Cloning of a cDNA coding for an amino acid carrier from Ricinus communis (RcAAP1) by functional complementation in yeast: kinetic analysis, inhibitor sensitivity and substrate specificity

AbstractA cDNA for the amino acid permease gene RcAAP1 has been isolated from Ricinus communis by yeast complementation and subjected to a detailed kinetic analysis. RcAAP1 cDNA is 1.5 kb with an open reading frame that codes for a protein with 486 amino acids and a calculated molecular mass of 53.1 kDa. RcAAP1-mediated histidine uptake was pH dependent with highest transport rates at acidic pH; it was sensitive to protonophores and uncouplers and the Km for histidine uptake was 96 μM. The substrate specificity was investigated by measuring the levels of inhibition of histidine uptake by a range of amino acids. The basic amino acids (histidine, lysine and arginine) showed strongest inhibition of uptake whereas acidic amino acids competed less effectively. Alanine was the most efficient competitor of the neutral amino acids. Glutamine, serine, asparagine, methionine and cysteine showed moderate inhibition whereas threonine, isoleucine, leucine, phenylalanine, tyrosine and tryptophan showed only low levels of inhibition. Glycine, proline and citrulline caused slight stimulation. More detailed competition kinetics indicated that both lysine and arginine showed simple competitive inhibition of histidine uptake. When direct uptake measurements were carried out, both lysine and arginine were found to be effective substrates for RcAAP1

What do coronary artery disease patients think about their treatments? An assessment of patients' treatment representations

This article investigates patients' beliefs about the intervention offered to manage their illness. Coronary artery disease (CAD) patients, 70 of whom were undergoing medication, 71 to undergo angioplasty and 73 to undergo surgery, completed a 58-item questionnaire regarding their treatment beliefs. Responses were subject to principal components analysis, which indicated four factors accounting for 36.7 per cent of the variance. After excluding extraneous items, the final questionnaire consisted of 27 items, clustered around four components: treatment-value, treatment-concerns, decision-satisfaction and cure. A coherent set of subscale inter-correlations and ANCOVAs examining treatment group differences on these sub-scales showed a logical, explicable pattern of group differences reflecting the distinctive natures of each treatment and demonstrated discriminant validity. Correlations with other scales provided evidence of construct validity

On the variability of simulated source-receptor relationships for sulfur deposition

The use of Lagrangian models to estimate source-receptor relationships for ambient SO 4 = concentrations and S deposition has become fairly widespread over the past several years. This paper addresses the sensitivity of long-term simulations of a Lagrangian S transport and deposition model to actual variations in SO 2 emissions and meteorological conditions. The variations of predicted source-receptor relationships due to (1) the inclusion of day to day variations in emissions strength as opposed to the use of the annual average daily emission rate and (2) year-to-year variations in meteorological conditions were studied to identify causes of uncertainty in a Lagrangian model. The results suggested that adding information on day to day emission variations for a specific point source resulted in variations in estimated S wet deposition of the order of only 20% within 500 km of the source.Year-to-year variations in meteorological conditions, on the other hand, resulted in variations in predicted S wet deposition of the order of 50% for some receptors. The variation in estimated source-receptor relationships for a given source/receptor combination was found to range as high as 70% over a 5-yr modeling period.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43900/1/11270_2004_Article_BF00303346.pd

Measuring the Spectra of High Energy Neutrinos with a Kilometer-Scale Neutrino Telescope

We investigate the potential of a future kilometer-scale neutrino telescope such as the proposed IceCube detector in the South Pole, to measure and disentangle the yet unknown components of the cosmic neutrino flux, the prompt atmospheric neutrinos coming from the decay of charmed particles and the extra-galactic neutrinos, in the 10 TeV to 1 EeV energy range. Assuming a power law type spectra, $d\phi_\nu/dE_\nu \sim \alpha E_\nu^\beta$, we quantify the discriminating power of the IceCube detector and discuss how well we can determine magnitude ($\alpha$) as well as slope ($\beta$) of these two components of the high energy neutrino spectrum, taking into account the background coming from the conventional atmospheric neutrinos.Comment: 21 pages, 7 figure

Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2

We have searched for the proton decay mode proton to neutrino K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0. We found one candidate event consistent with background, yielding a limit, tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters

Low energy atmospheric muon neutrinos in MACRO

We present the measurement of two event samples induced by atmospheric $\nu_\mu$ of average energy $\bar {E}_\nu \sim 4 GeV$. In the first sample, the neutrino interacts inside the MACRO detector producing an upward-going muon leaving the apparatus. The ratio of the number of observed to expected events is $0.57 \pm0.05_{stat} \pm0.06_{syst} \pm0.14_{theor}$ with an angular distribution similar to that expected from the Bartol atmospheric neutrino flux. The second is a mixed sample of internally produced downward-going muons and externally produced upward-going muons stopping inside the detector. These two subsamples are selected by topological criteria; the lack of timing information makes it impossible to distinguish stopping from downgoing muons. The ratio of the number of observed to expected events is $0.71 \pm 0.05_{stat} \pm0.07_{syst} \pm0.18_{theor}$ . Using the ratio of the two subsamples (for which most theoretical uncertainties cancel) we can test the pathlength dependence of the oscillation hypothesis. The probability of agreement with the no-oscillation hypothesis is 5% . The deviations of our observations from the expectations has a preferred interpretation in terms of $\nu_\mu$ oscillations with maximal mixing and $\Delta m^2 \sim 10^{-3} \div 10^{-2} eV^2$. These parameters are in agreement with our results from upward throughgoing muons, induced by $\nu_\mu$ of much higher energies.Comment: 7 pages, 6 figures. Submitted to Phys. Lett.

Foreign policy beliefs and support for Stephen Harper and the Conservative Party

Similar to other recent Canadian elections, foreign policy did not feature prominently in the 2011 federal election campaign. In fact, many doubt Canadian public opinion on international affairs is linked to the actions taken by recent Governments. In this paper, we examine Canadian public opinion toward a range of foreign policy issues and argue that the survey questions measure two latent dimensions —militarism and internationalism. Our survey evidence indicates the existence of an “issue public” which is prepared to endorse military action and is skeptical of human rights and overseas aid programs, and this group is far more supportive of Prime Minister Harper and the Conservative Party than other Canadians. The absence of an elite discussion, either among politicians or between media elites, about the direction of Canadian foreign policy does not prevent the Canadian voter from thinking coherently about questions pertaining to this issue domain and employing these beliefs to support or oppose political parties and their leaders

Adsorption of mono- and multivalent cat- and anions on DNA molecules

Adsorption of monovalent and multivalent cat- and anions on a deoxyribose nucleic acid (DNA) molecule from a salt solution is investigated by computer simulation. The ions are modelled as charged hard spheres, the DNA molecule as a point charge pattern following the double-helical phosphate strands. The geometrical shape of the DNA molecules is modelled on different levels ranging from a simple cylindrical shape to structured models which include the major and minor grooves between the phosphate strands. The densities of the ions adsorbed on the phosphate strands, in the major and in the minor grooves are calculated. First, we find that the adsorption pattern on the DNA surface depends strongly on its geometrical shape: counterions adsorb preferentially along the phosphate strands for a cylindrical model shape, but in the minor groove for a geometrically structured model. Second, we find that an addition of monovalent salt ions results in an increase of the charge density in the minor groove while the total charge density of ions adsorbed in the major groove stays unchanged. The adsorbed ion densities are highly structured along the minor groove while they are almost smeared along the major groove. Furthermore, for a fixed amount of added salt, the major groove cationic charge is independent on the counterion valency. For increasing salt concentration the major groove is neutralized while the total charge adsorbed in the minor groove is constant. DNA overcharging is detected for multivalent salt. Simulations for a larger ion radii, which mimic the effect of the ion hydration, indicate an increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

All-particle cosmic ray energy spectrum measured with 26 IceTop stations

We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 km^2. The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenith angle ranges between 0{\deg} and 46{\deg}. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles {\theta} < 30{\deg}, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed between 3.5 and 4.32 PeV, depending on composition assumption. Spectral indices above the knee range from -3.08 to -3.11 depending on primary mass composition assumption. Moreover, an indication of a flattening of the spectrum above 22 PeV were observed.Comment: 38 pages, 17 figure