6,192 research outputs found
Consumptive hypothyroidism in a patient with malignant rhabdoid tumor of the kidney: case report on a newly found association
Introduction: Consumptive hypothyroidism is a rare paraneoplastic condition most commonly associated with infantile hemangiomas. It is caused by overexpression of deiodinase type 3 (D3), which leads to preferential conversion of thyroxine to the metabolically inactive reverse triiodothyronine (rT3), paralleled by a decrease of the biologically active T3. Case presentation: A 46-year-old male patient with previously normal thyroid function was diagnosed with a renal carcinoma with rhabdoid differentiation. He was treated with sunitinib, followed by the immune checkpoint inhibitors ipilimumab and nivolumab, and he developed primary hypothyroidism secondary to thyroiditis. Substitution with unusually high doses of levothyroxine as high as 4.3 mu g/kg/day did not normalize his thyroid function. Poor compliance was refuted because there was no improvement after observed administration. He had no malabsorption. Although tyrosine kinase inhibitors can increase the expression of D3, this effect tends to be modest. Therefore, the suspicion of tumor-related consumptive hypothyroidism was raised and supported by low free T3 and elevated rT3 levels. The therapy could not be further modified because the patient opted for palliative care and passed away 12 days later.Immunohistochemistry of the tumor from a sample obtained prior to systemic therapy documented abundant expression of D3, corroborating the diagnosis of consumptive hypothyroidism. Conclusions: This observation extends the spectrum of malignancies overexpressing D3. Although rare, increased awareness of this paraneoplastic syndrome is key, if persistent hypothyroidism cannot be explained by compliance issues or malabsorption. Substitution with high doses of levothyroxine, and combination therapy with liothyronine, can correct hypothyroidism in these patients
Efficient Behavior of Small-World Networks
We introduce the concept of efficiency of a network, measuring how
efficiently it exchanges information. By using this simple measure small-world
networks are seen as systems that are both globally and locally efficient. This
allows to give a clear physical meaning to the concept of small-world, and also
to perform a precise quantitative a nalysis of both weighted and unweighted
networks. We study neural networks and man-made communication and
transportation systems and we show that the underlying general principle of
their construction is in fact a small-world principle of high efficiency.Comment: 1 figure, 2 tables. Revised version. Accepted for publication in
Phys. Rev. Let
A model for cascading failures in complex networks
Large but rare cascades triggered by small initial shocks are present in most
of the infrastructure networks. Here we present a simple model for cascading
failures based on the dynamical redistribution of the flow on the network. We
show that the breakdown of a single node is sufficient to collapse the
efficiency of the entire system if the node is among the ones with largest
load. This is particularly important for real-world networks with an highly
hetereogeneous distribution of loads as the Internet and electrical power
grids.Comment: 4 pages, 4 figure
Transfer Learning for Domain Adaptation in MRI: Application in Brain Lesion Segmentation
Magnetic Resonance Imaging (MRI) is widely used in routine clinical diagnosis
and treatment. However, variations in MRI acquisition protocols result in
different appearances of normal and diseased tissue in the images.
Convolutional neural networks (CNNs), which have shown to be successful in many
medical image analysis tasks, are typically sensitive to the variations in
imaging protocols. Therefore, in many cases, networks trained on data acquired
with one MRI protocol, do not perform satisfactorily on data acquired with
different protocols. This limits the use of models trained with large annotated
legacy datasets on a new dataset with a different domain which is often a
recurring situation in clinical settings. In this study, we aim to answer the
following central questions regarding domain adaptation in medical image
analysis: Given a fitted legacy model, 1) How much data from the new domain is
required for a decent adaptation of the original network?; and, 2) What portion
of the pre-trained model parameters should be retrained given a certain number
of the new domain training samples? To address these questions, we conducted
extensive experiments in white matter hyperintensity segmentation task. We
trained a CNN on legacy MR images of brain and evaluated the performance of the
domain-adapted network on the same task with images from a different domain. We
then compared the performance of the model to the surrogate scenarios where
either the same trained network is used or a new network is trained from
scratch on the new dataset.The domain-adapted network tuned only by two
training examples achieved a Dice score of 0.63 substantially outperforming a
similar network trained on the same set of examples from scratch.Comment: 8 pages, 3 figure
Electromagnetic filaments and edge modifications induced by electrode biasing in the RFX-mod tokamak
Fannia pusio's (Wied.) (Diptera: Fanniidae) life table
Several aspects of the population dynamic of F. pusio (Wiedemann) were studied in the laboratory. Adults were collected in Monte-Mor, SP, Brazil. Adults were kept in the laboratory and were fed with powdered milk, sugar and brewers yeast. Water was offered in separate vials. Fermented food for laboratory animals was used as oviposition medium. The reprodutive rate (Ro) and the rate of natural increase (Rm) were higher at 27ºC, with rates of 48,18 and 0,1849, respectively. The greater generation time occurred at 20ºC.Vários aspectos da dinâmica populacional de F. pusio (Wiedemann) foram estudados no laboratório. Os adultos foram coletados em Monte-Mor, SP, Brasil. Os adultos foram mantidos no laboratório e alimentavam-se de um meio rico em leite em pó, açúcar, levedo de cerveja e gaze embebida em água. Como meio de oviposição forneceu-se ração fermentada de animal. A taxa reprodutiva (Ro) e a taxa de incremento natural (Rm), mais elevada ocorreram a 27ºC com taxa de 48,18 e 0,1849, respectivamente. O maior tempo de geração foi a 20ºC.55756
Design of the new electromagnetic measurement system for RFX-mod upgrade
A major modification of the RFX-mod toroidal load assembly has been decided in order to improve passive MHD control and to minimize the braking torque on the plasma, thus extending the operational space in both RFP and Tokamak configurations. With the removal of the vacuum vessel, the support structure will be modified in order to obtain a new vacuum-tight chamber and the first wall tiles will be directly in front of the passive stabilizing shell inside of it, so increasing both the poloidal cross section and the plasma-shell proximity.
