Xplainer: From X-Ray Observations to Explainable Zero-Shot Diagnosis

Automated diagnosis prediction from medical images is a valuable resource to support clinical decision-making. However, such systems usually need to be trained on large amounts of annotated data, which often is scarce in the medical domain. Zero-shot methods address this challenge by allowing a flexible adaption to new settings with different clinical findings without relying on labeled data. Further, to integrate automated diagnosis in the clinical workflow, methods should be transparent and explainable, increasing medical professionals' trust and facilitating correctness verification. In this work, we introduce Xplainer, a novel framework for explainable zero-shot diagnosis in the clinical setting. Xplainer adapts the classification-by-description approach of contrastive vision-language models to the multi-label medical diagnosis task. Specifically, instead of directly predicting a diagnosis, we prompt the model to classify the existence of descriptive observations, which a radiologist would look for on an X-Ray scan, and use the descriptor probabilities to estimate the likelihood of a diagnosis. Our model is explainable by design, as the final diagnosis prediction is directly based on the prediction of the underlying descriptors. We evaluate Xplainer on two chest X-ray datasets, CheXpert and ChestX-ray14, and demonstrate its effectiveness in improving the performance and explainability of zero-shot diagnosis. Our results suggest that Xplainer provides a more detailed understanding of the decision-making process and can be a valuable tool for clinical diagnosis.Comment: 9 pages, 2 figures, 6 table

Annihilation emission from young supernova remnants

A promising source of the positrons that contribute through annihilation to the diffuse Galactic 511keV emission is the beta-decay of unstable nuclei like 56Ni and 44Ti synthesised by massive stars and supernovae. Although a large fraction of these positrons annihilate in the ejecta of SNe/SNRs, no point-source of annihilation radiation appears in the INTEGRAL/SPI map of the 511keV emission. We exploit the absence of detectable annihilation emission from young local SNe/SNRs to derive constraints on the transport of MeV positrons inside SN/SNR ejecta and their escape into the CSM/ISM, both aspects being crucial to the understanding of the observed Galactic 511keV emission. We simulated 511keV lightcurves resulting from the annihilation of the decay positrons of 56Ni and 44Ti in SNe/SNRs and their surroundings using a simple model. We computed specific 511keV lightcurves for Cas A, Tycho, Kepler, SN1006, G1.9+0.3 and SN1987A, and compared these to the upper-limits derived from INTEGRAL/SPI observations. The predicted 511keV signals from positrons annihilating in the ejecta are below the sensitivity of the SPI instrument by several orders of magnitude, but the predicted 511keV signals for positrons escaping the ejecta and annihilating in the surrounding medium allowed to derive upper-limits on the positron escape fraction of ~13% for Cas A, ~12% for Tycho, ~30% for Kepler and ~33% for SN1006. The transport of ~MeV positrons inside SNe/SNRs cannot be constrained from current observations of the 511keV emission from these objects, but the limits obtained on their escape fraction are consistent with a nucleosynthesis origin of the positrons that give rise to the diffuse Galactic 511keV emission.Comment: 15 pages, 11 figures, accepted for publication in A&

Double-strand break repair and colorectal cancer: gene variants within 3' UTRs and microRNAs binding as modulators of cancer risk and clinical outcome

Genetic variations in 3' untranslated regions of target genes may affect microRNA binding, resulting in differential protein expression. microRNAs regulate DNA repair, and single-nucleotide polymorphisms in miRNA binding sites (miRSNPs) may account for interindividual differences in the DNA repair capacity. Our hypothesis is that miRSNPs in relevant DNA repair genes may ultimately affect cancer susceptibility and impact prognosis.In the present study, we analysed the association of polymorphisms in predicted microRNA target sites of double-strand breaks (DSBs) repair genes with colorectal cancer (CRC) risk and clinical outcome. Twenty-one miRSNPs in non-homologous end-joining and homologous recombination pathways were assessed in 1111 cases and 1469 controls. The variant CC genotype of rs2155209 in MRE11A was strongly associated with decreased cancer risk when compared with the other genotypes (OR 0.54, 95% CI 0.38-0.76, p = 0.0004). A reduced expression of the reporter gene was observed for the C allele of this polymorphism by in vitro assay, suggesting a more efficient interaction with potentially binding miRNAs. In colon cancer patients, the rs2155209 CC genotype was associated with shorter survival while the TT genotype of RAD52 rs11226 with longer survival when both compared with their respective more frequent genotypes (HR 1.63, 95% CI 1.06-2.51, p = 0.03 HR 0.60, 95% CI 0.41-0.89, p = 0.01, respectively). miRSNPs in DSB repair genes involved in the maintenance of genomic stability may have a role on CRC susceptibility and clinical outcome

