Silanation and stability of 3-aminopropyl triethoxy silane on nanosized superparamagnetic particles: I. Direct silanation

The direct silanation of nanosized superparamagnetic particles (γ-Fe₂O₃) using 3-aminopropyl triethoxy silane is described. The silanized films are characterized using X-ray photoelectron spectroscopy, diffuse-reflectance Fourier transform infrared spectroscopy and electrokinetics. The silanation is conducted in both organic (toluene) and water solutions to examine the solvent effect on the molecular orientation and packing density of the silanized films. Depending on the solvent, about 74 to 83% of amine groups are found to be un-protonated and remain reactive on the particles. In acidic environment, the films silanized in toluene are more stable than that in water, but both are unstable in basic environment.     

Synthesis and identification of two potential oxidation degradants of oxymetazoline

Two potential oxidation degradants of oxymetazoline have been isolated by liquid chromatography and monitored by electrospray single quadrupole mass spectrometry. The structures of the products are shown to be oxymetazoline N-oxide and hydroxyamine by multiple-stage fragmentation ion trap mass spectrometry. The product ion spectra were installed in a library database and the library was used to examine an aged commercial product; one of the degradants was detected, but at a level of less than 0.1% of the parent.     

Thermochemistry of polyhalides. II. Caesium and rubidium dibromoiodides

Using a solution-reaction calorimeter the standard enthalpies of formation of crystalline caesium and rubidium dibromoiodides have been determined as ?445.5±4.1 and ?428.3±4.2 kJ mol^?1, respectively. Thermodynamic parameters, including lattice energies, are calculated and the thermal stability of polyhalides discussed. Thermometric titrations have been used to investigate the mechanism of reaction of caesium dibromoiodide with aqueous silver nitrate.     

Glial Model for Traumatic Brain Injury: Network Strain Field and Inflammation Induced by Repeated Mechanical Impacts <Emphasis Type=Italic>In Vitro</Emphasis>

Traumatic brain injury (TBI) is a form of acquired brain trauma in which sudden external mechanical insults damage brain structures and cells. With a wide range of severities, TBI induces inflammatory responses with neurodegeneration and dysfunction. To develop new treatments, reproducible models of implementation are needed. Moreover, these models need to exhibit high biological and mechanical fidelity to the injurious event that they are trying to mimic. Here, the Highly Automated Mechanical Impactor (HAMr) is used to deliver 64 controlled pressure-pulses of known magnitude and duration to mixed glia cultures as a model for repetitive TBI. The mechanical response of those glial networks was quantified in terms of induced strain histories using Digital Image Correlation (DIC) under high-speed microscopic imaging. Four hours post-impact, glial network shearing and gene expression increases of TNFα and IL-1α were observed. However, select microglia and astrocyte markers were unchanged. These findings validate HAMr as a tool that enables quantification of the cell-substrate strain history during impact loading while reproducibly inducing inflammation and damaging glial network integrity, which are both common consequences of TBI.     

Classical probability and the quantum mechanical trace formulation for expectations

The trace formulation of quantum mechanical expectations is derived in a classical deterministic setting by averaging over an assembly of states. Interference of probabilities is discussed and its usual Hilbert space formulation is questioned. Nevertheless, it is shown that the observable predictions of quantum statics remain unchanged in the framework developed here.     

A useful UV spectroscopic method for the determination of the concentration of diethylenetriamine (DETA) in aqueous mineral flotation solutions

An alternative method for the determination of the concentration of diethylenetriamine (DETA) in aqueous mineral flotation solutions is described. This method is based on the formation of a DETA-Ni(II)-sulphite complex, which shows a UV absorption maximum at 285 nm that varies linearly with the concentration of DETA throughout the 0-50 mg l(-1) DETA range. A high concentration of Ni(II) is used to offset the effect of any Cu(II) or Ni(II) ions that may already be present in the industrial plant solutions under analysis. The intensity of the absorbance maximum is dependent on the sulphite ion concentration, but this problem is overcome by measuring the absorbances when the test solutions are spiked with different concentrations of DETA and then extrapolating the absorbance versus DETA concentration plot to zero absorbance to obtain the original concentration of DETA in the test solutions.     

Analytical performance is improved by regular participation in proficiency testing: an analysis of data from the Aquacheck proficiency testing scheme

Analysis of historical data from the Aquacheck proficiency testing scheme demonstrates improvement in the performance of participants correlated to the frequency of participation. Analysis of the spread of results returned by all participants, defined by the percentage relative standard deviation (RSD) and the performance (Z) scores awarded to the individual participants, indicates that the overall performance for the group of participants is consistent. However, when the frequency of participation is analysed, it can be clearly seen that those laboratories who participated in the majority of the distributions available reported 10–15% more acceptable (Z-scores between +2 and ?2) results than those labs who took part with a greatly reduced frequency. When ‘more difficult’ analytes are considered, those laboratories who participated in greater than 75% of available rounds reported up to 30% more acceptable results than those laboratories who participated in 25% or fewer, of the available rounds.