Dilated Convolutional Neural Networks for Cardiovascular MR Segmentation in Congenital Heart Disease

We propose an automatic method using dilated convolutional neural networks (CNNs) for segmentation of the myocardium and blood pool in cardiovascular MR (CMR) of patients with congenital heart disease (CHD). Ten training and ten test CMR scans cropped to an ROI around the heart were provided in the MICCAI 2016 HVSMR challenge. A dilated CNN with a receptive field of 131x131 voxels was trained for myocardium and blood pool segmentation in axial, sagittal and coronal image slices. Performance was evaluated within the HVSMR challenge. Automatic segmentation of the test scans resulted in Dice indices of 0.80$\pm$0.06 and 0.93$\pm$0.02, average distances to boundaries of 0.96$\pm$0.31 and 0.89$\pm$0.24 mm, and Hausdorff distances of 6.13$\pm$3.76 and 7.07$\pm$3.01 mm for the myocardium and blood pool, respectively. Segmentation took 41.5$\pm$14.7 s per scan. In conclusion, dilated CNNs trained on a small set of CMR images of CHD patients showing large anatomical variability provide accurate myocardium and blood pool segmentations

Spatial chaos of an extensible conducting rod in a uniform magnetic field

The equilibrium equations for the isotropic Kirchhoff rod are known to form an integrable system. It is also known that the effects of extensibility and shearability of the rod do not break the integrable structure. Nor, as we have shown in a previous paper does the effect of a magnetic field on a conducting rod. Here we show, by means of Mel'nikov analysis, that, remarkably, the combined effects do destroy integrability; that is, the governing equations for an extensible current-carrying rod in a uniform magnetic field are nonintegrable. This result has implications for possible configurations of electrodynamic space tethers and may be relevant for electromechanical devices

Predicción de desgaste abrasivo y dureza superficial de partes impresas por tecnología SLA

In the present study, a prediction of hardness deterioration and abrasive wear was performed through a neural network using artificial intelligence on a material printed in SLA. This article aims to predict the mechanical properties, wear resistance and surface hardness of parts manufactured by SLA stereolithography printing. A full factorial DOE was used to associate the peculiar parameters (print orientation, cure time, layer height) to perform experiments. The mechanical properties were evaluated according to ASTM regulations, with the objective of obtaining feeding data and validation of the predictions of the Taber Wear Index and hardness using an artificial neural network. The experimental results are in good agreement with the measured data with satisfactory prediction errors with a mean square error (MSE) of 0.01 corresponding to abrasive wear using the clear resin and a mean absolute error (MSE) of 0.09 with an R2 of 0.756, the prediction with the neural network with a mean square error (MSE) of 2.47 corresponding to abrasive wear using the tough resin and a mean absolute error (MSE) of 14.3 with an R2 of 0.97. It was shown that the accuracy of the prediction is reasonable, and the network has the potential to be improved if the experimental database for training the network could be expanded. Therefore, wear and hardness mechanical properties can be predicted appropriately with an ANN.En el presente estudio se realizó una predicción del deterioro de la dureza y el desgaste abrasivo a través de una red neuronal utilizando inteligencia artificial sobre un material impreso en SLA. Esta investigación tiene como objetivo predecir las propiedades mecánicas de resistencia al desgaste y dureza superficial de piezas fabricadas mediante impresión por estereolitografía (SLA). Para realizar los experimentos se utilizó un diseño factorial de dos niveles o DOE factorial completo y así asociar los parámetros peculiares (orientación de impresión, tiempo de curado, altura de la capa). Las propiedades mecánicas fueron evaluadas según normativas ASTM, con el objetivo de obtener datos de alimentación y validación de las predicciones del índice de desgaste Taber y la dureza empleando una red neuronal artificial. Los resultados experimentales concuerdan con los datos medidos con errores de predicción satisfactorios con un error cuadrático medio (MSE) de 0,01 correspondiente al desgaste abrasivo utilizando la resina transparente y un error absoluto medio (MSE) de 0,09 con un R2 de 0,76. La predicción con la red neuronal tiene un error cuadrático medio (MSE) de 2.47 perteneciente al desgaste abrasivo utilizando la resina resistente y un error absoluto medio (MSE) de 14,3 con un R2 de 0,97. Se demostró que la precisión de la predicción es razonable, y que la red tiene potencial para mejorar si se pudiera ampliar la base de datos experimental para entrenar la red. Por lo tanto, las propiedades mecánicas de desgaste y dureza se pueden predecir, adecuadamente, con una RNA

