Detection of freeze injury in oranges by magnetic resonance imaging of moving samples

Magnetic resonance imaging (MRI) is applied for on-line inspection of fruits. The aim of this work is to address the applicability of MRI for freeze injury detection in oranges directly on a distribution chain. Undamaged and damaged oranges are conveyed at 50 and 100 mm/s by a specially designed conveyor within a 4.7 T spectrometer obtaining fast low-angle shot images. An automatic segmentation algorithm is proposed that allows the discrimination between undamaged and damaged oranges.     

Chiral separation of gamma-butyrolactone derivatives by gas chromatography on 2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl-beta-cyclodextrin

The chiral GC separation of 2-alkyl-2-keto-gamma-butyrolactone derivatives and their alcohol analogs using 2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl-beta-cyclodextrin (DIMETBCD) as chiral selector was discussed. The results, supported by the ketone preliminary molecular modelling calculations, suggest that the chiral recognition for DIMETBCD depends more on the geometry than on the polarity of the alkyl substituents on the butyrolactones. Hydrogen bonds and alkyl group steric effects should be an important function of the alcohol chiral recognition for DIMETBCD. Comparison of the retention times of the alcohol derivatives, in achiral and chiral stationary phases, suggests a specific structural effect for the cyclodextrin selctor.     

Synthesis and antimicrobial activities of silver(I) sulfanylcarboxylates. Structural isomers with identically or unequally coordinated Ag centers in an Ag4S4 ring

We have investigated the reactions of silver nitrate and 3-(aryl)-2-sulfanylpropenoic acids [H(2)xspa, x: p = 3-phenyl-, f = 3-(2-furyl)-, t = 3-(2-thienyl)-, py = 3-(2-pyridyl)-] and 2-cyclopentylidene-2-sulfanylacetic acid (H(2)L) in 1 : 1 and 2 : 1 molar ratios. The 1 : 1 molar ratio gave compounds of type [Ag(HL)]; reaction of these compounds with diisopropylamine and NaOH gave [HQ][Ag(L)] (HQ = diisopropylammonium) and Na[Ag(L)] x H(2)O, respectively. These compounds, as well as those of type [Ag(2)(L)] obtained with the 1 : 2 molar ratio, were isolated and characterized by IR and NMR ((1)H and (13)C) spectroscopy. (109)Ag NMR spectroscopy and ESI-MS spectrometry were also used in some cases. The crystal structures of [HQ][Ag(pspa)] (11), in which the presence of structural isomers was detected, and [HQ][Ag(cpa)] (15) were determined by X-ray diffractometry. The antimicrobial activity of the complexes against E. coli, S. aureus, B. subtilis, P. aeruginosa/Resistant P. aeruginosa, and C. albicans was tested.     

Effect of S–Se Bioisosteric Exchange on Affinity and Intrinsic Efficacy of Novel N-acylhydrazone Derivatives at the Adenosine A2A Receptor

In this work, we evaluated the conformational effect promoted by the isosteric exchange of sulfur by selenium in the heteroaromatic ring of new N-acylhydrazone (NAH) derivatives (3–8, 13, 14), analogues of the cardioactive compounds LASSBio-294 (1) and LASSBio-785 (2). NMR spectra analysis demonstrated a chemical shift variation of the iminic Csp² of NAH S/Se-isosters, suggesting a stronger intramolecular chalcogen interaction for Se-derivatives. To investigate the pharmacological profile of these compounds at the adenosine A_2A receptor (A_2AR), we performed a previously validated functional binding assay. As expected for bioisosteres, the isosteric-S/Se replacement affected neither the affinity nor the intrinsic efficacy of our NAH derivatives (1–8). However, the N-methylated compounds (2, 6–8) presented a weak partial agonist profile at A_2AR, contrary to the non-methylated counterparts (1, 3–5), which appeared as weak inverse agonists. Additionally, retroisosterism between aromatic rings of NAH on S/Se-isosters mimicked the effect of the N-methylation on intrinsic efficacy at A_2AR, while meta-substitution in the phenyl ring of the acyl moiety did not. This study showed that the conformational effect of NAH-N-methylation and aromatic rings retroisosterism changed the intrinsic efficacy on A_2AR, indicating the S/Se-chalcogen effect to drive the conformational behavior of this series of NAH.     

Quenching effects on pulsed photoacoustic signals in NO2–air samples

A theoretical expression for the pulsed photoacoustic signal amplitude from NO₂–air mixtures is deduced based on a two-level system and the inhomogeneous wave equation, in the limit where the V-T relaxation time is longer than the laser pulse width (low buffer pressure). In this time limit, the photoacoustic signal from NO₂, at constant pressure, after excitation by pulses from a Nd:YAG laser at 532 nm, is measured at different buffer pressures. The relaxation rates are obtained by measuring the quenching of visible fluorescence induced by the same laser. The experimental dependence of the photoacoustic signal amplitude on air pressure shows a very good agreement with the model, where the measured relaxation rates are included.     

The final statesl ± K ± K ± X in jets as signatures ofB_s^0 - \bar B_s^0 mixings

Significant mixing is expected between the neutral bottom mesons \(B_s^0 - \bar B_s^0 \) in the standard model of weak interactions. We propose measurements of the processes \(\left\{ {\begin{array}{*{20}c} {e^ + e^ - } \\ {p\bar p} \\ \end{array} } \right\} \to \begin{array}{*{20}c} {b\bar b} \\ {} \\ \end{array} \to l^ + K^ - K^ - X\) as a measure of such mixing. Rates are presented for energetic bottom quark jets, produced ine ⁺ e ^? annihilation.     

Design,synthesis,characterization,cytotoxic and structure activity relationships of novel Ru(Ⅱ) complexes

Platinum containing compounds have shown antineoplastic potential, but their clinical applications have been limited by high toxicity. Ruthenium containing complexes have long been known to be well suited for biological applications, and have long been utilized as replacements to popular platinum based-drugs. Here, we report a novel series of ruthenium(II) arene compounds bearing thiosemicarbazone and isonicotinylhydrazone ligands with potent anticancer activity their structure activity relationships and apoptosis was studied. The cytotoxic activity of the new ruthenium(II) arene compounds has been evaluated in several cell lines (Molt 4/C8, L1210, CEM, HL60 and BEL7402). Among them, ten complexes were found to be excellent in vitro growth inhibitory activity against various cell lines with IC50 in the sub-micromolar range.     

Synthesis of pyrazole derivatives as potential bioisosteres of thromboxane-synthetase inhibitors

A series of ω-carboalkenyl pyrazole derivatives have been synthesized as potential thromboxane-synthetase inhibitors considering the close bioisosteric relationship between the pyrazole ring and other heteroaromatic carboalkenyl compounds exhibiting inhibitory activity. (E)-7-(1-Phenylpyrazol-4-yl)hept-2-enoic acid (4b) were prepared in 28% overall yield from its minor bis-homologue, (E)-5-(1-phenylpyrazol-4-yl)pent-2-enoic acid (4a) , obtained from 4-formyl-1-phenylpyrazole (6) in 17% overall yield. Compounds 4a, 4b, 7, 8 and 13 were screened for their ability to inhibit the in vitro rabbit blood platelet aggregation induced by collagen using the Born test. Among the active compounds 4a exhibited an important inhibition at 1 μM concentration.