Influence of Charge Order on the Ground States of TMTTF Molecular Salts

(TMTTF)2AsF6 and (TMTTF)2SbF6 are both known to undergo a charge ordering phase transition, though their ground states are different. The ground state of the first is Spin-Peierls, and the second is an antiferromagnet. We study the effect of pressure on the ground states and the charge-ordering using 13C NMR spectroscopy. The experiments demonstrate that the the CO and SP order parameters are repulsive, and consequently the AF state is stabilized when the CO order parameter is large, as it is for (TMTTF)2SbF6. An extension of the well-known temperature/pressure phase diagram is proposed.Comment: 5pages, 5 figures, Proceeding of ISCOM2003, to appear in Journal de Physique I

Diffraction of partial temporal coherence beam from multi slits

We have generalized the notion of Franhoufer diffraction of temporal coherent light from a single slit to the case of arbitrary n slits. A general numerical method has been developed for the simulation of the diffraction pattern of multi-slits which is also used to study the effects of coherence length on the diffraction pattern. The diffraction pattern is investigated for different values of recently introduced parameter, decoherence parameter. It is shown that for multi-slits, the temporal decoherence effects appear for decoherence parameter more or equal to one. The results of our study reproduce the previous studies for perfect temporal case, when coherence length tends to infinity.Comment: 13 pages,7 figure

Regional differences in the coupling between resting cerebral blood flow and metabolism may indicate action preparedness as a default state.

Although most functional neuroimaging studies examine task effects, interest intensifies in the "default" resting brain. Resting conditions show consistent regional activity, yet oxygen extraction fraction constancy across regions. We compared resting cerebral metabolic rates of glucose (CMRgl) measured with 18F-labeled 2-fluoro-2-deoxy-D-glucose to cerebral blood flow (CBF) 15O-H2O measures, using the same positron emission tomography scanner in 2 samples (n = 60 and 30) of healthy right-handed adults. Region to whole-brain ratios were calculated for 35 standard regions of interest, and compared between CBF and CMRgl to determine perfusion relative to metabolism. Primary visual and auditory areas showed coupling between CBF and CMRgl, limbic and subcortical regions--basal ganglia, thalamus and posterior fossa structures--were hyperperfused, whereas association cortices were hypoperfused. Hyperperfusion was higher in left than right hemisphere for most cortical and subcallosal limbic regions, but symmetric in cingulate, basal ganglia and somatomotor regions. Hyperperfused regions are perhaps those where activation is anticipated at short notice, whereas downstream cortical modulatory regions have longer "lead times" for deployment. The novel observation of systematic uncoupling of CBF and CMRgl may help elucidate the potential biological significance of the "default" resting state. Whether greater left hemispheric hyperperfusion reflects lateral dominance needs further examination

Improved sensitivity RF photonics doppler frequency measurement system

An improved sensitivity Doppler frequency measurement system based on microwave photonics technology was demonstrated practically. The system employs a four-wave mixing effect to achieve broad radio-frequency (RF) frequency measurement. In addition, a lock-in amplification technique was utilized to achieve high-measurement sensitivity. The system is, thus, capable of Doppler frequency estimation of radar echoes with a carrier frequency up to 40 GHz and a power level as low as $-$35 dBm. © 2009-2012 IEEE

Anthelmintics for drug repurposing : opportunities and challenges

Drug repositioning is defined as a process to identify a new application for drugs. This approach is critical as it takes advantage of well-known pharmacokinetics, pharmacodynamics, and toxicity profiles of the drugs; thus, the chance of their future failure decreases, and the cost of their development and the required time for their approval are reduced. Anthelmintics, which are antiparasitic drugs, have recently demonstrated promising anticancer effects in vitro and in vivo. This literature review focuses on the potential of anthelmintics for repositioning in the treatment of cancers. It also discusses their pharmacokinetics and pharmacodynamics as antiparasitic drugs, proposed anticancer mechanisms, present development conditions, challenges in cancer therapy, and strategies to overcome these challenges