Effect of annealing temperature on the structure and optical properties of ZnO thin films

The effect of annealing temperature on the microstructure, defects and optical properties of ZnO thin films are investigated using sol-gel based spin coating method for a range of annealing temperatures from 200∘C to 500∘C. The correlation among the microstructure, defects, impurity content and the optical band gap of films of thickness about 10-12 nm is elucidated. The particle size increases and the optical band gap reduces with the annealing temperature. At 200∘C, amorphous films were formed with particle size less than 10 nm with an optical band gap of about 3.41 eV. As the temperature increases the grain size increases and the defect, impurity content as well as the optical band gap reduces. This could be due to the reduction in the lattice strain. For an average grain size of about 35 nm and above, the band gap asymptotically approaches the theoretical value of ZnO (3.37 eV). The photoluminescence (PL) spectra show a systematic red-shift in the excitonic levels corresponding to the variation in the optical band-gap. The defect emission from Zn-vacancies is observed in the PL spectra and are further supported by the positron annihilation measurements.

Safety, feasibility, and short-term-outcome of anal endoscopic submucosal dissection for anal intraepithelial neoplasia: an option for focal lesions?

BACKGROUND

Anal intraepithelial neoplasia (AIN) appears in three different stages. AIN 1 and AIN 2 (p16 negative) are defined as low risk and unlikely to progress to invasive anal cancer. AIN 2 (p16 positive) and AIN 3 are of high risk and should be treated because progression rates to anal cancer are around 10% and treatment significantly reduces this risk. The correct treatment is still a matter of debate. Human papilloma virus (HPV) plays a role in the development of AIN. Our aim was to assess anal endoscopic dissection (aESD) as an intervention for AIN3.

METHODS

We retrospectively evaluated patients who underwent aESD for AIN 3 between December 2017 and March 2023. The interventional technique itself (duration, complications, size of specimen) and patient outcomes (recurrence, progression to anal cancer, re-intervention) were analyzed.

RESULTS

Fifteen patients with a median age of 52 years (23-78) underwent aESD for AIN 3. All tested specimens were positive for HPV. Median duration of intervention was 56.1 min, one delayed postinterventional bleeding occurred, and specimen size was 12.05 cm2. Median follow-up was 11.17 months. Three recurrences (20%) appeared: one was resected via biopsy and two were again treated with aESD. There was no progression to invasive anal cancer in the follow-up period.

CONCLUSIONS

Anal endoscopic submucosal dissection seems to be a safe and feasible treatment for AIN. Recurrences are seldom and can be treated again with the same method. Nevertheless, indications for resection in comparison to radiofrequency ablation, pharmacological therapy, and watch-and-wait strategy are still unclear.

TRIAL REGISTRATION

Ethics commission of Salzburg, Austria, EK-Nr. 1056/2023. Keywords: Endoscopic submucosal dissection, anal intraepithelial neoplasia, anal cancer.

Weight loss induced alleviation of sleep-disordered breathing is associated with improvement of non-alcoholic fatty liver disease

INTRODUCTION

Sleep-disordered breathing (SDB) and non-alcoholic fatty liver disease (NAFLD) are both common comorbidities in obese patients. Structured weight loss programs are effective and can reduce the incidence and severity of obesity-related comorbidities. The objective of the present analysis is to test whether weight loss induced alleviation of SDB is a predictor for improvement of NAFLD.

METHODS

Obese participants underwent a standardized non-surgical 3 months weight reduction program (800 kilocalories per day with low carbohydrate and fat content). Abdominal sonography for NAFLD (grade 0 to 3) and monitoring for SDB (defined as apnea-hypopnea index [AHI] ≥ 15/h) were performed at baseline and after 3 months. Alleviation of SDB was defined as a shift from AHI≥ 15/h to <15/h.

RESULTS

48 patients (48% female, age 42 ± 12 years, body-mass index 40.3 ± 8.1 kg/m2, AHI 14 ± 17/h, 85% NAFLD grade ≥1) participated in the weight loss program. In contrast to the no SDB group, in patients with SDB weight loss of 27.1 ±0 .9 kg (8.4 ± 2.8 kg/m2) after three months was paralleled by a reduction in AHI (-22 ± 17/h), prevalence of SDB (from 31% to 13%), and oxidized low-density lipoprotein (-13 ± 11 U/l). In individuals with preexisting SDB NAFLD grade improved more (2 versus 1, p<0.001) and was at a lower degree at 3 months than in those without SDB (0 versus 1, p = 0.015). In multivariable analysis models, SDB at baseline was associated with improvement of NAFLD grade (B 0.908; 95% CI 0.125, 1.691; p = 0.024), independently of age, sex, and BMI (each p>0.05, respectively). Decreasing BMI (B 0.16 [95%-CI 0.08; 0.23], p<0.001) and alleviation of SDB (B 0.90 [95%-CI 0.21; 1.58], p = 0.012) were independently associated with improvement of NAFLD grade.

