Photoelectron Spectroscopic Study of the Oxyallyl Diradical (open access)

Photoelectron Spectroscopic Study of the Oxyallyl Diradical

Article on a photoelectron spectroscopic study of the oxyallyl diradical.
Date: February 16, 2011
Creator: Ichino, Takatoshi; Villano, Stephanie M.; Gianola, Adam J.; Goebbert, Daniel J.; Velarde, Luis; Sanov, Andrei et al.
System: The UNT Digital Library
Experimental and Computational Studies of the Isomerization Reactions of Bidentate Phosphine Ligands in Triosmium Clusters: Kinetics of the Rearrangements from Bridged to Chelated Isomers and X-ray Structures of the Clusters Os3 (CO)10 (dppbz), 1,1-Os3 (CO)10 (dppbzF4), HOs3 (CO)9 [μ -1,2-PhP (C6H4-ɳ1) C6H4PPh2], and HOs3 (CO)9- [μ-1,2-PhP (C6H4-ɳ 1) C6F4PPh2] (open access)

Experimental and Computational Studies of the Isomerization Reactions of Bidentate Phosphine Ligands in Triosmium Clusters: Kinetics of the Rearrangements from Bridged to Chelated Isomers and X-ray Structures of the Clusters Os3 (CO)10 (dppbz), 1,1-Os3 (CO)10 (dppbzF4), HOs3 (CO)9 [μ -1,2-PhP (C6H4-ɳ1) C6H4PPh2], and HOs3 (CO)9- [μ-1,2-PhP (C6H4-ɳ 1) C6F4PPh2]

Article on experimental and computational studies of the isomerization reactions of bidentate phosphine ligands in triosmium clusters.
Date: February 22, 2011
Creator: Zhang, Xue; Kandala, Srikanth; Yang, Li; Watson, William H.; Wang, Xiaoping; Hrovat, David A. et al.
System: The UNT Digital Library
The Ecoresponsive Genome of Daphnia pulex (open access)

The Ecoresponsive Genome of Daphnia pulex

This article discusses the ecoresponsive genome of Daphnia pulex.
Date: February 4, 2011
Creator: Colbourne, John K.; Pfrender, Michael E.; Gilbert, Donald; Thomas, W. Kelley; Tucker, Abraham; Oakley, Todd H. et al.
System: The UNT Digital Library
Is Qualitative Research Second Class Science? A Quantitative Longitudinal Examination of Qualitative Research in Medical Journals (open access)

Is Qualitative Research Second Class Science? A Quantitative Longitudinal Examination of Qualitative Research in Medical Journals

Article discussing the proportion of qualitative research over a 10 year period and correlates associated with its publication.
Date: February 2011
Creator: Shuval, Kerem; Harker, Karen; Roudsari, Bahman; Groce, Nora Ellen, 1952-; Mills, Britain A.; Siddiqi, Zoveen et al.
System: The UNT Digital Library
Environmental and Genetic Preconditioning for Long-Term Anoxia Responses Requires AMPK in Caenorhabditis elegans (open access)

Environmental and Genetic Preconditioning for Long-Term Anoxia Responses Requires AMPK in Caenorhabditis elegans

Article on environmental and genetic preconditioning for long-term anoxia responses requires AMPK in Caenorhabditis elegans.
Date: February 3, 2011
Creator: LaRue, Bobby L. & Padilla, Pamela A.
System: The UNT Digital Library
Reciprocal Suffering: Caregiver Concerns During Hospice Care (open access)

Reciprocal Suffering: Caregiver Concerns During Hospice Care

Article on caregiver concerns during hospice care and reciprocal suffering.
Date: February 2011
Creator: Wittenberg-Lyles, Elaine; Demiris, George; Oliver, Debra Parker & Burt, Stephanie
System: The UNT Digital Library
Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates (open access)

Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates

Replacement of methane with carbon dioxide in hydrate has been proposed as a strategy for geologic sequestration of carbon dioxide (CO{sub 2}) and/or production of methane (CH{sub 4}) from natural hydrate deposits. This replacement strategy requires a better understanding of the thermodynamic characteristics of binary mixtures of CH{sub 4} and CO{sub 2} hydrate (CH{sub 4}-CO{sub 2} mixed hydrates), as well as thermophysical property changes during gas exchange. This study explores the thermal dissociation behavior and dissociation enthalpies of CH{sub 4}-CO{sub 2} mixed hydrates. We prepared CH{sub 4}-CO{sub 2} mixed hydrate samples from two different, well-defined gas mixtures. During thermal dissociation of a CH{sub 4}-CO{sub 2} mixed hydrate sample, gas samples from the head space were periodically collected and analyzed using gas chromatography. The changes in CH{sub 4}-CO{sub 2} compositions in both the vapor phase and hydrate phase during dissociation were estimated based on the gas chromatography measurements. It was found that the CO{sub 2} concentration in the vapor phase became richer during dissociation because the initial hydrate composition contained relatively more CO{sub 2} than the vapor phase. The composition change in the vapor phase during hydrate dissociation affected the dissociation pressure and temperature; the richer CO{sub 2} in the vapor …
Date: February 15, 2011
Creator: Kwon, T.H.; Kneafsey, T.J. & Rees, E.V.L.
System: The UNT Digital Library
Order and disorder in the local and long-range structure of the spin-glass pyrochlore, Tb{sub 2}Mo{sub 2}O{sub 7} (open access)

Order and disorder in the local and long-range structure of the spin-glass pyrochlore, Tb{sub 2}Mo{sub 2}O{sub 7}

To understand the origin of the spin-glass state in molybdate pyrochlores, the structure of Tb{sub 2}Mo{sub 2}O{sub 7} is investigated using two techniques: the long-range lattice structure was measured using neutron powder diffraction (NPD), and local structure information was obtained from the extended x-ray absorption fine structure (EXAFS) technique. While the long-range structure appears generally well ordered, enhanced mean-squared site displacements on the O(1) site and the lack of temperature dependence of the strongly anisotropic displacement parameters for both the Mo and O(1) sites indicate some disorder exists. Likewise, the local structure measurements indicate some Mo-Mo and Tb-O(1) nearest-neighbor disorder exists, similar to that found in the related spin-glass pyrochlore, Y{sub 2}Mo{sub 2}O{sub 7}. Although the freezing temperature in Tb{sub 2}Mo{sub 2}O{sub 7}, 25 K, is slightly higher than in Y{sub 2}Mo{sub 2}O{sub 7}, 22 K, the degree of local pair distance disorder is actually less in Tb{sub 2}Mo{sub 2}O{sub 7}. This apparent contradiction is considered in light of the interactions involved in the freezing process.
Date: February 11, 2011
Creator: Jiang, Yu; Huq, Ashfia; Booth, Corwin H.; Ehlers, Georg; Greedan, John E. & Gardner, Jason S.
System: The UNT Digital Library
X-ray imaging of vortex cores in confined magnetic structures (open access)

X-ray imaging of vortex cores in confined magnetic structures

Cores of magnetic vortices in micron-sized NiFe disk structures, with thicknesses between 150 and 50 nm, were imaged and analysed by high resolution magnetic soft X-ray microscopy. A decrease of the vortex core radius was observed, from #24; ~38 to 18 nm with decreasing disk thickness. By comparing with full 3D micromagnetic simulations showing the well-known barrel structure, we obtained excellent agreement taking into account instrumental broadening and a small perpendicular anisotropy. The proven magnetic spatial resolution of better than 25 nm was sufficient to identify a negative dip close to the vortex core, originating from stray fields of the core. Magnetic vortex structures can serve as test objects for evaluating sensitivity and spatial resolution of advanced magnetic microscopy techniques.
Date: February 11, 2011
Creator: Fischer, P.; Im, M.-Y.; Kasai, S.; Yamada, K.; Ono, T. & Thiaville, A.
System: The UNT Digital Library
Identification of a haloalkaliphilic and thermostable cellulase with improved ionic liquid tolerance (open access)

Identification of a haloalkaliphilic and thermostable cellulase with improved ionic liquid tolerance

