Uptake of purines in <i>Plasmodium falciparum</i>-infected human erythrocytes is mostly mediated by the human Equilibrative Nucleoside Transporter and the human Facilitative Nucleobase Transporter

&lt;b&gt;Background&lt;/b&gt;: Plasmodium parasites are unable to synthesize purines de novo and have to salvage them from the host. Due to this limitation in the parasite, purine transporters have been an area of focus in the search for anti-malarial drugs. Although the uptake of purines through the human equilibrative nucleoside transporter (hENT1), the human facilitative nucleobase transporter (hFNT1) and the parasite-induced new permeation pathway (NPP) has been studied, no information appears to exist on the relative contribution of these three transporters to the uptake of adenosine and hypoxanthine. Using the appropriate transporter inhibitors, the role of each of these salvage pathways to the overall purine transport in intraerythrocytic Plasmodium falciparum was systematically investigated. &lt;b&gt;Methods&lt;/b&gt;: The transport of adenosine, hypoxanthine and adenine into uninfected and P. falciparum-infected human erythrocytes was investigated in the presence or absence of classical inhibitors of the hFNT1, hENT1 and NPP. The effective inhibition of the various transporters by the classical inhibitors was verified using appropriate known substrates. The ability of high concentration of unlabelled substrates to saturate these transporters was also studied. &lt;b&gt;Results&lt;/b&gt;: Transport of exogenous purine into infected or uninfected erythrocytes occurred primarily through saturable transporters rather than through the NPP. Hypoxanthine and adenine appeared to enter erythrocytes mainly through the hFNT1 nucleobase transporter whereas adenosine entered predominantly through the hENT1 nucleoside transporter. The rate of purine uptake was approximately doubled in infected cells compared to uninfected erythrocytes. In addition, it was found that the rate of adenosine uptake was considerably higher than the rate of hypoxanthine uptake in infected human red blood cells (RBC). It was also demonstrated that furosemide inhibited the transport of purine bases through hFNT1. &lt;b&gt;Conclusion&lt;/b&gt;: Collectively, the data obtained in this study clearly show that the endogenous host erythrocyte transporters hENT1 and hFNT1, rather than the NPP, are the major route of entry of purine into parasitized RBC. Inhibitors of hENT1 and hFNT1, as well as the NPP, should be considered in the development of anti-malarials targeted to purine transport

Reply to "Comment on Renormalization group picture of the Lifshitz critical behaviors"

We reply to a recent comment by Diehl and Shpot (cond-mat/0305131) criticizing a new approach to the Lifshitz critical behavior just presented (M. M. Leite Phys. Rev. B 67, 104415(2003)). We show that this approach is free of inconsistencies in the ultraviolet regime. We recall that the orthogonal approximation employed to solve arbitrary loop diagrams worked out at the criticized paper even at three-loop level is consistent with homogeneity for arbitrary loop momenta. We show that the criticism is incorrect.Comment: RevTex, 6 page

Induction methods used in low temperature physics

A study has been made of induction bridges used in low temperature physics.\ud \ud In Part 1 the design of a mutual inductance bridge of the Hartshorn type is discussed. This design is based on a critical analysis of impurity effects of the different parts of the Hartshorn bridge. With this equipment frequencies up to 0.5 MHz can be used. Two methods have been developed to examine the secondary signal. In one of these use has been made of AD conversion techniques. In the other one, the secondary signal, produced by a superconducting sample, which is generally distorted, is analysed by using a Fourier expansion.\ud \ud In Part 2 equipment is described which enables us to measure the phase and amplitude of the harmonics of the output signal of the bridge. For synchronous detection a reference signal of the same frequency of the harmonic of interest is required. This reference signal is generated from the input signal of the bridge by means of a digital frequency multiplier with programmable multiplication factor N.\ud \ud In Part 3 some experimental results, showing the possibilities of the equipment, on some superconductors are presented

A loss-less superconducting kilo-oersted ac magnetic field system

A simple superconducting system which allows almost loss-less ac magnetic field to be generated in the kilo-oested region and in the frequency range from dc up to more than 1 kHz is described. The behaviour of commercially available superconducting wires and the influence of winding of the coils are also considered

