2001: Annual Disease Nursery Report

unpublishednot peer reviewe

Vector-field statistics for the analysis of time varying clinical gait data.

BACKGROUND: In clinical settings, the time varying analysis of gait data relies heavily on the experience of the individual(s) assessing these biological signals. Though three dimensional kinematics are recognised as time varying waveforms (1D), exploratory statistical analysis of these data are commonly carried out with multiple discrete or 0D dependent variables. In the absence of an a priori 0D hypothesis, clinicians are at risk of making type I and II errors in their analyis of time varying gait signatures in the event statistics are used in concert with prefered subjective clinical assesment methods. The aim of this communication was to determine if vector field waveform statistics were capable of providing quantitative corroboration to practically significant differences in time varying gait signatures as determined by two clinically trained gait experts. METHODS: The case study was a left hemiplegic Cerebral Palsy (GMFCS I) gait patient following a botulinum toxin (BoNT-A) injection to their left gastrocnemius muscle. FINDINGS: When comparing subjective clinical gait assessments between two testers, they were in agreement with each other for 61% of the joint degrees of freedom and phases of motion analysed. For tester 1 and tester 2, they were in agreement with the vector-field analysis for 78% and 53% of the kinematic variables analysed. When the subjective analyses of tester 1 and tester 2 were pooled together and then compared to the vector-field analysis, they were in agreement for 83% of the time varying kinematic variables analysed. INTERPRETATION: These outcomes demonstrate that in principle, vector-field statistics corroborates with what a team of clinical gait experts would classify as practically meaningful pre- versus post time varying kinematic differences. The potential for vector-field statistics to be used as a useful clinical tool for the objective analysis of time varying clinical gait data is established. Future research is recommended to assess the usefulness of vector-field analyses during the clinical decision making process

Polyimide/SU-8 catheter-tip MEMS gauge pressure sensor.

This paper describes the development of a polyimide/SU-8 catheter-tip MEMS gauge pressure sensor. Finite element analysis was used to investigate critical parameters, impacting on the device design and sensing characteristics. The sensing element of the device was fabricated by polyimide-based micromachining on a flexible membrane, using embedded thin-film metallic wires as piezoresistive elements. A chamber containing this flexible membrane was sealed using an adapted SU-8 bonding technique. The device was evaluated experimentally and its overall performance compared with a commercial silicon-based pressure sensor. Furthermore, the device use was demonstrated by measuring blood pressure and heart rate in vivo

Smut Gall Development in Adult Corn Plants Inoculated with Ustilago maydis

Tassel galls were induced in 100% of corn plants in which the leaf whorl was injected with a suspension of sporidia of compatible isolates of Ustilago maydis 3–10 days before tassel emergence. Ear galls were induced at high frequency in Tastyvee sweet corn plants in which the sporidial suspension was injected between the leaf sheath and stalk at the sixth, seventh, and eighth nodes below the top of the plant 0–8 days before tassel emergence. Gall development was more variable in stalks and axillary buds than in ears. Mean incubation periods for appearance of galls in sweet corn hybrids grown in pots, greenhouse soil beds, and field plots were 17.5, 16, and 19 days, respectively. Ear galls were much larger on plants inoculated in the field than on those inoculated in the greenhouse, but the size of galls on stalks or axillary buds did not differ significantly for greenhouse- and field-grown plants. Inoculated hybrids in soil beds in the greenhouse had 27–77% fewer ears than the same hybrids left untreated or injected with water; 25% of those with galls on primary or secondary ears produced at least one normal ear, 23% of those without ear galls but with galls on stalks or axillary buds produced ears, and 32% of those with galls only on leaves or tassels produced ears. The injection technique is suitable for studies of host-pathogen interactions between corn and U. maydis in which typical gall development for adult plants is essential, but it may require some refinement before it can be used to screen corn genotypes for quantitative resistance to common smut

The evolution of compliance in the human lateral mid-foot.

Fossil evidence for longitudinal arches in the foot is frequently used to constrain the origins of terrestrial bipedality in human ancestors. This approach rests on the prevailing concept that human feet are unique in functioning with a relatively stiff lateral mid-foot, lacking the significant flexion and high plantar pressures present in non-human apes. This paradigm has stood for more than 70 years but has yet to be tested objectively with quantitative data. Herein, we show that plantar pressure records with elevated lateral mid-foot pressures occur frequently in healthy, habitually shod humans, with magnitudes in some individuals approaching absolute maxima across the foot. Furthermore, the same astonishing pressure range is present in bonobos and the orangutan (the most arboreal great ape), yielding overlap with human pressures. Thus, while the mean tendency of habitual mechanics of the mid-foot in healthy humans is indeed consistent with the traditional concept of the lateral mid-foot as a relatively rigid or stabilized structure, it is clear that lateral arch stabilization in humans is not obligate and is often transient. These findings suggest a level of detachment between foot stiffness during gait and osteological structure, hence fossilized bone morphology by itself may only provide a crude indication of mid-foot function in extinct hominins. Evidence for thick plantar tissues in Ardipithecus ramidus suggests that a human-like combination of active and passive modulation of foot compliance by soft tissues extends back into an arboreal context, supporting an arboreal origin of hominin bipedalism in compressive orthogrady. We propose that the musculoskeletal conformation of the modern human mid-foot evolved under selection for a functionally tuneable, rather than obligatory stiff structure

