bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Rebound Testing for Evaluation of Soil Vapor Extraction Performance at the Savannah River Site
Authors: Switzer Christine , Slagle Timothy , Hunter Donald , Kosson David S. 
Published: November 2010

AbstractIn 1999, a pilot soil vapor extraction (SVE) system was installed at a waste area within the Department of Energy's Savannah River Site located near Aiken, South Carolina, to remediate trichloroethylene (TCE) contamination and to evaluate monitoring and operational strategies for SVE application in layered heterogeneous materials. The specific objectives of the results reported here were (1) to evaluate the use of rebound analysis of soil gas concentrations as the basis for operational strategies, and (2) establish the endpoint criteria for active remedial action. Three soil gas TCE concentration rebound tests were conducted over a period of 18 months to assess system performance and progress. For each rebound test, the system was shut down and allowed to equilibrate for two to four weeks. Soil gas TCE concentrations were measured several times during this equilibration period. Comparison of these rebound test results has been used for evaluating SVE system performance. A transient two‐dimensional diffusion model has been used to convert soil gas TCE rebound concentrations to estimates from distance to source, and the model predictions correspond with observed dense nonaqueous phase liquid at the site. Also, these rebound tests can provide sufficient information about contaminant distribution and SVE mass transfer limitations to select a reasonable and appropriate endpoint for active remedial operations.
Determining the Critical Relative Humidity at which the Glassy to Rubbery Transition Occurs in Polydextrose Using an Automatic Water Vapor Sorption Instrument
Authors: Yuan Xiaoda , Carter Brady P. , Schmidt Shelly J. 
Published: November 2010

Abstract:  Similar to an increase in temperature at constant moisture content, water vapor sorption by an amorphous glassy material at constant temperature causes the material to transition into the rubbery state. However, comparatively little research has investigated the measurement of the critical relative humidity (RHc) at which the glass transition occurs at constant temperature. Thus, the central objective of this study was to investigate the relationship between the glass transition temperature (Tg), determined using thermal methods, and the RHc obtained using an automatic water vapor sorption instrument. Dynamic dewpoint isotherms were obtained for amorphous polydextrose from 15 to 40 °C. RHc was determined using an optimized 2nd‐derivative method; however, 2 simpler RHc determination methods were also tested as a secondary objective. No statistical difference was found between the 3 RHc methods. Differential scanning calorimetry (DSC) Tg values were determined using polydextrose equilibrated from 11.3% to 57.6% RH. Both standard DSC and modulated DSC (MDSC) methods were employed, since some of the polydextrose thermograms exhibited a physical aging peak. Thus, a tertiary objective was to compare Tg values obtained using 3 different methods (DSC first scan, DSC rescan, and MDSC), to determine which method(s) yielded the most accurate Tg values. In general, onset and midpoint DSC first scan and MDSC Tg values were similar, whereas onset and midpoint DSC rescan values were different. State diagrams of RHc and experimental temperature and Tg and %RH were compared. These state diagrams, though obtained via very different methods, showed relatively good agreement, confirming our hypothesis that water vapor sorption isotherms can be used to directly detect the glassy to rubbery transition.Practical Application:  The food polymer science (FPS) approach, pioneered by Slade and Levine, is being successfully applied in the food industry for understanding, improving, and developing food processes and products. However, despite its extreme usefulness, the Tg, a key element of the FPS approach, remains a challenging parameter to routinely measure in amorphous food materials, especially complex materials. This research demonstrates that RHc values, obtained at constant temperature using an automatic water vapor sorption instrument, can be used to detect the glassy to rubbery transition and are similar to the Tg values obtained at constant %RH, especially considering the very different approaches of these 2 methods—a transition from surface adsorption to bulk absorption (water vapor sorption) versus a step change in the heat capacity (DSC thermal method).
Graduated Resistance to Gas Flow Through a GDL in an Unconventional PEM Stack
Authors: Caston Terry B. , Bhamidipati Kanthi L. , Carney Haley , Harris Tequila A. L. 
Published: November 2010