Anomalous a.c. resistivity effect in Nb and Sn at high static fields in the liquid helium temperature range

The a.c. susceptibilities of Nb and Sn cylinders in the normal state at temperatures below T>c have been measured. The results cannot be described by the formalism of the classical skin-effect. Therefore a formal description is given

Cost-of-illness of rheumatoid arthritis and ankylosing spondylitis

OBJECTIVES:\ud To assess, quantify and summarise the cost of illness of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) from the societal perspective.\ud \ud METHODS:\ud Original studies reporting costs of RA or AS were searched systematically. Both cost-of-illness studies and economic evaluations of therapies were included. Studies were appraised for patient and study characteristics, type of costs and actual costs. Reported costs were aggregated by cost categories and overall mean costs were summarised by cost domain (healthcare, patient and family, and productivity costs).\ud \ud RESULTS:\ud Overall mean costs of RA (€14,906 per year) were above that of AS (€9,374 per year), while the relative distribution of costs over cost domains was approximately similar. For both diseases, productivity costs based on the human cost approach were 3 to 10 times higher than the friction costs and accounted for more than half the total costs of both diseases.\ud \ud CONCLUSIONS:\ud Productivity costs constitute the largest part of the total cost-off-illness of RA and AS reflecting the high burden of the disease on work participation. Although total and direct costs of illness in RA were higher than in AS, the average age of AS patients was 10 years lower and therefore, lifetime costs associated with AS may actually be equal or higher

Non-Riemannian vortex geometry of rotational viscous fluids and breaking of the acoustic Lorentz invariance

Acoustic torsion recently introduced in the literature (Garcia de Andrade,PRD(2004),7,64004) is extended to rotational incompressible viscous fluids represented by the generalised Navier-Stokes equation. The fluid background is compared with the Riemann-Cartan massless scalar wave equation, allowing for the generalization of Unruh acoustic metric in the form of acoustic torsion, expressed in terms of viscosity, velocity and vorticity of the fluid. In this work the background vorticity is nonvanishing but the perturbation of the flow is also rotational which avoids the problem of contamination of the irrotational perturbation by the background vorticity. The acoustic Lorentz invariance is shown to be broken due to the presence of acoustic torsion in strong analogy with the Riemann-Cartan gravitational case presented recently by Kostelecky (PRD 69,2004,105009). An example of analog gravity describing acoustic metric is given based on the teleparallel loop where the acoustic torsion is given by the Lense-Thirring rotation and the acoustic line element corresponds to the Lense-Thirring metric

Soil water balance and a water satisfaction index for mustard grown under dryland conditions

Non-Peer ReviewedMustard (Brassica juncea L. Coss) was grown under dry land condition in western Canada (near Saskatoon) and in southern Sri Lanka. Soil water balance for the cropping period was calculated , using data on climate, soil moisture, and root growth. Actual crop evapotranspiration was calculated and used to estimate water use efficiency for each location. A water Satisfaction Index was calculated based on cumulative deficit in water use during the crop growth. More rainfall but lower precipitation use efficiency was observed in tropical dry land conditions (rain-fed uplands) in comparison to conditions at Saskatoon. The soil water balance indicated higher dependence of crop growth on seasonal rainfall in tropical conditions and more efficient use of precipitation and water stored in the soil profile under conditions at Saskatoon. Constraints to efficient use of precipitation under tropical conditions will also be discussed

INNOVATION FOR A SUSTAINABLE BUILT ENVIRONMENT

Despite the indisputable contribution of innovations to socio-economic development, the world has realized that many innovations and technologies have been a major cause of climatic change and resource depletion. This research aimed to identify how and whether innovation in construction contributes to achieve a sustainable built environment. An analytical framework -derived from literature studies on evidence and theories on innovation in manufacturing-was applied in Dutch construction. The study underpinned that sustainable construction requires innovative solutions which go beyond the traditional and generally accepted way of building. Government support appeared necessary for a regime shift to stimulate innovation for a sustainable built environment. Policies thus should be directed to tackle a major bottleneck in construction: knowledge, expectations and beliefs concerning innovation for sustainable construction