Histological classification of canine and feline lymphoma using a modular approach based on deep learning and advanced image processing

Histopathological examination of tissue samples is essential for identifying tumor malignancy and the diagnosis of different types of tumor. In the case of lymphoma classification, nuclear size of the neoplastic lymphocytes is one of the key features to differentiate the different subtypes. Based on the combination of artificial intelligence and advanced image processing, we provide a workflow for the classification of lymphoma with regards to their nuclear size (small, intermediate, and large). As the baseline for our workflow testing, we use a Unet++ model trained on histological images of canine lymphoma with individually labeled nuclei. As an alternative to the Unet++, we also used a publicly available pre-trained and unmodified instance segmentation model called Stardist to demonstrate that our modular classification workflow can be combined with different types of segmentation models if they can provide proper nuclei segmentation. Subsequent to nuclear segmentation, we optimize algorithmic parameters for accurate classification of nuclear size using a newly derived reference size and final image classification based on a pathologists-derived ground truth. Our image classification module achieves a classification accuracy of up to 92% on canine lymphoma data. Compared to the accuracy ranging from 66.67 to 84% achieved using measurements provided by three individual pathologists, our algorithm provides a higher accuracy level and reproducible results. Our workflow also demonstrates a high transferability to feline lymphoma, as shown by its accuracy of up to 84.21%, even though our workflow was not optimized for feline lymphoma images. By determining the nuclear size distribution in tumor areas, our workflow can assist pathologists in subtyping lymphoma based on the nuclei size and potentially improve reproducibility. Our proposed approach is modular and comprehensible, thus allowing adaptation for specific tasks and increasing the users’ trust in computer-assisted image classification

Adsorption and reaction of CO on (Pd–)Al2O3 and (Pd–)ZrO2: vibrational spectroscopy of carbonate formation

γ-Alumina is widely used as an oxide support in catalysis, and palladium nanoparticles supported by alumina represent one of the most frequently used dispersed metals. The surface sites of the catalysts are often probed via FTIR spectroscopy upon CO adsorption, which may result in the formation of surface carbonate species. We have examined this process in detail utilizing FTIR to monitor carbonate formation on γ-alumina and zirconia upon exposure to isotopically labelled and unlabelled CO and CO2. The same was carried out for well-defined Pd nanoparticles supported on Al2O3 or ZrO2. A water gas shift reaction of CO with surface hydroxyls was detected, which requires surface defect sites and adjacent OH groups. Furthermore, we have studied the effect of Cl synthesis residues, leading to strongly reduced carbonate formation and changes in the OH region (isolated OH groups were partly replaced or were even absent). To corroborate this finding, samples were deliberately poisoned with Cl to an extent comparable to that of synthesis residues, as confirmed by Auger electron spectroscopy. For catalysts prepared from Cl-containing precursors a new CO band at 2164 cm−1 was observed in the carbonyl region, which was ascribed to Pd interacting with Cl. Finally, the FTIR measurements were complemented by quantification of the amount of carbonates formed via chemisorption, which provides a tool to determine the concentration of reactive defect sites on the alumina surface

Nuclear Morphometry using a Deep Learning-based Algorithm has Prognostic Relevance for Canine Cutaneous Mast Cell Tumors

