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Conventional Methods (conventional + methods)
Selected AbstractsEVALUATION OF THE APPLICABILITY OF CONVENTIONAL METHODS FOR THE CHEMICAL CHARACTERIZATION OF WATERLOGGED ARCHAEOLOGICAL WOODARCHAEOMETRY, Issue 4 2010BENEDETTO PIZZO A series of 112 waterlogged archaeological wood samples of different provenances, wood species, burial times and states of preservation were analysed with the aim of assessing the validity (in terms of limits and reliability) of procedures conventionally used in the pulp and paper industry, to evaluate the state of preservation of decayed wood. In particular, the extent of any damage wrought on decayed wood tissue by the repetitive cycles that characterize these procedures was evaluated as a function of the degradation of the samples. The results indicated that standard methodologies give reliable measurements regardless of the extent of wood decay. However, it is essential to compare these data with those of non-decayed wood that has been measured using the same procedures to take account of the errors that are inherent in these methodologies and that affect measurements. [source] Hair Analysis Versus Conventional Methods of Drug Testing in Substance Abusers Seeking Organ TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2010D. L. Haller As substance abusers need to demonstrate abstinence prior to transplant, valid/reliable drug tests are needed. Patients may deny use, fearing surgery will be delayed. Breath, blood and urine tests have brief detection windows that allow patients to evade detection. Routine laboratory tests do not include all substances of abuse. Hair analysis overcomes these barriers, increasing the likelihood that active users will be identified. This study compared results for alcohol, opioids and cocaine based on 445 self-report, breath, urine and hair samples from 42 patients who had been denied a transplant due to recent substance abuse. Compared to hair toxicology, sensitivity for conventional drug tests was moderate for cocaine and opioids, but poor for alcohol. Of positive hair tests, only half were corroborated through other tests. In contrast, specificity was high across tests and substances, with positive findings from conventional tests confirmed through hair toxicology. Based on a 90-day detection window for hair analysis, two negative tests suggest 6 months of continuous abstinence. Hair testing should be considered as an alternative approach for monitoring substance use in the transplant population, either as a routine procedure or when the veracity of findings from conventional tests is in doubt. [source] A Comparative Study on the Synthesis of 3,-Aryl-3-methyl/2, 3-Dimethylspiro[6,7,8,9-tetrahydro-5H-benzo[a]cyclohepten-5, 2,-(Tetrahydro[1,3]thiazolane)]-4,-ones Using Microwave Irradiation and Conventional Methods.CHEMINFORM, Issue 42 2004Peesapati Venkateswarlu Abstract For Abstract see ChemInform Abstract in Full Text. [source] Bi-level Programming Formulation and Heuristic Solution Approach for Dynamic Traffic Signal OptimizationCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2006Dazhi Sun Conventional methods of signal timing optimization assume given traffic flow pattern, whereas traffic assignment is performed with the assumption of fixed signal timing. This study develops a bi-level programming formulation and heuristic solution approach (HSA) for dynamic traffic signal optimization in networks with time-dependent demand and stochastic route choice. In the bi-level programming model, the upper level problem represents the decision-making behavior (signal control) of the system manager, while the user travel behavior is represented at the lower level. The HSA consists of a Genetic Algorithm (GA) and a Cell Transmission Simulation (CTS) based Incremental Logit Assignment (ILA) procedure. GA is used to seek the upper level signal control variables. ILA is developed to find user optimal flow pattern at the lower level, and CTS is implemented to propagate traffic and collect real-time traffic information. The performance of the HSA is investigated in numerical applications in a sample network. These applications compare the efficiency and quality of the global optima achieved by Elitist GA and Micro GA. Furthermore, the impact of different frequencies of updating information and different population sizes of GA on system performance is analyzed. [source] Right Ventricular Function in Congenital Heart Defects Assessed by Regional Wall MotionCONGENITAL HEART DISEASE, Issue 3 2010FSCAI, Michael R. Nihill MB ABSTRACT Objectives., To develop a simple method to assess right ventricular function by angiography. Background., Conventional methods of evaluating right ventricular function are inaccurate, cumbersome, and expensive. Methods., We analyzed biplane right ventricular angiograms taken in the posterior,anterior and lateral projections using software to measure right ventricular volumes and regional wall motion in 78 patients with normal hearts (n = 29), atrial septal defects (ASD n = 13), pulmonary valve stenosis (PVS n = 21), and postoperative atrial switch patients (n = 15). We also measured the shortening fraction (SF) from the midtricuspid annulus to the septum and correlated various angiographic measurements with the right ventricular (RV) ejection fraction. Results., The volume-overloaded patients (ASD) had larger end diastolic volumes and