Effects of solute and vacancy segregation on antiphase boundary migration in stoichiometric and Al-rich Fe₃Al: a phase-field simulation study

Effects of segregation of solute atoms and vacancies on migration of antiphase boundaries (APBs) in stoichiometric (Fe-25 at%Al) and Al-rich (Fe-28 at%Al) Fe₃Al at 673 K have been studied using a phase-field method in which local vacancy concentration is taken into account [Koizumi Y, Allen SM, Minamino Y. Acta Mater 2008;56:5861, ibid. 2009;57:3039]. Boundary mobility (M) of APBs having different phase-shift vectors of a/4 and a/2 (hereafter denoted as B2-APB and D0₃-APB, respectively) was evaluated by measuring the boundary velocity of shrinking circular APBs. Similar effects of the segregation on the migration of B2-APBs were observed in both compositions. Vacancies segregated and Al-atoms were depleted at B2-APBs in both compositions. Vacancy concentration at B2-APBs was up to 80% higher than that in the bulk. As a result, the migration of B2-APBs was greatly enhanced by the vacancy segregation. In contrast, the segregation to D0₃-APBs showed a marked composition dependence. Vacancies were depleted and Al-atoms segregated at D0₃-APBs in the Al-rich Fe₃Al, whereas vacancies segregated and Al-atoms were depleted at D0₃-APB in the stoichiometric Fe₃Al. The Al segregation in the Al-rich Fe3Al decreased M of D0₃-APBs much more significantly than the Al-depletion in the stoichiometric Fe₃Al. As the APDs shrank, D0₃-APBs broke away from the segregation atmospheres and the M increased rapidly in both compositions. A greater increase in the M due to the breakaway was observed in the Al-rich Fe₃Al than in Fe₃Al with the stoichiometric composition.Iketani Science and Technology Promotion Foundatio

Magnetically modified TiO2 powders - microstructure and magnetic properties

AbstractThe anatase (TiO2) particles magnetically modified by iron oxides and prepared by an innovating technological procedure are studied from the viewpoint of microstructure and a complex analysis of magnetic behaviour at room and elevated temperatures. Scanning electron microscopy observations have yielded variable shapes of particles in the composite powder whereas the iron oxide particles of diameter bellow 1μm were detected on the surface of the TiO2. The dominant magnetite (Fe3O4) accompanied by a small amount of maghemite (γ-Fe2O3) and/or hematite (α- Fe2O3) were analysed by X-ray powder diffraction. A relatively high saturation magnetization (3.38 Am2/kg), negative dipolar interactions, and the low values of reversible and irreversible part of magnetic susceptibility were found out from magnetic measurements at room temperature. During a thermomagnetic treatment the composite sample has been going through a few magnetic phase transitions and transforms into a fully paramagnetic state around 850K. After its cooling to the room temperature an undesirable magnetic hardening of the sample has occurred

Understanding the socio-economic causes of deforestation: a global perspective

IntroductionThis paper investigates the links between deforestation and key economic, social, environmental, and geographical variables. We focus on per capita GDP, total forest cover, and the population across a diverse sample of countries from five continents for the last three decades.MethodsThis study utilizes a regression model using panel data to show the impact of key economic, and social variables on deforestation. Also, set of dummy variables is introduced in the paper. To enable the investigation, we use a set of dummies to capture their influence. The random effect specifications are used in this investigation. The research focuses on a period ranging from 1990 to 2020.ResultsResults show how different socio-economic variables influence deforestation. For example, disruptive events like the COVID-19 pandemic and the financial crisis had a negative effect on forest area development across all models. GDP per capita has different impact depending on the size of a country. Former colonies seem to have more deforestation.ConclusionsThe global environmental challenges posed by human activities and their impact on the state of forest have become increasingly evident. It is necessary to undertake policy and governance reforms to establish a solid legal framework, strengthen enforcement mechanisms, and foster transparency and accountability. The promotion of sustainable agriculture and agroforestry practices can substantially alleviate pressure on forests. Furthermore, it is necessary to mitigate disruptive events like pandemics by establishing specific strategies and creating contingency plans