Home About us Contact
|
Home About us Contact | ||
|
|
||
Various Conditions (various + condition)
Selected AbstractsEVALUATION OF SURVIVAL PATTERNS AND CELLULAR INJURY OF PSEUDOMONAS AERUGINOSA IN DIFFERENT BOTTLED WATERS STORED UNDER VARIOUS CONDITIONSJOURNAL OF FOOD SAFETY, Issue 3 2001PAULA TEIXEIRA ABSTRACT Pseudomonas aeruginosa cells were inoculated into different waters and sampled after different periods of starvation in order to evaluate the influences of storage under daylight or dark conditions, the presence or absence of the autochthonous flora, the chemical composition of the water and the storage temperature, on survival Survival was investigated by plate counts on selective and nonselective agar media. Light, low temperature (4C) and presence of the autochthonous flora negatively influenced the survival of P. aeruginosa during starvation in water. Higher survival rates were observed in waters with high mineral content. During starvation, cells developed sensitivity to the selective medium demonstrating that research is needed in the development of new media, or improvement in the existing ones, for the enumeration of P. aeruginosa in water. Current selective media/methodologies for detecting P. aeruginosa in mineral waters may seriously underestimate the levels of or presence of this organism which might represent, in some cases, a hazard to the public health. [source] The Study of Cyclization of N-Acylphenacyl Anthranilates with Ammonium Salts under Various Conditions.CHEMINFORM, Issue 30 2007Pavel Hradil Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] C(10),C(19) Bond Cleavage Reaction of 19-Oxygenated Androst-4-ene-3,6-dione Steroids under Various Conditions.CHEMINFORM, Issue 3 2005Masao Nagaoka Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis of New ,-(Polyfluoroalkyl)-,-hydroxy-,-amino AcidsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2009Nataliya A. Tolmacheva Abstract New ,-(polyfluoroalkyl)-,-hydroxy-,-amino acids were synthesized from the corresponding starting 3-(benzoylamino)-6-(polyfluoroalkyl)-2H -pyran-2-ones. The key step of the synthesis was the hydrogenation of the pyrone ring. Stereoselectivity and yields depended dramatically on the reaction conditions and the nature of the polyfluoroalkyl group. Various conditions were used for the preparation of both mixtures of diastereomers and pure diastereomers of the target amino acids. The obtained ,-(polyfluoroalkyl)-,-hydroxy-,-amino acids are of interest as analogues of 2-amino-5-hydroxyvaleric acid and glutamic acid.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Photodegradation study of a new activator of the cystic fibrosis chloride channel, the 6-hydroxy-10-chlorobenzo[c]quinolizinium chloride (MPB-07)JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2002Jean-Christophe Olivier Abstract The photodegradation of 6-hydroxy-10-chlorobenzo[c]quinolizinium chloride (MPB-07), a new activator of the transmembrane conductance regulator chloride channel, was studied in aqueous solutions exposed to artificial daylight (2300 Lux intensity). Various conditions of pH, concentration, and temperature were used. MPB-07 concentration was determined at regular time intervals by reversed-phase HPLC. MPB-07 stability was also studied at pH 7.4 in the dark. Results showed that in all the conditions tested MPB-07 underwent rapid photodegradation, apparently following first-order kinetics. Rate constants were dependent on the initial MPB-07 concentration, temperature, and pH. At pH 7.4, and for concentrations from 1 to 125 ,M, half-lives ranged from 0.681,±,0.047 to 4.54,±,0.28 h. The Arrhenius plot was linear and activation energy was calculated to be 20.7 kJ,·,mol,1. Analysis by chemical ionization-mass spectrometry showed that the chlorine atom of the MPB-07 molecule might be replaced by an OH group during the photodegradation process. In the dark, MPB-07 in solutions at pH 7.4 was found to be stable over a 6-week period. In conclusion, MPB-07 is a highly photolabile molecule that should be carefully protected from light when used. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:324,330, 2002 [source] Antibody-immobilized column for quick cell separation based on cell rollingBIOTECHNOLOGY PROGRESS, Issue 2 2010Atsushi Mahara Abstract Cell separation using methodological standards that ensure high purity is a very important step in cell transplantation for regenerative medicine and for stem cell research. A separation protocol using magnetic beads has been widely used for cell separation to isolate negative and positive cells. However, not only the surface marker pattern, e.g., negative or positive, but also the density of a cell depends on its developmental stage and differentiation ability. Rapid and label-free separation procedures based on surface marker density are the focus of our interest. In this study, we have successfully developed an antiCD34 antibody-immobilized cell-rolling column, that can separate cells depending on the CD34 density of the cell surfaces. Various conditions for the cell-rolling column were optimized including graft copolymerization, and adjustment of the column tilt angle, and medium flow rate. Using CD34-positive and -negative cell lines, the cell separation potential of the column was established. We observed a difference in the rolling velocities between CD34-positive and CD34-negative cells on antibody-immobilized microfluidic device. Cell separation was achieved by tilting the surface 20 degrees and the increasing medium flow. Surface marker characteristics of the isolated cells in each fraction were analyzed using a cell-sorting system, and it was found that populations containing high density of CD34 were eluted in the delayed fractions. These results demonstrate that cells with a given surface marker density can be continuously separated using the cell rolling column. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] The Laulimalide Family: Total Synthesis and Biological Evaluation of Neolaulimalide, Isolaulimalide, Laulimalide and a Nonnatural AnalogueCHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2009Andreas Gollner Dipl.-Ing. Abstract A sensitive family: The first total synthesis of the antitumor agents neolaulimalide and isolaulimalide as well as a highly efficient route to laulimalide is described. A Kulinkovich reaction followed by a cyclopropyl,allyl rearrangement is used to install the exo -methylene group. The cytotoxicity of neolaulimalide could be confirmed for the first time since its original isolation and it could be shown that it induces tubulin polymerization as efficiently as laulimalide. We herein describe in full detail the first total synthesis of the antitumor agents neolaulimalide and isolaulimalide as well as a highly efficient route to laulimalide. A Kulinkovich reaction followed by a cyclopropyl,allyl rearrangement is used to install the exo -methylene group. The C2,C16 aldehyde fragment is coupled with the C17,C28 sulfone fragments by a highly (E)-selective Julia,Lythgoe,Kocienski olefination to deliver the key intermediates of all three syntheses. Various conditions for the Yamaguchi macrolactonization are applied to close the individual macrocycles. Finally a carefully elaborated endgame was developed to solve the problem of acyl migration in the case of neolaulimalide. All compounds were tested against several cell lines. The cytotoxicity of neolaulimalide could be confirmed for the first time since its original isolation and it could be shown that it induces tubulin polymerization as efficiently as laulimalide. [source] Monitoring of acromegaly: what should be performed when GH and IGF-1 levels are discrepant?CLINICAL ENDOCRINOLOGY, Issue 2 2009Pamela U. Freda Summary Monitoring of a patient with acromegaly requires periodic evaluation of levels of GH and IGF-1, the biochemical markers of this disease. Although the results of these two tests are usually concordant, they can be discrepant and how to proceed when they are can be a challenging clinical problem. In some cases, IGF-1 levels are normal yet GH suppression after oral glucose is abnormal; this pattern may be due to persistent GH dysregulation despite remission. In other cases, IGF-1 levels are elevated yet GH suppression appears to be normal; this pattern may be observed if the cutoff for GH suppression is inappropriately high for the GH assay being used. Various conditions known to alter GH and IGF-1 including malnutrition, thyroid disease and oestrogen use as well as the potential for methodological or normative data issues with the GH and IGF-1 assays should be considered in the interpretation of discrepant results. When a known cause of the discrepancy other than acromegaly is not identified, a clinical decision about the patient's therapy needs to be made. We adjust treatment in most patients whose results are discrepant based on the IGF-1 level, continuing current treatment if it is persistently normal or modifying this if it is elevated. The clinical picture of the patient, however, also needs to be incorporated into this decision. All patients should have continued periodic surveillance of both GH and IGF-1 levels. [source] Hardness of a crystalline lens and accommodationACTA OPHTHALMOLOGICA, Issue 2009A CHUPROV Purpose to estimate influence of mechanical characteristics of a crystalline lens on accommodation possibility Methods At 56 patients with a various condition of a crystalline lens we defined amplitude of accommodation by a method of finding of the nearest and far points. Mechanical