168 results on '"Guoqing Lin"'
Search Results
52. Additional file 1 of Interleukin-6-knockdown of chimeric antigen receptor-modified T cells significantly reduces IL-6 release from monocytes
- Author
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Liqing Kang, Xiaowen Tang, Zhang, Jian, Minghao Li, Xu, Nan, Qi, Wei, Jingwen Tan, Xiaoyan Lou, Yu, Zhou, Juanjuan Sun, Zhenkun Wang, Haiping Dai, Chen, Jia, Guoqing Lin, Depei Wu, and Yu, Lei
- Subjects
immune system diseases ,hemic and lymphatic diseases ,hemic and immune systems ,chemical and pharmacologic phenomena - Abstract
Additional file 1: Figure S1. CD19 expression in Raji and K562-CD19-LUC cells and CD14 expression in monocytes. A CD19 expression on Raji cells used for the mouse xenograft model and in vitro cytotoxicity assay. B CD14 expression in monocytes, as detected by flow cytometry.
- Published
- 2020
- Full Text
- View/download PDF
53. The Source‐Specific Station Term and Waveform Cross‐Correlation Earthquake Location Package and Its Applications to California and New Zealand
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Guoqing Lin
- Subjects
Geophysics ,010504 meteorology & atmospheric sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Seismology ,Geology ,0105 earth and related environmental sciences ,Term (time) ,Waveform cross correlation ,Earthquake location - Published
- 2018
54. Seismic velocity structure and characteristics of induced seismicity at the Geysers Geothermal Field, eastern California
- Author
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Guoqing Lin and Bateer Wu
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010504 meteorology & atmospheric sciences ,Renewable Energy, Sustainability and the Environment ,Geothermal reservoir ,Geology ,Induced seismicity ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,Enhanced geothermal system ,01 natural sciences ,Field (geography) ,Seismic velocity ,Reflection (physics) ,Period (geology) ,Geothermal gradient ,Seismology ,0105 earth and related environmental sciences - Abstract
We present a newly developed three-dimensional seismic velocity model, high-precision earthquake relocations and focal mechanisms near the Geysers Geothermal Field in eastern California using seismic data recorded by the Northern California Earthquake Data Center from 1984 to 2015. The velocity model generally agrees with those in previous studies with the Vp model mainly corresponding to rock composition and the Vp/Vs model more correlated with fluid content. The dominating low Vp/Vs anomalies observed from 0 to 4 km depth below sea level is a reflection of the geothermal reservoir. The waveform cross-correlation relocated seismicity shows both spatial and temporal correlations with the geothermal operations in the study area, indicating that they are induced seismicity. Although the focal solutions are dominated by normal and strike-slip regimes throughout our entire study time period, there has been an increase in reverse faulting since 2008, which may be caused by the thermal contraction associated with the Northwest Geysers Enhanced Geothermal System project between 2008 and 2012. Our study provides a groundwork for future seismological studies in The Geysers.
- Published
- 2018
55. Supramolecular Hydrogel with Orthogonally Responsive R/G/B Fluorophores Enables Multi‐Color Switchable Biomimetic Soft Skins
- Author
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Zhenkuang Lei, Lei Zhou, Tao Chen, Guoqing Lin, Muqing Si, Hao Liu, Huiyu Qiu, Wei Lu, and Shuxin Wei
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Biomaterials ,Materials science ,Electrochemistry ,Supramolecular chemistry ,Nanotechnology ,Aggregation-induced emission ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2021
56. On-Orbit Line Spread Function Estimation of the SNPP VIIRS Imaging System From Lake Pontchartrain Causeway Bridge Images
- Author
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Robert E. Wolfe, James C. Tilton, and Guoqing Lin
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Atmospheric Science ,Visible Infrared Imaging Radiometer Suite ,Detector ,0211 other engineering and technologies ,02 engineering and technology ,01 natural sciences ,010309 optics ,Feature (computer vision) ,0103 physical sciences ,Orbit (dynamics) ,Satellite ,Causeway ,Computers in Earth Sciences ,Image resolution ,Geology ,021101 geological & geomatics engineering ,Remote sensing ,Line Spread Function - Abstract
The visible infrared imaging radiometer suite (VIIRS) instrument was launched on October 28, 2011 onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite. The VIIRS instrument is a whiskbroom system with 22 spectral and thermal bands split between 16 moderate resolution bands (M-bands), five imagery resolution bands (I-bands), and a day–night band. In this study, we estimate the along-scan line spread function (LSF) of the I-bands and M-bands based on measurements performed on images of the Lake Pontchartrain Causeway Bridge. In doing so, we develop a model for the LSF that closely matches the prelaunch laboratory measurements. We utilize VIIRS images co-geolocated with a Landsat TM image to precisely locate the bridge linear feature in the VIIRS images as a linear best fit to a straight line. We then utilize nonlinear optimization to compute the best fit equation of the VIIRS image measurements in the vicinity of the bridge to the developed model equation. From the found parameterization of the model equation, we derive the full-width at half-maximum as an approximation of the sensor field of view for all bands, and compare these on-orbit measured values with prelaunch laboratory results.
- Published
- 2017
57. Numerical investigation of temperature distribution and melt pool dimension during dissimilar laser welding of AISI 304 and pure copper
- Author
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Dai Shi, Guoqing Lin, and Song Gao
- Subjects
Heat-affected zone ,Materials science ,Biomedical Engineering ,Laser beam welding ,chemistry.chemical_element ,Welding ,Copper ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry ,law ,Heat transfer ,Composite material ,Material properties ,Instrumentation ,Intensity (heat transfer) ,Beam (structure) - Abstract
In this research, the numerical simulation of the heat transfer phenomenon in dissimilar laser welding was performed. Metals of stainless steel 304 (AISI 304) and pure copper in the moving state were exposed to laser energy, and an asymmetric thermal field was obtained. The cross-sectional area of the concentrated beam and its intensity distribution were considered circular and Gaussian, respectively. Physical properties of metals, depending on temperature and thermophysical changes in the material properties, were considered. Different temperature distributions were obtained by changing various parameters, such as focal length, welding speed, and power; the obtained results were then compared with the experimental ones. The results showed that the molten pool formation was asymmetric and deviated toward the AISI 304 sheet. The heat affected zone (HAZ) was also more toward the AISI 304 sheet. The increase of the molten pool dimensions was much more significant due to the enhancement in the average power, as compared to the other parameters, thus indicating that the average power was a key factor increasing the dimensions of the molten pool. The results of the numerical simulation were consistent with the experimental results, proving their correctness.
- Published
- 2021
58. Green synthesis of stable platinum nanoclusters with enhanced peroxidase-like activity for sensitive detection of glucose and glutathione
- Author
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Xianbing Ji, Longgang Wang, Xiaoyu Zhang, Weili Xue, Liyuan Fan, Shengfu Chen, Kai Liu, Guanglong Ma, and Guoqing Lin
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Detection limit ,chemistry.chemical_classification ,Reducing agent ,010401 analytical chemistry ,02 engineering and technology ,Glutathione ,021001 nanoscience & nanotechnology ,Polysaccharide ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Catalytic oxidation ,chemistry ,X-ray photoelectron spectroscopy ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Hydrogen peroxide ,Spectroscopy ,Nuclear chemistry - Abstract
The sensitive and facile detection of the concentration of glucose and glutathione (GSH) is important for our health. In this work, lily polysaccharide (LP) stabilized platinum nanoclusters (Ptn-LP NCs) were prepared by a facile synthetic strategy where LP was used as a reducing agent and stabilizer. The successful preparation of 1–2 nm platinum nanoclusters (Pt NCs) inside of Ptn-LP NCs was confirmed using UV–Vis spectra, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM), respectively. Furthermore, Ptn-LP NCs accelerated the catalytic oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) in the presence of hydrogen peroxide (H2O2), indicating their intrinsic peroxidase-like activity. The Vm values of TMB and H2O2 were 50.3 × 10−8 Ms−1 and 10.2 × 10−8 Ms−1, respectively, which were higher than those of other mimetic enzymes. The peroxidase-like property of Ptn-LP NCs was used to sensitively detect the concentration of glucose and glutathione (GSH). The detection limits of glucose and GSH were as low as 1.89 and 0.37 μM, the linear ranges of glucose and GSH were 2.5–1000 and 4–140 μM, respectively. The colorimetric method was successfully applied to detect GSH concentration in human serum. This method has great potential application in bio-related detection in the future.
- Published
- 2021
59. Absence of remote earthquake triggering within the Coso and Salton Sea geothermal production fields
- Author
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Yan Qin, Xiaowei Chen, Shimon Wdowinski, Qiong Zhang, Zhongwen Zhan, and Guoqing Lin
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010504 meteorology & atmospheric sciences ,Induced seismicity ,010502 geochemistry & geophysics ,Earthquake swarm ,01 natural sciences ,Pore water pressure ,Geophysics ,Fracture (geology) ,Fluid dynamics ,medicine ,General Earth and Planetary Sciences ,Flushing ,Extraction (military) ,medicine.symptom ,Petrology ,Geothermal gradient ,Geology ,Seismology ,0105 earth and related environmental sciences - Abstract
Geothermal areas are long recognized to be susceptible to remote earthquake triggering, probably due to the high seismicity rates and presence of geothermal fluids. However, anthropogenic injection and extraction activity may alter the stress state and fluid flow within the geothermal fields. Here we examine the remote triggering phenomena in the Coso geothermal field and its surrounding areas to assess possible anthropogenic effects. We find that triggered earthquakes are absent within the geothermal field but occur in the surrounding areas. Similar observation is also found in the Salton Sea geothermal field. We hypothesize that continuous geothermal operation has eliminated any significant differential pore pressure between fractures inside the geothermal field through flushing geothermal precipitations and sediments out of clogged fractures. To test this hypothesis, we analyze the pore-pressure-driven earthquake swarms, and they are found to occur outside or on the periphery of the geothermal production field. Therefore, our results suggest that the geothermal operation has changed the subsurface fracture network, and differential pore pressure is the primary controlling factor of remote triggering in geothermal fields.
