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Test Solutions (test + solution)
Selected AbstractsA Novel Al(III)-Selective Electrochemical Sensor Based on N,N,-Bis(salicylidene)-1,2-phenylenediamine ComplexesELECTROANALYSIS, Issue 16 2006B. Gholivand Abstract A polyvinylchloride membrane sensor based on N,N,-bis(salecylidene)-1,2-phenylenediamine (salophen) as membrane carrier was prepared and investigated as a Al3+ -selective electrode. The sensor exhibits a Nernstian response toward Al(III) over a wide concentration range (8.0×10,7,3.0×10,2,M), with a detection limit of 6.0×10,7,M. The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 3.2,4.5. The electrode possesses advantages of very fast response and high selectivity for Al3+ in comparison with alkali, alkaline earth and some heavy metal ions. The sensor was used as an indicator electrode, in the potentiometric titration of aluminum ion and in determination of Al3+ contents in drug, water and waste water samples. [source] A Reference Electrode for Electrochemical and Cryoelectrochemical Use in Tetrahydrofuran SolventELECTROANALYSIS, Issue 21 2005Christopher Abstract We report a reference electrode for direct use in tetrahydrofuran (THF) at low temperatures. A reference solution containing equimolar amounts of ferrocene/ferrocenium hexafluorophosphate (Fc/Fc+) are prepared to give a 4,mM solution in THF that contains tetrabutylammonium hexafluorophosphate (TBAF) supporting electrolyte thus, minimizing liquid junction potentials. The reference solution is added to a sealed glass tube with a porous frit at one end, and a platinum wire is inserted into the tube. The reference electrode assembly is then inserted into a THF test solution. Potentiometric measurements show that the system responds in the expected Nernstian fashion over the concentration and temperature ranges, 4,mM to 40,,M and 20,°C to ,45,°C respectively. In addition, it is shown by steady,state cyclic voltammetry at a platinum microelectrode that the chemical reactivity of ferrocenium hexafluorophosphate (Fc+) otherwise seen in THF is suppressed by ion-pairing with PF using tetrabutylammonium hexafluorophosphate (TBAF) as the supporting electrolyte. [source] Immobilized Cytochrome c Sensor in Organic/Aqueous Media for the Characterization of Hydrophilic and Hydrophobic AntioxidantsELECTROANALYSIS, Issue 18 2003Moritz Beissenhirtz Abstract A method for the characterization of antioxidants is introduced, which allows the measurement of pure hydrophilic and hydrophobic substances as well as complex cosmetic creams. The sensor is based on cytochrome c covalently immobilized on a gold wire electrode working in mixtures of phosphate buffer and organic solvents. It is combined with a superoxide generating enzyme system. The decrease of the superoxide concentration in the test solution by the added antioxidants is detected and used for the quantification of their antioxidative efficiency. Electrochemical properties of immobilized cytochrome c, such as formal potential and heterogeneous electron transfer rate constant, have been investigated in mixtures of aqueous buffer and DMSO, methanol, butanediol, and THF. The maximum organic solvent content for quasi-reversible electrode behavior was correlated to spectroscopic measurements. The activity of the radical producing enzyme in such media was determined and the radical generation characterized. The antioxidative properties of pure substance such as ascorbic acid and Biochanin A as well as of five anti-ageing cosmetic creams were studied. This showed also the influence of matrix composition on the efficiency of antioxidative supplements. [source] Field-scale 13C-labeling of phospholipid fatty acids (PLFA) and dissolved inorganic carbon: tracing acetate assimilation and mineralization in a petroleum hydrocarbon-contaminated aquiferFEMS MICROBIOLOGY ECOLOGY, Issue 3 2002Silvina A. Pombo Abstract This study was conducted to determine the feasibility of labeling phospholipid-derived fatty acids (PLFA) of an active microbial population with a 13C-labeled organic substrate in the denitrifying zone of a petroleum hydrocarbon-contaminated aquifer during a single-well