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Search Results: 1 - 10 of 307588 matches for " Timothy J Young "
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A Gigantic Sarcopterygian (Tetrapodomorph Lobe-Finned Fish) from the Upper Devonian of Gondwana (Eden, New South Wales, Australia)
Ben Young, Robert L. Dunstone, Timothy J. Senden, Gavin C. Young
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053871
Abstract: Edenopteron keithcrooki gen. et sp. nov. is described from the Famennian Worange Point Formation; the holotype is amongst the largest tristichopterids and sarcopterygians documented by semi-articulated remains from the Devonian Period. The new taxon has dentary fangs and premaxillary tusks, features assumed to be derived for large Northern Hemisphere tristichopterids (Eusthenodon, Hyneria, Langlieria). It resembles Eusthenodon in ornament, but is distinguished by longer proportions of the parietal compared to the post-parietal shield, and numerous differences in shape and proportions of other bones. Several characters (accessory vomers in the palate, submandibulars overlapping ventral jaw margin, scales ornamented with widely-spaced deep grooves) are recorded only in tristichopterids from East Gondwana (Australia-Antarctica). On this evidence Edenopteron gen. nov. is placed in an endemic Gondwanan subfamily Mandageriinae within the Tristichopteridae; it differs from the nominal genotype Mandageria in its larger size, less pointed skull, shape of the orbits and other skull characters. The hypothesis that tristichopterids evolved in Laurussia and later dispersed into Gondwana, and a derived subgroup of large Late Devonian genera dispersed from Gondwana, is inconsistent with the evidence of the new taxon. Using oldest fossil and most primitive clade criteria the most recent phylogeny resolves South China and Gondwana as areas of origin for all tetrapodomorphs. The immediate outgroup to tristichopterids remains unresolved – either Spodichthys from Greenland as recently proposed, or Marsdenichthys from Gondwana, earlier suggested to be the sister group to all tristichopterids. Both taxa combine two characters that do not co-occur in other tetrapodomorphs (extratemporal bone in the skull; non-cosmoid round scales with an internal boss). Recently both ‘primitive’ and ‘derived’ tristichopterids have been discovered in the late Middle Devonian of both hemispheres, implying extensive ghost lineages within the group. Resolving their phylogeny and biogeography will depend on a comprehensive new phylogenetic analysis.
Comparison of Mycobacterium tuberculosis Genomes Reveals Frequent Deletions in a 20 kb Variable Region in Clinical Isolates
Timothy B. L. Ho,Brian D. Robertson,G. Michael Taylor,Rory J. Shaw,Douglas B. Young
Comparative and Functional Genomics , 2000, DOI: 10.1002/1097-0061(200012)17:4<272::aid-yea48>3.0.co;2-2
Abstract: The Mycobacterium tuberculosis complex is associated with a remarkably low level of structural gene polymorphism. As part of a search for alternative forms of genetic variation that may act as a source of biological diversity in M. tuberculosis, we have identified a region of the genome that is highly variable amongst a panel of unrelated clinical isolates. Fifteen of 24 isolates examined contained one or more copies of the M. tuberculosis-specific IS6110 insertion element within this 20 kb variable region. In nine of the isolates, including the laboratory-passaged strain H37Rv, genomic deletions were identified, resulting in loss of between two and 13 genes. In each case, deletions were associated with the presence of a copy of the IS6110 element. Absence of flanking tri- or tetra-nucleotide repeats identified homologous recombination between adjacent IS6110 elements as the most likely mechanism of the deletion events. IS6110 insertion into hot-spots within the genome of M. tuberculosis provides a mechanism for generation of genetic diversity involving a high frequency of insertions and deletions.
