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Distinct Advantages (distinct + advantage)
Selected AbstractsChemInform Abstract: Distinct Advantage of the in situ Generation of Quaternary Ammonium Fluorides under Phase-Transfer Conditions Toward Catalytic Asymmetric Synthesis.CHEMINFORM, Issue 34 2001Takashi Ooi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] The effect of discordance among violence and general recidivism risk estimates on predictive accuracyCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 3 2006Jeremy F. Mills Introduction,Previous research has shown that the prediction of short-term inpatient violence is negatively affected when clinicians' inter-rater agreement is low and when confidence in the estimate of risk is low. This study examined the effect of discordance between risk assessment instruments used to predict long-term general and violence risk in offenders. Methods,The Psychopathy Checklist , Revised (PCL,R), Level of Service Inventory , Revised (LSI,R), Violence Risk Appraisal Guide (VRAG), and the General Statistical Information on Recidivism (GSIR) were the four risk-prediction instruments used to predict post-release general and violent recidivism within a sample of 209 offenders. Results,The findings lend empirical support to the assumption that predictive accuracy is threatened where there is discordance between risk estimates. Discordance between instruments had the impact of reducing predictive accuracy for all instruments except the GSIR. Further, the influence of discordance was shown to be greater on certain instruments over others. Discordance had a moderating effect on both the PCL,R and LSI,R but not on the VRAG and GSIR. Conclusions,There is a distinct advantage when attempting to predict recidivism to employing measures such as the LSI-R, which includes dynamic variables and intervention-related criminogenic domains, over a measure purely of fixed characteristics, such as the GSIR; however, if there is discordance between the risk estimates, caution should be exercised and more reliance on the more static historically based instrument may be indicated. Copyright © 2006 John Wiley & Sons, Ltd. [source] Treatment of Facial Telangiectasia With Variable-Pulse High-Fluence Pulsed-Dye Laser: Comparison of Efficacy with Fluences Immediately Above and Below the Purpura ThresholdDERMATOLOGIC SURGERY, Issue 7 2003Murad Alam MD Background. Pulsed-dye laser treatment has been shown to be highly effective for the treatment of facial telangiectasia. Posttreatment purpura after such treatment has limited patient acceptance of the procedure. Objective. To determine whether purpura-free treatment with recently introduced variable-pulsed pulsed-dye lasers can effectively reduce facial telangiectasia. Methods. This was a prospective, randomized, controlled, nonblinded trial. Eleven patients received variable-pulse pulsed-dye laser treatment with and without induction of purpura. Telangiectasia were graded on a "telangiectasia density scale," on which a 1 signified extremely fine, sparsely distributed telangiectasia, and 5 referred to thick, ropelike telangiectasia covering the affected area. For each subject, two areas on either side of the facial midline with equivalent telangiectasia density ratings were randomized to the purpura and purpura-free treatment groups, respectively. All treatments used a 7-mm spot size and a 10-ms pulse duration. The fluence associated with the purpura threshold for each patient was determined in test areas. Purpura-free treatment entailed a fluence 1.0 J/cm2 less than the purpura threshold, and purpura-level treatment entailed a fluence 0.5 J/cm2 greater than the threshold. Results. Six weeks after a single purpura-free treatment, mean telangiectasia ratings were reduced from 2.7 to 2.4. Purpura-level treatments resulted in a decrease to 1.4 from the same baseline. Thicker, denser telangiectasia appeared to benefit more from purpura-level treatment (a mean telangiectasia density scale reduction of 1.7) than finer, sparser telangiectasia (a mean reduction of 0.8). In 81% of cases, both investigators and patients rated the side treated with purpura as undergoing a greater reduction in telangiectasia density. Conclusion. Although facial telangiectasia do improve after a single purpura-free treatment with the variable-pulse pulsed-dye laser, they improve more after purpura is induced. Purpura-free and purpura-level treatments may be close to equivalent for treating fine telangiectasia, but purpura-level treatments have a distinct advantage for treating thicker telangiectasia. Significantly, the variable-pulse pulsed-dye laser offers patients the option of effective treatment of some telangiectasia without bruising. [source] Logging effects on sediment flux observed in a pollen-based record of overbank deposition in a northern California catchmentEARTH SURFACE PROCESSES AND LANDFORMS, Issue 7 2005José A. Constantine Abstract A palynological approach was used to estimate overbank deposition rates in a forested catchment affected by logging. The palynological approach uses downcore variations in total fossil pollen and fossil pollen assemblage to calculate rates of overbank deposition and has a distinct advantage over radioisotopic approaches in that it is not limited by radioactive decay. Using this approach, we determined that overbank deposition rates increased over 400 per cent within years of logging events and that the increased rates persisted for less than 4 years. After logging-induced deposition peaked, overbank deposition decreased over 60 per cent relative to the pre-logging background values. The decreased deposition rates persisted for over 40 years. The immediate effect of logging in this catchment was to induce mass-wasting events in hollows that produced rapidly travelling sediment pulses. In the subsequent recovery period, reduced sediment loading occurred as a result of a reduction in the volume of sediment available for transport. The reduction in sediment load led to a reduction in overbank deposition rates until subsequent logging disturbances destabilized and emptied other hollows. Copyright © 2005 John Wiley & Sons, Ltd. [source] Tracing energy flow in stream food webs using stable isotopes of hydrogenFRESHWATER BIOLOGY, Issue 5 2010JACQUES C. FINLAY Summary 1. Use of the natural ratios of carbon and nitrogen stable isotopes as tracers of trophic interactions has some clear advantages over alternative methods for food web analyses, yet is limited to situations where organic materials of interest have adequate isotopic separation between potential sources. This constrains the use of natural abundance stable isotope approaches to a subset of ecosystems with biogeochemical conditions favourable to source separation. 