scholarly journals Gas Chromatographic Fingerprint Analysis for the Comparison of Seized Cannabis Samples

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6643
Author(s):  
Amorn Slosse ◽  
Filip Van Durme ◽  
Nele Samyn ◽  
Debby Mangelings ◽  
Yvan Vander Heyden
Keyword(s):  
Error Rate ◽  
Reference Data ◽  
Cannabis Sativa ◽  
Pearson Correlation ◽  
False Negative ◽  
Chromatographic Fingerprint ◽  
Root Transformation ◽  
Fourth Root ◽  
Pre Treatment ◽  
Fingerprint Alignment

Cannabis sativa L. is widely used as recreational illegal drugs. Illicit Cannabis profiling, comparing seized samples, is challenging due to natural Cannabis heterogeneity. The aim of this study was to use GC–FID and GC–MS herbal fingerprints for intra (within)- and inter (between)-location variability evaluation. This study focused on finding an acceptable threshold to link seized samples. Through Pearson correlation-coefficient calculations between intra-location samples, ‘linked’ thresholds were derived using 95% and 99% confidence limits. False negative (FN) and false positive (FP) error rate calculations, aiming at obtaining the lowest possible FP value, were performed for different data pre-treatments. Fingerprint-alignment parameters were optimized using Automated Correlation-Optimized Warping (ACOW) or Design of Experiments (DoE), which presented similar results. Hence, ACOW data, as reference, showed 54% and 65% FP values (95 and 99% confidence, respectively). An additional fourth root normalization pre-treatment provided the best results for both the GC–FID and GC–MS datasets. For GC–FID, which showed the best improved FP error rate, 54 and 65% FP for the reference data decreased to 24 and 32%, respectively, after fourth root transformation. Cross-validation showed FP values similar as the entire calibration set, indicating the representativeness of the thresholds. A noteworthy improvement in discrimination between seized Cannabis samples could be concluded.

scholarly journals Prospective Study Comparing Deep Throat Saliva With Other Respiratory Tract Specimens in the Diagnosis of Novel Coronavirus Disease 2019

2020 ◽  
Vol 222 (10) ◽  
pp. 1612-1619 ◽  
Author(s):  
Christopher K C Lai ◽  
Zigui Chen ◽  
Grace Lui ◽  
Lowell Ling ◽  
Timothy Li ◽  
...  
Keyword(s):  
Prospective Study ◽  
Pearson Correlation ◽  
False Negative ◽  
False Negative Rate ◽  
Productive Cough ◽  
Rt Pcr ◽  
Virus Shedding ◽  
Positive Rate ◽  
Novel Coronavirus ◽  
Rna Concentration

Abstract Background Self-collected specimens have been advocated to avoid infectious exposure to healthcare workers. Self-induced sputum in those with a productive cough and saliva in those without a productive cough have been proposed, but sensitivity remains uncertain. Methods We performed a prospective study in 2 regional hospitals in Hong Kong. Results We prospectively examined 563 serial samples collected during the virus shedding periods of 50 patients: 150 deep throat saliva (DTS), 309 pooled-nasopharyngeal (NP) and throat swabs, and 104 sputum. Deep throat saliva had the lowest overall reverse-transcriptase polymerase chain reaction (RT-PCR)-positive rate (68.7% vs 89.4% [sputum] and 80.9% [pooled NP and throat swabs]) and the lowest viral ribonucleic acid (RNA) concentration (mean log copy/mL 3.54 vs 5.03 [sputum] and 4.63 [pooled NP and throat swabs]). Analyses with respect to time from symptom onset and severity also revealed similar results. Virus yields of DTS correlated with that of sputum (Pearson correlation index 0.76; 95% confidence interval, 0.62–0.86). We estimated that the overall false-negative rate of DTS could be as high as 31.3% and increased 2.7 times among patients without sputum. Conclusions Deep throat saliva produced the lowest viral RNA concentration and RT-PCR-positive rate compared with conventional respiratory specimens in all phases of illness. Self-collected sputum should be the choice for patients with sputum.

scholarly journals “Missed” Mild Cognitive Impairment: High False-Negative Error Rate Based on Conventional Diagnostic Criteria

2016 ◽  
Vol 52 (2) ◽  
pp. 685-691 ◽  
Author(s):  
Emily C. Edmonds ◽  
Lisa Delano-Wood ◽  
Amy J. Jak ◽  
Douglas R. Galasko ◽  
David P. Salmon ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Diagnostic Criteria ◽  
Error Rate ◽  
False Negative ◽  
Negative Error ◽  
False Negative Error

Errors in prostate core biopsy diagnosis in an era of specialisation and double reporting

