Fast and reversible CO2 quartz crystal microbalance response of vinylimidazolium‐based poly(ionic liquid)s

A series of poly(ionic liquid)s (pILs) based on the 1‐vinyl‐3‐hexylimidazolium polymerizable cation and on the bis(trifluoromethylsulfonyl)imide, nonafluoro‐1‐butanesulfonate, dodecylbenzenesulfonate, heptadecafluorooctanesulfonate, and 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11‐heptadecafluoroundecanoate anions have been synthesized and characterized. Their sorption/desorption response towards CO₂ has been tested through quartz crystal microbalance investigations. The obtained results show that all of the pILs here reported are featured by peculiar CO₂ sorption properties as they display fast and linear response, reversibility without any memory effect, and reproducibility, suggesting that anion plays a key role in determining sensitivity. Copyright © 2011 John Wiley & Sons, Ltd.     

Validation of the Soleris E. coli method for detection and semi-quantitative determination of Escherichia coli in foods

The performance of the Soleris E. coli method was compared with that of the ISO 7251 most probable number (MPN) and detection reference methods for Escherichia coli. The Soleris E. coli method is a growth-based, rapid, automated system composed of temperature-controlled incubation chambers and photodiode-based optical detection devices for measurement of color changes in a prepared medium vial. A dilution of the test sample homogenate is inoculated directly into the vial. Products of E. coli metabolism alter the color of the medium over time, and this change is monitored by the Soleris instrument. The test is used in a dilute-to-specification or specification monitoring manner in which the result is positive or negative around a desired cutoff (in CFU/g) determined by the dilution and volume of sample homogenate added to the vial. Alternatively, the test is used for zero tolerance determinations (e.g., absence in 25 g) by performing an off-line pre-enrichment step followed by transfer of a portion of the pre-enrichment culture to the Soleris vial. Six E. coli strains originating from food sources were inoculated individually into six food commodities: frozen green beans, Echinacea powder, cocoa powder, sweetened condensed milk, pasteurized liquid egg, and shredded mozzarella cheese. Uninoculated samples were included in each trial. The results obtained by the ISO 7251 detection method and the Soleris E. coli method were shown to be in agreement by Chi-square analysis when the presence of E. coli was determined in 25 g of sample. Results from the Soleris E. coli dilute-to-specification method and the ISO 7251 MPN method were found to be in agreement by probability of detection statistical analysis. In inclusivity testing, 52 of 53 E. coli strains were detected within 24 h. Only a non-thermoduric strain of serotype O157:H43 was not detected. In exclusivity testing, all 31 strains tested produced negative results. Results of ruggedness experiments show that accurate results can be obtained even when the operating temperature of the Soleris instrument is set beyond normal tolerances. The internal and independent laboratory studies demonstrated that the Soleris E. coli method could be successfully utilized as an alternative to the reference methods, with a significant time savings of 2 to 3 days.     

The interrelation between acoustic context effects and available response categories in speech sound categorization

In an investigation of contextual influences on sound categorization, 64 Peruvian Spanish listeners categorized vowels on an /i/ to /e/ continuum. First, to measure the influence of the stimulus range (broad acoustic context) and the preceding stimuli (local acoustic context), listeners were presented with different subsets of the Spanish /i/-/e/ continuum in separate blocks. Second, the influence of the number of response categories was measured by presenting half of the participants with /i/ and /e/ as responses, and the other half with /i/, /e/, /a/, /o/, and /u/. The results showed that the perceptual category boundary between /i/ and /e/ shifted depending on the stimulus range and that the formant values of locally preceding items had a contrastive influence. Categorization was less susceptible to broad and local acoustic context effects, however, when listeners were presented with five rather than two response options. Vowel categorization depends not only on the acoustic properties of the target stimulus, but also on its broad and local acoustic context. The influence of such context is in turn affected by the number of internal referents that are available to the listener in a task.     

Analysis of breath by proton transfer reaction time of flight mass spectrometry in rats with steatohepatitis induced by high-fat diet

Breath testing has been largely used as a diagnostic tool, but the difficulties in data interpretation and sample collection have limited its application. We developed a fast (< 20?s), on-line, non-invasive method for the collection and analysis of exhaled breath in awake rats based on proton transfer reaction time of flight mass spectrometry (PTR-ToF-MS) and applied it to investigate possible relationships between pathologies induced by dietary regime and breath composition. As a case study, we investigated rats with dietary induced non-alcoholic steatohepatitis (NASH) and modifications induced by coffee addition to the diet. We considered two different diets (standard and high fat) complemented with two different drinking possibilities (water or decaffeinated coffee) for a total of four groups with four rats each. Several spectrometric peaks were reliable markers for both dietary fat content and coffee supplementation. The high resolution and accuracy of PTR-ToF-MS allowed the identification of related compounds such as methanol, dimethyl sulphide, dimethyl sulphone and ammonia. In conclusion, the rapid and minimally invasive breath analysis of awake rats permitted the identification of markers related to diet and specific pathologic conditions and provided a useful tool for broader metabolic investigations. Copyright ? 2012 John Wiley & Sons, Ltd.     