- Published
- 2017
60. Impact of Spatial Sampling on Continuity of MODIS–VIIRS Land Surface Reflectance Products: A Simulation Approach
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Sadashiva Devadiga, Eric Vermote, Miguel O. Román, Guoqing Lin, Xiaoxiong Xiong, S. Sarkar, Nima Pahlevan, and Robert E. Wolfe
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Visible Infrared Imaging Radiometer Suite ,010504 meteorology & atmospheric sciences ,Meteorology ,0211 other engineering and technologies ,Atmospheric correction ,Sampling (statistics) ,02 engineering and technology ,01 natural sciences ,Normalized Difference Vegetation Index ,General Earth and Planetary Sciences ,Environmental science ,Satellite ,Bidirectional reflectance distribution function ,Electrical and Electronic Engineering ,Scale (map) ,Zenith ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Abstract
With the increasing need to construct long-term climate-quality data records to understand, monitor, and predict climate variability and change, it is vital to continue systematic satellite measurements along with the development of new technology for more quantitative and accurate observations. The Suomi National Polar-orbiting Partnership mission provides continuity in monitoring the Earth's surface and its atmosphere in a similar fashion as the heritage MODIS instruments onboard the National Aeronautics and Space Administration's Terra and Aqua satellites. In this paper, we aim at quantifying the consistency of Aqua MODIS and Suomi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Reflectance (LSR) and NDVI products as related to their inherent spatial sampling characteristics. To avoid interferences from sources of measurement and/or processing errors other than spatial sampling, including calibration, atmospheric correction, and the effects of the bidirectional reflectance distribution function, the MODIS and VIIRS LSR products were simulated using the Landsat-8's Operational Land Imager (OLI) LSR products. The simulations were performed using the instruments' point spread functions on a daily basis for various OLI scenes over a 16-day orbit cycle. It was found that the daily mean differences due to discrepancies in spatial sampling remain below 0.0015 (1%) in absolute surface reflectance at subgranule scale (i.e., OLI scene size). We also found that the MODIS–VIIRS product intercomparisons appear to be minimally impacted when differences in the corresponding view zenith angles (VZAs) are within the range of $-\!\!15^{\circ}$ to $-35^{\circ}$ $(\textrm{VZA}_{V}-\textrm{VZA}_{M})$ , where VIIRS and MODIS footprints resemble in size. In general, depending on the spatial heterogeneity of the OLI scene contents, per-grid-cell differences can reach up to 20%. Further spatial analysis of the simulated NDVI and LSR products revealed that, depending on the user accuracy requirements for product intercomparisons, spatial aggregations may be used. It was found that if per-grid-cell differences on the order of 10% (in LSR or NDVI) are tolerated, the product intercomparisons are expected to be immune from differences in spatial sampling.
- Published
- 2017
61. Network Coding Scheme Based on Key Nodes.
- Author
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Guoqing Lin, Jing Wang 0066, and Xinmei Wang
- Published
- 2007
- Full Text
- View/download PDF
62. Thirty-six combined years of MODIS geolocation trending
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Robert E. Wolfe, Ping Zhang, Guoqing Lin, James C. Tilton, John J. Dellomo, and Bin Tan
- Subjects
Geolocation ,Visible Infrared Imaging Radiometer Suite ,Radiometer ,Equator ,Nadir ,Environmental science ,Satellite orbit ,Moderate-resolution imaging spectroradiometer ,Remote sensing - Abstract
Two Moderate Resolution Imaging Spectroradiometer (MODIS) sensors have been in operations for more than 19 and 17 years (thus 36 combined years) as part of NASA's Earth Observing System (EOS) on the Terra platform that was launched in December 1999 and on the Aqua platform that was launched in May 2002, respectively. Accurate geolocation is a critical element needed for accurate retrieval of global biogeophysical parameters. In this paper, we describe the latest trends in the continuously improved MODIS geolocation accuracy in Collection-5 (C5), C6 and C6.1 re-processing and forward-processing data streams. We improved geolocation accuracy in the re-processed data and corrected for geolocation biases found in forward-processed data, including those caused by operations such as the stop-go-stop status of the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) instrument on the Aqua platform. We discuss scan-toscan underlaps near nadir over the equator regions that was discovered in checking the non-underlapping requirement in the Visible Infrared Imaging Radiometer Suite (VIIRS) based on trending parameters from the actual Suomi National Polar-orbiting Partnership (S-NPP) satellite orbit. The underlaps are closely tied to instrument effective focal length that is measured from on-orbit data using a technique we recently developed. We also discuss potential improvements for the upcoming C7 re-processing.
- Published
- 2019
63. The Ridgecrest earthquakes: Torn ground, nested foreshocks, Garlock shocks, and Temblor’s forecast
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Guoqing Lin, Chris Rollins, Deborah Kilb, and Ross S. Stein
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Seismology ,Geology ,Foreshock - Published
- 2019
64. InSAR observations of lake loading at Yangzhuoyong Lake, Tibet: Constraints on crustal elasticity
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Marie-Pierre Doin, Shimon Wdowinski, Guoqing Lin, Falk Amelung, Timothy H. Dixon, and Wenliang Zhao
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Unit response ,010504 meteorology & atmospheric sciences ,Modulus ,Crust ,Young's modulus ,Surface loading ,010502 geochemistry & geophysics ,01 natural sciences ,symbols.namesake ,Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,Interferometric synthetic aperture radar ,Vertical direction ,Earth and Planetary Sciences (miscellaneous) ,symbols ,Elasticity (economics) ,Geology ,Seismology ,0105 earth and related environmental sciences - Abstract
We use Envisat 2003–2010 InSAR imagery over Yangzhuoyong Lake in southeastern Tibet to study the elastic response of the Earth's crust to variations in lake level. The net lake level drop during our study period is ∼3 m with seasonal variations of more than 1 m. The time-series close to the lake center shows a high correlation with the lake level history. Near the lake center the unit response with respect to lake level change is 2.5 mm/m in radar line-of-sight direction, or ∼2.7 mm/yr in vertical direction, corresponding to a vertical response of ∼4.3 mm/Gt load change. We show that the observations are most sensitive to the elastic properties of the crust in the 5–15 km depth range and explain them with a layered elastic half-space model with a Young's modulus of 50 ± 9 GPa Young's modulus in the top 15 km of the crust and using moduli inferred from seismology at greater depth. The inferred Young's modulus is ∼25% smaller than the seismic modulus, which we attribute to damaged rock and the presence of fluids.
- Published
- 2016
65. Chemical mechanism of flocculation and deposition of clay colloids in coastal aquifers
- Author
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Xiaolan Chen, Lixia Qiu, Honglu Pang, Jun Zhou, Guoqing Lin, and Xiaoyun Yan
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inorganic chemicals ,geography ,Flocculation ,geography.geographical_feature_category ,0208 environmental biotechnology ,Mineralogy ,Ocean Engineering ,Aquifer ,02 engineering and technology ,010501 environmental sciences ,Oceanography ,complex mixtures ,01 natural sciences ,020801 environmental engineering ,Permeability (earth sciences) ,Colloid ,Ionic strength ,Particle size ,Interception ,Porous medium ,Geology ,0105 earth and related environmental sciences - Abstract
Seawater intrusion has become one of serious environmental problems in coastal areas. During the replacement of saline water by fresh water in the aquifers, in-situ clay could be released, transport and deposit in the porous media due to the change of hydrodynamic and geochemical conditions, which resulted in the increasing of particle size, plugging of pores and reduction of the permeability. Batch experiments and sand column experiments were explored to study the relationships between the flocculation of in-situ clay and geochemical conditions, by changing ionic strength and ionic type of clay suspension. Column outflow was analyzed for suspended particles and electrical conductivity. The total percentage of colloid straining and interception distribution in porous media was calculated. The results indicate that porous media had an effect on the interception of clay colloid particles with about 10 percent clay colloids captured due to the rough surfaces and spatial structure of porous media. Ionic strength played a key role on the permeability reductions. The higher ionic strength is, the greater the amount of colloidal particles trapped. Ionic type also had a significant effect on the interception of clay colloid particles. Ripening was the main mechanism for the interception within porous media when the bulk solution was potassium chloride while blocking happened when the bulk solution was sodium chloride. The distribution of clay colloids in porous media was heterogeneous. The closer to the sand column inlet was the less interception of clay colloids was. The results can provide the scientific basis for preventing the water sensitivity during the process of salty aquifer restoration.
- Published
- 2016
66. A large refined catalog of earthquake relocations and focal mechanisms for the Island of Hawai'i and its seismotectonic implications
- Author
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Guoqing Lin and Paul G. Okubo
- Subjects
Focal mechanism ,Shear waves ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Ray tracing (physics) ,Geophysics ,Amplitude ,Volcano ,Space and Planetary Science ,Geochemistry and Petrology ,Observatory ,Earth and Planetary Sciences (miscellaneous) ,Caldera ,Geology ,Seismology ,0105 earth and related environmental sciences ,Earthquake location - Abstract
We present high-quality focal mechanisms based on a refined earthquake location catalog for the Island of Hawai'i, focusing on Mauna Loa and Kīlauea volcanoes. The relocation catalog is based on first-arrival times and waveform data of both compressional and shear waves for about 180,000 events on and near the Island of Hawai'i between 1986 and 2009 recorded by the seismic stations at the Hawaiian Volcano Observatory. We relocate all the earthquakes by applying ray tracing through an existing three-dimensional velocity model, similar event cluster analysis, and a differential-time relocation method. The resulting location catalog represents an expansion of previous relocation studies, covering a longer time period and consisting of more events with well-constrained absolute locations. The focal mechanisms are obtained based on the compressional-wave first-motion polarities and compressional-to-shear wave amplitude ratios by applying the HASH program to the waveform cross correlation relocated earthquakes. Overall, the good-quality (defined by the HASH parameters) focal solutions are dominated by normal faulting in our study area, especially in the active Ka'ōiki and Hīlea seismic zones. Kīlauea caldera is characterized by a mixture of approximately equal numbers of normal, strike-slip, and reverse faults, whereas its south flank has slightly fewer strike-slip events. Our relocation and focal mechanism results will be useful for mapping the seismic stress and strain fields and for understanding the seismic-volcanic-tectonic relationships within the magmatic systems.
