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Selected AbstractsThrough oven transfer adsorption,desorption interface for the analysis of methyl jasmonate in aromatic samples by on-line RPLC-GCJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2008Gema Flores Abstract A fully automated method for the determination of medium volatility compounds in aromatic samples was developed. Specifically, the determination of methyl jasmonate in jasmine fragrances was performed by using the through oven transfer adsorption,desorption (TOTAD) interface for the on-line coupling between RPLC-GC. A study of the most relevant variables involved in the performance of the TOTAD interface for medium volatility compounds was carried out by testing different values of helium flow (100, 300, 400, and 500 mL/min), transfer speed (0.1, 0.3, 0.5, and 2.0 mL/min), and methanol/water percentages (86:14, 85:15, 83:17, 80:20, and 70:30). The method developed provided satisfactory repeatability (RSD for retention times of 0.15% and for peak areas of 9.4%) and recovery (71%) as well as excellent LOD (0.01 mg/L) for methyl jasmonate in commercial jasmine essence under the experimental conditions selected as optimum. Additional advantages of the automated RPLC-TOTAD-GC method proposed in the present work are its rapidness, reliability, and the possibility of directly introducing the sample with no further pretreatment. [source] Noninvasive quantification of human brain ascorbate concentration using 1H NMR spectroscopy at 7,TNMR IN BIOMEDICINE, Issue 3 2010Melissa Terpstra Abstract Ascorbate (Asc, vitamin C) was quantified in the human brain noninvasively using two different 1H NMR spectroscopy methods: short-echo time STEAM and MEGA-PRESS homonuclear editing. Taking advantage of increased sensitivity and chemical shift dispersion at 7,T, Asc was quantified with increased reliability relative to our previous study accomplished at 4,T. Asc concentration quantified from short-echo time spectra measured from the occipital lobe of eight healthy subjects ([Asc],=,1.1,±,0.3,µmol/g, mean,±,SD) was in excellent agreement with Asc concentration quantified from the same volume of interest using homonuclear editing ([Asc],=,1.2,±,0.2,µmol/g). This agreement indicates that at 7,T, Asc can be reliably quantified in the human brain simultaneously with 15 other metabolites. Additional advantages of the short-echo time approach were: shorter measurement time than homonuclear editing and minimal effect of T2 relaxation on Asc quantification. High magnetic field was also beneficial for Asc quantification with MEGA-PRESS because increased chemical shift dispersion enabled editing with full efficiency, which resulted in a supra-linear gain in signal-to-noise ratio relative to 4,T. Copyright © 2009 John Wiley & Sons, Ltd. [source] With phases: how two wrongs can sometimes make a rightACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2010Pietro Roversi In isolation, both weak isomorphous/anomalous difference signals from heavy-atom derivatization and phases from partial molecular-replacement solutions for a subset of the asymmetric unit often fall short of producing interpretable electron-density maps. Phases generated from very partial molecular-replacement models (if generated carefully) can be used to reliably locate heavy-atom sites, even if the signal is not sufficiently strong to allow robust finding of the sites using Patterson interpretation or direct methods. Additional advantages are that using molecular-replacement phases to define the heavy-atom substructure avoids the need for subsequent hand determination and/or origin-choice reconciliation and that the partial model can be used to aid the mask determination during solvent flattening. Two case studies are presented in which it was only by combining experimental and molecular-replacement phasing approaches that the crystal structures could be determined. [source] Bacteria of asymptomatic periradicular endodontic lesions identified by DNA-DNA hybridizationDENTAL TRAUMATOLOGY, Issue 5 2000J. J. Gatti Abstract , Possible inclusion of contaminant bacteria during surgery has been problematic in studies of periradicular lesions of endodontic origin. Therefore, in this study, two different surgical techniques were compared. A second problem is that some difficult to cultivate species may not be detected using bacteriological methods. Molecular techniques may resolve this problem. DNA-DNA hybridization technology has the additional advantage that DNA is not amplified. The purpose of this investigation was to determine if bacteria from periradicular endodontic lesions could be identified using DNA-DNA hybridization. A full thickness intrasulcular mucoperiosteal (IS) flap (n=20) or a submarginal (SM) flap (n=16) was reflected in patients with asymptomatic apical periodontitis. DNA was extracted and incubated with 40 digoxigenin-labeled whole genomic probes. Bacterial DNA was detected in all 36 lesions. Seven probes were negative for all lesions. In patients with sinus tract communication, in teeth lacking intact full coverage crowns, and in patients with a history of trauma, 4,13 probes provided positive signals. Seven probes were positive in lesions obtained by the IS, but not the SM technique. Two probes were in samples obtained with the SM technique, but not the IS. Only Bacteroides forsythus and Actinomyces naeslundii genospecies 2 were present in large numbers using either the IS or the SM technique. The SM flap technique, in combination with DNA-DNA hybridization, appeared to provide excellent data pertaining to periradicular bacteria. These results supported other studies that provide evidence of a bacterial presence and persistence in periradicular lesions. [source] Improved resolution with microchip-based enhanced field inversion electrophoresisELECTROPHORESIS, Issue 11 2003Christopher J. Backhouse Abstract We present