Functional Critical Aortic Stenosis with Transient Retrograde Flow in a Neonate with Left Diaphragmatic Hernia

We report a neonate with left congenital diaphragmatic hernia and severe left ventricular dysfunction, in whom the blood flow in the transverse arch and its branches was supported in a retrograde fashion by patent ductus arteriosus. There was only minimal antegrade flow across the aortic valve and hemodynamic physiology resembled critical aortic stenosis, necessitating the immediate use of prostaglandin E1 infusion to maintain the patent ductus arteriosus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98145/1/chd679.pd

Melting in multilayer adsorbed films

We present both an improved model and new experimental data concerning the problem of melting in multilayer adsorbed films. The model treats in a mutually consistent manner all interfaces in a stratified film. This results in the prediction of substrate freezing, a phenomenon thermodynamically analogous to surface melting. We also compare the free energies of stratified films to those of homogeneous films. This leads to an orderly classification of multilayer phase diagrams in the vicinity of the bulk triple point. The results of the model are compared with the experimentally known systems. Of these, only methane/graphite exhibits melting from homogeneous solid to homogeneous liquid in multilayer films. The systems Ne/graphite and Ar/graphite, studied by Zhu and Dash, exhibit surface melting and substrate freezing instead. We observe experimentally, by means of pulsed nuclear magnetic resonance, that melting in methane adsorbed on graphite extends below the film thickness at which the latent heat of melting is known to vanish. The multilayer melting curve in this system is a first-order prewetting transition, extending from triple-point dewetting at bulk coexistence down to a critical point where the latent heat vanishes at about four layers, and apparently extending to thinner films as a higher-order, two-dimensional phase transition. It would therefore seem that methane/graphite is an ideal system in which to study the evolution of melting from two dimensions to three dimensions

The Patterns of High-Level Magnetic Activity Occurring on the Surface of V1285 Aql: The OPEA Model of Flares and DFT Models of Stellar Spots

Statistically analyzing Johnson UBVR observations of V1285 Aql during the three observing seasons, both activity level and behavior of the star are discussed in respect to obtained results. We also discuss the out-of-flare variation due to rotational modulation. Eighty-three flares were detected in the U-band observations of season 2006 . First, depending on statistical analyses using the independent samples t-test, the flares were divided into two classes as the fast and the slow flares. According to the results of the test, there is a difference of about 73 s between the flare-equivalent durations of slow and fast flares. The difference should be the difference mentioned in the theoretical models. Second, using the one-phase exponential association function, the distribution of the flare-equivalent durations versus the flare total durations was modeled. Analyzing the model, some parameters such as plateau, half-life values, mean average of the flare-equivalent durations, maximum flare rise, and total duration times are derived. The plateau value, which is an indicator of the saturation level of white-light flares, was derived as 2.421{\pm}0.058 s in this model, while half-life is computed as 201 s. Analyses showed that observed maximum value of flare total duration is 4641 s, while observed maximum flare rise time is 1817 s. According to these results, although computed energies of the flares occurring on the surface of V1285 Aql are generally lower than those of other stars, the length of its flaring loop can be higher than those of more active stars.Comment: 44 pages, 10 figures, 5 tables, 2011PASP..123..659

Performance principles for trusted computing with intel SGX

Accepted manuscript version of the following article Gjerdrum, A.T., Pettersen, R., Johansen, H.D. & Johansen, D. (2018). Performance principles for trusted computing with intel SGX. Communications in Computer and Information Science, 864. © Springer International Publishing AG, part of Springer Nature 2018. Published version available at https://doi.org/10.1007/978-3-319-94959-8_1.Cloud providers offering Software-as-a-Service (SaaS) are increasingly being trusted by customers to store sensitive data. Companies often monetize such personal data through curation and analysis, providing customers with personalized application experiences and targeted advertisements. Personal data is often accompanied by strict privacy and security policies, requiring data processing to be governed by non-trivial enforcement mechanisms. Moreover, to offset the cost of hosting the potentially large amounts of data privately, SaaS companies even employ Infrastructure-as-a-Service (IaaS) cloud providers not under the direct supervision of the administrative entity responsible for the data. Intel Software Guard Extensions (SGX) is a recent trusted computing technology that can mitigate some of these privacy and security concerns through the remote attestation of computations, establishing trust on hardware residing outside the administrative domain. This paper investigates and demonstrates the added cost of using SGX, and further argues that great care must be taken when designing system software in order to avoid the performance penalty incurred by trusted computing. We describe these costs and present eight specific principles that application authors should follow to increase the performance of their trusted computing systems

Analysis and modeling of high temporal resolution spectroscopic observations of flares on AD Leo