push-pull test. Anoxic test solution was prepared from 500 l of groundwater with addition of 0.5 mM Br, as a conservative tracer, 0.5 mM NO3,, and 0.25 mM [2- 13C]acetate. At 4, 23 and 46 h after injection, 1000 l of test solution/groundwater mixture were sequentially extracted. During injection and extraction phases we measured Br,, NO3, and acetate concentrations, characterized the microbial community structure by PLFA and fluorescent in situ hybridization (FISH) analyses, and determined 13C/12C ratios in dissolved inorganic carbon (DIC) and PLFA. Computed first-order rate coefficients were 0.63±0.08 day,1 for NO3, and 0.70±0.05 day,1 for acetate consumption. Significant 13C incorporation in DIC and PLFA was detected as early as 4 h after injection. At 46 h we measured ,13C values of up to 5614, in certain PLFA (especially monounsaturated fatty acids), and up to 59.8, in extracted DIC. Profiles of enriched PLFA and FISH analysis suggested the presence of active denitrifiers. Our results demonstrate the applicability of 13C labeling of PLFA and DIC in combination with FISH to link microbial structure and activities at the field scale during a push-pull test. [source] Effects of Hf content and immersion time on electrochemical behavior of biomedical Ti-22Nb- xHf alloys in 0.9% NaCl solutionMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2009B. L. Wang Abstract The aim of this study was to investigate the effects of Hf content and immersion time on the electrochemical corrosion behavior of the Ti-22Nb- xHf (x,=,0, 2, 4, and 6 at%) alloy samples in 0.9% NaCl solution at 37,°C and neutral pH range, utilizing the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. From the polarization curves, all these alloys exhibited typical passive behavior, which was indicated by a wide passive region without the breakdown of the passive films and low corrosion current densities. In addition, the values of the corrosion current densities and passive current densities decreased with increase in the Hf content. The EIS results, fitted by RS(QPRP) model, exhibited capacitive behavior (high corrosion resistance) with phase angles closed to ,80° and high impedance values at low and medium frequencies, indicating the formation of a highly stable film on these alloys in the test solution. The resistance of the passive films improved with increase in the Hf content and immersion time. All these observations suggested a more noble electrochemical behavior of the Ti-22Nb- xHf alloys compared to the Ti-Nb binary alloy. [source] Influence of testing parameters on the corrosion rate of magnesium alloysMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 6 2004M. Kühlein Abstract In sodium chloride solutions alloy composition, phases, microstructure and grain size influence the corrosion behaviour of magnesium alloys. Concentration and distribution of the critical impurities iron, nickel and copper affect the corrosion performance strongly. Salt spray tests according to ASTM B 117 or DIN 50021 are used to control quality of magnesium alloys. Results of these tests often estimate alloy subcontractors and are therefore very important to placing. Standards specify test solution, test temperature and position of specimens during test in the salt spray chamber. Standards not prescribe preparation of test specimens, exposure period, handling of the specimens after salt spray test nor the interpretation of the results. Results of salt spray tests can be only compared, provided that test conditions are exactly given. Whether the standards fulfil the above described criteria, will be shown by extensive investigations. Therefore the influence of exposure period, surface condition and microstructure was investigated. [source] Bioartificial dextran and poly[ethylene- co -(vinyl alcohol)] hybrid sponges as support for proteinsPOLYMER INTERNATIONAL, Issue 10 2005D Silvestri Abstract A biological,synthetic hybrid material was prepared as a support for proteinic molecules. To control the conformational stability and ,vitality' of the entrapped compound, an enzyme, which catalyses a chemical reaction, was chosen. The physical immobilisation of ,-amylase