Positive Threshold Research Articles

Role of measurable residual disease quantified by 4 to 6 color flow cytometry before allogeneic hematopoietic stem cell transplantation for high-risk Philadelphia-negative acute lymphoblastic leukemia

Background: Measurable residual disease (MRD) status before allogeneic hematopoietic stem cell transplantation (AHSCT) is commonly associated with a high risk of relapse. It is still uncertain whether AHSCT could overcome the negative impact of MRD positivity (MRD+), especially in patients with high-risk Philadelphia negative acute lymphoblastic leukemia (Ph-negative ALL). Materials and methods: An observational retrospective study was conducted on patients with high-risk Ph-negative ALL who underwent AHSCT between January 2005 and June 2022. The patients selected were in complete remission (CR): with 80% in CR1 (n = 69) and 20% in CR2 (n = 17). Graft sources were bone marrow (BM) in 71% of patients and peripheral blood stem cells in 29% of patients. The conditioning regimen was TBI or chemotherapy-based (CT). Bone marrow MRD level was quantified using 4-6 color multiparametric flow cytometry (MFC). The threshold for MRD positivity was ≥ 0.1%. Results: The study included 86 patients (45 B-ALL and 41 T-ALL) with a median age of 18 years (range, 4–55 years). The median level of MRD pre-AHSCT (pre-MRD) was 0.4×10-3 (range, 0.01-75.6×10-3). After a median follow-up of 25 months (range 1-205 months), the cumulative incidence of relapse (CIR) was significantly higher in the MRD+ group (39% vs. 20%, p = 0.04). The median time of relapse post-AHSCT was 14 months (range, 1-203 months) in the MRD+ group and 32 months (range, 4-209 months) in the MRD- group (p = 0.28). Non-relapse mortality (NRM) was 15% in both groups (p = 0.97). The 2-year estimated overall survival (OS) and event-free survival (EFS) were 61% vs. 74% (p = 0.07) and 58% vs. 70% (p = 0.10) in the MRD+ and MRD- groups, respectively. A subgroup analysis in MRD+ patients showed that a TBI-based conditioning regimen was distinctly associated with lower CIR (22% vs. 60% respectively, p = 0.04), improved OS (82% vs. 36% respectively, p = 0.007) and better EFS (73% vs. 38%, p = 0.04) compared to CT-based. In a multivariate analysis, pre-AHSCT MRD+ status and non-TBI-based conditioning were significantly associated with inferior OS (OR, 2.30; 95% CI, [1.027-5.168], p = 0.04 and OR, 3.91; 95% CI, [1.624-9.418], p = 0.002, respectively). The only predicting factor of lower EFS was the non-TBI-based regimen (OR, 2.82; 95% CI, [1.308-6.097], p = 0.008). Non-TBI-based and CR2 were significantly associated with higher CIR (OR, 6.25; 95% CI, [1.947-20.055], p = 0.002 and OR, 4.74; 95% CI, [1.197-18.791], p = 0.03, respectively). Peripheral stem cell source was significantly associated with higher NRM (OR, 6.55; 95% CI, [1.488-28.820], p = 0.01). Conclusion: High-risk Ph-negative ALL patients with MRD ≥ 10-3 prior AHSCT had lower OS compared to MRD- patients and may benefit from TBI as a conditioning regimen before AHSCT.

RAGE and its ligand amyloid beta promote retinal ganglion cell loss following ischemia-reperfusion injury.

Glaucoma is a progressive neurodegenerative disease associated with age. Accumulation of amyloid-beta (Aß) proteins in the ganglion cell layer (GCL) and subsequent retinal ganglion cell (RGC) loss is an established pathological hallmark of the disease. The mechanism through which Aß provokes RGC loss remains unclear. The receptor for the advanced glycation end product (RAGE), and its ligand Aß, have been shown to mediate neuronal loss via internalizing Aß within the neurons. In this study, we investigated whether the RAGE-Aß axis plays a role in RGC loss in experimental glaucoma. Retinal ischemia was induced by an acute elevation of intraocular pressure in RAGE-/- and wild-type (WT) control mice. In a subset of animals, oligomeric Aß was injected directly into the vitreous of both strains. RGC loss was assessed using histology and biochemical assays. Baseline and terminal positive scotopic threshold (pSTR) were also recorded. Retinal ischemia resulted in 1.9-fold higher RGC loss in WT mice compared to RAGE-/- mice (36 ± 3% p < 0.0001 vs. 19 ± 2%, p = 0.004). Intravitreal injection of oligomeric Aß resulted in 2.3-fold greater RGC loss in WT mice compared to RAGE-/- mice, 7-days post-injection (55 ± 4% p = 0.008 vs. 24 ± 2%, p = 0.02). We also found a significant decline in the positive scotopic threshold response (pSTR) amplitude of WT mice compared to RAGE-/- (36 ± 3% vs. 16 ± 6%). RAGE-/- mice are protected against RGC loss following retinal ischemia. Intravitreal injection of oligomeric Aß accelerated RGC loss in WT mice but not RAGE-/-. A co-localization of RAGE and Aß, suggests that RAGE-Aß binding may contribute to RGC loss.

