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Li, Ting

Publications and source records attributed to Li, Ting.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Simulation of compound flooding in Japan using a nationwide model

For this study, a high-resolution, summit-to-sea unstructured-grid model was used to simulate two compound flooding events in different geomorphic settings in Japan: the July 2012 flood in Kumamoto city and July 2018 flood in Okayama City, both caused by a torrential rainfall during seasonal Meiyu front but otherwise exhibiting quite different compound flood characteristics. The model shows good performance in simulating flooding extent; e.g., the Hit Rate for the inundation event in 2018 exceeds 0.9. Sensitivity tests were conducted to determine the roles/significance of levee structures along major rivers in coastal regions. Our results indicate that riverine and oceanic factors as well as levees significantly contribute to the observed flooding extents, and we are able to quantify the contributions from each factor at different locations. The model has been implemented operationally as the first nationwide 3-day compound flooding forecast system for Japan.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Permeability-Engineered Compartmentalization Enables In Vitro Reconstitution of Sustained Synthetic Biology Systems

In nature, biological compartments such as cells rely on dynamically controlled permeability for matter exchange and complex cellular activities. Likewise, the ability to engineer compartment permeability is crucial for in vitro systems to gain sustainability, robustness, and complexity. However, rendering in vitro compartments such a capability is challenging. Here, a facile strategy is presented to build permeability-configurable compartments, and marked advantages of such compartmentalization are shown in reconstituting sustained synthetic biology systems in vitro. Through microfluidics, the strategy produces micrometer-sized layered microgels whose shell layer serves as a sieving structure for biomolecules and particles. In this configuration, the transport of DNAs, proteins, and bacteriophages across the compartments can be controlled an guided by a physical model. Through permeability engineering, a compartmentalized cell-free protein synthesis system sustains multicycle protein production; ≈100 000 compartments are repeatedly used in a five-cycle synthesis, featuring a yield of 2.2 mg mL -1 . Further, the engineered bacteria-enclosing compartments possess near-perfect phage resistance and enhanced environmental fitness. In a complex river silt environment, compartmentalized whole-cell biosensors show maintained activity throughout the 32 h pollutant monitoring. It is anticipated that permeability-engineered compartmentalization should pave the way for practical synthetic biology applications such as green bioproduction, environmental sensing, and bacteria-based therapeutics.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Establishment of time‐resolved fluoroimmunoassay of IgG4 based on magnetic microspheres

Abstract Background The abnormal increase in serum IgG4 level is an important clinical symptom of IgG4‐related disease (IgG4‐RD), and the detection of serum IgG4 level is a powerful tool for the diagnosis of IgG4‐RD. This study was conducted to establish a simple and rapid immunoassay for the determination of human serum IgG4 levels. Methods Based on the competition method, a novel immunoassay was established for the determination of human serum IgG4 using a combination of time‐resolved fluoroimmunoassay (TRFIA) and magnetic microspheres. IgG4 was coupled with magnetic microspheres and competed with IgG4 in the samples to bind the Eu 3+ ‐labeled anti‐IgG4 antibody. The immunocomplex was separated and washed in a magnetic field, and the fluorescence counts were measured according to the number of dissociated europium ions. Results The analytical sensitivity of IgG4‐TRFIA based on magnetic microspheres was 0.006 g/L, and the detection range was 0.006–20 g/L under optimal conditions. The precision, recovery, and specificity of this immunoassay were demonstrated to be acceptable. The clinical application of IgG4‐TRFIA based on magnetic microspheres was evaluated and compared with that of immunonephelometry. The results showed that the two detection methods had a good correlation, with a correlation coefficient of .9871. Conclusion IgG4‐TRFIA based on magnetic microspheres has the advantages of high sensitivity, wide detection range, and short analysis time and has the potential to become a useful tool for the diagnosis of IgG4‐RD.

