1H-NMR Metabolic Profiling and Antioxidant Activity of Saffron (Crocus sativus) Cultivated in Lebanon

Despite the beneficial health properties shown by Lebanese saffron, its qualitative and quantitative composition has never been investigated before. In the present study, NMR spectroscopy, together with antioxidant activity assays, were applied to evaluate the chemical composition of saffron samples of different geographical origins (Lebanon, Italy, Iran, and India) and to categorize the Lebanese saffron for the first time. The distinction between Lebanese saffron and that produced in other countries was attributed to its higher linolenic and linoleic fatty acids, glucose and picrocrocin contents. Moreover, spices produced in three different regions of the Lebanese territory have been clearly differentiated. Saffron cultivated in the Qaa region displayed a high glucose, fatty acids and polyphenols content, whereas Hermel saffron exhibited the largest rate of picrocrocin and glycosylated carotenoids. Finally, samples from Baalbeck showed lower rates for the majority of metabolites. Moreover, Lebanese saffron showed a high antioxidant activity in ABTS and DPPH assays. A low dose of saffron extract (10 µg/mL) inhibited the growth of human lung adenocarcinoma cells, probably due to the high polyphenolic content. This study highlights the quality and peculiarity of Lebanese saffron cultivated in Northern Beqaa district and allows for a good discrimination between spices produced in relatively close territory.     

Quantitation of transdermal tadalafil in human skin by reversed-phase high-performance liquid chromatography

A reliable and sensitive HPLC method was developed for the quantitation of tadalafil transdermal permeation through human skin. An RP column with UV detection at 290 nm was used for chromatographic separation at ambient temperature. The mobile phase was acetonitrile-water containing 20 mM pH 7 phosphate buffer (35/65, v/v) with a flow rate of 1.0 mL/min. The LOQ achieved was 1 ng/mL, and the calibration curve showed good linearity over the concentration range of 5-2000 ng/mL for tadalafil, with a determination coefficient (R2) of 0.998. The RSD values of intraday and interday analyses were all within 7%. Parameters of validation proved the precision of the method; this validated method was applied for the determination of tadalafil in transdermal permeation and drug deposition in human skin studies.     

Selective Homogeneous Palladium(0)-Catalyzed Hydrogenation of Alkynes to (Z)-Alkenes

Zero-valent palladium precatalysts containing rigid bidentate bis(arylimino)acenaphthene ligands (shown schematically) facilitate the highly stereoselective homogeneous catalytic hydrogenation of alkynes to (Z)-alkenes. Internal, terminal, aryl-substituted, and cyclic alkynes are suitable substrates, as are some enynes, which are chemoselectively hydrogenated to dienes. E=CO(2)Me; R(1), R(2)=4-OCH(3), 4-CH(3), 2,6-(CH(3))(2).     

A critical investigation of the effects of the radio frequency potential on the trapping of externally injected ions in ion trap mass spectrometry

The sensitivity of all ion trap mass spectrometry (ITMS) methods is dependent on the trapping efficiency of the instrument. For ITMS instruments utilizing external ion sources, such as laser desorption, trapping efficiency is known to depend on the phase and amplitude of the radio frequency (RF) potential applied to the ring electrode at the time of ion introduction. It is remarkable that, in a considerable body of literature, no consensus exists regarding the effects of these parameters on the efficacy of trapping externally generated ions. In this paper, a summary of the literature is presented in order to highlight significant discrepancies. New laser desorption ion trap mass spectrometry (LD-ITMS) data are also presented, from which conclusions are drawn in our effort to clarify some of the confusion. Copyright 1999 John Wiley & Sons, Ltd.     

Photoelastic determination of stresses in multiple-pin connectors

The design, fabrication, and testing of photoelastic models of double-lap, multiple-pin connectors are discussed. Interest is in the stresses in the inner laps. These stresses are determined by constructing models with photoelastic inner laps and transparent-acrylic outer laps. The connectors have two pins, in tandem, parallel to the load direction. A photoelastic-isotropic point is shown to permit the evaluation of load sharing between the two pins. A numerical scheme, utilizing the isochromatic- and isoclinic-photoelastic data and a finite-difference representation of the planestress equilibrium equations, is used to compute the stresses around the two pins. Representative stress distributions and stress-concentration factors are shown.     