High-Performance Indium-Based Oxide Transistors with Multiple Channels Through Nanolaminate Structure Fabricated by Plasma-Enhanced Atomic Layer Deposition

An atomic-layer-deposited oxide nanolaminate (NL) structure with 3 dyads where a single dyad consists of a 2-nm-thick confinement layer (CL) (In0.84Ga0.16O or In0.75Zn0.25O), and a barrier layer (BL) (Ga2O3) was designed to obtain superior electrical performance in thin-film transistors (TFTs). Within the oxide NL structure, multiple-channel formation was demonstrated by a pile-up of free charge carriers near CL/BL heterointerfaces in the form of the so-called quasi-two-dimensional electron gas (q2DEG), which leads to an outstanding carrier mobility (μFE) with band-like transport, steep gate swing (SS), and positive threshold voltage (VTH) behavior. Furthermore, reduced trap densities in oxide NL compared to those of conventional oxide single-layer TFTs ensures excellent stabilities. The optimized device with the In0.75Zn0.25O/Ga2O3 NL TFT showed remarkable electrical performance: μFE of 77.1 ± 0.67 cm2/(V s), VTH of 0.70 ± 0.25 V, SS of 100 ± 10 mV/dec, and ION/OFF of 8.9 × 109 with a low operation voltage range of ≤2 V and excellent stabilities (ΔVTH of +0.27, -0.55, and +0.04 V for PBTS, NBIS, and CCS, respectively). Based on in-depth analyses, the enhanced electrical performance is attributed to the presence of q2DEG formed at carefully engineered CL/BL heterointerfaces. Technological computer-aided design (TCAD) simulation was performed theoretically to confirm the formation of multiple channels in an oxide NL structure where the formation of a q2DEG was verified in the vicinity of CL/BL heterointerfaces. These results clearly demonstrate that introducing a heterojunction or NL structure concept into this atomic layer deposition (ALD)-derived oxide semiconductor system is a very effective strategy to boost the carrier-transporting properties and improve the photobias stability in the resulting TFTs.

Abstract 2183: Absolute quantification of PD-L1 gene expression in single cell on tissue for accurately predicting response to ICIs

Abstract Background PD-L1 immunohistochemistry (IHC) has been traditionally used for predicting clinical responses to immune checkpoint inhibitors (ICIs). However, there are at least 4 different assays and antibodies used for PD-L1 IHC, each developed with a different ICI. Spatial transcriptomic analysis at the single cell level can be helpful for deeply characterize the complexity and heterogeneity of tumors. We set to test if in-situ hybridization-based RNA scope coupled to single cell quantification is a robust method to determine PD-L1 mRNA expression levels in each cell and furthermore efficacy of predicting response to ICIs as compared to routinely used standardized IHC procedures. Method FFPE sections from retrospectively collected surgically resected NSCLCs (adenocarcinoma and squamous cell carcinoma) tumor with progression disease or complete response from adjuvant pembrolizumab therapy were used. Target genes CD274 (PD-L1) and GZMB (Granzyme B) were assessed. For fluorescent detection, the label probe was conjugated to Opal 570 and 620 respectively. Tissues cells were counterstained with DAPI to detect the nuclei. A Digital pathology software QuPath was used for cell segmentation and dot’s detection for gene expression quantification and further classification. Results Difference in expression levels were seen between PD-L1 and GZMB across the tumor with PD-L1 staining mostly located in the tumoral area and Granzyme B in stromal area of the NSCLC tissue. This is consistent with the expected expression of PD-L1 on tumor epithelial cells and Granzyme B on T cells. This heterogeneity in the signal distribution specific to the analyzed tissue correspond to intra-tissue cells metabolism heterogeneity between cell types. This heterogeneity of expression was captured though a digital workflow capable of quantifying the number of cells expressing PD-L1 and GZMB. Among the cells expressing the markers, 96% were positive for PD-L1 for the tumor that did not respond to therapy with the threshold of positivity being set at 1 of dots, that corresponds to 1 transcript, per cell. Conclusion Our results demonstrate that PD-L1 was highly expressed in a tumor context that was not responding to PD-1 ICI inhibitor. Measurement of mRNA expression at the single cell level on tissue provides another layer of PD-L1 detection which can be exploited to predict tumor response to ICI suggesting that moving forward with this technology is a viable approach for this dynamic biomarker. Citation Format: Amandine Gerstenberg, Adele Ponzoni, Corinne Ramos, Jonathan Stauber. Absolute quantification of PD-L1 gene expression in single cell on tissue for accurately predicting response to ICIs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2183.

