Optical diagnosis of peritoneal metastases by infrared microscopic imaging

Fourier transform infrared (FTIR) spectroscopy is nowadays widely accepted as a technique with high potential for diagnosis of cancerous tissues. This study presents an example of the investigation of peritoneal metastases by FTIR microimaging. Peritoneal malignancies are generally secondary localizations of primary visceral cancers such as ovarian, stomach or colon cancers. By analysing simultaneously both formalin-fixed paraffin-embedded and frozen specimens, we examined malignant and non-malignant (i.e. fibrotic and cicatricial) peritoneal lesions. Paraffin-embedded tissues were analysed without any previous dewaxing. Multivariate statistical approaches, based on the classification of infrared data by hierarchical cluster analysis, allowed the discrimination of these various samples. Microimaging also permits the revelation of the heterogeneity of the tissue: it was possible to localize precisely the cancerous areas, and to distinguish, on the basis of their spectral signatures, the peritumoral neighbouring connective tissue close to the carcinomatous areas from the connective tissue distant from the cancerous areas. These spectral differences could be useful as complementary information to study molecular changes associated with the malignancy.     

A Step-Forward Method of Quantitative Analysis of Enzymatically Produced Isomaltooligosaccharide Preparations by AEC-PAD

In this paper, anion exchange chromatography coupled with pulsed amperometric detection has been successfully applied for the fine analysis of isomaltooligosaccharides (IMO) syrups where previous reported methods suffered from a lack of homologue oligosaccharides resolution. These syrups are made of a very complex mixture of glucose oligosaccharides characterized at the same time by their DP value (from 2 to ~15) and linkage types [α-(1–2, 3 or 6) and non-IMO α-(1–4)] and position. A mix of available commercial standards (17 species) was completely separated on a CarboPac PA-100 column at a flow rate of 1 mL min^?1 and with a gradient of sodium acetate in 100 mM sodium hydroxide. The method was validated according to calibration curve, precision, recovery tests, limits of detection and quantitation. Calibration curves presented correlation coefficients greater than 0.98. The analytical method has been applied on real syrups, keeping a high performance separation of structurally close molecules and giving, for six determinations, very low relative SD for the available standard molecules (0.3–5.8%). The accuracy of the proposed method was tested by recovery measurements: first by spiking maltose on three different syrups and then by spiking six different sugar standards (20, 50 and 75% of the initial content) on a single syrup. Good recovery results (respectively, 96.5–99.7 and 97.1–102.7%) were found. The method was found sensible with limits of detection (signal-to-noise ratio of 3) between 0.048 and 0.124 μg mL^?1 and limits of quantification (signal-to-noise ratio of 10) between 0.159 and 0.412 μg mL^?1.     

The reductive dimerization of some 1,3-dienes and of 1,3,5-cycloheptatriene in the presence of trimethylchlorosilane: a DFT investigation

Treatment of 1,3-dienes and 1,3,5-cycloheptatriene by chlorotrimethylsilane in the presence of wire of lithium led mainly to reductive dimerization with formation of bis(allylsilane) derivatives. Bis-silyl compounds obtained: from 1,3-butadiene, 1,8-bis(trimethylsilyl)-2,6-octadiene (70%); from isoprene, (Z,Z)-2,7-dimethyl-1,8-bis(trimethylsilyl)-2,6-octadiene (44%) and 2,6-dimethyl-1,8-bis(trimethylsilyl)-2,6-octadiene (19%); from butadiene-isoprene mixture (1:1), 3-methyl-1,8-bis(trimethylsilyl)-2,6-octadiene (55%); from 2,3-dimethylbutadiene, (E,E)-2,3,6,7-tetramethyl-1,8-bis(trimethylsilyl)-2,6-octadiene (36%), from 1,3-cyclohexadiene, 4,4′-bis(trimethylsilyl)-bicyclohexyl-2,2′-diene (48%); from 1,3,5-cycloheptatriene, 1,1′-bi[(S^∗,S^∗)-6-(trimethylsilyl)cyclohepta-2,4-dien-1-yl] (53%). The structure of the various intermediates (radical anion, dianion, silylated radical, silylated anion) has been established by calculations at the B3LYP/6-311++G(d,p) level of theory with zero-point energy correction. These results are in accordance with a pathway including the formation of a radical anion, its silylation furnishing to a γ-silylated allylic radical followed by a dimerization reaction in the head to head manner.     