CONCLUSION

Preexisting SDB and weight loss induced alleviation of SDB are predictors for improvement in NAFLD grade, independent of the extent of weight loss. SDB may contribute to the pathogenesis of NAFLD via SDB-induced oxidative stress and inflammation, but the causal mechanism remains unclear.

Evolution of point defects in pulsed-laser-melted Ge1-xSnxprobed by positron annihilation lifetime spectroscopy

Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy grown Ge1-xSnxfilms treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening - variable energy positron annihilation spectroscopy and variable energy positron annihilation lifetime spectroscopy are used to investigate the defect nanostructure in the Ge1-xSnxfilms exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, the positron annihilation spectroscopy analysis provides information about dislocations and Ge vacancies decorated by Sn atoms. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters.

Anti-HEV seroprevalence and rate of viremia in a German cohort of dogs, cats, and horses

Hepatitis E virus (HEV) genotype 3 infections in Germany are mainly transmitted zoonotically through the consumption of swine meat. Furthermore, there is evidence that pets might come into contact with HEV, but the relevance of companion animals as possible sources of HEV transmission in Germany still needs to be defined. A monitoring study was therefore carried out on dogs, cats, and horses from Germany. In total 365 serum samples from pets (124 dogs, 119 cats, and 122 horses) were tested for HEV by PCR and for anti-HEV antibodies by a commercial ELISA. The HEV seroprevalence determined by the sero-assay varied significantly between dogs (10%), cats (6%), and horses (2%). Liver injury-related enzymes, alanine transaminase (ALT), and aspartate transaminase (AST) showed no differences between HEV-positive or negative animals. None of the pet serum samples tested positive for PCR. This serological study suggests that dogs and cats are significantly exposed to HEV in Germany, while horses are of minor relevance.

Clonal associations of lymphocyte subsets and functional states revealed by single cell antigen receptor profiling of T and B cells in rheumatoid arthritis synovium

Rheumatoid arthritis (RA) is an autoimmune disease initiated by antigen-specific T cells and B cells, which promote synovial inflammation through a complex set of interactions with innate immune and stromal cells. To better understand the phenotypes and clonal relationships of synovial T and B cells, we performed single-cell RNA and repertoire sequencing on paired synovial tissue and peripheral blood samples from 12 donors with seropositive RA ranging from early to chronic disease. Paired transcriptomic-repertoire analyses highlighted 3 clonally distinct CD4 T cells populations that were enriched in RA synovium: T peripheral helper (Tph) and T follicular helper (Tfh) cells, CCL5+ T cells, and T regulatory cells (Tregs). Among these cells, Tph cells showed a unique transcriptomic signature of recent T cell receptor (TCR) activation, and clonally expanded Tph cells expressed an elevated transcriptomic effector signature compared to non-expanded Tph cells. CD8 T cells showed higher oligoclonality than CD4 T cells, and the largest CD8 T cell clones in synovium were highly enriched in GZMK+ cells. TCR analyses revealed CD8 T cells with likely viral-reactive TCRs distributed across transcriptomic clusters and definitively identified MAIT cells in synovium, which showed transcriptomic features of TCR activation. Among B cells, non-naive B cells including age-associated B cells (ABC), NR4A1+ activated B cells, and plasma cells, were enriched in synovium and had higher somatic hypermutation rates compared to blood B cells. Synovial B cells demonstrated substantial clonal expansion, with ABC, memory, and activated B cells clonally linked to synovial plasma cells. Together, these results reveal clonal relationships between functionally distinct lymphocyte populations that infiltrate RA synovium.

P05.01.B Distribution of the staining agent sodium-fluorescein in cerebral neoplasia - a comparison between intraoperative confocal laser endomicroscopy and in vitro fluorescence microscopy

Background

While conventional frozen sections and other ex vivo microscopy always come along with artefacts, in vivo confocal laser endomicroscopy (CLE) offers less invasive, less manipulated imaging of living tissues. Understanding the distribution of the staining agent sodium-fluorescein (NaFl) plays a key role in establishing in vivo CLE as a new opportunity for real-time transmitted, in vivo imaging.

By comparing the distribution of NaFl in in vivo and ex vivo CLE to conventional fluorescence microscopy of NaFl incubated tumor cell cultures we gain a better understanding of the staining mechanism.

Material and Methods

Sodium-fluorescein is the water-soluble sodium salt of fluorescein and is used as a fluorescent tracer in neurosurgery. The staining agent was applied intravenously at the beginning of the surgical procedure. In vivo CLE of the lesion was performed 30 to 50 minutes later and compared to ex vivo CLE imaging and conventional fluorescence microscopy. In addition, different tumor cell lines derived from malignant gliomas and carcinomas, respectively, were incubated with NaFl in vitro and the uptake of the fluorescent dye was monitored over time.

Results

From initial results, the intraoperative images showed specific fluorescein distribution depending on the architecture of the tumor entity. In most cases, glial tumors demonstrated higher accumulation of the staining agent in the extracellular tumor matrix, whereas the cells of carcinoma metastases appeared to take up NaFl intracellularly. These results were corroborated by NaFl uptake in cell culture experiments.

