Oak Ridge National Laboratory

About: Oak Ridge National Laboratory is a facility organization based out in Oak Ridge, Tennessee, United States. It is known for research contribution in the topics: Neutron & Ion. The organization has 31868 authors who have published 73724 publications receiving 2633689 citations. The organization is also known as: ORNL.

Integrated Metagenomics/Metaproteomics Reveals Human Host-Microbiota Signatures of Crohn's Disease

Abstract: Crohn's disease (CD) is an inflammatory bowel disease of complex etiology, although dysbiosis of the gut microbiota has been implicated in chronic immune-mediated inflammation associated with CD. Here we combined shotgun metagenomic and metaproteomic approaches to identify potential functional signatures of CD in stool samples from six twin pairs that were either healthy, or that had CD in the ileum (ICD) or colon (CCD). Integration of these omics approaches revealed several genes, proteins, and pathways that primarily differentiated ICD from healthy subjects, including depletion of many proteins in ICD. In addition, the ICD phenotype was associated with alterations in bacterial carbohydrate metabolism, bacterial-host interactions, as well as human host-secreted enzymes. This eco-systems biology approach underscores the link between the gut microbiota and functional alterations in the pathophysiology of Crohn's disease and aids in identification of novel diagnostic targets and disease specific biomarkers.

Intranuclear-cascade calculation of the secondary nucleon spectra from nucleon-nucleus interactions in the energy range 340 to 2900 mev and comparisons with experiment

Abstract: Total nonelastic cross sections and the nucleon spectra fron continuum-state transitions for protons on complex nuclei are calculated using the intranuclear-cascade approach. Comparisons with experiment are made over the energy range 340-2900 MeV. The diffuseness of the nuclear surface, the energy distribution of the bound nucleons, and the exclusion principle are taken into account in the model of the nucleus, while experimentally determined free-particle elastic, inelastic, and differential cross sections are utilized in the calculation of the particle-particle reactions assumed to take place inside the nucleus. The Sternheimer-Lindenbaum isobar model is used in describing all pion-production processes. All but two of the comparisons with experiment are made on an absolute basis. The theoretical nonelastic cross sections and the theoretical secondary-particle spectra resulting from continuum-state transitions are shown to be in reasonable agreement with experimental data over the broad energy range considered. The effect of pion production and the effect of the diffuse nuclear boundary are illustrated for a few cases. The quasifree peak is shown to be dominated by single-scattering events that take place inside the nucleus.

Electroactive biofilms: Current status and future research needs

Abstract: Electroactive biofilms (EABFs) generated by electrochemically active microorganisms have many potential applications in bioenergy and chemicals production. Biofilm electroactivity can have a significant impact on the yield and efficiency of the conversion processes. This review assesses the effects of process and design parameters on the growth and activity of biofilms in bioelectrochemical systems (BESs). First we compare the role of planktonic and biofilm-forming microorganisms in BESs. The effect of physical, chemical, and electrochemical operating parameters such as flow rate, temperature, pH, ionic strength, substrate concentration and loading, external resistance, and redox potential on EABF attributes such as growth rate, exoelectrogen population, formation of extracellular polymeric substances, mediator synthesis, and rate of electron transfer are discussed. The relationship between electrochemical performance and operating parameters is also examined to identify gaps in assessment and the potential role of future modeling efforts. Similarly, we review what is currently known about the mechanisms that enable electroactive biofilms to transfer electrons and also the contribution of the electrical conductivity of the biofilms' exopolymeric components to BES performance. The current status of cathodic biofilms is also reviewed. Complementary approaches that use process control to optimize EABF composition and biomass density, while minimizing mass transfer effects and changes to system design parameters, are likely necessary to improve BES performance to a level needed for commercial consideration. Finally, future research needs that enable better understanding and optimization of the performance of EABFs are outlined.

Candidate gene associated with a mutation causing recessive polycystic kidney disease in mice

Abstract: A line of transgenic mice was generated that contains an insertional mutation causing a phenotype similar to human autosomal recessive polycystic kidney disease. Homozygotes displayed a complex phenotype that included bilateral polycystic kidneys and an unusual liver lesion. The mutant locus was cloned and characterized through use of the transgene as a molecular marker. Additionally, a candidate polycystic kidney disease (PKD) gene was identified whose structure and expression are directly associated with the mutant locus. A complementary DNA derived from this gene predicted a peptide containing a motif that was originally identified in several genes involved in cell cycle control.

Optimal stomatal behaviour around the world

Abstract: Stomatal conductance (g(s)) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of g(s) in predictions of global water and carbon cycle changes, a global-scale database and an associated globally applicable model of g(s) that allow predictions of stomatal behaviour are lacking. Here, we present a database of globally distributed g(s) obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model(1) and the leaf and wood economics spectrum(2,3). We also demonstrate a global relationship with climate. These findin g(s) provide a robust theoretical framework for understanding and predicting the behaviour of g(s) across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.