5,902 research outputs found
Starless Cloud Core L1517B in Envelope Expansion with Core Collapse
Various spectral emission lines from star-forming molecular cloud core L1517B
manifest red asymmetric double-peaked profiles with stronger red peaks and
weaker blue peaks, in contrast to the oft-observed blue-skewed molecular
spectral line profiles with blue peaks stronger than red peaks. Invoking a
spherically symmetric general polytropic hydrodynamic shock model for the
envelope expansion with core collapse (EECC) phase, we show the radial flow
velocity, mass density and temperature structures of self-similar evolution for
L1517B in a dynamically consistent manner. By prescribing simple radial
profiles of abundance distribution for pertinent molecules, we perform
molecular excitation and radiative transfer calculations using the publicly
available RATRAN code set for the spherically symmetric case. Our computational
results show that the EECC model reproduces molecular spectral line profiles in
sensible agreement with observational data of IRAM, FCRAO and Effelsberg 100 m
telescopes for L1517B. We also report spatially resolved observations of
optically thick line HCO+(1-0) using the Purple Mountain Observatory (PMO) 13.7
m telescope at Delingha in China and the relevant fitting results. Hyperfine
line structures of NH3 and N2H+ transitions are also fitted to consistently
reveal the dynamics of central core collapse. As a consistent model check,
radial profiles of 1.2 mm and 0.85 mm dust continua observed by IRAM 30 m
telescope and SCUBA, respectively, are also fitted numerically using the same
EECC model that produces the molecular line profiles. L1517B is likely
undergoing an EECC shock phase. For future observational tests, we also predict
several molecular line profiles with spatial distributions, radial profile of
sub-millimeter continuum at wavelength 0.45mm, as well as the radial profiles
of the column density and visual extinction for L1517B.Comment: 18 pages, 11 figures, accepted for publication in Ap
High-performance biosensing systems based on various nanomaterials as signal transducers
autho
Advances in Microfluidics and Lab-on-a-Chip Technologies
Advances in molecular biology are enabling rapid and efficient analyses for
effective intervention in domains such as biology research, infectious disease
management, food safety, and biodefense. The emergence of microfluidics and
nanotechnologies has enabled both new capabilities and instrument sizes
practical for point-of-care. It has also introduced new functionality, enhanced
sensitivity, and reduced the time and cost involved in conventional molecular
diagnostic techniques. This chapter reviews the application of microfluidics
for molecular diagnostics methods such as nucleic acid amplification,
next-generation sequencing, high resolution melting analysis, cytogenetics,
protein detection and analysis, and cell sorting. We also review microfluidic
sample preparation platforms applied to molecular diagnostics and targeted to
sample-in, answer-out capabilities
Direct evidence of ZnO morphology modification via the selective adsorption of ZnO-binding peptides
Biomolecule-mediated ZnO synthesis has great potential for the tailoring of ZnO morphology for specific application in biosensors, window materials for display and solar cells, dye-sensitized solar cells (DSSCs), biomedical materials, and photocatalysts due to its specificity and multi-functionality. In this contribution, the effect of a ZnO-binding peptide (ZnO-BP, G-12: GLHVMHKVAPPR) and its GGGC-tagged derivative (GT-16: GLHVMHKVAPPRGGGC) on the growth of ZnO crystals expressing morphologies dependent on the relative growth rates of (0001) and (10 (1) over bar0) planes of ZnO have been studied. The amount of peptide adsorbed was determined by a depletion method using oriented ZnO films grown by Atomic Layer Deposition (ALD), while the adsorption behavior of G-12 and GT-16 was investigated using XPS and a computational approach. Direct evidence was obtained to show that (i) both the ZnO-BP identified by phage display and its GGGC derivative (GT-16) are able to bind to ZnO and modify crystal growth in a molecule and concentration dependent fashion, (ii) plane selectivity for interaction with the (0001) versus the (10 (1) over bar0) crystal planes is greater for GT-16 than G-12; and (iii) specific peptide residues interact with the crystal surface albeit in the presence of charge compensating anions. To our knowledge, this is the first study to provide unambiguous and direct quantitative experimental evidence of the modification of ZnO morphology via (selective and nonselective) adsorption-growth inhibition mechanisms mediated by a ZnO-BP identified from phage display libraries
Longer telomere length in peripheral white blood cells is associated with risk of lung cancer and the rs2736100 (CLPTM1L-TERT) polymorphism in a prospective cohort study among women in China.
A recent genome-wide association study of lung cancer among never-smoking females in Asia demonstrated that the rs2736100 polymorphism in the TERT-CLPTM1L locus on chromosome 5p15.33 was strongly and significantly associated with risk of adenocarcinoma of the lung. The telomerase gene TERT is a reverse transcriptase that is critical for telomere replication and stabilization by controlling telomere length. We previously found that longer telomere length measured in peripheral white blood cell DNA was associated with increased risk of lung cancer in a prospective cohort study of smoking males in Finland. To follow up on this finding, we carried out a nested case-control study of 215 female lung cancer cases and 215 female controls, 94% of whom were never-smokers, in the prospective Shanghai Women's Health Study cohort. There was a dose-response relationship between tertiles of telomere length and risk of lung cancer (odds ratio (OR), 95% confidence interval [CI]: 1.0, 1.4 [0.8-2.5], and 2.2 [1.2-4.0], respectively; P trend = 0.003). Further, the association was unchanged by the length of time from blood collection to case diagnosis. In addition, the rs2736100 G allele, which we previously have shown to be associated with risk of lung cancer in this cohort, was significantly associated with longer telomere length in these same study subjects (P trend = 0.030). Our findings suggest that individuals with longer telomere length in peripheral white blood cells may have an increased risk of lung cancer, but require replication in additional prospective cohorts and populations
TNF-α Promotes Nuclear Enrichment of TonEBP/NFAT5 to Selectively Control Inflammatory but not Osmoregulatory Responses in Nucleus Pulposus Cells.