properties of a crystalline lens defined by the original ultrasonic method. At the heart of a method, use of the information which formed at distribution of a mechanical wave in non-uniform environments. Results We revealed the strong inverse negative relationship between volume of accommodation and hardness of a crystalline lens nucleus - the factor of correlation was equal -0,63 (? <0,01). Conclusion One of the reasons of the accommodation worsening is the increase of a crystalline lens mechanical hardness [source] LEARNING PRECONDITIONS FOR PLANNING FROM PLAN TRACES AND HTN STRUCTURECOMPUTATIONAL INTELLIGENCE, Issue 4 2005Okhtay Ilghami A great challenge in developing planning systems for practical applications is the difficulty of acquiring the domain information needed to guide such systems. This paper describes a way to learn some of that knowledge. More specifically, the following points are discussed. (1) We introduce a theoretical basis for formally defining algorithms that learn preconditions for Hierarchical Task Network (HTN) methods. (2) We describe Candidate Elimination Method Learner (CaMeL), a supervised, eager, and incremental learning process for preconditions of HTN methods. We state and prove theorems about CaMeL's soundness, completeness, and convergence properties. (3) We present empirical results about CaMeL's convergence under various conditions. Among other things, CaMeL converges the fastest on the preconditions of the HTN methods that are needed the most often. Thus CaMeL's output can be useful even before it has fully converged. [source] Mach Probe Measurements in Unmagnetized Plasmas with Subsonicand Supersonic FlowCONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-6 2006A. Ando Abstract Characteristics of an up-down type Mach probe are investigated by using a directional Langmuir probe (DLP) in unmagnetized plasmas with subsonic and supersonic flow produced by a magneto-plasma-dynamic arcjet (MPDA). The ion acoustic Mach number Mi is derived from plasma flow velocity Up and ion temperature Ti measured by spectroscopy and electron temperature Te by Langmuir probe. The obtained values of Mi are compared to the DLP data in various conditions of plasma flow and the coefficient of Mc in the Mach probe formula,Mi = Mc ln(Jup/Jdown ) , is evaluated. The obtained data are also compared with Hutchinson's PIC simulation results in an unmagnetized plasma and are in good agreement with each other. The dependence of ln(Jup/Jdown ) on cos, can be expressed as a quadratic function under subsonic (Mi < 1) and supersonic (Mi > 1) flow, so that the up-down type Mach probe can detect the components of plasma flow vector even when the probe collection surface inclines to plasma flow direction. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Cyto-histological correlations inprimary, recurrent, and metastatic bone and soft tissue osteosarcoma.DIAGNOSTIC CYTOPATHOLOGY, Issue 5 2007Institut Curie's experience Abstract To determine diagnostic cytomorphologic features of osteosarcoma on fine-needle aspiration materials, we reviewed the cytologic material and corresponding histologic slides of 126 tumors in 107 patients. Fifty-five (43.6%) tumors were primary, 31 (24.6%) were recurrent, and 40 (31.8%) were metastatic. Review of original cytology reports revealed that 120 (95.3%) tumors were diagnosed as malignant. Six (4.7%) cases were reported as suspicious, false-negative, or unsatisfactory samples. Our findings showed that osteoblastic roundish cells, spindle-shaped cells, reactive giant cells, and osteoid were the most consistent features representative of osteosarcoma. Periosteal reactions, fractures with callous formation, giant cells of osteoclastic type in various conditions, chondrosarcoma with enchondral ossification are entities to consider in the differential diagnosis. Diagn. Cytopathol. 2007;35:270,275. © 2007 Wiley-Liss, Inc. [source] Determination of flurbiprofen enantiomers in plasma using a single-isomer amino cyclodextrin derivative in nonaqueous capillary electrophoresis,ELECTROPHORESIS, Issue 17 2008Anne Rousseau Abstract A nonaqueous capillary electrophoresis (NACE) assay was developed for the separation and determination of flurbiprofen enantiomers in plasma samples using 6-monodeoxy-6-mono(3-hydroxy)propylamino-,-cyclodextrin as chiral selector. The nonaqueous background electrolyte was made up of 40,mM ammonium acetate in methanol (MeOH), and flufenamic acid was employed as internal standard. Solid-phase extraction was used for sample cleanup prior to the NACE separation. The NACE method reproducibility was optimized by evaluating different capillary washing sequences between runs. After having tested various conditions, trifluoroacetic acid (1,M) in MeOH was finally selected. Concerning