Total Error Research Articles

A-225 Validation of self-collected capillary dried plasma spot collection for lipoprotein(a) testing

Abstract Background Cardiovascular disease is prominent among socially disadvantaged populations that do not have the resources for standard health screening. Self-collected capillary Advance Dx (ADX) dried plasma spot cards could address these issues by offering access to clinically acceptable lipid screening from remote collections. Our laboratory currently uses ADX specimens to screen for cholesterol, calculated LDL, HDL, glucose, lipoprotein (a) (LP(a)), and triglycerides, however, the current study will focus on the validation of self-collected capillary ADX specimens for LP(a) testing. Methods ADX LP(a) was measured using the Tina-quant Lipoprotein (a) Gen.2 assay on the Roche cobas c702 closed development channel. All closed development channel assay parameters followed the standard assay, except sample volume increased from 2 to 18uL. Calibration was performed using Roche LP(a) calibrators diluted 1:10 with water. Patient specimens were prepared by collecting four 6mm punches from the plasma portion of the ADX card. Samples were resuspended in 400uL of 0.1% bovine serum albumin and incubated for 30 minutes at room temperature (RT) while shaking at 250 RPM. Non-biological materials were diluted 1:13 with water to match the sample-to-diluent ratio of the extracted patient ADX specimens. A correction factor (CF) was derived and challenged using total protein (TP) as an internal standard. BioRad Lipids Control (BRLC) and ADX patient specimens were run for wet and dry matrices to establish imprecision. Accuracy was determined using BRLC and ADX patient specimens. Linearity was confirmed by running 5 levels of Maine Standards Linearity Cardiac CM3 Kit. ADX stability was observed at RT and under summer/winter conditions to account for shipping to the laboratory. Results Specimens tested between venous and ADX LP(a) to derive the CF (n=70) had a bias of 21.92 mg/dL (132.28%) and a linear equation of (y=2.40x -1.23; R=0.985). Average card TP was 4.36 g/dL. The resulting CF is: reported ADX LP(a) = ((4.36/card TP)*card LP(a)*2.397)-1.23. Matched venous and ADX specimens that challenged the CF (n=50) had a bias of -1.00 mg/dL (-3.33%) and a linear equation of (y=0.98x -0.25; R=0.994) at the medical decision point of 30.00 mg/dL. Imprecision was 2.4% and 2.4% for BRLC specimens with mean concentrations of 15.04 and 29.40 mg/dL, respectively. Imprecision was 4.2% and 10.5% for ADX patient control specimens with mean venous target concentrations of 66.85 and 14.81 mg/dL, respectively. BRLC had an average bias of -0.31 mg/dL (-2.03%) and 0.41 mg/dL (1.40%) for levels 1 and 2, respectively. ADX patient specimens (n=3) had average biases of -1.47 mg/dL (-3.83%), 1.43 mg/dL (2.15%), and -1.58 mg/dL (-10.64%). ADX LP(a) concentrations from 6.0-80.0 mg/dL were linear (y=1.04x -0.45; R=0.999). The ADX specimen is stable for at least 7 days at RT and at least 5 days under summer and winter shipping conditions. Conclusions All assay parameters met acceptability criteria and were less than the total allowable error of 28.8%. Self-collected capillary ADX specimens are acceptable for the clinical measurement of LP(a), and effectively improve access to testing and identifying high-risk individuals as therapeutic strategies for treatment of elevated LP(a) continue to emerge.

A-143 Comparative Evaluation of K2EDTA Performance in Multinational Vacutainers: A Case Study of “DBO” by Schraubg and “BD” by Becton, Dickinson

Abstract Background This research paper presents a thorough comparison of the anticoagulant properties of K2EDTA in two multinational vacutainer brands, “DBO” by Schraubg and “BD” by Becton, Dickinson, with a specific focus on critical hematological parameters. The study encompassed the analysis of 50 samples, spanning a wide range of values from 60 fl to 110 fl, evaluating key parameters such as Hemoglobin (Hb), Hematocrit (HCT), Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC), and Red Blood Cell (RBC) count. Methods Peripheral blood samples were gathered from 50 outpatient participants using the specified tubes. The samples underwent assessment for six hematological analytes, including RBC Count, hemoglobin, HCT, MCV, MCH, and MCHC. Comparative analysis was performed using the paired t-test. Differences exceeding the total allowable error were considered clinically significant. To assess stability, initial results were compared with those obtained from samples preserved for a duration of 2 hours Results Our findings indicate that the use of “DBO” vacutainers resulted in slightly higher values for Hb, HCT, MCV, MCHC, and RBC count compared to the “BD” vacutainers. Notably, the statistical significance was observed in MCV, HCT, and MCHC across nearly all samples, while Hb and RBC parameters showed no significant changes. Given the crucial role of K2EDTA as an anticoagulant in maintaining the hypotonicity of Red Blood Cells (RBCs), ensuring accurate hematological analyses is imperative. Conclusions Although the T-value for Hemoglobin did not exhibit statistical significance, the study identified notable differences in Hematocrit (HCT) and Mean Corpuscular Volume (MCV). This underscores the importance of selecting the appropriate vacutainer brand to ensure reliability and accuracy in hematological measurements, particularly when assessing MCV, where even slight variations can carry clinical implications. The results underscore the necessity for clinicians and laboratories to carefully consider the choice of vacutainers based on their specific requirements and the critical nature of the hematological parameters under analysis.