Some ionic liquids (ILs) have been shown to be very effective solvents for biomass pretreatment. It is known that some ILs can have a strong inhibitory effect on fungal cellulases, making the digestion of cellulose inefficient in the presence of ILs. The identification of IL-tolerant enzymes that could be produced as a cellulase cocktail would reduce the costs and water use requirements of the IL pretreatment process. Due to their adaptation to high salinity environments, halophilic enzymes are hypothesized to be good candidates for screening and identifying IL-resistant cellulases. Using a genome-based approach, we have identified and characterized a halophilic cellulase (Hu-CBH1) from the halophilic archaeon, Halorhabdus utahensis. Hu-CBH1 is present in a gene cluster containing multiple putative cellulolytic enzymes. Sequence and theoretical structure analysis indicate that Hu-CBH1 is highly enriched with negatively charged acidic amino acids on the surface, which may form a solvation shell that may stabilize the enzyme, through interaction with salt ions and/or water molecules. Hu-CBH1 is a heat tolerant haloalkaliphilic cellulase and is active in salt concentrations up to 5 M NaCl. In high salt buffer, Hu-CBH1 can tolerate alkali (pH 11.5) conditions and, more importantly, is tolerant to high levels (20percent w/w) of ILs, …
Date: February 17, 2011
Creator: Zhang, Tao; Datta, Supratim; Eichler, Jerry; Ivanova, Natalia; Axen, Seth D.; Kerfeld, Cheryl A. et al.
System: The UNT Digital Library
Mask roughness induced LER: geometric model at long correlation lengths (open access)

Mask roughness induced LER: geometric model at long correlation lengths

Collective understanding of how both the resist and line-edge roughness (LER) on the mask affect the final printed LER has made significant advances. What is poorly understood, however, is the extent to which mask surface roughness couples to image plane LER as a function of illumination conditions, NA, and defocus. Recently, progress has been made in formulating a simplified solution for mask roughness induced LER. Here, we investigate the LER behavior at long correlation lengths of surface roughness on the mask. We find that for correlation lengths greater than 3/NA in wafer dimensions and CDs greater than approximately 0.75/NA, the previously described simplified model, which remains based on physical optics, converges to a 'geometric regime' which is based on ray optics and is independent of partial coherence. In this 'geometric regime', the LER is proportional to the mask slope error as it propagates through focus, and provides a faster alternative to calculating LER in contrast to either full 2D aerial image simulation modeling or the newly proposed physical optics model. Data is presented for both an NA = 0.32 and an NA = 0.5 imaging system for CDs of 22-nm and 50-nm horizontal-line-dense structures.
Date: February 11, 2011
Creator: McClinton, Brittany M. & Naulleau, Patrick P.
System: The UNT Digital Library
Aspen Winter Conferences on High Energy (open access)

Aspen Winter Conferences on High Energy

The 2011 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 12 to February 18, 2011. Ninety-four participants from ten countries, and several universities and national labs attended the workshop titled, �New Data From the Energy Frontier.� There were 54 formal talks, and a considerable number of informal discussions held during the week. The week�s events included a public lecture (�The Hunt for the Elusive Higgs Boson� given by Ben Kilminster from Ohio State University) and attended by 119 members of the public, and a physics caf� geared for high schoolers that is a discussion with physicists. The 2011 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was �Indirect and Direct Detection of Dark Matter.� It was held from February 6 to February 12, 2011. The 70 participants came from 7 countries and attended 53 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists from other institutions and countries or due to incipient collaborations. In addition, Blas Cabrera of …
Date: February 12, 2011
Creator: multiple speakers, presenters listed on link below
System: The UNT Digital Library
Detailed Chemical Kinetic Model for H2 and H2/CO (Syngas) Mixtures at Elevated Pressure (open access)

Detailed Chemical Kinetic Model for H2 and H2/CO (Syngas) Mixtures at Elevated Pressure

None
Date: February 4, 2011
Creator: Keromnes, A; Metcalfe, W K; Donohoe, N; Curran, H J & Pitz, W J
System: The UNT Digital Library
In situ optimization of co-implantation and substrate temperature conditions for Nv-center formation in single crystal diamonds (open access)

In situ optimization of co-implantation and substrate temperature conditions for Nv-center formation in single crystal diamonds

