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Medium
Kinds of Medium Terms modified by Medium Selected AbstractsIMPROVED MEDIUM FOR DETECTION OF KLEBSIELLA IN POWDERED MILKJOURNAL OF FOOD SAFETY, Issue 1 2010HONG GAO ABSTRACT The selectivities to pathogenic Klebsiella strains of different isolation media were compared by known standard strains. The modified MacConkey-inositol-carbenicillin (MCIC) medium (Named MCIAC, MacConkey-inositol-adonitol-carbenicillin) supplemented with adonitol gave no false-negative colonies, and exhibited higher selectivity. MCIC and Simmons citrate agar with inositol (SCAI) media gave two false-negative colonies, respectively. These three media all gave two false-positive colonies, respectively. Salmonella Shigella medium gave four false-negative colonies and five false-positive colonies. Violet red bile glucose agar medium gave the most false-positive colonies, although it gave no false-negative colonies. One hundred samples of powdered milk were examined by MCIAC, MCIC and SCAI plates. The typical positive colonies were further identified using Vitek GNI Auto Microbic system and API 20E system. The results showed that the specificity of the MCIAC medium was higher than MCIC and SCAI media. PRACTICAL APPLICATIONS MacConkey-inositol-carbenicillin (MCIC) is the most commonly used selective medium for the detection of Klebsiella. But some inositol-nonfermenting Klebsiella strains would be missed when selected by this medium. We improved the MCIC medium by supplementing with 1% adonitol. The new modified medium (MacConkey-inositol-adonitol-carbenicillin, MCIAC) had advantages over other selective Klebsiella media in having a higher selectivity and an incubation time of only 16,24 h. MCIAC could be routinely used for pathogenic Klebsiella selection of powdered milk and other food samples. [source] INHIBITION OF LISTERIA INNOCUA AND L. MONOCYTOGENES IN A LABORATORY MEDIUM AND COLD-SMOKED SALMON CONTAINING LIQUID SMOKEJOURNAL OF FOOD SAFETY, Issue 2 2001SUSAN M. VITT ABSTRACT Five commercial liquid smokes were tested in vitro and the most inhibitory to Listeria monocytogenes ATCC 19115 and L. innocua ATCC 33090 was Charsol Supreme. Chum salmon samples (100-g each) were brined, dipped for 15 s at varying concentrations of liquid smoke, inoculated with L. innocua, cold-processed and analyzed. Liquid smoke concentrations of 60,100% reduced L. innocua by 3-log10/g in the final product. Dwell times of 15 s to 5 min using 60% liquid smoke gradually decreased Listeria survival with an optimum 5-min dip. Isoeugenol was antilisterial in vitro but lacked synergism with liquid smoke in cold-smoked salmon. An immunoassay kit detected low inoculum levels (< 100 CFU/g) of L. innocua in one of three samples that were treated with liquid smoke for two and four minutes. Charsol Supreme was antilisterial but could not be relied on to totally eliminate Listeria in cold-smoked salmon. Panelists found the 0 to 2-min dipped sockeye salmon slightly desirable with no significant (p < 0.05) differences. The 5-min treatment was significantly (p < 0.05) darker, scored lower in desirability and flavor and contained 93 ppm of phenolic compounds. [source] SEXING THE CANVAS: CALLING ON THE MEDIUMART HISTORY, Issue 4 2009NICHOLAS CHARE The first part of this article explores current art-historical approaches to gender through three case studies: the Venus of Willendorf; Michelangelo; and Artemisia Gentileschi. The second part employs case studies to examine how ideas about gender have historically been articulated and performed through the use of specific media and techniques. There has been little research devoted to how mediums (such as fresco, oil, and watercolour) and techniques (including drip, impasto, and staining) materialize femininity and masculinity. The article seeks to redress this neglect through an examination of some of the ways in which the gendering of materials and modes of art-making has contributed to the construction and deconstruction of sexual difference in the visual field. Artists whose works are considered include Francis Bacon, Thomas Girtin, J.M.W. Turner, and Jack Vettriano. [source] Effect of temperature and storage media on human periodontal ligament fibroblast viabilityDENTAL TRAUMATOLOGY, Issue 3 2010Beatriz Dulcineia Mendes Souza The purpose of this study was to compare the effectiveness of several storage media to preserve cultured periodontal ligament fibroblasts (PDLF) under different temperatures. The media tested were: sterile Hank's balanced salt solution (sHBSS), non-sterile HBSS (nHBSS), skimmed milk, Save-A-Tooth®, Minimum Essential Medium (MEM) and water (negative control). MEM at 37°C was used as positive control. PDLF were obtained from explants of extracted healthy human teeth. Plates containing confluent PDLF were soaked in the various media for 3, 6, 24, 48 and 72 h at 37°C and 20°C. After incubation, viability of the cells was determined using the tetrazolium salt-based colorimetric (MTT) assay and the Trypan