2020 ◽  
pp. jclinpath-2020-206726
Author(s):  
Cornelia Margaret Szecsei ◽  
Jon D Oxley
Keyword(s):  
Error Rate ◽  
False Positive ◽  
Core Biopsy ◽  
False Negative ◽  
Diagnostic Error ◽  
Error Rates ◽  
False Positive Error ◽  
Biopsy Diagnosis ◽  
False Negative Error ◽  
False Positive Error Rate

AimTo examine the effects of specialist reporting on error rates in prostate core biopsy diagnosis.MethodBiopsies were reported by eight specialist uropathologists over 3 years. New cancer diagnoses were double-reported and all biopsies were reviewed for the multidisciplinary team (MDT) meeting. Diagnostic alterations were recorded in supplementary reports and error rates were compared with a decade previously.Results2600 biopsies were reported. 64.1% contained adenocarcinoma, a 19.7% increase. The false-positive error rate had reduced from 0.4% to 0.06%. The false-negative error rate had increased from 1.5% to 1.8%, but represented fewer absolute errors due to increased cancer incidence.ConclusionsSpecialisation and double-reporting have reduced false-positive errors. MDT review of negative cores continues to identify a very low number of false-negative errors. Our data represents a ‘gold standard’ for prostate biopsy diagnostic error rates. Increased use of MRI-targeted biopsies may alter error rates and their future clinical significance.

Errors in identification using natural markings: rates, sources, and effects on capture–recapture estimates of abundance

2001 ◽  
Vol 58 (9) ◽  
pp. 1861-1870 ◽  
Author(s):  
Peter T Stevick ◽  
Per J Palsbøll ◽  
Tim D Smith ◽  
Mark V Bravington ◽  
Philip S Hammond
Keyword(s):  
Error Rate ◽  
Large Scale ◽  
False Negative ◽  
Parametric Bootstrap ◽  
Humpback Whales ◽  
The North ◽  
Abundance Estimates ◽  
Capture Recapture ◽  
Quality Rating ◽  
Estimation Of Variance

The results of a double-marking experiment using natural markings and microsatellite genetic markers to identify humpback whales (Megaptera novaeangliae) confirm that natural markings are a reliable means of identifying individuals on a large scale. Of 1410 instances of double tagging, there were 414 resightings. No false positive and 14 false negative errors were identified. The rate of error increased with decreasing photographic quality; no errors were observed among photographs of the highest quality rating, whereas an error rate of 0.125 was identified in sightings for which only part of the area used for identification was visible. There was also a weaker relationship between error rate and the distinctiveness of markings, which may result from non-independence in coding for image quality and distinctiveness. A correction is developed for the Petersen two-sample abundance estimator to account for false negative errors in identification, and a parametric bootstrap procedure for estimation of variance is also developed. In application to abundance estimates from the North Atlantic, the correction reduces the bias in estimates made using poorer quality photographs to a negligible level while maintaining comparable precision.

scholarly journals Machine Learning Assisted Cervical Cancer Detection

2021 ◽  
Vol 9 ◽  
Author(s):  
Mavra Mehmood ◽  
Muhammad Rizwan ◽  
Michal Gregus ml ◽  
Sidra Abbas
Keyword(s):  
Machine Learning ◽  
Cervical Cancer ◽  
Mean Squared Error ◽  
Medical Center ◽  
Pearson Correlation ◽  
False Negative ◽  
Hybrid Approach ◽  
False Negative Rate ◽  
Machine Learning Algorithms ◽  
Screening Programs

Cervical malignant growth is the fourth most typical reason for disease demise in women around the globe. Cervical cancer growth is related to human papillomavirus (HPV) contamination. Early screening made cervical cancer a preventable disease that results in minimizing the global burden of cervical cancer. In developing countries, women do not approach sufficient screening programs because of the costly procedures to undergo examination regularly, scarce awareness, and lack of access to the medical center. In this manner, the expectation of the individual patient's risk becomes very high. There are many risk factors relevant to malignant cervical formation. This paper proposes an approach named CervDetect that uses machine learning algorithms to evaluate the risk elements of malignant cervical formation. CervDetect uses Pearson correlation between input variables as well as with the output variable to pre-process the data. CervDetect uses the random forest (RF) feature selection technique to select significant features. Finally, CervDetect uses a hybrid approach by combining RF and shallow neural networks to detect Cervical Cancer. Results show that CervDetect accurately predicts cervical cancer, outperforms the state-of-the-art studies, and achieved an accuracy of 93.6%, mean squared error (MSE) error of 0.07111, false-positive rate (FPR) of 6.4%, and false-negative rate (FNR) of 100%.

scholarly journals Comparison of 4 Screening Methods for Detecting Fluoropyrimidine Toxicity Risk: Identification of the Most Effective, Cost-Efficient Method to Save Lives

