36 research outputs found

    Enabling Astronaut Self-Scheduling using a Robust Advanced Modelling and Scheduling system: an assessment during a Mars analogue mission

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    Human long duration exploration missions (LDEMs) raise a number of technological challenges. This paper addresses the question of the crew autonomy: as the distances increase, the communication delays and constraints tend to prevent the astronauts from being monitored and supported by a real time ground control. Eventually, future planetary missions will necessarily require a form of astronaut self-scheduling. We study the usage of a computer decision-support tool by a crew of analog astronauts, during a Mars simulation mission conducted at the Mars Desert Research Station (MDRS, Mars Society) in Utah. The proposed tool, called Romie, belongs to the new category of Robust Advanced Modelling and Scheduling (RAMS) systems. It allows the crew members (i) to visually model their scientific objectives and constraints, (ii) to compute near-optimal operational schedules while taking uncertainty into account, (iii) to monitor the execution of past and current activities, and (iv) to modify scientific objectives/constraints w.r.t. unforeseen events and opportunistic science. In this study, we empirically measure how the astronauts, who are novice planners, perform at using such a tool when self-scheduling under the realistic assumptions of a simulated Martian planetary habitat

    KEu(MoO4)(2): Polymorphism, Structures, and Luminescent Properties

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    In this paper, with the example of two different polymorphs of KEu(MoO4)(2), the influence of the ordering of the A-cations on the luminescent properties in scheelite related compounds (A',A '') [(B',B '')O-4](m) is investigated. The polymorphs were synthesized using a solid state method. The study confirmed the existence of only two polymorphic forms at annealing temperature range 923-1203 K and ambient pressure: a low temperature anorthic alpha-phase and a monoclinic high temperature beta-phase with an incommensurately modulated structure. The structures of both polymorphs were solved using transmission electron microscopy and refined from synchrotron powder X-ray diffraction data. The monoclinic beta-KEu(MoO4)(2) has a (3+1)-dimensional incommensurately modulated structure (superspace group I2/b(alpha beta 0)00, a = 5.52645(4) angstrom, b = 5.28277(4) angstrom, c = 11.73797(8) angstrom, gamma = 91.2189(4)degrees, q = 0.56821(2)a*-0.12388(3)b*), whereas the anorthic alpha-phase is (3+1)-dimensional commensurately modulated (superspace group I (1) over bar(alpha beta gamma)0, a = 5.58727(22) angstrom, b = 5.29188(18)angstrom, c = 11.7120(4) angstrom, alpha = 90.485(3)degrees, beta = 88.074(3)degrees, gamma = 91.0270(23)degrees, q = 1/2a* + 1/2c*). In both cases the modulation arises due to Eu/K cation ordering at the A site: the formation of a 2-dimensional Eu3+ network is characteristic for the alpha-phase, while a 3-dimensional Eu3+-framework is observed for the beta-phase structure. The luminescent properties of KEu(MoO4)(2) samples prepared under different annealing conditions were measured, and the relation between their optical properties and their structures is discussed

    Un cas de tumeur myofibroblastique inflammatoire maligne compliqué d'une acidose lactique chez une patiente de 38 ans

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    Inflammatory myofibroblastic tumors (IMT) are rare tumors. They were originally described in the lung, but they have been now observed in many others locations, mainly abdominal and pelvic. These tumors are usually benign but their recurrent nature and the presence of an abnormality of chromosome band 2p23 in some of them, suggest that some lesions form a true tumor entity. Surgical excision as complete as possible is the gold standard treatment. We report the case of a 38 years old female, who presented a recurrent metastasizing inflammatory myofibroblastic tumor causing lactic acidosis and other biological abnormalities such as hypercalcemia, hypoalbuminemia, hypoglycemia, disseminated intravascular coagulation and inflammatory syndrome.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Hémangioendothéliome rétiforme :à propos d'un cas.

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    Retiform haemangioendothelioma is a locally aggressive, very rarely metastasizing vascular lesion. Histologically, it is characterized by distinctive arborizing blood vessels resembling "rete testis" and lined by endothelial cells with characteristic hobnail morphology. We present an additional case, in the leg of a 64-year-old patient. We discuss the classification of hemangioendotheliomas. The term hemangioendothelioma should be restricted to vascular tumours of "intermediate malignancy" but has been used to designate tumours with variable histological features and clinical behaviour. Spindle cell hemangio(endothelio)ma is currently regarded as a benign reactive lesion. Kaposiform hemangioendothelioma is potentially lethal due to consumption coagulopathy but no metastasizing case has been reported. Epithelioid hemangioendothelioma is associated with a significant metastatic risk and has been included in the category of malignant vascular tumors. The vascular lesions fulfilling the strict definition of hemangioendothelioma include retiform hemangioendothelioma, papillary intralymphatic angioendothelioma "Dabska's tumor", composite hemangioendothelioma and perhaps the controversial polymorphic hemangioendothelioma.Case ReportsEnglish AbstractJournal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Domain adversarial networks and intensity-based data augmentation for male pelvic organ segmentation in cone beam CT

