Malaria rapid diagnostic test performance: Results of WHO product testing of malaria RDTs: Round 6 (2014-2015)

Overview This report, published in conjunction with a summary overview of results of rounds 1–6, is the sixth in a series of laboratory-based evaluations of rapid diagnostic tests (RDTs) for malaria. It provides a comparative measure of their performance in a standardized way to distinguish between well and poorly performing tests. It can be used by malaria control programmes and guide WHO procurement recommendations for these diagnostic tools. The evaluation reported here was a joint project of the WHO Global Malaria Programme, the Foundation for Innovative New Diagnostics (FIND) and the United States Centers for Disease Control and Prevention (CDC) within the WHO-FIND Malaria RDT Evaluation Programme. The project was financed by FIND through a grant from UNITAID.

A novel fibre-coated sorbent for rapid removal of heavy metals from wastewater. Sorption of Zinc(II) from dilute aqueous solutions in the presence of high concentrations of common salts

The commercial acrylic fibre "Cashmilon" was partially hydrolyzed to convert a fraction of its nitrile (-CN) groups to carboxylic acid (-COOH) groups and then coated with polyethylenimine (PEI) resin and cross-linked with glutaraldehyde to produce a novel gel-coated fibrous sorbent with multiple functionalities of cationic, anionic and chelating types, and significantly faster sorption kinetics than bead-form sorbents. The sorption properties of the fibrous sorbent were measured using Zn(II) in aqueous solution as the sorbate to determine the effects of pH and the presence of common ions in the solution on the sorption capacity. The rate of sorption on the gel-coated fibre was measured in comparison with that on Amberlite IRA-68 weak-base resin beads, to demonstrate the marked difference between fibre and bead-form sorbents in their kinetic behaviour.

RACK: RApid Clustering using K-means algorithm

The k-means algorithm is an extremely popular technique for clustering data. One of the major limitations of the k-means is that the time to cluster a given dataset D is linear in the number of clusters, k. In this paper, we employ height balanced trees to address this issue. Specifically, we make two major contributions, (a) we propose an algorithm, RACK (acronym for RApid Clustering using k-means), which takes time favorably comparable with the fastest known existing techniques, and (b) we prove an expected bound on the quality of clustering achieved using RACK. Our experimental results on large datasets strongly suggest that RACK is competitive with the k-means algorithm in terms of quality of clustering, while taking significantly less time.

A new approach for simple and rapid shape measurement of objects with surface discontinuities

A new approach for unwrapping phase maps, obtained during the measurement of 3-D surfaces using sinusoidal structured light projection technique, is proposed. "Takeda's method" is used to obtain the wrapped phase map. Proposed method of unwrapping makes use of an additional image of the object captured under the illumination of a specifically designed color-coded pattern. The new approach demonstrates, for the first time, a method of producing reliable unwrapping of objects even with surface discontinuities from a single-phase map. It is shown to be significantly faster and reliable than temporal phase unwrapping procedure that uses a complete exponential sequence. For example, if a measurement with the accuracy obtained by interrogating the object with S fringes in the projected pattern is carried out with both the methods, new method requires only 2 frames as compared to (log(2)S +1) frames required by the later method.

A simple and rapid method for quantification of hapten specific antibodies

A sensitive and simple method for quantification of antibodies against small molecules is described using DNP-lysozyme as the enzyme conjugate. The anti-DNP antiserum was raised against DNP-bovin serum albumin conjugate. Anti-DNP antibody or its monovalent fragment (Fab) reduced the enzyme activity of DNP-lysozyme conjugate in a concentration-dependent manner. The inhibition of enzyme activity is a specific measure of the antibody and Fab content of the sample. The specificity of the reaction was assessed by reduction of antibody-induced inhibition by DNP-lysine. The ability of DNP-lysine to reduce the antibody-induced inhibition of DNP-lysozyme activity also makes possible a sensitive assay for DNP-lysine.

A novel fibre-coated sorbent for rapid removal of heavy metals from wastewater. Sorption of Zinc(II) from dilute aqueous solutions in the presence of high concentrations of common salts

The commercial acrylic fibre "Cashmilon" was partially hydrolyzed to convert a fraction of its nitrile (-CN) groups to carboxylic acid (-COOH) groups and then coated with polyethylenimine (PEI) resin and cross-linked with glutaraldehyde to produce a novel gel-coated fibrous sorbent with multiple functionalities of cationic, anionic and chelating types, and significantly faster sorption kinetics than bead-form sorbents. The sorption properties of the fibrous sorbent were measured using Zn(II) in aqueous solution as the sorbate to determine the effects of pH and the presence of common ions in the solution on the sorption capacity. The rate of sorption on the gel-coated fibre was measured in comparison with that on Amberlite IRA-68 weak-base resin beads, to demonstrate the marked difference between fibre and bead-form sorbents in their kinetic behaviour.

Rapid growth of nanotubes and nanorods of wurtzite ZnO through microwave-irradiation of a metalorganic complex of zinc and a surfactant in solution

Large quantities of single-crystalline ZnO nanorods and nanotubes have been prepared by the microwave, irradiation of a metalorganic complex of zinc, in the presence of a surfactant. The method is simple, fast, and inexpensive (as it uses a domestic microwave oven), and yields pure nanostructures of the hexagonal wurtzite phase of ZnO in min, and requires no conventional templating. The ZnO nanotubes formed have a hollow core with inner diameter varying from 140-160 nm and a wall of thickness, 40-50 nm. The length of nanorods and nanotubes varies in the narrow range of 500-600 nm. These nanostructures have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The ZnO nanorods and nanotubes are found by SAED to be single-crystalline. The growth process of ZnO nanorods and nanotubes has been investigated by varying the surfactant concentration and microwave irradiation time. Based on the various results obtained, a tentative and plausible mechanism for the formation of ZnO nanostructures is proposed.

