Fuzzy supervised neurocontrol of electrohydraulic servos

The work presents theoretical and experimental investigations concerning the neuro-fuzzy control of electrohydraulic servos. The control algorithm is built around a neurocontroller designed to optimize a performance index. Whenever the neurocontrol saturates or a system performance parameter decreases, the control scheme switches to a feasible and reliable fuzzy logic control. In accordance with simulation studies developed in previous works of the authors, the neuro-fuzzy controlled system proves often to be better than the corresponding classical PI or LQG systems. We emphasize that the entire control synthesis is thought as a model free approach, thus ensuring reduced design complexity and focusing on increased system robustness. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ultrastructural Damages to H1N1 Influenza Virus Caused by Vapor Essential Oils

Influenza viruses are transmitted from human to human via airborne droplets and can be transferred through contaminated environmental surfaces. Some works have demonstrated the efficacy of essential oils (EOs) as antimicrobial and antiviral agents, but most of them examined the liquid phases, which are generally toxic for oral applications. In our study, we describe the antiviral activity of Citrus bergamia, Melaleuca alternifolia, Illicium verum and Eucalyptus globulus vapor EOs against influenza virus type A. In the vapor phase, C. bergamia and M. alternifolia strongly reduced viral cytopathic effect without exerting any cytotoxicity. The E. globulus vapor EO reduced viral infection by 78% with no cytotoxicity, while I. verum was not effective. Furthermore, we characterized the EOs and their vapor phase by the head-space gas chromatography–mass spectrometry technique, observing that the major component found in each liquid EO is the same one of the corresponding vapor phases, with the exception of M. alternifolia. To deepen the mechanism of action, the morphological integrity of virus particles was checked by negative staining transmission electron microscopy, showing that they interfere with the lipid bilayer of the viral envelope, leading to the decomposition of membranes. We speculated that the most abundant components of the vapor EOs might directly interfere with influenza virus envelope structures or mask viral structures important for early steps of viral infection.     

Syntheses and characterization of nickel(II) dithiocarbamate complexes containing NiS4 and NiS2PN moieties: Nickel sulphide nanoparticles from a single source precursor

In this study, ammonium N-benzyldithiocarbamate was synthesized and used to prepare homoleptic Ni(II) bis(N-benzyldithiocarbamate) (1) and heteroleptic Ni(II) complexes involving isocyanate (2) and cyanide (3) ions. The complexes were characterized by elemental analysis, Fourier transform infra-red (FTIR), and NMR (¹H and ¹³C) spectroscopic techniques. Complex 2 was further characterized by single crystal X-ray diffraction analysis. The FTIR showed bidentate co-ordination for all the complexes as the v(CN) stretching frequency were in the 980–1050 cm^?1 region without any splitting. Thermal decomposition profile of the complexes showed decomposition resulting in the formation of nickel sulphides. The homoleptic complex 1 was utilized as single source precursor (SSP) to prepare Nickel sulphide nanoparticles. The synthesis of the nanoparticles was conducted using different capping molecules (with various alkyl chain lengths), and at different reaction temperature and time. Pure phase Heazlewoodite (Ni₃S₂) nanoparticles were obtained from the X-ray diffraction study. The TEM analysis showed that the type of capping agent, reaction temperature, and time of reaction have significant effect on the morphology and size of the nanoparticles. The optical properties of the nanoparticles were studied using absorption and fluorescence spectroscopies, and they displayed evidence of quantum confinement effect.     

Early transition-metal perfluoroalkyl complexes

Elusive early transition-metal perfluoroalkyl complexes have been isolated and structurally characterized for the first time. Trifluoromethyltrimethylsilane, CF3SiMe3, serves as an excellent trifluoromethyl group-transfer reagent and reacts with the known Ti(IV) fluoride complex Cp2TiF2 to yield the novel Ti(IV) trifluoromethyl fluoride compound, Cp2Ti(CF3)(F) (1). Reaction of complex 1 with trimethylsilyltriflate (Me3SiOTf) affords the Ti(IV) trifluoromethyl triflate complex Cp2Ti(CF3)(OTf) (2). Both titanium perfluoroalkyl compounds have been characterized spectroscopically and by single-crystal X-ray analysis. The Ti-CF3 linkage in these complexes is remarkably robust and shows no evidence of an alpha-fluoride interaction (Ti...F-CF2) between the electrophilic Ti(IV) metal center and any of the C-F bonds in the trifluoromethyl group in the solid state or in solution.     

1H and 13C NMR spectral data of bioactive cage‐like polycyclic compounds

Bioactive cage‐like polycyclic compounds have attracted the attention of several research groups because of their unique appearance and their biological activities. Their structures were established on the basis of ¹H NMR and ¹³C NMR spectroscopic data. The ¹H and ¹³C signal assignments and most homonuclear hydrogen coupling constants were assigned by use of techniques such as 1D ¹H and ¹³C NMR and 2D gCOSY, non‐edited gHSQC and gHMBC. The gNOESY experiments proved the endo‐stereochemistry. Copyright © 2010 John Wiley & Sons, Ltd.     