2. Recent studies suggest that stable hydrogen isotopes (,D) could provide a robust tracer to distinguish contributions of aquatic and terrestrial production in food webs, but variation in ,D of consumers and their organic food sources are poorly known. To explore the utility of the stable hydrogen isotope approach, we examined variation in ,D in stream food webs in a forested catchment where variation in ,13C has been described previously. 3. Although algal ,D varied by taxa and, to a small degree, between sites, we found consistent and clear separation (by an average of 67,) from terrestrial carbon sources. Environmental conditions known to affect algal ,13C, such as water velocity and stream productivity did not greatly influence algal ,D, and there was no evidence of seasonal variation. In contrast, algal ,13C was strongly affected by environmental factors both within and across sites, was seasonally variable at all sites, and partially overlapped with terrestrial ,13C in all streams with catchment areas larger than 10 km2. 4. While knowledge of isotopic exchange with water and trophic fractionation of ,D for aquatic consumers is limited, consistent source separation in streams suggests that ,D may provide a complementary food web tracer to ,13C in aquatic food webs. Lack of significant seasonal or spatial variation in ,D is a distinct advantage over ,13C for applications in many aquatic ecosystems. [source] A Bayesian approach to estimating tectonic stress from seismological dataGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2007Richard Arnold SUMMARY Earthquakes are conspicuous manifestations of tectonic stress, but the non-linear relationships between the stresses acting on a fault plane, its frictional slip, and the ensuing seismic radiation are such that a single earthquake by itself provides little information about the ambient state of stress. Moreover, observational uncertainties and inherent ambiguities in the nodal planes of earthquake focal mechanisms preclude straightforward inferences about stress being drawn on the basis of individual focal mechanism observations. However, by assuming that each earthquake in a small volume of the crust represents a single, uniform state of stress, the combined constraints imposed on that stress by a suite of focal mechanism observations can be estimated. Here, we outline a probabilistic (Bayesian) technique for estimating tectonic stress directions from primary seismological observations. The Bayesian formulation combines a geologically motivated prior model of the state of stress with an observation model that implements the physical relationship between the stresses acting on a fault and the resultant seismological observation. We show our Bayesian formulation to be equivalent to a well-known analytical solution for a single, errorless focal mechanism observation. The new approach has the distinct advantage, however, of including (1) multiple earthquakes, (2) fault plane ambiguities, (3) observational errors and (4) any prior knowledge of the stress field. Our approach, while computationally demanding in some cases, is intended to yield reliable tectonic stress estimates that can be confidently compared with other tectonic parameters, such as seismic anisotropy and geodetic strain rate observations, and used to investigate spatial and temporal variations in stress associated with major faults and coseismic stress perturbations. [source] Fluid,solid interaction problems with thermal convection using the immersed element-free Galerkin methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2010Claudio M. Pita Abstract In this work, the immersed element-free Galerkin method (IEFGM) is proposed for the solution of fluid,structure interaction (FSI) problems. In this technique, the FSI is represented as a volumetric force in the momentum equations. In IEFGM, a Lagrangian solid domain moves on top of an Eulerian fluid domain that spans over the entire computational region. The fluid domain is modeled using the finite element method and the solid domain is modeled using the element-free Galerkin method. The continuity between the solid and fluid domains is satisfied by means of a local approximation, in the vicinity of the solid domain, of the velocity field and the FSI force. Such an approximation is achieved using the moving least-squares technique. The method was applied to simulate the motion of a deformable disk moving in a viscous fluid due to the action of the gravitational force and the thermal convection of the fluid. An analysis of the main factors affecting the shape and trajectory of the solid body is presented. The method shows a distinct advantage for simulating FSI problems with highly deformable solids. Copyright © 2009 John Wiley & Sons, Ltd. [source] Highly accurate solutions of the bifurcation structure of mixed-convection heat transfer using spectral methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 5 2002M. Selmi Abstract This paper is concerned with producing highly accurate solution and bifurcation structure using the pseudo-spectral method for the two-dimensional pressure-driven flow through a horizontal