Engineering topics
Shi, Yan
Publications and source records attributed to Shi, Yan.
Harmonized and high-quality datasets of aerosol optical depth at a US continental site, 1997-2018
Aerosol optical depth (AOD) characterizes the aerosol burden in the atmosphere, while its wavelength dependence is a sign of particle size. Long-term records of wavelength-resolved AOD with high quality and suitable continuity are required for climate change assessment. Typically, climate-related studies use AOD products provided by several, and perhaps different, ground-based instruments. The measurements from these instruments often have different accuracy and temporal resolution. To preserve the advantages of these products (high quality) and to reduce their disadvantages (patchy records), we generate a merged dataset obtained from several instruments in which a nearly-continuous AOD record is found at two wavelengths (500 and 870 nm) with high quality and high temporal resolution (1-min) for a 21-yr period (1997-2018). The combined dataset addresses: (1) varying data quality and resolution mismatch of the individual AOD records, and (2) the uncertainty of the merged AOD and its relevance for user-specified needs. The generated dataset will be beneficial for a wide range of applications including aerosol-radiation interactions and their impact in forcing climate change.
Ice Nucleating Particles (INP) Raw Data
The ice nucleation spectrometer (INS) is an offline analytical measurement system used to process filter samples for freezing temperature spectra of immersion-mode ice-nucleating particle (INP) number concentrations. It is almost identical to the Colorado State University (CSU) ice spectrometer design. Filter samples are collected at ARM facilities routinely and during intensive operational periods, and on the ARM tethered balloon system operated by Sandia National Laboratories, then processed on the INS at CSU. This filter log contains the detailed metadata at all ARM sites where INP filter sample collection has occurred or is currently ongoing. Metadata include start and end times, vacuum line pressures and temperatures, and flow rates; total accumulated flow through each filter; and notes on collection issues or weather conditions. Users can also keep up to date with the status of filter and data processing, even before data are available on ARM's Data Discovery. Users can contact INP mentors Jessie Creamean or Thomas Hill with any questions.
pars2 (b1)
A laser disdrometer (LDIS) measures the drop size spectra and fall velocity of hydrometeors during precipitation events. The passage of hydrometeors through a horizontal area positioned between an eye-safe laser and an array detector results in blockage of the laser beam in proportion to the size of the drop or particle. In addition to drop/particle size and fall speed, precipitation type is classified. ARM also deploys video disdrometers (VDIS).
Evaluation of the Structure and Biological Activities of Condensed Tannins from Acanthus ilicifolius Linn and Their Effect on Fresh-Cut Fuji Apples
Condensed tannins (CT{sub S}) have been isolated and purified from leaves of Acanthus ilicifolius Linn. And their structures were investigated by three methods: {sup 13}C nuclear magnetic resonance ({sup 13}C NMR), reversed-phase high-performance liquid chromatography (RP-HPLC), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The results showed that the CT{sub S} were a mixture of catechin/epicatechin, galatechin/epicatechin, and amphicin/epigalin, and that the polymer chain lengths were 3-mers to 14-mers. Antityrosinase activities and antioxidant activities of the CT{sub S} from A. ilicifolius leaves were further studied. The IC{sub 50} of the CT{sub S} on mushroom tyrosinase activity was determined to be 19.7 ± 0.13 μg/mL, and inhibition type analyses indicated that the CT{sub S} were mixed type inhibitors and their inhibition CT{sub S} was reversible. The CT{sub S} from A. ilicifolius leaves also exhibited potential antioxidant activity. The IC{sub 50} of DPPH and ABTS scavenging activities were 104 ± 0.894 μg/mL and 86 ± 0.616 μg/mL, respectively. And the FRAP value was 758.28 ± 2.42 mg AAE/g. In addition, we found that the CT{sub S} from A. ilicifolius leaves had an excellent effect on preserving the quality of fresh-cut apples by preventing apples from browning through reducing polyphenol oxidase activities in apples.
