Gamma-ray tracking with the MARS detector

The feasibility of the entire process of -ray tracking is demonstrated experimentally for the first time. The accuracy of the results is tested by the capability for Doppler correction of -rays emitted in flight. The resolution of the 847.8 keV ( ) transition detected with the MARS detector after Coulomb excitation of a ⁵⁶Fe beam could be improved from 15 keV to below 5 keV (FWHM).Received: 28 October 2002, Published online: 2 March 2004PACS: 29.30.Kv X- and gamma-ray spectroscopy - 29.40.Gx Tracking and position-sensitive detectors - 29.40.Wk Solid-state detectorsC.A. Ur: On leave from: NIPNE, Bucharest, Romania.     

Taking stock of the occupational safety and health challenges of nanotechnology: 2000–2015

Engineered nanomaterials significantly entered commerce at the beginning of the 21st century. Concerns about serious potential health effects of nanomaterials were widespread. Now, approximately 15 years later, it is worthwhile to take stock of research and efforts to protect nanomaterial workers from potential risks of adverse health effects. This article provides and examines timelines for major functional areas (toxicology, metrology, exposure assessment, engineering controls and personal protective equipment, risk assessment, risk management, medical surveillance, and epidemiology) to identify significant contributions to worker safety and health. The occupational safety and health field has responded effectively to identify gaps in knowledge and practice, but further research is warranted and is described. There is now a greater, if imperfect, understanding of the mechanisms underlying nanoparticle toxicology, hazards to workers, and appropriate controls for nanomaterials, but unified analytical standards and exposure characterization methods are still lacking. The development of control-banding and similar strategies has compensated for incomplete data on exposure and risk, but it is unknown how widely such approaches are being adopted. Although the importance of epidemiologic studies and medical surveillance is recognized, implementation has been slowed by logistical issues. Responsible development of nanotechnology requires protection of workers at all stages of the technological life cycle. In each of the functional areas assessed, progress has been made, but more is required.     

X-Ray Structure of an Inclusion Compound of 5,5'-Biscalix[4]arene-hexabenzoate with Toluene

The structure of the 1:3 complex between 5,5'-biscalix[4]arene-hexabenzoateand toluene has been determined by a single crystal X-ray diffraction study. Thetwo calix[4]arene subunits of the 5,5'-biscalix[4]arene system are related by aninversion center and are joined by an eclipsed biphenyl para-para linkage. Each calix[4]arene moiety displays a 1,3-alternate conformation and includes a toluene molecule within two opposite benzoate groups, while a third toluene molecule lies close to a crystallographic inversion center.     

Separation of tetralins from long chain alkylbenzenes by kaolin-precoated capillary columns

Summary Pourous layer columns with kaolin as support have been used to separate 1,4-dialkyltetralins from long chain, C₁₀ to C₁₄ alkylbenzenes. A selective separation, of the tetralins from the alkylbenzenes due to the influence of the kaolin, has been obtained with columns with a low loading of PEG 1500 in a shorter time than on columns with mixed phases.     

Validation of a liquid chromatography-tandem mass spectrometry method to enable quantification of 3-iodothyronamine from serum

There is great interest lately in the availability of analytical methods for quantification of 3-iodothyronamine from blood and tissues. To date, no validated method for determination of 3-iodothyronamine from biological matrices has been described. Detailed in this report is an LC-MS/MS method that permits accurate and reproducible quantification of pharmacological concentrations of 3-iodothyronamine from rat serum, with a 0.0008 M lower limit of quantification. Endogenous 3-iodothyronamine was observed from rodent and human serum (0.2 mL) at the method limit of detection. In summary, the LC-MS/MS method enables quantification of circulating 3-iodothyronamine to allow examination of a relationship with biological activity.     

Phytochemical investigation of the needles of Abies nebrodensis (Lojac.) Mattei

Abstract

Abies nebrodensis (Lojac.) Mattei (Pinaceae) is a species living in a very small population only in a confined area of Sicily. In this study, the dichloromethane extract of the leaves was analyzed. Apart from three already known metabolites namely dehydroabietic acid; maltol; and rheosmin, previously detected in other species of Abies, a lanostane derivative was isolated. Its chemical structure was elucidated by means of extensive spectroscopic methods.     

