Constructing calibration curves for means of measurement by the maximum-compactness method

1987 ◽  
Vol 30 (7) ◽  
pp. 634-637
Author(s):  
A. P. Blinov
Keyword(s):  
Compactness Method ◽  
Calibration Curves ◽  
Means Of Measurement

Prognostic nomogram to predict overall survival for patients with perihilar cholangiocarcinoma: A population-based study of SEER database (Preprint)

2020 ◽  
Author(s):  
Chendong Wang
Keyword(s):  
Overall Survival ◽  
Prognostic Factors ◽  
Staging System ◽  
Tnm Staging ◽  
Survival Outcome ◽  
Perihilar Cholangiocarcinoma ◽  
Cox Regression Analysis ◽  
Calibration Curves ◽  
Tnm Staging System ◽  
Net Benefits

BACKGROUND Perihilar cholangiocarcinoma (pCCA) is a highly aggressive malignancy with poor prognosis. Accurate prediction is of great significance for patients’ survival outcome. OBJECTIVE The present study aimed to propose a prognostic nomogram for predicting the overall survival (OS) for patients with pCCA. METHODS We conducted a retrospective analysis in a total of 940 patients enrolled from the Surveillance, Epidemiology, and End Results (SEER) program and developed a nomogram based on the prognostic factors identified from the cox regression analysis. Concordance index (C-index), risk group stratification and calibration curves were adopted to test the discrimination and calibration ability of the nomogram with bootstrap method. Decision curves were also plotted to evaluate net benefits in clinical use against TNM staging system. RESULTS On the basis of multivariate analysis, five independent prognostic factors including age, summary stage, surgery, chemotherapy, together with radiation were selected and entered into the nomogram model. The C-index of the model was significantly higher than TNM system in the training set (0.703 vs 0.572, P<0.001), which was also proved in the validation set (0.718 vs 0.588, P<0.001). The calibration curves for 1-, 2-, and 3-year OS probabilities exhibited good agreements between the nomogram-predicted and the actual observation. Decision curves displayed that the nomogram obtained more net benefits than TNM staging system in clinical context. The OS curves of two distinct risk groups stratified by nomogram-predicted survival outcome illustrated statistical difference. CONCLUSIONS We established and validated an easy-to-use prognostic nomogram, which can provide more accurate individualized prediction and assistance in decision making for pCCA patients.

scholarly journals Simultaneous quantitation of five triazole anti-fungal agents by paper spray-mass spectrometry

2020 ◽  
Vol 58 (5) ◽  
pp. 836-846 ◽  
Author(s):  
Christine L. Skaggs ◽  
Greta J. Ren ◽  
El Taher M. Elgierari ◽  
Lillian R. Sturmer ◽  
Run Z. Shi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Therapeutic Drug ◽  
Reference Laboratory ◽  
Triple Quadrupole Mass Spectrometer ◽  
Limit Of Quantification ◽  
Paper Spray ◽  
Calibration Curves ◽  
Drug Concentrations ◽  
Limit Of Quantitation ◽  
Anti Fungal

AbstractBackgroundInvasive fungal disease is a life-threatening condition that can be challenging to treat due to pathogen resistance, drug toxicity, and therapeutic failure secondary to suboptimal drug concentrations. Frequent therapeutic drug monitoring (TDM) is required for some anti-fungal agents to overcome these issues. Unfortunately, TDM at the institutional level is difficult, and samples are often sent to a commercial reference laboratory for analysis. To address this gap, the first paper spray-mass spectrometry assay for the simultaneous quantitation of five triazoles was developed.MethodsCalibration curves for fluconazole, posaconazole, itraconazole, hydroxyitraconazole, and voriconazole were created utilizing plasma-based calibrants and four stable isotopic internal standards. No sample preparation was needed. Plasma samples were spotted on a paper substrate in pre-manufactured plastic cartridges, and the dried plasma spots were analyzed directly utilizing paper spray-mass spectrometry (paper spray MS/MS). All experiments were performed on a Thermo Scientific TSQ Vantage triple quadrupole mass spectrometer.ResultsThe calibration curves for the five anti-fungal agents showed good linearity (R2 = 0.98–1.00). The measured assay ranges (lower limit of quantification [LLOQ]–upper limit of quantitation [ULOQ]) for fluconazole, posaconazole, itraconazole, hydroxyitraconazole, and voriconazole were 0.5–50 μg/mL, 0.1–10 μg/mL, 0.1–10 μg/mL, 0.1–10 μg/mL, and 0.1–10 μg/mL, respectively. The inter- and intra-day accuracy and precision were less than 25% over the respective ranges.ConclusionsWe developed the first rapid paper spray-MS/MS assay for simultaneous quantitation of five triazole anti-fungal agents in plasma. The method may be a powerful tool for near-point-of-care TDM aimed at improving patient care by reducing the turnaround time and for use in clinical research.

scholarly journals Sensitivity Analysis of Single- and Bimetallic Surface Plasmon Resonance Biosensors

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4348
Author(s):  
Piotr Mrozek ◽  
Ewa Gorodkiewicz ◽  
Paweł Falkowski ◽  
Bogusław Hościło
Keyword(s):  
Refractive Index ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Real Life ◽  
Reflectance Measurement ◽  
Near Surface ◽  
Bimetallic Surface ◽  
Calibration Curves ◽  
Surface Sensing

