scholarly journals Multi-lab intrinsic solubility measurement reproducibility in CheqSol and shake-flask methods

ADMET & DMPK ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 210-219 ◽  
Author(s):  
Alex Avdeef
Keyword(s):  
Standard Deviation ◽  
Gold Standard ◽  
Shake Flask ◽  
Systematic Errors ◽  
White Paper ◽  
Training Set ◽  
Solubility Measurement ◽  
Correlation Plot ◽  
Measurement Methodology ◽  
Intrinsic Solubility

This commentary compares 233 CheqSol intrinsic solubility values (log S0) reported in the Wiki-pS0 database for 145 different druglike molecules to the 838 log S0 values determined mostly by the saturation shake-flask (SSF) method for 124 of the molecules from the CheqSol set. The range of log S0 spans from -1.0 to -10.6 (log molar units), averaging at -3.8. The correlation plot between the two methods indicates r2 = 0.96, RMSE = 0.34 log unit, and a slight bias of -0.07 log unit. The average interlaboratory standard deviation (SDi) is slightly better for the CheqSol set than that of the SSF set: SDiCS = 0.15 and SDiSSF = 0.24. The intralaboratory errors reported in the CheqSol method (0.05 log) need to be multiplied by a factor of 3 to match the expected interlaboratory errors for the method. The scale factor, in part, relates to the hidden systematic errors in the single-lab values. It is expected that improved standardizations in the ‘gold standard’ SSF method, as suggested in the recent ‘white paper’ on solubility measurement methodology, should make the SDi of both methods be about ~0.15 log unit. The multi-lab averaged log S0 (and the corresponding SDi) values could be helpful additions to existing training-set molecules used to predict the intrinsic solubility of drugs and druglike molecules.

ON THE COMPARISON OF NN-BASED ARCHITECTURES FOR DIABETIC DAMAGE DETECTION IN RETINAL IMAGES

2009 ◽  
Vol 18 (08) ◽  
pp. 1369-1380 ◽  
Author(s):  
VITOANTONIO BEVILACQUA ◽  
LEONARDA CARNIMEO ◽  
GIUSEPPE MASTRONARDI ◽  
VITO SANTARCANGELO ◽  
ROCCO SCARAMUZZI
Keyword(s):  
Neural Network ◽  
Damage Detection ◽  
Gold Standard ◽  
Retinal Images ◽  
Neural Net ◽  
Early Prevention ◽  
Training Set ◽  
Binary Images ◽  
Contrast Enhanced ◽  
Fundus Oculi

The automatic screening of retinal images for an early detection of diabetic symptoms and an early prevention of diabetic retinopathies has been a prime focus in recent times. In this paper a contribution to improve diabetic damage detection in retinal images via neural networks is proposed by comparing two neural strategies. By considering the first architecture, fundus oculi symptomatic pale regions are firstly highlighted by enhancing image contrast with a neurofuzzy subnet, which is synthesized using a Sparsely-Connected Neural Network. Then, obtained contrast-enhanced images with bimodal histograms are globally segmented, after an optimal thresholding performed by a neural subsystem. In output binary images, suspect diabetic areas are finally isolated. By considering the second architecture, an EBP MLP neural net is synthesized, where a suitable training set of suspect patterns is developed by (5 × 5) windows centered on damaged pixels in gold standard images provided by clinicians. Performances are evaluated by percentage measures of exactness in the detection of suspect damaged areas via a comparison with gold standard images provided by clinicians. Results of both strategies are discussed and compared with other researchers' ones.

scholarly journals Photometric redshifts for the Pan-STARRS1 survey

2020 ◽  
Vol 642 ◽  
pp. A102 ◽  
Author(s):  
P. Tarrío ◽  
S. Zarattini
Keyword(s):  
Standard Deviation ◽  
Photometric Data ◽  
Local Linear Regression ◽  
Training Set ◽  
Colour Space ◽  
Photometric Redshifts ◽  
Additional Advantage ◽  
Robust Approach ◽  
Photometric Redshift ◽  
Data Release

We present a robust approach to estimating the redshift of galaxies using Pan-STARRS1 photometric data. Our approach is an application of the algorithm proposed for the SDSS Data Release 12. It uses a training set of 2 313 724 galaxies for which the spectroscopic redshift is obtained from SDSS, and magnitudes and colours are obtained from the Pan-STARRS1 Data Release 2 survey. The photometric redshift of a galaxy is then estimated by means of a local linear regression in a 5D magnitude and colour space. Our approach achieves an average bias of Δ̅z̅n̅o̅r̅m̅ = −1.92 × 10−4, a standard deviation of σ(Δznorm) = 0.0299, and an outlier rate of Po = 4.30% when cross-validating the training set. Even though the relation between each of the Pan-STARRS1 colours and the spectroscopic redshifts is noisier than for SDSS colours, the results obtained by our approach are very close to those yielded by SDSS data. The proposed approach has the additional advantage of allowing the estimation of photometric redshifts on a larger portion of the sky (∼3/4 vs ∼1/3). The training set and the code implementing this approach are publicly available at the project website.

scholarly journals Clinical performance of lung ultrasound in predicting ARDS morphology

