scholarly journals The Contingent Negative Variation: The Cumulative Curve Method Revisited

2017 ◽  
Author(s):  
Daniel Dumalin
Keyword(s):  
Contingent Negative Variation ◽  
Cumulative Curve ◽  
Curve Method

Contingent Negative Variation (CNV) bei Kindern mit hyperkinetischem Syndrom - eine experimentelle Untersuchung mittels des Continuous Performance Test (CPT)

2000 ◽  
Vol 28 (4) ◽  
pp. 239-246 ◽  
Author(s):  
K. Hennighausen ◽  
G. Schulte-Körne ◽  
A. Warnke ◽  
H. Remschmidt
Keyword(s):  
Contingent Negative Variation ◽  
Performance Test ◽  
Continuous Performance Test ◽  
Continuous Performance ◽  
Experimentelle Untersuchung

Zusammenfassung Fragestellung: Gibt es neurophysiologische Korrelate der Aufmerksamkeitsstörung beim hyperkinetischen Syndrom (HKS) und welche Bedeutung haben diese für die Ätiologie der Störung. Methodik: Selektive Aufmerksamkeitsprozesse wurden anhand des zweistufigen Continuous Performance Test (CPT) bei 18 Jungen mit hyperkinetischem Syndrom (HKS) untersucht und mit einer nach dem Alter parallelisierten Kontrollgruppe von 21 Jungen verglichen. Die Altersspanne der Stichprobe betrug 6 bis 12 Jahre. Parallel dazu wurden ereigniskorrelierte Potentiale (EKP) während des Tests an den Elektrodenpositionen Fz, Cz, Pz und Oz mit Referenz zu verbundenen Ohren abgeleitet. Ergebnisse: Im EKP nach dem präparatorischen Stimulus konnten zwei Komponenten der Contingent Negative Variation (CNV) mit unterschiedlicher topographischer Verteilung identifiziert werden (CNV-1: 600 bis 1100 ms und CNV-2: 1000 bis 1500 ms nach Stimulus). Die Stichproben unterschieden sich nicht auf der Verhaltensebene (Fehlerrate und Reaktionszeit). Signifikante Gruppenunterschiede ergaben sich hinsichtlich der Topographie der beiden CNV-Komponenten. Kinder mit HKS zeigten im Vergleich zu Kontrollkindern eine signifikant niedrigere CNV-1 über der frontalen und eine Tendenz zu stärkerer Negativierung (CNV-1 und CNV-2) über der occipitalen Elektrode. Schlussfolgerungen: Die Ergebnisse unterstützen die Hypothese einer Unterfunktion frontaler inhibitorischer Prozesse bei Kindern mit HKS.

A Comparative Analysis of Methods for Titering Reovirus

2020 ◽  
Vol 8 (5) ◽  
pp. 409-417
Author(s):  
Yi-Chen Yang ◽  
Xian-Yao Wang ◽  
Yuan-Yuan An ◽  
Chun-Xiang Liao ◽  
Nian-Xue Wang ◽  
...  
Keyword(s):  
Traditional Method ◽  
Virus Titer ◽  
Cell Analysis ◽  
Half Cell ◽  
L929 Cells ◽  
Cell Index ◽  
Standard Curve ◽  
Analysis Technique ◽  
Curve Method ◽  
Standard Curve Method

Background: A key challenge in the process of virus amplification is the need for a simple and convenient method for measuring virus titers. Objective: Real-time unlabeled cell analysis (RTCA) was used to establish a standard curve of correlation between half-cell index time (CIT50) and virus titer. At the same time, the virus titer from tunable resistance pulse detection (TRPS) technology was compared with the traditional median tissue culture infectious dose (TCID50) method to evaluate the feasibility and application value of the RTCA technique and TRPS technology. Methods: : Cell index (CI) values for L929 cells under different culture conditions were detected, and the appropriate initial cell inoculation density was screened. The half-cell index (CI50) values of reovirus infected L929 cells with TCID50 titers were analyzed by RTCA, the CI50-TCID50 standard curve was created, and a regression equation was developed. RTCA, TCID50, and TRPS methods were used to detect the reovirus titer obtained by the amplification, and the sensitivity and feasibility of the CIT50-TCID50 standard curve method were analyzed. The virus titer was detected by TRPS technology and the TCID50 method. Results: L929 cells were best propagated at an initial density of 6 × 103 cells/well. After infecting L929 cells with different titers of reference reovirus, the linear correlation of CIT50 and TCID50 was y = -2.1806x + 71.023 (R2 = 0.9742). The titer resulting from the RTCA assay was 7×109.6821 pfu/mL, from the TRPS assay was 4.52×1010 pfu/mL, and from the TCID50 assay was 7×109.467 pfu/mL. Conclusion: The CIT50-TCID50 standard curve method established by the RTCA technique can be used to quantitatively detect reovirus titer with L929 cells. Compared with the TCID50 method, it takes a relatively short time and has high sensitivity and accuracy. The TRPS technology requires even less time to quantify the virus, but its precision is lower than that of the TCID50 method and RTCA technology. This study provides new technical methods for assessing the virulence of infectious live reovirus particles. Lay Summary: After amplification of the virus, we need to detect the virus titers (the virulence of the virus). The traditional method is to use the virus to infect cells, and then the virus titers can be calculated by 50% of the cells infected. However, this traditional method is time consuming. The ways of RTCA (a real-time cell analysis technique) and TRPS (a nano-bioparticle analysis technique) help us to detect viral titers. The consistency of these three methods determines their feasibility and accuracy. If they are feasible, then these two simple technologies will provide new ideas for detecting viral titers.

