A three‐dimensional hydrogen‐bonded framework in (2S*,4R*)‐7‐fluoro‐2‐exo‐[(E)‐styryl]‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine

Molecules of the title compound, C₁₈H₁₆FNO, are linked into a three‐dimensional framework structure by a combination of two C—H...O hydrogen bonds and three C—H...π(arene) hydrogen bonds. Comparisons are made with the (2R,4R) diastereoisomer and with the corresponding pair of diastereoisomeric 7‐chloro analogues.     

Bioavailability of nanoparticles in nutrient and nutraceutical delivery

The field of nanoparticle delivery systems for nutrients and nutraceuticals with poor water solubility has been expanding, almost exponentially, over the last five years, and some of these technologies are now in the process of being incorporated in food products. The market projections for these technologies suggest a multifold increase in their commercial potential over the next five years. The interest in the pharmaceutical and food-related applications of these technologies has sparked tremendous developments in mechanical (top-down) and chemical (bottom-up) processes to obtain such nanoparticle systems. Mechanical approaches are capable of producing nanoparticles, typically in the 100–1000 nm range, whereas chemical methods tend to produce 10–100 nm particles. Despite these technological developments, there is a lack of information regarding the basis of design for such nanoparticle systems. Fundamental thermodynamic and mass transfer equations reveal that, in order to generate a broad spectrum delivery system, nanoparticles with 100 nm diameter (or less) should be produced. However, experimental data reveal that, in some cases, even nanoparticles in the 100–1000 nm range are capable of producing substantial improvement in the bioavailability of the active ingredients. In most cases, this improvement in bioavailability seems to be linked to the direct uptake of the nanoparticle. Furthermore, direct nanoparticle uptake is controlled by the size and surface chemistry of the nanoparticle system. The use of this direct nanoparticle uptake, in particular for soluble but poorly absorbed ingredients, is one of the areas that needs to be explored in the future, as well as the potential side effects of these nanoparticle carriers.     

A Raman spectral study of stream waters and efflorescent salts in Rio Tinto, Spain

Acidic waters and sulfate-rich precipitates are found in mine tailings such as Rio Tinto (Huelva, SW, Spain). In this work we have characterized the chemical constituents of stream water and have identified some efflorescent salts and precipitates by means of Raman spectroscopy. Variable amounts of sulfate and bisulfate are found in the aqueous samples, suggesting changes in the acidity of the solutions. An estimation of the sulfate/water relative abundance is also given. Solid samples are readily identified as gypsum and as mixtures of hydrated hydroxysulfates belonging to the copiapite group. These results are consistent with previous works reporting the mineralogy and water composition of acid mine drainage-related sites, and proves the importance of Raman spectroscopy as a tool for accurate and noninvasive analyses of acid waters and associated geochemistry.     

A simple; efficient and environmentally friendly method for the extraction of pesticides from onion by matrix solid-phase dispersion with liquid chromatography-tandem mass spectrometric detection

An evaluation of the extraction of pesticides from onion by matrix solid-phase dispersion (MSPD) with the determination by liquid chromatography tandem mass spectrometry using electrospray as the ionization source (LC-ESI-MS/MS) was carried out. The performance of different sorbents, including reused C18 bonded silica, was evaluated. Different parameters affecting the extraction efficiency were evaluated, such as the type and amount of sorbent, the time of interaction after the fortification step, the time of sample dispersion and the elution solvent. The matrix effect regarding the recovery of the pesticides by MSPD was also investigated. The best results were obtained using 0.5 g of sample, 1.0 g reused C18, interaction time of 1 h, dispersion time of 5 min, and acetonitrile as the elution solvent. The method was validated by the fortification of the onion sample, free of pesticides, at different concentration levels (0.01, 0.1 and 1.0 mg kg⁻¹). Average recoveries ranged from 78.3 to 120.4% and relative standard deviation below 20% was obtained. Detection and quantification limits ranged from 0.003 to 0.03 mg kg⁻¹ and from 0.01 to 0.1 mg kg⁻¹, respectively.     