increased SF compared with normal patients, while the pressure-loaded patients (PVS) had normal volumes and SF. The postoperative atrial switch patients had decreased systolic function and increased end diastolic volume. The SF for all of the patients correlated with the ejection fraction (r= 0.785, P, .0001). Conclusions., A simple measurement of the end diastolic and end systolic distance from the midtricuspid annulus to the septum (SF) provides a good index of RV function by angiography and correlates well with RV ejection fraction. [source] Novel application of flow cytometry: Determination of muscle fiber types and protein levels in whole murine skeletal muscles and heartCYTOSKELETON, Issue 12 2007Connie Jackaman Abstract Conventional methods for measuring proteins within muscle samples such as immunohistochemistry and western blot analysis can be time consuming, labor intensive and subject to sampling errors. We have developed flow cytometry techniques to detect proteins in whole murine heart and skeletal muscle. Flow cytometry and immunohistochemistry were performed on quadriceps and soleus muscles from male C57BL/6J, BALB/c, CBA and mdx mice. Proteins including actins, myosins, tropomyosin and ,-actinin were detected via single staining flow cytometric analysis. This correlated with immunohistochemistry using the same antibodies. Muscle fiber types could be determined by dual labeled flow cytometry for skeletal muscle actin and different myosins. This showed similar results to immunohistochemistry for I, IIA and IIB myosins. Flow cytometry of heart samples from C57BL/6J and BALB/c mice dual labeled with cardiac and skeletal muscle actin antibodies demonstrated the known increase in skeletal actin protein in BALB/c hearts. The membrane-associated proteins ,-sarcoglycan and dystrophin could be detected in C57BL/6J mice, but were decreased or absent in mdx mice. With the ability to label whole muscle samples simultaneously with multiple antibodies, flow cytometry may have advantages over conventional methods for certain applications, including assessing the efficacy of potential therapies for muscle diseases. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] Decreasing effective nanofluidic filter size by modulating electrical double layers: Separation enhancement in microfabricated nanofluidic filtersELECTROPHORESIS, Issue 23 2008Hansen Bow Abstract Conventional methods for separating biomolecules are based on steric interactions between the biomolecules and randomly oriented gel fibers. The recently developed artificial molecular sieves also rely on steric interactions for separation. In this work, we present an experimental investigation of a method that can be used in these sieves to increase separation selectivity and resolution. This method exploits the electrostatic repulsion between the charged molecules and the charged nanofluidic structure. Although this method has been mentioned in the previous work, it has not been examined in detail. We characterize this method by comparing the selectivity with that achieved in devices with different dimensions. The results of this study are relevant to the optimization of chip-based gel-free biomolecule separation and analysis. [source] Selectivity and competitive interactions between two benthic invertebrate grazers (Asellus aquaticus and Potamopyrgus antipodarum): an experimental study using 13C- and 15N-labelled diatomsFRESHWATER BIOLOGY, Issue 2 2005N. ABERLE Summary 1. Tracer experiments with two diatoms labelled with 13C (Nitzschia palea) and 15N (Fragilaria crotonensis), were conducted to investigate feeding selectivity and interspecific competition between the grazers Asellus aquaticus (Isopoda, Crustacea) and Potamopyrgus antipodarum (Hydrobiidae, Gastropoda). Conventional methods, such as cell counts and estimated biovolume, were used first to detect feeding preferences within the different grazer treatments. 2. The results revealed a significant decline in algal biovolume in all grazer treatments and no indications of active selectivity were observed. In contrast to conventional methods, measurements based on isotope signatures showed strong differences in tracer uptake, thus indicating different degrees of assimilation and digestion by the two grazers. 3. The selectivity index Q, which provides information on the uptake ratio of 13C to 15N, showed a significant time effect for both grazer species and a significant difference between single- and mixed-grazer treatments for P. antipodarum. Thus, this technique enabled the direct quantification of the uptake by grazers and, therefore, served as an ideal tool for the detection of passive selectivity. 