Abstract 5388: A unified computational pathology method to quantify HER2 expression from raw IHC and IF images in breast cancer

Abstract Background: The development of automated quantitative methods to measure biomarker expression such as HER2 aims at reducing the subjective variability of pathologist-performed biomarker assessment of immunohistochemically (IHC) stained tissue slides. As an example, the deep learning-based Quantitative Continuous Scoring (QCS) algorithm [1] enables the objective measurement of biomarker expression based on the detection of individual tumor cells in the tumor regions and - for each cell, on the instance segmentation of its nucleus, cytoplasm, and membrane compartments. Methods: In order to extend the QCS image analysis to similarly analyze tissue slides stained with immunofluorescence (IF), we re-trained the fully supervised deep-learning models, adjusted the normalization of images on tissue controls to account for variability between different staining batches, and finally used the normalized signal in IF instead of the Optical Density (OD) signal in IHC as a 8-bit grayscale image on which the biomarker expression is estimated. We performed QCS on HER2 IF images (HER2 clone 29D8 [CST], imaged with Vectra [Akoya] in parallel with HER2 IHC clone 4B5 [Roche Tissue Diagnostics]) performed on 26 primary and metastatic breast cancer samples representing the full range of HER2 expression, from null to highly overexpressed. Results: Our analysis demonstrated that the QCS-based scoring on IHC-HER2 images correlates with the QCS-based scoring on IF-HER2 images. We observed a Pearson correlation of R=0.92 between the median membrane OD in IHC and the median normalized membrane signal in IF. Defining a positive cell as having an estimated membrane expression higher than a given so-called positivity threshold, we found a median Pearson correlation of R=0.85 between the percentage of positive cells detected in IHC and the percentage of positive cells detected in IF for increasing values of positivity thresholds. Correlation of the QCS median normalized membrane signal in IF was R=0.91 with mRNA (ERBB2 transcript levels [Nano String]) and R=0.88 with IHC-based H-scores, against R=0.83 and R=0.87 respectively for the QCS median membrane OD signal in IHC. Conclusion: We describe the extension of a computational pathology-based approach for biomarker quantification in IHC to IF stained tissue slides. The consistency of the image analysis method translates into the consistency of the measurements in the two imaging methods. The use of IF could enable the improved quantification of expression, co-localization and spatial distribution of multiple proteins on the tissue sample.

Abstract 4625: A comprehensive guided workflow for highplex imaging, tissue segmentation, and multiplex cellular phenotyping for tumor microenvironment analysis

Abstract The growth in cancer immunotherapy agents requires an understanding of the immune contexture of the tumor microenvironment (TME). Understanding immune contexture requires multiplex staining, imaging, and analysis to obtain multi-marker phenotypes of specific cells and analyze their biodistribution in the TME. Imaging Mass Cytometry™ (IMC) is the method of choice for single-step staining and highplex imaging of FFPE tissues. FFPE tissue is autofluorescent, which limits the utility of immunofluorescence methods. Lung and colorectal tissue (and bone, skin, etc) are highly autofluorescent, and therefore good targets for IMC. However, developments in analysis software for highplex imagery have not kept pace with imaging advances. We present a comprehensive workflow designed specifically for highplex image analysis, covering tissue segmentation, cell segmentation based on IMC DNA images, cellular phenotyping, and spatial analyses. Lung and colorectal tissue sections with a 30-marker IMC panel of structural, tumor, stroma, immune cell, and immune activation markers were imaged (Hyperion+™, Standard BioTools). Highplex image analysis (Phenoplex™, Visiopharm) was performed as a multi-step workflow in a single software package that includes: conversion of IMC images to pyramidal format; easy visualization methods for displaying different marker subsets; a paint-to-train algorithm for tissue segmentation (into tumor, stroma, blood vessels, etc.); deep-learning-based nuclear segmentation pre-trained on IMC DNA channels; cellular phenotyping based on thresholds based on visual assessment of positivity; spatial biodistribution metrics for cell populations; and a flexible set of outputs for downstream analysis. Tissue segmentation was used to divide the tissue into tumor, stromal, and tumor margin regions, and these regions were used to compare the immune contexture through a series of t-SNE images partitioned by spatial region. We demonstrate that a simple analysis workflow can be used for highplex images of different tissue types by users with no programming knowledge. Visualization templates for the marker subsets and the pre-trained IMC nuclear segmentation are reusable. A new tissue segmentation algorithm for each tissue type is required, as are new thresholds for biomarker positivity. Spatial biodistribution metrics, heatmaps and partitioned t-SNE plots were generated for each tissue type with a minimum of work. Highplex IMC imaging of lung and colorectal tumor samples is a simple and effective means of obtaining high-parameter images without interfering autofluorescence. Having a comprehensive workflow for the analysis of this complex data makes obtaining useful results from highplex images more accessible to biologists and immunologists by circumventing the requirement for expert programming for each specific application. Citation Format: Brenna O'Neill, Smriti Kala, Sam Lim, Clinton Hupple, Nina Lane, Rasmus Norre Sorensen, Rasmus A. Lyngby, Alessandro Massaro, Andreas Hussing, Jeppe Thagaard, Johan Dore-Hansen, James Robert Mansfield. A comprehensive guided workflow for highplex imaging, tissue segmentation, and multiplex cellular phenotyping for tumor microenvironment analysis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4625.

