Sloshing behavior of a magnetic fluid in a cylindrical container

 Sloshing of a magnetic fluid in a laterally vibrated cylindrical container subject to a non-uniform vertical magnetic field was examined. Internal velocity profiles were measured using ultrasound Doppler velocimetry. The effect of the magnetic field on the resonant frequency of the fluid–container system was examined and the results were compared with theoretical results. The second and third peaks of the power spectra of velocity shifted to lower frequencies as the magnetic field was increased. It was observed that these derived frequency peaks were connected with swirling in the cylindrical container. Received: 9 May 2000 / Accepted: 29 May 2001 Published online: 29 November 2001     

Mecanisme de l'homologation directe d'acetyleniques en allenes

Homologation of a terminal acetylene to an allene is easily accomplished in a “one-flask” process, via a Mannich base which is transformed to the desired allene by a 1–5 hydrogen shift.     

Handiski simulator performance under PSO-based washout and control parameters optimization

Nonlinear Dynamics - The transfer of advanced technology to the person with a disability who wishes to practice a sporting activity is gaining momentum in the science/engineering world. This paper...     

Determination of paroxetine in serum treated with simple pretreatment by pre‐column high‐performance liquid chromatography using 4‐(5,6‐dimethoxy‐2‐phthalimidinyl)‐2‐methoxyphenylsulfonyl chloride as a fluorescent labeling reagent

The therapeutic drug monitoring of paroxetine could be used to optimize the pharmacological treatment of depressed patients. A simple and sensitive high‐performance liquid chromatography procedure was developed for the determination of paroxetine in serum. After simple pretreatment of serum (50 μL) with acetonitrile and o‐phthalaldehyde, paroxetine was derivatized with 4‐(5,6‐dimethoxy‐2‐phthalimidinyl)‐2‐methoxyphenylsulfonyl chloride at 70°C for 20 min in borate buffer (0.1 mol/L, pH 8.0) to produce a fluorescent product. The derivative was separated on a reversed‐phase column at 40°C for stepwise elution with (A) acetic acid (10 mmol/L) and (B) acetonitrile. The flow rate was 1.0 mL/min. The fluorescence intensity was monitored at excitation and emission wavelengths of 320 and 400 nm, respectively. The within‐day and day‐to‐day relative standard deviations were 3.0–3.4 and 2.7–8.3%, respectively. The detection limit of paroxetine was 8.3 fmol at a signal‐to‐noise ratio of 3. As the proposed method that only requires a small quantity of serum (50 μL) is simple, sensitive and reproducible, it would be useful for clinical and biochemical research as well as drug monitoring. Copyright © 2013 John Wiley & Sons, Ltd.     

Bio-Inspired Rhamnolipids,Cyclic Lipopeptides and a Chito-Oligosaccharide Confer Protection against Wheat Powdery Mildew and Inhibit Conidia Germination

Plant protection is mainly based on the application of synthetic pesticides to limit yield losses resulting from diseases. However, the use of more eco-friendly strategies for sustainable plant protection has become a necessity that could contribute to controlling pathogens through a direct antimicrobial effect and/or an induction of plant resistance. Three different families of natural or bioinspired compounds originated from bacterial or fungal strains have been evaluated to protect wheat against powdery mildew, caused by the biotrophic Blumeria graminis f.sp. tritici (Bgt). Thus, three bio-inspired mono-rhamnolipids (smRLs), three cyclic lipopeptides (CLPs, mycosubtilin (M), fengycin (F), surfactin (S)) applied individually and in mixtures (M + F and M + F + S), as well as a chitosan oligosaccharide (COS) BioA187 were tested against Bgt, in planta and in vitro. Only the three smRLs (Rh-Eth-C12, Rh-Est-C12 and Rh-Succ-C12), the two CLP mixtures and the BioA187 led to a partial protection of wheat against Bgt. The higher inhibitor effects on the germination of Bgt spores in vitro were observed from smRLs Rh-Eth-C12 and Rh-Succ-C12, mycosubtilin and the two CLP mixtures. Taking together, these results revealed that such molecules could constitute promising tools for a more eco-friendly agriculture.     