an improvement of the field inversion electrophoresis (FIE) method in which the passage of sample such as DNA back and forth within a short length of a microchannel can provide a similar resolution to that of a significantly longer microchannel. In constant field FIE the application of an alternating potential (e.g., +/, V) over short periods of time (e.g., several Hz) can provide enhanced separations of DNA fragments. In contrast, the present method consists of a series of separations, each of much longer duration, under high and low fields in such a way that the resolution is enhanced. This method is readily modeled and allows improved resolution to be obtained from extremely short microchannels (e.g., 8 mm) while requiring relatively low applied voltages (e.g., less than 600 V). An additional advantage is that this method can allow for the same equipment to be used in a rapid, low-resolution mode or in a slower, high-resolution mode through what might be referred to as an automated "zoom" capability. We believe that this method may facilitate the integration of microfluidic devices and microelectronic devices by allowing these devices to be of a similar small scale (< 1 cm). [source] Human immunodeficiency virus-associated progressive multifocal leucoencephalopathy: epidemiology and predictive factors for prolonged survivalEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2007A. K. Drake We performed a retrospective review of cases of human immunodeficiency virus-associated progressive multifocal leucoencephalopathy in four hospitals (three in Australia and one in Hong Kong) between 1987 and 2003 in order to describe the local experience with this disease and to evaluate parameters impacting upon survival. Eighty-seven cases were identified and demographic details, baseline parameters and treatment methods and response were described. Survival was substantially increased in the post-highly active antiretroviral therapy (HAART) era with a median survival increase from 14 to 64 weeks. On multivariate analysis, variables associated with prolonged survival included a CD4 count of >100 cells/,l at diagnosis and the use of HAART post-diagnosis, with no significant additional advantage from the use of neuroactive antiretrovirals. [source] Dronedarone: a new option in atrial fibrillationFUTURE PRESCRIBER, Issue 1 2009Professor A. John Camm MD Many antiarrhythmic agents exploiting new mechanisms of action (as well as modified analogues of traditional antiarrhythmic drugs, with different combinations of ion channel- and receptor-blocking effects and less complicated metabolic profiles) are currently being investigated. Dronedarone is an amiodarone derivative that is devoid of iodine atoms and is believed to have a better safety profile than amiodarone. It is the only antiarrhythmic drug for the treatment of atrial fibrillation (AF) that has been shown to improve survival in high-risk patients. This review provides a contemporary insight into the clinical development of dronedarone, its efficacy and safety in preventing recurrent AF, and its potential additional advantage of improving outcome in patients with AF. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sibship analysis of associations between SNP haplotypes and a continuous trait with application to mammographic densityGENETIC EPIDEMIOLOGY, Issue 4 2010J. Stone Abstract Haplotype-based association studies have been proposed as a powerful comprehensive approach to identify causal genetic variation underlying complex diseases. Data comparisons within families offer the additional advantage of dealing naturally with complex sources of noise, confounding and population stratification. Two problems encountered when investigating associations between haplotypes and a continuous trait using data from sibships are (i) the need to define within-sibship comparisons for sibships of size greater than two and (ii) the difficulty of resolving the joint distribution of haplotype pairs within sibships in the absence of parental genotypes. We therefore propose first a method of orthogonal transformation of both outcomes and exposures that allow the decomposition of between- and within-sibship regression effects when sibship size is greater than two. We conducted a simulation study, which confirmed analysis using all members of a sibship is statistically more powerful than methods based on cross-sectional analysis or using subsets of sib-pairs. Second, we propose a simple permutation approach to avoid errors of inference due to the within-sibship correlation of any errors in haplotype assignment. These methods were applied to investigate the association between mammographic density (MD), a continuously distributed and heritable risk factor for breast cancer, and single nucleotide polymorphisms (SNPs) and haplotypes from the VDR gene using data from a study of 430 twins and sisters. We found evidence of association between MD and a 4-SNP VDR haplotype. In conclusion, our proposed method retains the benefits of the between- and within-pair analysis for pairs of siblings and can be implemented in standard software. Genet. Epidemiol. 