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We employed a recently introduced class of sterol-modified lipids (SML) to produce m-PEG-DSPE containing liposome compositions with a range of cis-platinum content release rates. SML have a cholesterol succinate attached to the phosphatidylglycerol head group and a fatty acid at the 2 position. These compositions were compared to the well-studied liposome phospholipid compositions: mPEG-DSPE/Hydrogenated Soy PC/cholesterol or mPEG-DSPE/POPC/cholesterol to determine the effect of the cis-platinum release extent on C26 tumor proliferation in the BALB/c colon carcinoma mouse model. The release rates of cis-platinum from liposomes composed of SML are a function of the acyl chain length. SML-liposomes with shorter acyl chain lengths C-8 provided more rapid cisplatin release, lower in vitro IC50, and were easier to formulate compared to liposomes using traditional phospholipid compositions. Similar to other liposome cis-platinum formulations, the half-life of m-PEG-DSPE SML liposome cisplatin is substantially longer than the free drug. This resulted in a higher tumor cisplatin concentration at 48h post-dosing compared to the free drug and higher Pt-DNA adducts in the tumor. Moreover, the maximum tolerated dose of the liposome formulations where up to four fold greater than the free drug. Using X-ray fluorescence spectroscopy on tumor sections, we compared the location of platinum, to the location of a fluorescence lipid incorporated in the liposomes. The liposome platinum co-localized with the fluorescent lipid and both were non-uniformly distributed in the tumor. Non-encapsulated Cis-platinum, albeit at a low concentration, was more uniformly distributed thorough the tumor. Three liposome formulations, including the well-studied hydrogenated HSPC composition, had better antitumor activity in the murine colon 26 carcinoma model as compared to the free drug at the same dose but the SML liposome platinum formulations did not perform better than the HSPC formulation.

The goal of this study was to demonstrate how synchrotron-based X-ray fluorescence microscopy (XFM) can be used to better understand the mechanisms of copper tolerance in wood decay fungi. Copper is a major component in commercial wood preservatives as it is toxic to many wood decay fungi. However, certain fungi are copper tolerant and can attack preservative-treated wood, resulting in structural damage to treated wood members. Here we used large-field XFM to visualize six different elements (K, Ca, Mn, Fe, Cu, and Zn) in the mycelia and wood inoculated with four different species of brown rot wood decay fungi. Wood blocks were partially dipped into a solution of copper sulfate, exposed to fungi in malt extract agar petri dish assays for nine weeks, and then imaged and compared to blocks that were partially dipped in water. The blocks were imaged immediately adjacent to an end-matched control that was placed in malt extract agar petri dish assays for 9 weeks, but not exposed to the fungi so that the differences in the elemental distributions could be directly compared. The colonized wood and mycelia were rich in K, Ca, Mn, and Fe; however, the elements and the spatial distribution in the mycelia and wood differed across fungal species. The most interesting results were the maps showing the copper distribution. While three of the four fungi grew on the copper-rich region of the wood, only one species, Fibroporia radiculosa, dramatically reduced the copper concentration in the region of fungal growth. [ABSTRACT FROM AUTHOR]

Lead (Pb) exposure is known to be associated with adverse effects on human health, especially during the prenatal period and early childhood. The Pb content in teeth has been suggested as a useful biomarker for the evaluation of cumulative Pb exposure. This study was designed to employ the microbeam synchrotron radiation X-ray fluorescence technique to determine the microdistribution of Pb within the tooth to evaluate the reliability of the technique and the effectiveness of tooth Pb as a biomarker of Pb exposure. The results showed that in the incisor sample, Pb primarily deposited in secondary dentine region close to the pulp and secondarily at enamel exterior. In addition, Pb colocalised with Zn, indicating a positive correlation between Pb and Zn. By contrast, in the two molar samples, Pb accumulated principally in the pulp, and secondarily in the enamel. At the same time, Pb in these two molar samples colocalised with Ca instead of Zn as was observed in the incisor sample. Several batches of line scans further confirmed the conclusions. The feasibility of using microbeam synchrotron radiation X-ray fluorescence to determine the microdistribution of Pb in teeth and of using the tooth Pb, especially in dentine, as a biomarker was discussed. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A dense tubular solid electrolyte with the composition Ce0.8Y0.2O1.9−δ (CY20) was prepared. In situ time-of-flight neutron powder diffraction (TOF-ND) was performed at 900°C in the oxygen partial pressure pO2 range from 10−1–10−18 atm, and TOF-ND data were analyzed by the Rietveld method. Diffraction data showed that the lattice parameter moderately increased with decreasing pO2 in the range of pO2>10−14 atm, while a dramatic expansion (∼0.6%) of the fluorite structure occurred at a pO2 of 10−18 atm. By refining all reasonable structural parameters, an approximately linear relationship between lattice parameter and oxygen vacancy δ was observed, resulting in ℇc/δ=0.08 and corresponding to δ=0.10 at a pO2 of 10−18 atm, all in agreement with the data published in the literature. The relative change in lattice parameter Δ a/ a followed a −1/4 power relation with pO2 in a low- pO2 regime. As several (often strongly correlated) structural parameters can affect the intensities in ND profiles, care was taken to select refinement variables. It was found that O atom thermal factors for CY20 increased as the oxygen vacancy concentration and lattice expansion increased. [ABSTRACT FROM AUTHOR]