Intervertebral disc degeneration (IDD) causes chronic back pain and is linked to production of proinflammatory molecules by nucleus pulposus (NP) and other disc cells. Activation of TonicityResponsive Enhancer-Binding Protein (TonEBP)/NFAT5 by non-osmotic stimuli, including pro-inflammatory molecules, occurs in cells involved in immune response. However, whether inflammatory stimuli activate TonEBP in NP cells and if TonEBP controls inflammation during IDD is unknown. We show that TNF-α, but not IL-1β or LPS, promoted nuclear enrichment of TonEBP protein. However, TNF-α-mediated activation of TonEBP did not cause induction of osmo-regulatory genes. RNA-sequencing showed that 8.5% of TNF-α transcriptional responses were TonEBP-dependent and identified genes regulated by both TNF-α and TonEBP. These genes were over-enriched in pathways and diseases related to Inflammatory Response and Inhibition of Matrix Metalloproteases. Based on RNA-seq results, we further investigated regulation of novel TonEBP targets CXCL1, CXCL2, and CXCL3. TonEBP acted synergistically with TNF-α and LPS to induce CXCL1 proximal promoter activity. Interestingly, this regulation required a highly conserved NF-κB binding site but not a predicted TonE, suggesting crosstalk between these two members of the Rel family. Finally, analysis of human NP tissue showed that TonEBP expression correlated with canonical osmo-regulatory targets TauT/SLC6A6, SMIT/SLC5A3, and AR/AKR1B1, supporting in vitro findings that the inflammatory milieu during IDD does not interfere with TonEBP osmoregulation. In summary, while TonEBP participates in the pro-inflammatory response to TNF-α, therapeutic strategies targeting this transcription factor for treatment of disc disease must spare osmo-protective, pro-survival, and matrix homeostatic activities. [Abstract copyright: Copyright © 2017, The American Society for Biochemistry and Molecular Biology.
Leveraging phone-level linguistic-acoustic similarity for utterance-level pronunciation scoring
Recent studies on pronunciation scoring have explored the effect of
introducing phone embeddings as reference pronunciation, but mostly in an
implicit manner, i.e., addition or concatenation of reference phone embedding
and actual pronunciation of the target phone as the phone-level pronunciation
quality representation. In this paper, we propose to use linguistic-acoustic
similarity to explicitly measure the deviation of non-native production from
its native reference for pronunciation assessment. Specifically, the deviation
is first estimated by the cosine similarity between reference phone embedding
and corresponding acoustic embedding. Next, a phone-level Goodness of
pronunciation (GOP) pre-training stage is introduced to guide this
similarity-based learning for better initialization of the aforementioned two
embeddings. Finally, a transformer-based hierarchical pronunciation scorer is
used to map a sequence of phone embeddings, acoustic embeddings along with
their similarity measures to predict the final utterance-level score.
Experimental results on the non-native databases suggest that the proposed
system significantly outperforms the baselines, where the acoustic and phone
embeddings are simply added or concatenated. A further examination shows that
the phone embeddings learned in the proposed approach are able to capture
linguistic-acoustic attributes of native pronunciation as reference.Comment: Accepted by ICASSP 202
Partial wave analysis of J/psi to p pbar pi0
Using a sample of 58 million events collected with the BESII
detector at the BEPC, more than 100,000 events are
selected, and a detailed partial wave analysis is performed. The branching
fraction is determined to be . A long-sought `missing' , first observed in , is observed in this decay too, with mass and width of
MeV/c and MeV/c,
respectively. Its spin-parity favors . The masses, widths, and
spin-parities of other states are obtained as well.Comment: Add one author nam
An ASR-free Fluency Scoring Approach with Self-Supervised Learning
A typical fluency scoring system generally relies on an automatic speech
recognition (ASR) system to obtain time stamps in input speech for either the
subsequent calculation of fluency-related features or directly modeling speech
fluency with an end-to-end approach. This paper describes a novel ASR-free
approach for automatic fluency assessment using self-supervised learning (SSL).
Specifically, wav2vec2.0 is used to extract frame-level speech features,
followed by K-means clustering to assign a pseudo label (cluster index) to each
frame. A BLSTM-based model is trained to predict an utterance-level fluency
score from frame-level SSL features and the corresponding cluster indexes.
Neither speech transcription nor time stamp information is required in the
proposed system. It is ASR-free and can potentially avoid the ASR errors effect
in practice. Experimental results carried out on non-native English databases
show that the proposed approach significantly improves the performance in the
"open response" scenario as compared to previous methods and matches the
recently reported performance in the "read aloud" scenario.Comment: Accepted by ICASSP 202
Enhanced strange baryon production in Au+Au collisions compared to p+p at sqrts = 200 GeV
We report on the observed differences in production rates of strange and
multi-strange baryons in Au+Au collisions at sqrts = 200 GeV compared to pp
interactions at the same energy. The strange baryon yields in Au+Au collisions,
then scaled down by the number of participating nucleons, are enhanced relative
to those measured in pp reactions. The enhancement observed increases with the
strangeness content of the baryon, and increases for all strange baryons with
collision centrality. The enhancement is qualitatively similar to that observed
at lower collision energy sqrts =17.3 GeV. The previous observations are for
the bulk production, while at intermediate pT, 1 < pT< 4 GeV/c, the strange
baryons even exceed binary scaling from pp yields.Comment: 7 pages, 4 figures. Printed in PR
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