Metastable BrO(2+) and NBr(2+) molecules in the gas phase

The doubly positively charged gas-phase molecules BrO(2+) and NBr(2+) have been produced by prolonged high-current energetic oxygen (17 keV (16)O(-)) ion surface bombardment (ion beam sputtering) of rubidium bromide (RbBr) and of ammonium bromide (NH(4)Br) powdered ionic salt samples, respectively, pressed into indium foil. These novel species were observed at half-integer m/z values in positive ion mass spectra for ion flight times of roughly similar to 12 mu s through a magnetic-sector secondary ion mass spectrometer. Here we present these experimental results and combine them with a detailed theoretical investigation using high level ab initio calculations of the ground states of BrO(2+) and NBr(2+), and a manifold of excited electronic states. NBr(2+) and BrO(2+), in their ground states, are long-lived metastable gas-phase molecules with well depths of 2.73 x 10(4) cm(-1) (3.38 eV) and 1.62 x 10(4) cm(-1) (2.01 eV); their fragmentation channels into two monocations lie 2.31 x 10(3) cm(-1) (0.29 eV) and 2.14 x 10(4) cm(-1) (2.65 eV) below the ground state minimum. The calculated lifetimes for NBr(2+) (v '' < 35) and BrO(2+) (v '' < 18) are large enough to be considered stable against tunneling. For NBr(2+), we predicted R(e) = 3.051 a(0) and omega(e) = 984 cm(-1); for BrO(2+), we obtained 3.033 a(0) and 916 cm(-1), respectively. The adiabatic double ionization energies of BrO and NBr to form metastable BrO(2+) and NBr(2+) are calculated to be 30.73 and 29.08 eV, respectively. The effect of spin-orbit interactions on the low-lying (Lambda + S) states is also discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3562121]

Exploitation of a single interface flow system for on-line aqueous biphasic extraction

The exploitation of aqueous biphasic extraction is proposed for the first time in flow analysis This extraction strategy stands out for being environmentally attractive since it is based in the utilization of two immiscible phases that are intrinsically aqueous The organic solvents of the traditional liquid-liquid extractions ale no longer used, being replaced by non-toxic, non-flammable and non-volatile ones. A single interface flow analysis (SIFA) system was implemented to carry out the extraction process due to its favourable operational characteristics that include the high automation level and simplicity of operation, the establishment of a dynamic interface where the mass transfer occurred between the two immiscible aqueous phases, and the versatile control over the extraction process namely the extraction time The application selected to demonstrate the feasibility of SIFA to perform this aqueous biphasic extraction was the pre-concentration of lead. After extraction, lead reacted with 8-hydroxyquinoline-5-sulfonic acid and the resulting product was determined by a fluorimetric detector included in the flow manifold. Therefore, the SIFA single interface was used both as extraction (enrichment) and reaction interface. (C) 2010 Elsevier B.V All rights reserved.

Multi-commutation in spectrometry

We review recent developments in manifold components and the introduction of light-emitting-diode technology in spectroscopic detection in order to evaluate the tremendous possibilities offered by multi-commutation for infield and in-situ measurements, based on the use of multi-pumping and low-voltage, portable batteries, which make possible a dramatic reduction in size, weight and power requirements of spectrometric devices. (C) 2009 Elsevier Ltd. All rights reserved.

Total and inorganic mercury determination in fish tissue by flow injection cold vapour atomic fluorescence spectrometry

