排序方式: 共有20条查询结果,搜索用时 15 毫秒
1.
Emmanuel Margolin Youngjun J. Oh Matthew Verbeek Jason Naude Daniel Ponndorf Yulia Alexandrovna Meshcheriakova Hadrien Peyret Michiel T. van Diepen Ros Chapman Ann E. Meyers George Peter Lomonossoff Nobuyuki Matoba Anna‐Lise Williamson Edward P. Rybicki 《Plant biotechnology journal》2020,18(10):2109-2117
2.
Oliveri Hadrien Traas Jan Godin Christophe Ali Olivier 《Journal of mathematical biology》2019,78(3):625-653
Journal of Mathematical Biology - A crucial question in developmental biology is how cell growth is coordinated in living tissue to generate complex and reproducible shapes. We address this issue... 相似文献
3.
Wei Huang Xin Li Yiyi Chen Xia Li Ming-Ching Chang Matthew J. Oborski Dariya I. Malyarenko Mark Muzi Guido H. Jajamovich Andriy Fedorov Alina Tudorica Sandeep N. Gupta Charles M. Laymon Kenneth I. Marro Hadrien A. Dyvorne James V. Miller Daniel P. Barbodiak Thomas L. Chenevert Jayashree Kalpathy-Cramer 《Translational oncology》2014,7(1):153-166
Pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) time-course data allows estimation of quantitative parameters such as Ktrans (rate constant for plasma/interstitium contrast agent transfer), ve (extravascular extracellular volume fraction), and vp (plasma volume fraction). A plethora of factors in DCE-MRI data acquisition and analysis can affect accuracy and precision of these parameters and, consequently, the utility of quantitative DCE-MRI for assessing therapy response. In this multicenter data analysis challenge, DCE-MRI data acquired at one center from 10 patients with breast cancer before and after the first cycle of neoadjuvant chemotherapy were shared and processed with 12 software tools based on the Tofts model (TM), extended TM, and Shutter-Speed model. Inputs of tumor region of interest definition, pre-contrast T1, and arterial input function were controlled to focus on the variations in parameter value and response prediction capability caused by differences in models and associated algorithms. Considerable parameter variations were observed with the within-subject coefficient of variation (wCV) values for Ktrans and vp being as high as 0.59 and 0.82, respectively. Parameter agreement improved when only algorithms based on the same model were compared, e.g., the Ktrans intraclass correlation coefficient increased to as high as 0.84. Agreement in parameter percentage change was much better than that in absolute parameter value, e.g., the pairwise concordance correlation coefficient improved from 0.047 (for Ktrans) to 0.92 (for Ktrans percentage change) in comparing two TM algorithms. Nearly all algorithms provided good to excellent (univariate logistic regression c-statistic value ranging from 0.8 to 1.0) early prediction of therapy response using the metrics of mean tumor Ktrans and kep (= Ktrans/ve, intravasation rate constant) after the first therapy cycle and the corresponding percentage changes. The results suggest that the interalgorithm parameter variations are largely systematic, which are not likely to significantly affect the utility of DCE-MRI for assessment of therapy response. 相似文献
4.