Abstract
The goal of this study is to design a gas diffusion layer (GDL) for a polymer electrolyte membrane (PEM) fuel cell with a graduated permeability and thereby graduating the resistance to flow throughout the GDL. It has been shown that in using conventional materials, the GDL exhibits a higher resistance in the through-plane direction due to the orientation of the small carbon fibers that make up the carbon paper or carbon cloth. In this study, a GDL is designed for an unconventional PEM fuel cell stack where the reactant gases are supplied through the side of the GDL rather than through flow field channels machined into a bipolar plate. The effects of changing in-plane permeability, through-plane permeability, GDL thickness, and oxygen utilization on the expected current density distribution at the catalyst layer are studied. Three different thicknesses and three different utilizations are investigated. It has been found that a thinner GDL with a lower utilization yields a higher current density on the electrode. A quantitative metric to measure uniformity of reactant distribution and the ratio of the standard deviation of the current density to the average current density was introduced, and it was found that while the uniformity of the reactant distribution is independent of thickness of the GDL, it is inversely proportional to utilization.
Heat and Mass Transfer on the MHD Fluid Flow Due to a Porous Rotating
Disk With Hall Current and Variable Properties
Authors: Turkyilmazoglu Mustafa 
Published: November 2010

Abstract
The steady magnetohydrodynamics (MHD) laminar compressible flow of an electrically conducting fluid on a porous rotating disk is considered in the present paper. The governing equations of motion are reduced to a set of nonlinear differential equations by means of similarity transformations. The fluid properties are taken to be strong functions of temperature and Hall current that also readily accounts for the viscous dissipation and Joule heating terms. Employing a highly accurate spectral numerical integration scheme, the effects of viscosity, thermal conductivity, Hall current, magnetic field, suction/injection, viscous dissipation, and Joule heating on the considered flow are examined. The quantities of particular physical interest, such as the torque, the wall shear stresses, the vertical suction velocity, and the rate of heat transfer are calculated and discussed.
Use of Microcalorimetry To Determine the Costs and Benefits to
Pseudomonas putida
Strain KT2440 of Harboring Cadmium Efflux Genes
Authors: Gibbons Sean M. , Feris Kevin , McGuirl Michele A. , Morales Sergio E. , Hynninen Anu , Ramsey Philip W. , Gannon James E. 
Published: November 2010

ABSTRACT

A novel microcalorimetric approach was used to analyze the responses of a metal-tolerant soil bacterium (
Pseudomonas putida
strain KT2440) to metal resistance gene deletions in cadmium-amended media. As hypothesized, under cadmium stress, the wild-type strain benefited from the resistance genes by entering the exponential growth phase earlier than two knockout strains. In the absence of cadmium, strain KT1, carrying a deletion in the main component (
czcA1
) of a Cd/Zn chemiosmotic efflux transporter (CzcCBA1), grew more efficiently than the wild type and released ∼700 kJ (per mole of biomass carbon) less heat than the wild-type strain, showing the energetic cost of maintaining CzcCBA1 in the absence of cadmium. A second mutant strain (KT4) carrying a different gene deletion, Δ
cadA2
, which encodes the main Cd/Pb efflux transporter (a P-type ATPase), did not survive beyond moderate cadmium concentrations and exhibited a decreased growth yield in the absence of cadmium. Therefore, CadA2 plays an essential role in cadmium resistance and perhaps serves an additional function. The results of this study provide direct evidence that heavy metal cation efflux mechanisms facilitate shorter lag phases in the presence of metals and that the maintenance and expression of tolerance genes carry quantifiable energetic costs and benefits.
Inactivation of
Ascaris suum
by Short-Chain Fatty Acids
Authors: Butkus Michael A. , Hughes Kelly T. , Bowman Dwight D. , Liotta Janice L. , Jenkins Michael B. , Labare Michael P. 
Published: November 2010

ABSTRACT

Ascaris suum
eggs were inactivated in distilled water and digested sludge by butanoic, pentanoic, and hexanoic acids. The fatty acids (short-chain fatty acids [SCFA]) were effective only when protonated and at sufficient concentrations. The conjugate bases were not effective at the concentrations evaluated. Predictions from an inhibition model (50% inhibitory concentration [IC
50
]) based on quantitative structure-activity relationships were congruent with inactivation data.
Mercury and Other Heavy Metals Influence Bacterial Community Structure in Contaminated Tennessee Streams
Authors: Vishnivetskaya Tatiana A. , Mosher Jennifer J. , Palumbo Anthony V. , Yang Zamin K. , Podar Mircea , Brown Steven D. , Brooks Scott C. , Gu Baohua , Southworth George R. , Drake Meghan M. , Brandt Craig C. , Elias Dwayne A. 
Published: November 2010