Determination of alcohols in mixtures by 19F NMR spectroscopy using hexefluoroacetone reagent

1982 ◽  
Vol 47 (7) ◽  
pp. 1973-1978 ◽  
Author(s):  
Jiří Karhan ◽  
Zbyněk Ksandr ◽  
Jiřina Vlková ◽  
Věra Špatná
Keyword(s):  
Standard Deviation ◽  
Nmr Spectroscopy ◽  
Standard Method ◽  
Internal Standard ◽  
Internal Standard Method ◽  
Concentration Region ◽  
Experimental Conditions ◽  
Curve Method ◽  
Sample Preparation Procedure

The determination of alcohols by 19F NMR spectroscopy making use of their reaction with hexafluoroacetone giving rise to hemiacetals was studied on butanols. The calibration curve method and the internal standard method were used and the results were mutually compared. The effects of some experimental conditions, viz. the sample preparation procedure, concentration, spectrometer setting, and electronic integration, were investigated; the conditions, particularly the concentrations, proved to have a statistically significant effect on the results of determination. For the internal standard method, the standard deviation was 0.061 in the concentration region 0.032-0.74 mol l-1. The method was applied to a determination of alcohols in the distillation residue from an oxo synthesis.

Updating real‐time flood forecasts via the dynamic system response curve method

2015 ◽  
Vol 51 (7) ◽  
pp. 5128-5144 ◽  
Author(s):  
Wei Si ◽  
Weimin Bao ◽  
Hoshin V. Gupta
Keyword(s):  
Dynamic System ◽  
Real Time ◽  
Response Curve ◽  
System Response ◽  
Curve Method

scholarly journals Derivation of water flooding characteristic curve for offshore low-amplitude structural reservoir with strong bottom water

2021 ◽  
Author(s):  
Ying-xian Liu ◽  
Jie Tan ◽  
Hui Cai ◽  
Yan-lai Li ◽  
Chun-yan Liu
Keyword(s):  
Bottom Water ◽  
Characteristic Curve ◽  
Calculated Data ◽  
Oil Production ◽  
Water Flooding ◽  
Characteristic Curves ◽  
Recoverable Reserves ◽  
Curve Method ◽  
Water Cut ◽  
Low Amplitude

AbstractThe water flooding characteristic curve method is one of the essential techniques to predict recoverable reserves. However, the recoverable reserves indicated by the existing water flooding characteristic curves of low-amplitude reservoirs with strong bottom water increase gradually, and the current local recovery degree of some areas has exceeded the predicted recovery rate. The applicability of the existing water flooding characteristic curves in low-amplitude reservoirs with strong bottom water is lacking, which affects the accurate prediction of development performance. By analyzing the derivation process of the conventional water flooding characteristic curve method, this manuscript finds out the reasons for the poor applicability of the existing water flooding characteristic curve in low-amplitude reservoir with strong bottom water and corrects the existing water flooding characteristic curve according to the actual situation of the oilfield and obtains the improvement method of water flooding characteristic curve in low-amplitude reservoir with strong bottom water. After correction, the correlation coefficient between $$\frac{{k_{ro} }}{{k_{rw} }}$$ k ro k rw and $$S_{w}$$ S w is 95.92%. According to the comparison between the actual data and the calculated data, in 2021/3, the actual water cut is 97.29%, the water cut predicted by the formula is 97.27%, the actual cumulative oil production is 31.19 × 104t, and the predicted cumulative oil production is 31.31 × 104t. The predicted value is consistent with the actual value. It provides a more reliable method for predicting low-amplitude reservoirs' recoverable ability with strong bottom water and guides the oilfield's subsequent decision-making.

scholarly journals Computation of distribution of relaxation times by Tikhonov regularization for Li ion batteries: usage of L-curve method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Paul ◽  
P. W. Chi ◽  
Phillip M. Wu ◽  
M. K. Wu
Keyword(s):  
Tikhonov Regularization ◽  
Relaxation Times ◽  
Detection Methods ◽  
Similar Process ◽  
Fredholm Integral Equations ◽  
Li Ion Batteries ◽  
Impedance Data ◽  
Curve Method ◽  
Li Ion ◽  
Process Detection

AbstractIn this paper, the distribution of relaxation times (DRTs) functions are calculated numerically in Matlab for synthetic impedance data from single parallel $$RC$$ RC circuit and two parallel $$RC$$ RC circuits connected in series, experimental impedance data from supercapacitors and α-LiFeO2 anode based Li ion batteries. The quality of the impedance data is checked with the Kramers–Krönig (KK) relations. The DRTs are calculated within the KK compatible regime for all the systems using Tikhonov regularization (TR) method. Here we use a fast and simple L-curve method to estimate the TR parameter (λ) for regularization of the Fredholm integral equations of first kind in impedance. Estimation of the regularization parameters are performed effectively from the offset of the global corner of the L-curve rather than simply using the global corner. The physical significances of DRT peaks are also discussed by calculating the effective resistances and capacitances coupled with peak fitting program. For instance, two peaks in the DRTs justify the electrical double layer capacitance and ion diffusion phenomena for supercapacitors in low to intermediate frequencies respectively. Moreover, the surface film effect, Li/electrolyte and electrode/electrolyte charge transfer related processes are identified for α-LiFeO2 anode based Li-ion batteries. This estimation of the offset of the global corner extends the L-curve approach coupled with the Tikhonov regularization in the field of electrochemistry and can also be applied in similar process detection methods.

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