A simple and reliable method for Hg determination in fish samples has been developed. Lyophilised fish tissue samples were extracted in a 25% (w/v) tetramethylammonium hydroxide (TMAH) solution; the extracts were then analysed by FI-CVAFS. This method can be used to determine total and inorganic Hg, using the same FI manifold. For total Hg determination, a 0.1% (w/v) KMnO(4) solution was added to the FI manifold at the sample zone, followed by the addition of a 0.5% (w/v) SnCl(2) solution, whereas inorganic Hg was determined by adding a 0.1% (w/v) L-cysteine solution followed by a 1.0% (w/v) SnCl(2) solution to the FI system. The organic fraction was determined as the difference between total and inorganic Hg. Sample preparation, reagent consumption and parameters that can influence the FI-CVAFS performance were also evaluated. The limit of detection for this method is 3.7 ng g(-1) for total Hg and 4.3 ng g(-1) for inorganic Hg. The relative standard deviation for a 1.0 mu gL(-1) CH(3)Hg standard solution (n = 20) was 1.1%, and 1.3% for a 1.0 mu gL(-1) Hg(2+) standard solution (n = 20). Accuracy was assessed by the analysis of Certified Reference Material (dogfish: DORM-2, NRCC). Recoveries of 99.1% for total Hg and 93.9% inorganic Hg were obtained. Mercury losses were not observed when sample solutions were re-analysed after a seven day period of storage at 4 degrees C.

An expert flow system involving in-line prior assay for turbidimetric determination of chloride and sulphate in natural waters

A multi-pumping flow system exploiting prior assay is proposed for sequential turbidimetric determination of sulphate and chloride in natural waters. Both methods are implemented in the same manifold that provides facilities for: in-line sample clean-up with a Bio-Rex 70 mini-column with fluidized beads: addition of low amounts of sulphate or chloride ions to the reaction medium for improving supersaturation; analyte precipitation with Ba(2+) or Ag(+); real-time decision on the need for next assay. The sample is initially run for chloride determination, and the analytical signal is compared with a preset value. If higher, the sample is run again, now for sulphate determination. The strategy may lead to all increased sample throughput. The proposed system is computer-controlled and presents enhanced figures of merit. About 10 samples are run per hour (about 60 measurements) and results are reproducible and Unaffected by the presence of potential interfering ions at concentration levels usually found in natural waters. Accuracy was assessed against ion chromatography. (C) 2008 Elsevier B.V. All rights reserved.

Non-linear modal analysis for beams subjected to axial loads: Analytical and finite-element solutions

A rigorous derivation of non-linear equations governing the dynamics of an axially loaded beam is given with a clear focus to develop robust low-dimensional models. Two important loading scenarios were considered, where a structure is subjected to a uniformly distributed axial and a thrust force. These loads are to mimic the main forces acting on an offshore riser, for which an analytical methodology has been developed and applied. In particular, non-linear normal modes (NNMs) and non-linear multi-modes (NMMs) have been constructed by using the method of multiple scales. This is to effectively analyse the transversal vibration responses by monitoring the modal responses and mode interactions. The developed analytical models have been crosschecked against the results from FEM simulation. The FEM model having 26 elements and 77 degrees-of-freedom gave similar results as the low-dimensional (one degree-of-freedom) non-linear oscillator, which was developed by constructing a so-called invariant manifold. The comparisons of the dynamical responses were made in terms of time histories, phase portraits and mode shapes. (C) 2008 Elsevier Ltd. All rights reserved.

Heat flow for Yang-Mills-Higgs fields, part I

The Yang-Mills-Higgs field generalizes the Yang-Mills field. The authors establish the local existence and uniqueness of the weak solution to the heat flow for the Yang-Mills-Higgs field in a vector bundle over a compact Riemannian 4-manifold, and show that the weak solution is gauge-equivalent to a smooth solution and there are at most finite singularities at the maximum existing time.

Heat flow for the Yang-Mills-Higgs field and the Hermitian Yang-Mills-Higgs metric

For a parameter lambda > 0, we study a type of vortex equations, which generalize the well-known Hermitian-Einstein equation, for a connection A and a section phi of a holomorphic vector bundle E over a Kahler manifold X. We establish a global existence of smooth solutions to heat flow for a self-dual Yang-Mills-Higgs field on E. Assuming the lambda -stability of (E, phi), we prove the existence of the Hermitian Yang-Mills-Higgs metric on the holomorphic bundle E by studying the limiting behaviour of the gauge flow.