on a novel biological,synthetic hybrid material was realised using a synthetic (poly[ethylene- co -(vinyl alcohol)]) and a biological (dextran) component. The supports were obtained in the form of porous sponges using the phase inversion process. The kinetic parameters of enzymatic hydrolysis of soluble starch were obtained by determining the maltose (reaction product) concentration in the test solution by a spectrophotometric method. A high amount of enzyme (10 and 15 mg per g of polymer matrix) was successfully entrapped in the polymer support and a rather good enzyme activity of entrapped ,-amylase and a constant activity for repeated use, compared with native ,-amylase, were observed. The results obtained clearly indicated that the bioartificial polymer sponges, showing an immobilisation of ,-amylase with maintenance of the catalytic function of the enzyme, can be used as suitable supports for proteins. Copyright © 2005 Society of Chemical Industry [source] Kiwi fruit is a significant allergen and is associated with differing patterns of reactivity in children and adultsCLINICAL & EXPERIMENTAL ALLERGY, Issue 7 2004J. S. A. Lucas Summary Background Allergy to kiwi fruit appears increasingly common, but few studies have evaluated its clinical characteristics, or evaluated methods of investigating the allergy. Objective To characterize the clinical characteristics of kiwi fruit allergy and to study the role of double-blind placebo-controlled food challenge (DBPCFC), skin tests and specific IgE in the diagnosis of this food allergy. Methods Two-hundred and seventy-three subjects with a history suggestive of allergy to kiwi completed a questionnaire. Forty-five were investigated by DBPCFC, prick-to-prick skin testing with fresh kiwi pulp, and specific IgE measurement. Nineteen subjects were also skin tested using a commercially available solution. Results The most frequently reported symptoms were localized to the oral mucosa (65%), but severe symptoms (wheeze, cyanosis or collapse) were reported by 18% of subjects. Young children were significantly more likely than adults to react on their first known exposure (P<0.001), and to report severe symptoms (P=0.008). Twenty-four of 45 subjects (53%) had allergy confirmed by DBPCFC. Prick-to-prick skin test with fresh kiwi was positive in 93% of subjects who had allergy confirmed by DBPCFC, and also in 55% of subjects with a negative food challenge. The commercial extract was significantly less sensitive, but with fewer false-positive reactions. CAP sIgE was only positive in 54% of subjects who had a positive challenge. Conclusions Kiwi fruit should be considered a significant food allergen, capable of causing severe reactions, particularly in young children. DBPCFC confirmed allergy to kiwi fruit in 53% of the subjects tested, who had a previous history suggestive of kiwi allergy. Skin testing with fresh fruit has good sensitivity (93%), but poor specificity (45%) in this population. CAP sIgE and a commercially available skin test solution were both much less sensitive (54%; 75%) but had better specificity (90%; 67%). [source] Novel Potentiometric Sensors of Molecular Imprinted Polymers for Specific Binding of ChlormequatELECTROANALYSIS, Issue 2 2008Ayman Abstract Molecularly imprinted polymers (MIP) were used as potentiometric sensors for the selective recognition and determination of chlormequat (CMQ). They were produced after radical polymerization of 4-vinyl pyridine (4-VP) or methacrylic acid (MAA) monomers in the presence of a cross-linker. CMQ was used as template. Similar non-imprinted (NI) polymers (NIP) were produced by removing the template from reaction media. The effect of kind and amount of MIP or NIP sensors on the potentiometric behavior was investigated. Main analytical features were evaluated in steady and flow modes of operation. The sensor MIP/4-VP exhibited the best performance, presenting fast near-Nernstian response for CMQ over the concentration range 6.2×10,6,1.0×10,2,mol L,1 with detection limits of 4.1×10,6,mol L,1. The sensor was independent from the pH of test solutions in the range 5,10. Potentiometric selectivity coefficients of the proposed