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Selected AbstractsThe three-dimension finite element analysis of stress in posterior tooth residual root restored with postcore crownDENTAL TRAUMATOLOGY, Issue 1 2010Gang Fu Some researchers have analyzed the stress of the anterior teeth after postcore crown restoration, but the stress of the posterior teeth after such restoration has not been reported. We used three-dimension finite element methods to analyze the stress magnitude and distribution of remaining dentin in posterior tooth residual root restored with postcore crown. The binding material, loading direction, number, length and material of posts were studied. Methods:, The models of residual root of maxillary first molar restored with postcore crown were created by CT scanning, mimics software and abaqus software. Different number, length and material of posts were used in the modeling. The posts were cemented with zinc-phosphate cement or composited resin. A load of 240 N was applied to the occlusal surface in four directions and tensile, shear, and von Mises stresses were calculated. Result:, (i) The maximum stress on remaining dentin changed irregularly as the number and length of posts changed. (ii) The maximum stress on remaining dentin decreased slightly as elastic modulus of the material of posts increased. (iii) The maximum stress on bonding layer and remaining dentin was lower when bonded with resin luting agent than with zinc-phosphate cement. (iv) The maximum stress on remaining dentin increased markedly as loading angle increased. Conclusion:, The number, length, material of posts, bonding material and loading angle all have influence on the magnitude and distribution of stress. The influence of loading angle is most apparent. [source] Variations of 18S rDNA Loci Among Six Populations of Paeonia obovata Maxim. (Paeoniaceae) Revealed by Fluorescence In Situ HybridizationJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2006Rui Luo Abstract The localization of 18S ribosomal RNA genes (rDNA) by fluorescence in situ hybridization (FISH) had been performed for some species of Paeonia. However, the pattern of 18S rDNA loci among populations is indistinct. In the present study, we localized 18S rDNA loci on meiotic or mitotic chromosomes of six populations of Paeonia obovata Maxim. (Paeoniaceae). Different numbers of rDNA loci were found with different diploid (2n=10) populations, namely eight (Lushi and Mt. Jiuhua populations), 10 (Mt. Taibai population), and seven (Mt. Guandi population), whereas tetraploid (2n=20) populations were all found with 16 loci. All rDNA loci were mapped near telomeres of mitotic chromosomes and there was no chromosome with two loci. The present results show that molecular cytological polymorphism exists among P. obovata diploid populations, indicating that structural variations occurred frequently during the evolutionary history of this species, accompanied with differentiation among populations. (Managing editor: Wei Wang) [source] Combinational polymorphisms of four DNA repair genes XRCC1, XRCC2, XRCC3, and XRCC4 and their association with oral cancer in TaiwanJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 5 2008Ching-Yu Yen Background:, Many single nucleotide polymorphisms (SNPs) have been found to be associated with oral cancer but the biological interactions through SNPs are seldom addressed. In this study, we focused on the joint effect for SNP combinations of four DNA repair genes, X-ray repair cross-complementing groups (XRCCs) 1,4, involved in major cancer-related pathways. Methods:, Single nucleotide polymorphism genotyping was determined using by polymerase chain reaction-restriction fragment length polymorphism in this study (case = 103, control = 98). Different numbers of combinational SNPs with genotypes called the pseudo-haplotypes from these chromosome-wide genes were used to evaluate their joint effect on oral cancer risk. Results:, Except for XRCC2 rs2040639-AG, none of these SNPs was found to individually contribute to oral cancer risk. However, for two combined SNPs, the proportion of subjects with oral cancer was significantly higher in the pseudo-haplotype with AG-CC genotypes in rs2040639-rs861539 (XRCC2,XRCC3) compared with those with non-AG-CC genotypes. Similarly, the pseudo-haplotype of rs2040639,rs861539,rs2075685 (XRCC2,XRCC3,XRCC4) and rs2040639,rs861539,rs2075685,rs1799782 (XRCCs 1,4) with specific genotype pattern (AG-CC-TG and CT-AG-CC-TG) among three and four combinational SNPs were significantly associated with oral cancer. After controlling for age, gender, smoking, drinking, and betel nut chewing, the estimated odds ratio of oral cancer were 2.45, 5.03, and 10.10 for two, three and four specific SNP combinations, respectively, comparing these specific pseudo-haplotypes to their corresponding non-pseudo-haplotypes. Conclusion:, We have identified the potential combined XRCCs 1,4 SNPs with genotypes that were associated with oral cancer risk and may have an impact on identification of a high-risk population. [source] Phenotypic plasticity, polymorphism and phylogeny within placodermsACTA ZOOLOGICA, Issue 2009K. Trinajstic Abstract Intraspecies variation, polymorphism and asymmetric traits are observed within two families of Arthrodira, the Incisoscutidae and Camuropiscidae, from the Gogo Formation in northern Western Australia. Individual plates of the head and trunk shield show considerable variation between individuals. Plates that show the greatest degree polymorphic traits are the rostral (R), marginal (M), submarginal (SM), preorbital (PrO), anterior dorsolateral, anterior median ventral (AMV) and posterior ventrolateral (PVL) plates. The paths of the sensory line canals are the most variable feature and the dermal plates of the cheek show the greatest