Sexual risk reduction among Zambian couples

Zambia has over 1 million HIV infections nationwide and an urban prevalence rate of 23%. This study compared the impact of maleinvolvement in multiple and single session risk reduction interventions among inconsistent condom users in Zambia and the role ofserostatus among HIV-seropositive and serodiscordant couples. Couples (N=392) were randomised into intervention arms. Amonginconsistent condom users at baseline (N=83), condom use increased in both conditions and this increase was maintained over a 12-month period. At 12 months, seronegative men in the multiple session condition increased sexual barrier (male and female condoms)use in comparison with those in the single session condition (F=16.13, p=0.001) while seropositive individuals increased sexualbarrier use regardless of condition. Results illustrate the importance of both single and multiple session risk reduction counsellingamong seronegative men in serodiscordant couples in Zambia, and highlight the differing perception of risk between seropositiveand serodiscordant persons.Keywords: HIV, men, women, Africa, high-risk behaviour, behavioural intervention

Lattice distortions in a sawtooth chain with Heisenberg and Ising bonds

An exactly solvable model of the sawtooth chain with Ising and Heisenberg bonds and with coupling to lattice distortion for Heisenberg bonds is considered in the magnetic field. Using the direct transfer-matrix formalism an exact description of the thermodynamic functions is obtained. The ground state phase diagrams for all regions of parameters values containing phases corresponding to the magnetization plateaus at $M=0,1/4$ and 1/2 have been obtained. Exact formulas for bond distortions for various ground states are presented. A novel mechanism of magnetization plateau stabilization corresponding to $M=1/4$ state is reported.Comment: 16 pages, 12 figure

Prediction of abrasive wear and surface hardness of printed parts by SLA technology

In the present study, a prediction of hardness deterioration and abrasive wear was performed through a neural network using artificial intelligence on a material printed in SLA. This article aims to predict the mechanical properties, wear resistance and surface hardness of parts manufactured by SLA stereolithography printing. A full factorial DOE was used to associate the peculiar parameters (print orientation, cure time, layer height) to perform experiments. The mechanical properties were evaluated according to ASTM regulations, with the objective of obtaining feeding data and validation of the predictions of the Taber Wear Index and hardness using an artificial neural network. The experimental results are in good agreement with the measured data with satisfactory prediction errors with a mean square error (MSE) of 0.01 corresponding to abrasive wear using the clear resin and a mean absolute error (MSE) of 0.09 with an R2 of 0.756, the prediction with the neural network with a mean square error (MSE) of 2.47 corresponding to abrasive wear using the tough resin and a mean absolute error (MSE) of 14.3 with an R2 of 0.97. It was shown that the accuracy of the prediction is reasonable, and the network has the potential to be improved if the experimental database for training the network could be expanded. Therefore, wear and hardness mechanical properties can be predicted appropriately with an ANN

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described

Effectiveness of Nifurtimox Eflornithine Combination Therapy (NECT) in T. b. gambiense second stage sleeping sickness patients in the Democratic Republic of Congo: report from a field study

