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.     

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.     

Structure of gap junctions in cultures of normal and neoplastic bladder epithelial cells

Summary Normal rat urinary bladder epithelial cells contain small subunit (PF-1) and large subunit (PF-2) gap junctions, whereas carcinoma cells only contain PF-1 gap junctions. The absence of PF-2 gap junctions, which are composed of larger connexons with slightly larger ionic channels, may contribute to altered metabolic coupling between urinary bladder carcinoma cells.Acknowledgments. The authors wish to thank Ms Denise Wiler and Mr William Leonard for expert technical assistance. This work was supported by funds from the National Cancer Institute, CA-25034, and in part by the Otho SA Sprague Memorial Institute.     

Voltage-dependent translocation of the asialoglycoprotein receptor across lipid membranes

A membrane receptor protein for asialoglycoproteins induces voltage-dependent increases in ion conductance across a lipid bilayer, probably reflecting penetration of the protein into the bilayer towards an electrically positive pole. In the presence of specific ligand for the receptor, this penetration leads to a 'translocation' of the receptor from one side of the bilayer to the other. These observations suggest a mechanism by which biological membranes might regulate the disposition of their proteins, and a way in which membrane receptors involved in endocytosis might be spared lysosomal destruction in order to be recycled to the plasma membrane.     

Synthetic RNA-dependent DNA polymerase activity in normal rat liver and hepatomas

Normal adult rat liver contains a high level of a synthetic RNA-dependent DNA polymerase activity, which is distinct from cellular DNA-dependent polymerases. It uses poly(dT).poly(rA) and poly(rA).poly(rU) as templates but has little or no response to DNA or several single-stranded RNAs.     

The crystal structure of murrayazoline (Mahanimbidine,curryangin)

Riassunto La struttura del murrayazoline, un'alcoloide carbazole, é stata confermata per via cristallografica con i raggi X.     

Sesquiterpenoids minor constituents ofPinus parviflora. On the relationship between (−)-δ-cadinol, (+)-δ-cadinol,sesquigoyol, torreyol,and brown alga cadinol

Zusammenfassung 1-Dokosanol, Sesquigoyol,-Sitosterin und 3,5-Dimethoxystilben wurden ausP. formosana isoliert. Es konnte gezeigt werden, dass Sesquigoyol der optische Antipode von (–)--Cadinol ist.

---

---

Sesquiterpenoids II. For the previous paper in this series, seeW. G. Dauben, B. Weinstein, P. Lim, andA. B. Anderson, Tetrahedron15, 217 (1961).

---

On leave of absence from the Department of Chemistry, National Taiwan University, Taipei, Taiwan, Republic of China.

---

The National Council of Science, Republic of China, is thanked for the award of a fellowship for advanced study to one of us (K.-T.W.).