Comparative analysis of the sensitivity of two surface plasmon resonance (SPR) biosensors was conducted on a single-metallic Au sensor and bimetallic Ag–Au sensor, using a cathepsin S sensor as an example. Numerically modeled resonance curves of Au and Ag–Au layers, with parameters verified by the results of experimental reflectance measurement of real-life systems, were used for the analysis of these sensors. Mutual relationships were determined between ∂Y/∂n components of sensitivity of the Y signal in the SPR measurement to change the refractive index n of the near-surface sensing layer and ∂n/∂c sensitivity of refractive index n to change the analyte’s concentration, c, for both types of sensors. Obtained results were related to experimentally determined calibration curves of both sensors. A characteristic feature arising from the comparison of calibration curves is the similar level of Au and Ag–Au biosensors’ sensitivity in the linear range, where the signal of the AgAu sensor is at a level several times greater. It was shown that the influence of sensing surface morphology on the ∂n/∂c sensitivity component had to be incorporated to explain the features of calibration curves of sensors. The shape of the sensory surface relief was proposed to increase the sensor sensitivity at low analyte concentrations.

scholarly journals DIFFERENCES IN CALIBRATION CURVES OF ANDROSTERONE AND DEHYDROISOANDROSTERONE

1941 ◽  
Vol 137 (1) ◽  
pp. 317-323
Author(s):  
Eleanor Saier ◽  
Mary Warga ◽  
Robert C. Grauer
Keyword(s):  
Calibration Curves

scholarly journals Quality Dating: A Well-Defined Protocol Implemented at ETH for High-Precision 14C-Dates Tested on Late Glacial Wood

Radiocarbon ◽  
2019 ◽  
Vol 62 (4) ◽  
pp. 891-899 ◽  
Author(s):  
Adam Sookdeo ◽  
Bernd Kromer ◽  
Ulf Büntgen ◽  
Michael Friedrich ◽  
Ronny Friedrich ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tree Ring ◽  
High Precision ◽  
Accelerator Mass Spectrometry ◽  
Late Glacial ◽  
Tree Ring Chronology ◽  
Continuous Measurements ◽  
Calibration Curves

ABSTRACTAdvances in accelerator mass spectrometry have resulted in an unprecedented amount of new high-precision radiocarbon (14C) -dates, some of which will redefine the international 14C calibration curves (IntCal and SHCal). Often these datasets are unaccompanied by detailed quality insurances in place at the laboratory, questioning whether the 14C structure is real, a result of a laboratory variation or measurement-scatter. A handful of intercomparison studies attempt to elucidate laboratory offsets but may fail to identify measurement-scatter and are often financially constrained. Here we introduce a protocol, called Quality Dating, implemented at ETH-Zürich to ensure reproducible and accurate high-precision 14C-dates. The protocol highlights the importance of the continuous measurements and evaluation of blanks, standards, references and replicates. This protocol is tested on an absolutely dated German Late Glacial tree-ring chronology, part of which is intercompared with the Curt Engelhorn-Center for Archaeometry, Mannheim, Germany (CEZA). The combined dataset contains 170 highly resolved, highly precise 14C-dates that supplement three decadal dates spanning 280 cal. years in IntCal, and provides detailed 14C structure for this interval.

scholarly journals The Means of Measurement

1966 ◽  
Vol 59 (3) ◽  
pp. 237-250
Author(s):  
Hedley Atkins
Keyword(s):  
Means Of Measurement

scholarly journals Luminosity Calibration of Giants and Supergiants, G0–M5

1973 ◽  
Vol 54 ◽  
pp. 68-77
Author(s):  
Ph. C. Keenan
Keyword(s):  
Calibration Curves ◽  
Hr Diagram

Calibration curves giving Mv for stars of luminosity classes III, II, Ib, Iab and 0 are derived and shown graphically in the HR diagram. There are serious gaps in which the calibration needs to be improved.

Estimation of the reliability in checking means of measurement

1982 ◽  
Vol 25 (5) ◽  
pp. 377-379
Author(s):  
A. A. Tsibina ◽  
S. B. Danilevich
Keyword(s):  
Means Of Measurement

SEC/MALDI-TOF Mass spectrometry study of hydroxy-, carboxy- and methyl ester-terminated aliphatic polyesters

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Slim Salhi ◽  
Martine Tessier ◽  
Jean-Claude Blais ◽  
Rachid El Gharbi ◽  
Alain Fradet
Keyword(s):  
Dimethyl Ester ◽  
Calibration Method ◽  
Size Exclusion ◽  
Aliphatic Polyesters ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Calibration Curves ◽  
End Groups ◽  
Poly Ethylene ◽  
Tof Ms

AbstractPoly(ethylene adipate) (PEA) and poly(ethylene dodecanedioate) (PED) with dicarboxy-, dihydroxy-, dimethyl ester- and hydroxy-carboxy end-groups were synthesized and characterized by 13C NMR and MALDI-TOF MS. Size-exclusion chromatography (SEC) fractions of these polyesters were analyzed by MALDI-TOF MS and used as standards to obtain SEC calibration curves leading to the absolute molar masses of the unfractionated polyesters. PEA and PED calibration curves were different from each other, but the same calibration curve was obtained for each type of polyester, irrespective of the nature of end-groups, showing the predominant role of the nature of repeating units on the hydrodynamic volume of oligoesters. The study also shows that the conventional SEC calibration method using polystyrene standards leads to a significant overestimation of polyester average molar masses.

Sign in / Sign up

Export Citation Format

Share Document