NMR spectroscopy and perfusion of mammalian cells using surface microprobes

NMR spectra of mammalian cells are taken using surface microprobes that are based on microfabricated planar coils. The surface microprobe resembles a miniaturized Petri dish commonly used in biological research. The diameter of the planar coils is 1 mm. Chinese Hamster Ovaries are immobilized in a uniform layer on the microprobe surface or patterned by an ink-jet printer in the centre of the microcoil, where the rf-field of the planar microcoil is most uniform. The acquired NMR spectra show the prevalent metabolites found in mammalian cells. The volumes of the detected samples range from 25 nL to 1 nL (or 50000 to 1800 cells). With an extended set-up that provides fluid inlets and outlets to the microprobe, the cells can be perfused within the NMR-magnet while constantly taking NMR spectra. Perfusion of the cells opens the way to increased cell viability for long acquisitions or to analysis of the cells response to environmental change

Phenology of brown bear breeding season and related geographical cues

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited[EN] Knowledge about breeding biology is often incomplete in species with complex reproductive strategies. The brown bear Ursus arctos is a polygamous seasonal breeder inhabiting a wide variety of habitats and environmental conditions. We compiled information about brown bear breeding season dates from 36 study areas across their distribution range in the Palearctic and Nearctic regions and investigated how their breeding phenology relates to geographical factors (latitude, photoperiod, altitude and region). Brown bear matings were observed for 8 months, from April to November, with a peak in May–July. We found a 59-day difference in the onset of bear breeding season among study areas, with an average 2.3 days delay for each degree of latitude northwards. The onset of the breeding season showed a strong relationship with photoperiod and latitude, but not with region (i.e. Palearctic vs Nearctic) and altitude. First observations of bear mating occurred earlier in areas at lower latitudes. Photoperiod ranged between 14 and 18 hours at the beginning of the season for most of the study areas. The duration of the breeding season ranged from 25 to 138 days among study areas. None of the investigated factors was related to the length of the breeding season. Our results support the relevance of photoperiod to the onset of breeding, as found in other ursids, but not a shorter breeding season at higher latitudes, a pattern reported in other mammals. Our findings suggest a marked seasonality of bear reproductive behaviour, but also certain level of plasticity. Systematic field observations of breeding behaviour are needed to increase our knowledge on the factors determining mating behaviour in species with complex systems and how these species may adapt to climate change.SIWe thank Marjan Artnak, Peter Bajc, Matic Brenk, Tomáš Flajs, Uroš Grželj, Robert Hlavica, Aleš Jagodnik, Peter Klančar, Anton Marinčič, Mariusz Nędzyński, Borut Semenič and Vladimir Vician for providing information about their observations of bear mating. Robert Gatzka assisted with data collection in the Biezszcady Mountains. We thank Jon Swenson and Jumpei Tomiyasu for their help in the literature search. AGR and NS were supported by the BearConnect project funded by the National Science Centre in Poland (2016/22/Z/NZ8/00121) through the 2015-2016 BiodivERsA COFUND call for research proposals, with the national funders ANR/DLR-PT/UEFISCDI/NCN/RCN. Additional funding from the Polish Ministry of Science and Higher Education (project NN304- 294037, NS, IEC, KB), the National Science Centre in Poland (project DEC-2013/08/M/NZ9/ 00469, NS), the National Centre for Research and Development (GLOBE, POL-NOR/198352/85/ 2013, NS, TZK, FZ) and Slovenian Research Agency (P4-0059, MK) is acknowledged. AGR and NS conceived the study and wrote a first draft of the paper; AGR and NS compiled the data, AGR analyzed the data; all authors provided data and comments that improved the manuscript. We thank two anonymous reviewers for useful comments on the previous versions of the manuscript

Simulation modeling for stratified breast cancer screening : a systematic review of cost and quality of life assumptions

BACKGROUND: The economic evaluation of stratified breast cancer screening gains momentum, but produces also very diverse results. Systematic reviews so far focused on modeling techniques and epidemiologic assumptions. However, cost and utility parameters received only little attention. This systematic review assesses simulation models for stratified breast cancer screening based on their cost and utility parameters in each phase of breast cancer screening and care. METHODS: A literature review was conducted to compare economic evaluations with simulation models of personalized breast cancer screening. Study quality was assessed using reporting guidelines. Cost and utility inputs were extracted, standardized and structured using a care delivery framework. Studies were then clustered according to their study aim and parameters were compared within the clusters. RESULTS: Eighteen studies were identified within three study clusters. Reporting quality was very diverse in all three clusters. Only two studies in cluster 1, four studies in cluster 2 and one study in cluster 3 scored high in the quality appraisal. In addition to the quality appraisal, this review assessed if the simulation models were consistent in integrating all relevant phases of care, if utility parameters were consistent and methodological sound and if cost were compatible and consistent in the actual parameters used for screening, diagnostic work up and treatment. Of 18 studies, only three studies did not show signs of potential bias. CONCLUSION: This systematic review shows that a closer look into the cost and utility parameter can help to identify potential bias. Future simulation models should focus on integrating all relevant phases of care, using methodologically sound utility parameters and avoiding inconsistent cost parameters