Influence of flow on longevity of superhydrophobic coatings

Previous studies have demonstrated the capability of superhydrophobic surfaces to produce slip flow and drag reduction, which properties hold considerable promise for a broad range of applications. However, in order to implement such surfaces for practical utilizations, environmental factors such as water movement over the surface must be observed and understood. In this work, experiments were carried out to present a proof-of-concept study on the impact of flow on longevity of polystyrene fibrous coatings. The time-dependent hydrophobicity of a submerged coating in a pressure vessel was determined while exposing the coating to a rudimentary wall-jet flow. Rheological studies were also performed to determine the effect of the flow on drag reduction. The results show that the longevity of the surface deteriorates by increasing the flow rate. The flow appears to enhance the dissolution of air into water, which leads to a loss of drag reduction.     

Liposomal FRET Assay Identifies Potent Drug-Like Inhibitors of the Ceramide Transport Protein (CERT)

Ceramide transfer protein (CERT) mediates non-vesicular transfer of ceramide from endoplasmic reticulum to Golgi apparatus and thus catalyzes the rate-limiting step of sphingomyelin biosynthesis. Usually, CERT ligands are evaluated in tedious binding assays or non-homogenous transfer assays using radiolabeled ceramides. Herein, a facile and sensitive assay for CERT, based on Förster resonance energy transfer (FRET), is presented. To this end, we mixed donor and acceptor vesicles, each containing a different fluorescent ceramide species. By CERT-mediated transfer of fluorescent ceramide, a FRET system was established, which allows readout in 96-well plate format, despite the high hydrophobicity of the components. Screening of a 2 000 compound library resulted in two new potent CERT inhibitors. One is approved for use in humans and one is approved for use in animals. Evaluation of cellular activity by quantitative mass spectrometry and confocal microscopy showed inhibition of ceramide trafficking and sphingomyelin biosynthesis.     

Synthesis and antimicrobial activities evaluation of some new thiadiazinone and thiadiazepinone derivatives bearing sulfonamide moiety

A new series of novel functionalized 1,3,4-thiadiazin-5-ones and 1,3,4-thiadi-azepin-5-ones bearing sulfonamide moieties were synthesized via 1,3-dipolar cyclocondensation reaction of nitrilimines with α-mercaptoesters and mercaptosuccinic acid respectively. The structures of the prepared compounds were confirmed by spectral methods (IR, ¹H-NMR, ¹³C-NMR and MS spectroscopy) and elemental analysis. The newly synthesized compounds were screened for their in vitro antimicrobial activity. Some of titled compounds exhibited significant antimicrobial activity on several strains of microbes.     

Turbulent flow around single concentric long capsule in a pipe

A numerical solution was developed for the equations governing the turbulent flow around single concentric long capsule in a pipe. First, a turbulence model was established for the concentric annulus between the capsule and the pipe to simulate the flow as axi-symmetric, two dimensional, steady flow without edge effect. Second, the same case was considered taking into account the edge effect. Finally, turbulence modelling was established to simulate the case as a three dimensional steady flow, with a view of investigating the validity of axi-symmetric flow assumption. Three different turbulence models were used: an algebraic model (Baldwin–Lomax model) and two types of two-equation models (k–ε and k–ω). Obtained results of pressure gradient along the capsule were compared with available experimental data to verify the used models. In addition, experimental data of the velocity profiles of other investigators were also used in this concern. The results predicted by the three different turbulence models were shown to agree well with the experimental data, though precision differed from one to another.     

An analog simulation study of the rocking response of a railroad freight vehicle

The steady state response of a single large capacity railroad freight vehicle is presented. The vehicle is described through an appropriate multi-degree of freedom non-linear mathematical model. The equations of motion of the system are derived by using Lagrange's procedure. The analog computer is employed for solving the non-linear differential equations of motion for obtaining the system's rocking response in the time domain. The vehicle steady state frequency response is derived from a sequence of time responses. By utilizing the frequency response plots a complete study of the system sensitivity to variation in the suspension parameters is carried out. The study shows that a possible practical solution to the freight car rocking problem can be achieved by using additional stabilizing devices consisting of friction and viscous dampers.