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Wang, Yu

Publications and source records attributed to Wang, Yu.

At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Functional Gene Diversity and Metabolic Potential of the Microbial Community in an Estuary-Shelf Environment

Microbes play crucial roles in various biogeochemical processes in the ocean, including carbon (C), nitrogen (N), and phosphorus (P) cycling. Functional gene diversity and the structure of the microbial community determines its metabolic potential and therefore its ecological function in the marine ecosystem. However, little is known about the functional gene composition and metabolic potential of bacterioplankton in estuary areas. The East China Sea (ECS) is a dynamic marginal ecosystem in the western Pacific Ocean that is mainly affected by input from the Changjiang River and the Kuroshio Current. Here, using a high-throughput functional gene microarray (GeoChip), we analyzed the functional gene diversity, composition, structure, and metabolic potential of microbial assemblages in different ECS water masses. Four water masses determined by temperature and salinity relationship showed different patterns of functional gene diversity and composition. Generally, functional gene diversity [Shannon-Weaner's H and reciprocal of Simpson's 1/(1-D)] in the surface water masses was higher than that in the bottom water masses. The different presence and proportion of functional genes involved in C, N, and P cycling among the bacteria of the different water masses showed different metabolic preferences of the microbial populations in the ECS. Genes involved in starch metabolism ( amyA and nplT ) showed higher proportion in microbial communities of the surface water masses than of the bottom water masses. In contrast, a higher proportion of genes involved in chitin degradation was observed in microorganisms of the bottom water masses. Moreover, we found a higher proportion of nitrogen fixation ( nifH ), transformation of hydroxylamine to nitrite ( hao ) and ammonification ( gdh ) genes in the microbial communities of the bottom water masses compared with those of the surface water masses. The spatial variation of microbial functional genes was significantly correlated with salinity, temperature, and chlorophyll based on canonical correspondence analysis, suggesting a significant influence of hydrologic conditions on water microbial communities. Our data provide new insights into better understanding of the functional potential of microbial communities in the complex estuarine-coastal environmental gradient of the ECS.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Impact of the biorefinery size on the logistics of corn stover supply – A scenario analysis

In this study, three scenarios are considered to quantify the impact of the biorefinery size on the required biomass logistical resources. The biorefinery scenarios include small scale (175 dt/day)-SS, medium scale (520 dt/day)-MS and large scale (860 dt/day)-LS. These scenarios are compared against the following logistical resources (1) harvest area and contracted fields, (2) logistics equipment fleet and the workforce to run this fleet and (3) intermediate storage sites and their biomass inventory levels. To this end, the IBSAL-MC simulation model is applied to a corn stover logistics system in Southwestern Ontario. The obtained results show (1) the harvest area and the number of contracted fields increase by 65% and 78% from the SS scenario to the MS and LS scenarios, respectively, (2) the average biomass delivered costs are estimated to be $82.09, $87.49 and $93.75/dry tonne in the SS, MS and LS scenarios. The increase in the capital costs to develop a dedicated logistics equipment fleet are estimated to be far greater than the increase in the delivered costs as the size of the biorefinery increases. The upfront capital costs are estimated to be 6.72 dollars, 21.83 and 35.51 million in these scenarios. To run the logistics equipment fleet efficiently, 37, 136 and 235 well-trained operators are required in the SS, MS ad LS scenarios, respectively, and (3) the inventory level and the land requirement for storage in the MS and LS scenarios are estimated to be 225% and 425% greater than those of the SS scenario. The sensitivity analysis indicates that the logistical resources are highly sensitive to corn yield and farm participation rate. Overall, this study shows the importance of considering the size of the required logistical resources and the associated level of logistical complexity in evaluating the economic viability of a biorefinery project.

09 BIOMASS FUELS↗
DOE OSTI2016

Study on balance of axial force in helium circulator for HTR-PM - 18490

The helium circulator is one of the key equipment in the first loop of the High Temperature gas-cooled Reactor Pebble bed Module (HTR-PM). The active magnetic bearings are employed in the helium circulator, so that the inlet ring sealing clearance is about 5 to 10 times larger than that if the mechanical bearings are employed. Bigger clearance results in bigger leakage flow and bigger axial force. A new design of balance holes was proposed to reduce the axial aerodynamic force and the design principle was analyzed. To investigate the axial aerodynamic force due to leakage flow, numerical simulation of fluid dynamic was conducted in the impeller with two kinds of inlet ring sealing clearance and four types of balance holes, respectively. The calculation results shows that the balance holes with diameter 12 mm have high performance and that the designed balance holes reduce effectively about 78% of the axial aerodynamic force. The axial force was obtained from the measured real-time electric current of the axial active magnetic bearings in one helium circulator prototype. The comparison of experimental data with the CFD analysis results showed that the new design of balance holes was successful. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2016