Compared to ex vivo CLE, in vivo imaging offered a faster assessment of the tissue, brighter images and higher staining levels. Due to movement artefacts and the narrow intraoperative imaging time frame, in vivo CLE images were sometimes impaired by lower image quality.

Conclusion

The specific distribution of the fluorescent agent NaFl allowed for a discrimination between the different neoplastic entities. Images from in vivo and ex vivo confocal laser endomicroscopy showed NaFl uptake in concordance with the results of NaFl incubated cell cultures.

Intraoperative, in vivo confocal laser endomicroscopy shows promising first results in the understanding of brain tumor histomorphology in situ. Being faster and less manipulated by artefacts than ex vivo investigations, it opens up wider opportunities for research and intraoperative diagnostics.

OP0243 OSTEOPOROSIS CASE-FINDING IN PEOPLE UNDERGOING ROUTINE DIAGNOSTIC CT SCANS ALMOST TRIPLED THE RATE OF OSTEOPOROSIS TREATMENT AT 12 MONTHS. A RANDOMISED, MULTI-CENTRE FEASIBILITY STUDY USING WAITING ROOM FRAX, OPPORTUNISTIC CT BONE DENSITY AND VERTEBRAL FRACTURE ASSESSMENT VERSUS USUAL CARE

Background

Up to 40% of all diagnostic computed tomography (CT) scans include views of the spine or hips. Among older people, osteoporosis or vertebral fractures have been found in 30% of such CT scans. Our ‘PHOENIX’ intervention repurposes CT scans taken for other reasons to identify fractures and measure bone density as an ‘added extra’. Early detection and treatment of osteoporosis in CT-attending patients could improve health outcomes.

Objectives

To determine the feasibility and efficacy of PHOENIX versus usual care in a multi-centre, randomised, pragmatic study conducted in Eastern England involving our Cambridge Specialist Hospital ‘hub’ and four regional General Hospital ‘spokes’.

Methods

Women ≥65 and men ≥75 years attending for routine diagnostic CT scans were invited to participate via a novel consent form incorporating FRAX Fracture Risk Assessment questions. After calculating their FRAX 10-year risk score, higher risk patients were block randomised (1:1:1) to Group 1) PHOENIX intervention, 2) Active Control, where the GP was sent the patients’ FRAX answers only, or 3) Usual Care where data were only analysed after 13 months had elapsed. The CT scans of high FRAX risk patients in Group 1 were retrieved by the Cambridge team using NHS Connecting for Health (Burnbank, UK). The team performed vertebral fracture assessment and measured bone density using QCT Pro (Mindways, USA). They added patient-specific treatment and investigation management advice from ‘drop down’ menus before results were reviewed by a physician, authorised and sent to general practitioners (GPs). Baseline CT scans from groups 2 and 3 were assessed in the same way after 13 months to ensure no patient with osteoporosis/fractures was neglected long term. Assuming 25% attrition, the study was powered to find a superior osteoporosis treatment rate in Group 1 (estimated 20%) versus 16% (Active Control) and 5% (Usual Care). Co-primary feasibility endpoints were the ability to a) randomise 375 patients within 10 months and b) retain 75% of survivors able to complete a 1-year bone health outcome questionnaire. Secondary outcomes included osteoporosis/vertebral fracture identification rates and osteoporosis treatment rates. Stakeholder acceptability and economic aspects will be reported separately.

Results

From 1828 invites, 595 participants consented to participate of whom 213 were excluded due to ‘low’ FRAX score. Mortality at 12 months was 20%. Both feasibility objectives were achieved: 1) 382 people were randomised within 10 months; 2) 84.4% of survivors at 1 year (95%CI: 80.5, 88.3) were successfully followed-up. Groups were well matched at baseline. The average age of 375 patients (334 female, 41 male) was 75.2 years (74.6, 75.9). Osteoporosis of the hip/spine was present in 41% of 362 analysable CT scans. From the 264 spines that were suitable for VFA, 20% (n=53) were found to have vertebral fractures, with 8.3% having multiple vertebral fractures (n=22). Osteoporosis treatment was reported in 8.5% of Usual Care group (2.9, 14.2) and 24.2% (15.4, 33.0) of PHOENIX group participants, while in the Active Control group (FRAX only) it was 18.8% (10.9, 26.6 p=0.021). In the PHOENIX group, a recommendation to treat was sent to 50 patients’ GPs at baseline. Only 18 of the 50 patients (36%) were found to be taking osteoporosis treatment 12 months after this advice was sent.

Conclusion

Osteoporosis treatment rates were almost tripled by screening patients attending for routine diagnostic CT scans with waiting room FRAX, CT-bone densitometry and vertebral fracture analysis.

Acknowledgements

This project is funded by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG-0816-20027) and by the Cambridge NIHR Biomedical Research Centre (BRC-1215-20014). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. Funding is in place to 31.03.2022. Three individuals, Mr Jeremy Dearling, Mrs Tessa Plume and Dr Ann Frost joined our trial group as PPI representatives; they were specifically involved in patient documentation design (particularly the PHOENIX pack, informed consent form which facilitated consent without having a researcher present) and contributed to suggestions for increasing patient recruitment and follow up.