duct of a square cross-section that is heated by a uniform flux in the axial direction with a uniform temperature on the periphery. Two approaches are presented. In one approach, the streamwise vorticity, streamwise momentum and energy equations are solved for the stream function, axial velocity, and temperature. In the second approach, the streamwise vorticity and a combination of the energy and momentum equations are solved for stream function and temperature only. While the second approach solves less number of equations than the first approach, a grid sensitivity analysis has shown no distinct advantage of one method over the other. The overall solution structure composed of two symmetric and four asymmetric branches in the range of Grashof number (Gr) of 0,2 × 106 for a Prandtl number (Pr) of 0.73 has been computed using the first approach. The computed structure is comparable to that found by Nandakumar and Weinitschke (1991) using a finite difference scheme for Grashof numbers in the range of 0,1×106. The stability properties of some solution branches; however, are different. In particular, the two-cell structure of the isolated symmetric branch that has been found to be unstable by the study of Nandakumar and Weinitschke is found to be stable by the current study. Copyright © 2002 John Wiley & Sons, Ltd. [source] Multiparameter models for performance analysis of UASB reactorsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2008C M Narayanan Abstract BACKGROUND: UASB (upflow anaerobic sludge blanket) bioreactors have the distinct advantage that they do not demand support particles and provide a high rate of bioconversion even with high strength feedstocks. Although apparently simple in construction, the performance analysis of these reactors involves a high degree of mathematical complexity. Most simulation models reported in the literature are rudimentary in nature as they involve gross approximations. In the present paper, two multiparameter simulation packages are presented that make no simplifying assumptions and hence are more rigorous in nature. RESULTS: The first package assumes the sludge bed to be a plug-flow reactor (PFR) and the sludge blanket to be an ideal continuous stirred tank reactor (CSTR). The second package equates the reactor to a plug flow dispersion reactor (PFDR), the axial dispersion coefficient however being a function of axial distance. The three phase nature of the sludge blanket has been considered and the variation of gas velocity in the axial direction has been taken into account. Three different kinetic equations have been considered. Resistance to diffusion of substrate into sludge granules has been accounted for by incorporating appropriately defined effectiveness factors. The applicability of simulation packages developed has been ascertained by comparing with real-life data collected from industrial/pilot plant/laboratory UASB reactors. The maximum deviation observed is ± 15%. CONCLUSIONS: Although the software packages developed have high computational load, their applicability has been successfully ascertained and they may be recommended for design and installation of industrial UASB reactors and also for the rating of existing installations. Copyright © 2008 Society of Chemical Industry [source] Transobturator tape (TOT): Two years follow-up,NEUROUROLOGY AND URODYNAMICS, Issue 1 2007Saad Juma Abstract Aims The aim of this study is to report the functional results, patient satisfaction, and morbidity of the Transobturator tape procedure (TOT) in the treatment of stress incontinence (SUI). Methods One hundred and thirty patients were prospectively evaluated with history, physical examination, quality of life questionnaire including Incontinence Impact Questionnaire (IIQ), urogenital distress inventory (UDI), and analog global satisfaction scale (GSS), and urodynamic studies. Results One hundred and seventeen patients (90%) had history of SUI, and 78 (60%) had urge incontinence. Pads/day (PPD) used was 2.48,±,2.42, and the score of IIQ 16.13,±,7.86, UDI 10.95,±,3.4, and GSS 1.41,±,1.67. All patients underwent TOT using the ObTapeÔ. Hospital stay was 0.84,±,0.76 days and catheter duration was 1.42,±,2.08 days. At a follow-up of 16.85,±, 4.68 months, 13 patients (10%) have recurrent SUI, 21 (16.15%) persistent urge incontinence, and 1 (1.92%) de novo urge incontinence. The mean PPD is 0.15,±,0.56, IIQ 1.47,±,5.14, UDI 3.28,±,3.09, and GSS 8.29,±,1.64. Two patients (1.52%) developed urethral obstruction, five (3.84%) had vaginal extrusion of the tape, and two (1.52%) had intra-operative bladder perforation. Conclusions These results demonstrate the safety and efficacy of the TOT. The short hospitalization and catheterization, low incidence of de novo urge incontinence and obstructive voiding offers a distinct advantage over existing techniques. No significant difference in outcome between patients with VLPP ,60 cm H2O, and patients with VLPP >60 cm H2O was observed. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. [source] Synthesis of new superhydrophobic nanosilica and investigation of their performance in reinforcement of polysiloxanePOLYMER COMPOSITES, Issue 9 2010XianLi Fang We reported a new facile method to synthesize superhydrophobic nanosilica using glycidoxypropyltrimethoxysilane and dodecylamine as treatment agents. Also, we systemically investigate their performance in reinforcement of poly(dimethylsiloxane) (PDMS) rubber. Fourier transform infrared spectrum, contact angle (CA) and thermogravimetric analysis (TGA) measurements were used to characterize the modified nanosilica. Results show that the inherent hydrophilicity of parent nanosilica surface can be greatly altered through this modification method. The CA of as-prepared superhydrophobic nanosilica can reach 160.2°. The properties of as-prepared modified nanosilica-filled PDMS composites were systemically investigated by dynamic rheological test, scanning electron