ABSTRACTHigh concentrations of uranium, inorganic mercury [Hg(II)], and methylmercury (MeHg) have been detected in streams located in the Department of Energy reservation in Oak Ridge, TN. To determine the potential effects of the surface water contamination on the microbial community composition, surface stream sediments were collected 7 times during the year, from 5 contaminated locations and 1 control stream. Fifty-nine samples were analyzed for bacterial community composition and geochemistry. Community characterization was based on GS 454 FLX pyrosequencing with 235 Mb of 16S rRNA gene sequence targeting the V4 region. Sorting and filtering of the raw reads resulted in 588,699 high-quality sequences with lengths of >200 bp. The bacterial community consisted of 23 phyla, includingProteobacteria(ranging from 22.9 to 58.5% per sample),Cyanobacteria(0.2 to 32.0%),Acidobacteria(1.6 to 30.6%),Verrucomicrobia(3.4 to 31.0%), and unclassified bacteria. Redundancy analysis indicated no significant differences in the bacterial community structure between midchannel and near-bank samples. Significant correlations were found between the bacterial community and seasonal as well as geochemical factors. Furthermore, several community members within theProteobacteriagroup that includes sulfate-reducing bacteria and within theVerrucomicrobiagroup appeared to be associated positively with Hg and MeHg. This study is the first to indicate an influence of MeHg on thein situmicrobial community and suggests possible roles of these bacteria in the Hg/MeHg cycle.
Complex Regulation of Symbiotic Functions Is Coordinated by MucR and Quorum Sensing in
Sinorhizobium meliloti
Authors: Mueller Konrad , González Juan E. 
Published: November 2010

ABSTRACT

In
Sinorhizobium meliloti
, the production of exopolysaccharides such as succinoglycan and exopolysaccharide II (EPS II) enables the bacterium to invade root nodules on
Medicago sativa
and establish a nitrogen-fixing symbiosis. While extensive research has focused on succinoglycan, less is known concerning the regulation of EPS II or the mechanism by which it mediates entrance into the host plant. Previously, we reported that the ExpR/Sin quorum-sensing system is required to produce the symbiotically active low-molecular-weight fraction of this exopolysaccharide. Here, we show that this system induces EPS II production by increasing expression of the
expG-expC
operon, encoding both a transcriptional regulator (ExpG) and a glycosyl transferase (ExpC). ExpG derepresses EPS II production at the transcriptional level from MucR, a RosR homolog, while concurrently elevating expression of
expC
, resulting in the synthesis of the low-molecular-weight form. While the ExpR/Sin system abolishes the role of MucR on EPS II production, it preserves a multitude of other quorum-sensing-independent regulatory functions which promote the establishment of symbiosis. In planktonic
S. meliloti
, MucR properly coordinates a diverse set of bacterial behaviors by repressing a variety of genes intended for expression during symbiosis and enhancing the bacterial ability to induce root nodule formation. Quorum sensing precisely modulates the functions of MucR to take advantage of both the production of symbiotically active EPS II as well as the proper coordination of bacterial behavior required to promote symbiosis.
Mathematical and Experimental Approaches to Identify and Predict the Effects of Chemotherapy on Neuroglial Precursors
Authors: Hyrien Ollivier , Dietrich Jörg , Noble Mark 
Published: November 2010