asymmetry. It is apparent that if anatomical data in arthrodires are to be interpreted with greater precision, detailed knowledge of intraspecies variation, polymorphic and asymmetric traits is essential. How these variables are treated in cladistic analysis is also critical. Here multistate characters were coded differently in five discrete analyses, each analysis yielding a different number of trees and relationships. It was concluded that including and coding for multistate characters gave the most robust tree. In addition, further morphological characters from a new specimen of Gogosteus sarahae Long (1994) indicates many of the characters used to separate this genus from Incisoscutum are inconsistent and so it is here considered that the genus Gogosteus is a junior synonym of Incisoscutum. [source] Flammability ranking of foliage species by factor analysis of physical and chemical pyric propertiesFIRE AND MATERIALS, Issue 6 2008Yanlong Shan Abstract In this paper, factor analysis is introduced to evaluate the flammability of 55 foliage species that may be used in China for construction of the fuel break network of forest strips with lower flammability. Six pyric parameters, i.e. air dry moisture content, absolute dry moisture content, ignition point, ash content, caloric value and extractive content, are measured and used as variables for factor analysis. The covariance analysis shows that four principal factors can be extracted to reflect the flammability in different physical and chemical senses. In terms of the contributions of the four factors to the variances and the physical significance of the relevant parameters, the four factors are, respectively, termed as ,flaming factor,' ,air dry factor,' ,ash factor' and ,absolute dry factor.' The stability of the factor analysis method is examined by a different number of samples considered, and the variation degrees of the orderings indicate that the method has high reliability to measure the total flammability of foliage species. The results of the flammability evaluation are verified by comparison with the recommended tree species in the Chinese technology standard. Copyright © 2008 John Wiley & Sons, Ltd. [source] Predicting river water temperatures using stochastic models: case study of the Moisie River (Québec, Canada)HYDROLOGICAL PROCESSES, Issue 1 2007Behrouz Ahmadi-Nedushan Abstract Successful applications of stochastic models for simulating and predicting daily stream temperature have been reported in the literature. These stochastic models have been generally tested on small rivers and have used only air temperature as an exogenous variable. This study investigates the stochastic modelling of daily mean stream water temperatures on the Moisie River, a relatively large unregulated river located in Québec, Canada. The objective of the study is to compare different stochastic approaches previously used on small streams to relate mean daily water temperatures to air temperatures and streamflow indices. Various stochastic approaches are used to model the water temperature residuals, representing short-term variations, which were obtained by subtracting the seasonal components from water temperature time-series. The first three models, a multiple regression, a second-order autoregressive model, and a Box and Jenkins model, used only lagged air temperature residuals as exogenous variables. The root-mean-square error (RMSE) for these models varied between 0·53 and 1·70 °C and the second-order autoregressive model provided the best results. A statistical methodology using best subsets regression is proposed to model the combined effect of discharge and air temperature on stream temperatures. Various streamflow indices were considered as additional independent variables, and models with different number of variables were tested. The results indicated that the best model included relative change in flow as the most important streamflow index. The RMSE for this model was of the order of 0·51 °C, which shows a small improvement over the first three models that did not include streamflow indices. The ridge regression was applied to this model to alleviate the potential statistical inadequacies associated with multicollinearity. The amplitude and sign of the ridge regression coefficients seem to be more in agreement with prior expectations (e.g. positive correlation between water temperature residuals of different lags) and make more physical sense. Copyright © 2006 John Wiley & Sons, Ltd. [source] Correlations of flow maldistribution parameters in an air cooled heat exchangerINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2008M. A. Habib Abstract The present paper provides correlations of flow maldistribution parameters in air-cooled heat exchangers. The flow field in the inlet header was obtained through the numerical solution of the governing partial differential equations including the conservation equations of mass and momentum in addition to the equations of the turbulence model. The results were obtained for different number of nozzles of 2,4, different inlet flow velocities of 1,2.5m/s and different nozzle geometries in addition to incorporation of a second header. The results are presented in terms of mass flow rate distributions in the tubes of the heat exchanger and their standard deviations. The results indicate that the inlet flow velocity has insignificant influence on maldistribution while the nozzle geometry shape has a slight effect. Also, the results indicate that reducing the nozzle diameter results in an increase in the flow maldistribution. A 25% increase is obtained in the standard deviation as a result of decreasing the diameter by 25%. Increasing the number of nozzles has a significant influence on the maldistribution. A reduction of 62.5% in the standard deviation of the mass