Dose-Response ◽  
2020 ◽  
Vol 18 (3) ◽  
pp. 155932582095136
Author(s):  
Olivier Capitain ◽  
Valérie Seegers ◽  
Jean-Philippe Metges ◽  
Roger Faroux ◽  
Claire Stampfli ◽  
...  
Keyword(s):  
Dihydropyrimidine Dehydrogenase ◽  
Parametric Method ◽  
False Negative ◽  
Cost Effective ◽  
Risk Identification ◽  
Screening Methods ◽  
Risk Of Death ◽  
Toxicity Risk ◽  
Pre Treatment ◽  
Screening Approaches

Background: Fluoropyrimidines (FPs) carry around 20% risk of G3-5 toxicity and 0.2-1% risk of death, due to dihydropyrimidine dehydrogenase (DPD) deficiency. Several screening approaches exist for predicting toxicity, however there is ongoing debate over which method is best. This study compares 4 screening approaches. Method: 472 patients treated for colorectal, head-and-neck, breast, or pancreatic cancers, who had not been tested pre-treatment for FP toxicity risk, were screened using: DPYD genotyping (G); phenotyping via plasma Uracil (U); phenotyping via plasma-dihydrouracil/uracil ratio (UH2/U); and a Multi-Parametric Method (MPM) using genotype, phenotype, and epigenetic data. Performance was compared, particularly the inability to detect at-risk patients (false negatives). Results: False negative rates for detecting G5 toxicity risk were 51.2%, 19.5%, 9.8% and 2.4%, for G, U, UH2/U and MPM, respectively. False negative rates for detecting G4-5 toxicity risk were 59.8%, 36.1%, 21.3% and 4.7%, respectively. MPM demonstrated significantly (p < 0.001) better prediction performance. Conclusion: MPM is the most effective method for limiting G4-5 toxicity. Its systematic implementation is cost-effective and significantly improves the risk-benefit ratio of FP-treatment. The use of MPM, rather than G or U testing, would avoid nearly 8,000 FP-related deaths per year globally (500 in France), and spare hundreds of thousands from G4 toxicity.

Comparison of Performance of Conventional and ThinPrep Gynecologic Preparations in the College of American Pathologists Gynecologic Cytology Program

2004 ◽  
Vol 128 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Andrew A. Renshaw ◽  
Nancy A. Young ◽  
George G. Birdsong ◽  
Patricia E. Styer ◽  
Diane D. Davey ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Error Rate ◽  
False Negative ◽  
Error Rates ◽  
High Grade ◽  
Squamous Intraepithelial Lesion ◽  
Exact Match ◽  
Intraepithelial Lesion

Abstract Context.—Results of clinical trials suggest that interpretation of liquid-based cytology preparations is more accurate and is associated with less screening error than interpretation of conventional preparations. Objective.—In this study, the performance of participants in interpreting ThinPrep (TP) preparations was compared with participants' performance on conventional Papanicolaou tests in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology (PAP). Design.—The results of the PAP from the year 2002 were reviewed, and the discordancies to series and exact-match error rates for the 2 cytologic methods were compared. Results.—For this study, a total of 89 815 interpretations from conventional smears and 20 886 interpretations from TP samples were analyzed. Overall, interpretations of TP preparations had both significantly fewer false-positive (1.6%) and false-negative (1.3%) rates than those of conventional smears (P = .001 and P = .02, respectively) for validated or validated-equivalent slides, as assessed by concordance with the correct diagnostic series. In this assessment of concordance to series, interpretations of educational TP and conventional preparations were similar, except for high-grade squamous intraepithelial lesion, in which the performance was significantly worse for educational TP preparations (false-negative rate of 8.1% vs 4.1% for conventional smears, P &lt; .001). When interpretations were matched to the exact diagnosis, validated-equivalent TP preparations were generally more accurate for diagnoses in the 100 series and 200 series than were conventional smears. Notably, for the reference diagnosis of squamous cell carcinoma, the exact-match error rate on validated equivalent TP slides was significantly greater than that of conventional slides (44.5% vs 23.1%, P &lt; .001). Interpretations of educational TP preparations also had a significantly higher error rate in matching to the exact reference diagnosis for squamous cell carcinoma (33.7% vs 22.8%, P = .007). Conclusions.—Overall, TP preparations in this program were associated with significantly lower error rates than conventional smears for both validated and educational cases. However, unlike the negative for intraepithelial lesion and malignancy, not otherwise specified, low-grade squamous intraepithelial lesion, and adenocarcinoma cytodiagnostic challenges, participants' responses indicated some difficulty in recognizing high-grade squamous intraepithelial lesion and squamous cell carcinoma.

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