34: 309,318, 2010. © 2009 Wiley-Liss, Inc. [source] Precise/ Small Sample Size Determinations of Lithium Isotopic Compositions of Geological Reference Materials and Modern Seawater by MC-ICP-MSGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2004Alistair B. Jeffcoate composition isotopique de Li; matériaux de référence silicates; eau de mer; MC-ICP-MS; Li standard The Li isotope ratios of four international rock reference materials, USGS BHVO-2, GSJ JB-2, JG-2, JA-1 and modern seawater (Mediterranean, Pacific and North Atlantic) were determined using multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). These reference materials of natural samples were chosen to span a considerable range in Li isotope ratios and cover several different matrices in order to provide a useful benchmark for future studies. Our new analytical technique achieves significantly higher precision and reproducibility (< ± O.3%o 2s) than previous methods, with the additional advantage of requiring very low sample masses of ca. 2 ng of Li. Les rapports isotopiques du Li de 4 matériaux de référence, de provenance Internationale, BHVO-2, JB-2, JG-2, JA-1 et d'eau de mer (Méditerranée, Pacifique et Atlantique Nord) ont été déterminés par MC-ICP-MS (spectrométrie de masse avec source à plasma induit à multicollection). Ces matériaux de référence naturels ont été choisis car ils balaient un large champ des rapports isotopiques du Lithium et couvrent différentes matrices afin de fournir un point de repère utile pour les études futures. Notre nouvelle technique analytique permet d'atteindre une précision et une reproductibilité (< ± 0.3%. 2s) nettement supérieures à celles des méthodes précédemment utilisées et présente I'avantage de pouvoir travailler avec des échantillons de petite masse, , 2 ng de Li. [source] Efficient implicit finite element analysis of sheet forming processesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2003A. H. van den Boogaard Abstract The computation time for implicit finite element analyses tends to increase disproportionally with increasing problem size. This is due to the repeated solution of linear sets of equations, if direct solvers are used. By using iterative linear equation solvers the total analysis time can be reduced for large systems. For plate or shell element models, however, the condition of the matrix is so ill that iterative solvers do not reach the huge time-savings that are realized with solid elements. By introducing inertial effects into the implicit finite element code the condition number can be improved and iterative solvers perform much better. An additional advantage is that the inertial effects stabilize the Newton,Raphson iterations. This also applies to quasi-static processes, for which the inertial effects finally do not affect the results. The presented method can readily be implemented in existing implicit finite element codes. Industrial size deep drawing simulations are executed to investigate the performance of the recommended strategy. It is concluded that the computation time is decreased by a factor of 5 to 10. Copyright © 2003 John Wiley & Sons, Ltd. [source] A lattice Boltzmann method for solute transportINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 8 2009Jian Guo Zhou Abstract A lattice Boltzmann method is developed for solute transport. Proper expressions for the local equilibrium distribution functions enable the method to be formulated on rectangular lattice with the same simple procedure as that on a square lattice. This provides an additional advantage over a lattice Boltzmann method on a square lattice for problems characterized by dominant phenomenon in one direction and relatively weak in another such as solute transport in shear flow over a narrow channel, where the problems can efficiently be approached with fine and coarse meshes, respectively, resulting in more efficient algorithm. The stability conditions are also described. The proposed method on a square lattice is naturally recovered when a square lattice is used. It is verified by solving four tests and compared with the analytical/exact solutions. They are in good agreement, demonstrating that the method is simple, accurate and robust for solute transport. Copyright © 2008 John Wiley & Sons, Ltd. [source] Use of Coaxial Gas Jackets to Stabilize Taylor Cones of Volatile Solutions and to Induce Particle-to-Fiber Transitions,ADVANCED MATERIALS, Issue 2 2004G. Larsen A novel method to control the stability of Taylor cones during electrospinning/electrospray of solutions with highly volatile solvents is presented. An additional advantage is that fiber-to-particle transitions are also controlled without changing the chemistry or the voltage/current characteristics. The Figure shows the transition from particles to fibers effected by simply changing the gas flow rate through an outer capillary. [source] Sharpless Asymmetric Dihydroxylation of Olefins in WaterSurfactant Media with Recycling of the Catalytic System by Membrane NanofiltrationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2008Abstract This paper presents a new and more sustainable alternative approach for the Sharpless catalytic asymmetric dihydroxylation (AD) of olefins using a water/surfactant system as reaction media. The AD reaction was performed using several cationic and anionic surfactants allowing yields and enantiomeric excesses higher or comparable with the conventional systems (using organic mixtures). The use of this water/surfactant medium offers the additional advantage of performing the reactions without the need of a slow addition of olefins. Asymmetric dihydroxylation of 1-hexene in a 1.5,mM sodium cholate aqueous solution, using N -methylmorpholine N -oxide (NMO) as co-oxidant was selected as model system to evaluate the feasibility of recycling the Sharpless catalytic system by nanofiltration. The reaction media was processed by nanofiltration, the product was isolated in the permeate, whereas the catalytic system and surfactant were retained by the membrane and recycled through six successive reactions, improving the catalyst turn-over number. The experimental results were compared with the ones calculated on the basis of mass balances, membrane rejections to product and reaction yields. [source] Strategies to Improve the Use Efficiency of Mineral Fertilizer Nitrogen Applied to Winter WheatJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2002K. Blankenau Recovery of fertilizer nitrogen (N) applied to winter wheat crops at tillering in spring is lower than that of N applied at later growth stages because of higher losses and immobilization of N. Two strategies to reduce early N losses and N