Blue exclusion test after 6, 24, 48 and 72 h of incubation at 20°C. The results were analyzed statistically using Kruskal,Wallis, Scheffé and Mann,Whitney (, = 5%) tests. Results from the MTT assay at 37°C and 20°C showed that skimmed milk was the best storage medium for up to 24 and 48 h, respectively, followed by nHBSS and sHBSS. Results from the Trypan Blue exclusion test showed that the best storage media were milk, sHBSS and nHBSS, with no statistical differences, for any time period. The Save-A-Tooth® had a detrimental effect on cells after 24 h. The influence of temperature on the effectiveness of the storage media tested showed at 20°C a decreasing order of efficacy as follows: milk > sHBSS and nHBSS > MEM > Save-A-Tooth® > water while at 37°C it was: MEM > nHBSS > milk > sHBSS > Save-A-Tooth® > water. In conclusion, incubation temperature altered the effectiveness of the storage media and skimmed milk at 20°C was better than HBSS in maintaining PDLF viability. [source] Electrochemically-Induced Deposition of Amine-Functionalized Silica Films on Gold Electrodes and Application to Cu(II) Detection in (Hydro)Alcoholic MediumELECTROANALYSIS, Issue 19 2005Alain Walcarius Abstract Well-adherent amine-functionalized porous silica films have been deposited on gold electrodes by combining the self-assembly technology, the sol,gel process, and the electrochemical modulation of pH at the electrode/solution interface. A partial self-assembled monolayer of mercaptopropyl-trimethoxysilane (MPTMS) was first formed on disposable gold electrodes from recordable CDs (Au-CDtrodes). The so pretreated MPTMS-Au-CDtrodes were immersed in a stable sol solution (pH,3) containing (3-aminopropyl)-triethoxysilane (APTES) and tetraethoxysilane (TEOS). Polycondensation of the APTES and TEOS precursors was then achieved by applying a negative potential for a given period of time to generate a local pH increase at the electrode/solution interface and promote the deposition of the amine functionalized silica film adhering well to the electrode surface owing to the MPTMS monolayer acting somewhat as a "molecular glue". Various parameters affecting the electrodeposition process have been studied and the film permeability to redox probes in solution was characterized by cyclic voltammetry. The amine-functionalized silica film electrodes were then applied to the preconcentration of copper(II) species prior to their electrochemical detection by anodic stripping differential pulse voltammetry. Getting high sensitivity has however required the application of an electrochemical pre-activation step as the majority of the organo-functional groups were in the form of ammonium moieties (because the film was prepared from an acidic sol). This was achieved by applying a sufficiently negative potential to the electrode surface to reduce protons and increase consequently the amine-to-ammonium ratio within the film and, thus, the efficiency of the precocentration process. The resulting device was then optimized for copper(II) determination in hydroalcoholic medium, giving rise to a linear response in the 0.1,10,,M concentration range. [source] Improved ,-Glucanase Production by a Recombinant Escherichia coli Strain using Zinc-Ion Supplemented MediumENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2007U. Beshay Abstract In order to investigate the suitability of different metal chelates for affinity chromatography, an expression vector was constructed. It contained a hybrid ,-glucanase as a model protein fused with a His6 -tag and a secretion cassette providing the ability to secrete ,-glucanase into the culture medium. Supplementation of zinc to the medium led to a rapidly increased expression and release of the target protein into the cultivation medium. Results in respect to the supplementation of the commonly used Terrific Broth "TB-medium" with different metal ions are reported with special emphasis on the influence of zinc ions. A concentration of zinc ions in the order of about 0.175 mM led to optimal results. Batch cultivation under well-controlled conditions showed that the growth behavior did not change significantly by adding zinc ions. Growth in a stirred tank bioreactor was much faster in unsupplemented TB-medium compared to shake flask experiments leading to a much higher biomass concentration (15,g/L instead of 3,g/L). The secretion of ,-glucanase under theses conditions started at the transition into the stationary phase and increased to yield an extracellular activity of 1350,U/mL at the end of the fermentation process. An even higher yield of extracellular ,-glucanase (2800,U/mL) was reached when the fermentation was carried out with TB-medium supplemented with 0.175,mM ZnSO4. [source] Production of biologically active equine interleukin 12 through expression of p35, p40 and single chain IL-12 in mammalian and baculovirus expression systemsEQUINE VETERINARY JOURNAL, Issue 7 2001E. L. J. McMONAGLE Summary Interleukin-12 (IL-12) is a key cytokine in the development of