B-113 Beckman Coulter DxI 9000 immunoassay analyzer assay performance meets new CLIA 2024 performance goals with highest proportion of Six Sigma performance amongst all major manufacturers

Abstract Background The Clinical Laboratory Improvement Act (CLIA) proficiency testing (PT) criteria will be updated in July 2024 with some goals tightening by up to 40%. It is assumed, but not known, that all assays and instruments will be able to achieve these goals. Using these new CLIA 2024 goals, estimates of current instrument group performance from an international proficiency testing (PT) survey have shown significant differences in quality, calling into question which assays can achieve the new CLIA goals. Currently, the highest performing diagnostic instrument achieves only 35.2% 6-Sigma, while the majority of instruments have less than 15% 6-Sigma performance indicating a higher probability of future PT failures. Methods Eighteen assays that will be governed by new CLIA 2024 goals were assessed for Sigma metric performance on the DxI 9000 immunoassay analyzer: Alpha Fetoprotein (AFP), Beta hCG, Carcinoembryonic antigen (CEA), Cortisol, Creatine Kinase MB (CK-MB), Estradiol, Ferritin, Folate, Follicle-Stimulating Hormone (FSH), Prolactin, Para-thyroid hormone (PTH), Total Prostate specific antigen (Total PSA), Testosterone, Thyroid Stimulating Hormone (TSH), Total Triiodothyronine (TT3),high sensitivity Troponin I, Total Thyroxine (TT4) and Vitamin B12. Precision and bias were determined following CLSI EP5 and EP9 guidelines, measured across 3 reagent lots. CLIA 2024 PT criteria provides the allowable total error for the standard Sigma-metric calculation: Sigma-metric = (TEa - |bias|) / SD Performance of the other major analyzers was assessed using the methodology introduced in 2006 by Westgard JO and Westgard SA. The Sigma-metric predicts future problems with PT and potential optimization of QC procedure opportunities, including fewer Westgard Rules, control levels, even reduced QC frequency and materials leading to less cost and time saved. Results Half (50%) of the assays on DxI 9000 achieves 6-Sigma, outperforming all other major manufacturers in the market who range from only 5% to 35% 6-Sigma. Further, over 78% of the DxI 9000 performance was 4Sigma and higher. Less than 8% of performance fell below 3-Sigma, which was observed at the extreme ends of the reportable range. Conclusions The DxI 9000 assay performance is well designed to meet CLIA 2024’s new PT criteria and has the highest prevalence of 6-sigma assay performance observed on market when compared to the top 5 major instrument manufacturers. Assays with Sigma metrics at 4-Sigma and higher are unlikely to face analytical PT difficulties and can be optimized for reduced Westgard Rules, control levels, and potentially even QC frequency.