Abstract
The adverse effects of chemotherapy on normal cells of the body create substantial clinical problems for many cancer patients. However, relatively little is known about the effects, other than promotion of cell death, of such agents on the function of normal precursor cells critical in tissue homeostasis and repair. We have combined mathematical and experimental analyses to identify the effects of sublethal doses of chemotherapy on glial precursor cells of the central nervous system. We modeled the temporal development of a population of precursor and terminally differentiated cells exposed to sublethal doses of carmustine (BCNU), a classic alkylating chemotherapeutic agent used in treatment of gliomas and non-Hodgkin's lymphomas, as a multitype age-dependent branching process. We fitted our model to data from in vitro clonal experiments using the method of pseudo-likelihood. This approach identifies several novel drug effects, including modification of the cell cycle length, the time between division and differentiation, and alteration in the probability of undergoing self-renewal division in precursor cells. These changes of precursor cell function in the chemotherapy-exposed brain may have profound clinic implications.
Major Findings: We applied our computational approach to analyze the effects of BCNU on clonal cultures of oligodendrocyte progenitor cells—one of the best-characterized neural progenitor cells in the mammalian brain. Our analysis reveals that transient exposures to BCNU increased the cell cycle length of progenitor cells and decreased their time to differentiation, while also decreasing the likelihood that they will undergo self-renewing divisions. By investigating the behavior of our mathematical model, we demonstrate that precursor cell populations should recover spontaneously from transient modifications of the timing of division and of differentiation, but such recovery will not happen after alteration of cell fate. These studies identify means by which precursor cell function can be critically compromised by transient exposure to chemotherapy with long-term consequences on the progenitor cell pool even in the absence of drug-induced apoptosis. These analyses also provide novel tools that apply broadly to identify effects of chemotherapeutic agents and other physiological stressors. Cancer Res; 70(24); 10051–9. ©2010 AACR.
p53 Dysfunction by Xeroderma Pigmentosum Group C Defects Enhance Lung Adenocarcinoma Metastasis via Increased Mmp1 Expression
Authors: Wu Yi-Hui , Wu Tzu-Chin , Liao Jiunn-Wang , Yeh Kun-Tu , Chen Chih-Yi , Lee Huei 
Published: November 2010

Abstract
Xeroderma pigmentosum group C (XPC) interacts with hHR23B to recognize DNA damage in global genomic repair. We previously showed that XPC is predominantly affected by its hypermethylation and is associated with an increased occurrence of p53 mutation in lung cancer. Tumors with low XPC mRNA levels had a poorer prognosis than those with high XPC mRNA levels, suggesting that XPC defects may enhance tumor metastasis. However, the underlying mechanism is unclear. Here, we show that p53 transcriptional activity is modulated by XPC, whereby XPC stabilizes hHR23B to form an hHR23B–p53 complex that prevents p53 degradation. In addition, in lung cancer cells and xenograft tumors in nude mice, overexpression of XPC suppresses cell/tumor metastatic ability via repression of matrix metalloproteinase-1 (MMP1) transcription by p53. Among tumors from lung cancer patients, those with low XPC mRNA also tended to have low expression of MMP1 mRNA compared with those with high XPC mRNA. Patients with low XPC mRNA levels also more commonly had tumors with late-stage, distant metastasis (M1), nodal metastasis, and T value (P &lt; 0.001 for tumor stage, distant metastasis, and nodal metastasis; P = 0.006 for t value). In conclusion, p53 dysfunction caused by XPC defects in lung cancers may enhance tumor metastasis via increased MMP1 expression. Cancer Res; 70(24); 10422–32. ©2010 AACR.
Oridonin induces apoptosis and senescence in colorectal cancer cells by increasing histone hyperacetylation and regulation of p16, p21, p27 and c-myc
Authors: Gao Feng-Hou , Hu Xiao-Hui , Li Wei , Liu Hua , Zhang Yan-Jie , Guo Zhu-Ying , Xu Mang-Hua , Wang Shi-Ting , Jiang Bin , Liu Feng , Zhao Ying-Zheng , Fang Yong , Chen Fang-Yuan , Wu Ying-Li 
Published: November 2010

Abstract

Background
Oridonin, a tetracycline diterpenoid compound, has the potential antitumor activities. Here, we evaluate the antitumor activity and action mechanisms of oridonin in colorectal cancer.

Methods
Effects of oridonin on cell proliferation were determined by using a CCK-8 Kit. Cell cycle distribution was determined by flow cytometry. Apoptosis was examined by analyzing subdiploid population and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Senescent cells were determined by senescence-associated β-galactosidase activity analysis. Semi-quantitative RT-PCR was used to examine the changes of mRNA of p16, p21, p27 and c-myc. The concomitant changes of protein expression were analyzed with Western blot. Expression of AcH3 and AcH4 were examined by immunofluorescence staining and Western blots. Effects of oridonin on colony formation of SW1116 were examined by Soft Agar assay. The in vivo efficacy of oridonin was detected using a xenograft colorectal cancer model in nude mice.

