223 research outputs found
K-Dominance in Multidimensional Data: Theory and Applications
We study the problem of k-dominance in a set of d-dimensional vectors, prove bounds on the number of maxima (skyline vectors), under both worst-case and average-case models, perform experimental evaluation using synthetic and real-world data, and explore an application of k-dominant skyline for extracting a small set of top-ranked vectors in high dimensions where the full skylines can be unmanageably large
Influence of end-expiratory level and tidal volume on gravitational ventilation distribution during tidal breathing in healthy adults
Our understanding of regional filling of the lung and regional ventilation distribution is based on studies using stepwise inhalation of radiolabelled tracer gases, magnetic resonance imaging and positron emission tomography. We aimed to investigate whether these differences in ventilation distribution at different end-expiratory levels (EELs) and tidal volumes (V Ts) held also true during tidal breathing. Electrical impedance tomography (EIT) measurements were performed in ten healthy adults in the right lateral position. Five different EELs with four different V Ts at each EEL were tested in random order, resulting in 19 combinations. There were no measurements for the combination of the highest EEL/highest V T. EEL and V T were controlled by visual feedback based on airflow. The fraction of ventilation directed to different slices of the lung (VENTRL1âVENTRL8) and the rate of the regional filling of each slice versus the total lung were analysed. With increasing EEL but normal tidal volume, ventilation was preferentially distributed to the dependent lung and the filling of the right and left lung was more homogeneous. With increasing V T and maintained normal EEL (FRC), ventilation was preferentially distributed to the dependent lung and regional filling became more inhomogeneous (p<0.05). We could demonstrate that regional and temporal ventilation distribution during tidal breathing was highly influenced by EEL and V
Measurement of ventilation and cardiac related impedance changes with electrical impedance tomography
Introduction Electrical impedance tomography (EIT) has been shown to be able to distinguish both ventilation and perfusion. With adequate filtering the regional distributions of both ventilation and perfusion and their relationships could be analysed. Several methods of separation have been suggested previously, including breath holding, electrocardiograph (ECG) gating and frequency filtering. Many of these methods require interventions inappropriate in a clinical setting. This study therefore aims to extend a previously reported frequency filtering technique to a spontaneously breathing cohort and assess the regional distributions of ventilation and perfusion and their relationship. Methods Ten healthy adults were measured during a breath hold and while spontaneously breathing in supine, prone, left and right lateral positions. EIT data were analysed with and without filtering at the respiratory and heart rate. Profiles of ventilation, perfusion and ventilation/perfusion related impedance change were generated and regions of ventilation and pulmonary perfusion were identified and compared. Results Analysis of the filtration technique demonstrated its ability to separate the ventilation and cardiac related impedance signals without negative impact. It was, therefore, deemed suitable for use in this spontaneously breathing cohort. Regional distributions of ventilation, perfusion and the combined ÎZV/ÎZQ were calculated along the gravity axis and anatomically in each position. Along the gravity axis, gravity dependence was seen only in the lateral positions in ventilation distribution, with the dependent lung being better ventilated regardless of position. This gravity dependence was not seen in perfusion. When looking anatomically, differences were only apparent in the lateral positions. The lateral position ventilation distributions showed a difference in the left lung, with the right lung maintaining a similar distribution in both lateral positions. This is likely caused by more pronounced anatomical changes in the left lung when changing positions. Conclusions The modified filtration technique was demonstrated to be effective in separating the ventilation and perfusion signals in spontaneously breathing subjects. Gravity dependence was seen only in ventilation distribution in the left lung in lateral positions, suggesting gravity based shifts in anatomical structures. Gravity dependence was not seen in any perfusion distributions
High-resolution isotopic evidence of specialised cattle herding in the European Neolithic.