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Costamagna ◽  
Emanuele Pivetta ◽  
Alberto Goffi ◽  
Irene Steinberg ◽  
Pietro Arina ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Gold Standard ◽  
Diagnostic Performance ◽  
Lung Ultrasound ◽  
Clinical Performance ◽  
Training Set ◽  
Mechanically Ventilated ◽  
Validation Set ◽  
Lung Ct ◽  
B Lines

Abstract Background To assess diagnostic performance of lung ultrasound (LUS) in identifying ARDS morphology (focal vs non-focal), compared with the gold standard computed tomography. Methods Mechanically ventilated ARDS patients undergoing lung computed tomography and ultrasound were enrolled. Twelve fields, were evaluated. LUS score was graded from 0 (normal) to 3 (consolidation) according to B-lines extent. Total and regional LUS score as the sum of the four ventral (LUSV), intermediate (LUSI) or dorsal (LUSD) fields, were calculated. Based on lung CT, ARDS morphology was defined as (1) focal (loss of aeration with lobar distribution); (2) non-focal (widespread loss of aeration or segmental loss of aeration distribution associated with uneven lung attenuation areas), and diagnostic accuracy of LUS in discriminating ARDS morphology was determined by AU-ROC in training and validation set of patients. Results Forty-seven patients with ARDS (25 training set and 22 validation set) were enrolled. LUSTOT, LUSV and LUSI but not LUSD score were significantly lower in focal than in non-focal ARDS morphologies (p < .01). The AU-ROC curve of LUSTOT, LUSV, LUSI and LUSD for identification of non-focal ARDS morphology were 0.890, 0.958, 0.884 and 0.421, respectively. LUSV value ≥ 3 had the best predictive value (sensitivity = 0.95, specificity = 1.00) in identifying non-focal ARDS morphology. In the validation set, an LUSV score ≥ 3 confirmed to be highly predictive of non-focal ARDS morphology, with a sensitivity and a specificity of 94% and 100%. Conclusions LUS had a valuable performance in distinguishing ARDS morphology.

Value of Scatter-Graphs for the Assessment of ECG Computer Measurement Results

1990 ◽  
Vol 29 (04) ◽  
pp. 413-423 ◽  
Author(s):  
P. Rubel ◽  
J. L. Willems ◽  
D. Morlet
Keyword(s):  
Standard Deviation ◽  
Performance Assessment ◽  
Gold Standard ◽  
Evaluation Method ◽  
New Method ◽  
Main Program ◽  
Measurement Study ◽  
Point Estimates ◽  
Computer Measurement ◽  
Measurement Results

AbstractA new method is presented, different from usual methods, for the discussion of the results of computer ECG measurement programs, based on a new graphical evaluation method. The proposed “scatter-graphs” both highlight the main program results and facilitate the comparison between various wave-recognition algorithms. They allow the distinction between the reliability of an algorithm, which is its capacity to provide a maximum of measurements with a minimum amount of errors, and its precision, i.e., the standard deviation of the differences between its point estimates and the reference.The method proves to be a powerful tool for the discussion of individual, as well as the median program results in CSE Measurement Study. It allows to highlight limitations induced in performance assessment by the variability of the reference itself, and to state that the median program is at least as close to the “Gold Standard” as the median of the referees.

scholarly journals Comparing blood pressure measurements between a photoplethysmography-based and a standard cuff-based manometry device

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dean Nachman ◽  
Yftach Gepner ◽  
Nir Goldstein ◽  
Eli Kabakov ◽  
Arik Ben Ishay ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Standard Deviation ◽  
Gold Standard ◽  
Pressure Measurements ◽  
Study Analysis ◽  
High Agreement ◽  
Interclass Correlation Coefficient ◽  
Interclass Correlation ◽  
Males And Females ◽  
The Mean

Abstract Repeated blood pressure (BP) measurements allow better control of hypertension. Current measurements rely on cuff-based devices. The aim of the present study was to compare BP measurements using a novel cuff-less photoplethysmography-based device to a standard sphygmomanometer device. Males and females were recruited from within the general population who arrived at a public BP screening station. One to two measurements were taken from each using a sphygmomanometer-based and the photoplethysmography-based devices. Devices were considered equal if the mean difference between paired measurements was below 5 mmHg and the Standard Deviation (SD) was no greater than 8 mmHg. Agreement and reliability analyses were also performed. 1057 subjects were included in the study analysis. There were no adverse events during the study. The mean (± SD) difference between paired measurements for all subjects was -0.1 ± 3.6 mmHg for the systolic and 0.0 ± 3.5 mmHg for the diastolic readings. We found 96.31% agreement in identifying hypertension and an Interclass Correlation Coefficient of 0.99 and 0.97 for systolic and diastolic measurements, respectively. The photoplethysmography-based device was found similar to the gold-standard sphygmomanometer-based device with high agreement and reliability levels. The device might enable a reliable, more convenient method for repeated BP monitoring.