Reuse of Food Waste: The Chemical Composition and Health Properties of Pomelo (Citrus maxima) Cultivar Essential Oils

The aim of the present study is to investigate the chemical profile, antioxidant activity, carbohydrate-hydrolysing enzyme inhibition, and hypolipidemic effect of essential oils (EOs) extracted from Sicilian Citrus maxima (pomelo) flavedo. Using gas-chromatography-mass spectrometry analysis (GC-MS) we analysed the Eos of five cultivars of C. maxima, namely, ‘Chadock’, ‘Maxima’, ‘Pyriformis’, ‘Terracciani’, and ‘Todarii’, and their blends. The antioxidant activity was performed by using a multi-target approach using 2,2′-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic acid (ABTS), 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing ability power (FRAP), and β-carotene bleaching tests. The α-amylase, α-glucosidase, and lipase-inhibitory activities were also assessed. GC-MS analyses revealed D-limonene as the main monoterpene hydrocarbon in all cultivars, albeit with different percentages in the range of 21.72–71.13%. A good content of oxygenated monoterpenes was detected for all cultivars, especially for ‘Todarii’. The analysis of the principal components (PCA), and related clusters (HCA), was performed to find chemo-diversity among the analysed samples. EOs from ‘Chadock’ and ‘Maxima’ were statistically similar to each other, and they differed from P3 in the smaller amount of sesquiterpene hydrocarbons, while the oils from ‘Terracciani’ and ‘Todarii’ were found to be chemically and statistically different. ‘Chadock’ EO was the most active to scavenge radicals (IC₅₀ values of 22.24 and 27.23 µg/mL in ABTS and DPPH tests, respectively). ‘Terracciani’ EO was the most active against both lipase and α-amylase, whereas the blends obtained by the combination (1:1 v/v) of C. maxima ‘Maxima’ + ‘Todarii’ were the most active against α-glucosidase. Generally, the blends did not exert a unique behaviour in potentiating or reducing the bioactivity of the pomelo EOs.     

Equivalence conditions between linear Lagrangian finite element and node‐centred finite volume schemes for conservation laws in cylindrical coordinates

A complete set of equivalence conditions, relating the mass‐lumped Bubnov–Galerkin finite element (FE) scheme for Lagrangian linear elements to node‐centred finite volume (FV) schemes, is derived for the first time for conservation laws in a three‐dimensional cylindrical reference. Equivalence conditions are used to devise a class of FV schemes, in which all grid‐dependent quantities are defined in terms of FE integrals. Moreover, all relevant differential operators in the FV framework are consistent with their FE counterparts, thus opening the way to the development of consistent hybrid FV/FE schemes for conservation laws in a three‐dimensional cylindrical coordinate system. The two‐dimensional schemes for the polar and the axisymmetrical cases are also explicitly derived. Numerical experiments for compressible unsteady flows, including expanding and converging shock problems and the interaction of a converging shock waves with obstacles, are carried out using the new approach. The results agree fairly well with one‐dimensional simulations and simplified models. Copyright © 2013 John Wiley & Sons, Ltd.     

Diester intrabridging of p-tert-butylcalix[8]arene and unexpected formation of the monospirodienone derivative

Reaction of p-tert-butylcalix[8]arene 1 with adipoyl chloride in the presence of NaH as the base yielded singly and doubly intrabridged esters 2-4 and 6. Surprisingly, calix[8]arene monospirodienone derivative 7 was also isolated, which was originated by O₂ oxidation. The conditions of this oxidation were optimized leading to a novel synthetic approach to calixarene monospirodienones based on the O₂/NaH/acyl-chloride oxidizing system. Xantheno calix[8]arenes 8-8a were obtained by rearrangement of 7.     

Chemical Compositions and Antioxidant Activities of Essential Oils,and Their Combinations,Obtained from Flavedo By-Product of Seven Cultivars of Sicilian Citrus aurantium L.

In this work, seven Citrus aurantium essential oils (EOs) derived from flavedo of cultivars ‘Canaliculata’, ‘Consolei’, ‘Crispifolia’, ‘Fasciata’, ‘Foetifera’, ‘Listata’, and ‘Bizzaria’ were investigated. EOs were also combined in 1:1 (v/v) ratio to identify possible synergism or antagonism of actions. GC-MS analysis was done to investigate Eos’ phytochemical profiles. The antioxidant activity was studied by using a multi-target approach based on FRAP, DPPH, ABTS, and β-carotene bleaching tests. A great difference was observed in EOs’ phytochemical profiles. d-limonene (33.35–89.17%) was the main monoterpene hydrocarbon, and α-Pinene, β-myrcene, and β-linalool were identified in almost all samples. Among EOs, only C3 showed high quantitative and qualitative variability in its chemical composition. The chemical diversity of EOs was also demonstrated by PCA and HCA statistical analysis. Samples C2, C4, C5, C6, and C7 were statistically similar to each other, while C1 and C3 were characterized as having a different amount of other compounds and oxygenated monoterpenes, respectively, with respect to the other EOs mentioned. The global antioxidant score (GAS) revealed that among the tested EOs, C. aurantium ‘Fasciata’ EO had the highest antioxidant potential, with a GAS value of −0.47, whereas among combinations, the EO obtained by mixing ‘Canaliculata’ + ‘Bizzaria’ was the most active. Comparison by theoretical and real data on inhibitory concentration (IC₅₀) and FRAP values did not reveal any significant effect of synergism or antagonism of actions to be valid in all biological applied tests. These findings, considered together, represent an important starting point to understand which compounds are responsible for the activities and their future possible industrial application.