Screening for organic phosphorus compounds in aquatic sediments by liquid chromatography coupled to ICP-AES and ESI-MS/MS

The structures of organic phosphorous (P) compounds in aquatic sediments are to a large extent unknown although these compounds are considered to play an important role in regulating lake trophic status. To enhance identification of these compounds, a liquid chromatography (LC) method for their separation was developed. The stationary phase was porous graphitic carbon (PGC), and the mobile phases used in the gradient elution were compatible with both inductive coupled plasma atomic emission spectroscopy (ICP-AES) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). With LC-ICP-AES, eight different P containing peaks could be observed in the P chromatogram indicating that at least eight different P compounds were separated. With the setup of an information dependent acquisition (IDA) with ESI-MS/MS, the mass over charge ( m/ z) of compounds containing a phosphate group (H 2PO 3 (-), m/ z 97) could be measured and further fragmentation experiments gave additional information on the structure of almost 40 separated P compounds, several were verified to be nucleotides. ICP-AES was very suitable in the development of the LC method and allowed screening and quantification of P compounds. The presented LC-ESI-MS/MS technique was able to identify several sediment organic P compounds.     

Detector Development for the Next Phases of the Cryogenic Dark Matter Search: Results from 1 Inch Ge and Si Detectors

The Cryogenic Dark Matter Search (CDMS) experiment is searching for Weakly Interacting Massive Particles (WIMPs) using detectors with the ability to discriminate between candidate (nuclear recoil) and background (electron recoil) events by measuring both phonon and ionization signals from recoils in the detector crystals. As CDMS scales up to greater WIMP sensitivity, it is necessary to increase the detector mass and further improve background discrimination. CDMS is engaged in ongoing fabrication and development of new detector designs in order to meet these criteria for the proposed SuperCDMS experiment. Thicker detector prototypes have been produced with new photolithographic masks. These masks have greater surface coverage of the quasi particle trap and transition edge sensor system to provide superior athermal phonon collection. Results from continuing laboratory tests are presented which already indicate improvement in discrimination parameters.      

Investigation of iodine bioavailability from chicken eggs versus iodized kitchen salt with in vitro method

The goal of the presented studies was to investigate speciation and bioavailability of iodine from chicken eggs versus iodized kitchen salt with an in vitro method. Determination of iodine total content in chicken eggs and iodized kitchen salt was carried out by inductively coupled plasma mass spectrometry (ICP MS). The majority of iodine was accumulated in the yolk—the concentration was even 37 times higher than in white. Chicken eggs were treated with buffer (Tris HCl pH = 7.5) and enzymatic extraction media and analyzed by size exclusion chromatography hyphenated with inductively coupled plasma mass spectrometry (SEC ICP MS). The enzymatic extraction being an in vitro bioavailability assessment method was based on two-stage digestion model simulating gastric (pepsin digestion) and intestinal (pancreatin digestion) juices. Speciation analyses along with bioavailability studies presented iodide as the major form in chicken eggs. The bioavailability was established as 33% from white and 10% from yolk and decreased with longer time of boiling. It allows to suggest that the majority of iodine remains in forms bound to non-digestible coagulated and water-insoluble proteins.     

Glycation compounds in peanuts

In the present study, the extent of the Maillard reaction in peanuts was investigated, using N-ε-fructosyllysine (ε-Fru-Lys, determined via furosine) as an indicator for the early stage, and pyrraline and N-ε-carboxymethyllysine (CML) as representatives for advanced glycation. In commercial samples, ε-Fru-Lys ranged between 1.5 and 13.3 mmol/mol lysine. Pyrraline was found in amounts between not detectable (below 0.3 mmol/mol lysine) and 9.0 mmol/mol lysine, and CML between 0.8 and 2.7 mmol/mol lysine. Lysine modification by glycation products was very low in cooked and fried peanuts (below 1%). In laboratory-scale roasting experiments, the amount of ε-Fru-Lys reached maximum values of 12.0 mmol/mol lysine after 20 min at 160 °C, whereas pyrraline increased up to 38.5 mmol/mol lysine after 25 min at 170 °C. Amount of CML was up to 1.8 mmol/mol lysine in peanuts roasted for 25 min at 170 °C. Such high amounts of pyrraline have not yet been described for any other food item. Only about one tenth of the totally observed lysine modification of up to 50% can be explained by the three glycation compounds, indicating that currently unknown reactions occur during peanut roasting. Reactions between proteins and carbonyl compounds, most likely originating from oxidative degradation of lipids, may play an important role for lysine derivatization in peanuts and should be analyzed more in detail.     