sensors were evaluated over several inorganic and organic cations. Results pointed out a good selectivity to CMQ. The sensor was applied to the potentiometric determination of CMQ in commercial phytopharmaceuticals and spiked water samples. Recoveries ranged 96 to 108.5%. [source] Formation of copper complexes in landfill leachate and their toxicity to zebrafish embryosENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2000Jonathon K. Fraser Abstract Toxic metal organic complexeshavenot been found in natural waters, although someorganicacids form bioavailable lipophilic and metabolite-type metal complexes. Landfill leachates usually contain organic acids and in the urban environment these leachates, when mixed with storm waters containing Cu, could be a source of toxic Cu organic complexes in streams and estuaries. We investigated the formation of Cu complexes in the leachate from an active urban landfill and found that some of the complexes formed were toxic to zebrafish embryos. High and low nominal molecular weight (NMWT) fractions; >5,000 Da and <700 Da, of leachate both formed Cu complexes with almost identical Cu complexing characteristics but the toxicity was due solely to the low NMWT complexes formed in the <700 Da fraction. Chemical equilibrium modelling with MINTEQA2 and H and Cu complex conditional association constants and ligand concentrations obtained from pH and Cu titrations with a Cu ion-selective electrode and van den Berg,Ruzic analyses of the titration data was used to calculate the copper speciation in the embryo test solutions. This calculated speciation, which was confirmed by measurements of Cu2+ in the test solutions, enabled the toxicity due to the free Cu ion and to the Cu complexes to be distinguished. [source] Tin-containing fluoride solutions as anti-erosive agents in enamel: an in vitro tin-uptake, tissue-loss, and scanning electron micrograph studyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2009Nadine Schlueter Tin-containing fluoride solutions can reduce erosive tissue loss, but the effects of the reaction between tin and enamel are still not clear. During a 10-d period, enamel specimens were cyclically demineralized (0.05 M citric acid, pH 2.3, 6 × 5 min d,1) and remineralized (between the demineralization cycles and overnight). In the negative-control group, no further treatment was performed. Three groups were treated (2 × 2 min d,1) with tin-containing fluoride solutions (400, 1,400 or 2,100 ppm Sn2+, all 1,500 ppm F,, pH 4.5). Three additional groups were treated with test solutions twice daily, but without demineralization. Tissue loss was determined profilometrically. Energy-dispersive X-ray spectroscopy was used to measure the tin content on and within three layers (10 ,m each) beneath the surface. In addition, scanning electron microscopy was conducted. All test preparations significantly reduced tissue loss. Deposition of tin on surfaces was higher without erosion than with erosion, but no incorporation of tin into enamel was found without demineralization. Under erosive conditions, both highly concentrated solutions led to the incorporation of tin up to a depth of 20 ,m; the less-concentrated solution led to small amounts of tin in the outer 10 ,m. The efficacy of tin-containing solutions seems to depend mainly on the incorporation of tin into enamel. [source] 1-D numerical modelling of shallow flows with variable horizontal densityINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2010Feifei Zhang Leighton Abstract A1-D numerical model is presented for vertically homogeneous shallow flows with variable horizontal density. The governing equations represent depth-averaged mass and momentum conservation of a liquid,species mixture, and mass conservation of the species in the horizontal direction. Here, the term ,species' refers to material transported with the liquid flow. For example, when the species is taken to be suspended sediment, the model provides an idealized simulation of hyper-concentrated sediment-laden flows. The volumetric species concentration acts as an active scalar, allowing the species dynamics to modify the flow structure. A Godunov-type finite