Bayesian analysis of the error correction model

This paper presents a method for estimating the posterior probability density of the cointegrating rank of a multivariate error correction model. A second contribution is the careful elicitation of the prior for the cointegrating vectors derived from a prior on the cointegrating space. This prior obtains naturally from treating the cointegrating space as the parameter of interest in inference and overcomes problems previously encountered in Bayesian cointegration analysis. Using this new prior and Laplace approximation, an estimator for the posterior probability of the rank is given. The approach performs well compared with information criteria in Monte Carlo experiments. (C) 2003 Elsevier B.V. All rights reserved.

A multi-purpose rainfall simulator for field infiltration and erosion studies

This paper describes a rainfall simulator developed for field and laboratory studies that gives great flexibility in plot size covered, that is highly portable and able to be used on steep slopes, and that is economical in its water use. The simulator uses Veejet 80100 nozzles mounted on a manifold, with the nozzles controlled to sweep to and from across a plot width of 1.5 m. Effective rainfall intensity is controlled by the frequency with which the nozzles sweep. Spatial uniformity of rainfall on the plots is high, with coefficients of variation (CV) on the body of the plot being 8-10%. Use of the simulator for erosion and infiltration measurements is discussed.

Mortality problems in Brazil and in Germany: past-present-future. Learning from each other?

This article was written by a Swiss-German historical demographer after having visited different Brazilian Universities in 1984 as a guest-professor. It aims at promoting a real dialog between developed and developing countries, commencing the discussion with the question: Can we learn from each other? An affirmative answer is given, but not in the superficial manner in which the discussion partners simply want to give each other some "good advice" or in which the one declares his country's own development to be the solely valid standard. Three points are emphasized: 1. Using infant mortality in S. Paulo from 1908 to 1983 as an example, it is shown that Brazil has at its disposal excellent, highly varied research literature that is unjustifiably unknown to us (in Europe) for the most part. Brazil by no means needs our tutoring lessons as regards the causal relationships; rather, we could learn two things from Brazil about this. For one, it becomes clear that our almost exclusively medical-biological view is inappropriate for passing a judgment on the present-day problems in Brazil and that any conclusions so derived are thus only transferable to a limited extent. For another, we need to reinterpret the history of infant mortality in our own countries up to the past few decades in a much more encompassing "Brazilian" sense. 2. A fruitful dialog can only take place if both partners frankly present their problems. For this reason, the article refers with much emprasis to our present problems in dealing with death and dying - problems arising near the end of the demographic and epidemiologic transitions: the superanuation of the population, chronic-incurable illnesses as the main causes of death, the manifold dependencies of more and more elderly and really old people at the end of a long life. Brazil seems to be catching up to us in this and will be confronted with these problems sooner or later. A far-sighted discussion already at this time seems thus to be useful. 3. The article, however, does not want to conclude with the rather depressing state of affairs of problems alternatingly superseding each other. Despite the caution which definitely has a place when prognoses are being made on the basis of extrapolations from historical findings, the foreseeable development especially of the epidemiologic transition in the direction of a rectangular survival curve does nevertheless provide good reason for being rather optimistic towards the future: first in regards to the development in our own countries, but then - assuming that the present similar tendencies of development are stuck to - also in regard to Brazil.