4. Our results indicate a shift in feeding preferences related to between-species competition and a potential divergence of trophic niches when species coexist. [source] Lithology and hydrocarbon mapping from multicomponent seismic dataGEOPHYSICAL PROSPECTING, Issue 2 2010Hüseyin Özdemir ABSTRACT Elastic rock properties can be estimated from prestack seismic data using amplitude variation with offset analysis. P-wave, S-wave and density ,reflectivities', or contrasts, can be inverted from angle-band stacks. The ,reflectivities' are then inverted to absolute acoustic impedance, shear impedance and density. These rock properties can be used to map reservoir parameters through all stages of field development and production. When P-wave contrast is small, or gas clouds obscure reservoir zones, multicomponent ocean-bottom recording of converted-waves (P to S or Ps) data provides reliable mapping of reservoir boundaries. Angle-band stacks of multicomponent P-wave (Pz) and Ps data can also be inverted jointly. In this paper Aki-Richards equations are used without simplifications to invert angle-band stacks to ,reflectivities'. This enables the use of reflection seismic data beyond 30° of incident angles compared to the conventional amplitude variation with offset analysis. It, in turn, provides better shear impedance and density estimates. An important input to amplitude variation with offset analysis is the Vs/Vp ratio. Conventional methods use a constant or a time-varying Vs/Vp model. Here, a time- and space-varying model is used during the computation of the ,reflectivities'. The Vs/Vp model is generated using well log data and picked horizons. For multicomponent data applications, the latter model can also be generated from processing Vs/Vp models and available well data. Reservoir rock properties such as ,,, ,,, Poisson's ratio and bulk modulus can be computed from acoustic impedance, shear impedance and density for pore fill and lithology identification. , and , are the Lamé constants and , is density. These estimations can also be used for a more efficient log property mapping. Vp/Vs ratio or Poisson's ratio, ,, and weighted stacks, such as the one computed from ,, and ,/,, are good gas/oil and oil/water contact indicators, i.e., pore fill indicators, while ,, mainly indicates lithology. ,, is also affected by pressure changes. Results from a multicomponent data set are used to illustrate mapping of gas, oil and water saturation and lithology in a Tertiary sand/shale setting. Whilst initial log crossplot analysis suggested that pore fill discrimination may be possible, the inversion was not successful in revealing fluid effects. However, rock properties computed from acoustic impedance, shear impedance and density estimates provided good lithology indicators; pore fill identification was less successful. Neural network analysis using computed rock properties provided good indication of sand/shale distribution away from the existing wells and complemented the results depicted from individual rock property inversions. [source] Recharge, upflux and water table response for shallow water table conditions in southwest FloridaHYDROLOGICAL PROCESSES, Issue 9 2006Fouad H. Jaber Abstract A disproportionate increase or decrease in water table in response to minor water input or drainage is observed in shallow water table conditions inside drainage lysimeters. This increase happens because the capillary fringe of the shallow water table reaches up to or near the surface (Wieringermeer effect). The correlations between water table level changes and rainfall, seepage irrigation, drip irrigation, and drainage were analysed. Correlations with rainfall, seepage irrigation, and drainage were high (R2 ranged from 0·46 to 0·97). Drip irrigation had low correlations due to the low rates of application (R2 ranged from 0·26 to 0·44). Conventional methods of calculating recharge, such as multiplying the specific yield with the water table fluctuations, cannot be used for Wieringermeer effect situations. A method using water balance data and soil moisture at different depths in the lysimeters was developed to estimate recharge and upflux. The recharge results were used to develop the apparent specific yield Sya, which could be used to calculate consequent recharge events from water table fluctuation data. Combining the water table fluctuation relationships developed with the Sya value will allow the prediction of recharge from rainfall and irrigation events without the need for soil moisture equipment. Copyright © 2005 John Wiley & Sons, Ltd. [source] NONLINEAR CONSTRAINED OPTIMIZATION of THERMAL PROCESSING II.JOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2003FINITE CYLINDRICAL GEOMETRIES, VARIABLE PROCESS TEMPERATURE PROFILES to REDUCE PROCESS TIME, to IMPROVE NUTRIENT RETENTION IN SPHERICAL ABSTRACT Conventional methods for thermal processing of foods use constant processing temperature profiles (CPTPs) for a prescribed processing time, which is based on achieving a required microbial lethality to comply with public health standards. This also results in degradation of nutrients and quality factors. the variable process temperature profiles (VPTPs) obtained by using optimization methods can reduce quality losses and/or processing time compared to CPTPs. the objective of this research was to evaluate VPTPs using the Complex Method to reduce the processing time and/or improve quality retention for a specified level of lethality in thermal processing of conduction heated foods. the VPTPs were obtained for volume average retention of thiamine considering different sizes of spheres (small and large) and finite cylinders (small and large), and the thiamine retention and processing time results were compared with a conventional method (processing at 121.1C) for a specified lethality level. the use of VPTPs resulted in a 37 and 10% decrease in processing times in spherical and 40 % and 6 % for finite cylindrical shapes, for the same objective function value and specified lethality compared to the CPTP process. For the same processing time, the improvements in thiamine destruction were 3.7 and 2 % for spheres, and 3.9 and 2.2% for finite