volume scheme is implemented to solve the conservation laws written in a deviatoric, hyperbolic form. The model is verified for variable-density flows, where analytical steady-state solutions are derived. The agreement between the numerical predictions and benchmark test solutions illustrates the ability of the model to capture rapidly varying flow features over uniform and non-uniform bed topography. A parameter study examines the effects of varying the initial density and depth in different regions. Copyright © 2009 John Wiley & Sons, Ltd. [source] Prevention of enzymatic browning of apple cylinders using different solutionsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 12 2007Charles Tortoe Summary Inhibition of enzymatic browning and decay on cut surfaces of Golden Delicious apple using ascorbic acid, cysteine, sodium chloride, calcium chloride, citric acid and sodium ascorbate alone or in combinations was investigated at 4 and 10 °C for a storage period of 0, 7 and 14 days, in an attempt to find the most effective treatment. Apple segments immersed in ascorbic acid and citric acid alone showed visual traces of browning after 7 days storage at 4 °C. After 14 days storage, only ascorbic acid and ascorbic acid plus sodium chloride had moderate browning, while all other treatments were severely affected. However, at 10 °C, only ascorbic acid was effective in reducing the level of browning, although its effect was minimal after 14 days storage. Browning was more severe at 10 °C than 4 °C in all solutions. The browning measurement (a* value) became increasingly positive from 7- to 14-day storage. Microbial decay was absent in all treatments within 7 days at 4 and 10 °C. However, three test solutions showed microbial decay after 14 days storage at 10 °C in addition to the control solution, which showed decay at both 4 and 10 °C storage temperatures. [source] Effect of an enamel matrix protein derivative (Emdogain®) on ex vivo dental plaque vitalityJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2001Anton Sculean Abstract Background: A common clinical observation following surgical periodontal therapy with an enamel matrix derivative (Emdogain®) is the improved healing of the soft tissues and the limited inflammation of the operated areas. These clinical observations are empirical and difficult to explain. One of the factors influencing the early wound healing might be a potential antimicrobial effect of Emdogain®. Aim: To investigate the effect of Emdogain® on the vitality of ex vivo supragingival dental plaque and to compare this effect to that of a standard 0.2% chlorhexidine solution. Materials and Methods: 24 patients suffering from adult periodontitis were included in the study. At the beginning of the experiment, all participants were given a professional tooth cleaning. For the following 4 days, they had to refrain from any kind of oral hygiene measures. At day 5, from each of the volunteers, a voluminous plaque biofilm sample was taken with a sterile curette from the vestibular surfaces of the 1st lower molars and divided into 5 equal parts. Each part was mounted with 5 ,l of the following solutions: (1) NaCl, (2) enamel matrix derivative dissolved in water (EMD), (3) enamel matrix derivative dissolved in the vehicle (Emdogain®), (4) vehicle (propylene glycol alginate, PGA), (5) 0.2% chlorhexidine digluconate (CHX). After a reaction time of 2 min the test solutions were sucked off, and subsequently the biofilm was stained with a fluorescence dye. The vitality of the plaque flora after the treatments was evaluated under the fluorescence microscope (VF%). Results: Plaque samples treated with NaCl showed a mean vitality of 76.8±8%. The EMD, Emdogain®, PGA and CHX showed VF values of 54.4±9.2, 21.4±10.6%, 19.6±11.6% and 32.3±11.8%, respectively. Emdogain®, PGA and CHX showed statistically highly significant reductions (p<0.0001) in terms of bacteria vitality when compared to water (negative control) and EMD. Both Emdogain® and PGA were found to be statistically significantly different compared to CHX (p<0.001) (positive control). Conclusion: The results of this study indicate that Emdogain® might have an