The synthesis of monofluoroacetic acid by a tissue culture ofAcacia georginae

Zusammenfassung Gewebekulturen vonAcacia georginae vermögen Fluorid-Ionen aus dem Kulturmedium in Fluoressigsäure umzuwandeln.     

Association of asymmetric unit membrane plaque formation in the urinary bladder of adult humans with therapeutic radiation

Summary Asymmetric unit membrane (AUM) is a component of the luminal membrane of urinary bladder in many species. In normal human adults it is inconspicuous, but it becomes prominent following incidental exposure to therapeutic irradiation.This work was supported by the Otho S.A. Sprague Memorial Institute.     

Differential olfactory perception of enantiomeric compounds by blind subterranean mole rats (Spalax ehrenbergi)

The behavior of mole rats (Spalax ehrenbergi) near pairs of enantiomeric compounds was examined in 901 two-choice experimental tests. Positioning of the nest and food store and the preferred location of the tested animal were used to assess attraction or aversion to the tested odorants. The results indicated that mole rats respond differentially to odors of stereoisomers (enantiomers of carvone, citronellol, and fechone). They responded to one enantiomer of each tested pair but were indifferent to or did not smell the other. Both sexes were attracted to the odor of R-(–)-carvone and repelled by the odor of (+)-citronellol. Females were attracted to the odor of (–)-fenchone while males had no preference. By contrast, all animals were indifferent to or did not smell the odor of S-(+)-carvone, (–)-citronellol, and (+)-fenchone. Further research to distinguish between these alternatives (indifference vs hyposmia/anosmia) is suggested.     

Association of asymmetric unit membrane plaque formation in the urinary bladder of adult humans with therapeutic radiation

Asymmetric unit membrane (AUM) is a component of the luminal membrane of urinary bladder in many species. In normal human adults it is inconspicuous, but it becomes prominent following incidental exposure to therapeutic irradiation.     

Substrate-modulated gating dynamics in a Na+-coupled neurotransmitter transporter homologue

Neurotransmitter/Na(+) symporters (NSSs) terminate neuronal signalling by recapturing neurotransmitter released into the synapse in a co-transport (symport) mechanism driven by the Na(+) electrochemical gradient. NSSs for dopamine, noradrenaline and serotonin are targeted by the psychostimulants cocaine and amphetamine, as well as by antidepressants. The crystal structure of LeuT, a prokaryotic NSS homologue, revealed an occluded conformation in which a leucine (Leu) and two Na(+) are bound deep within the protein. This structure has been the basis for extensive structural and computational exploration of the functional mechanisms of proteins with a LeuT-like fold. Subsequently, an 'outward-open' conformation was determined in the presence of the inhibitor tryptophan, and the Na(+)-dependent formation of a dynamic outward-facing intermediate was identified using electron paramagnetic resonance spectroscopy. In addition, single-molecule fluorescence resonance energy transfer imaging has been used to reveal reversible transitions to an inward-open LeuT conformation, which involve the movement of transmembrane helix TM1a away from the transmembrane helical bundle. We investigated how substrate binding is coupled to structural transitions in LeuT during Na(+)-coupled transport. Here we report a process whereby substrate binding from the extracellular side of LeuT facilitates intracellular gate opening and substrate release at the intracellular face of the protein. In the presence of alanine, a substrate that is transported ～10-fold faster than leucine, we observed alanine-induced dynamics in the intracellular gate region of LeuT that directly correlate with transport efficiency. Collectively, our data reveal functionally relevant and previously hidden aspects of the NSS transport mechanism that emphasize the functional importance of a second substrate (S2) binding site within the extracellular vestibule. Substrate binding in this S2 site appears to act cooperatively with the primary substrate (S1) binding site to control intracellular gating more than 30?? away, in a manner that allows the Na(+) gradient to power the transport mechanism.     

Improved Pinning Center Morphology in HTS with Order-of-Magnitude Increase in J_c and B_pin Compared to Columnar Pinning

The motivation for continuous columnar pinning centers has been to provide maximum Upin. It has been assumed that this provides the best Jc and Bpin. Limitations on Jc and Spin observed for columnar pinning have been attributed to degradation of the order parameter and Tc. We examine columnar pinning by ionic damage and conclude instead that geometrical effects of columnar pinning on percolation path and on the number of pinning centers are the dominant limitations of columnar pinning, leading to a limit of Bpin- 4 T. Evidence suggests that multiple-in-line-defects (MILD) are far better suited to increase Jc and Bpin. The morphology of MILD pinning is reviewed. Ion energy loss per unit distance, Se, is found to be most promising in a regime almost diametrically opposite to that sought to maximize Upin. We expect Jc - 106 A/cm2 and Bpin > 40T from MILD pinning, despite sharply decreased Upin. Experimental confirmation is proposed.     

Improved Pinning Center Morphology in HTS with Order－of－Magnitude Increase in Jc and Bpin Compared to Columnar Pinning

The motivation for continuous columnar pinning centers has been to provide maximum Upin It has been assumed that this provides the best Jc and Bpin. Limitations on Jc and Bpin, observed for columnar pinning have been attributed to degradation of the order parameter and Tc. We examine columnar pinning by ionic damage and cooclude instead that geometrical effects of columnar pinning on percolation path and on the number of pinning centers are the dominant limitations of columnar pinning, leading to a limit of Bpin—4T.Evidence suggests that multiple-in-line-defects (MILD) are far better suited to increase Jc and Bpin,. The morphology of MILD pinning is reviewed. Ion energy loss per unit distance, Se, is found to be most promising in a regime almost diametrically opposite to that sought to maximize Upin. We expect Jc—10^6 A/cm^2 and Bpin＞,40 T from MILD pinning, despite sharply decreased Upin. Experimental confirmation is proposed.