microscopy, TGA, dynamic mechanical analysis. These as-prepared superhydrophobic nanosilica exhibit uniform dispersion in the PDMS matrix, and their composites also show good mechanical properties and distinct advantage on thermal stability compared with those of the pure silica-filled PDMS composites. Also described is the probable mechanism for the reinforcement of as-prepared superhydrophobic nanosilica-filled PDMS. POLYM. COMPOS., 31:1628,1636, 2010. © 2009 Society of Plastics Engineers [source] Powered Liposuction: An Evaluation of Currently Available InstrumentationDERMATOLOGIC SURGERY, Issue 5 2002Timothy Corcoran Flynn MD background. Over the past several years, powered liposuction instruments have become available to the dermatologic surgeon. These instruments all move the cannula forward and backward 2,12 mm with rapidity. This motion simulates the standard human movement of the cannula and facilitates movement through the tissue. Powered liposuction may help to prevent surgeon fatigue and has recently been shown to aid in the efficacy of fat removal. objective. To compare and contrast currently available powered liposuction instruments, to obtain objective engineering data on the instruments, and to compare the instruments when used on actual liposuction cases. methods. Five currently available powered liposuction systems were evaluated by the author. Each instrument was used with a 3 mm dual side port cannula on patients undergoing tumescent liposuction. An independent engineering firm, who collected objective measurements such as weight, stroke force, temperature, and vibration measurements on the instruments, evaluated the units. Noise measurements were obtained. results. Each of the five systems showed advantages and disadvantages. Important issues were the size and weight of the units, as well as whether they were driven electrically or pneumatically. Stroke force is variable (range 9.5,30 pounds). The noise of the units ranged between 60 and 87 dB. Vibration measurements varied from instrument to instrument. Units produced a variable amount of heat ranging from 77°F to 102°F. Most instruments are autoclavable, and one system is disposable. Build quality and reliability varied with the instrument. conclusion. Instruments for powered liposuction have emerged in the last 2 years, with each instrument having distinct advantages and disadvantages. This article reviews five currently available powered liposuction instruments and presents objective measurements as well as the author's experience using the instruments. [source] Therapeutic angiogenesis and vasculogenesis for tissue regenerationEXPERIMENTAL PHYSIOLOGY, Issue 3 2005Paolo Madeddu Therapeutic angiogenesis/vasculogenesis holds promise for the cure of ischaemic disease. The approach postulates the manipulation of spontaneous healing response by supplementation of growth factors or transplantation of vascular progenitor cells. These supplements are intended to foster the formation of arterial collaterals and promote the regeneration of damaged tissues. Angiogenic factors are generally delivered in the form of recombinant proteins or by gene transfer using viral vectors. In addition, new non-viral methods are gaining importance for their safer profile. The association of growth factors with different biological activity might offer distinct advantages in terms of efficacy, yet combined approaches require further optimization. Alternatively, substances with pleiotropic activity might be considered, by virtue of their ability to target multiple mechanisms. For instance, some angiogenic factors not only stimulate the growth of arterioles and capillaries, but also inhibit vascular destabilization triggered by metabolic and oxidative stress. Transplantation of endothelial progenitor cells was recently proposed for the treatment of peripheral and myocardial ischaemia. Progenitor cells can be transplanted either without any preliminary conditioning or after ex vivo genetic manipulation. Delivery of genetically modified progenitor cells eliminates the drawback of immune response against viral vectors and makes feasible repeating the therapeutic procedure in case of injury recurrence. It is envisioned that these new approaches of regenerative medicine will open unprecedented opportunities for the care of life-threatening diseases. [source] Parallel multipole implementation of the generalized Helmholtz decomposition for solving viscous flow problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2003Mary J. Brown Abstract The evaluation of a domain integral is the dominant bottleneck in the numerical solution of viscous flow problems by vorticity methods, which otherwise demonstrate distinct advantages over primitive variable methods. By applying a Barnes,Hut multipole acceleration technique, the operation count for the integration is reduced from O(N2) to O(NlogN), while the memory requirements are reduced from O(N2) to O(N). The algorithmic parameters that are necessary to achieve such scaling are described. The parallelization of the algorithm is crucial if the method is to be applied to realistic problems. A parallelization procedure which achieves almost perfect scaling is shown. Finally, numerical experiments on a driven cavity benchmark problem are performed. The actual increase in performance and reduction in storage requirements match theoretical predictions well, and the scalability of the procedure is very good. Copyright © 2003 John Wiley Sons, Ltd. [source] Interpreting variability in global SST data using independent component analysis and principal component analysisINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2010Seth Westra Abstract Component extraction techniques are used widely in the analysis and interpretation of high-dimensional climate datasets such as global sea surface temperatures (SSTs). Principal component analysis (PCA), a frequently used component extraction technique, provides an orthogonal representation