New leak assembly based on fluidic nanochannels

Fluidic nanochannels with a characteristic dimension of ∼280 nm were fabricated and designed as a leak assembly, where the nanochannels were formed on silicon wafers and enclosed with Pyrex{sup ®} glass. The geometric dimensions were characterized by scanning electron microscopy, and the gas flow conductance of He and other heavy gases (N{sub 2}, O{sub 2}, and Ar) was measured, and its uncertainty estimated, by the difference method. The results indicated that the measured flow conductance values were 45% less than the calculated flow conductance values. For helium, molecular flow was shown to occur at pressures ranging from vacuum to atmospheric pressure. As a consequence of the well-defined geometry, the prediction of flow conductance could be achieved for various gas species.

42 ENGINEERING↗
DOE OSTI2016

Effects and mechanisms of cavidine protecting mice against LPS-induced endotoxic shock

LPS sensitized mice are usually considered as an experimental model of endotoxin shock. The present study aims to evaluate effects of cavidine on LPS-induced endotoxin shock. Mice were intraperitoneally administrated with cavidine (1, 3 and 10 mg/kg) or DEX (5 mg/kg) at 1 and 12 h before injecting LPS (30 mg/kg) intraperitoneally. Blood samples, liver, lung and kidney tissues were harvested after LPS injection. The study demonstrated that pretreatment with cavidine reduced the mortality of mice during 72 h after endotoxin injection. In addition, cavidine administration significantly attenuated histological pathophysiology features of LPS-induced injury in lung, liver and kidney. Furthermore, cavidine administration inhibited endotoxin-induced production of pro-inflammatory cytokines including TNF-α, IL-6 and HMGB1. Moreover, cavidine pretreatment attenuated the phosphorylation of mitogen-activated protein kinase primed by LPS. In summary, cavidine protects mice against LPS-induced endotoxic shock via inhibiting early pro-inflammatory cytokine TNF-α, IL-6 and late-phase cytokine HMGB1, and the modulation of HMGB1 may be related with MAPK signal pathway. - Highlights: • Cavidine significantly reduced mortality in mice during 72 h after LPS injection. • Cavidine attenuated histopathological changes in lung, liver and kidney. • Cavidine decreased the level of early inflammatory cytokine TNF-α, IL-6 in LPS- stimulated mice. • Cavidine inhibited late inflammatory cytokine HMGB1 through MAPK pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Key technologies and applications of laser cooling and trapping {sup 87}Rb atomic system

Atom Interferometry is proved to be a potential method for measuring the acceleration of atoms due to Gravity, we are now building a feasible system of cold atom gravimeter. In this paper development and the important applications of laser cooling and trapping atoms are introduced, some key techniques which are used to obtain {sup 87}Rb cold atoms in our experiments are also discussed.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2016

Goos-Hänchen-like shift in biased silicene

We have theoretically studied the Goos-Hänchen-like shift of spinor-unpolarized beams tunneling through various gate-biased silicene nanostructures. Following the stationary-phase method, lateral displacement in single-, dual-, and multiple-gated silicene systems has been systematically demonstrated. It is shown for simple single-gated silicene that lateral displacement can be generally enhanced by Fabry-Perot interference, and near the transition point turning on the evanescent mode a very large lateral shift could be observed. For the dual-gated structure, we have also shown the crucial role of localized modes like quantum well states in enhancing the beam lateral displacement, while for the multiple gate-biased systems the resulting superlattice subbands are also favorable for lateral displacement enhancement. Importantly, including the degeneracy-broken mechanisms such as gate-field and magnetic modulations, a fully spinor-resolved beam can be distinguished from the rest counterparts by aligning the incident beam with a proper spinor-resolved transition point, localized state, and subband, all of which can be flexibly modulated via electric means, offering the very desirable strategies to achieve the fully spinor-polarized beam for functional electronic applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Facile and high spatial resolution ratio-metric luminescence thermal mapping in microfluidics by near infrared excited upconversion nanoparticles