cell-mediated immune responses. Bioactive IL-12 is a heterodimeric cytokine composed of disulphide linked p35 and p40 subunits. The aim of this study was to verify biologically activity of the products expressed from equine interleukin-12 (IL-12) p35 and p40 cDNAs and to establish whether equine IL-12 could be expressed as a p35/p40 fusion polypeptide, as has been reported for IL-12a of several mammalian species. We report production of equine IL-12 through expression of p35 and p40 subunits in mammalian and insect cells and of a p35:p40 fusion polypeptide in mammalian cells. Conditioned medium recovered from cultures transiently transfected with constructs encoding equine p35 and p40 subunits or single chain IL-12 enhanced IFN-, production in cells derived from equine lymph nodes. Preincubation of IFN-, inducing preparations with anti-p40 monoclonal antibody resulted in a significant decrease in IFN-, induction capacity. Medium recovered from p35 and p40-expressing baculovirus infected cultures enhanced target cell IFN-, production and proliferation. Experimental studies in mice and other animals have revealed a therapeutic benefit of IL-12 in cancer, inflammatory and infectious disease and an adjuvant effect in prophylactic regimes. Production of a bioactive species-specific IL-12 is a first step towards an investigation of its potential application in equine species. [source] From Hostage to Host: Confessions of a Spirit Medium in NigerETHOS, Issue 1-2 2002Associate Professor Adeline Masquelier Spirit possession ostensibly solves problems by freeing the object of possession from certain responsibilities, yet it also creates a whole nexus of unavoidable obligations as the human host learns to cope with the social, financial, and moral demands of her powerful alter ego. Rather than simplifying situations, possession complicates them by introducing new relations and enabling new forms of communication. In this article, I explore what bori possession as communication entailed for a young Mawri woman from Dogondoutchi (Niger) when her possessing spirit made dramatic revelations that forced her to make changes in her life. I show that possession opens up a space of self-awareness for mediums as they struggle to gain progressive control over the terms of their relationships with spirits. In this space of reflexivity they help create and in their role as interlocutors, accusers, or diviners, spirits play a crucial role in the refashioning of human histories and identities. [source] The Deterring Role of the Medium of Payment in Takeover Contests: Theory and Evidence from the UKEUROPEAN FINANCIAL MANAGEMENT, Issue 4 2000Philippe Cornu The deterring role of the medium of payment in a takeover contest is analysed from the point of view of the bidder. Cash, debt and equity are considered as alternative mediums of payment, and the bidder equilibrium strategies are specified following the Perfect Bayesian Equilibrium requirements for a signalling game. The model predicts notably that cash offers signal a high-valuing bidder, strongly determined to acquire the target firm. Moreover, cash offers deter competition better than debt or equity offers. The theoretical results are validated with data from the UK over 1995,96. [source] Fluoride-Free Hiyama and Copper- and Amine-Free Sonogashira Coupling in Air in a Mixed Aqueous Medium by a Series of PEPPSI-Themed Precatalysts,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2009Chandrakanta Dash Abstract A new series of robust, user-friendly, and highly active PEPPSI-themed (pyridine-enhanced precatalyst preparation, stabilization and initiation) (NHC)PdX2(pyridine)-type (X = Cl, Br) precatalysts of C4,C5 saturated imidazole- (1,4) and triazole-based (5 and 6) N-heterocyclic carbenes for the Hiyama and Sonogashira couplings under amenable conditions are reported. Specifically 1,6 efficiently catalyze the fluoride-free Hiyama coupling of aryl halides with PhSi(OMe)3 and CH2=CHSi(OMe)3 in air in the presence of NaOH as a base in a mixed aqueous medium (dioxane/H2O, 2:1 v/v). Along the same lines, these 1,6 precatalysts also promote the Cu-free and amine-free Sonogashira coupling of aryl bromides and iodides with phenylacetylene in air and in a mixed aqueous medium (DMF/H2O, 3/1 v/v). The complexes 1,6 were synthesized by the direct reaction of the respective imidazolinium and triazolium halide salts with PdCl2 in pyridine in the presence of K2CO3 as a base. DFT studies on the catalytically relevant palladium(0) (NHC)Pd(pyridine) precursors 1a,6a reveal significant donation from the N-heterocyclic carbene lone pair onto the unfilled ,* orbital of the trans Pd,pyridine bond. This weakens the Pd-bound "throwaway" pyridine ligand, and its dissociation marks the initiation of the catalytic cycle.