- Published
- 2016
67. Local earthquake tomography with the inclusion of full topography and its application to Kīlauea volcano, Hawai'i
- Author
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Peng Li and Guoqing Lin
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Gabbro ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Geophysics ,Volcano ,Sill ,Geochemistry and Petrology ,Seismic tomography ,Ultramafic rock ,Caldera ,Rift zone ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
We develop a new three-dimensional local earthquake tomography algorithm with the inclusion of full topography (LETFT). We present both synthetic and real data tests based on the P- and S-wave arrival time data for Kīlauea volcano in Hawai'i. A total of 33,768 events with 515,711 P-picks and 272,217 S-picks recorded by 35 stations at the Hawaiian Volcano Observatory are used in these tests. The comparison between the new and traditional methods based on the synthetic test shows that our new algorithm significantly improves the accuracy of the velocity model, especially at shallow depths. In the real data application, the P- and S-wave velocity models of Kīlauea show several intriguing features. We observe discontinuous high Vp (> 7.0 km/s) and Vs (> 3.9 km/s) zones at 5–14 km depth below Kīlauea caldera, its East Rift Zone (ERZ) and the Southwest Rift Zone, which may represent consolidated intrusive gabbro-ultramafic cumulates. At Kīlauea caldera, Vp and Vs decrease from ~ 3.9 km/s and ~ 2.6 km/s from the surface to ~ 3.7 km/s and ~ 2.3 km/s at 2 km depth. We resolve a high Vp zone (> 7.0 km/s) at 5–14 km depth and high Vs zone (> 3.9 km/s) at 5–11 km depth. This high Vp and Vs zone extends to the north of the ERZ at 5–10 km depth and to the upper ERZ at 8–12 km depth. In the Hilina Fault System, there is a high Vp layer (~ 7.0 km/s) at 4–6 km depth and a low Vp body of ~ 5.7 km/s at 6–11 km depth. The high Vp layer could be associated with the intrusive ultramafic gabbro sills. The velocity contrast on the north and south sides of the Koa'e Fault System indicates that the intrusive activities mainly occur to the north of the fault. Our new LETFT method performs well in both the synthetic and real data tests and we expect that it will reveal more robust velocity structures in areas with larger topographic variations.
- Published
- 2016
68. A laboratory column study on particles release in remediation of seawater intrusion region
- Author
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Lei Gong, Peidong Zhang, Guoqing Lin, Jianbo Liu, and Jun Zhou
- Subjects
geography ,geography.geographical_feature_category ,Environmental remediation ,Mineralogy ,Ocean Engineering ,Aquifer ,engineering.material ,Oceanography ,Salinity ,Permeability (earth sciences) ,Ionic strength ,Illite ,engineering ,Clay minerals ,Geology ,Groundwater - Abstract
In coastal areas, excessive exploitation of groundwater causes seawater intrusion. In artificial recharge of aquifer remediation process, the replacement of saltwater and freshwater with each other causes colloid release, and permeability also decreases. In this paper, the aquifer samples containing minimal clay mineral (mainly illite) in Dagu River aquifer were used. Adopting horizontal column experiments, we studied the influences of seepage velocity and ionic strength on particle release, as well as the relationship between them. In the column experiments, the Critical Salt Concentration (CSC) of the Dagu River aquifer was determined as 0.05 mol L−1 approximately. This result was basically consistent with the DLVO theoretical calculation. For the constant seepage velocity, the salinity descending rate and partical release were slower, and the peak of particle concentration was lower. However, the total amount of released particles was almost constant at different salinity descending rate. For constant salinity descending rates, the peak of particle concentration decreased as seepage velocity increased, but the total amount of released particles rose up. The experiments also indicated the existence of a critical seepage velocity, which dropped with the decrease of salt concentration. When the concentration of NaCl solution decreased from 0.17 mol L−1 to 0.06 mol L−1, the critical seepage velocity decreased from 3 cm min−1 to 2.5 cm min−1, which is consistent to the results predicted by DLVO theory.
- Published
- 2015
69. Location and size of the shallow magma reservoir beneath Kīlauea caldera, constraints from near‐sourceVp/Vsratios
- Author
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Falk Amelung, Paul G. Okubo, Guoqing Lin, and Peter M. Shearer
- Subjects
Geophysics ,Impact crater ,Shear (geology) ,Wave velocity ,General Earth and Planetary Sciences ,Caldera ,Rift zone ,Petrology ,Geology ,Seismology - Abstract
We present high-resolution compressional wave to shear wave velocity ratios (Vp/Vs) beneath Kīlauea’s summit caldera by applying an in situ estimation method using waveform cross-correlation data for three similar earthquake clusters. We observe high Vp/Vs ratios (1.832 and 1.852) for two event clusters surrounded by the low background Vp/Vs value of 1.412 at ∼2.1 km depth below the surface. These high and low Vp/Vs ratios can be explained by melt- and CO2-filled cracks, respectively, based on a theoretical crack model. The event cluster with the highest Vp/Vs ratio consists of long-period events that followed the 1997 East Rift Zone eruption, indicating their association with fluid and magma movement. The depths of the two clusters with high Vp/Vs ratios are consistent with the magma reservoir location inferred from geodetic observations. Their locations east and north of Halema‘uma‘u crater suggest a horizontal extent of a few kilometers for the reservoir.
- Published
- 2015
70. Study on Adsorption-Desorption of Benzene in Soil
- Author
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Jing Sun, Xiaomeng Tang, Zhu Henghua, Guoqing Lin, and Lichun Zhang
- Subjects
Pollutant ,chemistry.chemical_compound ,Adsorption ,Petrochemical ,Chemistry ,Environmental chemistry ,Desorption ,Groundwater remediation ,General Medicine ,General Chemistry ,Particle size ,Benzene ,Groundwater - Abstract
Groundwater near the Qilu petrochemical plant in Zibo City is polluted by oil for over thirty years, which seriously threaten the local ecological environment. The results of GC-MS analysis of water samples show that benzene was the most abundant and toxic organic pollutant. The adsorption-desorption behaviour of benzene in soil was studied through batch experiments. The results indicated that the adsorption amount of benzene in the local soil showed a trend of increasing first and then decreasing with the increasing of the initial concentration of benzene. There existed an optimal initial concentration of benzene in the adsorption experiments. The desorption concentration of benzene was proportional to the initial concentration of benzene. Particle size of the soil was inversely related to adsorption and desorption concentration of benzene. The soil with the average particle size of 0.08 mm had the largest adsorption capacity for benzene, which could reach 376.39 mg/kg. The results could provide a theoretical basis for the local groundwater remediation.
- Published
- 2020
71. Pollution of Microplastics in Coastal Plain of the Huangshui River Basin
- Author
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Mogeng Cheng, Guoqing Lin, Sifan Zhou, Sheng Su, and Qiyun Lin
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Pollution ,Microplastics ,geography ,geography.geographical_feature_category ,Soil test ,Coastal plain ,media_common.quotation_subject ,Drainage basin ,Environmental chemistry ,Environmental science ,Particle size ,Mulch ,Bay ,media_common - Abstract
Marine microplastic pollution is one of the hot spots in current marine environment research. The coastal zone has unique micro-plastic pollution characteristics at the junction of land and sea, and the micro-plastic pollution in the coastal zone soil is still unclear. In this study, Huangshui river basin was selected as the research area in Laizhou Bay, China. Soil samples were collected from the depth of 0-3, 3-6 and 6-9 cm at each location. Microplastics were separated by flotation. Microplastic characteristics were investigated and analyzed by Nile red staining and Fourier infrared spectrometer. The results showed that there was slight microplastic pollution in the coastal plain. 92.9% of the detected microplastics were granular, 6.1% were fibers, and only 1.0% were films. Microplastics with a particle size of 20-100 μm accounted for 57.9% of the total, particles with the size of 100-1000 μm accounted for 38.6%, and particles with the size of 1000-5000 μm accounted for 3.5%. The presence of film-like PE was detected, indicating that microplastic contamination in the soil was likely to come from the utilization and mulching of agricultural mulch. The amount of microplastics in soil was related to the size of microplastics. Abundance of microplastics in soil increased with decreasing of the size of soil. In addition, the microplastic content in soil decreased, and particles with a smaller size occupied a larger proportion, with the increasing of the depth of soil.
- Published
- 2020
72. Spatiotemporal variations of in situ V/V ratio within the Salton Sea Geothermal Field, southern California
- Author
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Guoqing Lin
- Subjects
In situ ,Shore ,geography ,Spatial correlation ,geography.geographical_feature_category ,Renewable Energy, Sustainability and the Environment ,0211 other engineering and technologies ,Geology ,Soil science ,02 engineering and technology ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Field (geography) ,Injection volume ,Extraction (military) ,021108 energy ,Geothermal gradient ,Heat flow ,0105 earth and related environmental sciences - Abstract
The Salton Sea Geothermal Field is located on the southeastern shore of Salton Sea and has been facilitated with many geothermal units in the past few decades. In this study, I investigate possible effects of the long-term production process on seismic parameters by using a high-resolution approach to estimate the near-source compressional- to shear-wave velocity ratios (Vp/Vs). I apply this method to similar earthquake clusters based on waveform cross-correlation data and obtain robust results for six event clusters in the study area. The resulting in situ Vp/Vs ratios vary from 1.510 to 1.811 with the calculated uncertainties below 0.02. I examine possible relations between these Vp/Vs ratios and other types of data. The observed spatial correlation with the heat flow and temporal correlation with well production data indicate that the near-source Vp/Vs ratios strongly depend on the subsurface natural properties, but are influenced by the amount of extraction and injection volume throughout the operational period. This study suggests that the in situ estimation method can be used to detect changes in near-source Vp/Vs ratios caused by exploitation of geothermal areas and is a potentially valuable tool for geothermal resource monitoring.