Abstract 2300: Non-invasive liquid biopsy assay for the detection of ASCL1 expression in CTCs of patients with lung cancer

Abstract Background: Lung cancer (LC) is the deadliest cancer worldwide, with small cell LC (SCLC) and neuroendocrine (NE) LC being the most aggressive and lethal forms. The transcription factor, achaete-scute homolog 1 (ASCL1), regulates neuronal and NE cell development, and is a hallmark of the ASCL1(+) SCLC subtype. Further, investigating subtype has become increasingly important as new drug candidates emerge for SCLC that may be efficacious in only some patients. ASCL1 by IHC tissue biopsy is highly specific, detecting patients who have transformed from NSCLC to SCLC and have acquired resistance to EGFR tyrosine kinase inhibitor therapy in NSCLC. Quantification of ASCL1 on circulating tumor cells (CTCs) is a blood-based, non-invasive alternative to tissue biopsy that provides functional protein-level expression data to monitor lung cancer patients across the disease continuum, informing patient treatment. Methods: A 4-color immunofluorescence (IF) assay was developed to detect ASCL1 expression in CTCs from routine blood samples, comprising detection of nucleated cells (DAPI), cytokeratin positive CTCs, CD45(+) white blood cells (WBC), and ASCL1(+) cells. During validation, cancer cell lines (SHP-77 [ASCL(+)] and U2-OS [ASCL1(-)]) were spiked into normal blood at a ratio of 1:10,000 (CLC/WBC) and plated onto coated glass slides. Slides were stained, imaged, and CTC candidates were identified with a proprietary imaging algorithm. The threshold of ASCL1 positivity (316 MFI) included 99% of all ASCL1(-), U2-OS cells. Assay specificity, sensitivity, overall accuracy, and subcellular localization of biomarker expression were assessed. The ability of the assay to quantify ASCL1 expression in CTCs was confirmed using 31 samples from 11 Extensive Stage SCLC patients. Results: The ASCL1 CTC assay achieved an overall accuracy of 0.992 (95% CI 0.081, 0.993), and an analytical specificity and sensitivity of 0.990 and 0.995, respectively. The assay displayed a positive predictive value and a negative predictive value of 0.979 and 0.998, respectively, determined by evaluating ASCL1 expression in SHP-77 (N=4062) and U2-OS (N=8645). ASCL1 expression was detected in the nucleus of all SHP-77 and majority of SCLC patient CTCs. Of the 11 Extensive Stage SCLC patients tested, 9 (82%) showed at least one conventional CTC (0.02 - 9.63 CTCs/mL), and all 9 (100%) had at least 1 ASCL1(+) CTC (0.06 - 5.5 CTCs/mL). Conclusion: This blood based ASCL1 assay is a highly specific and sensitive approach to monitor ASCL1 expression on CTCs isolated from the blood of lung cancer patients. Citation Format: Luisa Fernandez, Andrew Kunihiro, Mark Frilles, Alisa Tubbs, Jason Christiansen, David Bourdon. Non-invasive liquid biopsy assay for the detection of ASCL1 expression in CTCs of patients with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2300.

Abstract 6603: BRCA1 promoter methylation in sporadic breast cancer patients detected by liquid biopsy

Abstract Background: BRCA1 promoter methylation (PM) is an early initiating event in cancer, occurring in 3 to 65.2% of all breast tumors, and 30 to 65% of triple negative tumors. BRCA1 PM has been associated with defective homologous recombination repair (HRR), early onset of breast and ovarian cancer, and improved clinical response to adjuvant chemotherapy. Historically, there has been no diagnostic assay that comprehensively evaluates both BRCA1 PM and genomic alterations in cell-free circulating tumor DNA (ctDNA). Here, we describe the novel detection of BRCA1 PM and genomic alterations in a cohort of patients with breast cancer using GuardantINFINITY, a liquid biopsy assay interrogating 800+ genes and genome-wide methylation detection. Method: We assessed for BRCA1 PM in ctDNA from 274 patients with late-stage breast cancer. Genomic sequencing of 800+ genes and PM profiling of 398 genes was performed by GuardantINFINITY. The positive calling threshold for PM was established by comparing cell-free DNA derived from patients with cancer and cancer-free donors. The limit of detection (LoD) was determined through in silico and experimental titrations of ctDNA from clinical samples and cell lines with known gene PM into the plasma of cancer-free donors. Results: Among the 274 patients with advanced breast cancer, 8 (2.9%) had germline pathogenic mutations in BRCA1, BRCA2, or ATM. BRCA1 PM was detected in 11/274 (4.0%) patients at the predefined threshold of &amp;gt;99% specificity. BRCA1 PM detection in this cohort was 8.9% (8/90) when excluding samples with low tumor shedding (&amp;lt;1% epigenomic tumor fraction in cfDNA). Among the 11 patients with BRCA1 PM detected in ctDNA, one had a co-occurring somatic BRCA1 nonsense variant (p.S361*); none of the remaining patients with BRCA1 PM had another HRR-related mutation detected in cfDNA. Among patients without BRCA1 PM detected, pathogenic somatic alterations were detected in BRCA2, ATM, and CHEK2 in 25 (9.4%) patients. In silico simulations using clinical samples with BRCA1 PM indicated an LoD of 0.0408%. BRCA1 PM was not detected in 3210 individual and mixed cancer-free clinical samples, indicating a high specificity for BRCA1 PM calls. Conclusion: GuardantINFINITY, a plasma-based diagnostic assay, detected both BRCA1 PM and genomic alterations in this unspecified advanced breast cancer cohort. The BRCA1 PM detection rates of 4.0-8.9% are consistent with values previously reported in the literature. As BRCA1 PM has important prognostic and therapeutic implications for the management of breast (as well as ovarian) cancers, additional studies are warranted to further describe the PM patterns across breast cancer subtypes and how these patterns both influence and are influenced by disease evolution and therapeutic response. Liquid biopsy thus serves as a suitable method to noninvasively identify and monitor changes in both genomics and epigenomics. Citation Format: Jennifer Yen, Sai Chen, Colby Jenkins, Brooke Overstreet, Yu Fu, Jun Zhao, Tingting Jiang, Leylah Drusbosky, Stephen Pettitt, Michael Dorschner, Lauren Lawrence, Han-Yu Chuang, Andrew Tutt. BRCA1 promoter methylation in sporadic breast cancer patients detected by liquid biopsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6603.

