Determination of 3-hydroxy pterocarpan, a novel osteogenic compound in rat plasma by liquid chromatography-tandem mass spectrometry: application to pharmacokinetics study

A rapid, sensitive and selective LC‐MS/MS method for the quantitative analysis of 3‐hydroxy pterocarpan (S006‐1709) in female rat plasma has been developed and validated. A Discovery RP₁₈ column was used for the chromatographic elution using acetonitrile and 0.1% acetic acid in water as mobile phase (80:20 v/v) at the flow rate of 0.5 mL/min. MS/MS analysis was performed using a triple quadrupole mass spectrometer with electrospray ionization in negative ion mode using biochanin as an internal standard (IS). Extraction of S006‐1709 and IS from rat plasma was done by liquid–liquid extraction method using diethyl ether. The LC‐MS/MS method was sensitive with 1.95 ng/mL as the limit of detection and 3.9 ng/mL as the lower limit of quantification. The method was linear in the concentration range of 3.9–1000 ng/mL. The percentage bias for intraday and interday accuracy was not greater than 4.2 and the %RSD for intraday and interday precision was not greater than 13.2. The recoveries of S006‐1709 and IS were 73.9–79.3 and 85.7%, respectively. S006‐1709 was found to be stable in various stability studies. The validated LC‐MS/MS method was successfully applied for the oral pharmacokinetics study of S006‐1709 at 10 mg/kg in female Sprague–Dawley rats. Copyright © 2010 John Wiley & Sons, Ltd.     

Intramolecular Force Fields and Vibrational Amplitudes of Disulfur Monoxide Isotopes

The force constants of S₂O have been calculated smploying GVFF and UBFF models. The reliability of the set of force constants have been examined. The mean amplitudes of vibration have also been evaluated at three temperatures, viz., 0°K, 298·15°K and 500°K. The results have been briefly discussed. The mean amplitude values will be helpful in interpretation of the electron diffraction data whenever available.     

Performance analysis of symmetrical 10 Gbps colorless WDM-PON using subcarrier modulated downstream and wavelength converted upstream through RSOA

Here we have demonstrated a novel architecture of colorless wavelength division multiplexed-passive optical network (WDM-PON) and analyze its performance which is capable of transmitting 10 Gbps data symmetrically in both downstream and upstream. In this architecture downstream data is subcarrier modulated (SCM) using radio frequency (RF) as subcarrier and laser frequency as carrier with the help of a Mach–Zehnder modulator (MZM). For upstream data modulation an electro-absorption modulator, an optical coupler and reflective semiconductor optical amplifier (RSOA) are used. Upstream data is transmitted through wavelength conversion between pump wavelength and continuous wave light sent from central office (CO) using cross gain modulation (XGM) in RSOA. Pump wavelengths have separate wavelength band than the carrier's wavelength sent from optical network unit (ONU) and can be chosen any one in its band. Since carrier reuse scheme is implemented so all the ONUs are operates in colorless mode. Effect of ER of delay interferometer (DI) on output OCSR of DI for different input OCSR is performed for SCM data. Simulation is performed with all 16 downlink and 16 uplink channels having data rate of 10 Gbps having acceptable performance.     

First Dual Responsive “Turn-On” and “Ratiometric” AIEgen Probe for Selective Detection of Hydrazine Both in Solution and the Vapour Phase

A new dual responsive “turn-on” and “ratiometric” aggregation-induced emission luminogen (AIEgen) 3-formyl-5-(piperidin-1-yl)biphenyl-4-carbonitrile 6 a (FPBC 6 a ) for selective detection of hydrazine in solution as well as in vapour phase is described. At a low concentration of 2.5 μm , the probe FPBC 6 a is non-fluorescent (turn-off) but remarkably lights up (turn-on with blue emission) in the presence of hydrazine solution (0.25–25 μm ). Interestingly, at higher concentrations, the nanoaggregates of FPBC 6 a (>25 μm , 99 % HEPES in DMSO) displayed ratiometric response in the presence of hydrazine with a remarkable hypsochromic shift from the green (500–550 nm) to blue regions (440–480 nm). Furthermore, a real application of FPBC 6 a was successfully demonstrated through the detection and visualization of hydrazine in live cervical cancer cells as well as using portable test strips.     

