Off Resonant Pumping for Transition from Continuous to Discrete Spectrum and Quantum Revivals in Systems in Coherent States

We show that in parametrically driven systems and, more generally, in systems in coherent states, off-resonant pumping can cause a transition from a continuum energy spectrum of the system to a discrete one, and result in quantum revivals of the initial state. The mechanism responsible for quantum revivals in the present case is different from that in the non-linear wavepacket dynamics of systems such as Rydberg atoms. We interpret the reported phenomena as an optical analog of Bloch oscillations realized in Fock space and propose a feasible scheme for inducing Bloch oscillations in trapped ions.Comment: 5 pages, 4 figures, submitted to Jnl. of Optics

Suppression of auxin stimulated growth of barley coleoptile sections by endosulfan

Endosulfan, a cyclic sulphurous acid ester commonly used as a broad spectrum insecticide, suppressed the elongation of barley coleoptiles. Indoleacetic acid at optimum concentration overcame the inhibition of growth of coleoptiles treated with 10 ppm endosulfan. However, perfusion of the coleoptile sections with endosulfan and subsequent treatment with indoleacetic acid could not stimulate cell elongation to the extent observed in the control

Effect of triple drug antiretroviral therapy on CD4+ count in pregnant women with HIV and prevention of parent to child transmission

Background: India has moved from single drug Antiretroviral Therapy (ART) in 2002 to triple drug ART in 2013 to prevent parent to child transmission of HIV. The aim of the study was to know the effects of triple drug ART on maternal CD4+ count and prevention of HIV transmission to baby along with its adherence, side effects and pregnancy outcome.Methods: A prospective study wsas done in Safdarjung Hospital, New Delhi on 40 HIV positive pregnant women who received single dose combination of triple drug ART. CD4+ count, LFT and KFT were done before beginning of ART and repeated after 6 months of ART. The infants received nevirapine prophylaxis and HIV status was determined by DBS PCR at 6 weeks.Results: The median CD4+ count was 317 and 397 pre and post ART for 6 months respectively (p value<0.001. Low birth weight (LBW) was seen in 43.59% which was statistically significant but confounded as 76.4% of these babies were preterm. 23.08% of babies had an APGAR of < 7 at 1 minute, out of which 77.7% were preterm. Nine out of 39 infants (one had abortion) needed NICU admission. Only one baby (2.56%) was HIV positive who died at 4 months of age due to pneumonia. There was no defaulter and no statistically significant changes in LFT and KFT after 6 months of ART.Conclusions: Triple drug ART offers greater convenience improves fetomaternal outcome and minimize the risk of HIV transmission from mother to child

Cytokine cascade in dengue hemorrhagic fever: implications for pathogenesis

Dengue virus produces a mild acute febrile illness, dengue fever (DF) and a severe illness, dengue hemorrhagic fever (DHF). The characteristic feature of DHF is increased capillary permeability leading to extensive plasma leakage in serous cavities resulting in shock. The pathogenesis of DHF is not fully understood. This paper presents a cascade of cytokines, that in our view, may lead to DHF. The main feature is the early generation of a unique cytokine, human cytotoxic factor (hCF) that initiates a series of events leading to a shift from Th1-type response in mild illness to a Th2-type response resulting in severe DHF. The shift from Th1 to Th2 is regulated by the relative levels of interferon-gamma and interleukin (IL)-10 and between IL-12 and transforming growth factor-β , which showed an inverse relationship in patients with DF

Elevated levels of interleukin-13 and IL-18 in patients with dengue hemorrhagic fever

Interleukin (IL)-13 is produced by T helper 2 (Th2)-type cells and inhibits the production of proinflammatory cytokines by activated monocytes, while IL-18 is a pleiotropic cytokine that induces interferon-&#947; and plays an important role in the development of Th1-type cells. Role of the shift from a Th1-type response to Th2-type has been suggested in the pathogenesis of dengue hemorrhagic fever (DHF). This study was undertaken to investigate the possible protective/pathogenic role of IL-13 and IL-18 in patients with DHF. Sera were collected from a total of 84 patients with various grades of dengue illness and 21 normal healthy controls and tested for IL-13 and IL-18 levels using commercial enzyme-linked immunosorbent assay kits. The results showed that very low levels of IL-13 (4&#177; 3 pg ml-1) and IL-18 (15&#177; 4 pg ml-1) were detected in the sera of healthy controls. In dengue patients, the levels of IL-13 and IL-18 were the highest in the patients with DHF grade IV (205&#177; 103 pg ml-1 and 366&#177; 155 pg ml-1, respectively) and the lowest in patients with dengue fever (22&#177; 12 pg ml-1 and 76&#177; 50 pg ml-1, respectively). Both the cytokines appeared (IL-13=20&#177; 11 pg ml-1 and IL-18=70&#177; 45 pg ml-1) during the first 4 days of illness and reached peak levels (IL-13=204&#177; 96 pg ml-1 and IL-18=360&#177; 148 pg ml-1) by day 9 onwards. The presence of high levels of IL-13 and IL-18 during severe illness and late phases of the disease suggests that both of these cytokines may contribute to the shift from a Th1- to Th2-type response and thus to the pathogenesis of DHF