antibacterial effect on the vitality of the ex vivo supragingival dental plaque flora. Zusammenfassung Hintergrund: Eine allgemeine klinische Beobachtung nach parodontalchirurgischer Therapie mit einem Schmelzmatrixderivat (Emdogain®) ist die verbesserte Heilung des Weichgewebes und die begrenzte Entzündung des operierten Gebietes: Diese klinischen Beobachtungen sind empirisch und schwierig zu erklären. Ein Faktor, der die frühe Wundheilung beeinflusst, könnte ein potentieller antimikrobieller Effekt von Emdogain® sein. Ziel: Untersuchung des Effektes von Emdogain® auf die Vitalität von ex vivo supragingivaler dentaler Plaque und Vergleich dieses Effektes zu demjenigen einer Standard 0.2%igen Chlorhexidinlösung. Material und Methoden: 24 Patienten, die an einer Erwachsenen-Parodontitis litten, wurden in diese Studie aufgenommen. Zu Beginn der Studie wurde bei allen Teilnehmern eine professionelle Zahnreinigung durchgeführt. An den folgenden 4 Tagen wurden keine oralen Hygienemaßnahmen erlaubt. Am Tag 5 wurde von jedem Teilnehmer eine voluminöse Plaquebiofilmprobe mit einer sterilen Kürette von der vestibulären Oberfläche des ersten unteren Molaren genommen und in 5 gleiche Teile aufgeteilt. Jeder Teil wurde mit 5 ,l der folgenden Lösungen gemischt: (1) NaCl, (2) Schmelzmatrixderivat in Wasser gelöst (EMD), (3) Schmelzmatrixderivat in einem Vehikel gelöst (Emdogain®), (4) Vehikel (Propylenglycolalginat, PGA), (5) 0.2%iges Chlorhexidindiglukonat (CHX). Nach einer Reaktionszeit von 2 Minuten wurden die Testlösungen aufgesaugt und folgend der Biofilm mit Fluoreszenzfarbstoff gefärbt. Die Vitalität der Plaqueflora nach den Behandlungen wurde unter dem Vitalfluoreszenzmikroskop (VF%) evaluiert. Ergebnisse: Die Plaqueproben, die mit NaCl behandelt wurden, zeigten eine mittlere Vitalität von 76.8±8%. Das EMD, Emdogain®, PGA und CHX zeigten VF Werte von 54.4±9.2%, 21.4±10.6%, 19.6±11.6% und 32.3±11.8%. Emdogain®, PGA und CHX zeigten statistisch signifikant höhere Reduktionen (p<0.0001) in Beziehung zur bakteriellen Vitalität, wenn zu Wasser (negative Kontrolle) und EMD verglichen wurde. Sowohl Emdogain® und PGA waren statistisch signifikant unterschiedlich zu CHX (p<0.0001) (positive Kontrolle). Schlussfolgerung: Die Ergebnisse dieser Studie zeigten, dass Emdogain® einen antibakteriellen Effekt auf die Vitalität von supragingivaler dentaler ex vivo Plaqueflora haben könnte. Résumé Origine: Une observation clinique courante durant un traitement parodontal chirurgical à l'aide de protéines de la matrice améllaire (Emdogain®) est une meilleure guérison des tissus mous et une inflammation moindre. Ces observations cliniques sont empiriques et difficiles à expliquer. Un des facteurs influençant la guérison précoce peut être un effet antimicrobien de l'EMD. But: Le but de cette étude a été d'évaluer l'effet de l'Emdogain® sur la vitalité de la plaque dentaire sus-gingivale ex vivo et de comparer cet effet avec une solution de chlorhexidine 2%. Matériaux et Méthodes: 24 patients souffrant de parodontite de l'adulte ont été inclus dans cette étude. Au début de l'expérience, tous les participants ont recu un nettoyage dentaire professionnel. Pendant les 4 journées suivantes, ils ont dû arrêté toute hygiène buccale. Au jour 5, une quantité de plaque dentaire volumineuse a étééchantillonné des surfaces vestibulaires des premières molaires inférieures de chaque volontaire à l'aide d'une curette stérile et divisée en 5 parts égales. Chaque partie a été montée avec 5 ,l des solutions suivantes: (1) NaCl, (2) EMD: dérivé de la matrice améllaire dissout dans l'eau (3) Emdogain®: dérivé de la matrice améllaire dissout dans son véhicule, (4) PGA: le véhicule propylène glycol alginate, (5) CHX: chlorhexidine 0.2%. Après un temps de réaction de 2 min, les solutions tests ont été aspirées et le biofilm dentaire a été imprégné d'un colorant de fluorescence. La vitalité de la flore de la plaque dentaire après ces traitements a étéévaluée sous microscopie à fluorescence (VF%). Résultats: Les échantillons de plaque traités avec NaCl possèdaient une vitalité moyenne de 76.8±8%. L'EMD, Emdogain®, PGA, et CHX avaient des valeurs VF respectives de 54.4±9.2%, 