of the multivariate dataset and maximizes the variance explained by successive components. A disadvantage of PCA, however, is that the interpretability of the second and higher components may be limited. For this reason, a Varimax rotation is often applied to the PCA solution to enhance the interpretability of the components by maximizing a simple structure. An alternative rotational approach is known as independent component analysis (ICA), which finds a set of underlying ,source signals' which drive the multivariate ,mixed' dataset. Here we compare the capacity of PCA, the Varimax rotation and ICA in explaining climate variability present in globally distributed SST anomaly (SSTA) data. We find that phenomena which are global in extent, such as the global warming trend and the El Niño-Southern Oscillation (ENSO), are well represented using PCA. In contrast, the Varimax rotation provides distinct advantages in interpreting more localized phenomena such as variability in the tropical Atlantic. Finally, our analysis suggests that the interpretability of independent components (ICs) appears to be low. This does not diminish the statistical advantages of deriving components that are mutually independent, with potential applications ranging from synthetically generating multivariate datasets, developing statistical forecasts, and reconstructing spatial datasets from patchy observations at multiple point locations. Copyright © 2009 Royal Meteorological Society [source] Bayesian semiparametric estimation of discrete duration models: an application of the dirichlet process priorJOURNAL OF APPLIED ECONOMETRICS, Issue 1 2001Michele Campolieti This paper proposes a Bayesian estimator for a discrete time duration model which incorporates a non-parametric specification of the unobserved heterogeneity distribution, through the use of a Dirichlet process prior. This estimator offers distinct advantages over the Nonparametric Maximum Likelihood estimator of this model. First, it allows for exact finite sample inference. Second, it is easily estimated and mixed with flexible specifications of the baseline hazard. An application of the model to employment duration data from the Canadian province of New Brunswick is provided. Copyright © 2001 John Wiley & Sons, Ltd. [source] A new approach for detecting scientific specialties from raw cocitation networksJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 2 2009Matthew L. Wallace We use a technique recently developed by V. Blondel, J.-L. Guillaume, R. Lambiotte, and E. Lefebvre (2008) to detect scientific specialties from author cocitation networks. This algorithm has distinct advantages over most previous methods used to obtain cocitation "clusters" since it avoids the use of similarity measures, relies entirely on the topology of the weighted network, and can be applied to relatively large networks. Most importantly, it requires no subjective interpretation of the cocitation data or of the communities found. Using two examples, we show that the resulting specialties are the smallest coherent "groups" of researchers (within a hierarchy of cluster sizes) and can thus be identified unambiguously. Furthermore, we confirm that these communities are indeed representative of what we know about the structure of a given scientific discipline and that as specialties, they can be accurately characterized by a few keywords (from the publication titles). We argue that this robust and efficient algorithm is particularly well-suited to cocitation networks and that the results generated can be of great use to researchers studying various facets of the structure and evolution of science. [source] Continuous Glucose Monitoring in Dogs and CatsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2008C.E. Wiedmeyer Use of continuous glucose monitoring in veterinary medicine is gaining popularity. Through use of a commercially available continuous glucose monitor system, insights into daily glucose changes in dogs and cats are achievable. The continuous glucose monitoring system measures glucose concentrations in the interstitial fluid of the subcutaneous space by use of a small, flexible probe. When placed in the subcutaneous tissue, the probe is connected to a recording device that is attached to the animal and records the interstitial fluid glucose concentration every 5 minutes (288 readings per 24 hours). Once attached and properly calibrated, the instrument can remain in place for several days, hospitalization of the patient is not necessary, and the normal daily routine of the animal can be maintained. The data from the recording device are then downloaded and a very detailed picture of the interstitial fluid glucose concentration over that time period can be obtained. Subcutaneous interstitial fluid glucose concentrations have a good correlation to blood glucose concentrations within a defined range. The continuous glucose monitoring system has distinct advantages over traditional blood glucose curves and is a valuable tool for managing diabetic dogs and cats. In addition, other clinical uses for continuous glucose monitoring are being developed. This review is designed to outline the technology behind the continuous glucose monitoring system, describe the clinical use of the instrument, provide clinical examples in which it may be useful, and discuss future directions for continuous glucose monitoring in dogs and cats. [source] Role of circulating neurotoxins in the pathogenesis of hepatic encephalopathy: potential for improvement following their removal by liver assist devicesLIVER INTERNATIONAL, Issue 2003Roger F. Butterworth Abstract Both acute and chronic liver failure result in impaired cerebral function known as hepatic encephalopathy (HE). Evidence suggests that HE is the consequence of the accumulation in brain of neurotoxic and/or neuroactive substance including ammonia, manganese, aromatic amino acids, mercaptans, phenols, short-chain fatty acids, bilirubin