Molecular and cellular characterization of ABCG2 in the prostate
Laura E Pascal, Asa J Oudes, Timothy W Petersen, Young Goo, Laura S Walashek, Lawrence D True, Alvin Y Liu
BMC Urology , 2007, DOI: 10.1186/1471-2490-7-6
Abstract: Immunolocalization of ABCG2 was performed on normal prostate tissue obtained from radical prostatectomies. Normal human prostate SP cells and ABCG2+ cells were isolated and gene expression was determined with DNA array analysis and RT-PCR. Endothelial cells were removed by pre-sorting with CD31.ABCG2 positive cells were localized to the prostate basal epithelium and endothelium. ABCG2+ cells in the basal epithelium constituted less than 1% of the total basal cell population. SP cells constituted 0.5–3% of the total epithelial fraction. The SP transcriptome was essentially the same as ABCG2+ and both populations expressed genes indicative of a stem cell phenotype, however, the cells also expressed many genes in common with endothelial cells.These results provide gene expression profiles for the prostate SP and ABCG2+ cells that will be critical for studying normal development and carcinogenesis, in particular as related to the cancer stem cell concept.Experimental evidence suggests that prostatic epithelial stem cells exist and are likely localized to the basal epithelium [1]. Basal, luminal secretory and a small population of neuroendocrine cells constitute the epithelial component of prostatic acini. Basal and luminal cells may belong to two functional cell types descended from a common stem cell type. We are interested in identifying and isolating this prostatic stem cell. Studies to date suggest that stem cells from diverse tissue sources may contain a common set of gene transcripts, which are required for maintenance of the stem cell phenotype [2]. Considerable research efforts have been directed towards discovery of markers associated with the putative prostate stem cell, including the side population (SP) phenotype [3], integrin α2β1 (CD49b/CD29) [4,5] and PROM1 (CD133) [6]. Identification and characterization of a stem/progenitor cell population is important to our understanding of not only normal prostate development but also the cancer process, particularly
Statistical Properties of Blue Horizontal Branch Stars in the Spheroid: Detection of a Moving Group approximately 50 kpc from the Sun
Matthew J. Harrigan,Heidi Jo Newberg,Lee A. Newberg,Brian Yanny,Timothy C. Beers,Young Sun Lee,Paola Re Fiorentin
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.16552.x
Abstract: A new moving group comprising at least four Blue Horizontal Branch (BHB) stars is identified at (l,b) = (65 deg, 48 deg). The horizontal branch at g0=18.9 magnitude implies a distance of 50 kpc from the Sun. The heliocentric radial velocity is RV = -157 +/- 4 km/s, corresponding to V(gsr) = -10 km/s; the dispersion in line-of-sight velocity is consistent with the instrumental errors for these stars. The mean metallicity of the moving group is [Fe/H] approximately -2.4, which is significantly more metal poor than the stellar spheroid. We estimate that the BHB stars in the outer halo have a mean metallicity of [Fe/H] = -2.0, with a wide scatter and a distribution that does not change much as a function of distance from the Sun. We explore the systematics of SDSS DR7 surface gravity metallicity determinations for faint BHB stars, and present a technique for estimating the significance of clumps discovered in multidimensional data. This moving group cannot be distinguished in density, and highlights the need to collect many more spectra of Galactic stars to unravel the merger history of the Galaxy.
Powder River Basin Coal: Powering America  [PDF]
Timothy J. Considine
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.48063
Abstract:

Powder River Basin (PRB) coal in Wyoming and Montana is used to produce 18 percent of the electricity consumed in the United States. Coal production from the PRB more than doubled between 1994 and 2009. PRB coal companies produced greater amounts of coal at declining real prices over much of this period through investment in equipment and production systems that achieved massive economies of scale. The bulk of PRB coal is shipped to the middle part of America from Texas in the south to Michigan in the north and New York in the east. States that consume significant amounts of PRB coal have electricity rates well below the national average. The largest industrial users of electricity are in these regions. Replacing PRB coal would require almost 5.5 trillion cubic feet of natural gas per year, representing a 26 percent increase in demand. Such an increase in gas consumption would increase prices for natural gas by roughly 76 percent. In such a world, U.S. energy users would pay $107 billion more each year for electricity and natural gas. Hence, by using PRB coal, the U.S. economy avoids $107 billion per year in higher energy costs. Estimates reported in the literature indicate that the gross environmental damages from PRB coal production are $27 billion. Hence, the net social benefits of PRB coal are $80 billion per year. Given the large size and low cost of these reserves, PRB coal will likely supply societal energy needs well into the future as long as the public and their elected officials are willing to accept the environmental impacts in return for the substantial economic benefits from using PRB coal.