Wu, Qingqing↗
DOE OSTI2019

The Maunakea Spectroscopic Explorer

The Maunakea Spectroscopic Explorer is a next-generation massively multiplexed spectroscopic facility currently under development in Hawaii. It is completely dedicated to large-scale spectroscopic surveys and will enable transformative science. In this white paper we summarize the science case and describe the current state of the project.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Mediation of plant–mycorrhizal interaction by a lectin receptor-like kinase

The molecular mechanisms underlying mycorrhizal symbioses, the most ubiquitous and impactful mutualistic plant–microbial interaction in nature, are largely unknown. Through genetic mapping, resequencing and molecular validation, we demonstrate that a G-type lectin receptor-like kinase (lecRLK) mediates the symbiotic interaction between Populus and the ectomycorrhizal fungus Laccaria bicolor . Furthermore, this finding uncovers an important molecular step in the establishment of symbiotic plant–fungal associations and provides a molecular target for engineering beneficial mycorrhizal relationships.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Improvement of Al/Steel Tungsten Inert Gas Welding–Brazing Joint by High-Energy Shot Peening

High-energy shot peening treatment was applied to improve the Al/steel tungsten inert gas welding–brazing lap joint. The mechanical properties and microstructure evolution of the joint were investigated. Results showed that the mechanical properties of weld were evidently reinforced due to microstructure transformation of joint surface layer. The grain structure in the joint surface layer was distorted and refined. Large compressive residual stress was introduced into the joint surface, and its hardness obviously increased due to strain hardening. When the peening pressure was 0.15 MPa, the tensile shear strength of the joint reached the maximum value (199.6 MPa), which was 16.5% higher than that of the as-welded joint.

36 MATERIALS SCIENCE↗
DOE OSTI2019

The Detailed Science Case for the Maunakea Spectroscopic Explorer, 2019 edition

(Abridged) The Maunakea Spectroscopic Explorer (MSE) is an end-to-end science platform for the design, execution and scientific exploitation of spectroscopic surveys. It will unveil the composition and dynamics of the faint Universe and impact nearly every field of astrophysics across all spatial scales, from individual stars to the largest scale structures in the Universe. Major pillars in the science program for MSE include (i) the ultimate Gaia follow-up facility for understanding the chemistry and dynamics of the distant Milky Way, including the outer disk and faint stellar halo at high spectral resolution (ii) galaxy formation and evolution at cosmic noon, via the type of revolutionary surveys that have occurred in the nearby Universe, but now conducted at the peak of the star formation history of the Universe (iii) derivation of the mass of the neutrino and insights into inflationary physics through a cosmological redshift survey that probes a large volume of the Universe with a high galaxy density. MSE is positioned to become a critical hub in the emerging international network of front-line astronomical facilities, with scientific capabilities that naturally complement and extend the scientific power of Gaia, the Large Synoptic Survey Telescope, the Square Kilometer Array, Euclid, WFIRST, the 30m telescopes and many more.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Astro2020 Science White Paper: Local Dwarf Galaxy Archaeology

Nearby dwarf galaxies are local analogues of high-redshift and metal-poor stellar populations. Most of these systems ceased star formation long ago, but they retain signatures of their past that can be unraveled by detailed study of their resolved stars. Archaeological examination of dwarf galaxies with resolved stellar spectroscopy provides key insights into the first stars and galaxies, galaxy formation in the smallest dark matter halos, stellar populations in the metal-free and metal-poor universe, the nature of the first stellar explosions, and the origin of the elements. Extremely large telescopes with multi-object R=5,000-30,000 spectroscopy are needed to enable such studies for galaxies of different luminosities throughout the Local Group.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Anomaly analysis and visualization for dynamic networks through spatiotemporal graph segmentations

