Pick-N multiple choice-exams: a comparison of scoring algorithms

To compare different scoring algorithms for Pick-N multiple correct answer multiple-choice (MC) exams regarding test reliability, student performance, total item discrimination and item difficulty. Data from six 3rd year medical students' end of term exams in internal medicine from 2005 to 2008 at Munich University were analysed (1,255 students, 180 Pick-N items in total). Scoring Algorithms: Each question scored a maximum of one point. We compared: (a) Dichotomous scoring (DS): One point if all true and no wrong answers were chosen. (b) Partial credit algorithm 1 (PS(50)): One point for 100% true answers; 0.5 points for 50% or more true answers; zero points for less than 50% true answers. No point deduction for wrong choices. (c) Partial credit algorithm 2 (PS(1/m)): A fraction of one point depending on the total number of true answers was given for each correct answer identified. No point deduction for wrong choices. Application of partial crediting resulted in psychometric results superior to dichotomous scoring (DS). Algorithms examined resulted in similar psychometric data with PS(50) only slightly exceeding PS(1/m) in higher coefficients of reliability. The Pick-N MC format and its scoring using the PS(50) and PS(1/m) algorithms are suited for undergraduate medical examinations. Partial knowledge should be awarded in Pick-N MC exams

Soft-Collinear Messengers: A New Mode in Soft-Collinear Effective Theory

It is argued that soft-collinear effective theory for processes involving both soft and collinear partons, such as exclusive B-meson decays, should include a new mode in addition to soft and collinear fields. These "soft-collinear messengers" can interact with both soft and collinear particles without taking them far off-shell. They thus can communicate between the soft and collinear sectors of the theory. The relevance of the new mode is demonstrated with an explicit example, and the formalism incorporating the corresponding quark and gluon fields into the effective Lagrangian is developed.Comment: 22 pages, 5 figures. Extended Section 6, clarifying the relevance of different types of soft-collinear interaction

Icolos: a workflow manager for structure-based post-processing of de novo generated small molecules

A Summary: We present Icolos, a workflow manager written in Python as a tool for automating complex structure-based workflows for drug design. Icolos can be used as a standalone tool, for example in virtual screening campaigns, or can be used in conjunction with deep learning-based molecular generation facilitated for example by REINVENT, a previously published molecular de novo design package. In this publication, we focus on the internal structure and general capabilities of Icolos, using molecular docking experiments as an illustrative example

Concept mapping for supporting the differential diagnostic generation of hypotheses in the case-based online learning system CASUS: Qualitative improvement of dagnostic performance through ICD-10 coding

Einleitung: Der Einsatz von Concept-Mapping-Tools in computergestützten Lernprogrammen ist in der medizinischen Ausbildung etabliert: Es konnte gezeigt werden, dass diese Werkzeuge zur Visualisierung von Differentialdiagnosen vom Anwender akzeptiert werden und zu einer vermehrten Hypothesenbildung beitragen. Es gibt bisher jedoch wenige Erkenntnisse über die Qualität der dabei vom Anwender erstellten Hypothesen. Die vorliegende Studie untersucht die Qualität der im Netzwerk-Tool im fallbasierten Lernsystem CASUS erstellten Hypothesen und inwieweit diese durch Kodierung mittels ICD10 präzisiert werden können. Methodik: Die Lernenden bearbeiteten zu zweit einen Computerlernfall zum Thema Malaria. Wir randomisierten 192 Teilnehmer der Studie aus dem 3. Studienjahr an der Universität München in zwei Gruppen: Gruppe A wurde gebeten, die erdachten Hypothesen vor der Eingabe in das Netzwerk-Tool mittels eines ICD10-Browsers zu kodieren. Gruppe B erstellte ihre Hypothesen ohne weitere Hilfsmittel. Die Netzwerke wurden quantitativ und qualitativ evaluiert und die Ergebnisse der beiden Gruppen verglichen. Als Referenz diente das von Experten erstellte Netzwerk. Ergebnisse: 87 differentialdiagnostische Netzwerke konnten ausgewertet werden. In Gruppe A mit ICD10-Kodierung der Hypothesen, konnten die Lernenden signifikant häufiger (p<0,005) die exakte Hauptdiagnose Malaria tropica stellen. In der Gruppe ohne ICD10 Kodierung wurde signifikant häufiger (p<0,005) die unpräzise Diagnose "Malaria" gestellt. Für die Nebendiagnosen ergaben sich qualitativ und quantitativ keine Unterschiede. Schlussfolgerungen: Die ICD10-Kodierung der Hypothesen im Netzwerk-Tool führte zu einer präziseren Diagnosestellung der Studierenden im klinischen Studienabschnitt. Die Integration eines ICD-Browsers zur Unterstützung der differentialdiagnostischen Hypothesenbildung in fallbasierten Lernsystemen ist sinnvoll.Introduction: Concept mapping tools have long been established in medical education as an aid for visualizing learning processes in computer-based programs. The case-based learning system CASUS with its mapping tool for visualizing the differential diagnostic reasoning process is an example. It was shown that such tools are well accepted by users and lead to an increased number of diagnostic hypotheses being visualized as maps. However, there is scarce evidence on the quality of user-generated diagnostic hypotheses. This study examines the quality of diagnostic hypotheses obtained with CASUS and whether the quality can be improved through ICD-10 coding as compared with an expert’s solution. Methods: We randomized 192 third-year medical students at the University of Munich into two groups. The students worked in groups of two on one computer. Group A was asked to code their diagnostic hypotheses with an ICD-10 coding browser before entering them into the mapping tool. Group B generated their hypotheses without prior ICD-10 coding. The differential diagnostic reasoning visualizations were analyzed quantitatively and qualitatively. An expert solution was used as reference. Results: Eighty-seven differential diagnoses were evaluated. Group A, using ICD-10 coding, made the correct and precise diagnosis of malaria tropica significantly more often than Group B (p < 0.05). For additional alternative diagnostic hypotheses, no quantitative or qualitative differences were detected. Conclusions: ICD-10 coding in connection with a mapping tool supporting the diagnostic reasoning process improved the accuracy of diagnostic performance in third-year medical students in the case of malaria tropica