B-004 Method Validation of Lactate in the Plasma of Rats

Abstract Background The objective of this study is to validate Lactate (LAC) measurement in rat plasma using the ADVIA 1800 analyzer. Methods LAC was validated in rat plasma using the ADVIA 1800 analyzer. Validation testing included intra-assay and inter-assay precision, accuracy, linearity of dilution, limit of quantitation (LOQ), limit of detection (LOD), reference interval, carry-over, correlation, recovery, and stability. Samples were collected into tubes containing sodium fluoride. Intra-assay precision was determined by analyzing two biological samples and the two quality control levels of Bio-Rad Lyphochek Assayed Chemistry Control 10 consecutive times. Inter-assay precision was determined by analyzing the two quality control levels in duplicate for six days over a 10-day period. Accuracy was calculated using the data obtained from the inter-assay precision testing. For linearity of dilution, Audit MicroControl General Chemistry Linearity Kit and biological samples were diluted and analyzed in duplicate. The LOQ was determined by diluting the calibrator material to produce a value at the low end of the reportable range. Diluted material was tested six times. The LOD was determined by assaying the appropriate blank 10 times. The reference interval was determined by analyzing 21 plasma samples. Correlation between the two ADVIA 1800 analyzers was determined by assaying 10 samples on both analyzers once. The carry-over of the assay was determined by analyzing the high-level quality control material followed by the low-level quality control material. Recovery was determined by analyzing a pair of test samples in duplicate that have been spiked and diluted. The proportional error between the two test samples was calculated. Stability of plasma samples was tested on wet ice, refrigerated, and frozen (at -70°C) for various durations of storage. Results Measurement of LAC in rat plasma met the acceptance criteria for precision, accuracy, linearity of dilution, limit of quantitation, carry-over, recovery, and stability. For intra-assay precision in specimen and control material, the %CV was within ±20%. The inter-assay precision %CV was within ±20%. The total error observed (TEobs) was within ±20% for accuracy and the obtained mean of the control material was within the manufacturer’s acceptable range. For linearity of dilution, the coefficient of determination was ≥ 0.9000, the slope was within 1.00 ± 0.25, and TEobs for each plasma and linearity kit dilution was ≤20%. The LOQ was set at the lowest concentration for which the TEobs was within ±20%. The LOD was calculated by adding the mean concentration obtained and three times the standard deviation. The reference interval was set to the 2.5th to 97.5th percentile interval using Excel software. The carry-over was acceptable at ≤2%. Correlation between the two ADVIA 1800 analyzers was determined to describe any bias in result interpretation. Recovery was acceptable as the proportional error was within ±20%. Stability at all storage conditions was found to be acceptable with a mean %difference within ±20%. Conclusions LAC in rat plasma met the acceptance criteria for all required validation parameters. The ADVIA 1800 analyzer can be used for preclinical studies to test LAC in rat plasma.

A-188 Modal Failure and Effects Analysis, FMEA methodology, as a strategy to increase patient safety

Abstract Background Patient safety during the clinical care process is considered a priority in healthcare. Failure Mode and Effects Analysis (FMEA) is a proactive and systematic method of process evaluation and is used to identifying where and how each phase of the analytical process could fail allowing the detection of the causes and the effects they produce on the quality of the results that are issued. A regular use of this tool makes possible to identify the most critical steps, propose improvement strategies and evaluate their impact. The aim of the study is to evaluate applicability of the FMEA tool to identify errors in the pre analytical, analytical, and post analytical phase of a clinical laboratory as well as the main causes and effects, to reduce them by proposing improvement strategies Methods For each phase into which the laboratory activity is divided, the frequency and type of errors that are made and their final consequences on the patient are evaluated. A risk index (NPR=OxDxS) is calculated for each error considering the frequency with which it occurs (O), the ease with which it is detected (D) and the severity of the consequences on the patient (S). Values goes from 1 (rarely) to 10 (often). Improvement actions are proposed for all errors with a risk index greater than 100 and this index is re-evaluated after the implementation of that improvement measures. This same analysis is performed for three times over the last 10 years (in 2014, 2019 and 2023). Results In FMEA analysis carried out in 2014, a total of 40 errors were identified in the pre-analytical phase (63.5% of the total), 12 in the analytical phase and 11 in the post-analytical phase. 50% of the total errors detected required improvement strategies because they had an NPR≥100 value. In the 2023 evaluation, a total of 27 errors were identified in the pre-analytical phase, 10 in the analytical phase, and 5 in the post-analytical phase but only 6 required improvement strategies, which represents an 80% reduction in the most critical errors for patient safety. However, the pre-analytical phase continues to be the most critical, as it continues to account for 64% of the total errors identified, including the lack of identification of the patient or sample and the inadequate prior preparation of the patient. In analytical and post-analytical phases, the NPR values obtained in 2023 decrease significantly over analysis carried out in 2014 and its not needed to apply improvement strategies. Automation and the IT tools significantly reduce the number of errors with high NPR values, but it is undoubtedly the involvement of service professionals that makes the difference over the years. Conclusions The use of the FMEA methodological tool allows the design of appropriate indicators to detect and reduce errors in the clinical laboratory. Its application as part of a good quality control allows a continuous improvement in the laboratory process and consequently a guarantee of quality for the patient

A-003 Beckman Coulter DxI 9000 Immunoassay Analyzer’s High Sensitivity Troponin I achieves >90% six sigma performance when assessed against clia 2024 performance goals