Long-Term Retrievals of Cloud Type and Fair-Weather Shallow Cumulus Events at the ARM SGP Site
Abstract A long-term climatology of classified cloud types has been generated for 13 years (1997–2009) over the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site for seven cloud categories: low clouds, congestus, deep convection, altocumulus, altostratus, cirrostratus/anvil, and cirrus. The classification was based on the cloud macrophysical quantities of cloud top, cloud base, and physical thickness of cloud layers, as measured by active sensors such as the millimeter-wavelength cloud radar (MMCR) and micropulse lidar (MPL). Climate variability of cloud characteristics has been examined using the 13-yr cloud-type retrieval. Low clouds and cirrus showed distinct diurnal and seasonal cycles. Total cloud occurrence followed the variation of low clouds, with a diurnal peak in early afternoon and a seasonal maximum in late winter. Additionally, further work has been done to identify fair-weather shallow cumulus (FWSC) events for 9 years (2000–08). Periods containing FWSC, a subcategory of clouds classified as low clouds, were produced using cloud fraction information from a total-sky imager and ceilometer. The identified FWSC periods in our study show good agreement with manually identified FWSC, missing only 6 cases out of 70 possible events during the spring to summer seasons (May–August).
ARM Instrument: Eddy Correlation Flux Measurement Smart Flux System (ECORSF)
ARM Instrument: Eddy Correlation Flux Measurement Smart Flux System (ECORSF)
shallowcumulus
shallowcumulus.c1 datastream is generated by shallowcumulus VAP
shcusummary
shcusummary.c1 contains monthly summary files generated by shallowcumulus VAP
Effect of laser mode on microstructure and corrosion resistance of 316L stainless steel weld joint
Not Available
Allele-defined genome of the autopolyploid sugarcane Saccharum spontaneum L.
Modern sugarcanes are polyploid interspecific hybrids, combining high sugar content from Saccharum officinarum with hardiness, disease resistance and ratooning of Saccharum spontaneum. Sequencing of a haploid S. spontaneum, AP85-441, facilitated the assembly of 32 pseudo-chromosomes comprising 8 homologous groups of 4 members each, bearing 35,525 genes with alleles defined. The reduction of basic chromosome number from 10 to 8 in S. spontaneum was caused by fissions of 2 ancestral chromosomes followed by translocations to 4 chromosomes. Surprisingly, 80% of nucleotide binding site-encoding genes associated with disease resistance are located in 4 rearranged chromosomes and 51% of those in rearranged regions. Resequencing of 64 S. spontaneum genomes identified balancing selection in rearranged regions, maintaining their diversity. Introgressed S. spontaneum chromosomes in modern sugarcanes are randomly distributed in AP85-441 genome, indicating random recombination among homologs in different S. spontaneum accessions. The allele-defined Saccharum genome offers new knowledge and resources to accelerate sugarcane improvement.
MicroRNA-128 contributes to the progression of gastric carcinoma through GAREM-mediated MAPK signaling activation
Gastric carcinoma (GC) represents the most common malignant cancer and the second leading cause of cancer death worldwide. However, the molecular mechanisms and biological progression of GC remain unknown. In this study, we found that miR-128 is a critical tumor suppressor that is downregulated in GC patients and GC cells and that GAREM is a direct downstream target of miR-128. Overexpression of miR-128 in HGC-27 and MKN-45 cells resulted in suppressed cell growth and promoted cell apoptosis through a GAREM-dependent mechanism. Moreover, the precise mechanisms underlying the antitumor effect of miR-128 in GC are at least partially due to suppressing activation of the MAPK signaling pathway, induced by suppressing GAREM expression. This study is the first to demonstrate that the miR-128-GAREM-MAPK signaling pathway forms a critical feedback loop and mediates GC development, and these findings might demonstrate a potential therapeutic strategy for GC.