Exploiting transient protein states for the design of small-molecule stabilizers of mutant p53

The destabilizing p53 cancer mutation Y220C creates an extended crevice on the surface of the protein that can be targeted by small-molecule stabilizers. Here, we identify different classes of small molecules that bind to this crevice and determine their binding modes by X-ray crystallography. These structures reveal two major conformational states of the pocket and a cryptic, transiently open hydrophobic subpocket that is modulated by Cys220. In one instance, specifically targeting this transient protein state by a pyrrole moiety resulted in a 40-fold increase in binding affinity. Molecular dynamics simulations showed that both open and closed states of this subsite were populated at comparable frequencies along the trajectories. Our data extend the framework for the design of high-affinity Y220C mutant binders for use in personalized anticancer therapy and, more generally, highlight the importance of implementing protein dynamics and hydration patterns in the drug-discovery process

Electrochemical Reduction and Oxidation of Ruddlesden–Popper-Type La2_{2}NiO3_{3}F2_{2} within Fluoride-Ion Batteries

Within this article, it is shown that an electrochemical defluorination and additional fluorination of Ruddlesden–Popper-type La$_2$NiO$_3$F$_2$ is possible within all-solid-state fluoride-ion batteries. Structural changes within the reduced and oxidized phases have been examined by X-ray diffraction studies at different states of charging and discharging. The synthesis of the oxidized phase La$_2$NiO$_3$F$_{2+x}$ proved to be successful by structural analysis using both X-ray powder diffraction and automated electron diffraction tomography techniques. The structural reversibility on re-fluorinating and re-defluorinating is also demonstrated. Moreover, the influence of different sequences of consecutive reduction and oxidation steps on the formed phases has been investigated. The observed structural changes have been compared to changes in phases obtained via other topochemical modification approaches such as hydride-based reduction and oxidative fluorination using F$_2$ gas, highlighting the potential of such electrochemical reactions as alternative synthesis routes. Furthermore, the electrochemical routes represent safe and controllable synthesis approaches for novel phases, which cannot be synthesized via other topochemical methods. Additionally, side reactions, occurring alongside the desired electrochemical reactions, have been addressed and the cycling performance has been studied

Transcriptional profiling reveals barcode-like toxicogenomic responses in the zebrafish embryo

Microarray profiling of zebrafish embryos exposed to a range of environmental toxicants revealed distinct expression profiles for each of the toxicants tested

Electroweak Gauge-Boson Production at Small q_T: Infrared Safety from the Collinear Anomaly

Using methods from effective field theory, we develop a novel, systematic framework for the calculation of the cross sections for electroweak gauge-boson production at small and very small transverse momentum q_T, in which large logarithms of the scale ratio M_V/q_T are resummed to all orders. These cross sections receive logarithmically enhanced corrections from two sources: the running of the hard matching coefficient and the collinear factorization anomaly. The anomaly leads to the dynamical generation of a non-perturbative scale q_* ~ M_V e^{-const/\alpha_s(M_V)}, which protects the processes from receiving large long-distance hadronic contributions. Expanding the cross sections in either \alpha_s or q_T generates strongly divergent series, which must be resummed. As a by-product, we obtain an explicit non-perturbative expression for the intercept of the cross sections at q_T=0, including the normalization and first-order \alpha_s(q_*) correction. We perform a detailed numerical comparison of our predictions with the available data on the transverse-momentum distribution in Z-boson production at the Tevatron and LHC.Comment: 34 pages, 9 figure