immobilization and to increase N availability for winter wheat, which should result in an improved N use efficiency (= higher N uptake and/or increased yield per unit fertilizer N), were evaluated. First, 16 winter wheat trials (eight sites in each of 1996 and 1997) were conducted to investigate the effects of reduced and increased N application rates at tillering and stem elongation, respectively, on yield and N uptake of grain. In treatment 90-70-60 (90 kg N ha,1 at tillering, 70 kg N ha,1 at stem elongation and 60 kg N ha,1 at ear emergence), the average values for grain yield and grain N removal were up to 3.1 and 5.0 % higher than in treatment 120-40-60, reflecting conventional fertilizer practice. Higher grain N removal for the treatment with reduced N rates at tillering, 90-70-60, was attributed to lower N immobilization (and N losses), which increased fertilizer N availability. Secondly, as microorganisms prefer NH4+ to NO3, for N immobilization, higher net N immobilization would be expected after application of the ammonium-N form. In a pot experiment, net N immobilization was higher and dry matter yields and crop N contents at harvest were lower with ammonium (ammonium sulphate + nitrification inhibitor Dicyandiamide) than with nitrate (calcium nitrate) nutrition. Five field trials were then conducted to compare calcium nitrate (CN) and calcium ammonium nitrate (CAN) nutrition at tillering, followed by two CAN applications for both treatments. At harvest, crop N and grain yield were higher in the CN than in the CAN treatment at each N supply level. In conclusion, fertilizer N use efficiency in winter wheat can be improved if N availability to the crops is increased as a result of reduced N immobilization (and N losses) early in the growth period. N application systems could be modified towards strategies with lower N applications at tillering compensated by higher N dressing applications later. An additional advantage is expected to result from use of nitrate-N fertilizers at tillering. Strategien zur Verbesserung der Effizienz von Düngerstickstoff in Winterweizen Aus früheren Versuchen mit Winterweizen ist bekannt, daß zur Ernte die Wiederfindung von im Frühjahr zur Bestokkung gedüngtem Stickstoff (N) geringer ist, als die von N aus Spätgaben. Die Ursachen liegen in einer höheren mikrobiell-bedingten Netto-N-Immobilisation, aber auch N-Verlusten zwischen Bestockung und Schoßbeginn im Vergleich zu späteren Wachstumstadien begründet. In den vorliegenden Versuchen wurden zwei Strategien getestet, um insbesondere die früh in der Vegetation auftretende Netto-N-Immobilisation zu vermindern. Die dadurch erwartete erhöhte N-Verfügbarkeit sollte zu einer erhöhten N-Effizienz (höherer N-Entzug/Ertrag bezogen auf die N-Düngung) führen. 1996 und 1997 wurden jeweils 8 Feldversuche mit Winterweizen durchgeführt, um den Einfluß einer reduzierten Andüngung bei gleichzeitig erhöhter Schossergabe im Vergleich zur konventionellen N-Düngung zu untersuchen. Tatsächlich wurden in dem Prüfglied 90-70-60 (N-Sollwertdüngung: 90 kg N ha,1, Schossergabe: 70 kg N ha,1, Ährengabe: 60 kg N ha,1) im Mittel bis zu 3.1 % höhere Erträge und 5.0 % höhere N-Abfuhren mit dem Korn im Vergleich zur konventionellen Variante 120-40-60 (N-Sollwertdüngung: 120 kg N ha,1, Schossergabe: 40 kg N ha,1 und Ährengabe: 60 kg N ha,1) erzielt. Die höhere N-Abfuhr kann auf eine erhöhte N-Verfügbarkeit infolge geringerer mikrobieller N-Festlegung zurückgeführt werden. Da die vornehmlich heterotrophen Bodenmikroorganismen bevorzugt NH4+ gegenüber NO3, immobilisieren, kann eine höhere N-Immobilisation bei Ammonium-Düngung erwartet werden. Tatsächlich wurden in einem Gefäßversuch nach Düngung von Ammoniumsulfat (+ Nitrifikationshemmer Dicyandiamid) geringere Trokkenmasseerträge und N-Aufnahmen von Weizenpflanzen erzielt als mit Calciumnitrat. Für die Ammoniumsulfatvariante ergab sich eine höhere Netto-N-Immobilisation. Danach wurde in fünf Feldversuchen mit Winterweizen der Einfluß einer Andüngung mit Nitrat (Calciumnitrat) im Vergleich zur Verwendung des ammoniumhaltigen Kalkammonsalpeters (KAS) auf die N-Aufnahme und den Kornertrag untersucht (beide Varianten erhielten KAS als Spätgaben). In der nitratangedüngten Variante wurden zum Teil signifikant höhere Ertäge und N-Aufnahmen in Korn und Stroh ermittelt. Aus den dargestellten Versuchen kann gefolgert werden, daß die Düngerstickstoff-Effizienz verbessert werden kann, wenn vor allem die N-Immobilisation (und eventuell auch N-Verluste) in frühen Wachstumsstadien zwischen Bestockung und Schoßbeginn verringert und so die N-Verfügbarkeit erhöht wird. Es kann empfohlen werden Winterweizenbestände mit geringeren N-Mengen , als nach N-Sollwert 120 kg N ha,1 vorgesehen , anzudüngen und die Schossergabe entsprechend zu erhöhen. Die Verwendung von nitrathaltigen Düngern bei der Andüngung ist von Vorteil. [source] The relative roles of domestication, rearing environment, prior residence and body size in deciding territorial contests between hatchery and wild juvenile salmonJOURNAL OF APPLIED ECOLOGY, Issue 3 2003Neil B. Metcalfe Summary 1Interactions between captive-reared and wild salmonids are frequent because hatcheries annually rear millions of fish for release in conservation programmes while many thousands of domesticated fish escape from fish farms. However, the outcome of competition between captive-reared and wild fish is not clear: wild fish may be smaller and less aggressive than hatchery fish, but they have more local experience and a prior residence advantage. Moreover, it is important to know whether any competitive differences are genetic (due to the process of domestication) or due to the rearing environment. 