Design,Synthesis and Antiparasitic Evaluation of Click Phospholipids

A library of seventeen novel ether phospholipid analogues, containing 5-membered heterocyclic rings (1,2,3-triazolyl, isoxazolyl, 1,3,4-oxadiazolyl and 1,2,4-oxadiazolyl) in the lipid portion were designed and synthesized aiming to identify optimised miltefosine analogues. The compounds were evaluated for their in vitro antiparasitic activity against Leishmania infantum and Leishmania donovani intracellular amastigotes, against Trypanosoma brucei brucei and against different developmental stages of Trypanosoma cruzi. The nature of the substituents of the heterocyclic ring (tail) and the oligomethylene spacer between the head group and the heterocyclic ring was found to affect the activity and toxicity of these compounds leading to a significantly improved understanding of their structure–activity relationships. The early ADMET profile of the new derivatives did not reveal major liabilities for the potent compounds. The 1,2,3-triazole derivative 27 substituted by a decyl tail, an undecyl spacer and a choline head group exhibited broad spectrum antiparasitic activity. It possessed low micromolar activity against the intracellular amastigotes of two L. infantum strains and T. cruzi Y strain epimastigotes, intracellular amastigotes and trypomastigotes, while its cytotoxicity concentration (CC₅₀) against THP-1 macrophages ranged between 50 and 100 μM. Altogether, our work paves the way for the development of improved ether phospholipid derivatives to control neglected tropical diseases.     

Extremal versus additive Matérn point processes

In the simplest Matérn point processes one retains certain points of a Poisson point process in such a way that no pairs of points are at distance less than a threshold. This condition can be reinterpreted as a threshold condition on an extremal shot–noise field associated with the Poisson point process. This paper is focused on the case where one retains points that satisfy a threshold condition based on an additive shot–noise field of the Poisson point process. We provide an analytical characterization of the intensity of this class of point processes and we compare the packing obtained by the extremal and additive schemes and certain combinations thereof.     

The ontological function of first-order and second-order corpuscles in the chemical philosophy of Robert Boyle: the redintegration of potassium nitrate

Although Boyle has been regarded as a champion of the seventeenth century Cartesian mechanical philosophy, I defend the position that Boyle’s views conciliate between a strictly mechanistic conception of fundamental matter and a non-reductionist conception of chemical qualities. In particular, I argue that this conciliation is evident in Boyle’s ontological distinction between fundamental corpuscles endowed with mechanistic properties and higher-level corpuscular concretions endowed with chemical properties. Some of these points have already been acknowledged by contemporary scholars, and I actively engage with their ideas in this paper. However I attempt to contribute to the debate over Boyle’s mechanical philosophy by arguing that Boyle’s writings suggest an emergentist, albeit still mechanistic, notion of chemical properties. I contrast Boyle’s views against those of strict reductionist mechanical philosophers, focusing on the famous debate with Spinoza over the redintegration of niter, and argue that Boyle’s complex chemical ontology provides a more satisfactory understanding of chemical phenomena than is provided by a strictly reductionist and Cartesian mechanical philosophy.     

Polyclonal antibodies: a cheap and efficient tool for screening of enantioselective catalysts

Enantioselective polyclonal antibodies have been produced and characterized to develop a high-throughput screening method for lipase activity fingerprinting, with a view to the enantioselective hydrolysis of azlactones.     

Phytochemical and antioxidant-related investigations on bark of Abies spectabilis (D. Don) Spach. from Nepal

The bark of several coniferous species, a waste product of the timber industry, contains significant amounts of natural antioxidants. In our ongoing studies of Nepalese medicinal plants, we examined the bark from Abies spectabilis as the starting material for extracting antioxidant compounds. In vitro antioxidant activity evaluated by means of three antioxidant methods, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), Briggs-Rauscher oscillating reaction (BR) and Trolox Equivalent Antioxidant Capacity (TEAC) and total phenol contents with the Folin-Ciocalteau reagent; the ferrous iron chelating capacity was also assessed. The methanol extract of A. spectabilis showed significant antioxidant activity and polyphenol contents (IC(50) 4.13 μg/mL, 0.20 μg/mL eq. resorcinol, 4.22 mM eq. Trolox, 3.9 μg/g eq. gallic Acid in the DPPH, BR, TEAC and Folin-Ciocalteau tests, respectively) and weak Fe(2+) chelating capacity. Phytochemical studies were also carried out with 1D- and 2D NMR experiments and DI-ESI-MS, HPLC-DAD and LC-MSn measurements. Oligomeric C-type proanthocyanidins, mainly trimeric gallocatechin derivatives, were the most abundant compounds (16% of extract expressed as procyanindin B1). Gallocatechin oligomers (up to six units) and prodelphynidin-gallocatechin polymers were also identified in the extract. Prodelphynidin B4, cyclograndisolide and trans-docosanil ferulate were also isolated and characterized by NMR and MS spectroscopy.