Gold nanoparticle growth on self-assembled monolayers of ferrocenyl-substituted terpyridine on graphite

In this contribution we demonstrate that densely packed gold nanoparticles can be grown by Volmer–Weber mode on ferrocenyl functionalized terpyridine (FcTerp) on graphite. FcTerp forms highly ordered and dense self-assembled monolayers (SAMs) on graphite which significantly reduces the diffusion length of gold atoms and increases the sticking coefficient compared to bare graphite. Both effects lead to an increased nucleation and thus, to the growth of densely packed gold nanoparticles with diameters in the nanometer range. The optical properties of the nanoparticles as well as their morphology and the structure of the SAMs were characterized by optical extinction spectroscopy and scanning tunneling microscopy.     

Risk-based classification system of nanomaterials

Various stakeholders are increasingly interested in the potential toxicity and other risks associated with nanomaterials throughout the different stages of a product’s life cycle (e.g., development, production, use, disposal). Risk assessment methods and tools developed and applied to chemical and biological materials may not be readily adaptable for nanomaterials because of the current uncertainty in identifying the relevant physico-chemical and biological properties that adequately describe the materials. Such uncertainty is further driven by the substantial variations in the properties of the original material due to variable manufacturing processes employed in nanomaterial production. To guide scientists and engineers in nanomaterial research and application as well as to promote the safe handling and use of these materials, we propose a decision support system for classifying nanomaterials into different risk categories. The classification system is based on a set of performance metrics that measure both the toxicity and physico-chemical characteristics of the original materials, as well as the expected environmental impacts through the product life cycle. Stochastic multicriteria acceptability analysis (SMAA-TRI), a formal decision analysis method, was used as the foundation for this task. This method allowed us to cluster various nanomaterials in different ecological risk categories based on our current knowledge of nanomaterial physico-chemical characteristics, variation in produced material, and best professional judgments. SMAA-TRI uses Monte Carlo simulations to explore all feasible values for weights, criteria measurements, and other model parameters to assess the robustness of nanomaterial grouping for risk management purposes.     

First measurements with the neutron decay spectrometer a SPECT

The neutron decay spectrometera SPECT has been built to perform a precise measurement of the proton spectrum shape in the decay of free neutrons. Such a measurement allows a determination of the neutrino electron angular-correlation coefficienta . The present best experiments have an uncertainty of Δa/a = 5% and since the seventies there is no substantial improvement. Witha SPECT, we aim for an uncertainty which is lower by more than an order of magnitude, thus enabling us to perform several precise tests of the Standard Model. In our first beam time at the particle physics beam MEPHISTO at the Forschungsneutronenquelle Heinz Maier-Leibnitz, we studied the properties of the spectrometer. The most serious problem turned out to be the situation- and time-dependent behavior of the background. From the data sets from this beam time in which a background problem was not obvious, we could extract a value ofa = - 0.1151±0.0040^stat , but we could not quantify the background uncertainty. We show ways to deal with the background and other problems for future beam times.     

Nuclear liquid-gas phase transition within the lattice gas model

We study the nuclear liquid-gas phase transition on the basis of a two-component lattice gas model. A Metropolis type of sampling method is used to generate microscopic states in the canonical ensemble. The effective equation of state and fragment mass distributions are evaluated in a wide range of temperatures and densities. A definition of the phase coexistence region appropriate for small systems is proposed. The caloric curve resulting from different types of freeze-out conditions are presented.     

Evidence for IFN-β heterogeneity in a substrain of namalwa cells

A substrain of Namalwa cells, denoted substrain B, was grown in fermentors up to the 100-L scale, and was induced with Sendai virus to produce interferon (IFN). The titer of the crude IFN varied extensively between different batches; part of the variation was caused by a differential expression of IFN-alpha and IFN-beta. More than 80% of the IFN activity was IFN-beta by several criteria. A two-step purification procedure was developed and the resulting preparation had a specific activity of approximately 10(6) U/mg protein. The IFN-beta type was found to be heterogeneous, and could be separated into several components, which probably represented post-translational modifications of one molecule.     

The first excited state in the doubly-closed-shell nucleus 132Sn populated in the 0.12 s β−-decay of 132In

A 0.12 ± 0.02 s beta activity assigned to the decay of ¹³²In and populating an excited state at 4041 ± 2 keV in the doubly-closed-shell nucleus ₅₀¹³²Sn₈₂ has been observed. This state is tentatively assigned to arise from the 3^? octupole vibration.     

Isotope ratio determination in microgram levels of osmium by deuteron activation analysis

We have demonstrated the feasibility of determining isotope ratios in very small samples of osmium by deuteron activation in the Livermore Tandem Van de Graaff accelerator. The method involves determination of cross-section ratios by using several osmium isotope mixtures carefully prepared from electromagnetically-enriched osmium isotopes. The accuracy of this method was checked by a determination of the isotope ratios in naturally-occurring osmium. Our analysis demonstrated that an osmium specimen removed from a sample of commercial grade perrhenic acid contained only 0.4% natural osmium, the rest being radiogenic¹⁸⁷Os.Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.     

Fluorometric determination of non-fluorescent amines by ion-pair extraction

Summary An ion pair extraction method is described for quantitative fluorometric determination in the ng/ml range of non-fluorescent amines used as drugs. As counter ion, reagent, anthracene-2-sulphonate was used. Its extracting ability of ion pairs with amines was studied by determination of extraction constants and its fluorescence properties by determination of quantum yield of fluorescence. The properties of a suitable organic solvent is discussed and methylene chloride was found to be advantageous. Conditions for quantitative extraction and determination are given and the method was applied to determination of amitriptyline in the range 10–100 ng/ml giving an extraction degree of 100% and a precision of 5%.

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Fluorimetrische Bestimmung nicht fluorescierender Amine durch Ionenpaarextraktion

Zusammenfassung Die untersuchten Amine finden Verwendung als Arzneimittel und können in Mengen von ng/ml bestimmt werden. Anthracen-2-sulfonat dient als Gegenion. Die Eignung zur Ionenpaarextraktion wird durch Bestimmung der Extraktionskonstanten geprüft. Die Fluorescenzeigenschaften werden durch Messung der Quantenausbeuten der Fluorescenz bestimmt. Die erforderlichen Eigenschaften eines Lösungsmittels werden diskutiert. Methylenchlorid erweist sich dabei als gut geeignet. Die Bedingungen für quantitative Extraktion und Bestimmung werden angegeben. Die Methode wurde für die Bestimmung von Amitriptyline im Bereich 10–100 ng/ml ausgearbeitet, wobei sich ein Extraktionsgrad von 100% und eine Präzision von 5% ergaben.

     

Fragmentation in neutrino and antineutrino charged current interactions on proton and neutron

Some experimental properties of the charged hadronic fragments are compared for νp, νn, \(\bar vp\) and \(\bar vn\) interactions: multiplicities of forward and backward going particles,x _F distributions for pions, fragmentation functions and theirQ ² andW ² dependence. The results are compared with the predictions of the Lund fragmentation model.