2We therefore examined the factors influencing competition for feeding territories in juvenile Atlantic salmon. We studied the effect of domestication by using three independent stocks of both domesticated and wild-origin fish, all of which were reared in a common hatchery environment. We also used fish from the same wild stocks that had been living in the wild. Territorial contests were staged in stream tank compartments between pairs of fish differing in origin or rearing environment; the relative importance of body size and prior residence was also assessed. 3All three stocks of domesticated fish were generally dominant over wild-origin fish when both had been raised in a common hatchery environment. If the wild-origin fish were given a 2-day period of prior residence on the territory this asymmetry in dominance was reversed. However, domesticated fish did not gain any additional advantage from being prior residents. The relative body size of the two contestants had a negligible effect on contest outcomes. 4Truly wild fish (i.e. those of wild origin that had also grown up in the wild) were generally dominant over domesticated or wild-origin fish that had been hatchery-reared. Differences in body size between contestants had no effect on the outcome. 5Synthesis and applications. These results show that, while juvenile farmed Atlantic salmon are inherently more aggressive than wild-origin fish, the hatchery environment reduces their ability to compete for territories with wild resident fish. Rearing salmon in conventional hatcheries for later release into the wild where natural populations already exist may not be a prudent conservation measure; it is preferable to plant eggs or first-feeding fry rather than attempt to ,help' the fish by rearing them through the early life stages. [source] Bacterial synthesis of poly(hydroxybutyrate- co-hydroxyvalerate) using carbohydrate-rich mahua (Madhuca sp.) flowersJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007P.K. Anil Kumar Abstract Aims:, The objective of the present work was to utilize an unrefined natural substrate namely mahua (Madhuca sp.) flowers, as a carbon source for the production of bacterial polyhydroxyalkanoate (PHA) copolymer by Bacillus sp-256. Methods and Results:, In the present work, three bacterial strains were tested for PHA production on mahua flower extract (to impart 20 g l,1 sugar) amongst which, Bacillus sp-256 produced higher concentration of PHA in its biomass (51%) compared with Rhizobium meliloti (31%) or Sphingomonas sp (22%). Biosynthesis of poly(hydroxybutyrate-co-hydroxyvalerate) , P(HB-co-HV) , of 90 : 10 mol% by Bacillus sp-256 was observed by gas chromatographic analysis of the polymer. Major component of the flower is sugars (57% on dry weight basis) and additionally it also contains proteins, vitamins, organic acids and essential oils. The bacterium utilized malic acid present in the substrate as a co-carbon source for the copolymer production. The flowers could be used in the form of aqueous extract or as whole flowers. PHA content of biomass (%) and yield (g l,1) in a 3·0-l stirred tank fermentor after 30 h of fermentation under constant pH (7) and dissolved oxygen content (40%) were 54% and 2·7 g l,1, respectively. Corresponding yields for control fermentation with sucrose as carbon source were 52% and 2·5 g l,1. The polymer was characterized by proton NMR. Conclusions:, Utilization of mahua flowers, a natural substrate for bacterial fermentation aimed at PHA production, had additional advantage, as the sugars and organic acids present in the flowers were metabolized by Bacillus sp-256 to synthesize P(HB-co-HV) copolymer. Significance and Impact of the Study:, Literature reports on utilization of suitable cheaper natural substrate for PHA copolymer production is scanty. Mahua flowers used in the present experiment is a cheaper carbon substrate compared with several commercial substrates and it is rich in main carbon as well as co-carbon sources that can be utilized by bacteria for PHA copolymer production. [source] The use of sodium formate for the recovery of precious metals from acidic base metal effluentsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2001Herman G Julsing Abstract Zinc was used for the reduction of the platinum group metals (PGMs) in acidic effluents. Due to the increasing cost of zinc, sodium formate was investigated as an alternative reductant. In a base metal-containing acidic effluent, called diethylenetriamine barren, sodium formate was used to precipitate the PGMs. This effluent was the filtrate obtained after a precipitation procedure had been used to remove rhodium and iridium. It was found that pH 1.5 was the optimum starting pH for sodium formate reduction. The pH increased to approximately 4.5 after the addition of sodium formate. The optimum concentration of sodium formate was found to be 30,g,dm,3 at a temperature of 100,°C where the process time was 6,h. Platinum and palladium were the most effectively reduced PGMs, both exhibiting an average precipitation efficiency of greater than 99%. Difficulty was experienced with the precipitation of iridium (average precipitation efficiency of 76%). The precipitated PGMs readily dissolved in hydrochloric acid (6,M) and sodium chlorate (2%). A reduction in costs resulted from the discontinuation of the use of zinc for reduction purposes. An additional advantage was that zinc was no longer introduced into the PGM refinery circuits. © 2001 Society of Chemical Industry [source] Predicting and monitoring cancer treatment response with diffusion-weighted MRIJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2010Harriet C. Thoeny MD Abstract An imaging biomarker that would provide for an early quantitative metric of clinical treatment response in cancer patients would provide for a paradigm shift in cancer care. Currently, nonimage based clinical outcome metrics include morphology, clinical, and laboratory parameters, however, these are obtained relatively late following treatment. Diffusion-weighted MRI (DW-MRI) holds promise for use as a cancer treatment response biomarker as it is sensitive to