cylinders. [source] Efficacy of Pulsed UV-Light for the Decontamination of Escherichia coli O157:H7 and Salmonella spp. on Raspberries and StrawberriesJOURNAL OF FOOD SCIENCE, Issue 5 2008K.L. Bialka ABSTRACT:, Small fruits are increasingly being implicated in outbreaks of foodborne illness, and fresh produce is now the 2nd leading cause of foodborne illness in the United States. Conventional methods of decontamination are not effective, and there is a need to evaluate novel technologies. Pulsed ultraviolet (UV)-light is one such technology. In this study, pulsed UV-light was applied to strawberries and raspberries at varying UV doses and times. On raspberries, maximum reductions of Escherichia coli O157:H7 and Salmonella were 3.9 and 3.4 log10 CFU/g at 72 and 59.2 J/cm2, respectively. On the surfaces of strawberries, maximum reductions were 2.1 and 2.8 log10 CFU/g at 25.7 and 34.2 J/cm2, respectively. There was no observable damage to the fruits at these UV doses. The results obtained in this study indicate that pulsed UV-light has the potential to be used as a decontamination method for raspberries and strawberries. [source] Methods for prenatal assessment of fetal cardiac functionPRENATAL DIAGNOSIS, Issue 13 2009Tim Van Mieghem Abstract Fetal cardiac function is increasingly recognized as a marker of disease severity and prognosis in selected fetal conditions. Magnetic resonance imaging (MRI) has been used in experimental (animal) fetal cardiology but the lack of a noninvasive fetal electrocardiogram (ECG) to trigger image acquisition remains a major limiting factor precluding its application in humans. Fetal medicine specialists are therefore limited to ultrasound to evaluate human fetal cardiac function. In this review, we aim to provide a complete overview of the different ultrasound techniques that can be used for fetal cardiac function assessment and we discuss their (theoretical) strengths and shortcomings. Conventional methods include M-mode assessment of ventricular contractility and Doppler assessment of the precordial veins and cardiac output (CO). More recent techniques such as the measurement of the myocardial performance index (MPI), myocardial motion analysis with tissue Doppler, speckle tracking and three-dimensional (3D) ultrasound techniques are also discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Identification and quantitation of phenolic compounds in faecal matrix by capillary gas chromatography and nano-electrospray mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2006Ulrike Knust Very few relevant methods have been described for the detection and quantitation of phenolic compounds in faecal matrix. Extraction with conventional organic solvents such as chloroform/methanol (2:1, Folch reagent), methanol and ethanol (72%) showed high extraction efficiency for lipids and also gave good recovery of the major phenolic compounds present in the matrix. However, in comparison with a newly developed phosphate buffer method, the yield of minor phenolics was negligible when detected by these conventional methods. Conventional methods also lead to contamination of the ion source of the mass spectrometer and rapid deterioration of column performance mostly due to the high concentration of lipids. However, if the faecal matrix is initially extracted with phosphate buffer, and the extract acidified and re-extracted with diethyl ether, the range and yield of phenolic compounds are enhanced and the problem of lipid contamination is substantially alleviated. Following pilot studies and optimisation of the procedure, individual phenolic compounds (n,=,29) were identified by nano-electrospray ionisation mass spectrometry (nano-ESI-MS), nano-ESI-tandem mass spectrometry (MS/MS) and gas chromatography/mass spectrometry (GC/EI-MS) and quantitated (n,=,27) by GC/MS in subsets (n,=,5) of faecal samples, collected during the European Agency for Cancer Prevention calcium/fibre intervention study from four European countries (Italy, Germany, Spain and Denmark). A range of phenolic compounds (mainly acids) was detected, dominated by phenylacetic, benzoic, phenylpropionic and m -hydroxyphenylpropionic acids, representing on average 9.91 (93%), 8.25 (92%), 9.45 (95%) and 11.05 (98%) mM in the Italian, German, Spanish and Danish samples, respectively. The new method should enable large epidemiologic, case-control and intervention studies on the relevance of phenolic antioxidants in the aetiology of colorectal cancer to be conducted in the future. Copyright © 2006 John Wiley & Sons, Ltd. [source] Manufacture of solvent-free polylactic-glycolic acid (PLGA) scaffolds for tissue engineeringASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009Shih-Jung Liu Abstract Conventional methods for fabricating polymeric scaffolds often use organic solvents which might be harmful to cells or tissues. The purpose of this report was to develop a solvent-free method for the fabrication of three-dimensional scaffolds for tissue engineering. To manufacture a scaffold, polylactide-polyglycolide (PLGA) copolymers were premixed with sodium chloride particulates. The mixture was then compression molded and sintered to form a cylinder. After sintering, the cylinder was submerged in water for 48 h to leach out the particulates. The scaffold, with approximately 2 × 107 mesenchymal stem cells (MSCs) of the New Zealand rabbit, was then cultured in an osteogenic culture medium for 14 days. The alkaline phosphatase activity, calcium level, and the mineral deposition of cultured cells in the PLGA scaffolds were determined. The results showed that an increase of alkaline phosphatase activity and calcium levels, as well as abundant mineral deposition, was observed in the cultured mesenchymal stem cells. In addition, scaffolds with pore sizes of 88,125 µm showed the most number of cells during the period of culture. Developing solvent-free biodegradable scaffolds for bone cells may provide a potential method for the treatment of infected bone defects. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Duplexed On-Microbead Binding Assay for Competitive Inhibitor of Epidermal Growth Factor Receptor by Quantitative Flow CytometryBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 1 2010Wen-Jun Lan Conventional methods for evaluation of EGFR inhibitors are limited. This study describes a duplexed on-microbead binding assay allowing competitive EGFR inhibitors to be quantificationally evaluated in vitro. Polystyrene microbeads barcoded by fluoresceine isothiocyanate fluorescence as high brightness and low brightness microspheres were coated with receptor tyrosine kinase (RTK) ligand-epidermal growth factor (EGF)/stem cell factor (SCF) and ATP/GTP, respectively. High and low brightness microbeads were mixed and incubated with EGFR and its competitive inhibitor in binding assay buffer. Phycoerythrin (PE) fluorescence-labelled antibody was employed to report the level of EGFR binding to EGF/SCF and ATP/GTP. Values were numbered via PE molecules assessed by quantitative flow cytometry. Results from this study demonstrated that incubation with EGFR identified by PE-labelled antibody can make EGF- and ATP-coated microbeads luminous. And EGF or ATP-competitive EGFR inhibitors, respectively, alleviated this in a concentration-dependent manner. Coating microbeads with SCF or GTP as a negative control cannot capture EGFR. The duplexed on-microbead binding assay in this study might be useful for discovering ligand- and ATP-competitive EGFR inhibitors in a rapid and quantificational approach. [source] Does the ligand-biopolymer equilibrium binding constant depend on the number of bound ligands?,BIOPOLYMERS, Issue 11 2010Daria A. Beshnova Abstract Conventional methods, such as Scatchard or McGhee-von Hippel analyses, used to treat ligand-biopolymer interactions, indirectly make the assumption that the microscopic binding constant is independent of the number of ligands, i, already bound to the biopolymer. Recent results on the aggregation of aromatic molecules (Beshnova et al., J Chem Phys 2009, 130, 165105) indicated that the equilibrium constant of self-association depends intrinsically on the number of molecules in an aggregate due to loss of translational and rotational degrees of freedom on formation of the complex. The influence of these factors on the equilibrium binding constant for ligand-biopolymer complexation was analyzed in this work. It was shown that under the conditions of binding of "small" molecules, these factors can effectively be ignored and, hence, do not provide any hidden systematic error in such widely-used approaches, such as the Scatchard or McGhee-von Hippel methods for analyzing ligand-biopolymer complexation. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 932,935, 2010. [source] Novel application of flow cytometry: Determination of muscle fiber types and protein levels in whole murine skeletal muscles and heartCYTOSKELETON, Issue 12 2007Connie Jackaman Abstract Conventional methods for measuring proteins within muscle samples such as immunohistochemistry and western blot analysis can be time consuming, labor intensive and subject to sampling errors. We have developed flow cytometry techniques to detect proteins in whole murine heart and skeletal muscle. Flow cytometry and immunohistochemistry were performed on quadriceps and soleus muscles from male C57BL/6J, BALB/c, CBA and mdx mice. Proteins including actins, myosins, tropomyosin and ,-actinin were detected via single staining flow cytometric analysis. This correlated with immunohistochemistry using the same antibodies. Muscle fiber types could be determined by dual labeled flow cytometry for skeletal muscle actin and different myosins. This showed similar results to immunohistochemistry for I, IIA and IIB myosins. Flow cytometry of heart samples from C57BL/6J and BALB/c mice dual labeled with cardiac and skeletal muscle actin antibodies demonstrated the known increase in skeletal actin protein in BALB/c hearts. The membrane-associated proteins ,-sarcoglycan and dystrophin could be detected in C57BL/6J mice, but were decreased or absent in mdx mice. With the ability to label whole muscle samples simultaneously with multiple antibodies, flow cytometry may have advantages over conventional methods for certain applications, including assessing the efficacy of potential therapies for muscle diseases. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] Cervical cytology reading times: A comparison between thinprep imager and conventional methodsDIAGNOSTIC CYTOPATHOLOGY, Issue 9 2007Elizabeth Davey MBBS Abstract We aimed to compare the times cytologists spend reviewing cervical cytology slides processed by the ThinPrep Imager® (TPI) with times they spend examining conventional cytology (CC) slides. We also aimed to examine the effect of cytologists' experience on reading times. Using a cross-sectional analytical design, we analyzed routine laboratory data, collected retrospectively over 7 months, for 41 cytologists, including paired data for 20 who read both TPI and CC slides. For the 20 cytologists who read both types of cytology, the mean reading rate was 13.3 slides per hour for TPI slides and 6.1 slides per hour for CC slides. The mean within-reader difference between TPI and CC rates was 7.2 slides per hour (P < 0.001). For CC reading, mean times did not differ between those who were additionally trained to read TPI slides and those who only read CC. Slower readers had greater increases in speed when using the TPI compared with CC reading than did faster readers (P < 0.001). More experienced cytologists tended to read CC slides more quickly than did those less experienced, but experience did not affect TPI reading times or within-reader differences in reading times between cytology types. The TPI significantly reduced reading times compared with CC. This reduction was greater amongst slower readers, and was unrelated to experience. Diagn. Cytopathol. 2007;35:550,554. © 2007 Wiley-Liss, Inc. [source] GMM with Weak IdentificationECONOMETRICA, Issue 5 2000James H. Stock This paper develops asymptotic distribution theory for GMM estimators and test statistics when some or all of the parameters are weakly identified. General results are obtained and are specialized to two important cases: linear instrumental variables regression and Euler equations estimation of the CCAPM. Numerical results for the CCAPM demonstrate that weak-identification asymptotics explains the breakdown of conventional GMM procedures documented in previous Monte Carlo studies. Confidence sets immune to weak identification are proposed. We use these results to inform an empirical investigation of various CCAPM specifications; the substantive conclusions reached differ from those obtained using conventional methods. [source] A new approach to long QT syndrome mutation detection by Sequenom MassARRAY® systemELECTROPHORESIS, Issue 10 2010Catarina Allegue Abstract Congenital long QT syndrome is an inherited cardiac disorder characterized by a prolonged QT interval and polymorphic ventricular arrhythmias that could result in recurrent syncope, seizures or sudden death as the most dramatic event. Until now QT interval mutations have been described in 12 genes, where the majority of mutations reside in three genes KCNQ1, KCNH2, and SCN5A. Diagnosis and prognosis are directly related with the gene and mutation involved. We have developed a diagnostic approach for long QT syndrome and Brugada syndrome based on published mutations and Sequenom MassArray® system. Three diagnostic tests have been developed, oriented to each of the three most prevalent genes in the long QT syndrome. A total of 433 mutations are analyzed in 38 multiplex reactions, allowing their detection in about 48,h. Tests were validated on 502 samples from individuals with different clinical conditions and family history. The average call rates obtained for each of the tests were 93, 83, and 73% in KCNQ1, KCNH2, and SCNA, respectively. Sequenom MassARRAY mutation detection is a reliable, highly flexible, and cost-efficient alternative to conventional methods for genetic testing in long QT syndrome and Brugada syndrome, facilitating flexible upgrades of the version of the test presented here with the inclusion of new mutations. [source] An optimal method of DNA silver staining in polyacrylamide gelsELECTROPHORESIS, Issue 6 2008Yan-Chuang Han Abstract DNA silver staining has widely been used to detect DNA fragments in polyacrylamide gels with high sensitivity. We developed an optimal method for DNA silver staining on polyacrylamide gels. The novel procedure can be completed within 10,min instead of over 20,min with the conventional methods. The sensitivity is significantly improved by the silver-ion sensitizer (Eriochrome black T (EBT)) and the minimum of 0.11 and 1.75,ng of DNA amount can be detected in denaturing and nondenaturing polyacrylamide gel, respectively. Compared with the conventional silver staining methods, the improved optimal method can save time and display high sensitivity, color uniformity, and long storage time of the staining gels. [source] Storage stability study of margarines produced from enzymatically interesterified fats compared to margarines produced by conventional methods.EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7-8 2005Physical properties Abstract In this study, margarine hardstocks were produced from two enzymatically interesterified fats at conversion degrees of 80 and 100%, a chemically randomized fat and a physically mixed fat, respectively. These four hardstocks blended with 50% of sunflower oil were mainly used for the production of table margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25,°C during 12,wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by conventional methods and to selected commercial products. The changes in the physical properties of margarines, including hardness, dropping point, crystal form, and sensory evaluation, were examined during storage. It was observed that margarine storage stability increased with increasing conversion degree. The color of margarines made from the enzymatically interesterified fats was more similar to that of the physically mixed fat than that of the margarine from the chemically randomized fat, which had less