Variation in nuclear size and shape is an important criterion of malignancy for many tumor types; however, categorical estimates by pathologists have poor reproducibility. Measurements of nuclear characteristics (morphometry) can improve reproducibility, but manual methods are time consuming. In this study, we evaluated fully automated morphometry using a deep learning-based algorithm in 96 canine cutaneous mast cell tumors with information on patient survival. Algorithmic morphometry was compared with karyomegaly estimates by 11 pathologists, manual nuclear morphometry of 12 cells by 9 pathologists, and the mitotic count as a benchmark. The prognostic value of automated morphometry was high with an area under the ROC curve regarding the tumor-specific survival of 0.943 (95% CI: 0.889 - 0.996) for the standard deviation (SD) of nuclear area, which was higher than manual morphometry of all pathologists combined (0.868, 95% CI: 0.737 - 0.991) and the mitotic count (0.885, 95% CI: 0.765 - 1.00). At the proposed thresholds, the hazard ratio for algorithmic morphometry (SD of nuclear area $\geq 9.0 \mu m^2$) was 18.3 (95% CI: 5.0 - 67.1), for manual morphometry (SD of nuclear area $\geq 10.9 \mu m^2$) 9.0 (95% CI: 6.0 - 13.4), for karyomegaly estimates 7.6 (95% CI: 5.7 - 10.1), and for the mitotic count 30.5 (95% CI: 7.8 - 118.0). Inter-rater reproducibility for karyomegaly estimates was fair ($\kappa$ = 0.226) with highly variable sensitivity/specificity values for the individual pathologists. Reproducibility for manual morphometry (SD of nuclear area) was good (ICC = 0.654). This study supports the use of algorithmic morphometry as a prognostic test to overcome the limitations of estimates and manual measurements

Das Massaker im ehemaligen „Zuchthaus“ Stein und die „Kremser Hasenjagd“ im gegenwärtigen lokalen Gedächtnis

Das Massaker im ehemaligen „Zuchthaus“ Stein und die „Kremser Hasenjagd“ im April 1945 gehören zu den größten Endphaseverbrechen auf dem Gebiet des heutigen Österreichs. Die Arbeit untersucht deren Platz im gegenwärtigen lokalen Gedächtnis. Im ersten Teil werden die Ereignisse in ihrem historischer Kontext, ihre gerichtliche Aufarbeitung und die vergangenen und aktuellen Formen des Gedenkens mittels Literaturrecherche dargestellt. Im zweiten Teil werden mittels einer Online-Befragung (Standardisierter quantitativer Fragebogen) mit dem Befragungstool Questback Einstellungen zum Gedenken an diese NS-Verbrechen bei lokalen GeschichtelehrerInnen, GemeinderätInnen und AktivistInnen erhoben und analysiert. Nach einem jahrzehntelangem „Schweigegebot“ wurden die Ereignisse erst Mitte der 1990er Jahre wieder öffentlich thematisiert – fast ausschließlich von Privatpersonen und zivilgesellschaftlichen Initiativen. Das Massaker im ehemaligen „Zuchthaus“ Stein scheint durch die Fokussierung des Gedenkens und das offizielle Gedenken der Stadt Krems im lokalen kulturellen Gedächtnis etabliert. Die Verbrechen der „Kremser Hasenjagd“ werden hingegen kaum öffentlich thematisiert und entschwinden zunehmend aus dem kommunikativen Gedächtnis (Ausnahme: Hadersdorf am Kamp). Die Verbrechen sind nach Einschätzung der TeilnehmerInnen an der Befragung heute lokal nur mehr wenig/mittelmäßig bekannt und es gibt wenig Interesse an einer Auseinandersetzung in der lokalen Bevölkerung. Aufgrund des jahrzehntelangen „Schweigegebots“ bestehen weiterhin lokale Mythen innerhalb der lokalen Bevölkerung. Die Einstellungen zum Gedenken sind in allen Untersuchungsgruppen sehr positiv. Eine deutliche Mehrheit ist für eine umfangreiche Aufarbeitung der „Kremser Hasenjagd“ und dafür, den Hinweisen auf vermutete Massengräber nachzugehen. Mehrheitlich wird für eine Umbettung der Toten plädiert. Das offizielle Gedenken der Stadt Krems wird als wichtig und vorbildhaft gesehen; die Aufgabe des Gedenkens Gemeinden und Schulen zugeschrieben

Who Is Doing the Job? Unraveling the Role of Ga₂O₃ in Methanol Steam Reforming on Pd₂Ga/Ga₂O₃