Gas-Liquid Chromatographic Determination of Bromoxynil Octanoate: Collaborative Study

1979 ◽  
Vol 62 (6) ◽  
pp. 1215-1219
Author(s):  
Laurence J Helfant ◽  
◽  
J Audino ◽  
G S Grimes ◽  
J J Karr ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Systematic Errors ◽  
Elution Time ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The assay of bromoxynil octanoate by a gasliquid chromatographic (GLC) procedure with din-n-butylphthalate as the internal standard was previously subjected to collaboration. The method had a standard deviation of 0.6% but results varied according to the complexity of the formulaation being tested. To reduce the systematic errors of the method, the internal standard was changed to n-docosane. The change in elution time of the marker simplified the chromatogram and reduced the standard deviation of the study to 0.3%. The revised method has been adopted as official first action for determining bromoxynil octanoate.

Diagnostic Accuracy of Stop-Bang Questionnaire in Diagnosing High Risk Patients of Obstructive Sleep Apnea Considering Polysomnography as a Gold Standard

2021 ◽  
Vol 15 (10) ◽  
pp. 2823-2825
Author(s):  
Masood uz Zaman Babar ◽  
Rizwan Ali Tunio ◽  
Sunil Dat Maheshwari ◽  
Ali Hassan ◽  
Hasham Masood Qureshi
Keyword(s):  
Obstructive Sleep Apnea ◽  
Standard Deviation ◽  
Sleep Apnea ◽  
High Risk ◽  
Diagnostic Accuracy ◽  
Predictive Value ◽  
Gold Standard ◽  
High Risk Patients ◽  
Obstructive Sleep ◽  
Risk Patients

Objective: To determine the diagnostic accuracy of stop-bang questionnaire to diagnose high risk patients of obstructive sleep apnea taking polysomnography as gold standard. Methodology: This cross-sectional descriptive study was conducted at Isra University Hospital Hyderabad and help taken from Sleep Disorder Laboratory, The Aga Khan Hospital, Karachi. Patients with age of 18 to 70 years, presenting with symptoms of OSA of either gender were included. History was taken from patients. STOP- BANG Questionnaire was filled out for each patient consenting to participate in the study. All information was noted and entered in the Proforma. Results: Mean age of patients was 40.1 with standard deviation 17.6, mean AHI score was 20 with standard deviation 6 and stop bang score showed average 6.8 with standard deviation 2.7. Distribution of gender showed that most of the patients were male. Diagnostic accuracy calculated for stop bang questionnaire, sensitivity 77.2%, Specificity 65.5%, Positive Predictive Value 75.4%, Negative Predictive Value 67.8%, Diagnostic Accuracy 72.3% of stop bang questionnaire as follows. Conclusion: This study confirms the STOP-Bang questionnaire's high performance in screening for Obstructive sleep apnea (OSA) in the surgical population and sleep clinic. The likelihood of OSA severity increases from moderate to severe with the increasing STOP-Bang score. Keywords: Obstructive sleep apnea, stop-bang questionnaire, apnea-hypopnea index, polysomnogram

Classification Algorithm Based on Categorical Data Analysis

2013 ◽  
Vol 333-335 ◽  
pp. 1292-1295
Author(s):  
Yu Sheng Cheng ◽  
Xiang Li ◽  
Mei Wen Ding
Keyword(s):  
Data Analysis ◽  
Standard Deviation ◽  
Mathematical Expectation ◽  
Categorical Data ◽  
Classification Algorithm ◽  
Categorical Data Analysis ◽  
Training Set ◽  
Shortest Distance ◽  
Category Comparison ◽  
Distance Category

Through compares three methods of Standard Deviation mathematical expectation and variance, a classification algorithm based on the Standard Deviation which in the training set is proposed in this paper. The algorithm first mapped the discrete attribute values to the corresponding values, and calculates Standard Deviation, mathematical expectation and Variance of each attribute in each category. The Standard Deviation, mathematical expectation and Variance of each attribute in each category used as coordinates. When there are new datas need to determine the category, we just need to use the attributes of the new data as coordinates, and calculate its distance to each category, and then the data type is the shortest distance category. Comparison of three methods, the Standard Deviation is the most stable and most accurate. This algorithm has advantages in dealing with the noisy date.

scholarly journals Solubility of Nifedipine by Shake Flask UV-Spectrometry; Review of Safety Concerns in Pregnancy

2021 ◽  
Vol 14 (4) ◽  
pp. 1823-1829
Author(s):  
Soham Samajpaty
Keyword(s):  
Chemical Analysis ◽  
Calcium Channel ◽  
Calcium Channel Blocker ◽  
Gold Standard ◽  
Shake Flask ◽  
Channel Blocker ◽  
Recent Past ◽  
Uv Spectrometry ◽  
Dihydropyridine Derivative ◽  
In Pregnancy

Nifedipine is chemically dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, a dihydropyridine derivative used frequently as anti-hypertensive. It is a L- type calcium channel blocker (CCB). Few analogical discrepancies were found between Nifedipine’s clinical output report and chemical analysis of solubility. The ambition of this research is to conduct a re-check and proper quantification of partition co-efficient (logP) of Nifedipine and clarify the discrepancy and rectify if any mistake has been done in recent past. The method used is the “gold standard” shake-flask method followed by analysis through UV-scpectrophotmetry.

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