This paper presents a theoretical analysis of a possible scheme to realize a strong population difference between the two ground state sub-levels F = 4, MF = 0, and F = 3, MF = 0 of caesium atom. Two laser-diode light beams, π polarized, are used to illuminate at right angle an atomic beam. The efficiency of the population difference build up is evaluated for two limiting cases according to the light spectral distribution : the monochromatic and broadband excitations. This analysis takes into account hyperfine and Zeeman structures of the energy levels. Numerical calculations show that the monochromatic excitation leads to steady state population difference close to the value obtained with a single pumping laser; however all the atoms can be brought in the upper level if the two laser lights are considered broadband and uncorrelated Guidelines are derived to obtain an efficient optically pumped caesium beam frequency standard.
No abstract is provided for this article.
Brivudin, ((<i>E</i>)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) can be considered the gold standard for the treatment of varicella-zoster virus (VZV) infections, such as herpes zoster (shingles). It is available for clinical use in most European countries (except for the UK) and over the whole world (except for the US and Canada). Besides VZV its activity spectrum also includes various other herpesviruses, such as herpes simplex virus type 1 (HSV-1). Its activity against VZV and HSV-1 depends on phosphorylation by the virus-encoded thymidine kinase (TK). In its active form (BVDU TP or BVDU 5'-triphosphate), it can act as both substrate and inhibitor of the viral (i.e., HSV-1) DNA polymerase. It has proven to be effective against herpes zoster, including post-herpetic neuralgia (PHN). It is contra-indicated in patients concomitantly treated by 5-fluorouracil (FU), since its degradation product, (<i>E</i>)-5-(2-bromovinyl)uracil, is inhibitory to the catabolism of FU, which may enhance the toxicity of the latter. A new compound, the bicyclic nucleoside analogue (BCNA) Cf-1743, has been described, which is a more potent inhibitor of VZV replication than BVDU and which does not interfere with the catabolism of FU. It is applicable orally, as its 5'-valine ester FV-100 (Fermavir), but has not (yet) been marketed for clinical use.
NF-kappaB (NF-kappaB), the transcription factors of HIV-1, play an important role in triggering HIV transcription. The inhibition of NF-kappaB activation and their signaling pathway offers a potential anti-HIV therapy strategy. This review reports the mode of action of NF-kappaB in triggering HIV-1 transcription and the status of the inhibitors.