21.4±10.6%, 19.6±11.6% et 32.3±11.8%. Emdogain®, PGA, et CHX réduisaient la vitalité bactérienne de manière très hautement significative (p<0.0001) lorsque ces solutions étaient comparées aux contrôle négatif NaCl et à EMD. Tant Emdogain® que PGa étaient différents comparés au contrôle positif CHX (p<0.001). Conclusions: Les résultats de cette étude indiquent que Emdogain® pourrait avoir un effet antibactérien sur la vitalité de la flore se trouvant dant la plaque dentaire sus-gingivale ex vivo. [source] The effect of different kinds of electrolyte and non-electrolyte solutions on the survival rate and morphology of zebrafish Danio rerio embryosJOURNAL OF FISH BIOLOGY, Issue 7 2009F. Lahnsteiner The effect of electrolyte and non-electrolyte solutions on the survival and on the morphology of zebrafish Danio rerio embryos was investigated. Embryos in different ontogenetic stages were incubated in electrolyte (NaCl, KCl, MgCl2 and CaCl2) and non-electrolyte solutions [sucrose and polyvinylalcohol (PVA)] of different concentrations for 5 , 15 min. The embryos were hatched to the long-pec stage and the effective concentrations which caused a 50% decrease in embryo development (EC50) were determined. The morphometric changes, which were caused by the test solutions, were measured. Ion channel blockers were used to see if active ion transport played a role for embryo survival. Finally, dechorionated embryos were exposed to the test solutions to get indications about the importance of chorion and perivitelline space. For 12 hours post fertilization (hpf) embryos and a 15 min exposure period, EC50 was highest for MgCl2 (1·60 mol l,1), followed by sucrose (0·73 mol l,1), NaCl (0·49 mol l,1), KCl (0·44 mol l,1), CaCl2 (0·43 mol l,1) and PVA [0·0005 mol l,1 (2·2%)]. EC50 were lower for early embryonic stages than for advanced stages for all solutions with exception of MgCl2 and sucrose. At the EC50, MgCl2 and CaCl2 solutions did not induce morphometric changes. NaCl and sucrose solutions induced reversible morphometric changes, which were compensated within 10 min. Only the EC50 of KCl and PVA solutions induced permanent morphometric changes, which could not be compensated. Incubation of embryos in electrolyte and non-electrolyte solutions together with ouabain (blocker of Na+, K+ ATPase), HgCl3 (dose-dependent inhibition of aquaporine channels), verapamil (inhibition of calcium and magnesium uptake) and amiloride (inhibition of sodium uptake) significantly decreased the per cent of embryos developing to the long-pec stage in comparison to the same solutions without blockers. Ouabain and HgCl3 also induced morphometric changes. For dechorionated embryos the survival rates in water and in the different test solutions were similar to untreated embryos. [source] ,-Monoisostearyl glyceryl ether enhances percutaneous penetration of indometacin in-vivoJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2002Atsushi Suzuki ABSTRACT Molecules that reversibly remove the barrier resistance of skin enhance penetration. ,-Monoisostearyl glyceryl ether (GE-IS) is a novel compound that can be used as a non-ionic surfactant and increases percutaneous penetration of indometacin in rat abdominal skin in-vitro. The present study investigated GE-IS-induced enhancement of indometacin penetration in-vivo. When 1% GE-IS in propylene glycol was applied to rat abdominal skin, serum and muscle concentrations of indometacin increased markedly. Anti-inflammatory activities of test solutions containing both indometacin and GE-IS were investigated in experimental models of acute and chronic inflammation. Application of indometacin with GE-IS to the skin produced greater inhibitory effects on carrageenan-induced rat paw oedema, UV-induced erythema in guinea-pigs, and adjuvant arthritis in rats, compared with application of indometacin alone. The results suggest that GE-IS enhances penetration in-vivo and improves the anti-inflammatory effects of indometacin in animal models. Thus, GE-IS might contribute to the development of cosmetic or medical formulations to improve transfer of bioactive substances to hypodermal sites. [source] Bactericidal effect of chlorine