An Integrative Socio-Technical Enterprise Approach to Urban Design/Planning for Sustainable Development  [PDF]
Timothy J. Downs
Open Journal of Civil Engineering (OJCE) , 2018, DOI: 10.4236/ojce.2018.82015
Abstract: Human society locally and globally needs to better understand and respond to ever-more complex, interwoven problems: environmental degradation; climate instability; persistent poverty; disparities in human health; growing income/wealth inequality; economies and infrastructures vulnerable to climate shock; and mounting socio-political unrest. Cities are where most people live, urbanization is a strong upward global trend, and cities bring all these problems into sharp, compelling focus. Since outcomes stem from processes and systems, we argue transformative changes depend on re-imagining the Urban Design, Urban Planning and Urban Development Practice (UD/UP/UDP) process. While there has been insufficient attention to process innovation— with technological aspects tending to dominate UD/UP/UDP work—emerging systems views of cities, and disenchantment with existing modes are enabling. We propose an empirically based integrative frame to tackle recognized conundrums, and inform an adaptive UD/UP/UDP process—from concept through design, assessment, planning, implementation, project functioning and monitoring. The frame contemplates six domains (6-D): 1) Project ethos, concept, and framing; 2) sectors, topics, and issues; 3) Varying spatial and temporal scales; 4) Stakeholder interests, relationships and capacities; 5) Knowledge types, modes and methods; and 6) Socio-technical capacities and networks. The frame, process and outcomes constitute a socio-technical enterprise (STE) approach to UD/UP/UDP work, with implications for education, training, and professional practice. We highlight the pivotal role Integrators and Universities play, and the scalability of STE knowledge/capacity networks. The case of Greater Mexico City/Central Mexico Urban Region illustrates the utility of the approach in a hyper-complex, climate-change vulnerable regional context.
The Economic Impacts of Restrictions on the Transportation of Petroleum Coke  [PDF]
Timothy J. Considine
Natural Resources (NR) , 2019, DOI: 10.4236/nr.2019.103005
Abstract: Petroleum coke is the?third?leading refined petroleum product export from the US behind distillate fuel oil. Legal challenges and proposals could either increase the cost or restrict the transportation of petroleum coke. This paper develops an econometric model of world markets for refined petroleum markets to estimate the effects of such restrictions. The model is used to estimate how supply, demand, trade flows, and prices would adjust under a shutdown of US petroleum coke production. The market impacts are significant, withsubstantially higher prices for jet fuel and petroleum coke, significantly higher prices for gasoline and other products, and sharply lower prices for residual fuel oil. Over a four-year simulation of the model, the US petroleum trade balance deteriorates by $85 billion and consumers pay over $187 and $376 billion more for refined petroleum products in the US and the rest of the world respectively.