flow rate inside the tubes is achieved by increasing the number of nozzles from 2 to 4. The results indicate that incorporating a second header results in a significant reduction in the flow maldistribution. A 50% decrease in the standard deviation is achieved as a result of incorporation of a second header of seven holes. It is also found that the hole-diameter distribution at the exit of the second header has a slight influence on the flow maldistribution. Correlations of the flow maldistribution in terms of the investigated parameters are presented. Copyright © 2007 John Wiley & Sons, Ltd. [source] Erlang capacity analysis of hybrid FDMA/CDMA systems supporting multi-class services according to channel assignment methodsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2002Insoo Koo Abstract In this paper, we focus on the evaluation of the Erlang capacity for hybrid FDMA/CDMA systems supporting multi-class services with two channel allocation schemes: independent carrier channel assignment (ICCA) and combined carrier channel assignment (CCCA). For the performance analysis, a multi-dimensional Markov chain model is developed. The effect of the number of carriers of hybrid FDMA/CDMA system on the Erlang capacity is observed, and the optimum values of the system parameters such as the number of channel elements (CEs) and the number of carriers are selected with respect to the Erlang capacity. As a numerical example, we consider an FDMA/CDMA system supporting voice/data services. We find out that, even though the benefit of CCCA scheme over ICCA scheme is negligible for small number of CEs, the scenario changes significantly when the number of CEs increases beyond a certain point. An improvement of as much as 74% can be achieved in the Erlang capacity when 5 carriers are employed. We also find the capacity knees for different number of carriers. The results of this paper could be helpful in the traffic engineering of FDMA/CDMA systems providing multi-class services. Copyright © 2002 John Wiley & Sons, Ltd. [source] A comparison of congestion control and time slot algorithms in Internet transmission performanceINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2002Chyan Yang Abstract The characteristics of TCP and UDP lead to different network transmission behaviours. TCP is responsive to network congestion whereas UDP is not. This paper proposes two mechanisms that operate at the source node to regulate TCP and UDP flows and provide a differential service for them. One is the congestion-control mechanism, which uses congestion signal detected by TCP flows to regulate the flows at the source node. Another is the time-slot mechanism, which assigns different number of time slots to flows to control their flow transmission. Based on the priority of each flow, different bandwidth proportions are allocated for each flow and differential services are provided. Simulation results show some insights of these two mechanisms. Moreover, we summarize the factors that may impact the performance of these two mechanisms. Copyright © 2001 John Wiley & Sons, Ltd. [source] A digital predistorter for wireless transmittersINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2009D. Bondar Abstract A novel digital baseband predistorter with improved reduction of spectral regrowth is proposed and investigated. The improvements are achieved by using a proposed predistortion technique and extended power amplifier (PA) fundamental-frequency modeling. The digital baseband predistortion (DPD), known for its simplicity of realization, low cost and integrability; however, it suffers from poor linearizing performances. We incorporate baseband iterative injection of in-band distortion components into the baseband DPD to enhance the nonlinearity compensation. General formulas for the fundamental-frequency output of a PA with n -order nonlinearity and recursive formulas for calculating the injected components for different number of iterations are developed. The proposed iterative digital baseband predistorter is verified experimentally with a wireless PA and measured results are presented to demonstrate feasibility of the proposed concept. The spectral regrowth suppression of 20 dB is achieved for a 3.5 MHz digitally modulated signal. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. [source] Bayesian inference in a piecewise Weibull proportional hazards model with unknown change pointsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 4 2007J. Casellas Summary The main difference between parametric and non-parametric survival analyses relies on model flexibility. Parametric models have been suggested as preferable because of their lower programming needs although they generally suffer from a reduced flexibility to fit field data. In this sense, parametric survival functions can be redefined as piecewise survival functions whose slopes change at given points. It substantially increases the flexibility of the parametric survival model. Unfortunately, we lack accurate methods to establish a required number of change points and their position within the time space. In this study, a Weibull survival model with a piecewise baseline hazard function was developed, with change points included as unknown parameters in the model. Concretely, a Weibull log-normal animal frailty model was assumed, and it was solved with a Bayesian approach. The required fully conditional posterior distributions were derived. During the sampling process, all the parameters in the model were updated using a Metropolis,Hastings step, with the exception of the genetic variance that was updated with a standard Gibbs sampler. This methodology was tested with simulated data sets, each one analysed through several models with different number of change points. The models were compared with the Deviance