Evaluation of a new complement-dependent lymphocytotoxicity cross match method using an automated cell counter, the NucleoCounter® NC-3000™.

Complement-dependent lymphocytotoxicity cross match (CDC-XM) is the ultimate test of donor/recipient compatibility prior to organ transplantation. This test is based on cell viability, evaluated under fluorescence microscopy by an operator after proper staining. The determination of the positivity threshold may vary depending on the operator. We developed a new method in which the final step of determining cell viability is automated using the NC-3000™ (Chemometec®), an image cytometer able to precisely determine the percentage of dead/live cells in a suspension. After T and B donor cells isolation by negative selection, complement-dependent lysis was performed in macrovolumes in a PCR plate. Then, cell viability was measured by the NC-3000™. The sensitivity and routine CDC-XM results of this new method were compared to those of CDC-XM reference method using Terasaki plates. The sensitivity of CDC-XM expressed in the ASHI scoring system of this method was similar to the reference method results for a dilution range of the positive controls. Similarly, the results of the new method were comparable in a clinical situation to those obtained with the reference method after a study of 10 cross-matches, of which 5 cross-matches with DSA were positive and five cross-matches without DSA were negative. Moreover, ASHI scores were similar to those obtained using the reference method, and the mortality percentage was reproducible (CV < 15%). The assessment of cell viability by the NC-3000™ is easy to perform and highly reproducible but requires CDC-XM to be performed by the macrovolume method. The determination of a precise percentage of viability/mortality by the automation excludes operator variability and allows a better understanding of results close to the decision threshold.

Prevalence of Antiphospholipid Antibodies and Association With Incident Cardiovascular Events

The prevalence of antiphospholipid antibodies (aPL) and their association with future atherosclerotic cardiovascular disease (ASCVD) risk has yet to be thoroughly investigated. To determine the association between measurements of aPL at a single time point and ASCVD risk in a diverse population. This cohort study measured 8 aPL (anticardiolipin [aCL] IgG/IgM/IgA, anti-beta-2 glycoprotein I [aβ2GPI] IgG/IgM/IgA, and antiphosphatidylserine/prothrombin [aPS/PT] IgG/IgM) by solid-phase assays in plasma from participants of the Dallas Heart Study (DHS) phase 2, a multiethnic, population-based cohort study. Blood samples were collected between 2007 and 2009. The median follow-up was 8 years. Statistical analysis was performed from April 2022 to January 2023. Associations of aPL with future ASCVD events (defined as first nonfatal myocardial infarction, first nonfatal stroke, coronary revascularization, or death from cardiovascular cause) were assessed by Cox proportional hazards models, adjusting for known risk factors, medications, and multiple comparisons. Among the 2427 participants (mean [SD] age, 50.6 [10.3] years; 1399 [57.6%] female; 1244 [51.3%] Black, 339 [14.0%] Hispanic, and 796 [32.8%] White), the prevalence of any positive aPL tested at a single time point was 14.5% (353 of 2427), with approximately one-third of those detected at a moderate or high titer; aCL IgM had the highest prevalence (156 individuals [6.4%]), followed by aPS/PT IgM (88 [3.4%]), aβ2GPI IgM (63 [2.6%]), and aβ2GPI IgA (62 [2.5%]). The IgA of aCL (adjusted hazard ratio [HR], 4.92; 95% CI, 1.52-15.98) and aβ2GPI (HR, 2.91; 95% CI, 1.32-6.41) were independently associated with future ASCVD events. The risk further increased when applying a positivity threshold of at least 40 units (aCL IgA: HR, 9.01 [95% CI, 2.73-29.72]; aβ2GPI IgA: HR, 4.09 [95% CI, 1.45-11.54]). Levels of aβ2GPI IgA negatively correlated with cholesterol efflux capacity (r = -0.055; P = .009) and positively correlated with circulating oxidized LDL (r = 0.055; P = .007). aβ2GPI IgA-positive plasma was associated with an activated endothelial cell phenotype as evidenced by increased surface expression of surface E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1. In this population-based cohort study, aPL detectable by solid-phase assays were present in a substantial proportion of adults; positive aCL IgA and aβ2GPI IgA at a single time point were independently associated with future ASCVD events. Longitudinal studies with serial aPL measurements are needed to further explore these findings.

