Cube Root (cube + root)

Distribution by Scientific Domains

Selected Abstracts

Dissolution of artemisinin/polymer composite nanoparticles fabricated by evaporative precipitation of nanosuspension

Mitali Kakran
Abstract Objectives An evaporative precipitation of nanosuspension (EPN) method was used to fabricate composite particles of a poorly water-soluble antimalarial drug, artemisinin, with a hydrophilic polymer, polyethylene glycol (PEG), with the aim of enhancing the dissolution rate of artemisinin. We investigated the effect of polymer concentration on the physical, morphological and dissolution properties of the EPN-prepared artemisinin/PEG composites. Methods The original artemisinin powder, EPN-prepared artemisinin nanoparticles and artemisinin/PEG composites were characterised by scanning electron microscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD), dissolution testing and HPLC. The percentage dissolution efficiency, relative dissolution, time to 75% dissolution and mean dissolution time were calculated. The experimental drug dissolution data were fitted to various mathematical models (Weibull, first-order, Korsemeyer,Peppas, Hixson,Crowell cube root and Higuchi models) in order to analyse the release mechanism. Key findings The DSC and XRD studies suggest that the crystallinity of the EPN-prepared artemisinin decreased with increasing polymer concentration. The phase-solubility studies revealed an AL -type curve, indicating a linear increase in drug solubility with PEG concentration. The dissolution rate of the EPN-prepared artemisinin and artemisinin/PEG composites increased markedly compared with the original artemisinin powder. Conclusions EPN can be used to prepare artemisinin nanoparticles and artemisinin/PEG composite particles that have a significantly enhanced dissolution rate. The mechanism of drug release involved diffusion and erosion. [source]

A quantitative method for measuring the mass concentration of the filamentous bacterium Type 021N in activated sludge using fluorescence in situ hybridization

Y. Guan
Abstract Aims: This study aimed to develop a quantitative method for measuring mass concentrations of Type 021N, a bacterium causing bulking in activated sludge. Methods and Results: Fluorescence in situ hybridization was used to determine the relationship between the concentration ratio of the mass of the bacterium Type 021N to mass of activated sludge, and the proportion of fluorescence area imparted by probe G123T specific for Type 021N to that obtained with probe EUB338 for bacteria. A linear relationship existed between the cube root of the mass concentration ratio and square root of this area proportion. Conclusions: A standard curve was obtained for quantifying Type 021N in activated sludge. Significance and Impact of the Study: This method may allow the determination of growth rate constant of filamentous bacteria in activated sludge, information that will help in understanding their ecology. [source]

Aspects of achondroplasia in the skulls of dwarf transgenic mice: A cephalometric study

Melissa Wadler Bloom
Abstract Achondroplasia, the most common short-limbed dwarfism in humans, results from a single nucleotide substitution in the gene for fibroblast growth factor receptor 3 (FGFR3). FGFR3 regulates bone growth in part via the mitogen-activated protein kinase pathway (MAPK). To examine the role of this pathway in chondrocyte differentiation, a transgenic mouse was generated that expresses a constitutively active mutant of MEK1 in chondrocytes and exhibits dwarfing characteristics typical of human achondroplasia, i.e., shortened axial and appendicular skeletons, mid-facial hypoplasia, and dome-shaped cranium. In this study, cephalometrics of the MEK1 mutant skulls were assessed to determine if the MEK1 mice are a good model of achondroplasia. Skull length, arc of the cranial vault, and area, maximum and minimum diameters of the brain case were measured on digitized radiographs of skulls of MEK1 and control mice. Cranial base and nasal bone length and foramen magnum diameter were measured on midsagittal micro-CT sections. Data were normalized by dividing by the cube root of each animal's weight. Transgenic mice exhibited a domed skull, deficient midface, and (relatively) prognathic mandible and had a shorter cranial base and nasal bone than the wild-type. Skull length was significantly less in transgenic mice, but cranial arc was significantly greater. The brain case was larger and more circular and minimum diameter of the brain case was significantly greater in transgenic mice. The foramen magnum was displaced anteriorly but not narrowed. MEK1 mouse cephalometrics confirm these mice as a model for achondroplasia, demonstrating that the MAP kinase signaling pathway is involved in FGF signaling in skeletal development. 2006 Wiley-Liss, Inc. [source]

DIBER: protein, DNA or both?

Grzegorz Chojnowski
The program DIBER (an acronym for DNA and FIBER) requires only native diffraction data to predict whether a crystal contains protein, B-form DNA or both. In standalone mode, the classification is based on the cube root of the reciprocal unit-cell volume and the largest local average of diffraction intensities at 3.4, resolution. In combined mode, the Phaser rotation-function score (for the 3.4, shell and a canonical B-DNA search model) is also taken into account. In standalone (combined) mode, DIBER classifies 87.4 0.2% (90.2 0.3%) of protein, 69.1 0.3% (78.8 0.3%) of protein,DNA and 92.7 0.2% (90.0 0.2%) of DNA crystals correctly. Reliable predictions with a correct classification rate above 80% are possible for 36.8 1.0% (60.2 0.4%) of the protein, 43.6 0.5% (59.8 0.3%) of the protein,DNA and 83.3 0.3% (82.6 0.4%) of the DNA structures. Surprisingly, selective use of the diffraction data in the 3.4, shell improves the overall success rate of the combined-mode classification. An open-source CCP4/CCP4i -compatible version of DIBER is available from the authors' website at and is subject to the GNU Public License. [source]