macromolecular and microstructural changes which can occur at the cellular level earlier than anatomical changes during therapy. Studies have shown that successful treatment of many tumor types can be detected using DW-MRI as an early increase in the apparent diffusion coefficient (ADC) values. Additionally, low pretreatment ADC values of various tumors are often predictive of better outcome. These capabilities, once validated, could provide for an important opportunity to individualize therapy thereby minimizing unnecessary systemic toxicity associated with ineffective therapies with the additional advantage of improving overall patient health care and associated costs. In this report, we provide a brief technical overview of DW-MRI acquisition protocols, quantitative image analysis approaches and review studies which have implemented DW-MRI for the purpose of early prediction of cancer treatment response. J. Magn. Reson. Imaging 2010. © 2010 Wiley-Liss, Inc. [source] A portable multi-dimensional gas chromatographic system for field applicationsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12-13 2003Jon H. Wahl Abstract We have constructed and tested a multi-dimensional gas chromatographic system that can be utilized for field portable applications. The chromatographic system is capable of one-dimensional separations and multi-dimensional gas chromatographic (MDGC) separations in a single compact package. Three different general multi-dimensional separation approaches are possible: column switching; traditional heart-cutting; and comprehensive analyses. The MDGC system utilizes a simple 10-port valving approach to accomplish these separations to a single point detector. Because of this valving scheme no hardware change is required to switch between the heart-cut and the comprehensive separation modes, only a software methodology change is required. An additional advantage of this valving approach is that 100% of the first-dimensional effluent is sampled to the second dimension for separation. The system is capable of rapid column heating (room temperature to 250°C in approximately 10 s) and rapid column cooling (250°C to room temperature within approximately 30 s). Preliminary results for heart-cut and comprehensive separations that target five compounds against high concentration levels of complex background are illustrated. [source] Processing and Properties of a Porous Oxide Matrix Composite Reinforced with Continuous Oxide FibersJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2003Magnus G. Holmquist A process to manufacture porous oxide matrix/polycrystalline oxide fiber composites was developed and evaluated. The method uses infiltration of fiber cloths with an aqueous slurry of mullite/alumina powders to make prepregs. By careful manipulation of the interparticle pair potential in the slurry, a consolidated slurry with a high particle density is produced with a sufficiently low viscosity to allow efficient infiltration of the fiber tows. Vibration-assisted infiltration of stacked, cloth prepregs in combination with a simple vacuum bag technique produced composites with homogeneous microstructures. The method has the additional advantage of allowing complex shapes to be made. Subsequent infiltration of the powder mixture with an alumina precursor was made to strengthen the matrix. The porous matrix, without fibers, possessed good thermal stability and showed linear shrinkage of 0.9% on heat treatment at 1200°C. Mechanical properties were evaluated in flexural testing in a manner that precluded interlaminar shear failure before failure via the tensile stresses. It was shown that the composite produced by this method was comparable to porous oxide matrix composites manufactured by other processes using the same fibers (N610 and N720). The ratio of notch strength to unnotch strength for a crack to width ratio of 0.5 was 0.7,0.9, indicating moderate notch sensitivity. Interlaminar shear strength, which is dominated by matrix strength, changed from 7 to 12 MPa for matrix porosity ranging from 38% to 43%, respectively. The porous microstructure did not change after aging at 1200°C for 100 h. Heat treatment at 1300°C for 100 h reduced the strength for the N610 and N720 composites by 35% and 20%, respectively, and increased their brittle nature. [source] Block merging for off-line compressionJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 1 2007Raymond Wan To bound memory consumption, most compression systems provide a facility that controls the amount of data that may be processed at once,usually as a block size, but sometimes as a direct megabyte limit. In this work we consider the Re-Pair mechanism of Larsson and Moffat (2000), which processes large messages as disjoint blocks to limit memory consumption. We show that the blocks emitted by Re-Pair can be postprocessed to yield further savings, and describe techniques that allow files of 500 MB or more to be compressed in a holistic manner using less than that much main memory. The block merging process we describe has the additional advantage of allowing new text to be appended to the end of the compressed file. [source] Liposomes in dermatology todayJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 5 2009J De Leeuw Abstract Liposomes are vesicles consisting of spherical phospholipid bi-layers with specific properties making them useful for topical application of drugs. Liposome research has expanded considerably over the last 30 years and nowadays, it is possible to construct a wide range of liposomes varying in size, phospholipids composition and surface characteristics to suit the specific application for which they are intended. In dermatology, the topical application of liposomes has proven to be of therapeutic value. Liposomes can be used as carriers for hydrophilic as well as lipophilic therapeutic agents because of their amphipathic character. They may