and a variety of neuroactive medications prescribed as sedatives to patients with liver failure. Brain ammonia concentrations may attain levels in excess of 2 mm, concentrations which are known to adversely affect both excitatory and inhibitory neurotransmission as well as brain energy metabolism. Manganese exerts toxic effects on dopaminergic neurones. Prevention and treatment of HE continues to rely heavily on the reduction of circulating ammonia either by reduction of gut production using lactulose or antibiotics or by increasing its metabolism using l -ornithine- l -aspartate. No specific therapies have so far been designed to reduce circulating concentrations of other toxins. Liver assist devices offer a potential new approach to the reduction of circulating neurotoxins generated in liver failure. In this regard, the Molecular Absorbents Recirculating System (MARS) appears to offer distinct advantages over hepatocyte-based systems. [source] Do open-ended survey questions on migration motives create coder variability problems?POPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 1 2009Thomas Niedomysl Abstract Contemporary research on migration has benefited from adopting a variety of methodological approaches and different sources of information to provide answers to the ever-recurring question of why people migrate. Yet, when it comes to central methods used for researching migration motives, progress appears to have been slow. This paper focuses on surveys to research migration motives using self-administered postal questionnaires. It addresses a key validity question, namely the issue of whether the usage of open-ended questions creates coder variability problems. An experimental research design was used where five coders independently coded 500 randomly selected responses from a large survey on migration motives. Krippendorff's , was calculated to test the level of agreement between the coders. The results advance our knowledge in two important ways: firstly, it is shown that coder variability is not a major problem (Krippendorff's , = 0.82). Secondly, it identifies those types of responses that nevertheless appear problematic to code. The implications of these findings for survey research on migration motives are discussed, and it is argued that open-ended questions have some distinct advantages compared with the more commonly used closed-ended questions. Copyright © 2009 John Wiley & Sons, Ltd. [source] Restorative Justice , Is More Better?THE HOWARD JOURNAL OF CRIMINAL JUSTICE, Issue 5 2004The Experience of Police-led Restorative Cautioning Pilots in Northern Ireland This article describes how two police-led restorative cautioning pilots for juveniles operated in Northern Ireland. The pilots were found to offer a number of distinct advantages over the traditional cautioning practice and helped secure some of the values of restorative justice. However, they were not without fault and the research found evidence of ,net-widening', whereby some offenders appeared to have been drawn into the schemes unnecessarily. It was also evident that the schemes required significant resources in order to involve participants (particularly victims) and to operate effectively. In light of the government's intention to greatly expand restorative practice in Northern Ireland generally, this article argues for the need to do so with care, if the quality of restorative justice is not to be compromised. [source] Validation of salivary cortisol and testosterone assays in chimpanzees by liquid chromatography-tandem mass spectrometryAMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2009Nobuyuki Kutsukake Abstract Owing to its high temporal sensitivity, saliva has distinct advantages for measuring steroids, compared with other noninvasive samples such as urine and feces. Here, we report the validity of assaying salivary cortisol (C) and testosterone (T) using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in captive male chimpanzees, Pan troglodytes. For both the C and T concentrations, we found positive relationships between saliva and plasma. The concentrations of C and T in saliva showed clear patterns of diurnal fluctuation, whereas those in urine and feces did not. These results suggest that the salivary steroid concentrations can be regarded as good indicators of circulating steroid levels. We also developed and validated an efficient method for collecting saliva samples from cotton rope. Although rope includes inherent steroid-like compounds and may affect the accuracy of steroid measurements, our rope-washing procedures effectively removed intrinsic steroidal materials. There was a significant association between the C and T concentrations measured from saliva collected from rope licked by the chimpanzees and those measured from saliva collected directly from the mouth. Salivary T values estimated by LC/MS-MS were similar to those measured by radioimmunoassay. The results indicate the usefulness of saliva as a noninvasive steroid measure and that steroids in the saliva of chimpanzees can be accurately measured by LC-MS/MS. Am. J. Primatol. 