Cecile Bessou Claudine Basset-Mens Cynthia Latunussa Alice Vélu Hadrien Heitz Henri Vannière Jean-Pierre Caliman 《The International Journal of Life Cycle Assessment》2016,21(3):297-310
Purpose
As highlighted in recent reviews, there is a need to harmonise the way life cycle assessment (LCA) of perennial crops is conducted. In most published LCA on perennial crops, the modelling of the agricultural production is based on data sets for just one productive year. This may be misleading since performance and impacts of the system may greatly vary year by year. The purposes of this study are to analyse how partial modelling of the perennial cycle through non-holistic data collection may affect LCA results and to make recommendations.Methods
Three modelling choices for the perennial crop cycle were tested in parallel in two contrasted LCA case studies: oil palm fruits from Indonesia, and small citrus from Morocco. Modelling choices tested were as follows: (i) a chronological modelling over the complete crop cycle of orchards, (ii) a 3-year average from the productive phase, and (iii) various single years from the productive phase. In both case studies, the system boundary was a cradle-to-farm gate with a functional unit of 1 kg fresh fruits. LCA midpoint impacts were calculated with ReCiPe 2008 in Simapro©V.7. We first analysed how inputs, yields and potential impacts varied over time. We then analysed process contributions in the baseline model, i.e. the chronological modelling, and finally compared LCA results for the various perennial modelling choices.Results and discussion
Agricultural practices, yields and impacts varied over the years especially during the first 3–9 years depending on the case study. In both case studies, the modelling choices to account or not for the whole perennial cycle drastically influenced LCA results. The differences could be explained by the inclusion or not of the yearly variability and the accounting or not of the immature phase, which contributed to 7–40 or 6.5–29 % of all impact categories for oil palm fruit and citrus, respectively.Conclusions
The chosen approach to model the perennial cycle influenced the final LCA results for two contrasted case studies and deserved specific attention. Although data availability may remain the limiting factor in most cases, assumptions can be made to interpolate or extrapolate some data sets or to consolidate data sets from chronosequences (i.e. modular modelling). In all cases, we suggest that the approach chosen to model the perennial cycle and the representativeness of associated collected data should be made transparent and discussed. Further research work is needed to improve the understanding and modelling of perennial crop functioning and LCA assessment.5.
Malal M. Diop Nicolas Moiroux Fabrice Chandre Hadrien Martin-Herrou Pascal Milesi Olayidé Boussari Angélique Porciani Stéphane Duchon Pierrick Labbé Cédric Pennetier 《PloS one》2015,10(4)
In response to the widespread use of control strategies such as Insecticide Treated Nets (ITN), Anopheles mosquitoes have evolved various resistance mechanisms. Kdr is a mutation that provides physiological resistance to the pyrethroid insecticides family (PYR). In the present study, we investigated the effect of the Kdr mutation on the ability of female An. gambiae to locate and penetrate a 1cm-diameter hole in a piece of netting, either treated with insecticide or untreated, to reach a bait in a wind tunnel. Kdr homozygous, PYR-resistant mosquitoes were the least efficient at penetrating an untreated damaged net, with about 51% [39-63] success rate compared to 80% [70-90] and 78% [65-91] for homozygous susceptible and heterozygous respectively. This reduced efficiency, likely due to reduced host-seeking activity, as revealed by mosquito video-tracking, is evidence of a recessive behavioral cost of the mutation. Kdr heterozygous mosquitoes were the most efficient at penetrating nets treated with PYR insecticide, thus providing evidence for overdominance, the rarely-described case of heterozygote advantage conveyed by a single locus. The study also highlights the remarkable capacity of female mosquitoes, whether PYR-resistant or not, to locate holes in bed-nets. 相似文献
6.
Promoter regions of six sugarcane Loading Stem Gene (ScLSG) alleles were analyzed using bioinformatic and transgenic approaches. Stable transgene expression analyses, on multiple independent lines per construct, revealed differences between ScLSG promoters in absolute levels and in tissue-selectivity of luciferase reporter activity. Four promoters drove peak expression in the sucrose-loading zone and maintained substantial expression throughout mature stems. One drove a pattern of gradual increase along the stem maturation profile. In general, stem: root expression ratio increased with plant age. The ScLSG5 promoter had the fewest light-enhanced and root-expression motifs in bioinformatic analysis, and drove the highest level and specificity of transgene expression in stems. This indicates the potential to further improve the stem specificity of ScLSG promoter sequences by eliminating enhancers of expression in other tissues. An intron in the 5′UTR was important for expression strength. The ScLSG promoters will be useful for research and biotechnology in sugarcane, where the tailored expression of transgenes in stems is important for enhanced accumulation of sugar or value-added products, and for development as a bioenergy feedstock. 相似文献
7.
