17 research outputs found
Tomonaga-Luttinger features in the resonant Raman spectra of quantum wires
The differential cross section for resonant Raman scattering from the
collective modes in a one dimensional system of interacting electrons is
calculated non-perturbatively using the bosonization method. The results
indicate that resonant Raman spectroscopy is a powerful tool for studying
Tomonaga-Luttinger liquid behaviour in quasi-one dimensional electron systems.Comment: 4 pages, no figur
Measurement of the Neutron Spin Structure Function with a Polarized ^3He Target
Results are reported from the HERMES experiment at HERA on a measurement of
the neutron spin structure function in deep inelastic scattering
using 27.5 GeV longitudinally polarized positrons incident on a polarized
He internal gas target. The data cover the kinematic range
and . The integral evaluated at a fixed of is . Assuming Regge behavior at low , the first
moment is .Comment: 4 pages TEX, text available at
http://www.krl.caltech.edu/preprints/OAP.htm
Passive Q-switching and mode-locking for the generation of nanosecond to femtosecond pulses
Electron cyclotron resonance heating on TEXTOR: Results from the preliminary 110 GHz system
Trimetrexate as biochemical modulator of 5-fluorouracil/leucovorin in advanced colorectal cancer: final results of a randomised European study
Electron cyclotron resonance heating on TEXTOR
TEXTOR is equipped with two gyrotrons at 110 and 140 GHz, respectively. Both share a single power supply and a confocal quasi-optical transmission line. They cannot be operated simultaneously. The 110-GHz gyrotron with limited power and pulse length (300 kW; 200 ms) has been used in a first series of experiments on electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) and for collective Thomson scattering (CTS) diagnostics of energetic ions. In the future the 110-GHz gyrotron will be operated exclusively for CTS diagnostics, while for ECRH and ECCD, the newly installed 140-GHz, high-power (800-kW), long-pulse (>3-s) gyrotron is now available. The highlights of first ECRH experiments with the 110-GHz gyrotron are reported. These include observations of internal transport barriers with ECRH on various target plasmas: in the current plateau phase of both ohmic and radiation improved mode (RI-mode) discharges. In addition, sawtooth control by localized ECRH is demonstrated. First results on CTS include the observation of the slowing down of energetic ions and of the redistribution of energetic ions in sawtooth crashes
Electron cyclotron resonance heating on TEXTOR
The 110 GHz and the new 140 GHz gyrotron systems for electron cyclotron resonance heating (ECRH) and ECCD on TEXTOR are described and results of ECRH experiments with the 110 GHz system are reported. Central ECRH on Ohmic plasmas shows the presence of an internal electron transport barrier near q = 1. This is confirmed by modulated ECRH experiments. A central barrier is also indicated by ECRH in radiatively improved (RI) mode discharges and up to two barriers are seen with ECRH during the current ramp phase. ECRH control of sawteeth is reported for both Ohmic and RI mode target plasmas
Mutations in PPCS, encoding phosphopantothenoylcysteine synthetase, cause autosomal-recessive dilated cardiomyopathy.
Coenzyme A (CoA) is an essential metabolic cofactor used by around 4% of cellular enzymes. Its role is to carry and transfer acetyl and acyl groups to other molecules. Cells can synthesize CoA de novo from vitamin B5 (pantothenate) through five consecutive enzymatic steps. Phosphopantothenoylcysteine synthetase (PPCS) catalyzes the second step of the pathway during which phosphopantothenate reacts with ATP and cysteine to form phosphopantothenoylcysteine. Inborn errors of CoA biosynthesis have been implicated in neurodegeneration with brain iron accumulation (NBIA), a group of rare neurological disorders characterized by accumulation of iron in the basal ganglia and progressive neurodegeneration. Exome sequencing in five individuals from two unrelated families presenting with dilated cardiomyopathy revealed biallelic mutations in PPCS, linking CoA synthesis with a cardiac phenotype. Studies in yeast and fruit flies confirmed the pathogenicity of identified mutations. Biochemical analysis revealed a decrease in CoA levels in fibroblasts of all affected individuals. CoA biosynthesis can occur with pantethine as a source independent from PPCS, suggesting pantethine as targeted treatment for the affected individuals still alive