bluuebunny/crossref_metadata_2025_split huggingface dataset:
Landscape heterogeneity influences carbon dioxide production in a young boreal reservoir
Authors: Brothers Soren M. , del Giorgio Paul A. , Teodoru Cristian R. , Prairie Yves T. 
Published: March 2012

Surface carbon dioxide (CO2) emissions exhibit a high degree of spatial heterogeneity in the young boreal Eastmain-1 hydroelectric reservoir, located in northern Quebec, Canada. Estimates of the individual components of net CO2 production within the reservoir (benthic respiration, water column respiration, and primary production) furthermore provide a link between the heterogeneity in surface CO2 emissions and the flooded landscapes below. Specifically, the preflood carbon stock and soil–sediment respiration rates of flooded landscapes were found to influence benthic CO2 production, the rate of decline of hypolimnetic dissolved organic carbon (DOC), and the estimated rate at which flooded landscapes release DOC, further influencing water column respiration rates. Estimates of the individual components of net CO2 production in Eastmain-1 are supported by a positive relationship (t test, r2 = 0.64, P < 0.01) between measured surface CO2 emissions (mean ± SE = 1540 ± 145.4 mg C·m–2·day–1) and independently derived estimates of total net CO2 production (mean ± SE = 1230 ± 162.4 mg C·m–2·day–1). Our findings emphasize the utility of fundamental landscape characterization prior to construction in predicting reservoir greenhouse gas emissions.
Cell surface properties of two differently virulent strains of Acinetobacter baumannii isolated from a patient
Authors: Kempf Marie , Eveillard Matthieu , Deshayes Caroline , Ghamrawi Sarah , Lefrançois Corinne , Georgeault Sonia , Bastiat Guillaume , Seifert Harald , Joly-Guillou Marie-Laure 
Published: March 2012

The aim of this study was to unravel, by focusing on cell surface properties, the underlying virulence factors contributing to the difference in the pathogenicity observed in two Acinetobacter baumannii strains isolated from the same patient. The two strains were phenotypically different: (i) a mucoid strain (AB-M), highly virulent in a mouse model of pneumonia, and (ii) a nonmucoid strain (AB-NM), moderately virulent in the same model. The study of the cell surface properties included the microbial adhesion to solvents method, the measurement of the electrophoretic mobility of bacteria, the analysis of biofilm formation by calcofluor white staining, the adherence to silicone catheters, and scanning electron microscopy. The AB-NM strain was more hydrophobic, more adherent to silicone catheters, and produced more biofilm than the AB-M strain. Scanning electron microscopy showed bacterial cells with a rough surface and the formation of large cell clusters for AB-NM whereas the AB-M strain had a smooth surface and formed only a few cell clusters. Contrary to the results of most previous studies, cell surface properties were not correlated to the virulence described in our experimental model, indicating that mechanisms other than adherence may be involved in the expression of A. baumannii virulence.
Structure of bacterial communities in diverse freshwater habitats
Authors: Aizenberg-Gershtein Yana , Vaizel-Ohayon Dalit , Halpern Malka 
Published: March 2012

The structures and dynamics of bacterial communities from raw source water, groundwater, and drinking water before and after filtration were studied in four seasons of a year, with culture-independent methods. Genomic DNA from water samples was analyzed by the polymerase chain reaction – denaturing gradient gel electrophoresis system and by cloning of the 16S rRNA gene. Water samples exhibited complex denaturing gradient gel electrophoresis genetic profiles composed of many bands, corresponding to a great variety of bacterial taxa. The bacterial communities of different seasons from the four sampling sites clustered into two major groups: (i) water before and after filtration, and (ii) source water and groundwater. Phylogenetic analyses of the clones from the autumn sampling revealed 13 phyla, 19 classes, and 155 operational taxonomic units. Of the clones, 66% showed less than 97% similarities to known bacterial species. Representatives of the phyla Proteobacteria, Bacteroidetes, and Actinobacteria were found at all four sampling sites. Species belonging to the phylum Firmicutes were an important component of the microbial community in filtered water. Representatives of Enterobacteriaceae were not detected, indicating the absence of fecal pollution in the drinking water. Differences were found in the bacterial populations that were sampled from the same sites in different seasons. Each water habitat had a unique bacterial profile. Drinking water harbors diverse and dynamic microbial communities, part of which may be active and resilient to chlorine disinfection. This study provides, for the first time, basic data for uncultivable drinking water bacteria in Israel.
Gas‒phase reactions of NO+ with Glu and γ‒Glu–Met
Authors: Wincel H. , Fokkens R. H. , Nibbering N. M. M. 
Published: March 2012