the solid-phase extraction procedure, good and reproducible analyte recoveries were obtained using MeOH for protein denaturation and a polymeric phase combining hydrophobic interactions with anion exchange properties (Oasis® MAX) was selected as extraction sorbent. The method selectivity was not only demonstrated toward a blank plasma sample but also toward other non-steroidal anti-inflammatory drugs. The method was then successfully validated with respect to response function, trueness, precision, accuracy, linearity and limit of quantification. [source] Comparison of the use of anionic and cationic surfactants for the separation of steroids based on MEKC and sweeping-MEKC modesELECTROPHORESIS, Issue 5-6 2006Hui-Ju Shen Abstract In attempts to improve the selectivity and sensitivity of steroid separation and to determine their migration order, a comparison of the use of anionic and cationic surfactants based on the MEKC and sweeping-MEKC modes was made. A mixture of six steroids (progesterone, 17-hydroxy progesterone, 11-deoxycortisol, corticosterone, cortisone, and cortisol) could be separated and detected by means of the CE/UV-absorption method. The order of migration time for these steroids was compared under various conditions, including acidic/alkaline buffers, anionic/cationic surfactants, and positive/negative applied voltage, causing the direction of the EOF and the migration of micelles to change. The major rules for generally predicting the migration order of steroids are summarized. The detection limits were significantly improved when the sweeping-MEKC mode was applied. [source] Effect of various extraction conditions on the phenolic contents of pomegranate seed oilEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 5 2008Hajar Abbasi Abstract Pomegranate seeds are byproducts of the pomegranate juice industry. Because of the presence of large amounts of certain pharmaceutical and nutraceutical components in the seeds, a proper extraction method to obtain these components is highly demanded in the food industry. In this study, the effect of different extraction methods on the total phenolic contents of the oil extracted from pomegranate seeds of the Malas variety from Shahreza, Iran, was investigated. Four different extraction methods including normal stirring, Soxhlet, microwave irradiation and ultrasonic irradiation using two types of organic solvents as well as a supercritical fluid extraction (SFE) method using CO2 as solvent were applied. The different organic solvents of this study did not indicate any significant differences in the total phenolic contents of the extracted oils, but the extracted oils from the various conditions of SFE indicated wide changes in the amount of phenolic compounds (7.8,72.1,mg/g). The total phenolic content of the extracted oil from one of the SFE runs was several times greater than those in the extracted oils using organic solvents. [source] Effects of hydrogenation parameters on trans isomer formation, selectivity and melting properties of fatEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 3 2008Anar Musavi Abstract Effects of hydrogenation conditions (temperature, hydrogen pressure, stirring rate) on trans fatty acid formation, selectivity and melting behavior of fat were investigated. To this aim, soybean oil was hydrogenated under various conditions and fatty acid composition, trans isomer formation, slip melting point (SMP), solid fat content (SFC) and iodine number (IV) of the samples withdrawn at certain intervals of the reactions were monitored. A constant ratio (0.03%) of Nysosel 222 was used in the various combinations of temperature (150, 165 and 180,°C), stirring speed (500, 750 and 1000,rpm) and hydrogen pressure (1, 2 and 3,bar). Raising the temperature increased the formation of fatty acid isomers, whereas higher stirring rates decreased this formation, while changes in hydrogen pressure had no effect or slightly reduced it, depending on other parameters. Results also indicated that the trans fatty acid ratio increased with IV reduction, reached the highest value when the IV was about 70 and decreased at IV < 70 due to saturation. Selectivity values (S21) at that point ranged between 5.78 and 11.59. Lower temperatures and higher stirring rates decreased not only the trans isomer content but also the S21 values at significant levels. However, same effects were not observed with the changes in hydrogen pressure. It was determined that a high SMP does not necessarily mean a high SFC. Selective conditions produced samples with higher SFC but lower SMP, which is possibly because of higher trans isomer formation as well as lower saturation. [source] Synthesis and Property Studies of CyclotrisazobenzenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2009Raphael Reuter Abstract Azobenzenophanes are fascinating macrocycles, which are of special interest due to their unique photochromic behavior. Cyclotrisazobenzenes 2 (R = H, Br, tBu) were prepared to probe how much strain the photoisomerization of the azobenzene motive can tolerate. The macrocycles were synthesized in an overall yield of 10,20,% from ortho -phenylenediamine (6). Solid-state structures of cyclotrisazobenzenes 2a and 2b were obtained. Irradiation under various conditions did not induce any isomerization.