color. Crystal transformation was accelerated at high storage temperature. Crystal size was not only related to the types of crystals, but also to the driving force of temperature difference. A larger crystal size was observed at 5,°C than at 25,°C for the margarine made from the blend. Margarines produced from interesterified fats had better physical properties than the blend. Overall, the margarine produced from the enzymatically fully converted fat had physical properties similar to the margarine produced from the chemically interesterified fat. [source] Ultrastructural preservation of rat embryonic dental tissues after rapid fixation and dehydration under microwave irradiationEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2000Luciana F. Massa Adequate preservation of the cells and matrix of mineralising tissues remains difficult, as organic components and initial mineral deposits may be lost during conventional processing for electron microscopy. In this study, we have reduced significantly the processing time using microwave irradiation. Rat molar tooth germs were fixed in 4% glutaraldehyde+4% formaldehyde with 0.1 M sodium cacodylate in a laboratory microwave oven for two periods of 20 s with a maximal temperature of 37°C. After conventional washing and post-fixation, specimens were dehydrated in graded ethanols under microwave irradiation for a total of 7 min 20 s. For comparison, some specimens were processed by conventional methods. After embedding, ultrathin sections were examined by electron microscopy. In differentiating ameloblasts and odontoblasts, plasma membranes, mitochondria, rough endoplasmic reticulum, the Golgi complex, together with all other cytoplasmic organelles exhibited excellent preservation. Microtubules, microfilaments and coated vesicles were particularly evident. Crystal-like mineral deposits were conspicuously present in relation to dentine matrix vesicles and collagen fibrils as well as in enamel matrix. The matrix of forming enamel had a globular electron-lucent appearance. It is concluded that this is a rapid method which provides a preserved or even improved morphology. [source] Neutron Reflectometry: A Tool to Investigate Diffusion Processes in Solids on the Nanometer Scale,ADVANCED ENGINEERING MATERIALS, Issue 6 2009Harald Schmidt Abstract The investigation of self-diffusion for the characterization of kinetic process in solids is one of the most fundamental tasks in materials science. We present the method of neutron reflectometry (NR), which allows the detection of extremely short diffusion lengths in the order of 1,nm and below at corresponding low self-diffusivities between 10,25 and 10,20,m2 s,1. Such a combination of values cannot be achieved by conventional methods of diffusivity determination, like the radiotracer method, secondary ion mass spectrometry, quasielastic neutron scattering, or nuclear magnetic resonance. Using our method, the extensive characterization of materials which are in a non-equilibrium state, like amorphous or nanocrystalline solids becomes possible. Due to the small experimentally accessible diffusion length microstructural changes (grain growth and crystallization) taking place simultaneously during the actual diffusion experiment can be avoided. For diffusion experiments with NR isotope multilayers are necessary, which are chemical homogeneous but isotope modulated films. We illustrate the basic aspects and potential of this technique using model systems of different classes of materials: single crystalline germanium, amorphous silicon nitride, and nanocrystalline iron. [source] Improved genetic algorithm for multi-objective reactive power dispatch problemEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2007D. DevarajArticle first published online: 12 JAN 200 Abstract This paper presents an improved genetic algorithm (GA) approach for solving the multi-objective reactive power dispatch problem. Loss minimization and maximization of voltage stability margin are taken as the objectives. Maximum L-index of the system is used to specify the voltage stability level. Generator terminal voltages, reactive power generation of capacitor banks and tap changing transformer setting are taken as the optimization variables. In the proposed GA, voltage magnitudes are represented as floating point numbers and transformer tap-setting and reactive power generation of capacitor bank are represented as integers. This alleviates the problems associated with conventional binary-coded GAs to deal with real variables and integer variables with total number of permissible choices not equal to 25. Crossover and mutation operators which can deal with mixed variables are proposed. The proposed method has been tested on IEEE 30-bus system and is compared with conventional methods and binary-coded GA. The proposed method has produced the loss which is less than the value reported earlier and is well suitable for solving the mixed integer optimization problem. Copyright © 2007 John Wiley & Sons, Ltd. [source] CAC and routing for multi-service networks with blocked wide-band calls delayed, Part II: approximative link MDP frameworkEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2007Ernst Nordström In this paper, we study the call admission control (CAC) and routing issue in multi-service networks. Two categories of calls are considered: a narrow-band with blocked calls cleared and a wide-band with blocked calls