Search results for "Lux"
showing 10 items of 1464 documents
C4-dicarboxylate carriers and sensors in bacteria
2002
AbstractBacteria contain secondary carriers for the uptake, exchange or efflux of C4-dicarboxylates. In aerobic bacteria, dicarboxylate transport (Dct)A carriers catalyze uptake of C4-dicarboxylates in a H+- or Na+-C4-dicarboxylate symport. Carriers of the dicarboxylate uptake (Dcu)AB family are used for electroneutral fumarate:succinate antiport which is required in anaerobic fumarate respiration. The DcuC carriers apparently function in succinate efflux during fermentation. The tripartite ATP-independent periplasmic (TRAP) transporter carriers are secondary uptake carriers requiring a periplasmic solute binding protein. For heterologous exchange of C4-dicarboxylates with other carboxylic …
Maintenance Operation on AGN-201 “COSTANZA” Nuclear Research Reactor of Palermo University
2015
During operations with AGN-201 “COSTANZA” nuclear research reactor of Palermo University a failure of a compensated boron-lined ionization chamber provided with a measurement channel was highlighted. A maintenance program aimed to verify the operative conditions of all measurement systems was then started. It was easy to identify as cause of the malfunction a seepage of water inside the container of a Westinghouse WL 6377 ion chamber due to a lack of watertight closure. This can be attributed to corrosion of the container due to parasitic currents circulating between the container, the chamber and the reactor tank that acts as electrical ground of the system. In this work we refer over main…
Earth system data cubes unravel global multivariate dynamics
2020
Understanding Earth system dynamics in light of ongoing human intervention and dependency remains a major scientific challenge. The unprecedented availability of data streams describing different facets of the Earth now offers fundamentally new avenues to address this quest. However, several practical hurdles, especially the lack of data interoperability, limit the joint potential of these data streams. Today, many initiatives within and beyond the Earth system sciences are exploring new approaches to overcome these hurdles and meet the growing interdisciplinary need for data-intensive research; using data cubes is one promising avenue. Here, we introduce the concept of Earth system data cu…
Sometimes less is more—the impact of the number of His residues on the stability of Zn(ii)–SmtB and BigR4 α-5 domain complexes
2021
The increasing number of antibiotic-resistant pathogens has become one of the major health problems of modern times, including infections caused by Mycobacterium tuberculosis. One of the possible mammalian immune system responses to mycobacterial infection is the increase of the zinc(II) concentration in phagosomes to a toxic level. The mycobacterial SmtB protein belongs to the family of ArsR/SmtB transcription regulators. In the presence of high concentrations of metals, SmtB dissociates from DNA and activates the expression of metal efflux proteins. In this work, we focus on the α5 zinc(II) binding domains of SmtB/BigR4 proteins (the latter being the SmtB homolog from non-pathogenic M. sm…
685 Food Allergy - Gastro-Esophageal Reflux Disease Association in Infants
2012
Background Cow’s milk allergy is considered to be the first and most common type of allergy during early infancy. Gastro-esophageal reflux disease and cow’s milk allergy are two different diseases with common clinical features. The aim of the study was to evaluate the clinical data in relation with gastroesophageal reflux and cow’s milk allergy in infants. Material and Methods The prospective study includes 36 infants aged between 2–6 months who attended at Pediatric Clinic during the year 2011 for the clinical evocative manifestations of gastroesophageal reflux. Study protocol includes: clinical criteria, familial/personal atopic features, mother diet, duration of breastfeeding, infant for…
Les ambroisies annuelles (Ambrosia artemisiifolia et Ambrosia trifida) : réponse adaptative au désherbage chimique et connectivité des populations da…
2018
The primary aim of this work was to study the risk of resistance evolution to acetolactate synthase (ALS) inhibiting herbicides in mugwort (Ambrosia artemisiifolia L.) through four points: (i) selection pressure (study of the efficacy of a range of ALS-inhibiting herbicides), (ii) the adaptive response capacity of the weed (determination of the variation in sensitivity to ALS inhibitors between plants and implementation of a recurrent selection programme), (iii) a field study (search for resistance to ALS inhibitors in the field in France), (iv) the study of resistance mechanisms (target-linked - TLR - and non-target-linked - NLR - by a transcriptomics approach). The second objective was to…
Alternative respiratory pathways of Escherichia coli: energetics and transcriptional regulation in response to electron acceptors
1997
AbstractThe electron-transport chains of Escherichia coli are composed of many different dehydrogenases and terminal reductases (or oxidases) which are linked by quinones (ubiquinone, menaquinone and demethylmenaquinone). Quinol:cytochrome c oxido-reductase (`bc1 complex') is not present. For various electron acceptors (O2, nitrate) and donors (formate, H2, NADH, glycerol-3-P) isoenzymes are present. The enzymes show great variability in membrane topology and energy conservation. Energy is conserved by conformational proton pumps, or by arrangement of substrate sites on opposite sides of the membrane resulting in charge separation. Depending on the enzymes and isoenzymes used, the H+/e− rat…
Biologically labile photoproducts from riverine non-labile dissolved organic carbon in the coastal waters
2015
In order to assess the production of biologically labile photoproducts (BLPs) from non-labile riverine dissolved organic carbon (DOC), we collected water samples from ten major rivers, removed labile DOC and mixed the residual non-labile DOC with artificial seawater for microbial and photochemical experiments. Bacteria grew on non-labile DOC with a growth efficiency of 11.5% (mean; range from 3.6 to 15.3%). Simulated solar radiation transformed a part of non-labile DOC into BLPs, which stimulated bacterial respiration and production, but did not change bacterial growth efficiency (BGE) compared to the non-irradiated dark controls. In the irradiated water samples, the amount of BLPs stimulat…
Dimensionless Analysis Of Slurry Photocatalytic Reactors Using Two-Flux And Six-Flux Radiation Absorption-Scattering Models
2007
Photocatalytic oxidation (PCO) over titanium dioxide (TiO2) is a "green" sustainable process for the treatment and purification of water and wastewater. However,the application of PCO for wastewater treatment on an industrial scale is currently hindered by a lack of simple mathematical models that can be readily applied to reactor design. Current models are either too simplistic or too rigorous to be useful in photocatalytic reactor design, scale-up, and optimization. In this paper a simple mathematical model is presented for slurry, annular, photocatalytic reactors that still retains the essential elements of a rigorous approach while providing simple solutions. The model extends the appli…
The search for Muon neutrinos from northern hemisphere gamma-ray bursts with AMANDA
2007
We present the results of the analysis of neutrino observations by the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated with photon observations of more than 400 gamma-ray bursts (GRBs) in the Northern Hemisphere from 1997 to 2003. During this time period, AMANDA's effective collection area for muon neutrinos was larger than that of any other existing detector. Based on our observations of zero neutrinos during and immediately prior to the GRBs in the dataset, we set the most stringent upper limit on muon neutrino emission correlated with gamma-ray bursts. Assuming a Waxman-Bahcall spectrum and incorporating all systematic uncertainties, our flux upper limit has a normalizatio…