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Yersinia pestis, the pathogen causing plague, requires iron to grow. Y. pestis employs several uptake pathways for iron, including the siderophore yersiniabactin, as well as hemin and inorganic iron. The Y. pestis iron assimilation repertoire further harbors the uncharacterized YiuRABC pathway, presumed to transport an as yet unidentified Fe(III)-siderophore(s). Through intrinsic fluorescence quenching of the periplasmic binding protein YiuA, we discovered that YiuA displays high affinity towards Fe(III) complexes of the hydrolysis products of enterobactin, Fe(III)-[di-(DHB-LSer)] and Fe(III)-[DHB-LSer]2, with Kd‘s of 27.6 ± 4.2 nM and 28.2 ± 6.9 nM, respectively, as well as the bis-catechol siderophore butanochelin, with Kd 0.76 ± 0.17 nM. By comparison, YiuA has a much weaker affinity for intact Fe(III)-enterobactin, Kd 444.7 ± 20.6 nM. Electronic circular dichroism spectroscopy reveals YiuA has a strong preference for binding Λ configured Fe(III)-siderophores, which can be achieved with the Fe(III) bis-catechol complexes but not Fe(III)-enterobactin. 

Abstract PurposeSpecialized robotic and surgical tools are increasing the complexity of operating rooms (ORs), requiring elaborate preparation especially when techniques or devices are to be used for the first time. Spatial planning can improve efficiency and identify procedural obstacles ahead of time, but real ORs offer little availability to optimize space utilization. Methods for creating reconstructions of physical setups, i.e., digital twins, are needed to enable immersive spatial planning of such complex environments in virtual reality. MethodsWe present a neural rendering-based method to create immersive digital twins of complex medical environments and devices from casual video capture that enables spatial planning of surgical scenarios. To evaluate our approach we recreate two operating rooms and ten objects through neural reconstruction, then conduct a user study with 21 graduate students carrying out planning tasks in the resulting virtual environment. We analyze task load, presence, perceived utility, plus exploration and interaction behavior compared to low visual complexity versions of the same environments. ResultsResults show significantly increased perceived utility and presence using the neural reconstruction-based environments, combined with higher perceived workload and exploratory behavior. There’s no significant difference in interactivity. ConclusionWe explore the feasibility of using modern reconstruction techniques to create digital twins of complex medical environments and objects. Without requiring expert knowledge or specialized hardware, users can create, explore and interact with objects in virtual environments. Results indicate benefits like high perceived utility while being technically approachable, which may indicate promise of this approach for spatial planning and beyond. 

The current paper addresses two methodological problems pertinent to the analysis of observer studies in nonverbal rapport and beyond. These problems concern: (1) the production of standardized stimulus materials that allow for unbiased observer ratings and (2) the objective measurement of nonverbal behaviors to identify the dyadic patterns underlying the observer impressions. We suggest motion capture and character animation as possible solutions to these problems and exemplarily apply the novel methodology to the study of gender and cultural differences in nonverbal rapport. We compared a Western, individualistic culture with an egalitarian gender-role conception (Germany) and a collectivistic culture with a more traditional gender role conceptions (Middle East, Gulf States). Motion capture data were collected for five male and five female dyadic interactions in each culture. Character animations based on the motion capture data served as stimuli in the observation study. Female and male observers from both cultures rated the perceived rapport continuously while watching the 1 min sequences and guessed gender and cultural background of the dyads after each clip. Results show that masking of gender and culture in the stimuli was successful, as hit rates for both aspects remained at chance level. Further the results revealed high levels of agreement in the rapport ratings across gender and culture, pointing to universal judgment policies. A 2 × 2 × 2 × 2 ANOVA for gender and culture of stimuli and observers showed that female dyads were rated significantly higher on rapport across the board and that the contrast between female and male dyads was more pronounced in the Arab sample as compared to the German sample. nonverbal parameters extracted from the motion capture protocols were submitted to a series of algorithms to identify dyadic activity levels and coordination patterns relevant to the perception of rapport. The results are critically discussed with regard to the role of nonverbal coordination as a constituent of rapport.