- Published
- 2020
73. Three-Dimensional P-wave Velocity Structure of the Zhuxi Ore Deposit, South China Revealed by Control-Source First-Arrival Tomography
- Author
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Tao Wang, Lili Song, Yunpeng Zhang, Baoshan Wang, Guoqing Lin, Yongpeng Ouyang, Rucheng Wang, and Shanhui Xu
- Subjects
Dense array ,lcsh:Mineralogy ,lcsh:QE351-399.2 ,South china ,010504 meteorology & atmospheric sciences ,P wave ,Geochemistry ,Geology ,Zhuxi ore deposit ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,body wave tomography ,Mineral exploration ,Tectonics ,control source ,Seismic tomography ,Carboniferous ,Tomography ,dense array ,0105 earth and related environmental sciences - Abstract
The Zhuxi ore deposit, located in Jiangxi province, South China, is the largest tungsten reserve in the world. To better understand the geological structure and distribution of orebodies, we conducted a high resolution three-dimensional P-wave velocity tomography of the uppermost 0.5 km beneath the Zhuxi ore deposit and adjacent area. Our velocity model was derived from 761,653 P-wave first arrivals from 998 control-source shots, recorded by a dense array. As the first 3D P-wave velocity structure of the Zhuxi ore deposit, our model agrees with local topographic and tectonic structures and shows depth-dependent velocity similar to laboratory measurements. The Carboniferous formations hosting the proven orebodies are imaged as high velocities. The high-velocity anomalies extend to a larger area beyond the proven orebodies, and the locations of high&ndash, low velocity boundaries are in accordance with the boundaries between the Neoproterozoic formation and the Carboniferous&ndash, Triassic formation. Seismic tomography reveals that high-velocity anomalies are closely related to the mineralized areas. Our results are helpful for further evaluating the total reserves and suggest that seismic tomography can be a useful tool for mineral exploration.
- Published
- 2020
74. JPSS-1/NOAA-20 VIIRS early on-orbit geometric performance
- Author
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James C. Tilton, Guoqing Lin, John J. Dellomo, Bin Tan, Robert E. Wolfe, and Ping Zhang
- Subjects
Geolocation ,Computer science ,Multiple applications ,Orbit (dynamics) ,Calibration ,Satellite ,Satellite system ,Geometric modeling ,Rapid response ,Remote sensing - Abstract
The first NOAA/NASA Join Polar Satellite System (JPSS-1) satellite was successfully launched on November 18, 2017,becoming NOAA-20. Instruments on-board the NOAA-20 satellite include the Visible Infrared Imaging RadiometerSuite (VIIRS). This instrument is the second build of VIIRS, with the first flight instrument on-board NASA/NOAASuomi National Polar-orbiting Partnership (SNPP) satellite operating since October 2011. The purpose of these VIIRSinstruments is to continue the long-term measurements of biogeophysical variables for multiple applications includingweather forecasting, rapid response and climate research. The geometric performance of VIIRS is essential to retrievingaccurate biogeophysical variables. This paper describes the early on-orbit geometric performance of the JPSS-1/NOAA-20 VIIRS. It first discusses the on-orbit orbit and attitude performance, a key input needed for accurate geolocation. Itthen discusses the on-orbit geometric characterization and calibration of VIIRS and an initial assessment of thegeometric accuracy. It follows with a discussion of an improvement in the instrument geometric model that correctssmall geometrical artifacts that appear in the along-scan direction. Finally, this paper discusses on-orbit measurements ofthe focal length and the impact of this on the scan-to-scan underlap/overlap.
- Published
- 2018
75. Combustion and Emission Performances of Diesel Engine Fueled With Biodiesel-Methanol Blend Fuels
- Author
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Guoqing Lin, Qi Guo, Pankun Song, and Junliang Song
- Subjects
General Energy - Published
- 2015
76. Seismic tomography of compressional wave attenuation structure for Kı̄lauea Volcano, Hawai‘i
- Author
-
Guoqing Lin, Paul G. Okubo, Falk Amelung, and Peter M. Shearer
- Subjects
geography ,geography.geographical_feature_category ,Attenuation ,Volcanology ,Geophysics ,Amplitude ,Volcano ,Space and Planetary Science ,Geochemistry and Petrology ,Seismic tomography ,Earth and Planetary Sciences (miscellaneous) ,Rift zone ,Seismology ,Longitudinal wave ,Geology ,Earthquake location - Abstract
We present a frequency-independent three-dimensional (3-D) compressional wave attenuation model (indicated by the reciprocal of quality factor Qp) for Kilauea Volcano in Hawai‘i. We apply the simul2000 tomographic algorithm to the attenuation operator t* values for the inversion of Qp perturbations through a recent 3-D seismic velocity model and earthquake location catalog. The t* values are measured from amplitude spectra of 26708 P wave arrivals of 1036 events recorded by 61 seismic stations at the Hawaiian Volcanology Observatory. The 3-D Qp model has a uniform horizontal grid spacing of 3 km, and the vertical node intervals range between 2 and 10 km down to 35 km depth. In general, the resolved Qp values increase with depth, and there is a correlation between seismic activity and low-Qp values. The area beneath the summit caldera is dominated by low-Qp anomalies throughout the entire resolved depth range. The Southwest Rift Zone and the East Rift Zone exhibit very high Qp values at about 9 km depth, whereas the shallow depths are characterized with low-Qp anomalies comparable with those in the summit area. The seismic zones and fault systems generally display relatively high Qp values relative to the summit. The newly developed Qp model provides an important complement to the existing velocity models for exploring the magmatic system and evaluating and interpreting intrinsic physical properties of the rocks in the study area.
- Published
- 2015
77. Seismic velocity structure and earthquake relocation for the magmatic system beneath Long Valley Caldera, eastern California
- Author
-
Guoqing Lin
- Subjects
Earthquake catalog ,Geophysics ,Geochemistry and Petrology ,Seismic velocity ,Resurgent dome ,Magma ,Geodetic datum ,Caldera ,Magma chamber ,Induced seismicity ,Seismology ,Geology - Abstract
A new three-dimensional (3-D) seismic velocity model and high-precision location catalog for earthquakes between 1984 and 2014 are presented for Long Valley Caldera and its adjacent fault zones in eastern California. The simul2000 tomography algorithm is applied to derive the 3-D Vp and Vp/Vs models using first-arrivals of 1004 composite earthquakes obtained from the original seismic data at the Northern California Earthquake Data Center. The resulting Vp model reflects geological structures and agrees with previous local tomographic studies. The simultaneously resolved Vp/Vs model is a major contribution of this study providing an important complement to the Vp model for the interpretation of structural heterogeneities and physical properties in the study area. The caldera is dominated by low Vp anomalies at shallow depths due to postcaldera fill. High Vp and low Vp/Vs values are resolved from the surface to ~ 3.4 km depth beneath the center of the caldera, corresponding to the structural uplift of the Resurgent Dome. An aseismic body with low Vp and high Vp/Vs anomalies at 4.2–6.2 km depth below the surface is consistent with the location of partial melt suggested by previous studies based on Vp models only and the inflation source locations based on geodetic modeling. The Sierran crystalline rocks outside the caldera are generally characterized with high Vp and low Vp/Vs values. The newly resolved velocity model improves absolute location accuracy for the seismicity in the study area and ultimately provides the basis for a high-precision earthquake catalog based on similar-event cluster analysis and waveform cross-correlation data. The fine-scale velocity structure and precise earthquake relocations are useful for investigating magma sources, seismicity and stress interaction and other seismological studies in Long Valley.
- Published
- 2015
78. Integration challenges of low temperature BEOL interconnects
- Author
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Yew Tuck Chow, Yi Wanbing, Chin Chuan Neo, Francis Poh, Sarin A. Deshpande, Yi Jiang, Bharat Bhushan, Juan Boon Tan, Kah Wee, Kerry Joseph Nagel, Sanjeev Aggarwal, Moazzem Hossain, Wang Zhehui, Ju Dy, Danny Pak-Chum Shum, and Guoqing Lin
- Subjects
Stress (mechanics) ,Reliability (semiconductor) ,Materials science ,Passivation ,CMOS ,business.industry ,Stress migration ,Electronic engineering ,Copper interconnect ,Optoelectronics ,Undercut ,Photoresist ,business - Abstract
We present the first exploratory low temperature, lower than standard back-end-of-line (BEOL) interconnects temperature in CMOS. The approach poses several challenges such as undercut in pad via, photo resist residue defects post Aluminum (Al) etch and patch defects post passivation etch. We achieved the electrical targets and met reliability specifications of passivation integrity test (PIT), stress migration (SM), electro migration (EM) for high aspect ratio (HAR) dual damascene via, and pad via interconnects.
- Published
- 2017
79. Three-Dimensional Compressional Attenuation Model (QP) for the Salton Trough, Southern California
- Author
-
Guoqing Lin
- Subjects
Geophysics ,Amplitude ,Geochemistry and Petrology ,Attenuation ,Trough (geology) ,Range (statistics) ,Mineralogy ,Sedimentary rock ,Crust ,Active fault ,Spectral line ,Geology - Abstract
I present a frequency‐independent 3D seismic attenuation model (indicated by ) for the crust of the Salton trough and the adjacent regions in southeastern southern California. The simul2000 tomographic algorithm was used to invert the frequency‐independent attenuation operator t * values measured from amplitude spectra of 23,378 P ‐wave arrivals of 1203 events through a recently developed 3D velocity model. The Q P model has a uniform horizontal grid spacing of 5 km, and the vertical‐node intervals range between 2 and 5 km down to 27 km depth. In general, the Q P values increase with depth and agree with the surface geology in the shallow depth layers. Low Q P values are observed in the Imperial Valley, California, which are consistent with the sedimentary deposits and may also reflect the presence of pore fluid in the active fault zones, whereas greatly elevated Q P values are shown in the surrounding crystalline ranges. The new Q P model provides an important complement to the existing velocity models for interpreting structural heterogeneity and fluid saturation of rocks in the study area. Online Material: Figures of checkerboard resolution tests, Q P versus V P , and Q P versus heat flow.