Information Criterion, with appealing results. Simulation results showed that the estimated marginal posterior distributions covered well and placed high density to the true parameter values used in the simulation data. Moreover, results showed that the piecewise baseline hazard function could appropriately fit survival data, as well as other smooth distributions, with a reduced number of change points. [source] Fixed or random contemporary groups in genetic evaluation for litter size in pigs using a single trait repeatability animal modelJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2003D. Babot Summary The importance of using fixed or random contemporary groups in the genetic evaluation of litter size in pigs was analysed by using farm and simulated data. Farm data were from four Spanish pig breeding populations, two Landrace (13 084 and 13 619 records) and two Large White (2762 and 8455 records). A simulated population (200 sows and 10 boars) selected for litter size, in which litter size was simulated using a repeatability animal model with random herd,year,season (HYS), was used to obtain simulated data. With farm data, the goodness-of-fit and the predictive ability of a repeatability animal model were calculated under several definitions of the HYS effect. A residual maximum likelihood estimator of the HYS variance in each population was obtained as well. In this sense, HYS was considered as either fixed or random with different number of individuals per level. Results from farm data showed that HYS variance was small in relation to the total variance (ranging from 0.01 to 0.04). The treatment of HYS effect as fixed, reduced the residual variance but the size of HYS levels does not explain by itself the goodness-of-fit of the model. The results obtained by simulation showed that the predictive ability of the model is better for random than for fixed HYS models. However, the improvement of predictive ability does not lead to a significant increase of the genetic response. Finally, results showed that random HYS models biased the estimates of genetic response when there is an environmental trend. Zusammenfassung Fixe oder zufällige Vergleichsgruppen bei der Zuchtwertschätzung für Wurfgröße beim Schwein mit einem Wiederholbarkeits-Tiermodell Der Einfluss von fixen oder zufälligen Vergleichgruppen bei der Zuchtwertschätzung für Wurfgröße beim Schwein wurde an realen Betriebsdaten und an simulierten Daten untersucht. Die Betriebsdaten stammen von vier spanischen Zuchtpopulationen, zwei Landrasse Populationen (13084 und 13619 Datensätze) und zwei Large White Populationen (2762 und 8455 Datensätze). Für die Simulation wurde eine Population (200 Sauen und 10 Eber), die auf Wurfgröße selektiert wurde, unter Berücksichtigung eines Wiederholbarkeitsmodelles und mit zufälligen Herden-Jahr-Saisonklassen simuliert. Anhand der Betriebsdaten wurde die Güte des Modells und die Vorhersagegenauigkeit des Wiederholbarkeitsmodelles mit verschiedenen Definitionen der Herden-Jahr-Saisonklassen geprüft. Mittels der REML-Methode wurden auch Varianzkomponenten für die Herden-Jahr-Saisonklassen geschätzt. Die Herden-Jahr-Saisonklassen wurden als fixer bzw. zufälliger Effekt mit unterschiedlicher Anzahl an Tieren pro Klasse im Modell berücksichtigt. Die Ergebnisse der Betriebsdaten ergaben, dass die Varianz für die Herden-Jahr-Saisonklassen nur einen kleinen Teil der Totalvarianz (von 0,01 bis 0,04) ausmachte. Mit den Herden-Jahr-Saisonklassen als fixer Effekt reduzierte sich die Restvarianz, aber die Größe der Herden-Jahr-Saisonklassen bestimmte nicht allein die Güte des Modells. Die Erhöhung der Vorhersagegenauigkeit ergab keinen signifikanten Anstieg des genetischen Fortschrittes. Abschließend bleibt festzustellen, dass Modelle mit zufälligen Herde-Jahr-Saisonklassen zu einem Bias des geschätzten genetischen Erfolges führten, wenn ein Umwelttrend vorhanden war. [source] Differential expression of human Polycomb group proteins in various tissues and cell typesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S36 2001Marco J. Gunster Abstract Polycomb group proteins are involved in the maintenance of cellular identity. As multimeric complexes they repress cell type-specific sets of target genes. One model predicts that the composition of Polycomb group complexes determines the specificity for their target genes. To study this hypothesis, we analyzed the expression of Polycomb group genes in various human tissues using Northern blotting and immunohistochemistry. We found that Polycomb group expression varies greatly among tissues and even among specific cell types within a particular tissue. Variations in mRNA expression ranged from expression of all analyzed Polycomb group genes in the heart and testis to no detectable Polycomb group expression at all in bone marrow. Furthermore, each Polycomb group gene was expressed in a different number of tissues. RING1 was expressed in practically all tissues, while HPH1 was expressed in only a few tissues. Also within one tissue the level of Polycomb group expression varied greatly. Cell type-specific Polycomb group expression patterns were observed in thyroid, pancreas, and kidney. Finally, in various developmental stages of fetal kidney, different Polycomb group expression patterns were observed. We conclude that Polycomb group expression can vary depending on the tissue, cell type, and development stage. Polycomb group complexes can only be composed of the Polycomb group proteins that are expressed. This implies that with cell type-specific Polycomb group expression patterns, cell type-specific Polycomb group complexes exist. The fact that there are cell type-specific Polycomb group targets and cell type-specific Polycomb group complexes fits well with the hypothesis that the composition of Polycomb group complexes may determine their target specificity. J. Cell. Biochem. Suppl. 