Abstract Background In July 2024, the Clinical Laboratory Improvement Act (CLIA) proficiency testing (PT) criteria will directly regulate Troponin I performance for the very first time. The new CLIA goal is 0.9 ng/mL or 30%, whichever is greater. CAP previously set a goal of 30% or 3 times the group standard deviation (SD), whichever is greater, a more permissive setting. Estimates of current instrument group performance from an international proficiency testing (PT) survey have shown none of the 5 major diagnostic instruments can achieve the biological minimum goal at a 6-Sigma level, while 4 of the 5 instruments perform at 3 Sigma or below. Performance of these platforms was assessed using the methodology introduced in 2006 by Westgard JO and Westgard SA. The DxI 9000 high sensitivity Troponin I assay was assessed to determine if it could achieve the new CLIA 2024 goals. Methods The DxI 9000 high sensitivity Troponin I assay was assessed with three reagent lots, on both serum and Lithium Heparin (LiHep) samples, following Clinical Laboratory Standards Institute (CLSI) protocols EP05 and EP09 to estimate imprecision and bias. The new CLIA 2024 PT criteria supplied the allowable total error for the standard Sigma-metric calculation: Sigma-metric = (TEa - |bias|) / SD The Sigma-metric predicts not only future problems with PT, but also potential optimization of QC procedures, including fewer Westgard Rules, control levels, even reduced QC frequency which can lead to less cost, time, and materials. Results The majority (91.7%) of data points across the analytical measuring range for DxI 9000’s high sensitivity Troponin I assay from both serum and LiHep samples achieved 6-Sigma performance. For serum, only 8.3% of samples achieved 5-sigma performance. For LiHep, only 4.2% of the performance was 4 Sigma. None of the performance was 3 Sigma or lower. Conclusions The superior precision observed on DxI 9000 high sensitivity Troponin I delivers overwhelming 6-sigma performance when assessed by CLIA’s 2024 goal. This assay is highly unlikely to face PT difficulties and can be optimized for reduced Westgard Rules, reduced control levels leading to a reduction in time, materials, and cost.

A-331 Monitoring Operators Proficiency at Point of Care is Crucial for Reliable Patient Values. A Practical Example with Patient Blood Chloride, Potassium and Sodium Measurands Assayed with i-STAT®

Abstract Background While i-STAT® cartridges offer the Physician a spectrum of analytical methods at the point of care for prompt diagnosis and interventions, these methods have to be harmonized with the laboratory methods in order to reliably detect shifts and trends. With this practical example we illustrate the importance of a program of routine comparisons between the i-STAT® and laboratory methods to detect analytical differences exceeding the CLIA’s criterion and potentially having adverse clinical implications. Methods Patient blood chloride (Cl), potassium (K) and sodium (Na) values as obtained by nurses with i-STAT Chem 8 ™ cartridges (Abbott Laboratories) at the point of care, where daily compared with the values as obtained with the Laboratory method (two cobas 6000®, Roche Diagnostics) using green top BD® lithium heparin tubes (Becton Dickinson) collected within thirty minutes of the i-STAT assay. The data were electronically stored in RALS™ (RALS Informatics) and transferred to Minitab® (Version 21, Minitab Inc.) statistical software. The two analytical methods were compared using the orthogonal and the polynomial ordinary least squares (POLS) regression models and their graphic representations. The aptness of the methods was evaluated with the standardized residuals diagnostics for normality, independence, outliers (Standardized residual >|3|) and influential observations (Hi>0.5). For acceptance of the differences the CLIA’s total error criterion was employed. (CI: target value ± 5%; K: target value ± 0.5 mmol/L; Na: target value ± 4 mmol/L). Results In the first four months of the study the number of differences exceeding the CLIA’s criterion was not acceptable. [Cl: 10% (165/1564); K: 7% (109/1593); Na: 4% (66/1586)]. These differences were occurring throughout the analytical range (AMR). Consequently, the operator’s technique was suspected and the POCT senior technologists (CA, FA) adopted operator specific interventions. This strategy was effective in the following month and the improvements were maintained for seven consecutive months. Monthly differences exceeding the CLIA’s criterion decreased significantly [Cl:1.9% (52/2777): K:0.9% (25/2868): Na:0.5% (15/2896)]. This was clearly illustrated with the dot plot by date and the parallel box plots by month. Regression analysis showed that the orthogonal and the OLS models were equivalent. Cl: Orthogonal y=1.7+0.99x, OLS y=12+0.88x. K; Orthogonal y=0.2+1.2x, OLS y=0.1+0.96x. Na: orthogonal y=3+0.98x, OLS y=14+0.9x. Additionally, the POLS model showed a linear relationship within the AMR intervals with few outliers (Cl=11; K=7; Na=9), no influential observations (Hi<0.5) and equality of monthly regression lines (P>0.05). Conclusions The implementation of daily comparisons between patient values as obtained with the i-STAT method and those as obtained by the Laboratory method in the interval of thirty minutes, allowed the identification of individual operators requiring additional training. This strategy ensured reliable performance for eight consecutive months. This study clearly showed that the addition of continuous supervision and training of operators to quality control and quality assurance practices, ensured the interchangeability of patient values as obtained with i-STAT and those as obtained with the Laboratory method. Electronic collection of data and analysis with appropriate statistical software, such as Minitab, was crucial for the implementation of this program.

