Repositioning the Essential Art in Collaborative Technology-Mediated Design Education

Asserting the responsiveness of integrated design processesto the human condition relies upon these processes being informedby an artistic tradition founded in cognitive activities that are motivatedby the conceiving of unique environmental form. This paper examines the changing, yet essential role of creative activities in contemporary project delivery systems within the context of an ideal business construct,the Virtual Organization. The implications of this transformationfor project-based design studio synthetic experience-contingent learningare discussed with reference to an ideal pedagogical construct,the Virtual Design Studio. Because the latter represents learning experiences that are predicated on its empirical counterpart, the Virtual Organization, pedagogical dimensions appropriate to learning strategiesin collaborative technology-mediated environments are explicated

Multi-Cone Model for Estimating GPS Ionospheric Delays

The multi-cone model is a computational model for estimating ionospheric delays of Global Positioning System (GPS) signals. It is a direct descendant of the conical-domain model. A primary motivation for the development of this model is the need to find alternatives for modeling slant delays at low latitudes, where ionospheric behavior poses an acute challenge for GPS signal-delay estimates based upon the thin-shell model of the ionosphere

Generating high precision ionospheric ground-truth measurements

A method, apparatus and article of manufacture provide ionospheric ground-truth measurements for use in a wide-area augmentation system (WAAS). Ionospheric pseudorange/code and carrier phase data as primary observables is received by a WAAS receiver. A polynomial fit is performed on the phase data that is examined to identify any cycle slips in the phase data. The phase data is then leveled. Satellite and receiver biases are obtained and applied to the leveled phase data to obtain unbiased phase-leveled ionospheric measurements that are used in a WAAS system. In addition, one of several measurements may be selected and data is output that provides information on the quality of the measurements that are used to determine corrective messages as part of the WAAS system

Proteomic analysis of the fish pathogen Flavobacterium columnare

<p>Abstract</p> <p>Background</p> <p><it>Flavobacterium columnare </it>causes columnaris disease in cultured and wild fish populations worldwide. Columnaris is the second most prevalent bacterial disease of commercial channel catfish industry in the United States. Despite its economic importance, little is known about the expressed proteins and virulence mechanisms of <it>F. columnare</it>. Here, we report the first high throughput proteomic analysis of <it>F. columnare </it>using 2-D LC ESI MS/MS and 2-DE MALDI TOF/TOF MS.</p> <p>Results</p> <p>Proteins identified in this study and predicted from the draft <it>F. columnare </it>genome were clustered into functional groups using clusters of orthologous groups (COGs), and their subcellular locations were predicted. Possible functional relations among the identified proteins were determined using pathway analysis. The total number of unique <it>F. columnare </it>proteins identified using both 2-D LC and 2-DE approaches was 621, of which 10.95% (68) were identified by both methods, while 77.29% (480) and 11.76% (73) were unique in 2-D LC and 2-DE, respectively. COG groupings and subcellular localizations were similar between our data set and proteins predicted from the whole genome. Twenty eight pathways were significantly represented in our dataset (<it>P </it>< 0.05).</p> <p>Conclusion</p> <p>Results from this study provide experimental evidence for many proteins that were predicted from the <it>F. columnare </it>genome annotation, and they should accelerate functional and comparative studies aimed at understanding virulence mechanisms of this important pathogen.</p

Development of stable reporter system cloning luxCDABE genes into chromosome of Salmonella enterica serotypes using Tn7 transposon

<p>Abstract</p> <p>Background</p> <p>Salmonellosis may be a food safety problem when raw food products are mishandled and not fully cooked. In previous work, we developed bioluminescent <it>Salmonella enterica </it>serotypes using a plasmid-based reporting system that can be used for real-time monitoring of the pathogen's growth on food products in short term studies. In this study, we report the use of a Tn7-based transposon system for subcloning of <it>luxCDABE </it>genes into the chromosome of eleven <it>Salmonella enterica </it>serotypes isolated from the broiler production continuum.</p> <p>Results</p> <p>We found that the <it>lux </it>operon is constitutively expressed from the chromosome post-transposition and the <it>lux </it>cassette is stable without external pressure, i.e. antibiotic selection, for all <it>Salmonella enterica </it>serotypes used. Bioluminescence expression is based on an active electron transport chain and is directly related with metabolic activity. This relationship was quantified by measuring bioluminescence against a temperature gradient in aqueous solution using a luminometer. In addition, bioluminescent monitoring of two serotypes confirmed that our chicken skin model has the potential to be used to evaluate pathogen mitigation strategies.</p> <p>Conclusions</p> <p>This study demonstrated that our new stable reporting system eliminates bioluminescence variation due to plasmid instability and provides a reliable real-time experimental system to study application of preventive measures for <it>Salmonella </it>on food products in real-time for both short and long term studies.</p

Comparative Genomics of Aeromonas hydrophila Secretion Systems and Mutational Analysis of hcp1 and vgrG1 Genes From T6SS

Virulent Aeromonas hydrophila causes severe motile Aeromonas septicemia in warmwater fishes. In recent years, channel catfish farming in the U.S.A. and carp farming in China have been affected by virulent A. hydrophila, and genome comparisons revealed that these virulent A. hydrophila strains belong to the same clonal group. Bacterial secretion systems are often important virulence factors; in the current study, we investigated whether secretion systems contribute to the virulent phenotype of these strains. Thus, we conducted comparative secretion system analysis using 55 A. hydrophila genomes, including virulent A. hydrophila strains from U.S.A. and China. Interestingly, tight adherence (TaD) system is consistently encoded in all the vAh strains. The majority of U.S.A. isolates do not possess a complete type VI secretion system, but three core elements [tssD (hcp), tssH, and tssI (vgrG)] are encoded. On the other hand, Chinese isolates have a complete type VI secretion system operon. None of the virulent A. hydrophila isolates have a type III secretion system. Deletion of two genes encoding type VI secretion system proteins (hcp1 and vgrG1) from virulent A. hydrophila isolate ML09-119 reduced virulence 2.24-fold in catfish fingerlings compared to the parent strain ML09-119. By determining the distribution of genes encoding secretion systems in A. hydrophila strains, our study clarifies which systems may contribute to core A. hydrophila functions and which may contribute to more specialized adaptations such as virulence. Our study also clarifies the role of type VI secretion system in A. hydrophila virulence