Entrapment of Elusive Guests within Metal‐Seamed Nanocapsules

Anions play a crucial role in locking alkali metals on the interior of metal–organic capsules that contain structural water gates. This role is further evidenced when stitching‐up the capsule seam, resulting in either expulsion or trapping of cesium ions depending on the anion employed.     

Evaluation of the Free Radical Scavenging Activities of Ellagic Acid and Ellagic Acid Peracetate by EPR Spectrometry

The purpose of this study was to examine the free radical scavenging and antioxidant activities of ellagic acid (EA) and ellagic acid peracetate (EAPA) by measuring their reactions with the radicals, 2,2-diphenyl-1-picrylhydrazyl and galvinoxyl using EPR spectroscopy. We have also evaluated the influence of EA and EAPA on the ROS production in L-6 myoblasts and rat liver microsomal lipid peroxidation catalyzed by NADPH. The results obtained clearly indicated that EA has tremendous ability to scavenge free radicals, even at concentration of 1 µM. Interestingly even in the absence of esterase, EAPA, the acetylated product of EA, was also found to be a good scavenger but at a relatively slower rate. Kinetic studies revealed that both EA and EAPA have ability to scavenge free radicals at the concentrations of 1 µM over extended periods of time. In cellular systems, EA and EAPA were found to have similar potentials for the inhibition of ROS production in L-6 myoblasts and NADPH-dependent catalyzed microsomal lipid peroxidation.     

Inter-molecular physiochemical characterization for etodolac-hydroxypropyl-β-cyclodextrin polymeric systems in solid and liquid state

The purpose of this study was to explore the utility of hydroxypropyl-β-cyclodextrin (HP-β-CD) systems in forming inclusion complexes with the anti-rheumatic or anti-arthritic drug, etodolac (EDC), in order to overcome the limitation of its poor aqueous solubility. This inclusion system achieved high solubility for the hydrophobic molecule. The physical and chemical properties of each inclusion compound were investigated. Complexes of EDC with HP-β-CD were obtained using the kneading and co-evaporation techniques. Solid state characterization of the products was carried out using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Studies in the solution state were performed using UV-Vis spectrophotometry and ¹H-NMR spectroscopy. Phase solubility profiles with HP-β-CD employed was found to be A_L type. Stability constants (K_c) from the phase solubility diagrams were calculated indicating the formation of 1:1 inclusion complex. Stability studies in the solid state and in liquid state were performed; the possible degradation by RP-HPLC was monitored. The dissolution studies revealed that EDC dissolution rate was improved by the formation of inclusion complexes.      

Chemical force titrations of functionalized Si(111) surfaces

Chemical force titrations-plots of the adhesive force between an atomic force microscope tip and sample as a function of pH-were acquired on alkyl monolayer-derivatized Si(111) surfaces. Gold-coated AFM tips modified with thioalkanoic acid self-assembled monolayers (SAM) were employed. Alkyl monolayer-derivatized Si(111) surfaces terminated with methyl, carboxyl, and amine groups were produced via hydrosilylation reactions between 1-alkene reagents and H-terminated silicon. The functionalized surfaces were characterized using standard surface science techniques (AFM, FTIR, and XPS). Titration of the methyl-terminated surface using the modified (carboxyl-terminated) atomic force microscope tip resulted in a small pH-independent hydrophobic interaction. Titration of the amine-terminated surface using the same tip resulted in the determination of a surface pKa of 5.8 for the amine from the pH value from the maximum in the force titration curve. A pK(1/2) of 4.3 was determined for the carboxyl-terminated Si(111) in a similar way. These results will be discussed in relation to the modified Si(111) surface chemistry and organic layer structure, as well as with respect to existing results on Au surfaces modified with SAMs bearing the same functional groups.     

Core-suction technique for the fabrication of optical fiber preforms

A novel technique, named "core suction," for fabricating optical fiber preforms has been devised. The technique involves drawing the molten nonconventional core glass material into the cladding tube to form the preform. The developed technique is simple, inexpensive, and shows great potential for fabricating preforms of highly nonlinear nonconventional glasses as the core material. Preforms were made with Schott SF6 and a lead-tellurium-germanate glass in silica cladding tubes, and these preforms were then pulled into fibers.