Polyaniline-nylon-6 electrospun nanofibers for headspace adsorptive microextraction

A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200 nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography–mass spectrometry (GC–MS). Various parameters affecting the extraction and desorption processes were optimized. The developed method proved to be convenient and offers sufficient sensitivity and a good reproducibility. Limits of detection achieved for CBs with the developed analytical procedure ranged from 19 to 33 ng L^?1, while limits of quantification were from 50 to 60 ng L^?1. The relative standard deviations (RSD) at a concentration level of 0.1 ng mL^?1 and 1 ng mL^?1 were in the range of 8–14% and 5–11% (n = 3), respectively. The calibration curves of analytes were investigated in the range of 50–1000 ng L^?1 and R² between 0.9739 and 0.9932 were obtained. The developed method was successfully applied to the extraction of selected CBs from tap and river water samples. The relative recovery (RR) percentage obtained for the spiked real water samples at 0.1 ng mL^?1 and 1 ng mL^?1 level were 93–103% and 95–104%, respectively. The whole procedure showed to be conveniently applicable and quite easy to handle.     

Synthesis of novel β-lactams bearing an anthraquinone moiety,and evaluation of their antimalarial activities

A novel series of β-lactams bearing an anthraquinone moiety have been synthesized from imines derived from anthraquinone-2-carbaldehyde and ketenes by a [2+2] cycloaddition reaction. The cycloadducts were fully characterized and evaluated for their antimalarial activities against Plasmodium falciparum K14 resistant strain and showed moderate to excellent EC₅₀ values varying from 9 to 50 μM.     

Sur les phases de type clathrate du silicium et des éléments apparentés (C, Ge, Sn) : Une approche historique

Clathrate-type phases of silicon and related elements (C, Ge, Sn). This review article relates the history and the recent development of clathrate-type compounds of silicon and related elements (carbon, germanium, tin). Their cage-like structures are identical to those of the gas and liquid hydrates, as well as the silica-based clathrasils. Long time considered as simple crystallographic curiosities, their interest was drastically increased after the discovery of the fullerene forms of carbon. From that time they have been intensively studied for their interesting properties in so various topics as superconducting materials, wide gap semiconductors, super-hard and thermoelectric materials.     

Multiresidue determination of pesticides from aquatic media using polyaniline nanowires network as highly efficient sorbent for microextraction in packed syringe

A simple, rapid and sensitive method based on microextraction in packed syringe (MEPS), in combination with gas chromatography–mass spectrometry (GC–MS) was developed. Polyaniline (PANI) nanowires network was synthesized and used as sorbent of MEPS for the multiresidue determination of selected analytes from triazine, organochlrorine and organophosphorous pesticides in aqueous samples. The PANI nanowires network was prepared using soft template technique and its characterization was studied by scanning electron microscopy (SEM). The presence of micelles in this methodology showed to be an important parameter in shaping the growing polymer. Hexadecyltrimethylammonium bromide (HTAB) was used as structure directing agent in PANI preparation procedure and this was led to the formation of nanowires with diameters ranging from 35 nm to 45 nm. The synthesized PANI nanowires network showed higher extraction capability in comparison with the bulk PANI. Important parameters influencing the extraction and desorption processes including desorption solvent, elution volume, draw–eject cycles of sample, draw–eject mode, pH effect and amount of sorbent were optimized. Limits of detection were in the range of 0.07–0.3 ng mL⁻¹ using time scheduled selected ion monitoring (SIM) mode. The linearity of method was in the range from 0.5–200 ng mL⁻¹ to 0.2–1000 ng mL⁻¹. The method precision (RSD %) with three replicates were in the range of 5.3–18.4% at the concentration level of 5 ng mL⁻¹. The developed method was successfully applied to the Zayandeh-rood river water samples and the matrix factor obtained for the spiked real water samples were in the range of 0.79–0.94.