XRCC3 THR241MET polymorphism influence on nuclear buds frequency in exposed to formaldehyde

Formaldehyde (FA), also known as formalin, formal and methyl aldehydes, is a colorless, flammable, strong-smelling gas. It has an important application in embalming tissues and that result in exposures for workers in the pathology anatomy laboratories and mortuaries. Occupational exposure to FA has been shown to induce nasopharyngeal cancer and has been classified as carcinogenic to humans (group 1) on the basis of sufficient evidence in humans and sufficient evidence in experimental animals. Manifold in vitro studies clearly indicated that FA is genotoxic. FA induced various genotoxic effects in proliferating cultured mammalian cells. The cytokinesis-block micronucleus (CBMN) assay was originally developped as an ideal system form easuring micronucleus (MN), however it can also be used to measure nucleoplasmic bridges (NBP) and nuclear buds (NBUD). Over the past decade another unique mechanism of micronucleus formation, known as nuclear budding has emerged. NBUDS is considered as a marker of gene amplification and/or altered gene dosage because the nuclear budding process is the mechanism by which cells removed amplified and/excess DNA.

Genotoxicity biomarkers in occupational to formaldehyde in pathology anatomy laboratories

Formaldehyde (FA) the most simple and reactive of all aldehydes, is a colorless, reactive and readily polymerizing gas at normal temperature. It has a pungent, suffocating odour that is recognized by most human subjects at concentrations below 1ppm. According to the Report on Carcinogens, FA ranks 25th in the overall U.S. chemical production with more than 11 billion pounds (5 million tons) produced each year. Is an important industrial compound that is used in the manufacture of synthetic resins and chemical compounds such as lubricants and adhesives. It has also applications as a disinfectant, preservative and is used in cosmetics. Estimates of the number of persons who are occupationally exposed to FA indicate that, at least at low levels, may occur in a wide variety of industries. The occupational settings with most extensive use of formaldehyde is in the production of resins and in anatomy and pathology laboratories. Several studies reported a carcinogenic effect in humans after inhalation of FA, in particular an increased risk for nasopharyngeal cancer. Nowadays, the International Agency for Research on Cancer (IARC) classifies FA as carcinogenic to humans (group 1), on the basis of sufficient evidence in humans and sufficient evidence in experimental animals. Manifold in vitro studies clearly indicated that FA is genotoxic. FA induced various genotoxic effects in proliferatin cultured mammalian cells. A variety of evidence suggests that the primary DNA alterations after FA exposure are DNA-protein crosslinks. Incomplete repair of DPX can lead to the formation of mutations.

Formaldehyde's genotoxicity effects in pathology anatomy technologists and medical pathologists

Formaldehyde (FA) had been considered to be carcinogenic by the International Agency for Research on Cancer (group1), on the basis of sufficient evidence both in humans and in experimental animals, making it a subject of major environmental concern, especially in the occupational context. Manifold in vitro studies clearly indicated that FA is genotoxic, inducing various genotoxic effects in proliferating cultured mammalian cells. Cytokinesis-blocked micronucleus (CBMN) assay is used extensively in molecular epidemiology, and the chromosomal alterations most reported and studied by the CBMN are: micronucleus (MN), nucleoplasmic bridges (NPB) and nuclear buds (NBUDs). The pathology anatomy laboratories are work places that manipulate routinely FA and pathology anatomy technologists and pathologists contact daily with this chemical compound particularly in the macroscopic exam and grossing procedures. The aim of this study was to identify genotoxicity biomarkers in the set workers groups, such as micronucleus (MN), nucleoplasmic bridges (NPB) and nuclear buds (NBUD) in peripheral blood lymphocytes.

Occupational exposure to formaldehyde: effects of years of exposure in the frequency of micronucleus

Formaldehyde: an important industrial compound used in the manufacture of synthetic resins and chemical compounds such as lubricants and adhesives; also applied as a disinfectant, preservative and in cosmetics productions; relevant workplace exposure to FA also occurs in anatomy, pathology and in mortuaries; classified by IARC as carcinogenic to humans (Group 1), based on sufficient evidence in humans and experimental animals; manifold in vitro studies indicated that FA can induce genotoxic effects in proliferating cultured mammalian cells. Aim of the study: to evaluate if years of exposure induced a genotoxic biomarkers increase, namely MN in lymphocytes and buccal cells, in workers occupationally exposed to FA (factory and pathology anatomy laboratory).