delayed. The optimisation is subject to several quality of service (QoS) constraints, either on the packet or call level. The objective function is formulated as reward maximisation with penalty for delay. A suboptimal solution is achieved by applying Markov decision process (MDP) theory together with a three-level approximation. First, the network is decomposed into a set of links assumed to have independent Markov and reward processes respectively. Second, the dimensions of the link Markov and reward processes are reduced by aggregation of the call classes into call categories. Third, by applying decomposition of the link Markov process, the link MDP tasks are simplified considerably. The CAC and routing policy is computed by the policy iteration algorithm from MDP theory. The numerical results show that the proposed CAC and routing method, based on the approximate link MDP framework, is able to find an efficient trade-off between reward loss and average call set-up delay, outperforming conventional methods such as least loaded routing (LLR). Copyright © 2006 AEIT. [source] CAC and routing for multi-service networks with blocked wide-band calls delayed, part I: exact link MDP frameworkEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2006Ernst Nordström In this paper, we study the call admission control (CAC) and routing issue in multi-service networks. Two categories of calls are considered: a narrow-band (NB) with blocked calls cleared and a wide-band (WB) with blocked calls delayed. The objective function is formulated as reward maximisation with penalty for delay. The optimisation is subject to quality of service (QoS) constraints and, possibly, grade of service (GoS) constraints. A suboptimal solution is achieved by applying Markov decision process (MDP) theory together with a two-level approximation. First, the network is decomposed into a set of links assumed to have independent Markov and reward processes respectively. Second, the dimensions of the link Markov and reward processes are reduced by aggregation of the call classes into call categories. The CAC and routing policy is computed by the policy iteration algorithm from MDP theory. The numerical results show that the proposed CAC and routing method, based on the exact link MDP framework, is able to find an efficient trade-off between reward loss and average call set-up delay, outperforming conventional methods such as the least loaded routing (LLR). Copyright © 2005 AEIT. [source] Hydroacoustic target strength validation using angling creel census dataFISHERIES MANAGEMENT & ECOLOGY, Issue 6 2002P. A. FREAR Validation of hydroacoustic in-situ target strength is problematic in large, deep lowland rivers, which cannot be sampled easily by conventional methods such as netting or electric fishing. A sampling programme involving three different techniques (split beam sonar, angling census and post-angling competition data collection) was conducted to examine methodologies suitable for target strength validation. This combination of techniques also assessed the relative merits of each method for best describing fish populations and the stocks exploited in a recreational coarse fishery. The sonar estimated the greatest number of fish of the three techniques, with a strong positive size correlation with the other two methods. The angling census and post-competition census accounted for more larger fish, >26 cm, than were detected acoustically, indicating a stratification of species that were exploited by angling but not detected by horizontal sonar. The combined techniques demonstrated a suitable, cost-effective, hydroacoustic validation method for large UK rivers, which supports recreational coarse fisheries management, with the added advantage of species identification. [source] Selectivity and competitive interactions between two benthic invertebrate grazers (Asellus aquaticus and Potamopyrgus antipodarum): an experimental study using 13C- and 15N-labelled diatomsFRESHWATER BIOLOGY, Issue 2 2005N. ABERLE Summary 1. Tracer experiments with two diatoms labelled with 13C (Nitzschia palea) and 15N (Fragilaria crotonensis), were conducted to investigate feeding selectivity and interspecific competition between the grazers Asellus aquaticus (Isopoda, Crustacea) and Potamopyrgus antipodarum (Hydrobiidae, Gastropoda). Conventional methods, such as cell counts and estimated biovolume, were used first to detect feeding preferences within the different grazer treatments. 2. The results revealed a significant decline in algal biovolume in all grazer treatments and no indications of active selectivity were observed. In contrast to conventional methods, measurements based on isotope signatures showed strong differences in tracer uptake, thus indicating different degrees of assimilation and digestion by the two grazers. 3. The selectivity index Q, which provides information on the uptake ratio of 13C to 15N, showed a significant time effect for both grazer species and a significant difference between single- and mixed-grazer treatments for P. antipodarum. Thus, this technique enabled the direct quantification of the uptake by grazers and, therefore, served as an ideal tool for the detection of passive selectivity. 4. Our results indicate a shift in feeding preferences related to between-species competition and a potential divergence of trophic niches when species coexist. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||