P‐1.5: The effects of the temperature of fluorination treatment on the reliability of an indium‐gallium‐zinc oxide thin‐film transistor

This work reported the effects of the temperature of fluorination by fluorine plasma treatment on the performance, reliability, and stability of an indium‐gallium‐zinc oxide thin‐film transistor. While fluorination leads to a more positive threshold voltage, improved reliability against electrical stress and improved stability against non‐oxidizing heat‐treatment, that performed at a higher temperature is found to be more effective.

True Nonvolatile High-Speed DRAM Cells Using Tailored Ultrathin IGZO.

Severe power consumption in the continuous scaling of Silicon-based dynamic random access memory (DRAM) technology quests for a transistor technology with a much lower off-state leakage current. Wide bandgap amorphous oxide semiconductors, especially indium-gallium-zinc-oxide (IGZO)exhibit many orders of magnitude lower off-state leakage. However, they are typically heavily n-doped and require negative gate voltage to turn off, which prevents them from true nonvolatile operation. The efforts on doping density reduction typically result in mobility degradation and high Schottky barriers at contacts, causing severe degradation of on-current and operation speed of the DRAM cells. Here, high-speed true nonvolatile DRAM cells are successfully demonstrated by deep suppression of doping density in the IGZO channel using in situ oxygen ion beam treatment and ohmic contact engineering by inserting a thin In-rich indium-tin-oxide (ITO) at contact regions. A record high on-current of 40µA µm-1 at a large positive threshold voltage of 1.78V enables the first true nonvolatile DRAM with the fastest write speed of 10ns and data retention up to 25 h under power interruption, five orders of magnitude higher than the previously projected values.

Feasibility and impact of a mental health chatbot on postpartum mental health: a randomized controlled trial

Perinatal mood disorders are common yet underdiagnosed and un- or undertreated. Barriers exist to accessing perinatal mental health services, including limited availability, time, and cost. Automated conversational agents (chatbots) can deliver evidence-based cognitive behavioral therapy content through text message-based conversations and reduce depression and anxiety symptoms in select populations. Such digital mental health technologies are poised to overcome barriers to mental health care access but need to be evaluated for efficacy, as well as for preliminary feasibility and acceptability among perinatal populations. To evaluate the acceptability and preliminary efficacy of a mental health chatbot for mood management in a general postpartum population. An unblinded randomized controlled trial was conducted at a tertiary academic center. English-speaking postpartum women aged 18 years or above with a live birth and access to a smartphone were eligible for enrollment prior to discharge from delivery hospitalization. Baseline surveys were administered to all participants prior to randomization to a mental health chatbot intervention or to usual care only. The intervention group downloaded the mental health chatbot smartphone application with perinatal-specific content, in addition to continuing usual care. Usual care consisted of routine postpartum follow up and mental health care as dictated by the patient's obstetric provider. Surveys were administered during delivery hospitalization (baseline) and at 2-, 4-, and 6-weeks postpartum to assess depression and anxiety symptoms. The primary outcome was a change in depression symptoms at 6-weeks as measured using two depression screening tools: Patient Health Questionnaire-9 and Edinburgh Postnatal Depression Scale. Secondary outcomes included anxiety symptoms measured using Generalized Anxiety Disorder-7, and satisfaction and acceptability using validated scales. Based on a prior study, we estimated a sample size of 130 would have sufficient (80%) power to detect a moderate effect size (d=.4) in between group difference on the Patient Health Questionnaire-9. A total of 192 women were randomized equally 1:1 to the chatbot or usual care; of these, 152 women completed the 6-week survey (n=68 chatbot, n=84 usual care) and were included in the final analysis. Mean baseline mental health assessment scores were below positive screening thresholds. At 6-weeks, there was a greater decrease in Patient Health Questionnaire-9 scores among the chatbot group compared to the usual care group (mean decrease=1.32, standard deviation=3.4 vs mean decrease=0.13, standard deviation=3.01, respectively). 6-week mean Edinburgh Postnatal Depression Scale and Generalized Anxiety Disorder-7 scores did not differ between groups and were similar to baseline. 91% (n=62) of the chatbot users were satisfied or highly satisfied with the chatbot, and 74% (n=50) of the intervention group reported use of the chatbot at least once in 2 weeks prior to the 6-week survey. 80% of study participants reported being comfortable with the use of a mobile smartphone application for mood management. Use of a chatbot was acceptable to women in the early postpartum period. The sample did not screen positive for depression at baseline and thus the potential of the chatbot to reduce depressive symptoms in this population was limited. This study was conducted in a general obstetric population. Future studies of longer duration in high-risk postpartum populations who screen positive for depression are needed to further understand the utility and efficacy of such digital therapeutics for that population.

Performance and Head-to-Head Comparison of Three Clinical Models to Predict Occurrence of Postthrombotic Syndrome: A Validation Study.