Cytotoxic factor-autoantibodies: possible role in the pathogenesis of dengue haemorrhagic fever

During dengue virus infection a unique cytokine, cytotoxic factor (hCF), is produced that is pathogenesis-related and plays a key role in the development of dengue haemorrhagic fever (DHF). However, what regulates the adverse effects of hCF is not known. We have previously shown that anti-hCF antibodies raised in mice, neutralise the pathogenic effects of hCF. In this study we have investigated the presence and levels of hCF-autoantibodies in sera of patients with various severity of dengue illness (n=136) and normal healthy controls (n=50). The highest levels of hCF-autoantibodies (mean&#177; S.D.=36&#177; 20 U ml-1) were seen in patients with mild illness, the dengue fever (DF), and 48 out of 50 (96%) of the sera were positive. On the other hand the hCF-autoantibody levels declined sharply with the development of DHF and the levels were lowest in patients with DHF grade IV (mean &#177; S.D.=5&#177; 2 U ml-1; P=&lt;0.001 as compared to DF). Only one of the 13 DHF grade IV patients had an antibody level above the 'cut-off' value (mean plus 3 S.D. of the control sera). The analysis of data with respect to different days of illness further showed that the highest levels of hCF-autoantibodies were present in DF patients at &gt;9 days of illness. Moreover, the DF patients at all time points, i.e. 1-4, 5-8 and &gt;9 days of illness had significantly higher levels of hCF-autoantibodies (P&lt;0.001) than patients with DHF grade I, II, III and IV. In addition DHF grade I and grade II patients had significantly more positive specimens than DHF grade III and grade IV patients at all time points. These results suggest that elevated levels of hCF-autoantibodies protect the patients against the development of severe forms of DHF and, therefore, it may be useful as a prognostic indicator

Cytotoxic factor in dengue haemorrhagic fever

Objective: Cytotoxic factor is a unique pathogenesis-associated cytokine that is produced in mice (mCF) and man (hCF) during dengue virus infection. This study was undertaken to investigate the prevalence of hCF and its relationship to the duration and severity of the illness, and to ascertain its role, if any, in the pathogenesis of dengue fever (DF) and dengue haemorrhagic fever (DHF). Methods: Peripheral venous blood was collected from the patients of various grades and on different days after the onset of clinical illness. Sera were collected from a total of 333 cases, and analysed for the presence of hCF by inhibition ELISA and dot blot tests. Result: The positivity for hCF was 100% in cases of DHF grades III and IV, while overall positivity was seen in 295 out of 333 (88%) cases studied. Sera collected from the 1st to the 20th day of illness were positive for hCF. This was not seen at later periods. A majority of cases (52%) were below 15 years of age and peak positivity of 96% was noticed in the age-group of 11-15 years. The mean inhibition value of the ELISA was lowest (40 ± 8%) in cases of DF and was highest (70 ± 10%) in DHF grade IV, and the peak titres were found on the first 4 days of the illness. Conclusion: The findings show the presence of hCF in the majority of cases. It is detectable up to the 20th day of illness and may suggest an association of higher levels of hCF with the onset and severity of the illness

Entanglement by linear SU(2) transformations: generation and evolution of quantum vortex states

We consider the evolution of a two-mode system of bosons under the action of a Hamiltonian that generates linear SU(2) transformations. The Hamiltonian is generic in that it represents a host of entanglement mechanisms, which can thus be treated in a unified way. We start by solving the quantum dynamics analytically when the system is initially in a Fock state. We show how the two modes get entangled by evolution to produce a coherent superposition of vortex states in general, and a single vortex state under certain conditions. The degree of entanglement between the modes is measured by finding the explicit analytical dependence of the Von Neumann entropy on the system parameters. The reduced state of each mode is analyzed by means of its correlation function and spatial coherence function. Remarkably, our analysis is shown to be equally as valid for a variety of initial states that can be prepared from a two-mode Fock state via a unitary transformation and for which the results can be obtained by mere inspection of the corresponding results for an initial Fock state. As an example, we consider a quantum vortex as the initial state and also find conditions for its revival and charge conjugation. While studying the evolution of the initial vortex state, we have encountered and explained an interesting situation in which the entropy of the system does not evolve whereas its wave function does. Although the modal concept has been used throughout the paper, it is important to note that the theory is equally applicable for a two-particle system in which each particle is represented by its bosonic creation and annihilation operators.Comment: 6 figure

Quantum State Tomography of Complex Multimode Fields using Array Detectors

We demonstrate that it is possible to use the balanced homodyning with array detectors to measure the quantum state of correlated two-mode signal field. We show the applicability of the method to fields with complex mode functions, thus generalizing the work of Beck (Phys. Rev. Letts. 84, 5748 (2000)) in several important ways. We further establish that, under suitable conditions, array detector measurements from one of the two outputs is sufficient to determine the quantum state of signals. We show the power of the method by reconstructing a truncated Perelomov state which exhibits complicated structure in the joint probability density for the quadratures.Comment: 14 pages text and 3 figures. To be submitted to PR