Combined histomorphometric and gene-expression profiling applied to toxicology
Andres Kriete, Mary K Anderson, Brad Love, John Freund, James J Caffrey, M Brook Young, Timothy J Sendera, Scott R Magnuson, J Mark Braughler
Genome Biology , 2003, DOI: 10.1186/gb-2003-4-5-r32
Abstract: Recent reports describe the use of gene-expression profiling for the identification of molecular markers of toxicity [1-3]. This technique alone does not account for morphological changes in tissues that have traditionally been used by pathologists to discriminate between types and severity of toxicological responses [4-6]. For a comprehensive approach to toxicological evaluation, we developed a unique methodology that uses histomorphometric profiles, derived from machine vision, in conjunction with gene-expression profiles, termed extensible morphometric relational gene-expression analysis (EMeRGE). This novel method was evaluated on an established, extreme model of liver toxicity using carbon tetrachloride (CCl4) in rats that were dosed for 3 days and allowed to recover. Liver is relevant in toxicology as the primary organ of metabolism and detoxification; it is a recurrent target of chronic drug toxicity.A fully automated analytical microscope equipped with machine-vision hardware and software was used to generate quantitative information about the structure and heterogeneity of liver. The histomorphometric profiles could be used to evaluate tissue heterogeneity across the tissue including regions of hepatocellular necrosis. Representative images of tissue sections from control and treated tissues are shown in Figure 1. Examples of processed sample image tiles are shown in Figure 2, where a control liver (Figure 2a) can be compared to a treated liver (Figure 2b), illustrating the significant structural damage induced by treatment with CCl4. Gene-expression profiles were generated from the same livers using DNA microarrays. The microarrays measured mRNA transcription levels of genes important in adsorption, distribution, metabolism and excretion (ADME). Previous studies of these genes, including markers of toxic stress, apoptosis, growth regulation and repair, were consistent with documented toxicologic responses to CCl4, where expression of components of cytochro
Cutaneous nociception evoked by 15-delta PGJ2 via activation of ion channel TRPA1
Lillian Cruz-Orengo, Ajay Dhaka, Robert J Heuermann, Timothy J Young, Michael C Montana, Eric J Cavanaugh, Donghee Kim, Gina M Story
Molecular Pain , 2008, DOI: 10.1186/1744-8069-4-30
Abstract: Our search for endogenous chemical activators utilizing a bioactive lipid library screen identified a cyclopentane PGD2 metabolite, 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), as a TRPA1 agonist. Similar to CA and AITC, this electrophilic molecule is known to modify cysteines of cellular target proteins. Electophysiological recordings verified that 15d-PGJ2 specifically activates TRPA1 and not TRPV1 or TRPM8 (thermoTRPs also enriched in DRG). Accordingly, we identified a population of mouse DRG neurons responsive to 15d-PGJ2 and AITC that is absent in cultures derived from TRPA1 knockout mice. The irritant molecules that activate TRPA1 evoke nociceptive responses. However, 15d-PGJ2 has not been correlated with painful sensations; rather, it is considered to mediate anti-inflammatory processes via binding to the nuclear peroxisome proliferator-activated receptor gamma (PPARγ). Our in vivo studies revealed that 15d-PGJ2 induced acute nociceptive responses when administered cutaneously. Moreover, mice deficient in the TRPA1 channel failed to exhibit such behaviors.In conclusion, we show that 15d-PGJ2 induces acute nociception when administered cutaneously and does so via a TRPA1-specific mechanism.The prostaglandins (PGs) are a class of biomolecules derived from arachidonic acid (AA) that are involved in a variety of signaling processes including inflammation. For example, PGE2 and PGI2 are produced during inflammation and contribute to the direct sensitization of nociceptive neurons of the dorsal root ganglia (DRG). Downstream of binding to its G protein-coupled receptor (GPCR), PGE2 sensitizes nociceptive neurons to thermal stimuli via PKA-dependent phosphorylation of the heat- and capsaicin-gated Transient Receptor Potential (TRP) ion channel TRPV1 [1]. TRPV1 is the founding mammalian member of a subfamily of TRP channels gated by temperature (dubbed thermoTRPs)[2].TRPA1, first characterized as a thermoTRP channel gated by noxious cold (although this finding is con
Does Aristotle Refute the Harmonia Theory of the Soul?  [PDF]
Douglas J. Young
Open Journal of Philosophy (OJPP) , 2013, DOI: 10.4236/ojpp.2013.31008
Abstract:

In Aristotle’s On the Soul he considers and refutes two versions of the harmonia theory of the soul’s relation to the body. According to the harmonia theory, the soul is to the body what the tuning of a musical instrument is to its material parts. Though he believes himself to have entirely dismissed the view, he has not. I argue that Aristotle’s hylomorphic account is, in fact, an instance of the harmonia theory.

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