Thickening properties and emulsification mechanisms of new derivatives of polysaccharide in aqueous solution 2. The effect of the substitution ratio of hydrophobic/hydrophilic moieties

The thickening properties and association behavior of aqueous solutions of HHM-HEC (hydrophobically-hydrophilically modified hydroxyethyl cellulose) with various hydrophobic and hydrophilic substitution degrees were investigated. The HHM-HEC was used as an oil-in-water emulsifier and stable compositional regions were investigated as a function of polymer concentration and substitution degree. The viscosity of aqueous solutions of HHM-HEC increased drastically at lower concentration for HHM-HEC with a higher hydrophobic/hydrophilic substitution ratio. The intensity ratio of the first and third vibrational bands of pyrene (I(1)/I(3)) decreased with the increase of HHM-HEC concentration and the I(1)/I(3) reached a lower plateau at a lower concentration for HHM-HEC with a higher hydrophobic/hydrophilic substitution ratio. The concentration ranges of HHM-HEC solutions which stabilize O/W emulsions differ by the hydrophobic/hydrophilic substitution ratio. However the viscosity ranges of these HHM-HEC solutions were almost the same regardless of the hydrophobic/hydrophilic substitution ratio. At the suitable concentration range for emulsification, HHM-HEC networks have two properties: (1) oil particle retention capacity and (2) laxation which can trap emulsified particles.     

Synthesis and Biological Evaluation of Cassane Diterpene (5α)-Vuacapane-8(14), 9(11)-Diene and of Some Related Compounds

A set of thirteen cassane-type diterpenes was synthesized and an expedient synthetic route was used to evaluate 14-desmethyl analogs of the most active tested cassane. The anti-inflammatory activities of these 13 compounds were evaluated on a lipopolysaccharide (LPS)-activated RAW 264.7 cell line by inhibition of nitric oxide (NO) production, some of them reaching 100% NO inhibition after 72 h of treatment. The greatest anti-inflammatory effect was observed for compounds 16 and 20 with an IC_{50 NO} of 2.98 ± 0.04 μg/mL and 5.71 ± 0.14 μg/mL, respectively. Flow-cytometry analysis was used to determine the cell cycle distribution and showed that the inhibition in NO release was accompanied by a reversion of the differentiation processes. Moreover, the anti-cancer potential of these 13 compounds were evaluated in three tumor cell lines (B16-F10, HT29, and Hep G2). The strongest cytotoxic effect was achieved by salicylaldehyde 20, and pterolobirin G (6), with IC₅₀ values around 3 μg/mL in HT29 cells, with total apoptosis rates 80% at IC₈₀ concentrations, producing a significant cell-cycle arrest in the G0/G1 phase, and a possible activation of the extrinsic apoptotic pathway. Additionally, initial SAR data analysis showed that the methyl group at the C-14 positions of cassane diterpenoids is not always important for their cytotoxic and anti-inflammatory activities.     

Treatment with Glyphosate Induces Tolerance of Citrus Pathogens to Glyphosate and Fungicides but Not to 1,8-Cineole

During the postharvest period, citrus fruits are exposed to Penicillium italicum, Penicillium digitatum, and Geotrichum candidum. Pesticides such as imazalil (IMZ), thiabendazole (TBZ), orthophenylphenol (OPP), and guazatine (GUA) are commonly used as antifungals. Glyphosate (GP) is also used in citrus fields to eliminate weed growth. The sensitivity of fungal pathogens of citrus fruit to these pesticides and 1,8-cineole was evaluated, and the effect of GP on the development of cross-resistance to other chemicals was monitored over a period of 3 weeks. IMZ most effectively inhibited the mycelial growth and spore germination of P. digitatum and P. italicum, with minimum inhibitory concentrations (MICs) of 0.01 and 0.05 mg/mL, respectively, followed by 1,8-cineole, GP, and TBZ. 1,8-Cineole and GP more effectively inhibited the mycelial growth and spore germination of G. candidum, with minimum inhibitory concentrations (MICs) of 0.2 and 1.0 mg/mL, respectively, than OPP or GUA. For the spore germination assay, all substances tested showed a total inhibitory effect. Subculturing the fungal strains in culture media containing increasing concentrations of GP induced fungal tolerance to GP as well as to the fungicides. In soil, experiments confirmed that GP induced the tolerance of P. digitatum to TBZ and GP and the tolerance of P. italicum to IMZ, TBZ, and GP. However, no tolerance was recorded against 1,8-cineole. In conclusion, it can be said that 1,8-cineole may be recommended as an alternative to conventional fungicides. In addition, these results indicate that caution should be taken when using GP in citrus fields.