The proportion of Herbig stars with moderate
infrared excesses decreases as effective temperature increases. The majority of
the precursors (F-, G-, or K- type) have moderate infrared excesses. Hotter
Herbig stars tend to have a larger proportion with large infrared excesses. The
trends may be due to the fact that hotter stars have larger areas of
re-emitting dust, although there is some scatter due to the particularities of
each disk.Comment: 23 pages, 9 Figures, ApJ accepte
Two-fold symmetric superconductivity in the kagome superconductor RbV3Sb5
The recent discovered kagome superconductors provide a good platform for
studying intertwined orders and novel states such as topology, superconductor,
charge density wave, et al. The interplay of these orders may spontaneously
break the rotational symmetry, and induce exotic phenomena such as nematicity,
or even nematic superconductor. Here we report a two-fold rotational symmetric
superconductivity of thin-film RbV3Sb5 in response to a direction-dependent
in-plane magnetic fields, in contrast to the six-fold structural symmetry of
the crystal lattice. The two-fold symmetry was evidenced by the
magnetoresistance transport experiments, critical magnetic field measurements
and the anisotropic superconducting gap. With different configuration, we
further observed the six-fold symmetry superimposed on the two-fold symmetry
near the boundary between normal states and superconducting states. Our results
present the correlation-driven symmetry breaking and highlight the promising
platform to study the intertwined orders such as unconventional
superconductivity in this correlated kagome family
Shenxiong Drop Pill exerts neuroprotective effect against focal cerebral ischemia partly via regulation of the expressions of ICAM-1 and caspase-3
Purpose: To investigate the effect of Shenxiong Drop Pill (SXDP) on cerebral infarction (CI) in rats, and the involvement of anti-inflammatory response in the process.Methods: Rats were sacrificed at three different time points, viz, 24, 48 and 72 h after establishment of CI model. Neurological deficit score (NDS) was determined using Bederson’s neurological behavioral scoring method, whereas triphenyltetrazolium chloride (TTC) staining was used to show brain injury. The integrated optical density (IOD) of Nissl bodies and caspase-3-positive nerve cells were measured with Nissl staining and SP kit, respectively. The mRNA expression of intercellular adhesion molecule 1(ICAM-1) was determined using reverse transcription-polymerase chain reaction (RT-PCR).Results: SXDP produced neuroprotective effect at high, medium, and low doses. The infarct volumes in the high-, medium- and low-dose SXDP, and cyclophosphamide groups were significantly reduced at each time point. Different doses of SXDP significantly reduced the mRNA expression of ICAM-1 and the IOD of caspase-3.Conclusion: These results indicate that SXDP exerts neuroprotective effects against ischemic injury by negatively regulating ICAM-1/caspase-3 downstream of inflammatory and apoptosis pathways
Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A campaign
The optical properties and chemical composition of PM1.0 particles in a suburban environment (Huairou) near the megacity of Beijing were measured during the HOPE-J3A (Haze Observation Project Especially for Jing–Jin–Ji Area) field campaign. The campaign covered the period November 2014 to January 2015 during the winter coal heating season. The average values and standard deviations of the extinction, scattering, absorption coefficients, and the aerosol single scattering albedo (SSA) at λ = 470 nm during the measurement period were 201 ± 240, 164 ± 202, 37 ± 43 Mm−1, and 0.80 ± 0.08, respectively. The average values for the real and imaginary components of the effective complex refractive index (CRI) over the campaign were 1.40 ± 0.06 and 0.03 ± 0.02, while the average mass scattering and absorption efficiencies (MSEs and MAEs) of PM1.0 were 3.6 and 0.7 m2 g−1, respectively. Highly time-resolved air pollution episodes clearly show the dramatic evolution of the PM1.0 size distribution, extensive optical properties (extinction, scattering, and absorption coefficients), and intensive optical properties (SSA and CRI) during haze formation, development, and decline. Time periods were classified into three different pollution levels (clear, slightly polluted, and polluted) for further analysis. It was found that (1) the relative contributions of organic and inorganic species to observed aerosol composition changed significantly from clear to polluted days: the organic mass fraction decreased from 50 to 43 % while the proportion of sulfates, nitrates, and ammonium increased strongly from 34 to 44 %. (2) Chemical apportionment of extinction, calculated using the IMPROVE algorithm, tended to underestimate the extinction compared to measurements. Agreement with measurements was improved by modifying the parameters to account for enhanced absorption by elemental carbon (EC). Organic mass was the largest contributor (52 %) to the total extinction of PM1.0, while EC, despite its low mass concentration of ∼ 4 %, contributed about 17 % to extinction. When the air quality deteriorated, the contribution of nitrate aerosol increased significantly (from 15 % on clear days to 22 % on polluted days). (3) Under polluted conditions, the average MAEs of EC were up to 4 times as large as the reference MAE value for freshly generated black carbon (BC). The temporal pattern of MAE values was similar to that of the OC / EC ratio, suggesting that non-BC absorption from secondary organic aerosol also contributes to particle absorption
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Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A campaign
The optical properties and chemical composition of PM1.0 particles in a suburban environment (Huairou) near the megacity of Beijing were measured during the HOPE-J3A (Haze Observation Project Especially for Jing–Jin–Ji Area) field campaign. The campaign covered the period November 2014 to January 2015 during the winter coal heating season. The average values and standard deviations of the extinction, scattering, absorption coefficients, and the aerosol single scattering albedo (SSA) at λ  =  470 nm during the measurement period were 201 ± 240, 164 ± 202, 37 ± 43 Mm−1, and 0.80 ± 0.08, respectively. The average values for the real and imaginary components of the effective complex refractive index (CRI) over the campaign were 1.40 ± 0.06 and 0.03 ± 0.02, while the average mass scattering and absorption efficiencies (MSEs and MAEs) of PM1.0 were 3.6 and 0.7 m2 g−1, respectively. Highly time-resolved air pollution episodes clearly show the dramatic evolution of the PM1.0 size distribution, extensive optical properties (extinction, scattering, and absorption coefficients), and intensive optical properties (SSA and CRI) during haze formation, development, and decline. Time periods were classified into three different pollution levels (clear, slightly polluted, and polluted) for further analysis. It was found that (1) the relative contributions of organic and inorganic species to observed aerosol composition changed significantly from clear to polluted days: the organic mass fraction decreased from 50 to 43 % while the proportion of sulfates, nitrates, and ammonium increased strongly from 34 to 44 %. (2) Chemical apportionment of extinction, calculated using the IMPROVE algorithm, tended to underestimate the extinction compared to measurements. Agreement with measurements was improved by modifying the parameters to account for enhanced absorption by elemental carbon (EC). Organic mass was the largest contributor (52 %) to the total extinction of PM1.0, while EC, despite its low mass concentration of  ∼  4 %, contributed about 17 % to extinction. When the air quality deteriorated, the contribution of nitrate aerosol increased significantly (from 15 % on clear days to 22 % on polluted days). (3) Under polluted conditions, the average MAEs of EC were up to 4 times as large as the reference MAE value for freshly generated black carbon (BC). The temporal pattern of MAE values was similar to that of the OC / EC ratio, suggesting that non-BC absorption from secondary organic aerosol also contributes to particle absorption
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