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] The Synthesis of Brominated Tetrafluoro[2.2]paracyclophanes,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2006Lidija Bondarenko Abstract The bromination of the two isomeric tetrafluoro[2.2]paracyclophanes was investigated under various conditions. We found selective conditions for mono- and dibrominationof 1,1,9,9-tetrafluoro[2.2]paracyclophane in high yields. Furthermore, three tetrabromo isomers were characterized. The para-dibromide of 1,1,10,10-tetrafluoro[2.2]paracyclophane was prepared in high yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Synthesis and Stereochemical Aspects of 2,6-Disubstituted Perhydroazulenes , Core Units for a New Class of Liquid Crystalline MaterialsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2006Zakir Hussain Abstract A novel approach for the synthesis of cis/trans -fused perhydroazulenes 13,19 is reported. The stereochemistry of the derivatives of carbene addition products 9a,c/20,22, of the 2,6-disubstituted perhydroazulenes 12a,c/23,25, and that of compounds 26,27 has been studied by single-crystal X-ray crystallography. The hydrogenation of the tropylidene to the perhydroazulene skeleton under various conditions is described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Correlation of psoriasis activity with abundance of CD25+CD8+ T cells: conditions for cloning T cells from psoriatic plaquesEXPERIMENTAL DERMATOLOGY, Issue 10 2004Wayan M. Kohlmann Abstract:, The role of T cells in the pathogenesis of psoriasis is widely acknowledged. However, key aspects of their precise function in the disease as well as the relative pathogenic contribution of T-cell subsets are still unknown. T-cell clones have been isolated from psoriatic plaques but a study of conditions affecting the isolation and expansion of T-cell clones from psoriatic skin has not been reported to date. Here, we observe a correlation of disease activity with the frequency of the CD3+CD8+CD25+ subset. We show that prolonged in vitro culture changes the phenotypic subset distribution of T-cell lines derived from psoriatic skin and that T-cell clones can be isolated by sorting of CD25+ cells emigrated from skin fragments after 7 days. We evaluate various conditions affecting expansion of psoriatic T-cell clones in vitro and show that blocking apoptosis can facilitate proliferation of activated T-cell clones in vitro. Our results indicate a prominent role of the CD8+CD25+ T-cell subset in disease pathogenesis and should be useful in the design of experiments aiming at a systematic analysis of the specificity of clones present in psoriatic plaques. [source] Strength recovery of machined Al2O3/SiC composite ceramics by crack healingFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 12 2007M. ONO ABSTRACT Alumina is used in various fields as a machine component. However, it has a low fracture toughness, which is a weakness. Thus, countless cracks may be initiated randomly by machining, and these cracks decrease the component's mechanical properties and reliability. To overcome this problem, a crack-healing ability could be a very useful technology. In this study, Al2O3/SiC composite was sintered. This alumina exhibits excellent crack-healing ability. Small specimens for a bending test were made from the Al2O3/SiC. A semicircular groove was machined using a diamond ball-drill. The machining reduced the local fracture stress from approximately 820,300 MPa. The machined specimens were crack-healed under various conditions. The fracture stress of these specimens after crack healing was evaluated systematically from room temperature (RT) to 1573 K. It was found that the local fracture stress of the machined specimen recovered almost completely after crack healing. Therefore, it was concluded that crack healing could be an effective method for improving the structural integrity of machined alumina and reducing machining costs. [source] Complete reconstitution of an ATP-binding cassette transporter LolCDE complex from separately isolated subunitsFEBS JOURNAL, Issue 12 2007Kyoko Kanamaru The LolCDE complex of Escherichia coli belongs to the ATP-binding cassette transporter superfamily and mediates the detachment of lipoproteins