2,054 research outputs found
Quantification of Cloud Condensation Nuclei Effects on the Microphysical Structure of Continental Thunderstorms Using Polarimetric Radar Observations
Aerosols serving as cloud condensation nuclei (CCN) are crucial to the microphysical structure of thunderstorms. They can also alter the rate of cloud microphysical processes, the moisture profile and the local temperature as a result of latent heating/cooling in the early stage of thunderstorm development. Continental thunderstorms are characterized by high complexity and are highly influenced by environmental conditions. The purpose of this study is to determine the influences of CCN concentration on the microphysics of continental thunderstorms, using a sample of storms from northwestern Oklahoma. The Weather Surveillance Radar-1988 Doppler (WSR-88D) at Vance Air Force Base (KVNX) was upgraded to dual-polarimetric capabilities in March 2011. Using polarimetric variables, a technique using ArcGIS (Geographic Information System) is used to identify the mean droplet characteristics. An estimate of the mean droplet size from the freezing level to 0.5 km above and the warm updraft depth above the ambient freezing level is developed for 36 continental thunderstorms within 15-20 minutes of convection initiation. Data from the Atmospheric Radiation Measurement (ARM) program at the Southern Great Plains (SGP) site are used to represent the aerosol concentration of the thunderstorm environment, and model soundings from the Rapid Update Cycle (RUC) and Rapid Refresh (RAP) Model are used to describe the storm environment. The RUC/RAP soundings were located approximate 59 km away from KVNX and were selected to represent the undisturbed far-field environment. Previous observational and modeling studies found effects of CCN concentration on thunderstorm characteristics including stronger updrafts as a result of enhanced latent heating, suppressed rain drop collision and coalescence, and altering the cold pool size. The results of this study provide more substantial observational evidence in support of these prior findings.
Advisor: Matthew S. Van Den Broek
Quaternized wood as sorbent for hexavalent chromium
The potential of quaternized wood (QW) chips in removing hexavalent chromium from synthetic solution and chrome waste under both batch and continuous-flow conditions was investigated. Sorption was found to be dependent on pH, metal concentration, and temperature. QW chips provide higher sorption capacity and wider pH range compared with untreated wood chips. The equilibrium data could be fitted into the Langmuir isotherm model, and maximum sorption capacities were calculated to be 27.03 and 25.77 mg/g in synthetic chromate solution and chrome waste, respectively. The presence of sulfate in high concentration appeared to suppress the uptake of chromium by QW chips. Column studies showed that bed depth influenced the breakthrough time greatly whereas flow rate of influent had little effect on its sorption on the column
The dilemma for lipid productivity in green microalgae: importance of substrate provision in improving oil yield without sacrificing growth
10.1186/s13068-016-0671-2Biotechnology for Biofuels911-1
A Mining-Based System Framework for Deploying Knowledge Maps of Composite E-Services
Providing e-services and composite e-services on the Internet is an important trend of e-business. Composite e-services are complex processes which consist of various e-services provided by different e-service providers. In such complex environments, the flexibility and success of e-business depend on effective knowledge supports to access related information and resources of composite e-services. This work proposes a knowledge map platform to provide an effective knowledge support for utilizing composite e-services. A mining-based system framework is proposed to construct the knowledge map. Moreover, the proposed knowledge map is integrated with recommendation capability to provide users customized decision support in utilizing composite e-services
Nitrogen-induced metabolic changes and molecular determinants of carbon allocation in Dunaliella tertiolecta
10.1038/srep37235Scientific Reports61-1
Exploring the transcriptome of non-model oleaginous microalga Dunaliella tertiolecta through high-throughput sequencing and high performance computing
GO analysis list. (DOCX 92Â kb
Risk factors for pulmonary tuberculosis in patients with chronic obstructive airway disease in Taiwan: a nationwide cohort study
BACKGROUND: An association between chronic obstructive pulmonary disease (COPD) and tuberculosis (TB) has been described, mainly due to smoking and corticosteroid use. Whether inhaled corticosteroid (ICS) therapy is associated with an increased risk of TB remains unclear. METHODS: We selected COPD cases by using six diagnostic scenarios and control subjects from a nationwide health insurance database, and applied time-dependent Cox regression analysis to identify the risk factors for TB. RESULTS: Among 1,000,000 beneficiaries, 23,594 COPD cases and 47,188 non-COPD control subjects were selected. Cox regression analysis revealed that age, male gender, diabetes mellitus, end-stage renal disease, and cirrhosis, as well as COPD (hazard ratio = 2.468 [2.205–2.762]) were independent risk factors for TB. Among the COPD cases, those who developed TB received more oral corticosteroids and oral β-agonists. Time-dependent Cox regression analysis revealed that age, male gender, diabetes mellitus, low income, oral corticosteroid dose, and oral β-agonist dose, but not ICS dose, were independent risk factors for TB. The identified risk factors and their hazard ratios were similar among the COPD cases selected using different scenarios. CONCLUSION: Keeping a high suspicion and regularly monitoring for the development of pulmonary TB in COPD patients are necessary, especially for those receiving higher doses of oral corticosteroids and other COPD medications. Although ICS therapy has been shown to predispose COPD patients to pneumonia in large randomized clinical trials, it does not increase the risk of TB in real world practice
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Raman-guided subcellular pharmaco-metabolomics for metastatic melanoma cells
Non-invasively probing metabolites within single live cells is highly desired but challenging. Here we utilize Raman spectro-microscopy for spatial mapping of metabolites within single cells, with the specific goal of identifying druggable metabolic susceptibilities from a series of patient-derived melanoma cell lines. Each cell line represents a different characteristic level of cancer cell de-differentiation. First, with Raman spectroscopy, followed by stimulated Raman scattering (SRS) microscopy and transcriptomics analysis, we identify the fatty acid synthesis pathway as a druggable susceptibility for differentiated melanocytic cells. We then utilize hyperspectral-SRS imaging of intracellular lipid droplets to identify a previously unknown susceptibility of lipid mono-unsaturation within de-differentiated mesenchymal cells with innate resistance to BRAF inhibition. Drugging this target leads to cellular apoptosis accompanied by the formation of phase-separated intracellular membrane domains. The integration of subcellular Raman spectro-microscopy with lipidomics and transcriptomics suggests possible lipid regulatory mechanisms underlying this pharmacological treatment. Our method should provide a general approach in spatially-resolved single cell metabolomics studies
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