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Self-Assembled Two-Dimensional Water-Soluble Dipicolinate Cu/Na Coordination Polymer: Structural Features and Catalytic Activity for the Mild Peroxidative Oxidation of Cycloalkanes in Acid-Free MediumEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2008Marina V. Kirillova Abstract The new water-soluble 2D Cu/Na coordination polymer [Cu(,-dipic)2{Na2(,-H2O)4}]n·2nH2O (1) has been synthesized by self-assembly in aqueous medium from copper(II) nitrate, dipicolinic acid (H2dipic) and sodium hydroxide in the presence of triethanolamine. It has been characterized by IR spectroscopy, FAB+ -MS, elemental and single-crystal X-ray diffraction analyses, the latter featuring a layered 2D metal,organic structure that is extended to a 3D supramolecular assembly by extensive hydrogen bonding between adjacent layers and involving crystallization water molecules. Compound 1 has been shown to act as a catalyst precursor for the peroxidative oxidation of cyclohexane and cyclopentane to the corresponding cyclic ketones and alcohols by aqueous H2O2 in MeCN solution and in the absence of acid additives.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Enantioselective One-Pot Two-Step Synthesis of Hydrophobic Allylic Alcohols in Aqueous Medium through the Combination of a Wittig Reaction and an Enzymatic Ketone ReductionEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 31 2007Marina Kraußer Abstract A one-pot two-step process for the enantioselective synthesis of hydrophobic allylic alcohols was developed, which comprises ketone formation by the Wittig reaction and their enzymatic in situ biotransformation into the desired target products. By means of this combined Wittig reaction and bioreduction, the allylic alcohols were prepared with conversions of up to 90,%, and with excellent enantioselectivities of >99,% ee. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Facile Synthesis of Flexible Bis(pyrazol-1-yl)alkane and Related Ligands in a Superbasic MediumEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 30 2007Andrei S. Potapov Abstract Flexible ligands 1,3-bis(pyrazol-1-yl)propanes, bis[2-(pyrazol-1-yl)ethyl] ethers, and bis[2-(3,5-dimethylpyrazol-1-yl)ethyl]amine were prepared by a facile procedure involving the reaction of pyrazoles with 1,3-dibromopropane, bis(2-chloroethyl) ether or bis(2-chloroethyl)amine hydrochloride in a superbasic medium (dimethyl sulfoxide/potassium hydroxide). Reaction of bis(2-chloroethyl)amine and pyrazole unexpectedly led to 1,4-bis[2-(pyrazol-1-yl)ethyl]piperazine. The corresponding 4,4,-diiodo-substituted bis(pyrazole) derivatives were prepared by oxidative iodination with I2/HIO3/H2SO4 in acetic acid. Vilsmeier,Haak formylation of some of the prepared compounds yielded the corresponding dialdehydes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Surface nucleolin participates in both the binding and endocytosis of lactoferrin in target cellsFEBS JOURNAL, Issue 2 2004Dominique Legrand Lactoferrin (Lf), a multifunctional molecule present in mammalian secretions and blood, plays important roles in host defense and cancer. Indeed, Lf has been reported to inhibit the proliferation of cancerous mammary gland epithelial cells and manifest a potent antiviral activity against human immunodeficiency virus and human cytomegalovirus. The Lf-binding sites on the cell surface appear to be proteoglycans and other as yet undefined protein(s). Here, we isolated a Lf-binding 105 kDa molecular mass protein from cell extracts and identified it as human nucleolin. Medium,affinity interactions (, 240 nm) between Lf and purified nucleolin were further illustrated by surface plasmon resonance assays. The interaction of Lf with the cell surface-expressed nucleolin was then demonstrated through competitive binding studies between Lf and the anti-human immunodeficiency virus pseudopeptide, HB-19, which binds specifically surface-expressed nucleolin independently of proteoglycans. Interestingly, binding competition studies between HB-19 and various Lf derivatives in proteoglycan-deficient hamster cells suggested that the nucleolin-binding site is located in both the N- and C-terminal lobes of Lf, whereas the basic N-terminal region is dispensable. On intact cells, Lf co-localizes with surface nucleolin and together they become internalized through vesicles of the recycling/degradation pathway by an active process. Morever, a small proportion of Lf appears to translocate in the nucleus of cells. Finally, the observations that endocytosis of Lf is inhibited by the HB-19 pseudopeptide, and the lack of Lf endocytosis in proteoglycan-deficient cells despite Lf binding, point out that both nucleolin and proteoglycans are implicated in the mechanism of Lf endocytosis. [source] Business Optimism for Small, Medium and Large Firms: Does It Explain Investment?,FISCAL STUDIES, Issue 2 2007Ciaran Driver We use UK survey data on variation in business optimism by manufacturing size group to estimate the determinants of optimism using OLS and SURE. There are similarities across the size groups but also some differences: the medium-size group seems to have been unusually affected by real interest rates in recent years. We also model