B-010 Intercomparison Study of Methods between Atellica Solution® and CI® Analyzers for Sodium, Potassium, and Chloride

Abstract Background Method verification is an essential analysis routinely conducted in accredited Clinical Laboratories whenever a change of method or instrument for a specific analyte is desired. Objectives The aim of the study is to verify that the results measured by the Atellica Solution® analyzer (Siemens) and the new CI® analyzer (Siemens) for Sodium, Potassium, and Chloride are interchangeable. Methods To conduct the intercomparison study of Sodium, Potassium, and Chloride, the techniques were properly calibrated and controlled on both analyzers. For each assay, 40 patient samples were selected, covering the entire measurement range, and analyzed by both instruments. To determine the degree of agreement between the instruments, a Bland Altman analysis of mean differences and a Passing Bablok regression were performed. Statistics are expressed with their 95% confidence intervals (CI). The evaluation of results was carried out using the statistical program Method Validator. Results In both the Bland-Altman and Passing Bablok regression analyses, a slight constant systematic error was detected for all three assays, as the 95% confidence interval of the observed mean difference and the 95% confidence interval of the intercept of the regression line do not include zero. No systematic proportional differences were observed based on the slope, as the 95% confidence interval includes the value one Conclusions The small constant systematic differences found in the analyses should be re-evaluated after performing a new calibration of the methods. In none of the cases are the differences clinically significant, as they do not exceed the total error established in our quality specification. Therefore, it can be concluded that the Atellica Solution® and CI 1900® analyzers are interchangeable for Sodium, Potassium, and Chloride assays

Lithium-ion battery future degradation trajectory early description amid data-driven end-of-life point and knee point co-prediction

This study develops a novel lithium-ion battery future degradation trajectory early description method amid data-driven end-of-life (EOL) point and knee point (KP) co-prediction. Inspired by the concept of KP, the proposed method firstly employs two-stage curve fitting to offline locate KP with minimization total absolute error between the original trajectory and fitted secants as object. Secondly, from partial multi-step fast-charging curves lying in high state-of-charge (SOC) level with only approximately 0.09 SOC interval, our method mines three new aging-dependent features for EOL and knee cycle co-prediction via two optimized Gaussian process regression models. Afterwards, considering the highly linear characteristics of slow degradation stage, knee capacity is further calculated by the linear function fitted via early capacity degradation sequence. Finally, with early capacity degradation sequence, predicted KP and predicted EOL point, the developed method adopts piece-wise cubic Hermite interpolating polynomial to directly generate future degradation trajectory. The verification results using a 140-cell aging dataset demonstrate that the proposed method is powerful for future degradation trajectory early prediction with high accuracy and extremely low real-time computational cost, where most root-mean-square-error and mean-absolute-percentage-error of trajectory prediction results are below 0.03 Ah and 3%, respectively. Our work, for the first time, reveals the possibility of feature extraction from partial multi-step fast-charging curves, and also provides a low-complexity universal framework for accurate future degradation trajectory early prediction.

A framework for comparing large-scale survey assessments: contrasting India’s NAS, United States’ NAEP, and OECD’s PISA

Large-scale survey assessments (LSAs) are important tools for measuring educational outcomes and shaping policy decisions. We present a framework for comparing LSAs to facilitate studying the impact of design choice on the precision of results, contrasting India’s National Achievement Survey (NAS), the United States’ National Assessment of Educational Progress (NAEP), and the OECD’s Programme for International Student Assessment (PISA). Our framework focuses on four key elements: sampling design, assessment design, analysis methodology, and reporting. The notion of total survey error, which is the accumulation of errors across the four key elements, can be used for both designing and evaluating LSAs. As example, we compare statistics that are commonly (but not always) reported from NAS, NAEP, and PISA to summarize outcomes related to sampling, measurement, and reporting. Our examination reveals several key similarities and differences among the three assessments, thereby highlighting the nuanced ways in which each LSA is tailored to meet the specific needs of their purpose and the challenges they face.