A systematic study of the nature, stability, and dynamics of surface species present under methanol steam reforming (MSR) conditions over Pd/Ga₂O₃ and Pd₂Ga/Ga₂O₃ was performed by combining steady state and concentration modulation FTIR spectroscopy. This powerful combination allowed us to obtain novel mechanistic insights into the selective pathway leading to the formation of H₂ and CO₂ and thus to contribute to the understanding of the remarkably different catalytic properties of Pd/Ga₂O₃ and Pd₂Ga/Ga₂O₃. Strongly enhanced formation of adsorbed formates at low temperatures was detected on Pd₂Ga/Ga₂O₃. We ascribe the facilitated formation of these species to the presence of reactive oxygen sites in the Ga₂O₃ surface, which are formed during high-temperature reduction and formation of the intermetallic compound Pd₂Ga. While the stability of involved formates is high under reaction conditions of methanol decomposition (i.e., in the absence of H₂O), the entire adsorption system behaves more dynamically in the presence of water. We propose that the introduction of H₂O into the system converts stable bridging- and bidentate formates into more reactive, monodentate species. These react either with adsorbed methoxy to methyl formate (MFO) in the absence of water or with OH groups supplied by H₂O to CO₂ and H₂. The reaction with OH is faster, leading to a smaller concentration of intermediate monodentate formate under MSR conditions. MFO is easily decomposed into CO and CH₃OH and therefore, it is unlikely to be an intermediate in the selective MSR reaction to CO₂ and H₂. While the formation of intermetallic particles by high-temperature reduction is a prerequisite to achieving high MSR selectivity, our results suggest that the reaction sequence predominantly proceeds on the Ga₂O₃ surface, that is modified by the high temperature reduction and the formation of Pd₂Ga, and is only promoted by the presence of the intermetallic particles

In situ study of the formation and stability of supported Pd2Ga methanol steam reforming catalysts

Pd/Ga2O3 methanol steam reforming (MSR) catalysts were characterized in detail by utilizing a range of in situ techniques of varying surface sensitivity. Correlating the nature of the intermetallic Pd-Ga compound (IMC; formed upon reduction) with the corresponding activity/selectivity revealed pronounced differences. Generally, a dynamic response of the catalyst surface to the surrounding gas environment was observed. Special attention was paid to the bulk and surface stability of the Pd-Ga IMCs. Whereas the bulk was stable in O2, decomposition of the surface occurred resulting in a partial coverage by GaxOy islands. In addition, we focused on the formation mechanism of undesired CO and were able to identify the reasons limiting the selectivity to MSR. We observed a detrimental effect of CO on the selective Pd-Ga intermetallic compound, causing partial decomposition of the IMC to metallic Pd at the surface. Consequently, patches of Pd metal are present under reaction conditions, catalyzing the unwanted parallel methanol decocomposition reaction

Microstructural Changes of Supported Intermetallic Nanoparticles under Reductive and Oxidative Conditions: An in Situ X‑ray Absorption Study of Pd/Ga₂O₃

In this work, the structure and stability of Pd–Ga intermetallic nanoparticles under various reactive conditions was investigated by combining in situ X-ray absorption spectroscopy (XAS), FTIR of CO adsorption, and XRD. By in situ XAS we followed in detail the formation of Pd–Ga intermetallic compounds (IMC) upon reduction of Pd/Ga₂O₃, which was observed to be a rather slow process that depends on the availability of reduced Ga formed by the atomic H provided by Pd. Using crystal structures of a variety of Pd–Ga IMCs, we have identified Pd₂Ga as the compound that is formed during reduction at 623 K. In contrast to Pd/Ga₂O₃, β-hydride formation did not occur once Pd₂Ga particles are formed, as evidenced by the absence of lattice expansion in hydrogen atmosphere. However, XAS revealed that Pd₂Ga is not stable in oxygen already at room temperature. Although XRD showed no bulk structural modification, CO adsorption on an oxygen exposed catalyst detected a metallic Pd surface, partly decorated with oxidic Ga. Only in situ XAS provided clear indications on the structural modification occurring upon oxygen exposure, showing that the overall state of the sample is a mixture of Pd or a Ga-depleted IMC and Pd₂Ga. Based on these observations, Ga segregation from the surface-near region to the surface, followed by oxidation, was concluded. The intermetallic surface is easily reformed by reduction, due to remaining Pd at the surface activating H₂