Electromagnetically induced transparency in cold 85Rb atoms trapped in the ground hyperfine F = 2 state

We report electromagnetically induced transparency (EIT) in cold 85Rb atoms, trapped in the lower hyperfine level F = 2, of the ground state 5$^{2}S_{1/2}$ (Tiwari V B \textit{et al} 2008 {\it Phys. Rev.} A {\bf 78} 063421). Two steady state $\Lambda$-type systems of hyperfine energy levels are investigated using probe transitions into the levels F$^{\prime}$ = 2 and F$^{\prime}$ = 3 of the excited state 5$^{2}P_{3/2}$ in the presence of coupling transitions F = 3 $\to$ F$^{\prime}$ = 2 and F = 3 $\to$ F$^{\prime}$ = 3, respectively. The effects of uncoupled magnetic sublevel transitions and coupling field's Rabi frequency on the EIT signal from these systems are studied using a simple theoretical model.Comment: 12 pages, 7 figure

Comparison of capillary based microflurometric assay for CD4+ T cell count estimation with dual platform Flow cytometry

The CD4+ T cell count estimation is an important monitoring tool for HIV disease progression and efficacy of anti-retroviral treatment (ART). Due to availability of ART at low cost in developing countries, quest for reliable cost effective alternative methods for CD4+ T cell count estimation has gained importance. A simple capillary-based microflurometric assay (EasyCD4 System, Guava Technology) was compared with the conventional flow cytometric assay for estimation of CD4+ T cell counts in 79 HIV infected individuals. CD4+ T cell count estimation by both the assays showed strong correlation (r = 0.938, p < 0.001, 95% CI 0.90 to 0.96). The Bland Altman plot analysis showed that the limits of variation were within agreeable limits of ± 2SD (-161 to 129 cells/mm(3)). The Easy CD4 assay showed 100% sensitivity for estimating the CD4+ T cell counts < 200 cells/mm(3 )and < 350 cells/mm(3 )and 97% sensitivity to estimate CD4+ T cell count < 500 cells/mm(3). The specificity ranged from 82 to 100%. The Kappa factor ranged from 0.735 for the CD4+ T cell counts < 350 cells/mm(3 )to 0.771 for < 500 cells/mm(3 )CD4+ T cell counts. The system works with a simple protocol, is easy to maintain and has low running cost. The system is compact and generates minimum amount of waste. Hence the EasyCD4 System could be applied for estimation of CD4+ T cell counts in resource poor settings

Epidemic hepatitis E: serological evidence for lack of intrafamilial spread

To understand the dynamics of intrafamilial spread of the hepatitis E virus a study was conducted using blood samples collected during the 1988 and 1989 epidemics of viral hepatitis in Kudal and Atit villages of Maharashtra state, India; the epidemics were subsequently shown to be due to hepatitis E virus (HEV). The one-time collection carried out at the end of the Kudal epidemic was from 184 apparently healthy individuals irrespective of family history of jaundice during the epidemic. In the Atit epidemic, 153 family contacts of 49 IgM anti-HEV positive patients were bled. An additional 151 blood samples were collected from apparently healthy individuals irrespective of family history of jaundice during the epidemic. One month later, blood samples were collected from 64 of the 153 family contacts. Relevant history was recorded each time. All serum samples were tested for ALT levels and for IgM and IgG antibodies to hepatitis E virus employing ELISA. IgM anti-HEV positivity among persons with family history of jaundice was not different from those without such a history (8/62 (12.9%) and 11/122 (9%) at Kudal; 9/57 (15.8%) and 22/94 (23.4%) at Atit; P > 0.1). Excluding IgG anti-HEV positive samples from the analysis also yielded non-significant results. Of the 32 follow-up samples collected from family contacts without IgG or IgM antibodies to HEV in the initial blood sample, 31 remained IgM and IgG anti-HEV negative at the end of 1 month. One of the family contacts was found to be IgG anti-HEV positive in the second blood sample. The disease was not related to the index case. Intrafamilial spread of HEV is negligible

Differential placental methylation and expression of VEGF, FLT-1 and KDR genes in human term and preterm preeclampsia

BACKGROUND: Preeclampsia, a pregnancy complication of placental origin is associated with altered expression of angiogenic factors and their receptors. Recently, there is considerable interest in understanding the role of adverse intrauterine conditions in placental dysfunction and adverse pregnancy outcomes. Since we have observed changes in placental global DNA methylation levels in preeclampsia, this study was undertaken to examine gene promoter CpG methylation and expression of several angiogenic genes. We recruited 139 women comprising, 46 normotensive women with term delivery (≥37 weeks), 45 women with preeclampsia delivering preterm (<37 weeks) and 48 women with preeclampsia delivering at term. Expression levels and promoter CpG methylation of VEGF, FLT-1 and KDR genes in placentae from respective groups were determined by Taqman-based quantitative real time PCR and by the Sequenom® EpiTYPER™ technology respectively. RESULTS: We observed several differentially methylated CpG sites in the promoter regions of VEGF, FLT-1 and KDR between the normotensive and preeclampsia groups. We specifically observed hypomethylated CpGs in the promoter region and an increased expression of VEGF gene between term and preterm preeclampsia. However, mean promoter CpG methylation could not account for the higher expression of FLT-1 and KDR in preterm preeclampsia as compared to normotensive group. CONCLUSIONS: Our data indicates altered DNA methylation patterns in the VEGF, FLT-1 and KDR genes in preeclampsia as compared to the normotensive group, which could be involved in the pathophysiology of preeclampsia. Hypomethylation of VEGF promoter and consequent upregulation of VEGF mRNA levels could be a compensatory mechanism to restore normal angiogenesis and blood flow in preterm preeclampsia. This study suggests a role of altered DNA methylation in placental angiogenesis and in determining adverse pregnancy outcomes

Few cycle dynamics of multiphoton double ionization

In intense field ionization, an electron removed from the atomic core oscillates in the combined fields of the laser and the parent ion. This oscillation forces repeated revivals of its spatial correlation with the bound electrons. The total probability of double ionization depends on the number of returns and therefore on the number of optical periods in the laser pulse. We observed the yield of Ne\ub2\u207a relative to Ne\u207a with 12 fs pulses to be clearly less compared to 50 fs pulses in qualitative agreement with our theoretical model.Peer reviewed: YesNRC publication: Ye