improve stabilization of instable drugs by encapsulating them and serve as penetration enhancers facilitating the transport of compounds that otherwise cannot penetrate the skin. Liposomes help in reducing skin irritation by sustaining the release of drugs and by hydration of the epidermis. They also have the potential to target drugs into the pilosebaceous structures and hence they have an additional advantage for treatment of hair follicle-associated disorders. Clinical data indicate that 5-ALA encapsulated in liposomes improves the quality of Fluorescence Diagnosis by ALA-induced Porphyrins (FD) and optimizes the results of Photodynamic Therapy (PDT). Conflicts of interest None declared [source] Canine obesity , an overviewJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 2007J. GOSSELLIN Canine patients are generally regarded as being clinically obese when their body weight is at least 15% above ideal. The incidence of obesity in dogs is thought to be in the range of 20,40% of the general population and, since obesity is known to predispose or exacerbate a range of serious medical conditions, its importance cannot be overstated. Management of obesity through dietary restriction and increased exercise is often difficult to achieve and dependent upon owner compliance. Until recently there has been no authorized therapeutic medication available for weight reduction in dogs, and drugs used in people have proved unsuitable. However, with the development of microsomal triglyceride transfer protein inhibitors for canine use, such as dirlotapide, the veterinarian has a novel method with which to augment traditional weight control programmes. This approach has the additional advantage that weight loss is achieved without dietary restriction or change in exercise regimen, providing encouragement for the owner to comply with subsequent dietary and exercise recommendations, thereby increasing the likelihood for long-term success. [source] An evaluation of invasive and non-invasive tests for the diagnosis of Helicobacter pylori infection in ChineseALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2001B. C. Y. Wong Background: Different tests are available for diagnosing Helicobacter pylori infection. Aim: To compare the most commonly used tests either alone or in combination in Chinese patients with respect to routine clinical use or research purpose. Methods: A total of 294 consecutive dyspeptic patients without previous H. pylori treatment were recruited. During upper endoscopy, biopsies were taken from the antrum and corpus, for a commercially available CLO-test, an in-house rapid urease test, culture, polymerase chain reaction and histological examination. Patients then received a 13C-urea breath test. The H. pylori status of each patient was determined by a concordance of test results. Results: For routine clinical use, histology (antral plus corpus biopsies) had an accuracy of 100%, whilst the rapid urease test had an accuracy of 99.7%. The 13C-urea breath test was equally reliable, with an accuracy of 94.5%. Combinations of two tests did not confer additional advantage over the most accurate single test. For research purposes, the accuracy of using the criteria of two positives out of three diagnostic tests was 100% and equivocal results were not found. Conclusion: Histology with or without a rapid urease test was highly accurate for routine clinical use. Alternatively, the 13C-urea breath test was an equally reliable non-invasive test. The two positives out of three tests approach was highly reliable in predicting H. pylori status of untreated Chinese patients in a research setting. [source] In vivo diffusion tensor imaging of the human optic nerve: Pilot study in normal controlsMAGNETIC RESONANCE IN MEDICINE, Issue 2 2006C.A.M. Wheeler-Kingshott Abstract Diffusion tensor imaging (DTI) of the optic nerve (ON) was acquired in normal controls using zonally oblique multislice (ZOOM) DTI, which excites a small field of view (FOV) using a fast sequence with a shortened EPI echo train. This combines the benefit of low sensitivity to motion (due to the single-shot acquisition used), with the additional advantage of reduced sensitivity to magnetic field susceptibility artifacts. Reducing the bright signal from the fat and cerebrospinal fluid (CSF) surrounding the nerve are key requirements for the success of the presented method. Measurements of mean diffusivity (MD) and fractional anisotropy (FA) indices were made in a coronal section of the middle portion of the optic nerve (ON) in the right (rON) and left (lON) ONs. The average values across 10 healthy volunteers were FArON = 0.64 ± 0.09 and FAlON = 0.57 ± 0.10, and MDrON = (1173 ± 227) × 10,6 mm2 s,1 and MDlON = (1266 ± 170) × 10,6 mm2 s,1. Measurements of the principal eigenvalue of the DT and its orthogonal component were also in agreement with those expected from a highly directional structural organization. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Morphology and fracture properties relationship of epoxy-diamine systems simultaneously modified with polysulfone and poly(ether imide)POLYMER ENGINEERING & SCIENCE, Issue 9 2005M.I. Giannotti An epoxy-diamine system was simultaneously modified with two immiscible thermoplastic polymers, polysulfone (PSF) and poly (ether imide) (PEI), to develop tough materials without adding high quantities of modifiers, in order to avoid the processibility problems caused by the high initial viscosity of the mixtures. The mechanical behavior of blends containing 10 and 15 wt% total thermoplastic was analyzed and compared with the generated morphologies. The scanning electron micrographs (SEM) of the broken surfaces showed that when a small part of PEI is replaced by PSF, drastic changes in morphology, leading to co-continuity between the phases, occurred together with fracture (critical stress intensity factor, KIC) improvements. As an additional