36: 129,143, 2001. © 2001 Wiley-Liss, Inc. [source] Health Economics Perspective of the Components of the Cardiometabolic SyndromeJOURNAL OF CLINICAL HYPERTENSION, Issue 7 2010Leonardo Tamariz MD J ClinHypertens (Greenwich). 2010;12:549,555. © 2010 Wiley Periodicals, Inc. The components of the cardiometabolic syndrome (CMS) increase the risk of coronary artery disease (CAD). The authors compared 12-month costs of subjects with different number of components of the CMS. In claims data from a large health benefits company, 383,420 individuals with the first International Classification of Diseases, Ninth Revision codes for hypertension, diabetes, lipid abnormalities, and obesity were identified. Patients were stratified according to presence of CAD and the number of components of the CMS. Twelve-month costs were added after the identification of the risk factor. Mean annual costs increased with the number of components of CMS both in those with and without CAD, even after adjusting for age, sex, and comorbidities (P<.01). Similar trends were seen for medical and pharmacy costs. The adjusted total annual health care cost in those with an isolated component of the CMS was $5564 (95% confidence interval: $5491,$5631) while in those with 4 components was $12,287 (95% confidence interval: $11,987,$12,587). Individuals with accumulating components of the CMS have higher health care costs regardless of age, sex, and other comorbidities. [source] Influence of phenylenediamine additions on the morphology and on the catalytic effect of polyanilineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2004Ljerka Dui Abstract The influence of para -, ortho -, and meta -phenylenediamine (p -, o -, and m -PDA) additions on the electrochemical synthesis of polyaniline has been investigated by the use of cyclic voltametry. It has been found that small additions (1 and 5 mmol L,1) of PDA monomers influence significantly the polymerization rate. Whereas p -PDA increases the polymerization rate, the addition of o - or m -PDA slows it down. Therefore, a different number of potential cycling is necessary to obtain similar thickness of layers. The layers exhibit very different morphology, which changes from "spaghetti-like" for polyaniline to "sponge-like" for p -PDA, to "pebble-like" for o -PDA and to "cauliflower-like" for m -PDA additions, respectively. The catalytic effect of the synthesized polymer layers has been tested. It has been found that all the layers exhibit catalytic effect in lowering the redox potential of hydroquinone/quinone tested reaction, but the rate of the electrocatalytic reaction varies depending on the PDA monomer added. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1599,1608, 2004 [source] Synthesis, characterization, and in vitro degradation of thermotropic polyesters and copolyesters based on terephthalic acid, 3-(4-hydroxyphenyl)propionic acid, and glycolsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2001Minoru Nagata Abstract A new series of thermotropic liquid-crystalline (LC) polyesters were prepared from a diacyl chloride derivative of 4,4,-(terephthaloyldioxy)-di-4-phenylpropionic acid (PTP) and glycols with a different number of methylene groups (n) [HO(CH2)n OH, n = 6,10, 12] by high-temperature solution polycondensation in diphenyl oxide. PTP6/10 and PTP6/hydroquinone (H) LC copolyesters were also prepared according to a similar procedure. The chemical structure, LC, phase-transition behaviors, thermal stability, and solubility were characterized by elemental analysis, Fourier transform infrared spectroscopy, 1H and 13C NMR spectra, differential scanning calorimetry (DSC), thermogravimetric analysis, and a polarizing light microscope. The melting and isotropization temperatures decreased in a zigzag manner as the number of n increased. All of the polyesters formed a nematic phase with the exception of PTP8. The temperature ranges of the mesophase (,T) were much wider for the polyesters with an odd number of n's than those with an even number. ,T increased markedly for the PTP6/10 and PTP6/H copolyesters. The in vitro degradations of the polymers were ascertained by enzymatic hydrolysis and alkaline hydrolysis. The model compound, PTP dihexylester, was synthesized and found to be degraded into terephthalic acid, 3-(4-hydroxyphenyl)propionic acid, and 1-hexanol by Rhizopus delemar lipase, but PTPn homopolyesters and PTP6/10 and PTP6/H copolyesters were resistant to Rhizopus delemar hydrolysis. They were degradable in a sodium hydroxide buffer solution of pH 12 at 60 °C, depending on the number of n's and the copolymer composition. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3043,3051, 2001 [source] Orthogonality of silver-ion and non-aqueous reversed-phase HPLC/MS in the analysis of complex natural mixtures of triacylglycerolsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Michal Hol Abstract The goal of this work is the study of possibilities of two basic separation modes used in the analysis of complex triacylglycerol (TG) samples of plant oils and animal fats, i.e. non-aqueous reversed-phase (NARP) and silver-ion HPLC coupled with atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The orthogonality of both separation modes is tested for complex TG mixtures containing fatty acids (FAs) with different acyl chain lengths, different number, positions and geometry of double bonds (DBs) and different regioisomeric positions of FAs on the glycerol skeleton. The retention in NARP mode is governed by the equivalent carbon number, while the retention in silver-ion chromatography increases with the increasing number of DBs with a clear differentiation between cis - and trans- FAs. Moreover, silver-ion mode enables at least the partial resolution of regioisomeric