Peer reviewe
Prone equals prone? Impact of positioning techniques on respiratory function in anesthetized and paralyzed healthy children
Objectives: Although the prone position is effectively used to improve oxygenation, its impact on functional residual capacity is controversial. Different techniques of body positioning might be an important confounding factor. The aim of this study was to determine the impact of two different prone positioning techniques on functional residual capacity and ventilation distribution in anesthetized, preschool-aged children. Design: Functional residual capacity and lung clearance index, ameasure of ventilation homogeneity, were calculated using asulfur-hexafluoride multibreath washout technique. After intubation, measurements were taken in the supine position and, in random order, in the flat prone position and the augmented prone position (gel pads supporting the pelvis and the upper thorax). Setting: Pediatric anesthesia unit of university hospital. Patients and participants: Thirty preschool children without cardiopulmonary disease undergoing elective surgery. Measurements and results: Mean (range) age was 48.5 (24-80) months, weight 17.2 (10.5-26.9)âŻkg, functional residual capacity (mean ±âŻSD) 22.9âŻÂ±âŻ6.2âŻml.kgâ1 in the supine position and 23.3âŻÂ±âŻ5.6âŻml.kgâ1 in the flat prone position, while lung clearance indices were 8.1âŻÂ±âŻ2.3 vs. 7.9âŻÂ±âŻ2.3, respectively. In contrast, functional residual capacity increased to 27.6 ± 6.5 ml.kgâ1 (p<âŻ0.001) in the augmented prone position while at the same time the lung clearance index decreased to 6.7âŻÂ±âŻ0.9 (p<âŻ0.001). Conclusions: Functional residual capacity and ventilation distribution were similar in the supine and flat prone positions, while these parameters improved significantly in the augmented prone position, suggesting that the technique of prone positioning has major implications for pulmonary functio
Onboard Science Instrument Autonomy for the Detection of Microscopy Biosignatures on the Ocean Worlds Life Surveyor
The quest to find extraterrestrial life is a critical scientific endeavor
with civilization-level implications. Icy moons in our solar system are
promising targets for exploration because their liquid oceans make them
potential habitats for microscopic life. However, the lack of a precise
definition of life poses a fundamental challenge to formulating detection
strategies. To increase the chances of unambiguous detection, a suite of
complementary instruments must sample multiple independent biosignatures (e.g.,
composition, motility/behavior, and visible structure). Such an instrument
suite could generate 10,000x more raw data than is possible to transmit from
distant ocean worlds like Enceladus or Europa. To address this bandwidth
limitation, Onboard Science Instrument Autonomy (OSIA) is an emerging
discipline of flight systems capable of evaluating, summarizing, and
prioritizing observational instrument data to maximize science return. We
describe two OSIA implementations developed as part of the Ocean Worlds Life
Surveyor (OWLS) prototype instrument suite at the Jet Propulsion Laboratory.
The first identifies life-like motion in digital holographic microscopy videos,
and the second identifies cellular structure and composition via innate and
dye-induced fluorescence. Flight-like requirements and computational
constraints were used to lower barriers to infusion, similar to those available
on the Mars helicopter, "Ingenuity." We evaluated the OSIA's performance using
simulated and laboratory data and conducted a live field test at the
hypersaline Mono Lake planetary analog site. Our study demonstrates the
potential of OSIA for enabling biosignature detection and provides insights and
lessons learned for future mission concepts aimed at exploring the outer solar
system.Comment: 49 pages, 18 figures, submitted to The Planetary Science Journal on
2023-04-2
E119D Neuraminidase Mutation Conferring Pan-Resistance to Neuraminidase Inhibitors in an A(H1N1)pdm09 Isolate From a Stem-Cell Transplant Recipient
Background.âAn influenza A(H1N1)pdm09 infection was diagnosed in a hematopoietic stem cell transplant recipient during conditioning regimen. He was treated with oral oseltamivir, later combined with intravenous zanamivir. The H275Y neuraminidase (NA) mutation was first detected, and an E119D NA mutation was identified during zanamivir therapy. Methods.âRecombinant wild-type (WT) E119D and E119D/H275Y A(H1N1)pdm09 NA variants were generated by reverse genetics. Susceptibility to NA inhibitors (NAIs) was evaluated with a fluorometric assay using the 2âČ-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (MUNANA) substrate. Susceptibility to favipiravir (T-705) was assessed using plaque reduction assays. The NA affinity and velocity values were determined with NA enzymatic studies. Results.âWe identified an influenza A(H1N1)pdm09 E119D mutant that exhibited a marked increase in the 50% inhibitory concentrations against all tested NAIs (827-, 25-, 286-, and 702-fold for zanamivir, oseltamivir, peramivir, and laninamivir, respectively). The double E119D/H275Y mutation further increased oseltamivir and peramivir 50% inhibitory concentrations by 790- and >5000-fold, respectively, compared with the WT. The mutant viruses remained susceptible to favipiravir. The NA affinity and velocity values of the E119D variant decreased by 8.1-fold and 4.5-fold, respectively, compared with the WT. Conclusions.âThe actual emergence of a single NA mutation conferring pan-NAI resistance in the clinical setting reinforces the pressing need to develop new anti-influenza strategie
Individual Confidence-Weighting and Group Decision-Making
Group-living species frequently pool individual information so as to reach consensus decisions such as when and where to move, or whether a predator is present. Such opinion-pooling has been demonstrated empirically, and theoretical models have been proposed to explain why group decisions are more reliable than individual decisions. Behavioural ecology theory frequently assumes that all individuals have equal decision-making abilities, but decision theory relaxes this assumption and has been tested in human groups. We summarise relevant theory and argue for its applicability to collective animal decisions. We consider selective pressure on confidence-weighting in groups of related and unrelated individuals. We also consider which species and behaviours may provide evidence of confidence-weighting, paying particular attention to the sophisticated vocal communication of cooperative breeders
Paclitaxel resistance by random mutagenesis of 뱉tubulin
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102075/1/cm21154-sup-0001-suppfig1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102075/2/cm21154-sup-0002-suppfig2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102075/3/cm21154.pd
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