investment authorisations, conditional on business optimism. Again, there are similarities across the size groups. However, the largest-size group, and possibly also the medium-size group, seem to be investing less in recent years in relation to reported optimism. By contrast, capital investment by smaller-sized firms has been stable in relation to business optimism. Some tentative explanations for these findings are explored. [source] Effects of some bacteria (Pseudomonas spp. and Erwinia herbicola) on in vitro growth of Piptoporus betulinusFOREST PATHOLOGY, Issue 6 2000K. Przyby Summary Bacteria including Pseudomonas putida, Pseudomonas fluorescens biovar I, Pseudomonas fluorescens biovar V, Pseudomonas aureofaciens and Erwinia herbicola were isolated from discoloured zones in birch trunks. Antagonistic effects of these bacteria to growth of Piptoporus betulinus mycelium were tested in vitro, both in dual culture and using bacterial cell-free culture filtrates. In dual cultures, P. putida was most effective at inhibiting mycelial growth of Piptoporus betulinus. Filtrates of P. putida inhibited growth of P. betulinus mycelium irrespective of filtrate concentration, incubation time of bacteria and timing of recording mycelium growth. The strongest antagonistic effect (inhibition of fungal growth) was observed on a medium containing 80% of sterile filtrate obtained from 15-day-old bacterial cultures. The highest stimulating effect on mycelium growth was noted on medium containing 80% filtrate obtained from 7-day-old E. herbicola cultures. Résumé Des bactéries, Pseudomonas putida, Pseudomonas fluorescens biovar I, Pseudomonas fluorescens biovar V, Pseudomonas aureofaciens et Erwinia herbicola, ont été isolées de zones colorées de troncs de bouleau. Les effets antagonistes de ces bactéries sur la croissance mycélienne de Piptoporus betulinus ont étéévalués in vitro, en cultures doubles et à partir de filtrats bactériens. En cultures doubles, P. putida a été le plus inhibiteur de la croissance du P. betulinus. Les filtrats de P. putida inhibaient la croissance quel que soit la concentration du filtrat, la durée d'incubation de la bactérie, et le délai dans lequel la croissance mycélienne était mesurée. L'effet inhibiteur le plus fort a été observé sur un milieu contenant 80% de filtrat stérile obtenu de cultures bactériennes de 15 jours. L'effet stimulant le plus fort a été noté sur un milieu contenant 80% d'un filtrat obtenu de cultures de 7 jours de E. herbicola. Zusammenfassung Verschiedene Bakterienarten (Pseudomonas putida, Pseudomonas fluorescens Biovar I, Pseudomonas fluorescens Biovar V, Pseudomonas aureofaciens und E. herbicola) wurden aus verfärbtem Holz in Birkenstämmen isoliert. Antagonistische Effekte dieser Bakterien gegenüber Myzel von Piptoporus betulinus wurden in vitroüberprüft (Dualkulturen und bakterienzellfreie Kulturfiltrate). In Dualkulturen zeigte P. putida den stärksten Hemmeffekt auf das Myzelwachstum von P. betulinus. Filtrate von P. putida hemmten das Wachstum von P. betulinus, unabhängig von der Filtratkonzentration, der Inkubationszeit der Bakterien und dem Zeitpunkt der Messung des Myzelwachstums. Der antagonistische Effekt (Hemmung des Myzelwachstums) war am ausgeprägtesten auf einem Medium, das 80% Sterilfiltrat von 15 Tage alten Bakterienkulturen enthielt. Der stärkste Stimulationseffekt auf das Myzelwachstum wurde auf einem Medium beobachtet, welches 80% Filtrat von sieben Tage alten E. herbicola -Kulturen enthielt. [source] The Nanocrystalline Nickel with Catalytic Properties on Methanol Oxidation in Alkaline MediumFUEL CELLS, Issue 5 2009R. M. A. Tehrani Abstract The hexagonal closed packed (hcp) nanocrystalline nickel (Ni), with an average diameter of 9.7,±,2.27,nm was deposited uniformly on composite graphite (CG) by the rapid scanning (6,500,mVs,1) voltammetry technique. The hcp-nano Ni-modified CG electrode was investigated for the catalytic oxidation of methanol in alkaline medium through the formation of NiOOH. A high anodic current was obtained at peak potential of +570,mV vs Ag/AgCl. Both the scan rate and the methanol concentration affected the oxidation of methanol. The results showed that catalytic activity had increased with decrease in Ni particle diameter. It was also shown that the hcp-nano Ni/CG modified electrode was the most efficient catalyst in the oxidation of methanol. [source] Special Issue of Fuel Cells , from Fundamentals to Systems devoted to selected papers presented at the international conference on Progress in MEA Components for Medium and High Temperature Polymer Electrolyte Fuel CellsFUEL CELLS, Issue 4 2009D. Jones No abstract is available for this article. [source] N,N -Dimethylformamide as a Reaction Medium for Metal Nanoparticle SynthesisADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Isabel Pastoriza-Santos Abstract The versatility of wet chemical methods has rendered them extremely popular for the preparation of metal nanoparticles with tailored size and shape. This Feature Article