71:696,706, 2009. © 2009 Wiley-Liss, Inc. [source] The Diamedica Draw-Over Vaporizer: a comparison of a new vaporizer with the Oxford Miniature VaporizerANAESTHESIA, Issue 1 2009W. A. English Summary The Diamedica Draw-Over Vaporizer (DDV) has been developed as an alternative to the Oxford Miniature Vaporizer (OMV). Both can function as draw-over or plenum vaporizers. The performances of these two vaporizers were compared under conditions simulating intermittent positive pressure ventilation (IPPV) and continuous flow (CF). Series 1 experiments were conducted with the vaporizers in water baths at 20, 25 and 30 °C. Vaporizers were tested at dial settings of 1,4% over a range of minute volumes (1.75,6 l.min,1) and flow rates (3,8 l.min,1). Series 2 experiments compared output of the vaporizers over time at ambient temperatures of 20, 25 and 30 °C. A minute volume of 6 l.min,1 (IPPV) and a gas flow of 8 l.min,1 (CF) were used with a vaporizer setting of 2%. Vapour concentrations were recorded at 5-min intervals. In series 1 IPPV experiments, the DDV vaporizer was more accurate, producing significantly fewer vapour concentrations 0.5% more than or less than setting (p = 0.013). The OMV tended to produce more favourable results under continuous flow (p = 0.42). In series 2 experiments, the accuracy of both vaporizers was similar but consistency of output over time was better for the DDV and consistency of output according to differences in ambient temperature was better for the DDV. The OMV produced more vapour concentrations that were markedly higher than dial setting, particularly at high ambient temperatures. The DDV is a suitable alternative to the OMV with some distinct advantages. These include a larger reservoir, tendency towards greater accuracy during IPPV and improved consistency of output. [source] Vascular closure staples reduce intimal hyperplasia in prosthesis implantationANZ JOURNAL OF SURGERY, Issue 12 2002Wayne J. Hawthorne Background: Vascular surgery, like the various other surgical specialities, has seen an increasing demand toward faster and more minimally invasive procedures. One such need is to create a reliable vascular anastomosis that is faster, easier and less damaging to the tissue. The vascular closure staples (VCS*) device provides such characteristics but, to date, no studies have investigated its effectiveness in reducing intimal hyperplasia when used for vascular prosthesis implantation. The present study evaluated its effectiveness compared with suturing of a graft in vascular prosthesis implantation. Methods: Twelve female Merino sheep underwent gelatin sealed Dacron patch graft implantation into the left and right common carotid artery. Grafts were randomly allocated so that one carotid artery and graft was anastomosed using sutures and the other with VCS*. The two techniques were compared for operation time, clip/suture numbers and blood loss during the implantation procedure. After a 4-week period, the sheep were killed and the grafts were harvested for intimal hyperplasia (IH) assessment. Results: There was a significant reduction in the amount of IH seen in the VCS* group (mean ± SD: 0.278 ± 0.079 mm2/mm) when compared with the sutured group (0.575 ± 0.331 mm2/mm) (P < 0.05). There was also significant reduction in anastomosis time (mean ± SD: 14 ± 4.4 min) and fewer points of contact (23 ± 1.4) using the VCS* compared with suturing (22 ± 3.2 min, P < 0.01; 27 ± 3.3, P < 0.05, respectively). Conclusions: In this model, the VCS* shows several distinct advantages over suturing with significant time saving at operation and, most importantly, the reduction of IH seen at 1 month. [source] Low-resolution remotely sensed images of winegrape vineyards map spatial variability in planimetric canopy area instead of leaf area indexAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2008A. HALL Abstract Background and Aims:, Knowledge of the spatial variability of grapevine canopy density is useful in managing the variability of grape composition and yield. Rapid assessment of the characteristics of vineyards by remote sensing offers distinct advantages over ground-based measurements. In an effort to capture such advantages, this study aimed to assess the relative contribution to LAI of grapevine canopy density and grapevine canopy area derived from high-spatial-resolution airborne digital imagery. Methods and Results:, High-spatial-resolution airborne NDVI imagery of minimally pruned, unconfined (i.e. not confined by trellising) grapevines was used to partition image pixels into grapevine-only and non-grapevine groupings. An evaluation of the relative contributions of grapevine planimetric area (number of grapevine pixels across a single row) and leaf layers (NDVI of grapevine-only pixels) found that the variability observed across the vineyard was dominated by changes in canopy area rather than grapevine-only NDVI. Conclusion:, The primary predictive variable of grapevine LAI is canopy area. Low-spatial-resolution NDVI imagery of minimally pruned, unconfined vineyards is therefore effective in mapping spatial variability in planimetric canopy area, rather than LAI. Significance of the Study:, The process of estimating grapevine LAI from mixed pixels has incorrectly assumed that both components of LAI within a pixel's footprint, namely the number of leaf layers and planimetric canopy area, produce a consistent response in NDVI. Correlations between NDVI and LAI reported in previous studies based on low-resolution imagery most likely relied on the proxy relationship between NDVI and canopy area. [source] Microfluidic biolector,microfluidic bioprocess control in microtiter platesBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2010Matthias Funke Abstract In industrial-scale biotechnological processes, the active control of the pH-value combined with the controlled feeding of substrate solutions (fed-batch) is the standard strategy to cultivate both prokaryotic and eukaryotic cells. On the contrary, for small-scale cultivations, much simpler batch experiments with no process control are performed. This lack of process control often hinders researchers to scale-up and scale-down fermentation experiments, because the microbial metabolism and thereby the growth and production kinetics drastically changes depending on the cultivation strategy applied. While small-scale batches are typically performed highly parallel and in high throughput, large-scale cultivations demand sophisticated equipment for process control which is in most cases costly and difficult to handle. Currently, there is no technical system on the market that realizes simple process control in high throughput. The novel concept of a microfermentation system described in this work combines a fiber-optic online-monitoring device for microtiter plates (MTPs),the BioLector technology,together with microfluidic control of cultivation processes in volumes below 1,mL. In the microfluidic chip, a micropump is integrated to realize distinct substrate flow rates during fed-batch cultivation in microscale. Hence, a cultivation system with several distinct advantages could be established: (1) high information output on a microscale; (2) many experiments can be performed in parallel and be automated using MTPs; (3) this system is user-friendly and can easily be transferred to a disposable single-use system. This article elucidates this new concept and illustrates applications in fermentations of Escherichia coli under pH-controlled and fed-batch conditions in shaken MTPs. Biotechnol. Bioeng. 