advantage, no noticeable decrease in the elastic modulus (E) of final materials was observed. POLYM. ENG. SCI., 45:1312,1318, 2005. © 2005 Society of Plastics Engineers [source] Using nondenaturing mass spectrometry to detect fortuitous ligands in orphan nuclear receptorsPROTEIN SCIENCE, Issue 4 2003Noelle Potier Abstract Nondenaturing electrospray mass spectrometry (ESI-MS) has been used to reveal the presence of potential ligands in the ligand-binding domain (LBD) of orphan nuclear receptors. This new approach, based on supramolecular mass spectrometry, allowed the detection and identification of fortuitous ligands for the retinoic acid-related orphan receptor , (ROR,) and the ultraspiracle protein (USP). These fortuitous ligands were specifically captured from the host cell with the proper stoichiometry. After organic extraction, these molecules have been characterized by classic analytical methods and identified as stearic acid for ROR, and a phosphatidylethanolamine (PE) for USP, as confirmed by crystallography. These molecules act as "fillers" and may not be the physiological ligands, but they prove to be essential to stabilize the active conformation of the LBD, enabling its crystallization. The resulting crystal structures provide a detailed picture of the ligand-binding pocket, allowing the design of highly specific synthetic ligands that can be used to characterize the function of orphan nuclear receptors. An additional advantage of this new method is that it is not based on a functional test and that it can detect low-affinity ligands. [source] Semi-online nanoflow liquid chromatography/matrix-assisted laser desorption ionization mass spectrometry of synthetic polymers using an octadecylsilyl-modified monolithic silica capillary columnRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2010Takehiro Watanabe We have designed a semi-online liquid chromatography/matrix-assisted laser desorption/ionization mass spectrometry (LC/MALDI-MS) system to introduce eluent from a octadecylsilyl (ODS) group modified monolithic silica capillary chromatographic column directly onto a sample plate for MALDI-MS analysis. Our novel semi-online system is useful for rapidly and sensitively examining the performance of a monolithic capillary column. An additional advantage is the small elution volume of a monolithic capillary column, which allows delicate eluents, such as 1,1,1,3,3,3,-hexafluoroisopropyl alcohol (HFIP), to be used to achieve cost-effective analysis. Using the semi-online LC/MALDI-MS system, chromatographic separation of polymers by the monolithic column with different eluents was studied. Separation of poly(methyl methacrylate) and Nylon 6/6 showed that the column functioned via size-exclusion separation when tetrahydrofuran or HFIP eluent was used. On the other hand, the separation behavior of Nylon 11 indicated a reversed-phase mode owing to the interaction of the polymer with the modified ODS group in the column. Using tetrahydrofuran/methanol (1:1, v/v) as the eluent, the LC/MALDI-MS spectra of poly(lactic acid), which contains both linear and cyclic polymer structures, showed that the column could separate the hydrophobic cyclic polymer and elute it out relatively slowly. The monolithic column functions basically via size-exclusion separation; the reversed-phase separation by interaction with the ODS functions may have less influence on column separation. The semi-online monolithic capillary LC/MALDI-MS method we have developed should provide a means of effectively analyzing synthetic polymers. Copyright © 2010 John Wiley & Sons, Ltd. [source] THE ESSENTIAL AND THE ACCIDENTALRATIO, Issue 3 2005Michael Gorman The distinction between the essential and the accidental is nearly always understood in modal terms. After criticizing some recent writings by Kit Fine that question that understanding, I develop a theory according to which whether a given feature of a thing is essential turns on whether it is explained by other features of that thing. The theory differs from the modal view by leaving room for features that are accidental even though their bearers cannot exist without them. The theory has the additional advantage of being open to the results of scientific theory. [source] Virtual reality simulators: Current status in acquisition and assessment of surgical skillsANZ JOURNAL OF SURGERY, Issue 1 2002Peter H. Cosman Medical technology is currently evolving so rapidly that its impact cannot be analysed. Robotics and telesurgery loom on the horizon, and the technology used to drive these advances has serendipitous side-effects for the education and training arena. The graphical and haptic interfaces used to provide remote feedback to the operator , by passing control to a computer , may be used to generate simulations of the operative environment that are useful for training candidates in surgical procedures. One additional advantage is that the metrics calculated inherently in the controlling software in order to run the simulation may be used to provide performance feedback to individual trainees and mentors. New interfaces will be required to undergo evaluation of the simulation fidelity before being deemed acceptable. The potential benefits fall into one of two general categories: those benefits related to skill acquisition, and those related to skill assessment. The educational value of the simulation will require assessment, and comparison to currently available methods of training in any given procedure. It is also necessary to determine , by repeated trials , whether a given simulation actually measures the performance parameters it purports to measure. This trains the spotlight on what constitutes good surgical skill, and how it is to be objectively measured. Early results suggest that virtual reality simulators have an important role to play in this aspect of surgical training. [source] | ||||||||||||||||||||||||||||