reviews the use of N,N -dimethylformamide (DMF) for the reduction of metal salts, mainly Au and Ag, while also acting as a solvent. Apart from describing the ability of DMF to reduce metal salts, the effect of different parameters, such as the concentration of capping agent and metal precursors, the presence of preformed seeds acting as catalysts or their crystalline structure, on particle morphology are analyzed. Published reports on the use of different capping agents are summarized, with particular emphasis on the role of poly(vinylpyrrolidone) to determine the morphology of the particles. Finally, a brief overview is provided on the modulation of the optical response in DMF-based metal nanoparticle colloids with tunable size and shape. [source] Stochastic Study of Solute Transport in a Nonstationary MediumGROUND WATER, Issue 2 2006Bill X. Hu A Lagrangian stochastic approach is applied to develop a method of moment for solute transport in a physically and chemically nonstationary medium. Stochastic governing equations for mean solute flux and solute covariance are analytically obtained in the first-order accuracy of log conductivity and/or chemical sorption variances and solved numerically using the finite-difference method. The developed method, the numerical method of moments (NMM), is used to predict radionuclide solute transport processes in the saturated zone below the Yucca Mountain project area. The mean, variance, and upper bound of the radionuclide mass flux through a control plane 5 km downstream of the footprint of the repository are calculated. According to their chemical sorption capacities, the various radionuclear chemicals are grouped as nonreactive, weakly sorbing, and strongly sorbing chemicals. The NMM method is used to study their transport processes and influence factors. To verify the method of moments, a Monte Carlo simulation is conducted for nonreactive chemical transport. Results indicate the results from the two methods are consistent, but the NMM method is computationally more efficient than the Monte Carlo method. This study adds to the ongoing debate in the literature on the effect of heterogeneity on solute transport prediction, especially on prediction uncertainty, by showing that the standard derivation of solute flux is larger than the mean solute flux even when the hydraulic conductivity within each geological layer is mild. This study provides a method that may become an efficient calculation tool for many environmental projects. [source] Methodology and Transport Medium for Collection of Helicobacter pylori on a String Test in Remote LocationsHELICOBACTER, Issue 6 2005Helen M. Windsor ABSTRACT Background.,Helicobacter pylori can be isolated from patients using the string test but contaminating oral and nasopharyngeal microflora need to be suppressed by rapid plating out onto selective culture media. Recently, use of this diagnostic method was enhanced by using a novel transport medium to collect specimens from subjects in a remote Australian clinic over 1300 km from the laboratory. Methods., Retrieved string tests were transported to the laboratory in chilled polystyrene boxes in 5 ml screw-cap bottles with 3 ml of a brain heart infusion broth plus antibiotics. These were 20 g/ml vancomycin, 10 g/ml trimethoprim, 10 g/ml cefsulodin, and 10 g/ml amphotericin B. A comparison was made between subjects who gargled with a chlorhexidine mouthwash before swallowing the string test and those who did not. Results., Forty-five urea breath test-positive subjects were tested and H. pylori was isolated from 34 of them. Successful culture was achieved from string tests that were in transit for up to 29 hours and where the maximum temperature in the transport box was 14 °C. The additional use of a mouthwash had a marked effect on the isolation rate. H. pylori was cultured from 75% of subjects who gargled but only from 39% who did not. Conclusions., This methodology and transport medium can broaden the use of the string test to more remote geographic areas where endoscopy is not feasible so that H. pylori isolates may still be obtained for diagnostic and epidemiologic studies. The value of this promising methodology of collection and transport should be assessed in a controlled study. [source] Effect of pentoxifylline on motility and membrane integrity of cryopreserved human spermatozoaINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2002P. Stanic The purpose of this study was to examine the effects of pentoxifylline used before and after semen cryopreservation,thawing on sperm motility and membrane integrity. Twenty-four semen samples were split into four equal aliquots. Aliquots were incubated at 37 °C for 30 min, followed by cryopreservation with TEST-yolk freezing medium using slow programmable freezing protocol. After 2 weeks the sperm samples were thawed, washed twice in Quinn's Sperm Washing Medium (modified HTF with 5.0 mg/mL Human Albumin) and incubated at 37 °C for 30 min. Aliquots were treated by adding 3 mmol/L