The SOX-PTS, Amin, and Méan models are three different clinical prediction scores stratifying the risk for postthrombotic syndrome (PTS) development in patients with acute deep vein thrombosis (DVT) of the lower limbs. Herein, we aimed to assess and compare these scores in the same cohort of patients. We retrospectively applied the three scores in a cohort of 181 patients (196 limbs) who participated in the SAVER pilot trial for an acute DVT. Patients were stratified into PTS risk groups using positivity thresholds for high-risk patients as proposed in the derivation studies. All patients were assessed for PTS 6 months after index DVT using the Villalta scale. We calculated the predictive accuracy for PTS and area under receiver operating characteristic (AUROC) curve for each model. The Méan model was the most sensitive (sensitivity 87.7%; 95% confidence interval [CI]: 77.2-94.5) with the highest negative predictive value (87.5%; 95% CI: 76.8-94.4) for PTS. The SOX-PTS was the most specific score (specificity 97.5%; 95% CI: 92.7-99.5) with the highest positive predictive value (72.7%; 95% CI: 39.0-94.0). The SOX-PTS and Méan models performed well for PTS prediction (AUROC: 0.72; 95% CI: 0.65-0.80 and 0.74; 95% CI: 0.67-0.82), whereas the Amin model did not (AUROC: 0.58; 95% CI: 0.49-0.67). Our data support that the SOX-PTS and Méan models have good accuracy to stratify the risk for PTS.

Diagnostic test accuracy meta-analysis of PRAME in distinguishing primary cutaneous melanomas from benign melanocytic lesions.

PRAME is a novel immunohistochemical marker that aids the diagnosis of melanocytic lesions. Diffuse PRAME positivity suggests melanoma, whereas benign naevi are negative or only weakly positive. However, the factual diagnostic accuracy of PRAME is not well established. Moreover, some studies have suggested that the threshold of 3+/50% positive cells may be more useful in practice than the most widely used cut-off (4+/75% of positive cells). Hence, we performed a systematic review and diagnostic accuracy meta-analysis to evaluate sensitivity, specificity, likelihood ratios and optimal threshold for PRAME in distinguishing benign melanocytic proliferations from melanomas. Twenty-six studies were enrolled into the meta-analysis. A total of 2915 melanocytic lesions were analysed. The optimal threshold for PRAME positivity was estimated at 3.11, which translates into 3+ in practice. Sensitivity and specificity calculated from SROC at the 3+ threshold were 0.735 (0.631-0.818) and 0.915 (0.834-0.958), respectively, compared to 0.679 (0.559-0.957) and 0.957 (0.908-0.981) at the 4+ cut-off. In subgroup analysis, the spitzoid subgroup was characterised by the lowest sensitivity and diagnostic odds ratio of PRAME. Our findings indicate that PRAME immunohistochemistry may serve as an ancillary marker to support the diagnosis of melanoma. Nevertheless, the accuracy of PRAME may be lower in spitzoid neoplasms. Our meta-analysis suggests that the 3+/50% threshold might be more useful in practice than the 4+/75% cut-off, as it shows higher sensitivity with retained satisfactory specificity.

Definition of Rainfall Thresholds for Landslides Using Unbalanced Datasets: Two Case Studies in Shaanxi Province, China

The Lueyang and Xunyang counties in the Shaanxi province (China) are highly susceptible to rainfall-induced landslides. Rainfall thresholds are the most used tool to predict the occurrence of rainfall-induced landslides over large areas. However, the definition of robust thresholds may be difficult for unbalanced datasets, for which the number of non-landslide observations is much higher than the number of landslide observations. This study aims at defining adequate rainfall thresholds for the two study areas using landslide datasets that are strongly unbalanced in terms of occurrences vs. non-occurrences. Two types of rainfall thresholds are determined using a frequentist method at several non-exceedance and exceedance probabilities, separately considering rainfall events responsible for landslides (positive thresholds) and rainfall events not responsible for landslides (negative thresholds). The comparison between the two sets of thresholds shows that the method based on non-triggering events allows defining rainfall thresholds characterized by lower uncertainties and a better performance than the ones defined considering the triggering events, in both the study areas. In particular, the best-performing thresholds are the negative threshold defined at 15% exceedance probability for the Lueyang county and the negative threshold defined at 20% exceedance probability for the Xunyang county.

Impact of Omicron Variant Infection on Assessment of Spike-Specific Immune Responses Using the EUROIMMUN Quan-T-Cell SARS-CoV-2 Assay and Roche Elecsys Anti-SARS-CoV-2-S

The currently prevailing variants of SARS-CoV-2 are subvariants of the Omicron variant. The aim of this study was to analyze the effect of mutations in the Spike protein of Omicron on the results Quan-T-Cell SARS-CoV-2 assays and Roche Elecsys anti-SARS-CoV-2 anti-S1. Omicron infected subjects ((n = 37), vaccinated (n = 20) and unvaccinated (n = 17)) were recruited approximately 3 weeks after a positive PCR test. The Quan-T-Cell SARS-CoV-2 assays (EUROIMMUN) using Wuhan and the Omicron adapted antigen assay and a serological test (Roche Elecsys anti-SARS-CoV-2 anti-S1) were performed. Using the original Wuhan SARS-CoV-2 IGRA TUBE, in 19 of 21 tested Omicron infected subjects, a positive IFNy response was detected, while 2 non-vaccinated but infected subjects did not respond. The Omicron adapted antigen tube resulted in comparable results. In contrast, the serological assay detected a factor 100-fold lower median Spike-specific RBD antibody concentration in non-vaccinated Omicron infected patients (n = 12) compared to patients from the pre Omicron era (n = 12) at matched time points, and eight individuals remained below the detection threshold for positivity. For vaccinated subjects, the Roche assay detected antibodies in all subjects and showed a 400 times higher median specific antibody concentration compared to non-vaccinated infected subjects in the pre-Omicron era. Our results suggest that Omicron antigen adapted IGRA stimulator tubes did not improve detection of SARS-CoV-2-specific T-cell responses in the Quant-T-Cell-SARS-CoV-2 assay. In non-vaccinated Omicron infected individuals, the Wuhan based Elecsys anti-SARS-CoV-2 anti-S1 serological assay results in many negative results at 3 weeks after diagnosis.