Measuring heat transfer during spray cooling using controlled induction-heating experiments and computational models

This paper presents a methodology combining experimental measurements with computational modeling to find the heat flux extracted during spray cooling of a metal surface. Controlled experiments are performed to impinge air-mist spray onto a metal probe surface while applying induction heating to follow a desired temperature history. A transient axisymmetric computational model of induction heating which couples electromagnetics and heat conduction has been developed and validated with a test problem. The model is calibrated to match transient dry measurements and then used to simulate a steady-state air-mist spray cooling experiment in order to quantify the heat extracted from the probe surface by the boiling water droplets. A detailed example is presented to illustrate this approach.     

Measurement of the tt production cross section in pp collisions at square root s = 1.96 TeV using missing E(T) + jets events with secondary vertex b tagging

We present a measurement of the tt production cross section in pp collisions at square root s = 1.96 TeV which uses events with an inclusive signature of significant missing transverse energy and jets. This is the first measurement which makes no explicit lepton identification requirements, so that sensitivity to W --> tau nu decays is maintained. Heavy flavor jets from top quark decay are identified with a secondary vertex tagging algorithm. From 311 pb(-1) of data collected by the Collider Detector at Fermilab, we measure a production cross section of 5.8 +/- 1.2(stat)(-0.7)(+0.9)(syst) pb for a top quark mass of 178 GeV/c2, in agreement with previous determinations and standard model predictions.     

Direct search for Dirac magnetic monopoles in pp collisions at square root s = 1.96 TeV

We search for pair-produced Dirac magnetic monopoles in 35.7 pb(-1) of proton-antiproton collisions at square root s = 1.96 TeV with the Collider Detector at Fermilab (CDF). We find no monopole candidates corresponding to a 95% confidence-level cross-section limit sigma < 0.2 pb for a monopole with mass between 200 and 700 GeV/c2. Assuming a Drell-Yan pair-production mechanism, we set a mass limit m > 360 GeV/c2.     

Search for charged Higgs bosons from top quark decays in pp collisions at square root s=1.96 TeV

We report the results of a search for a charged Higgs boson in the decays of top quarks produced in pp collisions at a center-of-mass energy of 1.96 TeV. We use a data sample corresponding to an integrated luminosity of 193 pb-1 collected by the upgraded Collider Detector at Fermilab. No evidence for charged Higgs production is found, allowing 95% C.L. upper limits to be placed on BR(t-->H+b) for different charged Higgs decay scenarios. In addition, we present in the minimal supersymmetric standard model (mH+/-, tanbeta) plane the first exclusion regions with radiative and Yukawa coupling corrections.     

Measurement of the ratios of branching fractions and

We report an observation of the decay B(O)(S) --> D(-)(s)pi(+) in pp collisions at radical S = 1.96 TeV using 115 pb(-1) of data collected by the CDF II detector at the Fermilab Tevatron. We observe 83 +/- 11(stat) B(O)(s) --> D(-)(s)pi(+) candidates, representing a large increase in statistics over previous measurements and the first observation of this decay at a pp collider. We present the first measurement of the relative branching fraction Beta(B(O)(s) --> D(-)(s)pi(+))/Beta(B(0) --> D(-)(pi)(+)) = 1.32 +/- 0.18(stat) +/- 0.38(syst). We also measure Beta(B(+) --> D(0)pi(+))/Beta(B(0) -->D(-)pi(+)) = 1.97 +/- 0.10(stat) +/- 0.21(syst), which is consistent with previous measurements.     

Search for large extra dimensions in the production of jets and missing transverse energy in pp collisions at square root of s = 1.96 TeV

We present the results of a search for new physics in the jets plus missing transverse energy data sample collected from 368 pb(-1) of pp collisions at square root of s = 1.96 TeV recorded by the Collider Detector at Fermilab. We compare the number of events observed in the data with a data-based estimate of the standard model backgrounds contributing to this signature. We observe no significant excess of events, and we interpret this null result in terms of lower limits on the fundamental Planck scale for a large extra dimensions scenario.