2010;107: 497,505. © 2010 Wiley Periodicals, Inc. [source] Impedance spectroscopy as a tool for non-intrusive detection of extracellular mediators in microbial fuel cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009Ramaraja P. Ramasamy Abstract Endogenously produced, diffusible redox mediators can act as electron shuttles for bacterial respiration. Accordingly, the mediators also serve a critical role in microbial fuel cells (MFCs), as they assist extracellular electron transfer from the bacteria to the anode serving as the intermediate electron sink. Electrochemical impedance spectroscopy (EIS) may be a valuable tool for evaluating the role of mediators in an operating MFC. EIS offers distinct advantages over some conventional analytical methods for the investigation of MFC systems because EIS can elucidate the electrochemical properties of various charge transfer processes in the bio-energetic pathway. Preliminary investigations of Shewanella oneidensis DSP10-based MFCs revealved that even low quantities of extracellular mediators significantly influence the impedance behavior of MFCs. EIS results also suggested that for the model MFC studied, electron transfer from the mediator to the anode may be up to 15 times faster than the electron transfer from bacteria to the mediator. When a simple carbonate membrane separated the anode and cathode chambers, the extracellular mediators were also detected at the cathode, indicating diffusion from the anode under open circuit conditions. The findings demonstrated that EIS can be used as a tool to indicate presence of extracellular redox mediators produced by microorganisms and their participation in extracellular electron shuttling. Biotechnol. Bioeng. 2009; 104: 882,891. © 2009 Wiley Periodicals, Inc. [source] Alternative haematopoietic stem cell sources for transplantation: place of umbilical cord bloodBRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2009Angela R. Smith Summary Umbilical cord blood has rapidly become a valuable alternative stem cell source for allogeneic haematopoietic stem cell transplantation. Extensive research over the last 20 years has established the safety and efficacy of umbilical cord blood transplantation in both children and adults with a variety of malignant and non-malignant diseases. This research has clearly shown that this stem cell source has several unique characteristics resulting in distinct advantages and disadvantages when compared to transplantation with unrelated bone marrow or peripheral blood stem cells. This article reviews the most recent literature comparing the outcomes after umbilical cord blood transplantation with other alternative stem cell sources. [source] Three-dimensional angiographic imaging of leakage in branch retinal vein occlusionACTA OPHTHALMOLOGICA, Issue 2 2010Ursula Margarethe Schmidt-Erfurth Abstract. Purpose:, Optical coherence tomography (OCT) is used to image branch retinal vein occlusion (BRVO) but lacks information about leakage dynamics and perfusion status. Topographical angiography (TAG) is capable of providing this information and has been described previously in age-related macular degeneration. This study evaluates TAG in BRVO. Methods:, We included 56 eyes of 40 consecutive patients with BRVO and a reduction in central vision. Two groups were established based on whether argon laser coagulation was performed or not. A standardized follow-up was performed. The chorioretinal fluorescence pattern was reconstructed following TAG. Quantitative measurements were also performed. Results:, TAG performed from indocyanine green angiography (ICGA) showed smaller lesion size (LS) compared to fluorescein angiography (FA) (mean difference: early phase = ,1.6 mm2, late phase = ,1.8 mm2). The extent of mean LS from early to late phase increased by 0.8 mm2 in FA and by 0.6 mm2 in ICGA. TAG could visualize different degrees of leakage topographically. Conclusion:, TAG gives new insights into the pathophysiology of BRVO: it enables the visualization of dynamics of leakage and the demonstration of the effects of intravasal stasis. Furthermore, TAG is less impaired by masking phenomena than FA. Functional retinal imaging shows distinct advantages over OCT: quantification of leakage activity is possible using TAG. [source] Enantioselective Organocatalytic Addition of Oxazolones to 1,1-Bis(phenylsulfonyl)ethylene: A Convenient Asymmetric Synthesis of Quaternary ,-Amino AcidsCHEMISTRY - A EUROPEAN JOURNAL, Issue 18 2010Andrea-Nekane Abstract A new, easy, and highly enantioselective method for the synthesis of quaternary ,-alkyl-,-amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1-bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords ,,,-disubstituted ,-amino acid derivatives with complete C4 regioselectivity and with excellent yields and enantioselectivities. This methodology is complementary to previously reported enantioselective approaches to quaternary ,-amino acids and allows the synthesis of ,-phenyl-,-alkyl-,-amino acids and ,- tert -butyl-,-alkyl-,-amino acids. It has distinct advantages in terms of operational simplicity, enviromentally friendly conditions, and suitability for large-scale reactions. [source] | |||||||||||||||||||||||||