- Published
- 2014
80. Three-dimensional Vp and Vp/Vs models in the Coso geothermal area, California: Seismic characterization of the magmatic system
- Author
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Guoqing Lin and Qiong Zhang
- Subjects
geography ,geography.geographical_feature_category ,Felsic ,Sediment ,Induced seismicity ,High silica ,Geophysics ,Volcano ,Space and Planetary Science ,Geochemistry and Petrology ,Seismic tomography ,Earth and Planetary Sciences (miscellaneous) ,Geothermal gradient ,Geology ,Seismology ,Waveform cross correlation - Abstract
We combine classic and state-of-the-art techniques to characterize the seismic and volcanic features in the Coso area in southern California. Seismic tomography inversions are carried out to map the variations of Vp, Vs, and Vp/Vs beneath Coso. The velocities in the top layers of our model are correlated with the surface geological features. The Indian Wells Valley, with high silica content sediment strata, shows low-velocity anomalies up to 3 km depth, whereas the major mountain ranges, such as the south Sierra Nevada and the Argus Range, show higher velocities. The resulting three-dimensional velocity model is used to improve absolute locations for all local events between January 1981 and August 2011 in our study area. We then apply similar-event cluster analysis, waveform cross correlation, and differential time relocation methods to improve relative event location accuracy. A dramatic sharpening of seismicity patterns is obtained after using these methods. We also estimate high-resolution near-source Vp/Vs ratio within each event cluster using the differential times from waveform cross correlation. The in situ Vp/Vs method confirms the trend of the velocity variations from the tomographic results. An anomalous low-velocity body with low Vp, Vs, and Vp/Vs ratios, corresponding to the ductile behavior underlying the Coso geothermal field from 6 to 12 km depth, can be explained by the existence of frozen felsic magmatic materials with the inclusion of water. The material is not likely to include pervasive partial melt due to a lack of high Vp/Vs ratios.
- Published
- 2014
81. Three-dimensional seismic velocity structure of Mauna Loa and Kilauea volcanoes in Hawaii from local seismic tomography
- Author
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Guoqing Lin, Peter M. Shearer, Falk Amelung, Paul G. Okubo, and Robin S. Matoza
- Subjects
Shear waves ,geography ,geography.geographical_feature_category ,Gabbro ,Fault (geology) ,Geophysics ,Volcano ,Space and Planetary Science ,Geochemistry and Petrology ,Seismic tomography ,Earth and Planetary Sciences (miscellaneous) ,Caldera ,Mafic ,Rift zone ,Geology ,Seismology - Abstract
We present a new three-dimensional seismic velocity model of the crustal and upper mantle structure for Mauna Loa and Kilauea volcanoes in Hawaii. Our model is derived from the first-arrival times of the compressional and shear waves from about 53,000 events on and near the Island of Hawaii between 1992 and 2009 recorded by the Hawaiian Volcano Observatory stations. The Vp model generally agrees with previous studies, showing high-velocity anomalies near the calderas and rift zones and low-velocity anomalies in the fault systems. The most significant difference from previous models is in V p/Vs structure. The high-Vp and high-V p/Vs anomalies below Mauna Loa caldera are interpreted as mafic magmatic cumulates. The observed low-Vp and high-V p/Vs bodies in the Kaoiki seismic zone between 5 and 15 km depth are attributed to the underlying volcaniclastic sediments. The high-Vp and moderate- to low-Vp/Vs anomalies beneath Kilauea caldera can be explained by a combination of different mafic compositions, likely to be olivine-rich gabbro and dunite. The systematically low-Vp and low-Vp/Vs bodies in the southeast flank of Kilauea may be caused by the presence of volatiles. Another difference between this study and previous ones is the improved Vp model resolution in deeper layers, owing to the inclusion of events with large epicentral distances. The new velocity model is used to relocate the seismicity of Mauna Loa and Kilauea for improved absolute locations and ultimately to develop a high-precision earthquake catalog using waveform cross-correlation data. ©2014. American Geophysical Union. All Rights Reserved.
- Published
- 2014
82. Three‐dimensional compressional wave attenuation tomography for the crust and uppermost mantle of Northern and central California
- Author
-
Guoqing Lin
- Subjects
geography ,geography.geographical_feature_category ,Attenuation ,P wave ,Inversion (geology) ,Crust ,Fault (geology) ,Mantle (geology) ,Geophysics ,Amplitude ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Geology ,Seismology ,Longitudinal wave - Abstract
I present a frequency-independent three-dimensional (3-D) compressional wave attenuation model (indicated by quality factor Qp) for the crust and uppermost mantle of Northern and central California. The tomographic inversion used t∗ values measured from amplitude spectra of 80,988 P wave arrivals of 3247 events recorded by 463 network stations through a 3-D seismic velocity model. The model has a uniform horizontal grid spacing of 15 km, and the vertical node intervals range between 2 and 10 km down to 45 km depth. In general, the resulting Qp values increase with depth and agree with the surface geology at shallow depth layers. The most significant features observed in the Qp model are the high Qp values in the Sierra Nevada mountains and low Qp anomalies in the western fault zones. Low Qp values are also imaged in Owens Valley and Long Valley at shallow depths and the Cape Mendocino region in the lower crust (∼25 km depth). An overall contrast of Qp values across the fault is observed in the creeping, Parkfield and Cholame-Carrizo sections of the San Andreas Fault. The new 3-D Qp model provides an important complement to the existing regional-scale velocity models for interpreting structural heterogeneity and fluid saturation of rocks in the study area.
- Published
- 2014
83. Adaptive ambient noise tomography and its application to the Garlock Fault, southern California
- Author
-
Peng Li and Guoqing Lin
- Subjects
geography ,Geophysics ,geography.geographical_feature_category ,Geochemistry and Petrology ,Seismic tomography ,Ambient noise level ,Inverse theory ,Tomography ,Fault (geology) ,Geology ,Seismology ,Computational seismology - Published
- 2014
84. Seismic evidence for a crustal magma reservoir beneath the upper east rift zone of Kilauea volcano, Hawaii
- Author
-
Paul G. Okubo, Falk Amelung, Guoqing Lin, and Yan Lavallée
- Subjects
geography ,geography.geographical_feature_category ,Volcano ,Shear (geology) ,Seismic velocity ,Rapid expansion ,Petrophysics ,Wave velocity ,Compressional wave velocity ,Geology ,Rift zone ,Seismology - Abstract
An anomalous body with low Vp (compressional wave velocity), low Vs (shear wave velocity), and high Vp/Vs anomalies is observed at 8–11 km depth beneath the upper east rift zone of Kilauea volcano in Hawaii by simultaneous inversion of seismic velocity structure and earthquake locations. We interpret this body to be a crustal magma reservoir beneath the volcanic pile, similar to those widely recognized beneath mid-ocean ridge volcanoes. Combined seismic velocity and petrophysical models suggest the presence of 10% melt in a cumulate magma mush. This reservoir could have supplied the magma that intruded into the deep section of the east rift zone and caused its rapid expansion following the 1975 M7.2 Kalapana earthquake.
- Published
- 2014
85. Transport of green synthetic iron nanoparticles in porous media: effect of injecting concentration and flow velocity
- Author
-
LiZhi Yang, XinYu Yan, GuoQing Lin, and HengHua Zhu
- Subjects
Materials science ,Chemical engineering ,Flow velocity ,Nanoparticle ,Porous medium - Published
- 2018
86. Three-Dimensional Seismic Velocity Structure and Precise Earthquake Relocations in the Salton Trough, Southern California
- Author
-
Guoqing Lin
- Subjects
geography ,geography.geographical_feature_category ,Trough (geology) ,Crust ,Induced seismicity ,Fault (geology) ,Detachment fault ,Model resolution ,Geophysics ,Geochemistry and Petrology ,Seismic velocity ,Refraction (sound) ,Geology ,Seismology - Abstract
I present a new 3D seismic velocity model and high‐precision earthquake relocations between 1981 and 2010 near the Salton Trough and the San Jacinto fault zone. The simul2000 tomography algorithm is applied to derive the 3D V P and V P / V S models using first arrivals of a composite event data set. The final V P model correlates with geological features at shallow depths and is more consistent with the refraction studies than the starting 3D regional‐scale model. The V P / V S model shows strong variations in the upper crust and is dominated by relatively low values (below 1.7) in the middle crust except for the Salton Trough and the Imperial Valley. The newly resolved model is used to relocate all the seismicity in the study area. I then apply the similar‐event cluster analysis and differential‐time relocation approach based on waveform cross‐correlation data to the 3D relocated events. A dramatic sharpening of seismicity patterns is obtained after using these methods. The new locations are more tightly clustered than the previous catalogs mainly due to the different absolute locations. The depth distribution along a basal surface may suggest the existence of a detachment fault from the north end of the Salton Trough to United States–Mexico border. The fine‐scale velocity structure and precise earthquake relocations will be helpful for investigating the fault geometry, seismicity, stress interaction, and other seismological studies for southern California. Online Material: Figures of model resolution tests, cross‐sectional comparisons of different P ‐velocity models, and earthquake depth distributions.
