The Integrative Approach to Study of the Structure and Functions of Cardiac Voltage-Dependent Ion Channels

Crystallography Reports - Membrane proteins, including ion channels, became the focus of structural proteomics midway through the 20th century. Methods for studying ion channels are diverse and...     

Gas phase chromatography of halides of elements 104 and 105

On-line isothermal gas phase chromatography was used to study halides of²⁶¹104 (T_1/2=65 s) and^262,263105 (T_1/2=34 s and 27 s) produced an atom-at-a time via the reactions²⁴⁸Cm(¹⁸O, 5n) and²⁴⁹Bk(¹⁸O, 5n, 4n), respectively. Using HBr and HCl gas as halogenating agents, we were able to produce volatile bromides and chlorides of the above mentioned elements and study their behavior compared to their lighter homologs in Groups 4 or 5 of the periodic table. Element 104 formed more volatile bromide than its homolog Hf. In contrast, element 105 bromides were found to be less volatile than the bromides of the group 5 elements Nb and Ta. Both 104 and Hf chlorides were observed to be more volatile than their respective bromides.     

In situ TEM characterisation of dislocation interactions in α-titanium

In situ straining in the transmission electron microscope and diffraction-contrast electron tomography has been applied to investigate dislocation interactions in α-Ti. Dislocation debris, in the form of small loops, was seen to form from sequential cross-slip events. Electron tomography provided direct three-dimensional visualisation of the dislocation structures, allowing accurate identification of slip planes, dislocation line directions and spatial relations between dislocations.     

On the strong field dependence and nonlinear response to gadolinium contrast agent of proton transverse relaxation rates in dairy cream

Dairy cream, as a suspension of lipid droplets in water, is a potentially useful magnetic resonance imaging (MRI) phantom material and an interesting material for studying fundamental relaxation mechanisms. Here we report a strong increase in the transverse relaxation rates with field strength for both the water and lipid protons in dairy cream. Also, studies at 4.7 T reveal a nonlinear response of transverse relaxation rates with increasing concentration of a common gadolinium (Gd)-based contrast agent, including an initial decrease of water relaxation rates as measured with Hahn spin echoes at the lower Gd concentrations. The results are treated within the framework of a model in which the magnetic susceptibility difference between the lipid droplets and the aqueous phase plays the prominent role for transverse relaxation. Second-order polynomial fits of the water proton transverse relaxation rate dependence on field strength and on Gd concentration at 4.7 T provided experimental parameters from which model parameters are extracted and compared with expectations available from the literature.     

First chemical on-line separation and detection of a subsecond α-decaying nuclide, 224Pa

Subsecond ²²⁴ Pa (T _1/2 = 0.85 s) was produced via the ²⁰⁹ Bi(¹⁸ O,3n)²²⁴ Pa reaction at the 88 inch cyclotron at the Lawrence Berkeley National Laboratory. After production it was transported via a gas-jet system to the centrifuge system SISAK 3. Following on-line extraction with trioctylamine/scintillation solutions from 1M lactic acid, ²²⁴ Pa was detected applying on-line -liquid scintillation counting. Unambiguous identification was achieved using time-correlated --decay chain analysis. This constitutes the first chemical on-line separation and detection of a subsecond -decaying nuclide, 0.85-s ²²⁴ Pa with the fast extraction system SISAK 3.