Significant decrease of the enhancement/neutralization index in HIV patients during highly active antiretroviral therapy (HAART)

Authors studied the effect of highly active antiretroviral therapy (HAART) on balance of the antibodies that enhance or neutralize growth of HIV-1 IIIB strain in MT-4 cells in the presence or absence of human complement. Sequential serum samples were collected from 28 patients in advanced stage of HIV disease before and during HAART. The balance of the enhancing and neutralizing antibodies was expressed by an index value (E/N I). Samples with an E/N I of 2.0 (twofold increase in virus production) were considered as enhancing. At the beginning of HAART serum samples from eight patients enhanced, and samples from only two patients neutralized the virus in the presence of complement, median (25th-75th percentile) value of E/N I was 1.32 (0.79-2.29). E/N I significantly (P<0.0001) dropped to 0.37 (0.19-0.57) during the follow-up period of 18.5 (10.5-23.5) months under HAART. Similar changes were detected when serum samples were tested with no complement added. The E/N I values were also markedly decreased when cultures inoculated with mixtures of HIV and purified IgG prepared from serum pools taken before and during HAART, respectively, were compared. In the last samples of 20/28 patients, neutralization was measured even in the presence of complement while enhancement was found with none of these samples. These findings suggest that HAART results in disappearance of enhancing antibodies and switches the E/N I toward neutralization. © 2003 Elsevier Science B.V. All rights reserved

Composites of ion-in-conjugation polysquaraine and SWCNTs for the detection of H2S and NH3 at ppb concentrations

Abstract Several different methods are established for the analysis of gases, including optical spectroscopy, photoacoustic spectroscopy as well as colorimetric and resistive sensing, the measurements systems are either too complex or have limited sensitivity. In particular, when the goal is to apply a large number of sensors in networks, it is highly desirable to have devices that are simple, have low cost and energy consumption, yet sensitive and selective to monitor analytes even in traces. Herein, we propose a new type of resistive sensor device based on a composite of single-wall carbon nanotubes and an ion-in-conjugation polymer, poly(1,5-diaminonaphthalene-squaraine), capable of detecting H2S and NH3 in air even at room temperature with a theoretical concentration limit of ∼1 ppb and ∼7 ppb, respectively. Density functional theory calculations revealed that H atoms of the analytes and O atoms of the polymer chain interact and form hydrogen bonds, and the electron withdrawal from the gas molecules by the polymer chain results in the change of its electrical conductivity. To demonstrate the feasibility of the new nanocomposites in sensing, we show the devices for monitoring food safety with good sensor stability of operation for at least 3 months of period of time

Tectonically controlled Quaternary intracontinental fluvial sequence development in the Nyírség–Pannonian Basin, Hungary

The Quaternary fluvial succession of the Nyírség (NE Hungary), a proximal sub-basin of 4000 km2 in the intracontinental Pannonian Basin, was studied based on log facies analysis. Regional mapping of sequences was established by analysis of fully cored boreholes and high scale local correlations in densely drilled areas. The age of the sequences was determined by correlating the magnetic susceptibility (MS) record of the fully cored boreholes with that of the reference Hungarian boreholes dated paleomagnetically (Dévaványa-1 and Vésztő-1 in Cooke et al., 1979). To give the Hungarian data global perspective they were correlated to the MS curve of the Chinese Loess (Ding et al., 2005) that are in turn correlated with the Marine Isotope Record (Lisiecki and Raymo, 2005 and Gibbard and Cohen, 2008). The ages of the mapped sequence boundaries are 2.62, 2.26, 2.12, 1.22, 1.04, 0.58 and 0.34 Ma respectively and can be related to the transitions from cool to warm conditions. Regional unconformities at 2.26–2.12, 1.22 and 0.58 Ma also coincide with activity maxima of the radiometrically dated Quaternary volcanism. This high frequency of climatically controlled erosive sequence boundaries in the structurally active periods indicates that the sedimentary record of climatic erosion is better expressed in times when structural changes generate instability in the drainage network. The occurrence of packages of regional unconformities in relation to volcanic activity enables the geochronological dating of episodes in the Quaternary compression of the Carpathian–Pannonian region. The role of tectonic control on the climatically induced changes in the drainage network has been explained by a structural development model based on seismic, gravity and magnetic data. The changes in the local paleohydrology were triggered by a compression related elevation of the basement and the associated occurrence of a local transtension-related subsidence

Portable cyber-physical system for indoor and outdoor gas sensing

Abstract A design, development and testing process for a cyber-physical system capable of versatile gas sensor measurement is described. Two approaches for the system are proposed; a stationary system for calibration and testing in laboratory environments and a portable system with wireless capability. The device utilizes a well-established Arduino microcontroller as well as a Raspberry Pi single board computer. The functionality is realized with C and Python programming languages. The operability is validated by system performance evaluation in the mixture of air and hydrogen gas, using both commercial and experimental Taguchi-type metal oxide semiconductor sensors. The experimental sensors are fabricated by inkjet printing platinum decorated tungsten oxide nanoparticles onto an electrode pattern on a silicon substrate which is then wire bonded to a chip carrier. The measurement platform demonstrated in our paper provides rapid prototyping capabilities for evaluating novel gas sensor materials in realistic measurement scenarios

Size-dependent H₂ sensing over supported Pt nanoparticles

Abstract Catalyst size affects the overall kinetics and mechanism of almost all heterogeneous chemical reactions. Since the functional sensing materials in resistive chemical sensors are practically the very same nanomaterials as the catalysts in heterogeneous chemistry, a plausible question arises: Is there any effect of the catalyst size on the sensor properties? Our study attempts to give an insight into the problem by analyzing the response and sensitivity of resistive H₂ sensors based on WO₃ nanowire supported Pt nanoparticles having size of 1.5±0.4 nm, 6.2±0.8 nm, 3.7±0.5 nm and 8.3±1.3 nm. The results show that Pt nanoparticles of larger size are more active in H₂ sensing than their smaller counterparts and indicate that the detection mechanism is more complex than just considering the number of surface atoms of the catalyst