How do counselling trainees describe group process and does this change over time?

AbstractPersonal development groups or “group processes” are used in most counselling and psychotherapy trainings, but little is understood about how trainees change in their experience and descriptions of them over time. This study collected qualitative surveys (N = 70) from two groups of master's students (N = 35), at the mid‐ and end point of their first year of counselling training, to find out whether their descriptions of group process changed. We used content analysis to study the most common words and phrases used by trainee counsellors to describe group process and to monitor how positive, neutral and negative their descriptions were over time. We found a significant difference in the vocabulary and the ratio of positive to negative descriptions of group process at the midpoint of term, depending on the group the trainees were assigned to, with a levelling out of vocabulary words and positive and negative descriptions over time, converging towards a 70%–80% positive point at the end of term. Our results indicate that process groups need time to develop trainees above a positive threshold, by balancing group bonding against an ability to challenge and learn from difference, because individuals and groups start at different points in relation to their readiness and capacity for personal development. Further research should explore facilitation and trainee variables, as well as the impact of process groups on students' well‐being, because, while most of our students positively described the process, an important minority of students described negative experiences that were unresolved at the end of the study.

A73 EFFECT OF FECAL IMMUNOCHEMICAL TEST CUT-OFF LEVELS ON ADENOMA DETECTION RATE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract Background Adenoma detection rate (ADR) is higher after a positive fecal immunochemical test (FIT) compared to direct screening colonoscopy. Purpose This meta-analysis evaluated how ADR, the rates of advanced adenoma detection (AADR), colorectal cancer detection (CDR), and sessile serrated lesion detection (SSLDR) are affected by different FIT positivity thresholds. Method We searched MEDLINE, EMBASE, CINAHL, and EBM Reviews databases for studies reporting ADR, AADR, CDR, and SSLDR according to different FIT cut-off values in asymptomatic average-risk individuals aged 50 to 74 years old. Data were stratified according to sex, age, time to colonoscopy, publication year, continent, and FIT kit type. Study quality, heterogeneity, and publication bias were assessed. Result(s) Overall, 4280 articles were retrieved and fifty-seven studies were included (332,281 FIT-positive colonoscopies; mean cecal intubation 96.2%; mean age 60.7 years; male 52.1%). Mean ADR was 55.9% (95% CI 53.2% – 58.6%), while mean AADR, CDR, and SSLDR were 27.2% (95% CI 24.3% – 30.1%), 5.4% (95% CI 4.7% – 6.1%), and 3.0% (95% CI 1.7% – 4.6%), respectively. For each 20 μg Hb/g increase in FIT cut-off level, ADR increased by 2.87% (95% CI 1.70% – 4.05%, p &amp;lt; 0.01), AADR increased by 3.90% (95% CI 2.76% – 5.05%, p &amp;lt; 0.01) and CDR by 1.46% (95% CI 0.66% – 2.24%, p &amp;lt; 0.01). Many detection rates were greater amongst males and Europeans. Conclusion(s) ADRs in FIT-positive colonoscopies are influenced by the adopted FIT positivity threshold, and identified targets, importantly, proved to be higher than most current societal recommendations. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Scalable Charge-Based Compact Model for Drain Current in Fin-Shaped GaN HEMTs

We present a novel charge-based compact model for drain current in fin-shaped GaN high-electron-mobility transistors (Fin-HEMTs). A positive threshold voltage shift is observed in Fin-HEMTs due to better gate control of the channel. The combined effect of top and side gates on the channel charge density is studied with the help of detailed TCAD simulation. For the first time, a closed-form expression for 2-D electron gas (2-DEG) density in Fin-HEMTs is derived. The fin width dependence of the 2-DEG current is modeled in a unique way by considering the modified gate capacitance and threshold voltage in Fin-HEMTs. The total drain current is modeled as the sum of 2-DEG and double-gate field effect transistor (FET) currents. In addition, the total gate capacitance including the side-gate capacitance for fin structure is also formulated. The model is generic and can be used for different fin geometries using the proposed equivalent circuits as demonstrated. A fin-width-dependent thermal resistance model is proposed and included in the drain current model using a thermal subcircuit. The proposed model is completely analytical and does not require any iteration or fitting parameters in contrast to the available models discussed in the literature. Our model shows excellent agreement with the state-of-the-art experimental data.