pentoxifylline to: (1) fresh sperm samples during incubation period prior to cryopreservation, (2) sperm samples as a supplement to the cryoprotectant prior to cryopreservation, and (3) thawed sperm samples during incubation period. One aliquot received no treatment (control group). The addition of 3 mmol/L pentoxifylline to fresh semen during incubation period prior to cryopreservation significantly decreased progressive and total motility compared with controls. However, the addition of 3 mmol/L pentoxifylline to cryopreserved semen after thawing significantly increased progressive and total motility compared with controls. After post-thaw, no differences in motion characteristics between sperm samples treated by adding 3 mmol/L pentoxifylline as a supplement to the cryoprotectant and control groups were observed. Post-thaw hypoosmotic swelling (HOS) test scores did not improve with the addition of pentoxifylline compared with the control group. It is concluded that pentoxifylline enhanced post-thaw motility of cryopreserved human spermatozoa when added after thawing. No improvement was found by freezing sperm with pentoxifylline. [source] Influence of nutrients on proteinase A activity in draft beer during fermentationINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2010Xin Hao Summary With the increase of ,-amino nitrogen concentrations from 90 to 230 mg L,1, proteinase A (PrA) in wort fermentations was showing a downward trend while higher alcohols contents a U-shaped one. The level of 210 mg L,1 of ,-amino nitrogen supplement, at which wort fermentation exhibited a low PrA activity and a level of higher alcohols below the industrial norm (90 mg L,1), was used as the optimised ,-amino nitrogen concentration for further exploring the effect of biotin levels on PrA activity. In the biotin range of 0,65 ,g L,1, PrA activity registered the lowest value when biotin level was at 50 ,g L,1. Medium with 210 mg L,1 of ,-amino nitrogen and 50 ,g L,1 of biotin was therefore adopted for investigating influences of inorganic salt Fe2(SO4)3, KH2PO4, ZnSO4 and MgSO4 on PrA production. It was shown that Fe2(SO4)3 and KH2PO4 had significant influence on PrA production while ZnSO4 and MgSO4 did not. Based on above findings, an optimised set of nutritive elements was determined and used in fermentation. The results indicated that the activity of PrA reduced by 60% without noticeably effects of the fermentation performance and beer flavour. [source] A Tripodal Peptidic Titanium Phosphonate as a Homochiral Porous Solid Medium for the Heterogeneous Enantioselective Hydration of EpoxidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Anat Milo Abstract A porous, homochiral titanium-phosphonate material based on a tripodal peptide scaffold was used as a heterogeneous reaction medium for the enantioselective hydration (>99%) of styrene oxide. This titanium-phosphonate material, which was shown to contain confined chiral spaces, was prepared by polymerization of L -leucine onto a tris(2-aminoethyl)amine initiator, followed by capping with phosphonate groups and completed by non-aqueous condensation with titanium isopropoxide. Circular dichroism confirmed that the peptide tethers yielded a secondary structure. X-ray powder diffraction and transmission electron microscopy supported by a semi-empirical model showed the likely formation of a porous, lamellar material that was quantified by nitrogen adsorption. [source] Metal-Free and Copper-Promoted Single-Pot Hydrocarboxylation of Cycloalkanes to Carboxylic Acids in Aqueous MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Marina Abstract A simple and effective method for the transformation, under mild conditions and in aqueous medium, of various cycloalkanes (cyclopentane, cyclohexane, methylcyclohexane, cis - and trans -1,2-dimethylcyclohexane, cycloheptane, cyclooctane and adamantane) into the corresponding cycloalkanecarboxylic acids bearing one more carbon atom, is achieved. This method is characterized by a single-pot, low-temperature hydrocarboxylation reaction of the cycloalkane with carbon monoxide, water and potassium peroxodisulfate in water/acetonitrile medium, proceeding either in the absence or in the presence of a metal promoter. The influence of various reaction parameters, such as type and amount of metal promoter, solvent composition, temperature, time, carbon monoxide pressure, oxidant and cycloalkane, is investigated, leading to an optimization of the cyclohexane and cyclopentane carboxylations. The highest efficiency is observed in the systems promoted by a tetracopper(II) triethanolaminate-derived complex, which also shows different bond and stereoselectivity parameters (compared to the metal-free systems) in the carboxylations of methylcyclohexane and stereoisomeric 1,2-dimethylcyclohexanes. A free radical mechanism is proposed for the carboxylation of cyclohexane as a model substrate, involving the formation of an acyl radical, its oxidation and consequent hydroxylation by water. Relevant