from the inner membrane, thereby initiating lipoprotein sorting to the outer membrane. The complex is composed of one copy each of membrane subunits LolC and LolE, and two copies of ATPase subunit LolD. To establish the conditions for reconstituting the LolCDE complex from separately isolated subunits, the ATPase activities of LolD and LolCDE were examined under various conditions. We found that both LolD and LolCDE were inactivated on incubation at 30 °C in a detergent solution. ATP and phospholipids protected LolCDE, but not LolD. Furthermore, phospholipids reactivated LolCDE even after its near complete inactivation. LolD was also protected from inactivation when membrane subunits and phospholipids were present together, suggesting the phospholipid-dependent reassembly of LolCDE subunits. Indeed, the functional lipoprotein-releasing machinery was reconstituted into proteoliposomes with E. coli phospholipids and separately purified LolC, LolD and LolE. Preincubation with phospholipids at 30 °C was essential for the reconstitution of the functional machinery from subunits. Strikingly, the lipoprotein-releasing activity was also reconstituted from LolE and LolD without LolC, suggesting the intriguing possibility that the minimum lipoprotein-releasing machinery can be formed from LolD and LolE. We report here the complete reconstitution of a functional ATP-binding cassette transporter from separately purified subunits. [source] Disulfide bond formation through Cys186 facilitates functionally relevant dimerization of trimeric hyaluronan-binding protein 1 (HABP1)/p32/gC1qRFEBS JOURNAL, Issue 1 2002Babal Kant Jha Hyaluronan-binding protein 1 (HABP1), a ubiquitous multifunctional protein, interacts with hyaluronan, globular head of complement component 1q (gC1q), and clustered mannose and has been shown to be involved in cell signalling. In vitro, this recombinant protein isolated from human fibroblast exists in different oligomeric forms, as is evident from the results of various independent techniques in near-physiological conditions. As shown by size-exclusion chromatography under various conditions and glutaraldehyde cross-linking, HABP1 exists as a noncovalently associated trimer in equilibrium with a small fraction of a covalently linked dimer of trimers, i.e. a hexamer. The formation of a covalently-linked hexamer of HABP1 through Cys186 as a dimer of trimers is achieved by thiol group oxidation, which can be blocked by modification of Cys186. The gradual structural transition caused by cysteine-mediated disulfide linkage is evident as the fluorescence intensity increases with increasing Hg2+ concentration until all the HABP1 trimer is converted into hexamer. In order to understand the functional implication of these transitions, we examined the affinity of the hexamer for different ligands. The hexamer shows enhanced affinity for hyaluronan, gC1q, and mannosylated BSA compared with the trimeric form. Our data, analyzed with reference to the HABP1/p32 crystal structure, suggest that the oligomerization state and the compactness of its structure are factors that regulate its function. [source] RUNOFF PRODUCTION AND EROSION PROCESSES ON A DEHESA IN WESTERN SPAIN,GEOGRAPHICAL REVIEW, Issue 3 2002ANTONIO CEBALLOS ABSTRACT. Runoff generation and soil erosion were investigated at the Guadalperalón experimental watershed (western Spain), within the land-use system known as dehesa, or open, managed evergreen forests. Season and type of surface were found to control runoff and soil-loss rates. Five soil units were selected as representative of surface types found in the study area: hillslope grass, bottom grass, tree cover, sheep trails, and shrub cover. Measurements were made in various conditions with simulated rainfall to gain an idea of the annual variation in runoff and soil loss. Important seasonal differences were noted due to surface cover and moisture content of soil, but erosion rates were determined primarily by runoff. Surfaces covered with grass and shrubs always showed less erosion; surfaces covered with holm oaks showed higher runoff rates, due to the hydrophobic character of the soils. Concentrations of runoff sediment during the simulations confirmed that erosion rates at the study site depended directly on the sediment available on the soil surface. [source] BEAM , Geoelectrical Ahead Monitoring for TBM-DrivesGEOMECHANICS AND TUNNELLING, Issue 5 2008Arnim Kaus Dr. rer.nat. BEAM is a non-intrusive focused-electrical induced polarisation ground prediction technique, permanently operating while TBM tunnelling. Main components of the survey system are the measuring unit placed in the TBM operator cabin and special adapted excavation tools which are used as electrodes. The unit is connected to the guidance