TITAN's Digital RFQ Ion Beam Cooler and Buncher, Operation and Performance

We present a description of the Radio Frequency Quadrupole (RFQ) ion trap built as part of the TITAN facility. It consists of a gas-filled, segmented, linear Paul trap and is the first stage of the TITAN setup with the purpose of cooling and bunching radioactive ion beams delivered from ISAC-TRIUMF. This is the first such device to be driven digitally, i.e., using a high voltage ($V_{pp} = \rm{400 \, V}$), wide bandwidth ($0.2 < f < 1.2 \, \rm{MHz}$) square-wave as compared to the typical sinusoidal wave form. Results from the commissioning of the device as well as systematic studies with stable and radioactive ions are presented including efficiency measurements with stable $^{133}$Cs and radioactive $^{124, 126}$Cs. A novel and unique mode of operation of this device is also demonstrated where the cooled ion bunches are extracted in reverse mode, i.e., in the same direction as previously injected.Comment: 34 pages, 17 figure

Role of adenylate cyclase 9 in the pharmacogenomic response to dalcetrapib clinical paradigm and molecular mechanisms in precision cardiovascular medicine

Following the neutral results of the dal-OUTCOMES trial, a genome-wide study identified the rs1967309 variant in the adenylate cyclase type 9 (ADCY9) gene on chromosome 16 as being associated with the risk of future cardiovascular events only in subjects taking dalcetrapib, a CETP (cholesterol ester transfer protein) modulator. Homozygotes for the minor A allele (AA) were protected from recurrent cardiovascular events when treated with dalcetrapib, while homozygotes for the major G allele (GG) had increased risk. Here, we present the current state of knowledge regarding the impact of rs1967309 in ADCY9 on clinical observations and biomarkers in dalcetrapib trials and the effects of mouse ADCY9 gene inactivation on cardiovascular physiology. Finally, we present our current model of the interaction between dalcetrapib and ADCY9 gene variants in the arterial wall macrophage, based on the intracellular role of CETP in the transfer of complex lipids from endoplasmic reticulum membranes to lipid droplets. Briefly, the concept is that dalcetrapib would inhibit CETP-mediated transfer of cholesteryl esters, resulting in a progressive inhibition of cholesteryl ester synthesis and free cholesterol accumulation in the endoplasmic reticulum. Reduced ADCY9 activity, by paradoxically leading to higher cyclic AMP levels and in turn increased cellular cholesterol efflux, could impart cardiovascular protection in rs1967309 AA patients. The ongoing dal-GenE trial recruited 6145 patients with the protective AA genotype and will provide a definitive answer to whether dalcetrapib will be protective in this population.Cardiolog

Supplementary Material for: Palmitic Acid Increases Medial Calcification by Inducing Oxidative Stress

<b><i>Background:</i></b> Aortic medial calcification is a cellular-regulated process leading to arterial stiffness. Although epidemiological studies have suggested an association between the saturation of fatty acids (FA) and arterial stiffness, there is no evidence that saturated FA can induce arterial calcification. This study investigated the capacity of palmitic acid (PA) to induce medial calcification and the signaling pathway(s) implicated in this process. <b><i>Methods:</i></b> Rat aortic segments and vascular smooth muscle cells (VSMC) were exposed to calcification medium supplemented with PA. In vivo, rats were treated with warfarin to induce calcification and fed a PA-enriched diet. <b><i>Results:</i></b> In vitro and ex vivo, palmitate increases calcification and ROS production. Palmitate increases extracellular-signal-regulated kinase (ERK1/2) phosphorylation and osteogenic gene expression. Inhibition of NADPH oxidase with apocynin or an siRNA prevents these effects. ERK1/2 inhibition attenuates the amplification of osteogenic gene expression and calcification induced by palmitate. In vivo, a PA-enriched diet amplified medial calcification and pulse wave velocity (PWV). These effects are mediated by ROS production as indicated by the inhibition of calcification and PWV normalization in rats concomitantly treated with apocynin. <b><i>Conclusion:</i></b> ROS induction by palmitate leads to ERK1/2 phosphorylation and subsequently induces the osteogenic differentiation of VSMC

Direct Mass Measurement of the Four-Neutron Halo Nuclide He-8

A high-precision Penning trap mass measurement of the exotic (8)He nuclide (T(1/2)=119 ms) has been carried out resulting in a reduction of the uncertainty of the halo binding energy by over an order of magnitude. The new mass, determined with a relative uncertainty of 9.2x10(-8) (delta m=690 eV) is 13 keV less bound than the previously accepted value. The mass measurement is of great relevance for the recent charge-radius measurement of (8)He [P. Mueller , Phys. Rev. Lett. 99, 252501 (2007).]. The (8)He mass is the first result from the newly-commissioned Penning trap: TITAN (TRIUMF's Ion Trap for Atomic and Nuclear science) at the ISAC (Isotope Separator and Accelerator) radioactive beam facility at TRIUMF

The Prototype Active-Target Time-Projection Chamber used with TwinSol radioactive-ion beams

International audienceThe study of low-energy reactions with radioactive-ion beams has been greatly enhanced by the recent use of active-target detectors, which have high efficiency and low thresholds to detect low-energy charged-particle decays. Both of these features have been used in experiments with the Prototype Active-Target Time-Projection Chamber to study αα-cluster structure in unstable nuclei and 3-body charged-particle decays after implantation. Predicted αα-cluster structures in 1414C were probed using resonant αα scattering and the nature of the 3-αα breakup of the View the MathML source02+ Hoyle state in 1212C after the beta decay of 1212N and 1212B was studied. These experiments used in-flight radioactive-ion beams that were produced using the dual superconducting solenoid magnets TwinSol at the University of Notre Dame. Preliminary results from these experiments as well as the development of future radioactive beams to be used in conjunction with the PAT-TPC are presented

Direct Mass Measurements to Inform the Behavior of <math display="inline"><mrow><mmultiscripts><mrow><mi>Sb</mi></mrow><mprescripts/><none/><mrow><mn>128</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> in Nucleosynthetic Environments

International audienceNuclear isomer effects are pivotal in understanding nuclear astrophysics, particularly in the rapid neutron-capture process where the population of metastable isomers can alter the radioactive decay paths of nuclei produced during astrophysical events. The β-decaying isomer Sb128m was identified as potentially impactful since the β-decay pathway along the A=128 isobar funnels into this state bypassing the ground state. We report the first direct mass measurements of the Sb128 isomer and ground state using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. We find mass excesses of -84564.8(25)  keV and -84608.8(21)  keV, respectively, resulting in an excitation energy for the isomer of 43.9(33) keV. These results provide the first key nuclear data input for understanding the role of Sb128m in nucleosynthesis, and we show that it will influence the flow of the rapid neutron-capture process