Disclosure of Interests

None declared

Manipulating magnetic and magnetoresistive properties by oxygen vacancy complexes in GCMO thin films

The effect ofin situannealing is investigated in Gd_0.1Ca_0.9MnO₃(GCMO) thin films in oxygen and vacuum atmospheres. We show that the reduction of oxygen content in GCMO lattice by vacuum annealing induced more oxygen complex vacancies in both subsurface and interface regions and larger grain domains when compared with the pristine one. Consequently, the double exchange interaction is suppressed and the metallic-ferromagnetic state below Curie temperature turned into spin-glass insulating state. In contrast, the magnetic and resistivity measurements show that the oxygen treatment increases ferromagnetic phase volume, resulting in greater magnetization (M_S) and improved magnetoresistivity properties below Curie temperature by improving the double exchange interaction. The threshold field to observe the training effect is decreased in oxygen treated film. In addition, the positron annihilation spectroscopy analysis exhibits fewer open volume defects in the subsurface region for oxygen treated film when compared with the pristine sample. These results unambiguously demonstrate that the oxygen treated film with significant spin memory and greater magnetoresistance can be a potential candidate for the future memristor applications.

[Comparison of catheter-associated quality of life in external urinary diversion: nephrostomy vs. suprapubic catheter]

Einleitung

Die katheterbezogene Lebensqualität (LQ) bei Nephrostomieträgern wurde bisher noch nie systematisch untersucht. Dies sollte nun erstmalig vergleichend mit einer ebenfalls externen Urinableitung, dem suprapubischen Katheter, geschehen.

Methodik

Das die katheterbezogene LQ untersuchende Assessment nach Mary Wilde wurde bei Patienten mit perkutaner Nephrostomie (PCN) in lebenslanger Intention und minimaler Liegedauer von 3 Monaten vorgelegt.

Ergebnisse

Es zeigte sich insgesamt bei 66 Patienten (davon 42 mit unilateraler PCN) mit einem Punktwert von median 4,0 auf einer Skala von 0–5 eine nur moderat eingeschränkte katheterbezogene LQ. Diese wurde insgesamt und in allen Domänen schlechter als bei Patienten mit suprapubischem Katheter (SPK) bewertet, bei denen sich ein Score von 4,3 im Median fand. Signifikant waren die Unterschiede in den Einzelitems „Gefühl der Erniedrigung“, „Konflikte mit ärztlichem oder pflegerischem Personal“, „Angst vor schmerzhaften Katheterwechseln“, „Gefühl als kranke Person“, „Behinderungen in Aktivitäten des täglichen Lebens“ und „Besorgnis, nicht alles tun zu können, was ich mag“. Ebenso ergaben sich bei PCN-Trägern signifikant häufiger Angst vor Katheterlecks und Uringeruch. Die Anzahl der einliegenden PCN und die Grunderkrankung spielten für die Beurteilung der LQ keine Rolle.

Schlussfolgerung

Erstmals wurde die katheterassoziierte LQ, die sich bei PCN-Trägern nur moderat eingeschränkt fand, mit einem validierten Assessment quantitativ eingeordnet. Die Angabe der Betroffenen, sich als „krank“ und in der Ausübung von Aktivitäten des täglichen Lebens „behindert“ zu fühlen und die Angst vor Urinleckagen und schmerzhaften Wechseln sollten Ansporn für eine sorgfältige Indikationsstellung und technisch korrekte Katheterwechsel sein.

[Guidelines for consultations regarding incontinence care products]

An investigation of the German consumer organisation "Stiftung Warentest" in 2017 confirmed significant deficiencies in the information, advice and supply of incontinence care products received by urinary incontinence patients. The German Society of Urology (DGU) thereupon drafted and later published guidelines concerning the consultation of patients in the context of incontinence care. Important aspects of the consultation process include the determination of the type of incontinence as well as its severity, clinical examination, and advice regarding possible curative treatments. However, the advice appointment takes centre stage and should ideally be conducted by a qualified person in a separate room granting sufficient privacy and time. Furthermore, repeated supply of a selection of samples for differing degrees and types of incontinence, accommodating the patient's individual preferences and anatomical features, is crucial in order to ensure optimal incontinence care. In the case of commercial health care service providers, transparency relating to the financial implications of e.g. expensive products is key, which is what has been intended by German health insurance providers. The new guidelines concerning urinary incontinence care consultation constitute a step towards the improvement and structuring of processes in the consultation regarding, and the supply of, incontinence care products.