system and receives the boring signal which allows fully automatic data acquisition and visualisation in real-time on an integrated monitor. Communication facilities transfer the forecast results to every accredited computer world wide simultaneously. Based on the measuring data the percentage frequency effect PFE and the resistivity R, an advanced evaluation software is established for geoelectrical-geological/hydrogeological classification and interpretation. Selected case studies from international TBM projects are outlined with prediction results of different kinds of exploration targets and geological situations. Since 2000 the geophysical probing system is fulfilling the practical demands under the rough and various conditions of TBM tunnelling work by indicating reliable results in hard rock as well as in soft ground. BEAM , Geoelektrische Vorauserkundung für TBM-Vortriebe BEAM ist eine zerstörungsfreie, vortriebsbegleitende Baugrund-Vorauserkundungs-Technologie auf Basis der fokussierend-elektrischen induzierten Polarisation. Das Monitoring-System besteht hauptsächlich aus einem Messgerät, das in der Steuerkabine aufgestellt werden kann, und aus speziell angepassten, bauseits vorhandenen Abbauwerkzeugen und Sicherungsmitteln, die als Elektroden dienen. Die Messeinheit wird mit dem bestehenden Vermessungssystem verbunden und empfängt das Bohrsignal, sodass vollautomatisierte Messungen durchgeführt werden, ohne die Tunnelvortriebsarbeiten zu stören, bei gleichzeitiger Datenauswertung und Visualisierung der Ergebnisse in Echtzeit auf dem integrierten Bildschirm der Einheit. Durch Anschluss an die Kommunikationseinrichtungen der Baustelle lassen sich die Vorauserkundungsdaten zeitgleich an jeden akkreditierten Computer weltweit transferieren. Eine innovative Auswertesoftware bewerkstelligt die geoelektrisch-geologische/hydrogeologische Klassifikation und Interpretation, die auf den Messparametern Prozent Frequenz Effekt PFE und dem Widerstand R basiert. Ausgewählte Fallbeispiele aus internationalen TBM-Projekten zeigen Vorauserkundungsergebnisse unterschiedlicher Explorationsziele und geologischer Situationen. Seit 2000 ist das Vorauserkundungssystem in der Anwendung und zeigt, dass es unter den schwierigen und unterschiedlichen Bedingungen im mechanisierten Tunnelbau sowohl im Hartgestein als auch im Lockergestein im Dauereinsatz zuverlässige Ergebnisse erbringt. [source] Highly Fluorescent Poly(dimethylsiloxane) for On-Chip Temperature MeasurementsADVANCED FUNCTIONAL MATERIALS, Issue 2 2009Jianhua Zhou Abstract This work describes a convenient method to generate a poly(dimethylsiloxane) (PDMS) composite containing ZnO quantum dots (QDs) for whole-chip temperature measurements. This composite is highly fluorescent and very sensitive to temperature changes (0.4,nm,°C,1, compared to 0.1,nm,°C,1 in commonly used CdSe QDs). It also shows extremely high fluorescent stability under various conditions over long time without phase separation or fluorescent changes. Both merits make this composite an ideal material for sensing temperature changes on microfluidic chips. The bonding between the QDs and PDMS is studied by comparing PDMS composites with ZnO QDs of different sizes, and a model is given to elucidate the high stability of this composite. [source] A Screening Model for Injection-Extraction Treatment Well Recirculation System DesignGROUND WATER MONITORING & REMEDIATION, Issue 4 2008Monica Y. Wu Implementation of injection-extraction treatment well pairs for in situ, in-well, or on-site remediation may be facilitated by development and application of modeling tools to aid in hydraulic design and remediation technology selection. In this study, complex potential theory was employed to derive a simple one-step design equation and related type curves that permit the calculation of the extraction well capture zone and the hydraulic recirculation between an injection and extraction well pair oriented perpendicular to regional flow. This equation may be used to aid in the design of traditional fully screened injection-extraction wells as well as innovative tandem recirculating wells when an adequate geologic barrier to vertical ground water flow exists. Simplified models describing in situ bioremediation, in-well vapor stripping, and in-well metal reactor treatment efficiency were adapted from the literature and coupled with the hydraulic design equation presented here. Equations and type curves that combine the remediation treatment efficiency with the hydraulic design equation are presented to simulate overall system treatment efficiency under various conditions. The combined model is applied to predict performance of in situ bioremediation and in-well palladium reactor designs that were previously described in the