New phase unwrapping strategy for rapid and dense 3D data acquisition in structured light approach

Sinusoidal structured light projection (SSLP) technique, specifically-phase stepping method, is in widespread use to obtain accurate, dense 3-D data. But, if the object under investigation possesses surface discontinuities, phase unwrapping (an intermediate step in SSLP) stage mandatorily require several additional images, of the object with projected fringes (of different spatial frequencies), as input to generate a reliable 3D shape. On the other hand, Color-coded structured light projection (CSLP) technique is known to require a single image as in put, but generates sparse 3D data. Thus we propose the use of CSLP in conjunction with SSLP to obtain dense 3D data with minimum number of images as input. This approach is shown to be significantly faster and reliable than temporal phase unwrapping procedure that uses a complete exponential sequence. For example, if a measurement with the accuracy obtained by interrogating the object with 32 fringes in the projected pattern is carried out with both the methods, new strategy proposed requires only 5 frames as compared to 24 frames required by the later method.

Electron-beam melting and centrifugal splat-quenching technique for rapid solidification of titanium alloys

An electron-beam melting and centrifugal splat-quenching technique for the production of microflakes of Ti-6A1-4V (wt%) alloy quenched at an average cooling rate of about 105 K sec–1 is described. The effect of substrate angle on the shape, size, microstructure and average cooling rate of the flakes of major sieve fractions is discussed. Morphologies of particles of minor sieve fractions are dealt with briefly.

Rapid localization of damage using a circular sensor array and Lamb wave based triangulation

A damage detection and imaging methodology based on symmetry of neighborhood sensor path and similarity of signal patterns with respect to radial paths in a circular array of sensors has been developed It uses information regarding Limb wave propagation along with a triangulation scheme to rapidly locate and quantify the severity of damage without using all of the sensor data. In a plate like structure, such a scheme can be effectively employed besides full field imaging of wave scattering pattern from the damage, if present in the plate. This new scheme is validated experimentally. Hole and corrosion type damages have been detected and quantified using the proposed scheme successfully. A wavelet based cumulative damage index has been studied which shows monotonic sensitivity against the severity of the damage. which is most desired in a Structural Health Monitoring system. (C) 2010 Elsevier Ltd. All rights reserved.

Rapid isolation of lysyl-tRNA synthetase from rat liver

The high molecular weight aminoacyl-tRNA synthetase complex (the 24S complex) was isolated from rat liver by ultracentrifugation. The lysyl-tRNA synthetase (E.C. 6.1.1.6) was selectively dissociated by hydrophobic interaction chromatography on 1,6 diaminohexyl agarose followed by hydroxylapatite chromatography and DEAE chromatography. The lysyl-tRNA synthetase dissociated from the 24S synthetase complex was purified approximately to 2700 fold with 14% yield.

A Rapid Bioassay for Measuring Inhibin Activity

A sensitive and rapid bioassay of inhibin is described. Swiss albino female mice, 27 days old, weighing 25-30 g, were primed with 20 IU hCG, given in 2 equal doses, administered at 0900 h and 1800 h. An increment of 200% in uterine weight could be observed when the animals were autopsied the next day at 1000 h. The validity of the endpoint chosen, as a function dependent on FSH, was shown by the fact that neutralization of endogenous FSH by FSH antiserum led to an inhibition of uterine weight increase. Further injection of the inhibin material caused an actual reduction in the heightened levels of FSH (ng/ml) brought about by hCG: Control, 207 ± 13.6; hCG, 365 ± 28.8 and hCG inhibin, below the detection level of radioimmunoassay. Inhibin preparation from ovine testicular extract when tested at 3 dose levels showed a dose dependent and significant suppression in uterine weight increase. The assay was statistically validε = 2.5; slope = 23.9; λ = 0.104 and intra- and interassay variation = 8.3% and 11.7%, respectively. Since the mouse uterine weight assay is specific, has greater sensitivity and is uniformly reproducible, it is suggested that this assay procedure is ideally suited to assess the activity of different inhibin test preparations as well as to follow the purification of inhibin activity from crude material.

Rapid synthesis of room temperature ferromagnetic Ag-doped LaMnO3 perovskite phases by the solution combustion method

We report the rapid solution combustion synthesis and characterization of Ag-substituted LaMnO3 phases at relatively low temperature using oxalyl dihydrazide, as fuel. Structural parameters were refined by the Rietveld method using powder X-ray diffraction data. While the parent LaMnO3 crystallizes in the orthorhombic structure, the Ag-substituted compounds crystallize in the rhombohedral symmetry. On increasing Ag-content, unit cell volume and Mn-O-Mn bond angle decreases. The Fourier transform infra red spectrum shows two absorption bands corresponding to Mn-O stretching vibration (v(s) mode) and Mn-O-Mn deformation vibration (v(b) mode) around 600 cm(-1) and 400 cm(-1) for the compositions x = 0.0, 0.05 and 0.10, respectively. Electrical resistivity measurements reveal that composition-controlled metal to insulator transition, with the maximum metal to insulator being 280 K for the composition La0.75Ag0.25MnO3. Increase in magnetic moment was observed with increase in Ag-content. The maximum magnetic moment of 35 emu/g was observed for the composition La0.80Ag0.20MnO3. (C) 2010 Elsevier Ltd. All rights reserved.