With recent technology advance in Internet of Things (IoT) that involves human, sensors, and mobile devices, networks are not only growing much larger but more complex and dynamic in nature. The spatiotemporal dynamics of networks are represented by both topological changes and temporal shifts of attribute information associated with network components. Understanding the pattern and trend of dynamic networks is increasingly important. While data mining approaches are generally useful in analyzing the statistical properties of networks, there has been recent trend to consider bringing human into the loop, and to examine how feedback from visualizations of large-scale dynamic networks can further improve data mining and machine learning. Traditional visualization methods based on animation and sequences of snapshot graphs are also limited by human cognitive capability. Here, we present a dynamic network analysis and visualization (DNAV) tool which explores the spatiotemporal dimensions of graph components. In particular, nodes and edges are augmented with spatiotemporal segmentation based on both topological and attribute dynamics (e.g., time and locations of connectivity). To further facilitate analysis of large dynamic networks, DNAV includes statistical dynamic overviews alongside graph views, as well as data filtering modules for scalable analysis. Using case studies on public datasets, we demonstrate the effectiveness of DNAV in understanding and analyzing anomalies in dynamic networks such as computer communication networks.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

High-throughput, one-step screening, cloning and expression based on the lethality of DpnI in Escherichia coli

Highlights: • The extreme toxicity of the DpnI from Streptococcus pneumoniae in bacteria containing Gm6ATC, the product of Dam methylation. • One-step screening, cloning and expression based on the lethality of DpnI in Escherichia coli. • The efficiency of using this method for cloning was approximately 100%. • Rapid one-step selection of soluble proteins. The manipulation of recombinant DNA has been an integral step in molecular biology to date. A number of strategies have been developed over the years, as traditional cloning methods are time consuming, have high backgrounds and low efficiency and are often limited by the number of suitable restriction sites available. Here, we constructed a series of new positive-selection-based cloning vectors that overcome most of the above mentioned drawbacks and can be applied in both eukaryotic and prokaryotic systems. This strategy is based on the extreme toxicity of DpnI in wild-type E. coli and the inactivation of this lethality by the introduction of target gene within multiple cloning sites. There are no rapid approaches for identifying soluble proteins for high-throughput screening. In this study, we combined this highly efficient cloning strategy with rapid identification of soluble proteins to construct vectors with multiple fusion tags, such as MBP, GST, CBD, NusA, and Sumo, to generate enzymes with potential diagnostic, industrial or therapeutic applications. Thus, this versatile positive-selection-based technology is appropriate for routine cloning, DNA library construction, and high-throughput screening for the expression of proteins of interest.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Polar-core spin vortex of quasi-2D ferromagnetic spin-1 condensate in a flat-bottomed optical trap with a weak magnetic field

Motivated by the recent experiments realized in a flat-bottomed optical trap (Navon et al., 2015; Chomaz et al., 2015), we study the ground state of polar-core spin vortex of quasi-2D ferromagnetic spin-1 condensate in a finite-size homogeneous trap with a weak magnetic field. The exact spatial distribution of local spin is obtained with a variational method. Unlike the fully-magnetized planar spin texture with a zero-spin core, which was schematically demonstrated in previous studies for the ideal polar-core spin vortex in a homogeneous trap with infinitely large boundary, some plateaus and two-cores structure emerge in the distribution curves of spin magnitude in the polar-core spin vortex we obtained for the larger effective spin-dependent interaction. More importantly, the spin values of the plateaus are not 1 as expected in the fully-magnetized spin texture, except for the sufficiently large spin-dependent interaction and the weak-magnetic-field limit. We attribute the decrease of spin value to the effect of finite size of the system. The spin values of the plateaus can be controlled by the quadratic Zeeman energy q of the weak magnetic field, which decreases with the increase of q.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Flare Ribbons Approach Observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory

We report flare ribbons approach (FRA) during a multiple-ribbon M-class flare on 2015 November 4 in NOAA AR 12443, obtained by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The flare consisted of a pair of main ribbons and two pairs of secondary ribbons. The two pairs of secondary ribbons were formed later than the appearance of the main ribbons, with respective time delays of 15 and 19 minutes. The negative-polarity main ribbon spread outward faster than the first secondary ribbon with the same polarity in front of it, and thus the FRA was generated. Just before their encounter, the main ribbon was darkening drastically and its intensity decreased by about 70% in 2 minutes, implying the suppression of main-phase reconnection that produced two main ribbons. The FRA caused the deflection of the main ribbon to the direction of secondary ribbon with a deflection angle of about 60°. A post-approach arcade was formed about 2 minutes later and the downflows were detected along the new arcade with velocities of 35–40 km s{sup −1}, indicative of the magnetic restructuring during the process of FRA. We suggest that there are three topological domains with footpoints outlined by the three pairs of ribbons. Close proximity of these domains leads to deflection of the ribbons, which is in agreement with the magnetic field topology.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Simultaneous Observations of p-mode Light Walls and Magnetic Reconnection Ejections above Sunspot Light Bridges