Al2O3 co-doped with Cr3+ and Mn4+, a dual-emitter probe for multimodal non-contact luminescence thermometry

Luminescence probes that facilitate multimodal non-contact measurements of temperature are of particular interest due to the possibility of cross-referencing results across different readout techniques. This intrinsic referencing is an essential addition that enhances accuracy and reliability of the technique. A further enhancement of sensor performance can be achieved by using two luminescent ions acting as independent emitters, thereby adding in-built redundancy to non-contact temperature sensing, using a single readout technique. In this study we combine both approaches by engineering a material with two luminescent ions that can be independently probed through different readout modes of non-contact temperature sensing. The approach was tested using Al₂O₃ co-doped with Cr³⁺ and Mn⁴⁺, exhibiting sharp emission lines due to ²E → ⁴A₂ transitions. The temperature sensing performance was examined by measuring three characteristics: temperature-induced changes of the intensity ratio of the emission lines, their spectral position, and the luminescence decay time constant. The processes responsible for the changes with temperature of the measured luminescence characteristics are discussed in terms of relevant models. By comparing temperature resolutions achievable by different modes of temperature sensing it is established that in Al₂O₃-Cr,Mn spectroscopic methods provide the best measurement accuracy over a broad temperature range. A temperature resolution better than ±2.8 K can be achieved by monitoring the luminescence intensity ratio (40-145 K) and the spectral shift of the R-line of Mn⁴⁺ (145-300 K range).

[Quality of life for wearers of a suprapubic or transurethral bladder catheter as lifelong permanent care]

Hintergrund

Die Anlage eines transurethralen Dauerkatheters (DK) oder suprapubischen Harnblasenkatheters (SPK) in lebenslanger Indikation stellt einen Eingriff mit relevanten Komplikationen, Komorbiditäten und möglichen Auswirkungen auf die katheterassoziierte Lebensqualität des Betroffenen dar. Letztere wurde aber bisher noch nicht untersucht.

Methodik

Zur Anwendung kam ein validiertes Assessment zur katheterbezogenen Lebensqualität mit 25 Items in 5 Domänen. Befragt wurden im Rahmen eines Katheterwechsels Patienten mit einem DK oder SPK in lebenslanger Intention, die diesen mindestens 3 Monate trugen.

Ergebnisse

Fragebögen von 357 Patienten, davon 260 Männer und 97 Frauen, 193 mit SPK und 162 mit DK (2 ohne Angabe) lagen vor. Patienten mit DK waren mit 78,9 ± 11,1 Jahren signifikant älter als solche mit SPK mit 74,4 ± 12,6 Jahren (p < 0,001). Der mittlere Gesamtlebensqualitätsscore lag bei 4,1 ± 0,9 Punkten auf einer Skala von 1 (maximal beeinträchtigte Lebensqualität) bis 5 (keine Beeinträchtigung der Lebensqualität). Es zeigten sich u. a. mit niedrigeren Scores eine vermehrte Angst vor Katheterlecks, Angst vor Uringeruch und Harnwegsinfektionen und vor schmerzhaften Katheterwechseln. Diese Sorgen waren v. a. bei Frauen, solchen mit Harninkontinenz, Trägern eines Katheters ≥ 18 Ch und bei Patienten < 70 Jahren vorhanden. Frauen mit einem SPK wiesen eine schlechtere Bewertung ihrer Lebensqualität als Männer mit SPK auf.

Schlussfolgerung

Die gefundenen Ergebnisse sollten in die Aufklärung zu einer lebenslangen Katheterableitung einfließen bzw. im Kontext möglicher Alternativen wie z. B. einer operativen Desobstruktion oder einer Hilfsmittelversorgung mit dem Patienten bzw. Betreuungspersonen besprochen werden.

Zusatzmaterial online

Die Online-Version dieses Beitrags (10.1007/s00120-021-01642-1) enthält weitere Tabellen mit detaillierten Ergebnissen der Fragen der 5 abgefragten Domänen.

LGG-15. COMPREHENSIVE ANALYSIS OF MYB/MYB1-ALTERED GLIOMAS: A MULTI-INSTITUTIONAL EXPERIENCE OF 33 GLIOMAS

Background

Pediatric diffuse gliomas harbor recurrent genetic alterations, including those in MYB and MYBL1. Regardless of histopathologic classification, low-grade diffuse gliomas with MYB/MYBL1 alterations represent a single disease entity. Additional insight is needed to define optimal therapeutic strategies for these tumors.

Methods

We retrospectively reviewed gliomas with MYB or MYB1L alterations treated or referred for pathologic review at St. Jude Children’s Research Hospital (St. Jude). Tumor specimens were centrally reviewed. Molecular characterization and clinical data were collated from St. Jude and referring institutions.

Results

Thirty-three patients were identified. Two tumors had MYBL1 alterations, while 31 had MYB alterations. MYB-QKI fusion was the most common alteration. Eighteen (55%) were male. The median age at diagnosis was 5 years (range, 0–40 years). Most tumors were in the cerebral cortex (22/33), and the most common presentation was seizures (16/33). Three patients (9%) presented with hydrocephalus and required cerebrospinal fluid diversion. Two patients (6%) presented with metastatic disease. Gross-total resection was achieved in 15 patients (45%). Of the 7 patients receiving cytotoxic chemotherapy, no substantial response was observed. Of the 6 patients who received RT, one had disease progression. The median follow-up was 5.9 years. The 5-year event-free survival was 88.1%, while the 5-year overall survival was 96.3%. Two patients died, one of unclear cause and one of treatment-related acute myelogenous leukemia. Using log-rank tests, no difference in outcomes was observed based on molecular characteristics, degree of resection, metastatic status, or treatment modality.