We report the results of a high temporal resolution spectroscopic monitoring of the flare star AD Leo. During 4 nights, more than 600 spectra were taken in the optical range using the Isaac Newton Telescope (INT) and the Intermediate Dispersion Spectrograph (IDS). We have observed a large number of short and weak flares occurring very frequently (flare activity > 0.71 hours-1). This is in favour of the very important role that flares can play in stellar coronal heating. The detected flares are non white-light flares and, though most of solar flares belong to this kind, very few such events had been previously observed on stars. The behaviour of different chromospheric lines (Balmer series from H_alpha to H_11, Ca II H & K, Na I D_1 & D_2, He I 4026 AA and He I D_3) has been studied in detail for a total of 14 flares. We have also estimated the physical parameters of the flaring plasma by using a procedure which assumes a simplified slab model of flares. All the obtained physical parameters are consistent with previously derived values for stellar flares, and the areas - less than 2.3% of the stellar surface - are comparable with the size inferred for other solar and stellar flares. Finally, we have studied the relationships between the physical parameters and the area, duration, maximum flux and energy released during the detected flares.Comment: Latex file with 17 pages, 11 figures. Available at http://www.ucm.es/info/Astrof/invest/actividad/actividad_pub.html Accepted for publication in: Astronomy & Astrophysics (A&A

Mitral Valve Surgery for Severe Mitral Regurgitation and Dilated Cardiomyopathy—A Bridge to Transplant: Case Report and a Review of Literature

We report a child with myocardial necrosis, dilated cardiomyopathy, and severe mitral valve (MV) regurgitation following neonatal enteroviral myocarditis. He underwent MV annuloplasty at 18 months and MV replacement at 3 years of age. He remains asymptomatic on medical therapy at 8 years of age. Mitral valve surgery may stabilize the evolution of dilated cardiomyopathy and delay the ultimate need for heart transplant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93665/1/chd626.pd

Proton tracking in a high-granularity Digital Tracking Calorimeter for proton CT purposes

Radiation therapy with protons as of today utilizes information from x-ray CT in order to estimate the proton stopping power of the traversed tissue in a patient. The conversion from x-ray attenuation to proton stopping power in tissue introduces range uncertainties of the order of 2-3% of the range, uncertainties that are contributing to an increase of the necessary planning margins added to the target volume in a patient. Imaging methods and modalities, such as Dual Energy CT and proton CT, have come into consideration in the pursuit of obtaining an as good as possible estimate of the proton stopping power. In this study, a Digital Tracking Calorimeter is benchmarked for proof-of-concept for proton CT purposes. The Digital Tracking Calorimeteris applied for reconstruction of the tracks and energies of individual high energy protons. The presented prototype forms the basis for a proton CT system using a single technology for tracking and calorimetry. This advantage simplifies the setup and reduces the cost of a proton CT system assembly, and it is a unique feature of the Digital Tracking Calorimeter. Data from the AGORFIRM beamline at KVI-CART in Groningen in the Netherlands and Monte Carlo simulation results are used to in order to develop a tracking algorithm for the estimation of the residual ranges of a high number of concurrent proton tracks. The range of the individual protons can at present be estimated with a resolution of 4%. The readout system for this prototype is able to handle an effective proton frequency of 1 MHz by using 500 concurrent proton tracks in each readout frame, which is at the high end range of present similar prototypes. A future further optimized prototype will enable a high-speed and more accurate determination of the ranges of individual protons in a therapeutic beam.Comment: 21 pages, 8 figure

Central Venous Catheter-Associated Pericardial Tamponade in a 6-Day Old: A Case Report

Introduction. Pericardial effusion (PCE) and tamponade can cause significant morbidity and mortality in neonates. Such cases have been reported in the literature in various contexts. Case Presentation. A 6-day old neonate with meconium aspiration syndrome and persistent pulmonary hypertension of newborn on high frequency oscillator ventilation and inhaled nitric oxide was referred to our hospital with a large pericardial effusion causing hemodynamic compromise. Prompt pericardiocentesis led to significant improvement in the cardio-respiratory status and removal of the central line prevented the fluid from reaccumulating. Cellular and biochemical analysis aided in the diagnosis of catheter related etiology with possibility of infusate diffusion into the pericardial space. Conclusion. We present this paper to emphasize the importance of recognizing this uncommon but serious complication of central venous catheters in intensive care units. We also discuss the proposed hypothesis for the mechanism of production of PCE

Predictors of Left Ventricular Remodeling after Aortic Valve Replacement in Pediatric Patients with Isolated Aortic Regurgitation

Objective. To identify the risk factors that could predict postoperative outcome after aortic valve replacement in pediatric patients with isolated aortic regurgitation ( AR ). Background. There is controversy regarding the appropriate timing of surgery in asymptomatic or minimally symptomatic patients with isolated AR . In the pediatric age group, there are limited studies in this regard and most of them are on combined aortic valve stenosis and regurgitation. Methods. All patients with biventricular physiology and morphologic left ventricle ( LV ) who underwent aortic valve surgery for AR from J anuary 1988 to J uly 2010 were included in the study. Demographic, clinical, and echocardiographic data were collected at presurgical visit, early postoperative, 1 year, and most recent follow‐up. Results. Among 53 patients (36 males), 18 had LV end‐diastolic diameter ( LVEDD ) z ‐score >4 standard deviation ( SD ) (group I ) and 35 had LVEDD 4 SD predicted persistent LV dilation (>2 SD ) at early post‐op ( P  4 SD ) are significant predictors of incomplete LV remodeling or persistent LV dysfunction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97538/1/chd703.pd