- Published
- 2013
87. Alleviation of cadmium toxicity in Medicago sativa by hydrogen-rich water
- Author
-
Wenbiao Shen, Weiti Cui, Cunyi Gao, Guoqing Lin, and Peng Fang
- Subjects
Time Factors ,Environmental Engineering ,Antioxidant ,Thiobarbituric acid ,Health, Toxicology and Mutagenesis ,medicine.medical_treatment ,medicine.disease_cause ,Plant Roots ,Thiobarbituric Acid Reactive Substances ,Antioxidants ,Lipid peroxidation ,chemistry.chemical_compound ,Paraquat ,medicine ,TBARS ,Homeostasis ,Environmental Chemistry ,Waste Management and Disposal ,chemistry.chemical_classification ,Reactive oxygen species ,Water ,DNA ,Glutathione ,Pollution ,Oxidative Stress ,chemistry ,Biochemistry ,Seedlings ,Gases ,Lipid Peroxidation ,Reactive Oxygen Species ,Oxidation-Reduction ,Oxidative stress ,Cadmium ,Hydrogen ,Medicago sativa - Abstract
Hydrogen gas (H₂) induces plant tolerance to several abiotic stresses, including salinity and paraquat exposure. However, the role of H₂ in cadmium (Cd)-induced stress amelioration is largely unknown. Here, pretreatment with hydrogen-rich water (HRW) was used to characterize physiological roles and molecular mechanisms of H₂ in the alleviation of Cd toxicity in alfalfa plants. Our results showed that the addition of HRW at 10% saturation significantly decreased contents of thiobarbituric acid reactive substances (TBARS) caused by Cd, and inhibited the appearance of Cd toxicity symptoms, including the improvement of root elongation and seedling growth. These responses were related to a significant increase in the total or isozymatic activities of representative antioxidant enzymes, or their corresponding transcripts. In vivo imaging of reactive oxygen species (ROS), and the detection of lipid peroxidation and the loss of plasma membrane integrity provided further evidence for the ability of HRW to improve Cd tolerance significantly, which was consistent with a significant enhancement of the ratio of reduced/oxidized (homo)glutathione ((h)GSH). Additionally, plants pretreated with HRW accumulated less amounts of Cd. Together, this study suggested that the usage of HRW could be an effective approach for Cd detoxification and could be explored in agricultural production systems.
- Published
- 2013
88. Seismic investigation of magmatic unrest beneath Mammoth Mountain, California, USA
- Author
-
Guoqing Lin
- Subjects
Basalt ,Intrusion ,biology ,Magma ,Geology ,Induced seismicity ,Unrest ,biology.organism_classification ,Seismology ,Sea level ,Mammoth ,Earthquake location - Abstract
I present a reinvestigation of the seismic activity during an 11-mo-long seismic swarm between 1989 and 1990 beneath Mammoth Mountain in eastern California (United States). This swarm, believed to be the result of a shallow intrusion of magma beneath Mammoth Mountain, was followed by the emission of magmatic CO 2 gas, resulting in tree die-off in 1990 and posing a signifi cant human health risk around Mammoth Mountain. In this study, I apply a state-of-the-art approach to estimate the ratio of compressional- to shear-wave velocity (Vp/Vs) within similar event clusters using differential times from waveform crosscorrelation. A high-resolution three-dimensional seismic velocity model and a precise earthquake location catalog are obtained to complement the analysis of the in situ Vp/Vs ratios. The majority of the relocated seismicity below sea level is distributed in an anomalous body with low Vp and high Vp/Vs, consistent with the seismic expression of the magma body that triggered the seismic swarm. Abrupt changes in Vp/Vs ratios, with lower values for the shallow depths, are observed near sea level, indicating the source of the 1989 CO 2 fl ux is a shallow CO 2 reservoir instead of the hypothesized basaltic magma at mid-crustal depths of 10-25 km. From sea level to the surface, low Vp/Vs ratios in a near-vertical zone suggest involvement of fl uid in the upward-migration of the seismicity.
- Published
- 2013
89. Flood Routing Simulation and System Customization for a High-Leakage River Channel in China
- Author
-
Shoubo Tian, Shuai Song, Fadong Li, Xilai Zheng, and Guoqing Lin
- Subjects
Hydrology ,Infiltration (hydrology) ,Flood myth ,Mathematical model ,Approximation error ,Mechanical Engineering ,Environmental science ,Surface finish ,Leakage (economics) ,Groundwater ,Water Science and Technology ,Civil and Structural Engineering ,Water level - Abstract
Leakage is a major factor impacting the evolution of flood in a highly permeable river. By integrating a mathematical model with data provided by a monitoring database, a flood routing system was developed for the Dagu River in China. The aim of this study was to calculate the leakage discharge and to discuss the effect of leakage for flood modeling within a high-leakage riverbed. This system was implemented for application of a flood-diversion experiment in 2003, which accessed data automatically and used estimated coefficients to calculate leakage discharge. The results showed that simulated discharge values fit well with the measured values, with an average relative error less than 10%, and the leakage average relative error was approximately 2%. The infiltration experiments showed that the leakage coefficient could be treated as a constant when the dynamics in the initial phase of a short flood event was stimulated. The initial water level and leakage and roughness coefficients were the main factors required to accurately determine the discharge of river seepage. DOI: 10.1061/(ASCE)HY.1943-7900.0000710. © 2013 American Society of Civil Engineers. CE Database subject headings: Flood routing; River beds; Leakage; Coefficients; Roughness; Coefficients; China; Simulation. Author keywords: Flood routing; Riverbed leakage; Leakage coefficient; Roughness coefficient.
- Published
- 2013
90. Systematic relocation of seismicity on Hawaii Island from 1992 to 2009 using waveform cross correlation and cluster analysis
- Author
-
Robin S. Matoza, Peter M. Shearer, Paul G. Okubo, Cecily J. Wolfe, and Guoqing Lin
- Subjects
geography ,geography.geographical_feature_category ,Marine geology ,Induced seismicity ,Fault (geology) ,Tectonics ,Geophysics ,Volcano ,Space and Planetary Science ,Geochemistry and Petrology ,Observatory ,Earth and Planetary Sciences (miscellaneous) ,Geological survey ,Rift zone ,Seismology ,Geology - Abstract
JOURNAL OF GEOPHYSICAL RESEARCH: SOLID EARTH, VOL. 118, 2275–2288, doi:10.1002/jgrb.50189, 2013 Systematic relocation of seismicity on Hawaii Island from 1992 to 2009 using waveform cross correlation and cluster analysis Robin S. Matoza, 1 Peter M. Shearer, 1 Guoqing Lin, 2 Cecily J. Wolfe, 3,4 and Paul G. Okubo 5 Received 28 November 2012; revised 8 April 2013; accepted 10 April 2013; published 20 May 2013. [ 1 ] The analysis and interpretation of seismicity from mantle depths to the surface play a key role in understanding how Hawaiian volcanoes work. We present results from a comprehensive and systematic re-analysis of waveforms from 130,902 seismic events recorded by the U.S. Geological Survey Hawaiian Volcano Observatory permanent seismic network from January 1992 to March 2009. We compute high-precision relative relocations for 101,390 events (77% of all events considered) using waveform cross correlation and cluster analysis, resulting in a multiyear systematically processed catalog of seismicity for all of Hawaii Island. The 17 years of relocated seismicity exhibit a dramatic sharpening of earthquake clustering along faults, streaks, and magmatic features, permitting a more detailed understanding of fault geometries and volcanic and tectonic processes. Our relocation results are generally consistent with previous studies that have focused on more specific regions of Hawaii. The relocated catalog includes crustal seismicity at Kilauea and its rift zones, seismicity delineating crustal detachment faults separating volcanic pile and old oceanic crust on the flanks of Kilauea and Mauna Loa, events along inferred magma conduits, and events along inferred mantle fault zones. The relocated catalog is available for download in the supporting information. Citation: Matoza, R. S., P. M. Shearer, G. Lin, C. J. Wolfe, and P. G. Okubo (2013), Systematic relocation of seismicity on Hawaii Island from 1992 to 2009 using waveform cross correlation and cluster analysis, J. Geophys. Res. Solid Earth, 118, 2275–2288, doi:10.1002/jgrb.50189. 1. Introduction [ 2 ] Seismic investigations began on Hawaii Island (Figure 1a) over 100 years ago [Jaggar, 1920], and a teleme- tered electronic seismic network was first installed in the late 1950s and has been steadily growing and improving ever since [Eaton and Murata, 1960; Klein and Koyanagi, 1980; Klein et al., 1987; Kauahikaua and Poland, 2012]. Additional supporting information may be found in the online version of this article. Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA. Division of Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA. Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, Hawaii, USA. Now at Earthquake Hazards Program, U.S. Geological Survey, Reston, Virginia, USA. Hawaiian Volcano Observatory, U.S. Geological Survey, Hawaii Volcanoes National Park, Hawaii, USA. Corresponding author: R. S. Matoza, Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0225, USA. (rmatoza@ucsd.edu) ©2013. American Geophysical Union. All Rights Reserved. 2169-9313/13/10.1002/jgrb.50189 The current network operated by the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) (Figure 1a) records approximately 5000–10,000 seismic events per year [Nakata, 2007; Nakata and Okubo, 2010]. Seismicity has played a central role in developing models of how Hawaiian volcanoes work [e.g., Eaton and Murata, 1960; Eaton, 1962; Klein et al., 1987; Ryan, 1988; Tilling and Dvorak, 1993; Wright and Klein, 2006; Got et al., 2008]. [ 3 ] Significant improvements in the relative loca- tion accuracy among nearby seismic events can be achieved without solving directly for the biasing effects of three-dimensional (3-D) velocity heterogeneity [e.g., Douglas, 1967; Frohlich, 1979; Frechet, 1985; Got et al., 1994; Shearer, 1997; Richards-Dinger and Shearer, 2000; Waldhauser and Ellsworth, 2000; Lin and Shearer, 2005]. Relative relocation can achieve high location precision using differential times obtained via waveform cross correla- tion [e.g., Frechet, 1985; Got et al., 1994; Fremont and Malone, 1987; Nadeau et al., 1995; Waldhauser et al., 1999; Shearer et al., 2005; Lin et al., 2007], in many cases collaps- ing diffuse seismicity to compact streaks aligned with fault slip [Rubin et al., 1999] or to planar surfaces reflecting fault planes [Got et al., 1994]. Relative relocation techniques have been used extensively to study seismicity on Hawaii Island; however, most studies have focused on subregions of the island or specific event sequences or types [e.g., Got et al., 1994; Gillard et al., 1996; Got and Okubo, 2003; Battaglia
- Published
- 2013
91. JPSS-1 VIIRS at-launch geometric performance
- Author
-
Robert E. Wolfe and Guoqing Lin
- Subjects
Visible Infrared Imaging Radiometer Suite ,010504 meteorology & atmospheric sciences ,Spacecraft ,business.industry ,Detector ,Spectral bands ,Orbital mechanics ,01 natural sciences ,010309 optics ,Optics ,Optical transfer function ,0103 physical sciences ,Environmental science ,Satellite ,business ,Image resolution ,0105 earth and related environmental sciences ,Remote sensing - Abstract
Following the successful operations of the first Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on-board the Suomi National Polar‐orbiting Partnership (SNPP) spacecraft since launch in October 2011, a second VIIRS instrument to be on-board the first Joint Polar Satellite System (JPSS-1) satellite has been fabricated, tested and integrated onto the spacecraft, readying for launch in 2017. The ground testing, including geometric functional performance testing and characterization, at the sensor level was completed in December 2014. Testing at the spacecraft level is on-going. The instrument geometric performance includes sensor (detector) spatial response, band-to-band coregistration (BBR), scan plane and pointing stability. The parameters have been calibrated and characterized through ground testing under ambient and thermal vacuum conditions, and numerical modeling and analysis. VIIRS sensor spatial response is measured by line spread functions (LSFs) in the scan and track directions for every detector. We parameterize the LSFs by: 1) dynamic field of view (DFOV) in the scan direction and instantaneous FOV (IFOV) in the track direction; and 2) modulation transfer function (MTF) for the 17 moderate resolution bands (M-bands) and for the five imagery bands (I-bands). We define VIIRS BBR for M-bands and I-bands as the overlapped fractional area of angular pixel sizes from the corresponding detectors in a band pair, including nested I-bands within the M-bands. The ground tests result in static BBR matrices. VIIRS pointing measurements include scan plane tilt and instrument-to-spacecraft mounting coefficients. This paper summarizes the pre-launch test results along with anomaly investigations. The pre-launch performance parameters will be tracked or corrected for as needed in on-orbit operations.