The reactivity of the nitrosonium ion, NO+, with the amino acid Glu and the dipeptide γ‒Glu–Met in the gas phase has been investigated using the combination of chemical ionisation mass spectrometry and MS/MS. It is shown that NO+ reacts efficiently with both Glu and Glu–Met leading to the formation of the nitroso‒group containing ions at m/z 159 and 288.The formation of m/z 159, (GluNO‒18)+, is rationalized by a mechanism involving an electrophilic attack of NO+ upon the carbonyl oxygen atom of one of the carboxylic groups of Glu and the N‒terminal carboxylic group of Glu–Met leading to the neutral losses of H2O and Met, respectively. The unimolecular decompositions of the metastable and collisionally activated m/z 159 ions lead primarily to the elimination of the neutral species HNO (major) and the (Glu‒18) residue (minor). The formation of the m/z 288 ions can be described by a mechanistic scheme which involves the ion‒molecule interaction of m/z 159 with Glu and Glu–Met and subsequent losses of H2O and Met, respectively. Unimolecular and collisionally activated dissociations of m/z 288 suggest the formation of the proton‒bridged ion‒neutral complex [(GluNO‒18)···H+···(Glu‒18)].
Physical aspects of the interaction of pyrimidine and purine bases with proteins
Authors: Sulkowska A. 
Published: March 2012

The study of complexation of purine and pyrimidine derivatives with two kind of serum albumin using 1H NMR and spectrofluorescence technique are performed in order to obtain model interactions nucleic acid bases–protein.The order of binding strength is as follows: 5mC > 5mU(T) > 3mU > U for pyrimidines and N6mAde > N6Ado > 1mAde > ATP > Ado > Ade for adenine derivatives.The effect of temperature on the hydrophobic interaction between the nitrogen bases and protein has been studied. The destabilization of protein structure causes loss of tertiary structural contacts, indicating that protein conformation is crucial for binding.
Secondary Structure as a Conformational Determinant in Processing of Peptide Precursors at Dibasic Amino Acids
Authors: Lazar Noureddine , Brakch Noureddine , Panchal Maï , Cohen Paul , Rholam Mohamed 
Published: March 2012

The aim of this work was to establish the functional role of selected secondary structure motifs of peptide hormone precursors in their selective recognition by the corresponding converting endoproteases. The strategy was based on the use of synthetic peptides either reproducing or mimicking the sequences of the cleavage regions of two distinct models; i.e. pro‐ocytocin–neurophysin and prosomatostatin. Both prohormones were capable to release their biologically active sequences either by cleavage at a dibasic stretch or by proteolysis at a monobasic site.Both kinetic and thermodynamic parameters of peptide cleavage by various convertases were measured. They were examined in light of structural data on preferred conformations adopted by these substrates, which were obtained by a combination of spectroscopical techniques including CD, FT‐IR and proton NMR. In the case of prosomatostatin, these approaches were in addition paralleled by site‐directed mutagenesis experiments.The wealth of collected data point toward the conclusion that β‐turns and/or loops, favored by sequences bearing basic residues, constitute a key feature in the specification of those peptide loci which are proteolytically processed in vivo. They will be discussed with respect of other processing mechanisms where these mechanisms were also shown.
Continuous assays of glutaminyl cyclase: from development to application
Authors: Schilling Stephan , Demuth Hans-Ulrich 
Published: March 2012