Recent high-resolution observations from the Interface Region Imaging Spectrograph reveal bright wall-shaped structures in active regions (ARs), especially above sunspot light bridges. Their most prominent feature is the bright oscillating front in the 1400/1330 Å channel. These structures are named light walls and are often interpreted to be driven by p-mode waves. Above the light bridge of AR 12222 on 2014 December 06, we observed intermittent ejections superimposed on an oscillating light wall in the 1400 Å passband. At the base location of each ejection, the emission enhancement was detected in the Solar Dynamics Observatory 1600 Å channel. Thus, we suggest that in wall bases (light bridges), in addition to the leaked p-mode waves consistently driving the oscillating light wall, magnetic reconnection could happen intermittently at some locations and eject the heated plasma upward. Similarly, in the second event occurring in AR 12371 on 2015 June 16, a jet was simultaneously detected in addition to the light wall with a wave-shaped bright front above the light bridge. At the footpoint of this jet, lasting brightening was observed, implying magnetic reconnection at the base. We propose that in these events, two mechanisms, p-mode waves and magnetic reconnection, simultaneously play roles in the light bridge, and lead to the distinct kinetic features of the light walls and the ejection-like activities, respectively. To illustrate the two mechanisms and their resulting activities above light bridges, in this study we present a cartoon model.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Novel Hsp90 inhibitor platycodin D disrupts Hsp90/Cdc37 complex and enhances the anticancer effect of mTOR inhibitor

Heat shock protein 90 (Hsp90) is a critically conserved molecular chaperone protein and promising therapeutic target for cancer treatment. In this study, platycodin D (PD), a saponin isolated from traditional Chinese herb Platycodonis Radix, was identified as a novel Hsp90 inhibitor. We verified that PD did not affect the ATPase activity of Hsp90. However, PD disrupted the co-chaperone interaction of Hsp90/cell division cycle protein 37 (Cdc37) and subsequently degraded multiple Hsp90 client proteins without the feedback increase of Hsp70. In different genotypes of non-small cell lung cancer cells, co-treatment with the mTOR inhibitor Everolimus and PD enhanced antiproliferation activity and apoptotic effect. The feedback survival signal upon mTOR inhibition was fully terminated by the co-administration with PD through reduced epidermal growth factor receptor (EGFR) and insulin growth factor 1 receptor (IGF1R) expression, suppressed AKT activity, and reinforced 4E-BP1 inhibition. Our results not only identified PD as a novel Hsp90 inhibitor by disrupting the protein–protein interaction of Hsp90/Cdc37 complex, but also provided mechanistic insights into the ineffectiveness of mTOR inhibitors and identified therapeutic strategy for cancer treatment. - Highlights: • Platycodin D (PD) is a novel Hsp90 inhibitor by disrupting Hsp90/Cdc37 complex. • PD terminated the survival signal induced by mTOR inhibition via feedback blockade. • Combining mTOR inhibitor and PD together exhibited amplified anti-NSCLC effect.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