- Published
- 2016
92. Assessing effects of soil hydraulic properties on the temporal stability of absolute soil moisture content and soil moisture anomaly under different climatic conditions
- Author
-
Xilai Zheng, Tiejun Wang, and Guoqing Lin
- Subjects
Global and Planetary Change ,010504 meteorology & atmospheric sciences ,Moisture ,0208 environmental biotechnology ,Soil Science ,Geology ,Soil science ,02 engineering and technology ,01 natural sciences ,Pollution ,Spearman's rank correlation coefficient ,020801 environmental engineering ,Infiltration (hydrology) ,Hydraulic conductivity ,Pedotransfer function ,Soil water ,Vadose zone ,Environmental Chemistry ,Environmental science ,Water content ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology - Abstract
Due to the complex interactions of soil moisture with its controlling factors, numerical models are more suitable for quantifying different controls on the temporal pattern of soil moisture. Here, the effects of soil hydraulic properties on the temporal stability of absolute soil moisture content (TS SMC) and soil moisture anomaly (TS SMA) under different climatic conditions were assessed using a vadose zone model. To run the model, two soil datasets with van Genuchten parameters were generated and hydrometeorological data from four study sites with a significant precipitation gradient were obtained. The TS SMC analysis revealed that the patterns of mean relative difference (MRD) and standard deviation of relative difference (SDRD) of soil moisture partly depended on climatic conditions. With increasing precipitation, the range of MRD generally decreased; whereas, the range and mean value of SDRD increased, indicating that soil moisture was temporally more stable under drier climatic conditions. Based on the Spearman rank correlation coefficient, the results showed that the dependence of MRD on soil hydraulic parameters was partly determined by climatic conditions. With decreasing precipitation, the effects of residual soil moisture content, saturated hydraulic conductivity, and the parameter l that accounts for pore tortuosity and connectivity strengthened, while the effects of saturated soil moisture content and the parameter n that is a measure of pore size distribution weakened. Finally, according to the Pearson correlation coefficient, the results revealed that the control of soil hydraulic properties was shown to be reduced in the TS SMA analysis, thus confirming the previously made conjecture that the use of soil moisture anomalies in the temporal stability analysis reduces the impacts of static soil properties.
- Published
- 2016
93. Identification of a tetratricopeptide repeat-like domain in the nicastrin subunit of γ-secretase using synthetic antibodies
- Author
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Georgia Dolios, Marcin Paduch, Kwangwook Ahn, Yue-Ming Li, Rong Wang, Akiko Koide, Robert J. Hoey, Shohei Koide, Xulun Zhang, Takeshi Ikeuchi, Sangram S. Sisodia, Brenda Leung, and Guoqing Lin
- Subjects
Repetitive Sequences, Amino Acid ,Protein Conformation ,Blotting, Western ,Nicastrin ,Plasma protein binding ,Antibodies ,Amyloid beta-Protein Precursor ,Epitopes ,Mice ,Protein structure ,Tandem Mass Spectrometry ,Amyloid precursor protein ,Animals ,Humans ,Amino Acid Sequence ,APH-1 ,Cells, Cultured ,Mice, Knockout ,Binding Sites ,Membrane Glycoproteins ,Multidisciplinary ,biology ,Circular Dichroism ,Biological Sciences ,Surface Plasmon Resonance ,Immunohistochemistry ,Protein Structure, Tertiary ,Cell biology ,Synthetic antibody ,Tetratricopeptide ,HEK293 Cells ,Ectodomain ,Biochemistry ,Mutation ,Biocatalysis ,biology.protein ,Amyloid Precursor Protein Secretases ,Oligopeptides ,Protein Binding - Abstract
The γ-secretase complex, composed of presenilin, anterior-pharynx-defective 1, nicastrin, and presenilin enhancer 2, catalyzes the intramembranous processing of a wide variety of type I membrane proteins, including amyloid precursor protein (APP) and Notch. Earlier studies have revealed that nicastrin, a type I membrane-anchored glycoprotein, plays a role in γ-secretase assembly and trafficking and has been proposed to bind substrates. To gain more insights regarding nicastrin structure and function, we generated a conformation-specific synthetic antibody and used it as a molecular probe to map functional domains within nicastrin ectodomain. The antibody bound to a conformational epitope within a nicastrin segment encompassing residues 245–630 and inhibited the processing of APP and Notch substrates in in vitro γ-secretase activity assays, suggesting that a functional domain pertinent to γ-secretase activity resides within this region. Epitope mapping and database searches revealed the presence of a structured segment, located downstream of the previously identified DAP domain ( D YIGS a nd p eptidase; residues 261–502), that is homologous to a tetratricopeptide repeat (TPR) domain commonly involved in peptide recognition. Mutagenesis analyses within the predicted TPR-like domain showed that disruption of the signature helical structure resulted in the loss of γ-secretase activity but not the assembly of the γ-secretase and that Leu571 within the TPR-like domain plays an important role in mediating substrate binding. Taken together, these studies offer provocative insights pertaining to the structural basis for nicastrin function as a “substrate receptor” within the γ-secretase complex.
- Published
- 2012
94. Paenibacillus terreus sp. nov., isolated from forest soil
- Author
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Guoqing Lin, Guo Xiang Wang, Wenjuan Dai, Zhi Huang, Zhijun Zhou, Fei Zhao, and Xixue Yan
- Subjects
0106 biological sciences ,0301 basic medicine ,DNA, Bacterial ,China ,Molecular Sequence Data ,Peptidoglycan ,Forests ,Diaminopimelic Acid ,010603 evolutionary biology ,01 natural sciences ,Microbiology ,03 medical and health sciences ,Paenibacillus ,chemistry.chemical_compound ,RNA, Ribosomal, 16S ,Botany ,Ecology, Evolution, Behavior and Systematics ,Phospholipids ,Phylogeny ,Soil Microbiology ,Base Composition ,biology ,Strain (chemistry) ,Fatty Acids ,Nucleic Acid Hybridization ,Vitamin K 2 ,General Medicine ,Sequence Analysis, DNA ,Ribosomal RNA ,biology.organism_classification ,16S ribosomal RNA ,Bacterial Typing Techniques ,030104 developmental biology ,chemistry ,Diaminopimelic acid ,Soil microbiology ,Bacteria - Abstract
A Gram-stain-positive, rod-shaped, endospore-forming, motile bacterium, designated D33T, was isolated from a forest soil sample. The strain grew optimally at 30-37 °C, pH 8.0 and with 1 % (w/v) NaCl. The 16S rRNA gene sequence of the isolate showed similarities lower than 97 % with respect to species of the genus Paenibacillus. Strain D33T contained meso-diaminopimelic acid in the cell-wall peptidoglycan, and ribose and lower amounts of glucose and galactose as the whole-cell sugars. The major cellular fatty acid was anteiso-C15 : 0, and menaquinone-7 (MK-7) was the only respiratory quinone. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmethylethanolamine, two glycolipids and an unknown lipid. The DNA G+C content was 51.1 mol%. The low DNA-DNA relatedness values between strain D33T and recognized species of the genus Paenibacillus, together with many phenotypic properties supported the classification of strain D33T as representative of a novel species of the genus Paenibacillus, for which the name Paenibacillus terreus sp. nov. is proposed. The type strain is D33T ( = KACC 18491T = DSM 100035T = CCTCC AB 2015273T).