Glutaminyl cyclase (QC, EC 2.3.2.5) catalyses the formation of pyroglutamyl residues from glutamine at the N‐terminus of peptides and proteins. In previously applied assays, QC activity was determined by either analysing the products formed using HPLC coupled with photometric or fluorometric detection, radioimmunoassay, or by detecting the release of ammonia spectrophotometrically. Although these methods are sensitive, they are all discontinuous and therefore time‐consuming and laborious. To conduct a detailed kinetic investigation of QC catalysis, we developed coupled continuous assays suitable for microplates which allow now convenient determination of QC activity. The methods either use pyroglutamyl aminopeptidase or glutamate dehydrogenase as auxiliary enzymes, which results in the liberation of chromophores or fluorophores such as pNA, AMC, βNA or in the conversion of the chromophore NADH/H+ into NAD+, respectively.The assays were applied in various enzyme isolation and characterisation studies, using crude protein solutions as well as purified enzyme in pH‐dependence, substrate and inhibitor specificity investigations. Depending on the respective analytical task, both assays complement each other. Therefore, different enzymatic properties could be explored in more detail. Since the employed strategy of assay development could be of interest also for the analysis of other enzymes, the methods are described here in a comprehensive manner.
13C nuclear magnetic resonance spectroscopy to check 1,3‐random, 2‐random pattern of fatty acid distribution in olive oil triacylglycerols
Authors: Vlahov Giovanna 
Published: March 2012

The fatty acid distribution between the 1,3‐ and 2‐positions of triglycerides was determined in the olive oil set sampled in the Marche region, by using the 13C NMR method which applies the DEPT pulse sequence. The results confirmed that the oleic and linoleic acids were not randomly distributed at the 2‐position of triacylglycerols but were lower for oleic acid and higher for linoleic acid compared to the theoretical values expected for a random distribution. Moreover, the unsaturated acids deviated from the 2‐random distribution at different extents according to the acid concentration of triglyceride.The 13C NMR results, they were obtained for three olive oil samples characterized by high, medium and low oleic acid at 2‐position (Ofound) corresponding to a low, medium, high deviation rate from the 2‐random pattern, were compared to those calculated by the computer program based on the 1,3‐random‐2‐random distribution of fatty acids in the triglycerides.The molar concentrations of the triglyceride species LLL and OLL were calculated from the molar concentrations of oleic and linoleic acids at the 2‐ and 1,3‐positions obtained by using 13C NMR and the computer method. The LLL and OLL triglycerides determined by the computer method were found to be markedly higher in the “high Ofound” oil as compared to NMR. No differences were detected between the two methods for both triglyceride species in the “low Ofound” oil.
Molecular dynamics in calf‐thymus DNA, at neutral and low pH, in the presence of Na+, Ca2+ and Mg2+ ions: A Raman microspectroscopic study
Authors: Muntean Cristina M. , Bratu Ioan 
Published: March 2012

In this paper the Raman total half bandwidths of calf‐thymus DNA vibrations have been measured as a function of pH, monovalent and divalent cations′ type and concentration. The dependence of different band parameters on DNA molecular subgroup structure, on pH and on Na+, Ca2+ and Mg2+ ions concentrations, respectively, are reported. It is shown that changes in (sub)picosecond dynamics of molecular subgroups in calf‐thymus DNA can be monitored with confocal Raman microspectroscopy.The half bandwidths and the global relaxation times for the vibrations at 728 cm−1 (dA), 785 cm−1 (dC), 1094 cm−1 (PO2−), 1377 cm−1 (dA, dG, dT, dC), 1488 cm−1 (dG, dA) and 1580 cm−1 (dG, dA) of calf‐thymus DNA are presented. The full‐widths at half‐height (FWHH) of the bands in calf‐thymus DNA are typically in the wavenumber range from 7.4 to 31 cm−1. The bandwidths in the Raman spectra are sensitive to a dynamics active on a time scale from 0.34 to 1.44 ps.Low pH‐induced melting of double helical structure in calf‐thymus DNA results for some bands in shorter global relaxation times, as a consequence of the increased interaction of the base moieties with the solvent molecules.The molecular dynamics characterizing the 785, 1094, 1377 and 1580 cm−1 vibrations, is faster in the case of high divalent cations DNA sample (pH 7), as compared to the respective low divalent cations DNA sample (pH 7), for both Ca2+ and Mg2+ ions. The vibrational energy transfer process of the guanine band at 1488 cm−1 is slower for the high salt DNA sample, pH 7 as compared to the corresponding low salt DNA sample, pH 7, for both Ca2+ and Mg2+. Molecular dynamics characterizing the vibration at 1488 cm−1 is faster for DNA sample at high Na+ ions (pH 7), as compared to the DNA sample at low Na+ ions (pH 7).As far as the CaDNA and MgDNA complexes are concerned (pH 7), the global relaxation times of some base vibrations decrease for the case of magnesium ions, as compared to the case of the same concentration of calcium ions. The different ionic radius of the two types of metal cations (0.72 Å for Mg and 0.99 Å for Ca) were considered in explaining these results.Molecular relaxation processes of DNA subgroups, upon lowering the pH, in the presence of Na+, Ca2+ and Mg2+ ions are presented. Particularly, at low Ca2+ concentration, upon lowering the pH, the molecular dynamics of DNA subgroups corresponding to vibrations at 728, 1376, 1488 and 1580 cm−1 is much faster, probably due to the denaturation process of the double helical DNA.
Obesity and the Risk for Premenopausal and Postmenopausal Breast Cancer
Authors: Anderson Garnet L. , Neuhouser Marian L. 
Published: March 2012