Courtecuisse H Jung H Allard J Duriez C Lee DY Cotin S 《Progress in biophysics and molecular biology》2010,103(2-3):159-168
This article describes a series of contributions in the field of real-time simulation of soft tissue biomechanics. These contributions address various requirements for interactive simulation of complex surgical procedures. In particular, this article presents results in the areas of soft tissue deformation, contact modelling, simulation of cutting, and haptic rendering, which are all relevant to a variety of medical interventions. The contributions described in this article share a common underlying model of deformation and rely on GPU implementations to significantly improve computation times. This consistency in the modelling technique and computational approach ensures coherent results as well as efficient, robust and flexible solutions. 相似文献
8.
Juste A. Goungounga Nathalie Grafféo Hadrien Charvat Roch Giorgi 《Biometrical journal. Biometrische Zeitschrift》2023,65(4):2100210
In the presence of competing causes of event occurrence (e.g., death), the interest might not only be in the overall survival but also in the so-called net survival, that is, the hypothetical survival that would be observed if the disease under study were the only possible cause of death. Net survival estimation is commonly based on the excess hazard approach in which the hazard rate of individuals is assumed to be the sum of a disease-specific and expected hazard rate, supposed to be correctly approximated by the mortality rates obtained from general population life tables. However, this assumption might not be realistic if the study participants are not comparable with the general population. Also, the hierarchical structure of the data can induces a correlation between the outcomes of individuals coming from the same clusters (e.g., hospital, registry). We proposed an excess hazard model that corrects simultaneously for these two sources of bias, instead of dealing with them independently as before. We assessed the performance of this new model and compared it with three similar models, using extensive simulation study, as well as an application to breast cancer data from a multicenter clinical trial. The new model performed better than the others in terms of bias, root mean square error, and empirical coverage rate. The proposed approach might be useful to account simultaneously for the hierarchical structure of the data and the non-comparability bias in studies such as long-term multicenter clinical trials, when there is interest in the estimation of net survival. 相似文献
9.
Jean-Fran?ois Houvenaghel Florence Le Jeune Thibaut Dondaine Aurore Esquevin Gabriel Hadrien Robert Julie Péron Claire Haegelen Sophie Drapier Pierre Jannin Clément Lozachmeur Soizic Argaud Joan Duprez Dominique Drapier Marc Vérin Paul Sauleau 《PloS one》2015,10(10)
Objective
The decrease in verbal fluency in patients with Parkinson’s disease (PD) undergoing subthalamic nucleus deep brain stimulation (STN-DBS) is usually assumed to reflect a frontal lobe-related cognitive dysfunction, although evidence for this is lacking.Methods
To explore its underlying mechanisms, we combined neuropsychological, psychiatric and motor assessments with an examination of brain metabolism using F-18 fluorodeoxyglucose positron emission tomography, in 26 patients with PD, 3 months before and after surgery. We divided these patients into two groups, depending on whether or not they exhibited a postoperative deterioration in either phonemic (10 patients) or semantic (8 patients) fluency. We then compared the STN-DBS groups with and without verbal deterioration on changes in clinical measures and brain metabolism.Results
We did not find any neuropsychological change supporting the presence of an executive dysfunction in patients with a deficit in either phonemic or semantic fluency. Similarly, a comparison of patients with or without impaired fluency on brain metabolism failed to highlight any frontal areas involved in cognitive functions. However, greater changes in cognitive slowdown and apathy were observed in patients with a postoperative decrease in verbal fluency.Conclusions
These results suggest that frontal lobe-related cognitive dysfunction could play only a minor role in the postoperative impairment of phonemic or semantic fluency, and that cognitive slowdown and apathy could have a more decisive influence. Furthermore, the phonemic and semantic impairments appeared to result from the disturbance of distinct mechanisms. 相似文献10.