features of the present hydrocarboxylation method, besides the operation in aqueous medium, include the exceptional metal-free and acid-solvent-free reaction conditions, a rare hydroxylating role of water, substrate versatility, low temperatures (ca. 50,°C) and a rather high efficiency (up to 72% carboxylic acid yields based on cycloalkane). [source] Promiscuous Zinc-Dependent Acylase-Mediated One-Pot Synthesis of Monosaccharide-Containing Pyrimidine Derivatives in Organic MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Qi Wu Abstract A facile one-pot synthesis route to monosaccharide-containing pyrimidine derivatives was developed by combining the two types of catalytic activities of one enzyme in an organic medium, i.e., the Michael addition/acylation activities of zinc-dependent D -aminoacylase (DA) from Escherichia coli. First, the stepwise approach was investigated. DA showed higher activity towards the Michael addition than acylation in this reaction system. The enzymatic Michael additions of pyrimidines to vinyl acrylate proceeded very rapidly and the initial reaction rates for the Michael addition of pyrimidines to vinyl acrylate were 7.2,16.5,mM,min,1. The catalytic specificity of aminoacylases toward Michael addition was demonstrated by the combination of different control experiments. Then, the two steps could be performed in one pot and a single aminoacylase catalyzed one-pot biotransformation was constructed. Using this strategy, a series of saccharide-pyrimidine complexes with potentially biological and pharmacological applications was prepared efficiently. This high Michael addition activity of zinc-dependent aminoacylases and the novel single aminoacylase-catalyzed one-pot synthesis combining two catalytic activities in vitro is of practical significance in expanding the application of enzymes and in the evolution of new biocatalysts. [source] Highly Enantioselective Organocatalytic syn - and anti -Aldol Reactions in Aqueous MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Monika Raj Abstract We have synthesized chiral diamines that efficiently catalyze the syn - and anti -aldol reactions in aqueous medium with high diastereo- and enantioselectivities. The product, thus obtained, was further reduced selectively to give syn -configured 1,2,3-triol, an important subunit present in various monosaccharides and natural products such as (+)-boronolide. [source] Ionic Liquid (IL) as an Effective Medium for the Highly Efficient Hydroacylation Reaction of Aldehydes with AzodicarboxylatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2009Bukuo Ni Abstract The highly efficient hydroacylation reaction of aldehydes with azodicarboxylates has been carried out in the ionic liquid,1- n -butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [BMIM] [NTf2]. The products were readily separated by extraction from the reaction medium and the ionic liquid could be recycled up to 8 times and the yields of the reactions were not affected. Compared to conventional solvents, high yields were achieved with aliphatic saturated aldehydes, and the reaction can be conducted under normal to mild conditions without the use of a catalyst. [source] New Simple Hydrophobic Proline Derivatives as Highly Active and Stereoselective Catalysts for the Direct Asymmetric Aldol Reaction in Aqueous MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2008Francesco Giacalone Abstract New 4-substituted acyloxyproline derivatives with different hydrophobic properties of the acyl group were easily synthesized and used as catalysts in the direct asymmetric aldol reaction between cyclic ketones (cyclohexanone and cyclopentanone) and several substituted benzaldehydes. Reactions were carried out using water, this being the best reaction medium examined. Screening of these catalysts showed that compounds bearing the most hydrophobic acyl chains [4-phenylbutanoate and 4-(pyren-1-yl)butanoate] provided better results. The latter catalysts were successfully used in only 2 mol% at room temperature without additives to give aldol products in excellent stereoselectivities. These results demonstrate that derivatization of the proline moiety with the proper simple hydrophobic substituent in the 4-position can furnish highly active and stereoselective catalysts without the need of additional chiral backbones in the molecule. Finally, an explanation of the observed stereoselectivities in the presence of water is provided. [source] Enantioselective Michael Addition of Dicyanoolefins to ,,,-Unsaturated Aldehydes in Aqueous MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2008Jun Lu Abstract A pool of water-compatible catalysts, namely dialkyl-(S)-prolinols, has been developed for the enantioselective direct vinylogous Michael addition reaction of vinylmalononitriles to ,,,-unsaturated aldehydes in aqueous medium. In many cases, the products can be obtained in almost optically pure form (>96% ee) after a single recrystallization. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||