Conclusions

Although tumors with MYB and MYBL1 alterations present with varying molecular and clinical features, they represent a group of tumors with favorable outcomes. Further characterization is required to identify the subgroup of tumors with a higher propensity for progression.

Tuned AFM-FM coupling by the formation of vacancy complex in Gd0.6Ca0.4MnO3thin film lattice

The effect ofin situoxygen and vacuum annealings on the low bandwidth manganite Gd_1-xCa_xMnO₃(GCMO) thin film withx= 0.4 was investigated. Based on the magnetic measurements, the AFM-FM coupling is suppressed by the vacuum annealing treatment via destroying the double exchange interaction and increasing the unit cell volume by converting the Mn⁴⁺to the Mn³⁺. Consequently, resistance increases significantly compared to pristine film. The results are explained by a model obtained from the positron annihilation studies, where the vacuum annealing increased the annihilation lifetime in A and B sites due to the formation of vacancy complexesV_A,B-V_O, which was not the case in the pristine sample. The positron annihilation analysis indicated that most of the open volume defects have been detected in the interface region rather than on the subsurface layer and this result is confirmed by detailed x-ray reflection analysis. On the other hand, the effect of oxygen annealing on the unit cell volume and magnetization was insignificant. This is in agreement with positron annihilation results which demonstrated that the introduction of oxygen does not change the number of cation vacancies significantly. This work demonstrates that the modification of oxygen vacancies and vacancy complexes can tune magnetic and electronic structure of the epitaxial thin films to provide new functionalities in future applications.

Evaluation of the automated LIAISON® SARS-CoV-2 TrimericS IgG assay for the detection of circulating antibodies

OBJECTIVES

COVID-19 has brought about tests from many manufacturers. While molecular and rapid antigen tests are targeted for early diagnosis, immunoassays have a larger role in epidemiological studies, understanding longitudinal immunity, and in vaccine development and response.

METHODS

The performance of the LIAISON^® SARS-CoV-2 TrimericS IgG assay was evaluated against the Beckman ACCESS SARS-CoV-2 IgG assay in New Mexico, and against the Siemens ADVIA Centaur COV2G assay in New York. Discordant samples were parsed using a microneutralization assay.

RESULTS

A SARS-CoV-2 antibody positivity rate of 23.8% was observed in the samples tested in New York (September 2020), while in the same month the positivity rate was 1.5% in New Mexico. Positive and negative agreement were 67.6% (95% CI 49.5-82.6%) and 99.8% (95% CI 99.5-99.9%), respectively, with the Beckman test, and 98.0% (95% CI 95.7-99.3%) and 94.8% (95% CI 93.4-96.0%), respectively, with the Siemens test. Receiver operating characteristic analysis for the detection of SARS-CoV-2 antibodies discloses an AUC, area under the curve, of 0.996 (95% CI 0.992-0.999) for the LIAISON^® SARS-CoV-2 TrimericS IgG assay. The criterion associated to the Youden Index was determined to be >12.9 kAU/L with a sensitivity of 99.44% and a specificity of 99.82%.

CONCLUSIONS

The LIAISON^® SARS-CoV-2 TrimericS IgG assay is highly sensitive and specific. The balance of these parameters, without emphasis on high specificity alone, is particularly important when applied to high prevalence populations, where a highly sensitive assay will result in reporting a lower number of false negative subjects.

An experimental investigation of light emission produced in the process of positronium formation in matter

The excess energy emitted during the positronium (Ps) formation in condensed matter may be released as light. Spectroscopic analysis of this light can be a new method of studying the electronic properties of materials. We report the first experimental attempt, according to our knowledge, to verify the existence of this emission process. As a result, the possibility of the emission of photons during Ps formation is within the experimental uncertainty in two different solids: an n-alkane and porous silica. However, it seems that the Ps formation on the alkane surface is not accompanied by the emission of photons with energy in the detection range of 1.6-3.8 eV. Various processes that can influence the energy of the photon emitted during the Ps formation are discussed to elucidate this issue. To aid future experiments, equations were developed to estimate the expected ratio of light emission events to annihilation events with the presence or absence of a photon during the Ps formation.

Diagnosis and management of tropomyosin receptor kinase (TRK) fusion sarcomas: expert recommendations from the World Sarcoma Network

Sarcomas are a heterogeneous group of malignancies with mesenchymal lineage differentiation. The discovery of neurotrophic tyrosine receptor kinase (NTRK) gene fusions as tissue-agnostic oncogenic drivers has led to new personalized therapies for a subset of patients with sarcoma in the form of tropomyosin receptor kinase (TRK) inhibitors. NTRK gene rearrangements and fusion transcripts can be detected with different molecular pathology techniques, while TRK protein expression can be demonstrated with immunohistochemistry. The rarity and diagnostic complexity of NTRK gene fusions raise a number of questions and challenges for clinicians. To address these challenges, the World Sarcoma Network convened two meetings of expert adult oncologists and pathologists and subsequently developed this article to provide practical guidance on the management of patients with sarcoma harboring NTRK gene fusions. We propose a diagnostic strategy that considers disease stage and histologic and molecular subtypes to facilitate routine testing for TRK expression and subsequent testing for NTRK gene fusions.