A local area temperature monitor is important for precise control of chemical and biological processes in microfluidics. In this work, we developed a facile method to realize micron spatial resolution of temperature mapping in a microfluidic channel quickly and cost effectively. Based on the temperature dependent fluorescence emission of NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} upconversion nanoparticles (UCNPs) under near-infrared irradiation, ratio-metric imaging of UCNPs doped polydimethylsiloxane can map detailed temperature distribution in the channel. Unlike some reported strategies that utilize temperature sensitive organic dye (such as Rhodamine) to achieve thermal sensing, our method is highly chemically inert and physically stable without any performance degradation in long term operation. Moreover, this method can be easily scaled up or down, since the spatial and temperature resolution is determined by an optical imaging system. Our method supplied a simple and efficient solution for temperature mapping on a heterogeneous surface where usage of an infrared thermal camera was limited.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Bacterioplankton community resilience to ocean acidification: evidence from microbial network analysis

Ocean acidification (OA), caused by seawater CO 2 uptake, has significant impacts on marine calcifying organisms and phototrophs. However, the response of bacterial communities, who play a crucial role in marine biogeochemical cycling, to OA is still not well understood. Previous studies have shown that the diversity and structure of microbial communities change undeterminably with elevated p CO 2 . Here, novel phylogenetic molecular ecological networks (pMENs) were employed to investigate the interactions of native bacterial communities in response to OA in the Arctic Ocean through a mesocosm experiment. The pMENs results were in line with the null hypothesis that elevated p CO 2 /pH does not affect biogeochemistry processes. The number of nodes within the pMENs and the connectivity of the bacterial communities were similar, despite increased p CO 2 concentrations. Our results indicate that elevated p CO 2 did not significantly affect microbial community structure and succession in the Arctic Ocean, suggesting bacterioplankton community resilience to elevated p CO 2 . The competitive interactions among the native bacterioplankton, as well as the modular community structure, may contribute to this resilience. This pMENs-based investigation of the interactions among microbial community members at different p CO 2 concentrations provides a new insight into our understanding of how OA affects the microbial community.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Three-Dimensional Radiation Therapy to the Primary Tumor With Concurrent Chemotherapy in Patients With Stage IV Non-Small Cell Lung Cancer: Results of a Multicenter Phase 2 Study From PPRA-RTOG, China

Purpose: The aim of this prospective multi-institutional phase 2 study was to investigate disease control, survival outcomes, and toxicity after thoracic three-dimensional radiation therapy (3D-RT) with concurrent chemotherapy for newly diagnosed stage IV non-small cell lung cancer (NSCLC). Methods and Materials: Eligible patients were 18 to 80 years of age, had a Karnofsky performance status (KPS) score ≥70%, and newly diagnosed stage IV NSCLC with limited metastatic disease (defined as involving ≤3 organs). Patients received platinum-doublet chemotherapy with concurrent irradiation to the primary tumor. Primary endpoints were overall survival (OS) and acute toxicity. Results: From May 2008 to May 2012, 198 eligible patients were enrolled from 7 cancer centers. Most patients died with distant metastasis; only 10% died with isolated primary recurrence. Median OS time was 13.0 months (95% confidence interval [CI]: 11.7-14.3); OS rates were 53.5% at 1 year, 15.8% at 2 years, and 9.2% at 3 years. Median progression-free survival (PFS) time was 9.0 months (95% CI: 7.7-10.3); corresponding PFS rates were 30.8%, 8.2%, and 6.1%. The 1-year, 2-year, and 3-year local (primary tumor) control rates were 78.8%, 57.7%, and 55.4%. Multivariate analysis showed that delivery of ≥63 Gy to the primary tumor (P=.014), having a primary tumor volume <134 cm{sup 3} (P=.008), and having a stable or higher KPS score after treatment (P=.01) were independent predictors of better OS. The most common severe (grades 3-4) acute toxicities were hematologic: leukopenia (37.9%), thrombocytopenia (10.1%), and anemia (6.9%). No patients experienced grade 4 or 5 radiation-related toxicity; 2.5% had acute grade 3 pneumonitis, and 6.6% had acute grade 3 radiation esophagitis. Conclusions: Thoracic 3D-RT to the primary tumor with concurrent chemotherapy led to satisfactory survival outcomes with acceptable toxicity. Radiation dose, primary tumor volume, and PFS after treatment all predicted survival in these patients with limited-metastasis NSCLC.

62 RADIOLOGY AND NUCLEAR MEDICINE↗