TG mixtures including cis -/trans -regioisomers, as illustrated on two examples of randomization mixtures. Off-line 2D coupling of both complementary modes (NARP in the first dimension and silver-ion in the second dimension) yields the superior chromatographic selectivity resulting in the highest number of identified TGs ever reported for studied samples. Off-line 2D chromatograms are processed with the home-made software providing various ways of data visualization. [source] Optimization of sigma amplitude threshold in sleep spindle detectionJOURNAL OF SLEEP RESEARCH, Issue 4 2000E. Huupponen Sleep spindles are transient EEG waveforms of non-rapid eye movement sleep. There is considerable intersubject variability in spindle amplitudes. The problem in automatic spindle detection has been that, despite this fact, a fixed amplitude threshold has been used. Selection of the spindle detection threshold value is critical with respect to the sensitivity of spindle detection. In this study a method was developed to estimate the optimal recording-specific threshold value for each all-night recording without any visual scorings. The performance of the proposed method was validated using four test recordings each having a very different number of visually scored spindles. The optimal threshold values for the test recordings could be estimated well. The presented method seems very promising in providing information about sleep spindle amplitudes of individual all-night recordings. [source] Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 57JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003D Cocito BACKGROUND: Since 1991, five sets of electrophysiological criteria for CIDP have been reported. However, until now, receiver operator characteristic (ROC), such as sensitivity and specificity, of only AAN criteria were investigated, showing a high specificity, but intermediate sensitivity. The application of these criteria may be useful in clinical trials, but is inadequate in clinical practice, since they preclude immunomodulating treatment in patients who do not meet them. OBJECTIVE: 1) to evaluate the ROC and predictive value of five different electrophysiological criteria for CIDP (AAN, INCAT, Rotta et al, Nicholas et al. and Saperstein et al.); 2) to identify the most informative electrophysiological features indicative of demyelination by mean of the likelihood ratio; 3) to determine, in our series of cases, a set of minimal electrophysiological criteria (albeit aspecific) enough sensitive for CIDP diagnosis. PATIENTS AND METHODS: 20 patients with sensorimotor polyneuropathy, progressive for at least 2 months, with weakness in least two limbs and documented improvement in strength in response to immunotherapy. Other potential causes were excluded, including diabetes and IgM paraproteinemia with or without anti-MAG reactivity. Twelve patients with axonal polyneuropathy associated with diabetes and 12 patients with amyotrophic lateral sclerosis were included as controls. Nerve conduction studies (NCS) were evaluated according to all five sets of NCS criteria and ROC was calculated. Likelihood ratio for CIDP was evaluated for each set of NCS criteria and for presence of each of the following features in different number of nerves: motor conduction velocities (MCV), conduction blocks/temporal dispersion, distal motor (DML) and F-wave latencies (FWL). MCV, DML and FWL were considered indicative of demyelination if decreased or increased as suggested by AAN criteria. Results will be discussed. [source] Impact of polyurea structure on grease propertiesLUBRICATION SCIENCE, Issue 9 2010L. Liu Abstract The thickener structure of polyurea grease has a crucial effect on its properties. Therefore, it is very important to study the relationship between a thickener structure and physical and performance properties. In this study, polyurea greases were synthesised, having a different number of urea groups in per polyurea thickener molecule. Properties such as dropping point, penetration, oil separation, shear stability and four-ball wear and extreme pressure (EP) were evaluated. The result shows that properties of polyurea grease vary with the number of urea group per polyurea molecule. Based on molecular theory, the mechanisms explaining these effects are briefly discussed. Copyright © 2010 John Wiley & Sons, Ltd. [source] Study on discontinuous microstrip periodic slow-wave structureMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2009Jun He Abstract In this article, several discontinuous microstrip periodic slow-wave structures, which possess equal electrical length but different number of unit cells, have been designed and measured. The performance of the periodic structure improves when the number of unit cells increases. However, when the number of unit cells increases to some degree, its characteristics, including cutoff frequency, dispersion, and group delay, get better slightly because of the influence of parasitic parameters. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1455,1458, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24402 [source] Left-handed microstrip lines with multiple complementary split-ring and spiral resonatorsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2007-Bengin, V. Crnojevi Abstract Negative-permeability sub-wavelength particles, namely split-ring resonators and spiral resonators, are compared and their performances analyzed for a different number of concentric rings and spiral turns, respectively. Left-handed lines are designed, fabricated, and measured that use multiple complementary split-ring and spiral resonators. More compact structures are obtained, with improved characteristics. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1391,1395, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22427 [source] Presence of two glycolytic gene clusters in a severe pathogenic line of Candidatus Phytoplasma asterisMOLECULAR PLANT PATHOLOGY, Issue 4 2007KENRO OSHIMA SUMMARY Phytoplasmas are plant-pathogenic bacteria that are associated with numerous plant diseases. We have previously reported the complete genomic sequence of Candidatus Phytoplasma asteris, OY strain, OY-M line, which causes mild symptoms. The phytoplasma genome lacks several important metabolic genes, implying that the consumption of metabolites by phytoplasmas in plants may cause disease symptoms. Here we show that the approximately 30-kb region including the glycolytic genes was tandemly duplicated in the genome of OY-W phytoplasma, which causes severe symptoms. Almost duplicated genes became pseudogenes by frameshift and stop-codon mutations, probably because of their functional redundancy. However, five kinds of genes, including two glycolytic genes, remained full-length ORFs, suggesting that it is advantageous for the phytoplasma to retain these genes in its lifestyle. In particular, 6-phosphofructokinase is known as a rate-limiting enzyme of glycolysis, implying that the different number of glycolytic genes between OY-W and OY-M may influence their respective glycolysis activities. We previously reported that the phytoplasma population of OY-W was higher than that of OY-M in their infected plants. Taking this result into account, the higher consumption of the carbon source may affect the growth rate of phytoplasmas and also may directly or indirectly cause more severe symptoms. [source] Frequency of recombinant and nonrecombinant products of pericentric inversion of chromosome 1 in sperm nuclei of carrier: By FISH techniqueMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2003Tahsin Yakut Abstract Meiotic segregation products of carriers with pericentric inversion are very important for assessing the risk of unbalanced forms and appropriate genetic counseling. We investigated the incidence of recombinant and nonrecombinant products of chromosome 1 with pericentric inversion, in the sperm nuclei of the carrier by using triple color fluorescence in situ hybridization (FISH). The centromere specific and telomere specific probes for chromosome 1 were used. In the segregation analysis, 1,636 sperm nuclei were analyzed; 82.5% of the sperms were including normal or inverted chromosome 1, and the dup(p)/del(q) and del(p)/dup(q) recombinant products in sperm nuclei of our carrier were 8.7 and 7.3%, respectively. The number of recombinant products may be dependent on the formation of an inversion loop, which the number of the formation of chiasmata results in the different number of normal/balanced and recombinant products. The use of FISH, using different probe combination, in sperm nuclei has proved to be an accurate approach to determine the meiotic segregation patterns and could help to better establish a reproductive prognosis and genetic counseling. Mol. Reprod. Dev. 66: 67,71, 2003. © 2003 Wiley-Liss, Inc. [source] Testing for Hysteresis in Unemployment in OECD Countries: New Evidence using Stationarity Panel Tests with Breaks,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 2 2006Mariam Camarero Abstract This paper tests hysteresis effects in unemployment using panel data for 19 Organization for Economic Co-operation and Development (OECD) countries covering the period 1956,2001. The tests exploit the cross-sectional variations of the series, and additionally, allow for a different number of endogenous breakpoints in the unemployment series. The critical values are simulated based on our specific panel sizes and time periods. The findings stress the importance of accounting for exogenous shocks in the series and support the natural-rate hypothesis of unemployment for the majority of the countries analysed. [source] Nitride-based quantum structures and devices on modified GaN substratesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2009Piotr Perlin Abstract We have studied the properties of InGaN layers and quantum wells grown on gallium nitride substrates with intentional surface misorientation with respect to its crystalline c -axis. Misorientation varied in the range from 0 up to 2 degree. The indium content was changed by using the different growth temperature (between 750 °C and 820 °C) during metalorganic vapor phase epitaxy. With increasing misorientation angle the average indium content decreased significantly. This effect was accompanied by the strong increase of the emission line bandwidth suggesting more pronounced indium segregation. The results of cathodoluminescence measurements show that these effects correspond to different number of atomic steps/terraces existing on the surface of gallium nitride substrate. Very interesting result is also demonstrated concerning p-type GaN layers. With increasing misorientation, the free hole density drastically increases above 1018 cm,3. This improvement in p-type doping is not related to the increased Mg concentration but to the reduction in the compensating donor density. Using this advantage we demonstrate nitride light emitters with improved electrical properties. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Degradation of Structural and Optical Properties of InGaN/GaN Multiple Quantum Wells with Increasing Number of WellsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2003S. Pereira Abstract We compare the structural and spectral properties of two multi quantum wells (MQWs), grown by metal organic chemical vapour deposition under the same nominal conditions, with a different number of periods. The MQWs, each with 20% InN and containing 8 and 18 wells, respectively, grew on-axis and coherent to GaN, as revealed by X-ray diffraction reciprocal space mapping (RSM) analysis. Comparison of the asymmetrical (105) RSMs indicates an overall structural deterioration and greater well-barrier intermixing for the MQW with the larger number of wells. Moreover, the composition of the MQWs was depth-profiled by grazing incidence Rutherford backscattering spectrometry (RBS). RBS further evidences strong intermixing in the 18-well heterostructure. The deleterious effects of intermixing on the emission spectrum are revealed by low temperature photoluminescence spectroscopy. Despite similar peak emission energies (,E < 45 meV) the 8-well structure shows a more symmetric and narrow peak (FWHM , 100 meV) in comparison with that of the 18-well sample (FWHM , 170 meV). Surface analyses by atomic force and scanning electron microscopy show an increased density, size and depth of V-pit defects on the 18-well structure. These results suggest that dislocations and pitting result from a larger elastic strain energy accumulated in the thicker MQW stack and are a fundamental intermixing mechanism for InGaN/GaN MQWs. [source] Enhanced Crystallinity of PTFE by Ion Irradiation in a Dense Plasma FocusPLASMA PROCESSES AND POLYMERS, Issue 2 2007Mehboob Sadiq Abstract Nitrogen-ion beam pulses emitted from a low-energy (1.45 kJ) Mather-type plasma focus device are used for the surface modification of PTFE polymer specimens. The specimens, placed at a fixed position, are implanted using different number of pulses. Raman spectroscopy and XRD are employed to probe the structural changes incurred during the ion implantation. Both techniques indicate that the crystalline order in the specimens increases with increasing the irradiation dose. The crystallinity degree of the irradiated specimens, as measured from the XRD data, is found to enhance monotonically from 40% to about 55%. Possible crystallinity enhancement mechanism of irradiated PTFE specimens via chain scission is discussed. [source] The Wilcoxon Signed Rank Test for Paired Comparisons of Clustered DataBIOMETRICS, Issue 1 2006Bernard Rosner Summary The Wilcoxon signed rank test is a frequently used nonparametric test for paired data (e.g., consisting of pre- and posttreatment measurements) based on independent units of analysis. This test cannot be used for paired comparisons arising from clustered data (e.g., if paired comparisons are available for each of two eyes of an individual). To incorporate clustering, a generalization of the randomization test formulation for the signed rank test is proposed, where the unit of randomization is at the cluster level (e.g., person), while the individual paired units of analysis are at the subunit within cluster level (e.g., eye within person). An adjusted variance estimate of the signed rank test statistic is then derived, which can be used for either balanced (same number of subunits per cluster) or unbalanced (different number of subunits per cluster) data, with an exchangeable correlation structure, with or without tied values. The resulting test statistic is shown to be asymptotically normal as the number of clusters becomes large, if the cluster size is bounded. Simulation studies are performed based on simulating correlated ranked data from a signed log-normal distribution. These studies indicate appropriate type I error for data sets with ,20 clusters and a superior power profile compared with either the ordinary signed rank test based on the average cluster difference score or the multivariate signed rank test of Puri and Sen (1971, Nonparametric Methods in Multivariate Analysis, New York: John Wiley). Finally, the methods are illustrated with two data sets, (i) an ophthalmologic data set involving a comparison of electroretinogram (ERG) data in retinitis pigmentosa (RP) patients before and after undergoing an experimental surgical procedure, and (ii) a nutritional data set based on a randomized prospective study of nutritional supplements in RP patients where vitamin E intake outside of study capsules is compared before and after randomization to monitor compliance with nutritional protocols. [source] In search for correlation among markers for limbal stem cells nicheACTA OPHTHALMOLOGICA, Issue 2009C CURCIO Purpose The corneoscleral limbus is known to be the site of corneal epithelial stem cells (SC). Several molecules have been proposed as SC markers but none of them is able to univocally identify them. The aim of this study was to evaluate co-expression of different SC markers in human limbus. Methods In this work five corneoscleral specimens from normal human donor eye-bank eyes (age 52-73 years) were fixed in formalin, divided in 8 segments, embedded in paraffin and examined by immunohistochemistry and immunofluorescence for p63, vimentin (vim), laminin 5, integrin (Int) ,6, Int ,1, Int ,4, connexin 43, ki67 and N-cadherin positivity. We firstly analyzed the distribution and the anatomical structure of limbal crypts in each of the segments. Then we evaluated the percentage of positive areas in the niches. Finally we looked for colocalizations and possible correlations among markers. Results We confirmed a different number of niches among the segments of the same corneoscleral rim. Moreover we observed high variability of niches number among patients which interestingly correlates with the percentage of p63 positivity of niche cells. Confocal microscopy double staining for p63 and vim did not show evident colocalization and vim + cells were seen in the superficial layers rather than in the deep layer of crypts. Int ,1 staining directly correlated with p63 positivity while the remaining proteins appeared variably and widely distributed Conclusion Colocalization was evident at least for two SC markers (Int ,1/p63) within the basal layers, while vim, expressed mainly in the superficial layers could act as late progenitor cell marker. [source] | ||||||||||||||||||||||||||||||||||||||||||||||