An evaluation of infrared microwindows for ozone retrievals using the Eureka Bruker 125HR Fourier transform spectrometer

A Bruker 125HR Fourier transform spectrometer was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut, Canada in the summer of 2006 to study atmospheric composition. Using the optimal estimation method, typically over a limited spectral region called a microwindow, information about the vertical distribution of trace gas species that have absorption bands in the mid-infrared spectral range can be retrieved. Total and partial columns can also be determined to show the temporal evolution of the target gas. For ozone in particular, retrievals have been performed using several of its many mid-infrared absorption features, resulting in a lack of consistency in the literature in the microwindows chosen for retrievals. This work focuses on the optimization of the ozone retrieval, assessing a set of 22 microwindows between 780 and 3052 cm⁻¹ to determine which is best suited to conditions at Eureka. The 1000-1004.5 cm⁻¹ spectral interval is shown to be the most sensitive to both the stratosphere and troposphere. This microwindow gives the highest number of degrees of freedom for signal (∼7 for total column), and the smallest total error (4.3%) compared with 21 other spectral regions. Retrievals performed with this microwindow agree well with results obtained from other instruments on-site. Total column ozone measured by the Bruker 125HR in this microwindow agreed to 2% with two other Fourier transform spectrometers, to 0.7% with a Brewer spectrophotometer, to 8% with a SAOZ UV-VIS spectrometer, and to 7% with ozone sondes.     

Enantioselective benzylic hydroxylation of indan and tetralin with Pseudomonas monteilii TA-5

A set of 22 toluene- and ethylbenzene-degrading strains were screened for the enantioselective benzylic hydroxylation of indan and tetralin, and Pseudomonas monteilii TA-5 was discovered as an active and selective biocatalyst for such hydroxylations. Cells of P. monteilii TA-5 can be easily grown to a high density and demonstrated a specific hydroxylation activity of 24 U/g cdw (cell dry weight). Conditions for the hydroxylation of indan 1a and tetralin 1b with resting cells of this strain were optimized, to give the corresponding (R)-1-indanol 2a and (R)-1-tetralol 2b in 99% ee and 62–67% yields, respectively. No significant product inhibition was observed, and biohydroxylation with cell-free extracts suggested that the responsible hydroxylase is a soluble enzyme depending on either NADH or NADPH. Preparative biohydroxylation was demonstrated with resting cells as biocatalysts, affording (R)-2a in 99% ee and 65% yield, and (R)-2b in 99% ee and in 63% yield, respectively.     

Conformationally locked isostere of phosphoSer-cis-Pro inhibits Pin1 23-fold better than phosphoSer-trans-Pro isostere

Stereoisomeric cis and trans substrate analogues for Pin1 were designed and synthesized. The central phosphoSer-Pro core of the Pin1 substrate was replaced by cis and trans amide isosteres in Ac-Phe-Phe-pSer-Psi[(Z and E)CH=C]-Pro-Arg-NH(2), 1 and 2, peptidomimetics. They were synthesized on solid phase in 17% yield for the cis analogue 1, and 16% yield for the trans analogue 2. A second trans amide isostere with a C-terminal N-methylamide 3 was synthesized in 7% yield. The protease-coupled Pin1 assay showed that all three compounds inhibited the Pin1 peptidyl-prolyl isomerase (PPIase) enzymatic activity. The cis isostere 1 was 23 times more potent (K(i) = 1.74 +/- 0.08 muM) than its trans counterpart 2 (K(i) = 40 +/- 2 muM) in competitive inhibition of Pin1. These results suggest that the catalytic site of Pin1 binds cis substrates more tightly in aqueous solution. Antiproliferative activity toward the A2780 human ovarian cancer cell line by the cis and trans analogues correlates with Pin1 inhibition results.     

Steric course of some cyclopropanation reactions of L-threo-hex-4-enopyranosides

Completely protected 4-deoxy-α-L-threo-hex-4-enopyranosides 1c,d undergo the dichlorocarbene addition affording exclusively diastereomeric adducts 5c,d with the cyclopropane ring anti to the C-3 alkyloxy substituent, while the reaction with 3-unprotected derivatives 1a,b affords a mixture of syn and anti derivatives. Under the Simmons-Smith cyclopropanation adducts 2a-d with a syn stereochemistry are obtained. Starting from 5b, the cyclopropanated sugar 3b is obtained by reduction with LiAlH₄, thus the two diastereomers 2b and 3b can be stereoselectively obtained through the two different pathways. For a useful comparison, 4-deoxy-β-L-threo-hex-4-enopyranoside 1e was also subjected to the above two cyclopropanation methods affording the expected cycloadduct 2e and a diastereomeric mixture of dichlorocycloadducts 4e and 5e (4e/5e=2.8:1).     

Liquid chromatographic determination of S-adenosyl-L-methionine in dietary supplement tablets

A simple and reliable liquid chromatographic method was developed for the determination of S-adenosyl-L-methionine (SAM) in dietary supplement tablets. SAM in products was extracted with a phosphate buffer and separated from the mixture on a reversed-phase C8 column by ion-pair chromatography. A gradient mobile phase containing phosphate buffer, sodium octanesulfonate as the ion-pair reagent, and acetonitrile at a flow rate of 1.2 mL/min was used in the analysis. The UV detection wavelength was set at 257 nm. The calibration curve was linear over a range of 75-375 microg/mL for the SAM active ion with R2 = 0.9999. Replicate tests indicated good reproducibility of the method with a relative standard deviation of 0.9% (n = 8). The multiple extractions and recoveries from fortified products showed the high accuracy of the analysis. The use of the acidic buffer for SAM extraction and elution and the use of a fresh standard for each calibration to counteract the instability of the SAM compound significantly improved the accuracy of the method.