We present first results from in situ characterization of NV-formation in single crystal diamonds following implantation of low energy nitrogen ions (7.7 keV), co-implantation of hydrogen, helium and carbon ions and in situ annealing. Diamond samples were implanted at room temperature or at a temperature of 780{degree} C during the implantation steps. We find that dynamic annealing during co-implantation enhances NV-center formation by up to 25%.
Date: February 1, 2011
Creator: Schwartz, Julian; Michaelides, Philip; Weis, Christoph D. & Schenkel, Thomas
System: The UNT Digital Library
In situ optimization of co-implantation and substrate temperature conditions for Nitrogen-Vacancy center formation in single crystal diamonds (open access)

In situ optimization of co-implantation and substrate temperature conditions for Nitrogen-Vacancy center formation in single crystal diamonds

None
Date: February 11, 2011
Creator: Schwartz, J.; Michaelides, P.; Weis, C. D. & Schenkel, T.
System: The UNT Digital Library
Welcome to Greenhouse Gases: Science and Technology: Editorial (open access)

Welcome to Greenhouse Gases: Science and Technology: Editorial

This editorial introduces readers and contributors to a new online journal. Through the publication of articles ranging from peer-reviewed research papers and short communications, to editorials and interviews on greenhouse gas emissions science and technology, this journal will disseminate research results and information that address the global crisis of anthropogenic climate change. The scope of the journal includes the full spectrum of research areas from capture and separation of greenhouse gases from flue gases and ambient air, to beneficial utilization, and to sequestration in deep geologic formations and terrestrial (plant and soil) systems, as well as policy and technoeconomic analyses of these approaches.
Date: February 1, 2011
Creator: Oldenburg, C. M. & Maroto-Valer, M. M.
System: The UNT Digital Library
Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction (open access)

Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction

None
Date: February 7, 2011
Creator: Lu, T; Plomer, M; Luo, Z; Sarathy, S M; Pitz, W J; Som, S et al.
System: The UNT Digital Library
OpenADR Open Source Toolkit: Developing Open Source Software for the Smart Grid (open access)

OpenADR Open Source Toolkit: Developing Open Source Software for the Smart Grid

Demand response (DR) is becoming an increasingly important part of power grid planning and operation. The advent of the Smart Grid, which mandates its use, further motivates selection and development of suitable software protocols to enable DR functionality. The OpenADR protocol has been developed and is being standardized to serve this goal. We believe that the development of a distributable, open source implementation of OpenADR will benefit this effort and motivate critical evaluation of its capabilities, by the wider community, for providing wide-scale DR services
Date: February 1, 2011
Creator: McParland, Charles
System: The UNT Digital Library
A turbulent transport network model in MULTIFLUX coupled with TOUGH2 (open access)

A turbulent transport network model in MULTIFLUX coupled with TOUGH2

A new numerical method is described for the fully iterated, conjugate solution of two discrete submodels, involving (a) a transport network model for heat, moisture, and airflows in a high-permeability, air-filled cavity; and (b) a variably saturated fractured porous medium. The transport network submodel is an integrated-parameter, computational fluid dynamics solver, describing the thermal-hydrologic transport processes in the flow channel system of the cavity with laminar or turbulent flow and convective heat and mass transport, using MULTIFLUX. The porous medium submodel, using TOUGH2, is a solver for the heat and mass transport in the fractured rock mass. The new model solution extends the application fields of TOUGH2 by integrating it with turbulent flow and transport in a discrete flow network system. We present demonstrational results for a nuclear waste repository application at Yucca Mountain with the most realistic model assumptions and input parameters including the geometrical layout of the nuclear spent fuel and waste with variable heat load for the individual containers. The MULTIFLUX and TOUGH2 model elements are fully iterated, applying a programmed reprocessing of the Numerical Transport Code Functionalization model-element in an automated Outside Balance Iteration loop. The natural, convective airflow field and the heat and mass transport …
Date: February 15, 2011
Creator: Danko, G.; Bahrami, D. & Birkholzer, J.T.
System: The UNT Digital Library
Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater (open access)

Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater

To evaluate the efficacy of bioimmobilization of Cr(VI) in groundwater at the Department of Energy Hanford site, we conducted a series of microcosm experiments using a range of commercial electron donors with varying degrees of lactate polymerization (polylactate). These experiments were conducted using Hanford Formation sediments (coarse sand and gravel) immersed in Hanford groundwater, which were amended with Cr(VI) and several types of lactate-based electron donors (Hydrogen Release Compound, HRC; primer-HRC, pHRC; extended release HRC) and the polylactate-cysteine form (Metal Remediation Compound, MRC). The results showed that polylactate compounds stimulated an increase in bacterial biomass and activity to a greater extent than sodium lactate when applied at equivalent carbon concentrations. At the same time, concentrations of headspace hydrogen and methane increased and correlated with changes in the microbial community structure. Enrichment of Pseudomonas spp. occurred with all lactate additions, and enrichment of sulfate-reducing Desulfosporosinus spp. occurred with almost complete sulfate reduction. The results of these experiments demonstrate that amendment with the pHRC and MRC forms result in effective removal of Cr(VI) from solution most likely by both direct (enzymatic) and indirect (microbially generated reductant) mechanisms.
Date: February 15, 2011
Creator: Brodie, E. L.; Joyner, D. C.; Faybishenko, B.; Conrad, M. E.; Rios-Velazquez, C.; Mork, B. et al.
System: The UNT Digital Library
Topological Cacti: Visualizing Contour-based Statistics (open access)

Topological Cacti: Visualizing Contour-based Statistics

None
Date: February 2, 2011
Creator: Weber, G.; Bremer, P. T. & Pascucci, V.
System: The UNT Digital Library
The ecoresponsive genome of Daphnia pulex (open access)

The ecoresponsive genome of Daphnia pulex

This document provides supporting material related to the sequencing of the ecoresponsive genome of Daphnia pulex. This material includes information on materials and methods and supporting text, as well as supplemental figures, tables, and references. The coverage of materials and methods addresses genome sequence, assembly, and mapping to chromosomes, gene inventory, attributes of a compact genome, the origin and preservation of Daphnia pulex genes, implications of Daphnia's genome structure, evolutionary diversification of duplicated genes, functional significance of expanded gene families, and ecoresponsive genes. Supporting text covers chromosome studies, gene homology among Daphnia genomes, micro-RNA and transposable elements and the 46 Daphnia pulex opsins. 36 figures, 50 tables, 183 references.
Date: February 4, 2011
Creator: Colbourne, John K.; Pfrender, Michael E.; Gilbert, Donald; Thomas, W. Kelley; Tucker, Abraham; Oakley, Todd H. et al.
System: The UNT Digital Library
Phase Preference by Active, Acetate-Utilizing Bacteria at the Rifle, CO Integrated Field Research Challenge Site (open access)

Phase Preference by Active, Acetate-Utilizing Bacteria at the Rifle, CO Integrated Field Research Challenge Site

Previous experiments at the Rifle, Colorado Integrated Field Research Challenge (IFRC) site demonstrated that field-scale addition of acetate to groundwater reduced the ambient soluble uranium concentration. In this report, sediment samples collected before and after acetate field addition were used to assess the active microbes via {sup 13}C acetate stable isotope probing on 3 phases [coarse sand, fines (8-approximately 150 {micro}m), groundwater (0.2-8 {micro}m)] over a 24-day time frame. TRFLP results generally indicated a stronger signal in {sup 13}C-DNA in the 'fines' fraction compared to the sand and groundwater. Before the field-scale acetate addition, a Geobacter-like group primarily synthesized {sup 13}C-DNA in the groundwater phase, an alpha Proteobacterium primarily grew on the fines/sands, and an Acinetobacter sp. and Decholoromonas-like OTU utilized much of the {sup 13}C acetate in both groundwater and particle-associated phases. At the termination of the field-scale acetate addition, the Geobacter-like species was active on the solid phases rather than the groundwater, while the other bacterial groups had very reduced newly synthesized DNA signal. These findings will help to delineate the acetate utilization patterns of bacteria in the field and can lead to improved methods for stimulating distinct microbial populations in situ.
Date: February 21, 2011
Creator: Kerkhof, L.; Williams, K.H.; Long, P.E. & McGuinness, L.
System: The UNT Digital Library
Enhanced topology-sensitive clustering by Reeb graph shattering (open access)

Enhanced topology-sensitive clustering by Reeb graph shattering

None
Date: February 1, 2011
Creator: Harvey, W.; Ruebel, O.; Pascucci, V.; Bremer, P. T. & Wang, Y.
System: The UNT Digital Library