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Concentration Increasing (concentration + increasing)
Selected AbstractsHigh-sensitive neural network ammonia sensor based on shear horizontal surface acoustic wave devicesJOURNAL OF CHEMOMETRICS, Issue 10 2008Chi-Yen Shen Abstract In this paper, a shear horizontal surface acoustic wave devices coated with L-glutamic acid hydrochloride were applied as ammonia sensors. This sensor has shown high sensitivity and fast responses to ppb-level ammonia. The frequency shift linearly increased as the ammonia concentration increased from 40 to 400,ppb in dry environment. In the humid environment, the frequency shift gradually decreased with ammonia concentration increasing. In order to precisely estimate the ammonia in humid environment, two different neural models, the conventional feedforward neural network and quantum neural network, were used as the identifier and their performances were reported and compared. Copyright © 2008 John Wiley & Sons, Ltd. [source] Spectroscopic studies on origination of the peak at 730 nm in delayed fluorescence of chloroplastsLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2007Lizhang Zeng Abstract The origination of the peak at 730 nm in the delayed fluorescence (DF) spectrum of chloroplasts was studied using various optical analysis methods. The DF spectrum showed that the main emission peak was at about 685 nm, with a small shoulder at 730 nm when the chloroplast concentration was < 7.8 µg/mL. The intensity of the peak at 685 nm decreased, while the intensity of the peak at 730 nm increased, when the chloroplast concentrations were increased from 7.8 to 31.2 µg/mL. With the concentration increasing, the peak at 730 nm became dominant while the peak at 685 nm finally disappeared. The DF decay kinetic curves showed that the intensity of the peak at 730 nm decayed as the same speed as the intensity of the peak at 685 nm during the entire relaxation process (0.5,30.5 s). With the excitation wavelength at 685 nm, the emission intensity was stronger in the excitation spectrum at 730 nm. The absorption spectrum demonstrated that the ratio A685:A730 remained almost constant when the chloroplast concentration increased. The results suggest that the peak at 730 nm appearing in DF is mainly contributed by the fluorescence of photosystem I (PSI), generated by the re-absorption of 685 nm band DF. Copyright © 2007 John Wiley & Sons, Ltd. [source] In vivo pharmacokinetics of ketoprofen after patch application in the Mexican hairless pigBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 4 2009Masafumi Horie Abstract To evaluate the pharmacokinetics of topical drugs, in vitro permeation studies are performed using sacrificed pig skin or human tissues resected at surgery; however, these methods have their limitations in in vivo pharmacokinetics. This study examined the usefulness of Mexican hairless pigs for in vivo pharmacokinetic study, especially the drug concentration in the tissues. A ketoprofen patch was applied on the back of Mexican hairless pigs for 24,h, followed by sequential collection of blood specimens from 0 to 36,h (n=3). Also, the skin, subcutaneous fat, fascia and muscle from the center of the site of application were excised at 12,h after the application (n=4). Ketoprofen was first detected in the plasma at 8,h, the concentration increasing up to 24,h; the plasma concentration began to decrease after the removal of the ketoprofen patch. Ketoprofen concentrations in the tissues decreased with increasing depth of the tissues, but the values in the deep muscles, being the lowest among the tissues examined, were still higher than those in the plasma. While the data of drug concentration in human tissue are difficult to test, the Mexican hairless pig model appears to be attractive for in vivo pharmacokinetic studies of topically applied ketoprofen. Copyright © 2009 John Wiley & Sons, Ltd. [source] Experimental Study on the Molecular Dimension and Configuration of Polymer and Its Flow Characteristics from Electrolyte EffectCHINESE JOURNAL OF CHEMISTRY, Issue 4 2009Xiangguo LU Abstract Molecular clew dimension and configuration of polymer, and flow characteristics of polymer solution were studied from electrolyte effect, by making use of dynamic light scattering (DLS), scanning electron microscopy (SEM), apparent viscosity method and core flow experiment. It can be observed that with the electrolyte concentration increasing, there exists a variation trend of "decreasing, increasing and decreasing again" to the molecular clew dimension of the polymer. The compression action of Ca2+ or Mg2+ to the double electrode layer of polymer molecules is more powerful by comparison against Na+, which results in that Ca2+ and Mg2+ have a more extensive effect on the viscosity of polymer solution, and clew dimensions and their distribution. With the electrolyte concentration increasing, the polymer molecular configuration of multi-layer stereoscopic random reticulation transformed into a dendritic one. During the succeeding water flooding, the variation degree of injection pressure of core was mainly determined by the swelling extent of molecular clew of retained polymer and the produced amount of polymer. And the bigger the molecular weight of polymer is, the stronger the compression or swelling action of electrolyte to the molecule clews is, and the greater the increasing degree of injection pressure during succeeding water flooding is. The greater difference of electrolyte concentrations in used water between polymer flooding and succeeding water flooding can result in greater increasing degree of injection pressure during the succeeding water flooding. So, an advisable increasing in difference of electrolyte concentrations in used water between the polymer flooding and succeeding water flooding was proposed when designing the polymer flooding performance in oilfields, which has promising result for improving effect of polymer flooding. [source] | ||||||||||