- Published
- 2015
95. A California Statewide Three-Dimensional Seismic Velocity Model from Both Absolute and Differential Times
- Author
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Egill Hauksson, Felix Waldhauser, Peter M. Shearer, Jeanne L. Hardebeck, Clifford H. Thurber, Haijiang Zhang, Thomas M. Brocher, and Guoqing Lin
- Subjects
USArray ,Wave model ,Geophysics ,Geochemistry and Petrology ,Seismic velocity ,Waveform ,Crust ,Geology ,Mantle (geology) ,Seismology ,Earthquake location - Abstract
We obtain a seismic velocity model of the California crust and uppermost mantle using a regional-scale double-difference tomography algorithm. We begin by using absolute arrival-time picks to solve for a coarse three-dimensional (3D) P velocity ( V P ) model with a uniform 30 km horizontal node spacing, which we then use as the starting model for a finer-scale inversion using double-difference tomography applied to absolute and differential pick times. For computational reasons, we split the state into 5 subregions with a grid spacing of 10 to 20 km and assemble our final statewide V P model by stitching together these local models. We also solve for a statewide S -wave model using S picks from both the Southern California Seismic Network and USArray, assuming a starting model based on the V P results and a V P / V S ratio of 1.732. Our new model has improved areal coverage compared with previous models, extending 570 km in the SW–NE direction and 1320 km in the NW–SE direction. It also extends to greater depth due to the inclusion of substantial data at large epicentral distances. Our V P model generally agrees with previous separate regional models for northern and southern California, but we also observe some new features, such as high-velocity anomalies at shallow depths in the Klamath Mountains and Mount Shasta area, somewhat slow velocities in the northern Coast Ranges, and slow anomalies beneath the Sierra Nevada at midcrustal and greater depths. This model can be applied to a variety of regional-scale studies in California, such as developing a unified statewide earthquake location catalog and performing regional waveform modeling.
- Published
- 2010
96. A Search for Temporal Variations in Station Terms in Southern California from 1984 to 2002
- Author
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Guoqing Lin, Peter M. Shearer, and Egill Hauksson
- Subjects
Geophysics ,Shock (fluid dynamics) ,Meteorology ,Geochemistry and Petrology ,Geodesy ,Caltech Library Services ,Apparent velocity ,Geology ,Event (probability theory) - Abstract
We use relative arrival times and locations for similar earthquake pairs that are found using a cross-correlation method to analyze the time dependence of P and S station terms in southern California from 1984 to 2002. We examine 494 similar event clusters recorded by Southern California Seismic Network (SCSN) stations and compute absolute arrival-time variations from the differential arrival-time resi- duals obtained following event relocation. We compute station terms from the robust means of the absolute arrival-time residuals from all events recorded by each station at 3-month intervals. We observe nine stations with abrupt offsets in timing of 20- 70 msec, which are likely caused by equipment changes during our study period. Taking these changes into account could improve the relative location accuracy for some of the event clusters. For other stations, we generally do not see systematic temporal variations greater than about 10 msec. Analysis of residuals along individual ray paths does not reveal any clear localized regions of apparent velocity changes at depth. These results limit large-scale, long-lasting temporal variations in P and S ve- locities across southern California during this time period to less than about � 0:2%. However, there is an increased fraction of individual travel-time residuals exceeding 20 msec immediately following major earthquakes from source regions near the main- shock rupture.
- Published
- 2008
97. The first antimicrobial peptide from sea amphibian
- Author
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Yufang Ma, Yi Lu, Xu Wang, Jianguo Liang, Keyun Zhang, Chongxin Zhang, Guoqing Lin, and Ren Lai
- Subjects
Signal peptide ,Amphibian ,DNA, Complementary ,animal structures ,Ranidae ,Oceans and Seas ,Molecular Sequence Data ,Immunology ,Antimicrobial peptides ,Peptide ,Biology ,Amphibian Proteins ,Anti-Infective Agents ,biology.animal ,Complementary DNA ,Animals ,Amino Acid Sequence ,Cloning, Molecular ,Molecular Biology ,Peptide sequence ,Skin ,chemistry.chemical_classification ,Ecology ,cDNA library ,Antimicrobial ,Biochemistry ,chemistry ,Peptides ,Antimicrobial Cationic Peptides - Abstract
The crab-eating frog, Rana cancrivora, is one of only a handful of amphibians worldwide that tolerates saline waters. It typically inhabits brackish water of mangrove forests of Southeast Asia. A large amount of antimicrobial peptides belonging to different families have been identified from skins of amphibians inhabiting freshwater. No antimicrobial peptide from sea amphibians has been reported. In this paper, we firstly reported the antimicrobial peptide and its cDNA cloning from skin secretions of the crab-eating frog R. cancrivora. The antimicrobial peptide was named cancrin with an amino acid sequence of GSAQPYKQLHKVVNWDPYG. By BLAST search, cancrin had no significant similarity to any known peptides. The cDNA encoding cancrin was cloned from the cDNA library of the skin of R. cancrivora. The cancrin precursor is composed of 68 amino acid residues including a signal peptide, acidic spacer peptide, which are similar to other antimicrobial peptide precursors from Ranid amphibians and mature cancrin. The overall structure is similar to other amphibian antimicrobial peptide precursors although mature cancrin is different from known peptides. The current results reported a new family of amphibian antimicrobial peptide and the first antimicrobial peptide from sea amphibian.
- Published
- 2008
98. A bactericidal homodimeric phospholipases A2 from Bungarus fasciatus venom
- Author
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Jianguo Liang, Ren Lai, Chunhua Xu, Yun Zhang, Guoqing Lin, Haining Yu, Dongying Ma, and Zongjie Li
- Subjects
Signal peptide ,Staphylococcus aureus ,Bungarus ,Physiology ,Molecular Sequence Data ,Venom ,Biochemistry ,Phospholipases A ,Microbiology ,Cellular and Molecular Neuroscience ,Endocrinology ,Phospholipase A2 ,Escherichia coli ,Animals ,Amino Acid Sequence ,Protein precursor ,Blood Coagulation ,Peptide sequence ,Chromatography, High Pressure Liquid ,Antibacterial agent ,Elapid Venoms ,Base Sequence ,Dose-Response Relationship, Drug ,Sequence Homology, Amino Acid ,biology ,Group IV Phospholipases A2 ,Anti-Bacterial Agents ,Molecular Weight ,Snake venom ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Chromatography, Gel ,biology.protein ,Electrophoresis, Polyacrylamide Gel ,Dimerization ,Sequence Alignment ,Cysteine - Abstract
Group IIA secretory phospholipases A(2) (sPLA(2)-II) is generally known to display potent gram-positive bactericidal activity, while group IA sPLA(2) (sPLA(2)-I) reportedly is not. In this work, a novel sPLA(2)-I named BFPA was identified from Bungarus fasciatus venom, and its antimicrobial activity was studied as well. The amino acid sequence of the venomous protein precursor was 145-amino acid in length, and contained a predicted 27-amino acid signal peptide and a 118-amino acid mature protein. Unlike the well-known sPLA(2)-Is, which have 14 half-cysteines forming 7 intramolecular disulfide bridges, BFPA possesses 15 half-cysteines. The additional cysteine might contribute to the formation of an intermolecular disulfide bridge of the homodimeric protein. In the biological activities assays, BFPA displayed the activities of anticoagulation and bactericidal against Escherichia coli and Staphylococcus aureus. This study is the first report about gram-positive bactericidal activity of sPLA(2)-I.
- Published
- 2007
99. Estimating Local Vp/Vs Ratios within Similar Earthquake Clusters
- Author
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Peter M. Shearer and Guoqing Lin
- Subjects
Geophysics ,Standard error ,Geochemistry and Petrology ,Statistics ,Inversion methods ,Waveform ,Function method ,Geodesy ,Synthetic data ,Synthetic data sets ,Mathematics ,Event (probability theory) - Abstract
We develop and test a method to estimate local Vp / Vs ratios for compact similar earthquake clusters using the precise P and S differential times obtained using waveform cross-correlation. We demonstrate how our technique works using synthetic data and evaluate likely errors arising from near-source takeoff angle differences between P and S waves. We use a robust misfit function method to compute Vp / Vs ratios for both synthetic data sets and several similar event clusters in southern California, and use a bootstrap resampling approach to estimate standard errors for real data. Our technique has higher resolution for near-source Vp / Vs ratios than typical tomographic inversion methods and provides constraints on near-fault rock properties.
- Published
- 2007
100. Two families of antimicrobial peptides with multiple functions from skin of rufous-spotted torrent frog, Amolops loloensis
- Author
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Haining Yu, Xueqing Xu, Ren Lai, Yi Lu, Jianxu Li, Yongqiang Tian, Dongying Ma, Jianguo Liang, Guoqiang Huang, and Guoqing Lin
- Subjects
Male ,Amphibian ,Ranidae ,Physiology ,Molecular Sequence Data ,Antimicrobial peptides ,Zoology ,Biochemistry ,Cellular and Molecular Neuroscience ,Endocrinology ,Salientia ,biology.animal ,Animals ,Amino Acid Sequence ,Amolops loloensis ,Skin ,Antibacterial agent ,chemistry.chemical_classification ,biology ,Staurois ,biology.organism_classification ,Amino acid ,chemistry ,Multigene Family ,Immunology ,Amolops ,Female ,Antimicrobial Cationic Peptides - Abstract
There are around 27 species of Amolops amphibian distributed in South-east of Asia. Seven antimicrobial peptides (AMPs) belonging to two different families were purified from skin of rufous-spotted torrent frog, Amolops loloensis, and designated brevinins-ALa, b, c, and d, and temporins-ALa, b, and c. The brevinins-AL family which is structurally related to brevinins-1 from skin secretions of the European frog, Rana brevipoda, is composed of 24 amino acids and has an intra-disulfide bridge at the C-terminus. The temporins-AL family, composed of 13 or 16 amino acid residues, is related with temporins from the skin secretions of R. temporaria. The findings of this study will facilitate the solutions to the taxonomic questions of the ranid genus Amolops and Staurois. In the work of this paper, both brevinins-ALb and temporin-Ma induced mast cell degranulation and histamine release, and had cytotoxic activity toward solid tumor cell line HepG2. Brevinins-ALb also exerted strong hemolytic activity while temporin-Ma had no such activity.
- Published
- 2006
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