Universal Stress Proteins Contribute Edwardsiella ictaluri Virulence in Catfish

Edwardsiella ictaluri is an intracellular Gram-negative facultative pathogen causing enteric septicemia of catfish (ESC), a common disease resulting in substantial economic losses in the U.S. catfish industry. Previously, we demonstrated that several universal stress proteins (USPs) are highly expressed under in vitro and in vivo stress conditions, indicating their importance for E. ictaluri survival. However, the roles of these USPs in E. ictaluri virulence is not known yet. In this work, 10 usp genes of E. ictaluri were in-frame deleted and characterized in vitro and in vivo. Results show that all USP mutants were sensitive to acidic condition (pH 5.5), and EiΔusp05 and EiΔusp08 were very sensitive to oxidative stress (0.1% H2O2). Virulence studies indicated that EiΔusp05, EiΔusp07, EiΔusp08, EiΔusp09, EiΔusp10, and EiΔusp13 were attenuated significantly compared to E. ictaluri wild-type (EiWT; 20, 45, 20, 20, 55, and 10% vs. 74.1% mortality, respectively). Efficacy experiments showed that vaccination of catfish fingerlings with EiΔusp05, EiΔusp07, EiΔusp08, EiΔusp09, EiΔusp10, and EiΔusp13 provided complete protection against EiWT compared to sham-vaccinated fish (0% vs. 58.33% mortality). Our results support that USPs contribute E. ictaluri virulence in catfish

Taxonomic and Functional Metagenomic Profile of Sediment From a Commercial Catfish Pond in Mississippi

Metagenomic analyses of microbial communities from aquatic sediments are relatively few, and there are no reported metagenomic studies on sediment from inland ponds used for aquaculture. Catfish ponds in the southeastern U.S. are eutrophic systems. They are fertilized to enhance algae growth and encourage natural food production, and catfish are fed with commercial feed from spring to fall. As result, catfish pond sediment (CPS) contains a very dense, diverse microbial community that has significant effects on the physiochemical parameters of pond dynamics. Here we conducted an in-depth metagenomic analysis of the taxonomic and metabolic capabilities of a catfish pond sediment microbiome from a southeastern U.S. aquaculture farm in Mississippi using Illumina next-generation sequencing. A total of 3.3 Gbp of sequence was obtained, 25,491,518 of which encoded predicted protein features. The pond sediment was dominated by Proteobacteria sequences, followed by Bacteroidetes, Firmicutes, Chloroflexi, and Actinobacteria. Enzyme pathways for methane metabolism/methanogenesis, denitrification, and sulfate reduction appeared nearly complete in the pond sediment metagenome profile. In particular, a large number of Deltaproteobacteria sequences and genes encoding anaerobic functional enzymes were found. This is the first study to characterize a catfish pond sediment microbiome, and it is expected to be useful for characterizing specific changes in microbial flora in response to production practices. It will also provide insight into the taxonomic diversity and metabolic capabilities of microbial communities in aquaculture. Furthermore, comparison with other environments (i.e., river and marine sediments) will reveal habitat-specific characteristics and adaptations caused by differences in nutrients, vegetation, and environmental stresses

Diclofenac Prolongs Repolarization in Ventricular Muscle with Impaired Repolarization Reserve

Background: The aim of the present work was to characterize the electrophysiological effects of the non-steroidal anti- inflammatory drug diclofenac and to study the possible proarrhythmic potency of the drug in ventricular muscle. Methods: Ion currents were recorded using voltage clamp technique in canine single ventricular cells and action potentials were obtained from canine ventricular preparations using microelectrodes. The proarrhythmic potency of the drug was investigated in an anaesthetized rabbit proarrhythmia model. Results: Action potentials were slightly lengthened in ventricular muscle but were shortened in Purkinje fibers by diclofenac (20 mM). The maximum upstroke velocity was decreased in both preparations. Larger repolarization prolongation was observed when repolarization reserve was impaired by previous BaCl 2 application. Diclofenac (3 mg/kg) did not prolong while dofetilide (25 mg/kg) significantly lengthened the QT c interval in anaesthetized rabbits. The addition of diclofenac following reduction of repolarization reserve by dofetilide further prolonged QT c . Diclofenac alone did not induce Torsades de Pointes ventricular tachycardia (TdP) while TdP incidence following dofetilide was 20%. However, the combination of diclofenac and dofetilide significantly increased TdP incidence (62%). In single ventricular cells diclofenac (30 mM) decreased the amplitude of rapid (I Kr ) and slow (I Ks ) delayed rectifier currents thereby attenuating repolarization reserve. L-type calcium current (I Ca ) was slightly diminished, but the transient outward (I to ) and inward rectifier (I K1 ) potassium currents were not influenced. Conclusions: Diclofenac at therapeutic concentrations and even at high dose does not prolong repolarization markedly and does not increase the risk of arrhythmia in normal heart. However, high dose diclofenac treatment may lengthen repolarization and enhance proarrhythmic risk in hearts with reduced repolarization reserve