Can expected error costs justify testing a hypothesis at multiple alpha levels rather than searching for an elusive optimal alpha?

Simultaneous testing of one hypothesis at multiple alpha levels can be performed within a conventional Neyman-Pearson framework. This is achieved by treating the hypothesis as a family of hypotheses, each member of which explicitly concerns test level as well as effect size. Such testing encourages researchers to think about error rates and strength of evidence in both the statistical design and reporting stages of a study. Here, we show that these multi-alpha level tests can deliver acceptable expected total error costs. We first present formulas for expected error costs from single alpha and multiple alpha level tests, given prior probabilities of effect sizes that have either dichotomous or continuous distributions. Error costs are tied to decisions, with different decisions assumed for each of the potential outcomes in the multi-alpha level case. Expected total costs for tests at single and multiple alpha levels are then compared with optimal costs. This comparison highlights how sensitive optimization is to estimated error costs and to assumptions about prevalence. Testing at multiple default thresholds removes the need to formally identify decisions, or to model costs and prevalence as required in optimization approaches. Although total expected error costs with this approach will not be optimal, our results suggest they may be lower, on average, than when "optimal" test levels are based on mis-specified models.

Associative Learning in Subclinical Hypothyroidism at Different Ranges of Thyroid Stimulating Hormone: A Cambridge Neuropsychological Test Automated Battery (CANTAB) Study of Visual Paired Association Learning Task.

Associative learning deficits are constantly found in subclinical hypothyroidism (SCH). Despite achieving normal thyroid stimulating hormone (TSH) levels, a considerable number of patients undergoing levothyroxine (LT-4) treatment frequently complain about memory retrieval. The Paired Association Learning (PAL) task involves computerised testing on the CANTAB- Cambridge Neuropsychological Test Automated Battery, also considered a screening tool for Alzheimer's disease (AD). This study aimed to investigate the impact of different levels of TSH on visual associative learning in SCH and determine if these impairments were reversed with LT-4. A total of 134 participants were included in this cross-sectional study. Group 1: 35 healthy controls; patients with SCH (Group 2: 33 newly identified cases; Group 3: 32 patients on LT-4 with elevated TSH; Group 4: 34 euthyroid but on LT-4). A thyroid profile and a neuropsychological clinical assessment were done. The visual PAL task was performed on CANTAB. PAL was significantly impaired (p = <0.05) in all 3 patient groups as compared to Group 1. The PAL total errors (adjusted) scores were significantly higher in Groups 2 and 3, indicating that associative learning is definitely impaired in SCH, reaching levels previously seen in patients with AD. Our findings encourage screening for visual associative learning or memory retrieval in patients with SCH. The study present has established a more reasonable threshold of TSH 2.5mIU/L to encourage examination of associative learning and the initiation of LT-4 in SCH. Poor PAL task performance in patients with SCH may have significant implications in clinical settings for suspecting AD.

Grammatical Errors in Students’ Recount Text Writing (A Case Study in The Third Grade of SMAN 22 Jakarta)

This study is aimed to find out grammatical errors and the sources of errors in students’ recount texts. The subject of this study is the third-grade students of SMAN 22 Jakarta in the academic year 2023/2024 which consists of 23 students. Specifically, their recount texts focused on recounting their vacation activities. From the entire third-grade class of 23 students, 16 students were selected as the study sample using the purposive sampling technique. This study used a qualitative approach to analyze and identify grammatical errors. The analysis was carried out by referring to Dulay, Burt &amp; Krashen’s theory, a surface strategy taxonomy consisting of Omission, Addition, Misformation, and Misordering and the sources of errors based on Ellis’s theory are Interlingual Transfer and Intralingual Transfer. The result of this study showed that the total number of grammatical errors made by the students in their recount texts is 32 errors. Which consist of 4 omission errors, 7 addition errors, 8 misordering erros, and 13 misinformation errors. Accordingly, the most frequent error is misinformation error which corresponds to 13 (40,6%) of the total error. Furthermore, this study also revealed that most of the errors are caused by Intralingual Transfer (30 errors or 94% of the total error). Based on these findings, it concluded that the students had some difficulties in applying English grammar rules in their writings. Therefore, it is suggested to be aware and pay more attention to improve the English teaching and learning process.

Corneal Epithelial Wavefront Error as a Novel Diagnostic Marker for Epithelial Basement Membrane Dystrophy.