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    In radiation therapy, a CT image is used to manually delineate the organs and plan the treatment. During the treatment, a cone beam CT (CBCT) is often acquired to monitor the anatomical modifications. For this purpose, automatic organ segmentation on CBCT is a crucial step. However, manual segmentations on CBCT are scarce, and models trained with CT data do not generalize well to CBCT images. We investigate adversarial networks and intensity-based data augmentation, two strategies leveraging large databases of annotated CTs to train neural networks for segmentation on CBCT. Adversarial networks consist of a 3D U-Net segmenter and a domain classifier. The proposed framework is aimed at encouraging the learning of filters producing more accurate segmentations on CBCT. Intensity-based data augmentation consists in modifying the training CT images to reduce the gap between CT and CBCT distributions. The proposed adversarial networks reach DSCs of 0.787, 0.447, and 0.660 for the bladder, rectum, and prostate respectively, which is an improvement over the DSCs of 0.749, 0.179, and 0.629 for "source only" training. Our brightness-based data augmentation reaches DSCs of 0.837, 0.701, and 0.734, which outperforms the morphons registration algorithms for the bladder (0.813) and rectum (0.653), while performing similarly on the prostate (0.731). The proposed adversarial training framework can be used for any segmentation application where training and test distributions differ. Our intensity-based data augmentation can be used for CBCT segmentation to help achieve the prescribed dose on target and lower the dose delivered to healthy organs

    Repurposing as a means to increase the activity of amphotericin B and caspofungin against Candida albicans biofilms

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    Objectives Biofilms of Candida species, often formed on medical devices, are generally resistant to currently available antifungal drugs. The aim of this study was to identify compounds that increase the activity of amphotericin B and caspofungin, commonly used antifungal agents, against Candida biofilms. Methods A library containing off-patent drugs was screened for compounds, termed enhancers, that increase the in vitro activity of amphotericin B against Candida albicans biofilms. Biofilms were grown in 96-well plates and growth was determined by the cell titre blue assay. Synergy between identified enhancers and antifungal agents was further characterized in vitro using fractional inhibitory concentration index (FICI) values and in vivo using a worm biofilm infection model. In light of the application of these enhancers onto implants, their possible effect on the growth potential of MG63 osteoblast-like cells was assessed. Results Pre-incubation of C. albicans biofilms with subinhibitory concentrations of the enhancers drospirenone, perhexiline maleate or toremifene citrate significantly increased the activity of amphotericin B or caspofungin (FICI < 0.5) against C. albicans and Candida glabrata biofilms. Moreover, these enhancers did not affect the growth potential of osteoblasts. Interestingly, toremifene citrate also enhanced the in vitro activity of caspofungin in a mixed biofilm consisting of C. albicans and Staphylococcus epidermidis. Furthermore, we demonstrate synergy between toremifene citrate and caspofungin in an in vivo worm C. albicans biofilm infection model. Conclusions Our data demonstrate an in vitro and in vivo enhancement of the antibiofilm activity of caspofungin by toremifene citrate. Furthermore, our results pave the way for implant-related applications of the identified enhancers.status: publishe

    A practice survey of the evolution of rectal cancer management : a Belgian Federal College of radiotherapy study

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    The aim of the present study was to perform a rectal cancer practice survey in order to reassess in 2005 the Belgian state of the art. A questionnaire based on the past 1999 peer review, supplemented with general questions, was circulated to 16 radiotherapy centres in Belgium. A case was also proposed for treatment planification. In 2005, a formal multidisciplinary team was in place in all visited centres. Endorectal ultrasound, colonoscopy, CEA and an initial pathological diagnosis were standard procedure in all centres. For T1-2N0, the majority of centres do not perform a preoperative treatment; for T3N0, a majority proposes a preoperative radiochemotherapy. For all T3-4 any N, or any T-N involved, a neoadjuvant preoperative treatment is prescribed. Fractionation is conventional (1.8 Gy/d, five times a week). Analysing the practical case, the mean value for CTV and PTV volume was 393 (SD: 126) and 781 cm(3) (SD: 105), respectively. Mean D-min and D-max of 92 and 106.5%, respectively, were measured in the PTV. From clinical point of view, standards concepts are emerging and spreading for staging and for treatment options. Nevertheless, there is still a need for standardization of volumes and delineation standards
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