This implies the design of a new vacuum fit electromagnetic measurement system. The new local probes will be installed in vacuum onto the copper shell, behind the graphite tiles, and shall operate up to a maximum temperature of 180\ub0C to allow for baking cycles for first wall conditioning. Because of the reduced room available, tri-axial pickup probes have been designed, with the additional advantage of allowing the minimization of alignment errors.
The paper describes the detailed design of the new probe set, in particular highlighting advantages and effectiveness of different probe solutions. Preliminary tests carried out on local probe prototypes to characterize their electromagnetic behaviour are also reported
Knee position at the moment of bone bruise could reflect the late phase of non-contact anterior cruciate ligament injury rather than the mechanisms leading to ligament failure
Purpose: The aim of the present study was to trace knee position at the time of bone bruise (BB) and investigate how much this position departed from the knee biomechanics of an in vivo flexion–extension. Methods: From an original cohort of 62 patients, seven (11%) presented bicompartmental edemas and were included in the study. 3D models of bones and BB were obtained from MRI. Matching bone edemas, a reconstruction of the knee at the moment of BB was obtained. For the same patients, knee kinematics of a squat was calculated using dynamic Roentgen sterephotogrammetric analysis (RSA). Data describing knee position at the moment of BB were compared to kinematics of the same knee extrapolated from RSA system. Results: Knee positions at the moment of BB was significantly different from the kinematics of the squat. In particular, all the patients’ positions were out of squat range for both anterior and proximal tibial translation, varus–valgus rotation (five in valgus and two in varus), tibial internal–external rotation (all but one, five externally and one internally). A direct comparison at same flexion angle between knee at the moment of BB (average 46.1° ± 3.8°) and knee during squat confirmed that tibia in the former was significantly more anterior (p < 0.0001), more externally rotated (6.1 ± 3.7°, p = 0.04), and valgus (4.1 ± 2.4°, p = 0.03). Conclusion: Knee position at the moment of Bone bruise position was out of physiological in-vivo knee range of motion and could reflect a locked anterior subluxation occurring in the late phase of ACL injury rather than the mechanism leading to ligament failure. Level of evidence: Level I
Photosynthetic and antioxidant responses to drought during sugarcane ripening
Water deficit is an important exogenous factor that enhances the influx of sucrose into sugarcane (Saccharum spp.) stem internodes during ripening, when photosynthetic ability in supplying sinks is essential. The aim of this study was to test the hypothesis that drought tolerance in sugarcane is associated with an effective antioxidant protection during the ripening phase that might maintain a favorable redox balance in chloroplasts and protect photosynthesis under drought conditions. Two commercial sugarcane varieties, IACSP94-2094 (tolerant) and IACSP96-2042 (sensitive), with contrasting behavior under water deficit, were subjected to water withholding during the ripening stage. Our results revealed that the tolerant variety was less affected by water deficit, maintaining hotosynthesis for a longer period and showing a faster recovery after rehydration as compared to the sensitive one. As consequence, the tolerant variety faced lesser excess of light energy at PSII. The maintenance of photosynthesis under water deficit and its fast recovery after rehydration resulted in the lower leaf H2O2 concentration and favorable redox status in the drought-tolerant genotype, which was associated with stimulation of superoxide dismutase during ripening. Our results also revealed that ferric superoxide dismutase isoforms were strongly enhanced under drought conditions, playing an important role in chloroplast redox homeostasis53454755
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