A new mechanism for void-cascade interaction from nondestructive depth-resolved atomic-scale measurements of ion irradiation-induced defects in Fe

The nondestructive investigation of single vacancies and vacancy clusters in ion-irradiated samples requires a depth-resolved probe with atomic sensitivity to defects. The recent development of short-pulsed positron beams provides such a probe. Here, we combine depth-resolved Doppler broadening and positron annihilation lifetime spectroscopies to identify vacancy clusters in ion-irradiated Fe and measure their density as a function of depth. Despite large concentrations of dislocations and voids in the pristine samples, positron annihilation measurements uncovered the structure of vacancy clusters and the change in their size and density with irradiation dose. When combined with transmission electron microscopy measurements, the study demonstrates an association between the increase in the density of small vacancy clusters with irradiation and a remarkable reduction in the size of large voids. This, previously unknown, mechanism for the interaction of cascade damage with voids in ion-irradiated materials is a consequence of the high porosity of the initial microstructure.

Integration of the M6 Cyberknife in the Moderato Monte Carlo platform and prediction of beam parameters using machine learning

PURPOSE

This work describes the integration of the M6 Cyberknife in the Moderato Monte Carlo platform, and introduces a machine learning method to accelerate the modelling of a linac.

METHODS

The MLC-equipped M6 Cyberknife was modelled and integrated in Moderato, our in-house platform offering independent verification of radiotherapy dose distributions. The model was validated by comparing TPS dose distributions with Moderato and by film measurements. Using this model, a machine learning algorithm was trained to find electron beam parameters for other M6 devices, by simulating dose curves with varying spot size and energy. The algorithm was optimized using cross-validation and tested with measurements from other institutions equipped with a M6 Cyberknife.

RESULTS

Optimal agreement in the Monte Carlo model was reached for a monoenergetic electron beam of 6.75 MeV with Gaussian spatial distribution of 2.4 mm FWHM. Clinical plan dose distributions from Moderato agreed within 2% with the TPS, and film measurements confirmed the accuracy of the model. Cross-validation of the prediction algorithm produced mean absolute errors of 0.1 MeV and 0.3 mm for beam energy and spot size respectively. Prediction-based simulated dose curves for other centres agreed within 3% with measurements, except for one device where differences up to 6% were detected.

CONCLUSIONS

The M6 Cyberknife was integrated in Moderato and validated through dose re-calculations and film measurements. The prediction algorithm was successfully applied to obtain electron beam parameters for other M6 devices. This method would prove useful to speed up modelling of new machines in Monte Carlo systems.

Molecular point-of-care testing for influenza A/B and respiratory syncytial virus: comparison of workflow parameters for the ID Now and cobas Liat systems

Aims

Point-of-care (POC) tests for influenza and respiratory syncytial virus (RSV) offer the potential to improve patient management and antimicrobial stewardship. Studies have focused on performance; however, no workflow assessments have been published comparing POC molecular tests. This study compared the Liat and ID Now systems workflow, to assist end-users in selecting an influenza and/or RSV POC test.

Methods

Staffing, walk-away and turnaround time (TAT) of the Liat and ID Now systems were determined using 40 nasopharyngeal samples, positive for influenza or RSV. The ID Now system requires separate tests for influenza and RSV, so parallel (two instruments) and sequential (one instrument) workflows were evaluated.

Results

The ID Now ranged 4.1–6.2 min for staffing, 1.9–10.9 min for walk-away and 6.4–15.8 min for TAT per result. The Liat ranged 1.1–1.8 min for staffing, 20.0–20.5 min for walk-away and 21.3–22.0 min for TAT. Mean walk-away time comprised 38.0% (influenza positive) and 68.1% (influenza negative) of TAT for ID Now and 93.7% (influenza/RSV) for Liat. The ID Now parallel workflow resulted in medians of 5.9 min for staffing, 9.7 min for walk-away and 15.6 min for TAT. Assuming prevalence of 20% influenza and 20% RSV, the ID Now sequential workflow resulted in medians of 9.4 min for staffing, 17.4 min for walk-away, and 27.1 min for TAT.

Conclusions

The ID Now and Liat systems offer different workflow characteristics. Key considerations for implementation include value of both influenza and RSV results, clinical setting, staffing capacity, and instrument(s) placement.

B-54 Insights into a Novel Integrated Screening Clinic: Parent Perceptions of Emotional Functioning in Acute Recovery Phase Following Pediatric Neurocritical Care

Objective

Children with traumatic brain injury (TBI) requiring neurocritical care are at high risk for neurocognitive, emotional, physical, and psychosocial difficulties, collectively known as Post-Intensive Care Syndrome. Our study sought to characterize parent ratings of emotional functioning in the acute recovery phase based upon mechanism of injury.