Synopsis: Corneal epithelial wavefront error and epithelial thickness variance qualify as highly sensitive and specific biomarkers for epithelial basement membrane dystrophy (EBMD). The biomarkers show a normalization after treatment of EBMD with phototherapeutic keratectomy. Purpose: To gauge the diagnostic value of epithelial basement membrane dystrophy (EBMD), a novel spectral-domain optical coherence tomography (SD-OCT)-based imaging modality for simultaneous morphological (thickness profile) and refractive (optical wavefront) assessment of the corneal epithelial layer in one of the most common but often underdiagnosed corneal dystrophies. Methods: In this prospective observational study, a total of 32 eyes of 32 patients diagnosed with EBMD and 32 eyes of 32 healthy control subjects were examined with high-resolution anterior segment SD-OCT (MS-39; CSO, Florence, Italy). Various epithelial thickness and epithelial wavefront-derived terms were compared between groups and receiver operating characteristic (ROC) curves were computed to analyze the diagnostic capacity of the respective parameters. A total of 17 of 32 EBMD patients underwent treatment with phototherapeutic keratectomy (PTK) and were followed up for 3 months. Results: Epithelial thickness variance (60.4 ± 56.7 µm versus 7.6 ± 6.1 µm) and interquartile range (11.0 ± 6.9 versus 3.3 ± 1.9 µm) were markedly elevated in EBMD patients as compared with healthy controls (both with p < 0.001). Epithelial wavefront analysis showed a highly statistically significant excess in all examined aberration terms in EBMD patients (all with p < 0.001). Significantly greater areas under the curve (AUCs) were yielded by the epithelial wavefront-derived parameters (e.g., total epithelial wavefront error: AUC = 0.966; 95% confidence interval (CI) 0.932-1) than by the epithelial thickness-derived parameters (e.g., variance: AUC = 0.919; 95% CI 0.848-0.990). Conclusions: Corneal epithelial wavefront aberrometry proved valuable as an objective biomarker for EBMD, with high sensitivity and specificity. PTK resulted in a reduction of morphological and refractive epithelial irregularities in EBMD.

Efficient spectrum allocation by heterogeneous automated frequency coordination network within 6 GHz band

This work proposes a heterogeneous automated frequency coordination network (HAFCN) to enhance reliability and enable dynamic spectrum allocation for unlicensed Wi-Fi devices (UWDs) within the 6 GHz band. This process relies heavily on spectrum sensing within the HAFCN. However, the widespread implementation of spectrum sensing by multiple UWDs in an automated frequency coordination (AFC) network using conventional fusion schemes poses computational challenges at the AFC provider. In response to this challenge, we present a selective soft-information (SSI) fusion scheme for the proposed HAFCN. First, we present generic mathematical expressions of false-alarm and missed detection probabilities for the HAFCN using an SSI fusion scheme. Second, a generalized AFC SSI fusion problem (GASFP) is formulated to minimize the system’s total error probability. Further, to mitigate the AFC provider’s overhead in solving the GASFP, this work presents the swift-sensing problem, determining the minimum antennas at UWD required to achieve a desired total error probability. Finally, comparative numerical results demonstrate that the HAFCN with the SSI fusion scheme shows a significant performance improvement over conventional fusion schemes in terms of the total error probability.

Full-Body Harness versus Waist Belt: An Examination of Force Production and Pain during an Isoinertial Device Maximal Voluntary Isometric Contraction.

This study examined the differences in participant force production and pain between a squat maximal voluntary isometric contraction (IMVIC) performed with either a waist belt (WB) or full-body harness (FBH) on the Desmotec D.EVO isoinertial device (D.EVO). Agreement between FBH IMVIC and a traditional force plate squat MVIC (TMVIC) was also assessed. Twenty adults completed FBH, WB, and TMVIC assessments on two separate occasions. Two-way treatment x time ANOVAs were conducted to compare force outputs and pain between treatments (FBH vs. WB) across time. Test-retest reliability was assessed using intraclass correlation coefficients. Associations between outcomes were determined using Pearson's r. Standard error of estimate, constant error, total error, and Bland-Altman plots were used to assess agreement between IMVIC and TMVIC. FBH and WB IMVIC exhibited good to excellent reliability (ICC2,1 = 0.889-0.994) and strong associations (r = 0.813 and 0.821, respectively) when compared to TMVIC. However, agreement between FBH and TMVIC was poor. No significant interaction or main effects were observed for pain. FBH maximum isometric force (MIF) was significantly higher than WB MIF. WB IMVIC was the only significant predictor of TMVIC (R2 = 0.674). Our findings indicate that the D.EVO should not be utilized as a replacement for a traditional MVIC setup.