Abstract
Obesity has been consistently associated with an increased risk of postmenopausal breast cancer in population-based studies. Conversely, obesity in such studies has been inversely associated with premenopausal breast cancer risk. In a report of data from two large chemoprevention trials, both of which enrolled women at a high risk of breast cancer, obesity was associated with only a modest, nonsignificantly increased risk of postmenopausal breast cancer and a surprising statistically significant 70% increased risk of premenopausal breast cancer (vs. normal weight). The discrepancies between these results and those from previous observational studies may be due to differences in study design and exposure ascertainment or due to inherent biologic differences whereby the obesity–breast cancer association differs for high-risk women in the clinical setting compared with general population, average-risk women in the observational setting. Cancer Prev Res; 5(4); 515–21. ©2012 AACR.
Role for Substance P–Based Nociceptive Signaling in Progenitor Cell Activation and Angiogenesis During Ischemia in Mice and in Human Subjects
Authors: Amadesi Silvia , Reni Carlotta , Katare Rajesh , Meloni Marco , Oikawa Atsuhiko , Beltrami Antonio P. , Avolio Elisa , Cesselli Daniela , Fortunato Orazio , Spinetti Gaia , Ascione Raimondo , Cangiano Elisa , Valgimigli Marco , Hunt Stephen P. , Emanueli Costanza , Madeddu Paolo 
Published: March 2012

Background—
Pain triggers a homeostatic alarm reaction to injury. It remains unknown, however, whether nociceptive signaling activated by ischemia is relevant for progenitor cells (PC) release from bone marrow. To this end, we investigated the role of the neuropeptide substance P (SP) and cognate neurokinin 1 (NK1) nociceptor in PC activation and angiogenesis during ischemia in mice and in human subjects.

Methods and Results—
The mouse bone marrow contains sensory fibers and PC that express SP. Moreover, SP-induced migration provides enrichment for PC that express NK1 and promote reparative angiogenesis after transplantation in a mouse model of limb ischemia. Acute myocardial infarction and limb ischemia increase SP levels in peripheral blood, decrease SP levels in bone marrow, and stimulate the mobilization of NK1-expressing PC, with these effects being abrogated by systemic administration of the opioid receptor agonist morphine. Moreover, bone marrow reconstitution with NK1-knockout cells results in depressed PC mobilization, delayed blood flow recovery, and reduced neovascularization after ischemia. We next asked whether SP is instrumental to PC mobilization and homing in patients with ischemia. Human PC express NK1, and SP-induced migration provides enrichment for proangiogenic PC. Patients with acute myocardial infarction show high circulating levels of SP and NK1-positive cells that coexpress PC antigens, such as CD34, KDR, and CXCR4. Moreover, NK1-expressing PC are abundant in infarcted hearts but not in hearts that developed an infarct after transplantation.

