Directed cell migration by contact guidance in aligned collagenous extracellular matrix (ECM) is a critical enabler of breast cancer dissemination. The mechanisms of this process are poorly ...understood, particularly in 3D, in part because of the lack of efficient methods to generate aligned collagen matrices. To address this technological gap, we propose a simple method to align collagen gels using guided cellular compaction. Our method yields highly aligned, acellular collagen constructs with predictable microstructural features, thus providing a controlled microenvironment for in vitro experiments. Quantifying cell behavior in these anisotropic constructs, we find that breast carcinoma cells are acutely sensitive to the direction and extent of collagen alignment. Further, live cell imaging and analysis of 3D cell migration reveals that alignment of collagen does not alter the total motility of breast cancer cells, but simply redirects their migration to produce largely one-dimensional movement. However, a profoundly enhanced motility in aligned collagen matrices is observed for the subpopulation of carcinoma cells with high tumor initiating and metastatic capacity, termed cancer stem cells (CSCs). Analysis of the biophysical determinants of cell migration show that nuclear deformation is not a critical factor associated with the observed increases in motility for CSCs. Rather, smaller cell size, a high degree of phenotypic plasticity, and increased protrusive activity emerge as vital facilitators of rapid, contact-guided migration of CSCs in aligned 3D collagen matrices.
This paper presents mathematical expressions of dc and ac flashover discharge characteristic constants (n and N) of polluted insulators. It's shown that the proposed relationships of n and N are not ...static and they depend on the parameters of the equivalent electrical circuit and thermal characteristics of discharge. The critical voltages and currents computed using the dynamic equations of n and N we established are found in a good accordance with the experimental ones. Under dc, the temperature of the discharge channel is higher with a positive point than with a negative point. And under ac, the discharge temperature range is almost identical to that one corresponding to the dc positive polarity case.
New developments at synchrotron beamlines and the ongoing upgrades of synchrotron facilities allow the possibility to study complex structures with a much better spatial and temporal resolution than ...ever before. However, the downside is that the data collected are also significantly larger (more than several terabytes) than ever before, and post‐processing and analyzing these data is very challenging to perform manually. This issue can be solved by employing automated methods such as machine learning, which show significantly improved performance in data processing and image segmentation than manual methods. In this work, a 3D U‐net deep convolutional neural network (DCNN) model with four layers and base‐8 characteristic features has been developed to segment precipitates and porosities in synchrotron transmission X‐ray micrograms. Transmission X‐ray microscopy experiments were conducted on micropillars prepared from additively manufactured 316L steel to evaluate precipitate information. After training the 3D U‐net DCNN model, it was used on unseen data and the prediction was compared with manual segmentation. A good agreement was found between both segmentations. An ablation study was performed and revealed that the proposed model showed better statistics than other models with lower numbers of layers and/or characteristic features. The proposed model is able to segment several hundreds of gigabytes of data in a few minutes and could be applied to other materials and tomography techniques. The code and the fitted weights are made available with this paper for any interested researcher to use for their needs (https://github.com/manasvupadhyay/erc‐gamma‐3D‐DCNN).
A 3D U‐net deep convolutional neural network has been developed and tested to segment precipitates in synchrotron‐based X‐ray tomography experiments. Comparison of predicted segmentation showed a good agreement with manual segmentation.
Over the past two decades, ultrasound (US) has become widely accepted to guide safe and accurate insertion of vascular devices in critically ill patients. We emphasize central venous catheter ...insertion, given its broad application in critically ill patients, but also review the use of US for accessing peripheral veins, arteries, the medullary canal, and vessels for institution of extracorporeal life support. To ensure procedural safety and high cannulation success rates we recommend using a systematic protocolized approach for US-guided vascular access in elective clinical situations. A standardized approach minimizes variability in clinical practice, provides a framework for education and training, facilitates implementation, and enables quality analysis. This review will address the state of US-guided vascular access, including current practice and future directions.
This paper is aimed at the study of the influence of the chemical constitution of pollution on dc flashover discharge of high voltage contaminated insulators. It's shown that the type of salt and ...salt mixture has an influence on the critical currents for both polarities but doesn't affect significantly the critical voltages whereas the concentration of insoluble matters (Non Soluble Density Deposit, NSDD) has an influence on both critical current and critical voltage. The discharge parameters characteristics N and n depend on the chemical constitution of pollution, the concentration of NSDD and the polarity of voltage. It's also shown that the most important constituent of the discharge column are water vapour and air; and the transfer of metallic ion has no significant influence on flashover voltage.