Method

Twenty children (Mdn = 12.6 years, IQR = 9-15; 65% male) were screened as part of a multidisciplinary follow-up clinic 1-month following hospital discharge. Emotional functioning was assessed using PROMIS Parent Proxy Report for Anxiety and Depression. A brief neurocognitive battery estimated presence of cognitive impairment. MANCOVA was used to compare emotional functioning across injury mechanism (high velocity injury [HVI], 65%; fall, 35%).

Results

Groups did not differ on age, gender, and presence of cognitive impairment. After controlling for severity, mechanism of injury had a significant effect on both anxiety (p = .026) and depression (p = .004). The HVI group had mildly elevated anxiety (M = 50.5, SD = 12.2) and depression (M = 54.2, SD = 10.6) scores, while the fall group had anxiety (M = 38.0, SD = 6.2) and depression (M = 39.0, SD = 7.3) scores within normal limits.

Conclusions

In the acute recovery phase following TBI, anxiety and depression symptoms are more common after HVI than falls, even when controlling for severity of injury. The HVI group includes injuries resulting from motor vehicle accidents which may have a broader impact on the family and may explain higher rates of emotional distress in this patient group compared to other mechanisms of TBI. Additional research is needed to further explore variables related to emotional functioning following TBI and how they change over the course of recovery.

On defects' role in enhanced perpendicular magnetic anisotropy in Pt/Co/Pt, induced by ion irradiation

Modifications of magnetic and magneto-optical properties of Pt/Co(d _Co )/Pt upon Ar⁺ irradiation (with energy 1.2, 5 and 30 keV) and fluence, F at the range from 2 · 10¹³-2 · 10¹⁶ Ar⁺ cm^-2) were studied. Two 'branches' of increased perpendicular magnetic anisotropy (PMA) and enhanced magneto-optical response are found on 2D (d _Co , F) diagrams. The difference in F between 'branches' is driven by ion energy. Structural features correlated with magnetic properties have been analysed thoroughly by x-ray diffraction, Rutherford backscattering spectrometry and positron annihilation spectroscopy. Experimental results are in agreement with TRIDYN numerical calculations of irradiation-induced layers intermixing. Our work discusses particularly structural factors related to crystal lattice defects and strain, created and modified by irradiation, co-responsible for the increase in the PMA.

Laboratory comparison between cell cytotoxicity neutralization assay and ultrasensitive single molecule counting technology for detection of Clostridioides difficile toxins A and B, PCR, enzyme immunoassays, and multistep algorithms

Diagnostic tests for Clostridioides difficile infection (CDI) lack either specificity (nucleic acid amplification tests) or sensitivity (enzyme immunoassays; EIAs). The performance of the Singulex Clarity® C. diff toxins A/B assay was compared to cell cytotoxicity neutralization assay. Testing was also performed using an EIA for glutamate dehydrogenase (GDH) and C. difficile toxins A and B (C. Diff Quik Chek Complete®), polymerase chain reaction (PCR) (BD MAX™ Cdiff Assay), and 2 multistep algorithms: algorithm 1 (discordant GDH/toxin results arbitrated by PCR) and algorithm 2 (PCR-positive samples tested with toxin EIA). The Clarity assay and PCR both had 97% sensitivity, while specificity was 100% for Clarity and 79% for PCR. Algorithm 1 yielded 41% discordant results, and both toxin EIA and algorithm 2 had 58% sensitivity. Median toxin concentrations, as measured by the Clarity C. difficile toxin assay, were 3590, 11.5, 0.4, and 0 pg/mL for GDH+/toxin+, GDH+/toxin-/PCR+, GDH+/toxin-/PCR-, and GDH-/toxin- samples, respectively (P < 0.001). The Clarity assay may offer a single-test solution for CDI.

Elevated age-related cortical iron, ferritin and amyloid plaques in APPswe/PS1ΔE9 transgenic mouse model of Alzheimer’s disease

Iron is very important element for functioning of the brain. Its concentration changes with aging the brain or during disease. The aim of our work was the histological examination of content of ferritin and free iron (unbound) in brain cortex in association with Aβ plaques from their earliest stages of accumulation in amyloid plaque forming APP/PS1 transgenic mice. Light microscopy revealed the onset of plaques formation at 8-monthage. Detectable traces of free iron and no ferritin were found around plaques at this age, while the rate of their accumulation in and around Aβ plaques was elevated at 13 months of age. Ferritin accumulated mainly on the edge of Aβ plaques, while the smaller amount of free iron was observed in the plaque-free tissue, as well as in and around Aβ plaques. We conclude that free iron and ferritin accumulation follows the amyloid plaques formation. Quantification of cortical iron and ferritin content can be an important marker in the diagnosis of Alzheimer’s disease.

1088. Ultrasensitive Detection of C. difficile Toxins in Stool Using Single Molecule Counting Technology: A Multicenter Study for Evaluation of Clinical Performance

Background

Methods

Results

Conclusion

Disclosures