The oxygen partial pressure (pO2)-dependent structural behaviors of two dense tubular ceramic membranes in composition SrFe0.2Co0.8O x with cubic perovskite structure have been investigated by high-temperature neutron powder diffraction: one in“static” mode and one in simulated-operation mode in which one side of the membrane was exposed to air and the other side to reducing gases with variablepO2 levels. Rietveld analysis on data collected for the membrane withoutpO2 gradients showed that the perovskite is stable inpO2 down to∼10−12 atm, and at∼10−14 atm it starts to decompose into a three-phase mixture containing layered intergrowth Ruddlesden–Popper phases Sr n+1(Fe,Co) nO x withn=2 and 3, along with CoO with rocksalt structure. Similar phase evolution was observed when insufficient air flowed on the air side of the membrane exposed to apO2 gradient. The data support a nonlinear model of oxygen content in perovskite across the membrane thickness, corresponding to apO2 profile that is shallow inside and steep near the reducing side surface. Gas compositions measured with mass spectrometry indicated that oxygen is permeated from the air side to the reducing side of the membrane. The oxygen permeation fluxes at 900°C were estimated to be 0.4–0.9 sccm/cm2 for the∼1 mm thick membrane containing perovskite, depending uponpO2 gradient. [ABSTRACT FROM AUTHOR]

Abstract: The search for alternative fuel has spurred interest in complexes with high hydrogen absorption–desorption capacities. Among these compounds complex metal hydrides have received much attention. More recently, it was proposed that simple metal nitrides such as lithium nitride (Li3N), with its 9wt% recyclable hydrogen uptake, could be good candidates for reversible hydrogen storage. In this paper, we present the results of detailed structural study of Li3N through the temperature range 20–673K using neutron powder diffraction. Commercially purchased compound showed a co-existence of alpha and beta phases of Li3N. We observed a steady decline of the beta phase above 473K and a very small fraction (∼2.5wt%) remained untransformed at 673K. This transformation (beta to alpha) was not reversible on cooling. [Copyright &y& Elsevier]

Archeological ceramic paste material typically consists of a mix of a clay matrix and various millimeter and sub-millimeter sized mineral inclusions. Micro X-ray fluorescence (XRF) is a standard compositional classification tool and in this work we propose and demonstrate an improved fluorescence map processing protocol where the mineral inclusions are automatically separated from the clay matrix to allow independent statistical analysis of the two parts. Application of this protocol allowed us to enhance the discrimination between different ceramic shards compared with the standard procedure of working with only the spatially averaged elemental concentrations. Using the new protocol, we performed an initial compositional classification of a set of 83 ceramic shards from the western slopes of the south central Andean region in the Arica y Parinacota region (Chile). Comparing the classifications obtained using the new versus the old (average concentrations only) protocols, we found that some samples were erroneously classified with the old protocol. From an archaeological perspective, a broad and heterogeneous regional sample set was used in this experimental study due to the fact that this was the first such analysis to be performed on ceramics from this region. This allowed a general overview to be obtained, however further work on more specific sample sets will be necessary to extract concrete archaeological conclusions. [ABSTRACT FROM AUTHOR]

Abstract: Neutron and synchrotron studies have been performed on in situ hydriding of Li3N. Commercial Li3N is composed of α phase (∼70wt.%) and β phase (∼30wt.%). We have performed experiments to convert β→α, and studied in situ deuteration using neutron diffraction experiments. We found concurrent phase evolution of Li2ND, LiD, and LiND2. Mass percentages of the phases evolved as a function of time and temperature have been quantified using General Structure Analysis System (GSAS) refinement of the neutron diffraction data. The problem of formation of the stable LiD is discussed in light of decreasing of the amount of LiD phase when the temperature is increased from 200 to 320°C during dehydriding, and in addition the concentration of Li2ND phase increased at this temperature. Lattice parameters, volume changes, phase evolutions in wt.% as a function of temperature and time are presented. [Copyright &y& Elsevier]