From 2014 October 19 to 27, six X-class flares occurred in super active region (AR) 12192. They were all confined flares and were not followed by coronal mass ejections. To examine the structures of the four flares close to the solar disk center from October 22 to 26, we firstly employ composite triple-time images in each flare process to display the stratified structure of these flare loops. The loop structures of each flare in both the lower (171 Å) and higher (131 Å) temperature channels are complex, e.g., the flare loops rooting at flare ribbons are sheared or twisted (enwound) together, and the complex structures were not destroyed during the flares. For the first flare, although the flare loop system appears as a spindle shape, we can estimate its structures from observations, with lengths ranging from 130 to 300 Mm, heights from 65 to 150 Mm, widths at the middle part of the spindle from 40 to 100 Mm, and shear angles from 16° to 90°. Moreover, the flare ribbons display irregular movements, such as the left ribbon fragments of the flare on October 22 sweeping a small region repeatedly, and both ribbons of the flare on October 26 moved along the same direction instead of separating from each other. These irregular movements also imply that the corresponding flare loops are complex, e.g., several sets of flare loops are twisted together. Although previous studies have suggested that the background magnetic fields prevent confined flares from erupting,based on these observations, we suggest that complex flare loop structures may be responsible for these confined flares.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Introducing Eu{sup 2+} into yellow phosphor LiBaB{sub 9}O{sub 15}:Ce{sup 3+}, Dy{sup 3+} as blue emitting source to realize white emission

A series of Dy{sup 3+}, Ce{sup 3+}/Dy{sup 3+}, Eu{sup 2+}/Dy{sup 3+} and Ce{sup 3+}/Eu{sup 2+}/Dy{sup 3+} doping LiBaB{sub 9}O{sub 15} (LBB) phosphors were synthesized via a high temperature solid-state method. LBB:Dy{sup 3+} cannot create light under ultraviolet radiation, however, LBB:Ce{sup 3+}, Dy{sup 3+} can produce yellow emission under 295 nm excitation. The energy transfer occurs from Ce{sup 3+} to Dy{sup 3+} ions via electric dipole-dipole interaction and the critical distance is estimated to be 21.15 Å based on concentration quenching model. Generally, Eu{sup 2+} ion is a sensitizer to Dy{sup 3+} ion, however, there is only the emission of Eu{sup 2+} in LBB:Eu{sup 2+}, Dy{sup 3+}, which means there is no energy transfer from Eu{sup 2+} to Dy{sup 3+} ions. Interestingly enough, when doping Eu{sup 2+} ion into LBB:Ce{sup 3+}, Dy{sup 3+}, white emission can be achieved by increase the blue (350–425 nm) emission intensity. The spectral property, quantum efficiency, CIE chromaticity coordinates and thermal quenching property of LBB:Ce{sup 3+}, Eu{sup 2+}, Dy{sup 3+} are investigated. The results indicate that LBB:Ce{sup 3+}, Eu{sup 2+}, Dy{sup 3+} may be a potential application to white light emitting diodes. - Graphical abstract: LBB:Ce{sup 3+}, Dy{sup 3+} can create white emission by doping Eu{sup 2+} ions. - Highlights: • LBB:Ce{sup 3+}, Dy{sup 3+} can produce white emission by doping Eu{sup 2+} ion. • There is no energy transfer from Eu{sup 2+} to Dy{sup 3+} ions. • Energy transfer occurs from Ce{sup 3+} to Dy{sup 3+} ions. • LBB:Ce{sup 3+}, Eu{sup 2+}, Dy{sup 3+} may be a potential application for white LEDs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Interaction of Two Active Region Filaments Observed by NVST and SDO

Using high spatial and temporal resolution H α data from the New Vacuum Solar Telescope (NVST) and simultaneous observations from the Solar Dynamics Observatory , we present the rare event of the interaction between two filaments (F1 and F2) in AR 11967 on 2014 January 31. The adjacent two filaments were almost perpendicular to each other. Their interaction was driven by the movement of F1 and started when the two filaments collided with each other. During the interaction, the threads of F1 continuously slipped from the northeast to the southwest, and were accompanied by the brightenings at the junction of two filaments and the northeast footpoint of F2. Part of F1 and the main body of F2 became invisible in H α wavelength due to the heating and the motion of F2. At the same time, bright material initiated from the junction of two filaments were observed to move along F1. The magnetic connectivities of F1 were found to be changed after their interaction. These observations suggest that magnetic reconnection was involved in the interaction of two filaments and resulted in the eruption of one filament.

79 ASTRONOMY AND ASTROPHYSICS↗