Finite Element Modelling for the Dynamic Behaviour Analysis of a Structure with Hi-Lok Fasteners

The number of Hi-Lok fasteners used in the assembly of aircraft structures is very high. For this reason, an efficient modelling technique is required to accurately analyse the dynamic behaviour of the structures. In this study, a modelling technique with special emphasis on Hi-Lok modelling is proposed to analyse the dynamic behaviour of a test structure with Hi-Lok fasteners. Four different finite element (FE) models to represent the test structure with the Hi-Lok fasteners were developed using MSC Software packages. The natural frequencies and mode shapes obtained from the FE models are compared with those of the Experimental Modal Analysis (EMA) in terms of total error, computational time and memory disk usage. It was found that the model D with the simplified beams representing Hi-Lok predicts the dynamic behaviour of the test structure with an accuracy of 96.6% and with comparatively low computational time and memory disk usage. This proposed modelling scheme may provide useful approaches to aircraft researchers and engineers for the dynamic analysis of the structures.

Surface enhanced transmission Raman spectroscopy: Quantitative performances for impurity analysis in complex matrices

A transmission detection mode was investigated with SERS analyses (SETRS). A comparison between backscattering and transmission detection modes was conducted to demonstrate the feasibility of performing SETRS analyses. The impact of various parameters on the SERS signal intensity such as sample volume, lens collection optic, laser beam size and laser power were then examined. The analytical performances of SETRS were further evaluated through the quantification of an impurity (4-aminophenol) ranging from 3 to 20 µg/mL in a commercial pharmaceutical product using a total error risk-based approach. To account for expected variability of routine analysis, 9 batches of silver nanoparticles suspensions were used and experiments were performed over 5 different days and by 2 operators. Univariate spectral analysis based on a quadratic regression was compared to a multivariate approach using a partial least square regression. The presented results demonstrated that SETRS can be used to determine an impurity in a complex matrix opening new perspectives for quantitative applications.

Waste not want not: the story of surgical trash.

Our escalating reliance on disposable products in the operating room has generated a large amount of waste, cost, and environmental pollution. Heath damages from the pollution caused by the US healthcare industry cause as much harm, as measured by disability-adjusted life years, as total medical errors. Our response to our own environmental impact should be proportional to that harm. Understanding the waste streams we create and the factors that contribute to our large waste generation in the operating room can help us target solutions to our most harmful practices. Recent studies within the field of medical waste in ObGyn have included a systematic review analyzing most effective practices for waste reduction and environmental life cycle analyses of specific medical procedures. Operating room waste includes regulated medical waste, pathologic waste/chemotherapy, sharps, general municipal waste, recycling, linens, and anesthetic gases. The most effective way to reduce the environmental impact from medical waste is to reduce our use of disposable supplies in favor of durable reusable materials. Other important interventions include eliminating 'overage' of unused supplies, optimizing use of anesthetic gas, custom pack scale backs, and proper waste segregation. This review of operative waste is intended to aid healthcare facilities in understanding and addressing their own environmental impact.

Utilization of Western Aphasia Battery–Revised Spoken Language Subtest Stimuli to Characterize Differentially Diagnostic Characteristics of Acquired Apraxia of Speech

Purpose: There is a need for stimuli that can be used in the assessment of apraxia of speech (AOS) characteristics. AOS often presents with aphasia, and the Western Aphasia Battery–Revised (WAB-R) is administered extensively in clinical practice for the assessment of aphasia. This preliminary study investigated error production of differentially diagnostic characteristics of AOS (phonetic and prosodic errors) in response to existing spoken language subtest stimuli of the WAB-R in individuals with concomitant AOS and aphasia and aphasia only. Method: Ten participants presenting with aphasia and potential motor speech impairment were included. Presence of AOS was determined for five individuals. Speech production errors were analyzed using narrow transcription methods in response to the Naming, Repetition, and Spontaneous Speech subtests of the WAB-R for both AOS and aphasia and aphasia-only groups. Results: Differences in total error production for both phonetic and prosodic errors were reported between the AOS and aphasia and aphasia-only groups. In addition, the phonetic complexity of the stimuli correlated to the phonetic and prosodic error production in both groups. An effect of WAB-R subtest was not reported for either group. Conclusion: The diversity of elicited spoken language production across multiple contexts makes the use of the spoken language subtest stimuli a feasible component of a comprehensive AOS assessment, since AOS is often concomitant with aphasia.