BACKGROUND: Nifurtimox-eflornithine combination therapy (NECT) for the treatment of second stage gambiense human African trypanosomiasis (HAT) was added to the World Health Organization's Essential Medicines List in 2009 after demonstration of its non-inferior efficacy compared to eflornithine therapy. A study of NECT use in the field showed acceptable safety and high efficacy until hospital discharge in a wide population, including children, pregnant and breastfeeding women, and patients with a HAT treatment history. We present here the effectiveness results after the 24-month follow-up visit. METHODOLOGY/PRINCIPAL FINDINGS: In a multicenter, open label, single arm phase IIIb study, second stage gambiense HAT patients were treated with NECT in the Democratic Republic of Congo. Clinical cure was defined 24 months after treatment as survival without clinical and/or parasitological signs of HAT. Of the 629 included patients, 619 (98.4%) were discharged alive after treatment and were examined for the presence of trypanosomes, white blood cell count in cerebro-spinal fluid, and disease symptoms. The clinical cure rate of 94.1% was comparable for all subpopulations analyzed at the 24-month follow-up visit. Self-reported adverse events during follow-up were few and concerned mainly nervous system disorders, infections, and gastro-intestinal disorders. Overall, 28 patients (4.3%) died during the course of the trial. The death of 16 of the 18 patients who died during the follow-up period was assessed as unlikely or not related to NECT. Within 24 months, eight patients (1.3%) relapsed and received rescue treatment. Sixteen patients were completely lost to follow-up. CONCLUSIONS/SIGNIFICANCE: NECT treatment administered under field conditions was effective and sufficiently well tolerated, no major concern arose for children or pregnant or breastfeeding women. Patients with a previous HAT treatment history had the same response as those who were naive. In conclusion, NECT was confirmed as effective and appropriate for use in a broad population, including vulnerable subpopulations. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov, number NCT00906880

A video guide of five access methods to the splenic flexure: the concept of the splenic flexure box

Aim: The aim of this study was to describe all the possible approaches for laparoscopic splenic flexure mobilization (SFM), each suitable for specific situations, and create an illustrated system to show SFM approaches in an easy and practical way to make it easy to learn and teach. Methods: Two different phases. First part: Cadaver-based study of the colonic splenic flexure anatomy. In order to demonstrate the different approaches, a balloon was placed through the colonic hepatic flexure in the lesser sac without sectioning any of the fixing ligaments of the splenic flexure. Second part: A real case series of laparoscopic SFM. Results: First part: 11 cadavers were dissected. Five potential approaches to SFM were found: anterior, trans-omentum, lateral, medial infra-mesocolic, and medial trans-mesocolic. The illustrative system developed was named: Splenic Flexure “Box”(SFBox). Second part: One of the types of SFM described in first part was used in five patients with colorectal cancer. Each laparoscopic approach to the splenic flexure was illustrated in a video accompanied by illustration aids delineating the access. Conclusion: With the cadaver dissection and subsequent demonstration in real-life laparoscopic surgery, we have shown five types of laparoscopic splenic flexure mobilization. The Splenic Flexure “Box” is a useful way to learn and teach this surgical maneuver

Network 'small-world-ness': a quantitative method for determining canonical network equivalence

Background: Many technological, biological, social, and information networks fall into the broad class of 'small-world' networks: they have tightly interconnected clusters of nodes, and a shortest mean path length that is similar to a matched random graph (same number of nodes and edges). This semi-quantitative definition leads to a categorical distinction ('small/not-small') rather than a quantitative, continuous grading of networks, and can lead to uncertainty about a network's small-world status. Moreover, systems described by small-world networks are often studied using an equivalent canonical network model-the Watts-Strogatz (WS) model. However, the process of establishing an equivalent WS model is imprecise and there is a pressing need to discover ways in which this equivalence may be quantified. Methodology/Principal Findings: We defined a precise measure of 'small-world-ness' S based on the trade off between high local clustering and short path length. A network is now deemed a 'small-world' if S. 1-an assertion which may be tested statistically. We then examined the behavior of S on a large data-set of real-world systems. We found that all these systems were linked by a linear relationship between their S values and the network size n. Moreover, we show a method for assigning a unique Watts-Strogatz (WS) model to any real-world network, and show analytically that the WS models associated with our sample of networks also show linearity between S and n. Linearity between S and n is not, however, inevitable, and neither is S maximal for an arbitrary network of given size. Linearity may, however, be explained by a common limiting growth process. Conclusions/Significance: We have shown how the notion of a small-world network may be quantified. Several key properties of the metric are described and the use of WS canonical models is placed on a more secure footing