SiGe epitaxy on a 300 mm batch furnace

This work reports the feasibility of silicon and silicon germanium epitaxy using an ASM A412(TMa) LPCVD all quartz, hot wall, vertical batch furnace reactor using 100 wafer product loads. The very same furnace can be used for 25 wafer and 200 wafer load size, without any hardware changes, dependant on production needs. Following this approach a significant cost reduction for epitaxy in 300 mm high volume manufacturing is possible and enables new applications. The native oxide of the substrate was removed by wet chemical cleaning with time coupling of less than 1 h and subsequent in-situ low pressure hydrogen anneal prior to Si or SiGe deposition. The epitaxial layers were grown using silane and germane. The Si and SiGe layers have been characterized with ToFSIMS, XRD, Raman, AFM and TEM confirming excellent crystalline quality, layer thickness and within wafer SiGe stoichiometry uniformity.     

Controlled synthesis of uniform cobalt phosphide hyperbranched nanocrystals using tri-n-octylphosphine oxide as a phosphorus source

A new method to produce hyperbranched Co(2)P nanocrystals that are uniform in size, shape, and symmetry was developed. In this reaction tri-n-octylphosphine oxide (TOPO) was used as both a solvent and a phosphorus source. The reaction exhibits a novel monomer-saturation-dependent tunability between Co metal nanoparticle (NP) and Co(2)P NP products. The morphology of Co(2)P can be controlled from sheaflike structures to hexagonal symmetric structures by varying the concentration of the surfactant. This unique product differs significantly from other reported hyperbranched nanocrystals in that the highly anisotropic shapes can be stabilized as the majority shape (>84%). This is the first known use of TOPO as a reagent as well as a coordinating background solvent in NP synthesis.     

Infectivity of Trichinella nativa in traditional northern (country) foods prepared with meat from experimentally infected seals

The infectivity of Trichinella nativa larvae in three traditional northern (country) foods was assessed. Foods were prepared with meat from seals experimentally infected with Trichinella nativa and evaluated over a 317-day period during which this food was fed directly to cats while mice were orally inoculated with larvae recovered following the digestion of the food in a solution containing 1% pepsin and 1% HCl at 37 degrees C. Foods examined were igunaq (meat and blubber placed in a seal skin bag and allowed to ferment), nikku (air-dried meat), and sausage (meat, fillers, salt, and spices). Sausage was examined both in a raw state and after partial cooking. Infective T. nativa larvae survived in igunaq, nikku, raw frozen sausage, and poorly cooked sausage for at least 5 months under controlled laboratory conditions. Core temperatures of partially cooked sausage never exceeded 50 degrees C. Caution should be exercised in using these data to establish guidelines for the consumption of raw products, since the survival of infective larvae could be unpredictably extended under field conditions. These data indicate significant food safety risks associated with igunaq, nikku, and sausage prepared with Trichinella-infected meat and provide information for use in risk management and in directing future research.     

Gold and Cobalt Oxide Nanoparticles Modified Poly-Propylene Poly-Ethylene Glycol Membranes in Poly (ε-Caprolactone) Conduits Enhance Nerve Regeneration in the Sciatic Nerve of Healthy Rats

Reconstruction of nerve defects is a clinical challenge. Autologous nerve grafts as the gold standard treatment may result in an incomplete restoration of extremity function. Biosynthetic nerve conduits are studied widely, but still have limitations. Here, we reconstructed a 10 mm sciatic nerve defect in healthy rats and analyzed nerve regeneration in poly (ε-caprolactone) (PCL) conduits longitudinally divided by gold (Au) and gold-cobalt oxide (AuCoO) nanoparticles embedded in poly-propylene poly-ethylene glycol (PPEG) membranes (AuPPEG or AuCoOPPEG) and compared it with unmodified PPEG-membrane and hollow PCL conduits. After 21 days, we detected significantly better axonal outgrowth, together with higher numbers of activated Schwann cells (ATF3-labelled) and higher HSP27 expression, in reconstructed sciatic nerve and in corresponding dorsal root ganglia (DRG) in the AuPPEG and AuCoOPPEG groups; whereas the number of apoptotic Schwann cells (cleaved caspase 3-labelled) was significantly lower. Furthermore, numbers of activated and apoptotic Schwann cells in the regenerative matrix correlated with axonal outgrowth, whereas HSP27 expression in the regenerative matrix and in DRGs did not show any correlation with axonal outgrowth. We conclude that gold and cobalt-oxide nanoparticle modified membranes in conduits improve axonal outgrowth and increase the regenerative performance of conduits after nerve reconstruction.     

Synthesis of alkali-metal-doped C60 nanotubes

C₆₀ nanotubes have been synthesized by a solution-solution method. After degassing in a dynamic vacuum, the C₆₀ nanotubes doped with alkali metals by means of vapor evaporation method. Different temperatures have been studied to evaporate the alkali metals for the doping experiments. Raman spectrum was further employed to analyze the doping concentration of the obtained samples. It was found that all three alkali metals (Li, Na and K) used can be efficiently doped into the C₆₀ nanotubes, forming A_xC₆₀ nanotubes. The doping concentration of Li, Na changed from low to high level, depending on the experiment temperatures, while K doping always gave saturated doping. The melt points, the ionic sizes and vapor pressures of alkali metals were thought to affect the final doping results.