Results
Oridonin induced potent growth inhibition, cell cycle arrest, apoptosis, senescence and colony-forming inhibition in three colorectal cancer cell lines in a dose-dependent manner in vitro. Daily i.p. injection of oridonin (6.25, 12.5 or 25 mg/kg) for 28 days significantly inhibited the growth of SW1116 s.c. xenografts in BABL/C nude mice. With western blot and reverse transcription-PCR, we further showed that the antitumor activities of oridonin correlated with induction of histone (H3 and H4) hyperacetylation, activation of p21, p27 and p16, and suppression of c-myc expression.

Conclusion
Oridonin possesses potent in vitro and in vivo anti-colorectal cancer activities that correlated with induction of histone hyperacetylation and regulation of pathways critical for maintaining growth inhibition and cell cycle arrest. Therefore, oridonin may represent a novel therapeutic option in colorectal cancer treatment.
On dimension of the Schur multiplier of nilpotent Lie algebras
Authors: Niroomand Peyman 
Published: November 2010

Abstract
Let L be an n-dimensional non-abelian nilpotent Lie algebra and $$
s(L) = \frac{1}
{2}(n - 1)(n - 2) + 1 - \dim M(L)
$$ where M(L) is the Schur multiplier of L. In [Niroomand P., Russo F., A note on the Schur multiplier of a nilpotent Lie algebra, Comm. Algebra (in press)] it has been shown that s(L) ≥ 0 and the structure of all nilpotent Lie algebras has been determined when s(L) = 0. In the present paper, we will characterize all finite dimensional nilpotent Lie algebras with s(L) = 1; 2.
Symmetry and models of single-walled TiO2 nanotubes with rectangular morphology
Authors: Evarestov Robert , Zhukovskii Yuri , Bandura Andrei , Piskunov Sergei 
Published: November 2010

Abstract
The formalism of line symmetry groups for one-periodic (1D) nanostructures with rotohelical symmetry has been applied for symmetry analysis of single-walled titania nanotubes (SW TiO2 NTs) formed by rolling up the stoichiometric two-periodic (2D) slabs of anatase structure. Either six- or twelve-layer (101) slabs have been cut from TiO2 crystal in a stable anatase phase. After structural optimization, the latter keeps the centered rectangular symmetry of initial slab slightly compressed along a direction coincided with large sides of elemental rectangles. We have considered two sets of SW TiO2 NTs with optimized six- and twelve-layer structures, which possess chiralities (−n, n) and (n, n) of anatase nanotubes. To analyze the structural and electronic properties of titania slabs and nanotubes, we have performed their ab initio LCAO calculations, using the hybrid Hartree-Fock/Kohn-Sham exchange-correlation functional PBE0. The band gaps (Δɛ
gap) and strain energies (E
strain) of six-layer nanotubes have been computed and analyzed as functions of NT diameter (D
NT). As to models of 12-layer SW TiO2 NTs of both chiralities, their optimization results in structural exfoliation, i.e., the multi-walled structure should be rather formed in nanotubes with such a number of atomic layers.
Fluid dynamics of flow through microscale lattice structures formed from self‐propagating photopolymer waveguides
Authors: Fink Kathryn D. , Kolodziejska Joanna A. , Jacobsen Alan J. , Roper Christopher S. 
Published: November 2010

AbstractThe fluid dynamics of flow through microscale lattice structures is characterized for different unit cell sizes, flow angles, and flow rates. The structures consist of an octahedral‐type periodic unit cell, which is formed from an interconnected pattern of self‐propagating photopolymer waveguides. The periodic unit cell of each sample has a node‐to‐node spacing between 800 and 2400 μm and a truss member diameter between 148 and 277 μm. Water is directed through the microscale lattice structures, and the resulting pressure drop is investigated for two different flow angles and superficial flow rates between 0.5 and 4.8 L/min. Finite element analysis is used to determine pressure drop in the laminar flow regime. The results are used to develop a correlation describing friction factor as a function of flow direction, geometric characteristics, and Reynolds number. This work enables control of the fluid dynamics in microarchitected multifunctional truss materials through design and superficial flow angle. © 2010 American Institute of Chemical Engineers AIChE J, 2011