Conclusions—
Our data highlight the role of SP in reparative neovascularization. Nociceptive signaling may represent a novel target of regenerative medicine.
The Path to Memory Is Guided by Strategy: Distinct Networks Are Engaged in Associative Encoding under Visual and Verbal Strategy and Influence Memory Performance in Healthy and Impaired Individuals
Authors: Hales Jena B. , Brewer James B. 
Published: March 2012

Abstract
Given the diversity of stimuli encountered in daily life, a variety of strategies must be used for learning new information. Relating and encoding visual and verbal stimuli into memory has been probed using various tasks and stimulus types. Engagement of specific subsequent memory and cortical processing regions depends on the stimulus modality of studied material; however, it remains unclear whether different encoding strategies similarly influence regional activity when stimulus type is held constant. In this study, participants encoded object pairs using a visual or verbal associative strategy during fMRI, and subsequent memory was assessed for pairs encoded under each strategy. Each strategy elicited distinct regional processing and subsequent memory effects: middle/superior frontal, lateral parietal, and lateral occipital for visually associated pairs and inferior frontal, medial frontal, and medial occipital for verbally associated pairs. This regional selectivity mimics the effects of stimulus modality, suggesting that cortical involvement in associative encoding is driven by strategy and not simply by stimulus type. The clinical relevance of these findings, probed in a patient with a recent aphasic stroke, suggest that training with strategies utilizing unaffected cortical regions might improve memory ability in patients with brain damage.
Local Field Potential Activity Associated with Temporal Expectations in the Macaque Lateral Intraparietal Area
Authors: Premereur Elsie , Vanduffel Wim , Janssen Peter 
Published: March 2012

AbstractOscillatory brain activity is attracting increasing interest in cognitive neuroscience. Numerous EEG (magnetoencephalography) and local field potential (LFP) measurements have related cognitive functions to different types of brain oscillations, but the functional significance of these rhythms remains poorly understood. Despite its proven value, LFP activity has not been extensively tested in the macaque lateral intraparietal area (LIP), which has been implicated in a wide variety of cognitive control processes. We recorded action potentials and LFPs in area LIP during delayed eye movement tasks and during a passive fixation task, in which the time schedule was fixed so that temporal expectations about task-relevant cues could be formed. LFP responses in the gamma band discriminated reliably between saccade targets and distractors inside the receptive field (RF). Alpha and beta responses were much less strongly affected by the presence of a saccade target, however, but rose sharply in the waiting period before the go signal. Surprisingly, conditions without visual stimulation of the LIP-RF-evoked robust LFP responses in every frequency band—most prominently in those below 50 Hz—precisely time-locked to the expected time of stimulus onset in the RF. These results indicate that in area LIP, oscillations in the LFP, which reflect synaptic input and local network activity, are tightly coupled to the temporal expectation of task-relevant cues.
Granting Citizenship-related Rights to Third-Country Nationals: An Alternative to the Full Extension of European Union Citizenship?
Authors: Wiesbrock Anja 
Published: March 2012

Abstract
This article discusses the extension of citizenship-related rights to third-country nationals (TCNs) and their analogous interpretation with the rights enjoyed by European Union citizens. Starting with a discussion of the limited possibilities of fully extending Union citizenship to TCNs, it proceeds to discuss the Court’s case law regarding the application of EU general principles of law to TCNs and the interpretation of Union law concepts. It is argued that granting TCNs citizenship-related rights, such as the right to move freely within the EU and the right to non-discrimination on grounds of nationality, and their analogous interpretation with the rights enjoyed by Union citizens constitute a viable alternative to the full extension of Union citizenship.
Electoral Conflict and Justice: The Case of Zimbabwe
Authors: Nyamutata Conrad 
Published: March 2012

Abstract
In recent years, Africa has faced a new form of conflict arising from disputed elections. Incumbents have refused to vacate office after apparently losing elections, triggering violent conflict. Regional organisations have invested considerable political energy to manage these conflicts. Post-electoral conflict accords (PECAs) resulting in power-sharing have been the favoured modus vivendi with regional mediators. However, little attention has been paid to the crucial issue of justice in the management of these disputes. Like most conflicts, electoral conflict centres on perceived injustice in the electoral process. Therefore, in order to manage these conflicts in an effective way, justice must be acknowledged in both procedural and substantive content. This article focuses on management of electoral conflict in Zimbabwe. It argues that the protracted post-electoral conflict in Zimbabwe can be explained, to a large extent, through failure to acknowledge procedural, distributive and retributive justice concerns.