literature. This model is expected to aid practitioners in treatment system screening and evaluation. [source] Effects of Structural Variation on the Photocatalytic Performance of Hydrothermally Synthesized BiVO4,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2006J. Yu Abstract Highly crystalline monoclinic scheelite BiVO4 powders are synthesized from aqueous Bi(NO3)3 and NH4VO3 solutions over a wide range of pH by a hydrothermal process. BiVO4 powders with various morphologies, surface textures, and grain shapes are selectively synthesized by adjusting the pH. The dependence of the Raman peak position and intensity on the synthesis conditions indicates that the symmetry distortions in the local structure of the synthesized BiVO4 are affected by the preparation conditions. These variations in the local structure result in the modification of the electronic structure of BiVO4, which results in a blue-shift in the UV-vis absorption spectrum of hydrothermally synthesized BiVO4 in comparison with a well-crystallized sample prepared by homogeneous coprecipitation. The photocatalytic activities for O2 evolution from an aqueous AgNO3 solution under visible-light irradiation are strongly dependent on the pH used in the synthesis. The differences in the photocatalytic activities between BiVO4 samples prepared under various conditions is attributed to the degree of structural distortion, leading to differences in the mobility of photogenerated holes formed in the valence band, which consists of Bi,6s and O,2p orbitals. [source] Quality inspection in polymer processing by a thermophysical handy testerHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2006Yasuyuki Koshikawa Abstract This paper presents the applicability of a thermophysical handy tester for quality inspection and diagnostic technique such as in situ measurement of polymeric resin products. Influence of crystallinity known as a rating factor of quality, or filler concentration upon thermal conductivity is determined for the case of unsaturated polyester resin products by using the tester. Consequently, good correlations between the thermal conductivity and the crystallinity or the filler concentration are certified. The variation or the distribution of thermal conductivity of products molded under various conditions can be detected nondestructively using the tester. As an example, the thermal conductivity distribution around the forming gate is demonstrated, indicating the density-uniformity of the resin product. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(6): 421,433, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20124 [source] Is Helicobacter pylori a True Microaerophile?HELICOBACTER, Issue 4 2006Stephanie Bury-Moné Abstract Background:, There is no general consensus about the specific oxygen and carbon dioxide requirements of the human pathogen Helicobacter pylori. This bacterium is considered a microaerophile and consequently, it is grown under atmospheres at oxygen tensions 5,19% and carbon dioxide tensions 5,10%, both for clinical and basic and applied research purposes. The current study compared the growth of H. pylori in vitro, under various gas atmospheres, and determined some specific changes in the physiology of bacteria grown under different oxygen partial pressures. Methods:, Measurements of bacterial growth under various conditions were carried out employing classical solid and liquid culture techniques. Enzymatic activities were measured using spectrophotometric assays. Results:,H. pylori and all the other Helicobacter spp. tested had an absolute requirement for elevated carbon dioxide concentrations in the growth atmosphere. In contrast with other Helicobacter spp., H. pylori can tolerate elevated oxygen tensions when grown at high bacterial concentrations. Under 5% CO2, the bacterium showed similar growth in liquid cultures under oxygen tensions from microaerobic (< 5%) to fully aerobic (21%) at cell densities higher than 5 × 105 cfu/ml for media supplemented with horse serum and 5 × 107 cfu/ml for media supplemented with ,-cyclodextrin. Evidence that changes occurred in the physiology of H. pylori was obtained by comparing the activities of ferredoxin:NADH (nicotinamide adenine dinucleotide) oxidoreductases of bacteria grown under microaerobic and aerobic atmospheres. Conclusions:,H. pylori is a capnophile able to grow equally well in vitro under microaerobic or aerobic conditions at high bacterial concentrations, and behaved like oxygen-sensitive microaerophiles at low cell densities. Some characteristics of H. pylori cells grown in vitro under microaerobic conditions appeared to mimic better the physiology of organisms grown in their natural niche in the human stomach. [source] | |||||||||||||||||||||||||||||||||||||||||||