on Mycobacterium paratuberculosis in drinking waterLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2001L.B. Whan Aims:,One possible route of transmission of Mycobacterium paratuberculosis from cattle to humans is via contaminated water supplies. The aim of this work was to determine whether this organism can survive standard water treatment processes. Methods and Results:,Two strains of M. paratuberculosis (bovine strain, NCTC 8578 and human strain Linda, ATCC 43015) were subjected to various chlorine concentrations (0·5, 1·0 and 2·0 ,g ml,1) for 15 and 30 min. Chlorine test solutions were made up in two types of water, sterile water that had been deionized and subjected to reverse osmosis (DRO) and DRO water containing MgCl2, CaCl2, NaHCO3 and bovine serum albumin (0·3% w/v), the latter to mimic conditions the organism would experience in commercial water treatment operations. Conclusions:,The data showed that when initial inoculum levels were high (106 cfu ml,1) neither M. paratuberculosis strain was completely killed at the free chlorine concentrations and contact times applied. Log10 reductions in the range 1·32,2·82 were observed. The greatest log10 reduction in cell numbers (2·82 and 2·35 for the bovine and human strains, respectively) was observed at the highest chlorine concentration (2 ,g ml,1) and longest contact time (30 min). Significance and Impact of the Study:,This work highlights the need for further research into the survival of M. paratuberculosis during water treatment. [source] Effect of casein phosphopeptide-amorphous calcium phosphate added to acidic beverages on enamel erosion in vitroAUSTRALIAN DENTAL JOURNAL, Issue 3 2010DJ Manton Abstract Background:, To investigate, in vitro, the effect on enamel erosion of the addition of 0.2% w/v casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) to four commercially-available soft drinks, two of which were carbonated. Methods:, Enamel specimens (n = 27) were sectioned from sound extracted human third molar teeth and polished to a mirror finish. Exposed enamel windows of 1 mm2 were created by painting the surface with acid-resistant nail varnish. Four citric flavoured soft drinks (pH range 2.2 to 2.4) and distilled deionized water (DDW) were tested. Each drink was tested with and without 0.2% CPP-ACP w/v. The specimens were placed into 50 mL of solution at 37 °C for 30 minutes, rinsed and varnish removed. The samples were profiled with a white light profilometer and erosive depths recorded. Results:, All soft drinks tested caused enamel erosion but adding 0.2% w/v CPP-ACP significantly reduced (p <0.05) erosive depth in all test solutions in comparison with the solutions without CPP-ACP. The erosive depths for all solutions with 0.2% CPP-ACP did not differ significantly from those of DDW. Conclusions:, Adding CPP-ACP at 0.2% w/v significantly decreased the erosivity of all four soft drinks. The erosivity of the soft drinks with 0.2% CPP-ACP added did not differ significantly from that of distilled water. [source] Use of capillary electrophoresis in drug quality assessment of synthetic porcine secretinBIOMEDICAL CHROMATOGRAPHY, Issue 1 2005Baile A. Moumakwa Abstract The purity pro,le for porcine secretin attributable to contamination by equilibrium products such as aspartoyl3 secretin has been shown to be dependent on the pH of the analytical system. Capillary zone electrophoresis (CZE) methods have been developed for the ef,cient separation of synthetic porcine secretin, its equilibrium products and other impurities in aqueous solutions at both acidic and alkaline pH. These conditions are more representative of those used for the reconstitution and administration of porcine secretin, and good results cannot be achieved using HPLC due to poor peak shape above pH 5.8. The in,uence of various CZE operational parameters was systematically examined. The methods were validated for accuracy, precision, linearity, LOD and LOQ. A comparative evaluation of the stability of test solutions was determined using CZE and HPLC over a range of pH values. HPLC and CZE methods produced similar results at low pH. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||