Critical current degradation in HTS wires due to cyclic mechanical strain

HTS wires, which may be used in many devices such as magnets and rotating machines, may be subjected to mechanical strains from electromagnetic, thermal and centripetal forces. In some applications these strains will be repeated several thousand times during the lifetime of the device. We have measured critical current degradation due to repeated strain cycles for both compressive and tensile strains. Results for BSCCO-2223 HTS conductor samples are presented for strain values up to 0.5% and cycle numbers up to and beyond 10/sup 4/

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Oleic Acid Biosynthesis in Plasmodium falciparum: Characterization of the Stearoyl-CoA Desaturase and Investigation as a Potential Therapeutic Target

BACKGROUND:Plasmodium falciparum parasitization of erythrocytes causes a substantial increase in the levels of intracellular fatty acids, notably oleic acid. How parasites acquire this monounsaturated fatty acid has remained enigmatic. Here, we report on the biochemical and enzymatic characterization of stearoyl-CoA desaturase (SCD) in P. falciparum. METHODOLOGY/PRINCIPAL FINDINGS:Metabolic labeling experiments allowed us to demonstrate the production of oleic acid from stearic acid both in lysates of parasites incubated with [(14)C]-stearoyl-CoA and in parasite-infected erythrocytes labeled with [(14)C]-stearic acid. Optimal SCD activity was detected in schizonts, the stage of maximal membrane synthesis. This activity correlated with a late trophozoite stage-specific induction of PFE0555w transcripts. PFE0555w harbors a typical SCD signature. Similar to mammalian SCDs, this protein was found to be associated with the endoplasmic reticulum, as determined with PFE0555w-GFP tagged transgenic P. falciparum. Importantly, these parasites exhibited increased rates of stearic to oleic acid conversion, providing additional evidence that PFE0555w encodes the plasmodial SCD (PfSCD). These findings prompted us to assess the activity of sterculic acid analogues, known to be specific Delta9-desaturase inhibitors. Methyl sterculate inhibited the synthesis of oleic acid both with parasite lysates and infected erythrocytes, most likely by targeting PfSCD. This compound exhibited significant, rapid and irreversible antimalarial activity against asexual blood stages. This parasiticidal effect was antagonized by oleic acid. CONCLUSION/SIGNIFICANCE:Our study provides evidence that parasite-mediated fatty acid modification is important for blood-stage survival and provides a new strategy to develop a novel antimalarial therapeutic based on the inhibition of PfSCD

Developmental Compartments In The Drosophila-Melanogaster Wing Disk

Distribution of the enzyme aldehyde oxidase (AO) within the pouch of the mature wing disc is precise and differential. General locations of compartmental boundaries have been identified by fate mapping and studies of AO distribution. The suspected locations of the boundaries were verified by analyzing the distribution of AO-negative cells within an AO-stained background in gynandromorphs and in X-ray-induced clones of AO-negative cells. The anterior/posterior border appeared slightly anterior to the junction of the AO+ anterior presumptive wing surfaces and AO− posterior wing surfaces. A narrow band of AO+ cells extending proximodistally on both presumptive wing surfaces belongs to the posterior compartment. Two dorsal/ventral (dor./vent.) restrictions were found. The dor./vent. restriction equivalent to the dor./vent. border found in the adult wing was located at the ventral most edge of the AO-stained presumptive wing margin. A second restriction which was less strictly obeyed was found on the dorsal edge of the wing margin. We conclude that the whole presumptive wing margin is part of the dorsal compartment. Within the anterior wing margin an intensively stained oval was also found to be clonally restrictive. Therefore, territories were found within the prospective wing margin for which no such features have been identified in the adult Drosophila melanogaster wing