This paper is aimed at the influence of the linear non uniformity of pollution layer on critical current I cri and critical flashover voltage V cri of polluted insulator under lightning impulse ...voltage. It is shown that the experimental values of I cri and V cri of uniformly and non-uniformly polluted insulator depends on the configuration of pollution and the polarity of voltage. A mathematical model enabling to compute the flashover discharge characteristic constants (n and N) and the critical thickness of pollution layer and thence the critical characteristics of flashover (current and voltage) is presented. It's also shown that n and N are not static and they depend on the parameters of the equivalent electrical circuit, thermal characteristics of discharge and the condition of propagation. The computed critical voltages are found in a good accordance with the experimental ones while the computed critical currents are higher than the experimental ones. The recalculated critical currents and critical voltages assuming that only a part of the thickness of pollution layer contributes to the conduction phenomena at the interface between the discharge and electrolyte well match to the experimental values. Thus there is an effective thickness of pollution layer which varies linearly with the resistivity of pollution layer.
This paper is aimed at the study of the propagation of discharge at the surface of solid insulator and the development of an analytical model of flashover in air. The experimental results show that ...the critical conditions of flashover are met when the discharge reaches the half of creeping distance. Using electrical equivalent circuit and the impedance criterion, we developed a relationship giving the flashover voltage (FOV). This formula evidences the fact that flashover voltage depends on the discharge temperature, the capacitance and the resistance of solid insulator, and the propagation conditions of the discharge. We also show that the computed FOV are in a good accordance with the experimental data.
En 2018, l’admission dans les services de cardiologie d’un patient de plus de 80 ans pour syndrome coronaire aigu avec sus-décalage du segment ST (SCA ST+) n’est pas rare et il n’est plus ...exceptionnel de traiter des patients nonagénaires. La prise en charge de ces patients au profil de risque élevé, souvent polypathologiques et à la présentation parfois atypique ne repose pas sur des recommandations internationales spécifiques basées sur des études randomisées, comme pour les patients plus jeunes, et doit être individualisée à la lumière de publication de séries ouvertes et de consensus d’experts. Cette mise au point, basée sur la présentation d’un cas clinique, vise à guider le clinicien dans la prise en charge spécifique de ces patients, en allant du tableau initial jusqu’au traitement de sortie, en passant par la stratégie de reperfusion.
Admission in cardiology departments of patients over 80 years old, even nonagenarians, for ST-segment elevation myocardial infarction (STEMI) is not uncommon in 2018. The management of these high risk and polypathological patients, with atypical clinical presentation, is not based on international guidelines or randomized studies, but rather on retrospective studies, expert consensus, and common sense. Each decision has to be individualized to the patient's situation. This review, after a clinical case, aims to guide the clinician in the specific management of these patients, from the symptoms, to reperfusion strategy, and, as fast as possible, hospital discharge.
Background and purpose
The aim is to describe an uncommon phenotype of hereditary ATTR neuropathy with upper limb onset.
Methods
The French TTR Familial Amyloid Polyneuropathy database was used for a ...retrospective evaluation of 32 consecutive patients with upper limb onset of the neuropathy (study group) and they were compared to 31 Portuguese early‐onset patients and 99 late‐onset patients without upper limb onset.
Results
Initial upper limb symptoms were mostly sensory. Lower limb symptoms began 2.3 ± 3 years after upper limb symptoms. Twenty‐four (75%) patients were initially misdiagnosed, with 15 different diagnoses. More patients in the study group had a Neuropathy Impairment Score upper limb/lower limb ratio > 1 compared to the late‐onset patient group. The study group had significantly more pronounced axonal loss in the median and ulnar motor nerves and the ulnar sensory and sural nerves. On radial nerve biopsies (n = 11), epineurial vessels were abnormal in six cases, including amyloid deposits in vessel walls (3/11), with vessel occlusion in two cases.
Conclusion
Upper limb onset of hereditary ATTR neuropathy is not rare in non‐endemic areas. It is important to propose early TTR sequencing of patients with idiopathic upper limb neuropathies, as specific management and treatment are required.
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