Attenuation Imaging with Pulse-Echo Ultrasound based on an Acoustic Reflector

Ultrasound attenuation is caused by absorption and scattering in tissue and is thus a function of tissue composition, hence its imaging offers great potential for screening and differential diagnosis. In this paper we propose a novel method that allows to reconstruct spatial attenuation distribution in tissue based on computed tomography, using reflections from a passive acoustic reflector. This requires a standard ultrasound transducer operating in pulse-echo mode, thus it can be implemented on conventional ultrasound systems with minor modifications. We use calibration with water measurements in order to normalize measurements for quantitative imaging of attenuation. In contrast to earlier techniques, we herein show that attenuation reconstructions are possible without any geometric prior on the inclusion location or shape. We present a quantitative evaluation of reconstructions based on simulations, gelatin phantoms, and ex-vivo bovine skeletal muscle tissue, achieving contrast-to-noise ratio of up to 2.3 for an inclusion in ex-vivo tissue.Comment: Accepted at MICCAI 2019 (International Conference on Medical Image Computing and Computer Assisted Intervention

Photofission of heavy nuclei at energies up to 4 GeV

Total photofission cross sections for 238U, 235U, 233U, 237Np, 232Th, and natPb have been measured simultaneously, using tagged photons in the energy range Egamma=0.17-3.84 GeV. This was the first experiment performed using the Photon Tagging Facility in Hall B at Jefferson Lab. Our results show that the photofission cross section for 238U relative to that for 237Np is about 80%, implying the presence of important processes that compete with fission. We also observe that the relative photofission cross sections do not depend strongly on the incident photon energy over this entire energy range. If we assume that for 237Np the photofission probability is equal to unity, we observe a significant shadowing effect starting below 1.5 GeV.Comment: 4 pages of RevTex, 6 postscript figures, Submitted to Phys. Rev. Let

Innermost stable circular orbits around magnetized rotating massive stars

In 1998, Shibata and Sasaki [Phys. Rev. D 58, 104011 (1998)] presented an approximate analytical formula for the radius of the innermost stable circular orbit (ISCO) of a neutral test particle around a massive, rotating and deformed source. In the present paper, we generalize their expression by including the magnetic dipole moment. We show that our approximate analytical formulas are accurate enough by comparing them with the six-parametric exact solution calculated by Pach\'on et. al. [Phys. Rev. D 73, 104038 (2006)] along with the numerical data presented by Berti and Stergioulas [MNRAS 350, 1416 (2004)] for realistic neutron stars. As a main result, we find that in general, the radius at ISCO exhibits a decreasing behavior with increasing magnetic field. However, for magnetic fields below 100GT the variation of the radius at ISCO is negligible and hence the non-magnetized approximate expression can be used. In addition, we derive approximate analytical formulas for angular velocity, energy and angular momentum of the test particle at ISCO.Comment: 8 pages, 3 figure

Gravitational Equilibrium in the Presence of a Positive Cosmological Constant

We reconsider the virial theorem in the presence of a positive cosmological constant Lambda. Assuming steady state, we derive an inequality of the form rho >= A (Lambda / 4 pi GN) for the mean density rho of the astrophysical object. With a minimum at Asphere = 2, its value can increase by several orders of magnitude as the shape of the object deviates from a spherically symmetric one. This, among others, indicates that flattened matter distributions like e.g. clusters or superclusters, with low density, cannot be in gravitational equilibrium.Comment: 7 pages, no figure

Electrophysiological and morphological heterogeneity of slow firing neurons in medial septal/diagonal band complex as revealed by cluster analysis

Slow firing septal neurons modulate hippocampal and neocortical functions. Electrophysiologically, it is unclear whether slow firing neurons belong to a homogeneous neuronal population. To address this issue, whole-cell patch recordings and neuronal reconstructions were performed on rat brain slices containing the medial septum/diagonal band complex (MS/DB). Slow firing neurons were identified by their low firing rate at threshold (\u3c 5Hz) and lack of time-dependent inward rectification (Ih). Unsupervised cluster analysis was used to investigate whether slow firing neurons could be further classified into different subtypes. The parameters used for the cluster analysis included latency for first spike, slow afterhyperpolarizing potential, maximal frequency and action potential (AP) decay slope. Neurons were grouped into three major subtypes. The majority of neurons (55%) were grouped as cluster I. Cluster II (17% of neurons) exhibited longer latency for generation of the first action potential (246.5±20.1 ms). Cluster III (28% of neurons) exhibited higher maximal firing frequency (25.3±1.7 Hz) when compared to cluster I (12.3±0.9 Hz) and cluster II (11.8±1.1 Hz) neurons. Additionally, cluster III neurons exhibited faster action potentials at suprathreshold. Interestingly, cluster II neurons were frequently located in the medial septum whereas neurons in cluster I and III appeared scattered throughout all MS/DB regions. Sholl’s analysis revealed a more complex dendritic arborization in cluster III neurons. Cluster I and II neurons exhibited characteristics of “true” slow firing neurons whereas cluster III neurons exhibited higher frequency firing patterns. Several neurons were labeled with a cholinergic marker, Cy3-conjugated 192 IgG (p75NTR), and cholinergic neurons were found to be distributed among the three clusters. Our findings indicate that slow firing medial septal neurons are heterogeneous and that soma location is an important determinant of their electrophysiological properties. Thus, slow firing neurons from different septal regions have distinct functional properties, most likely related to their diverse connectivity

Predicting Adverse Outcomes in Chronic Kidney Disease Using Machine Learning Methods: Data from the Modification of Diet in Renal Disease

Background: Understanding factors which predict progression of renal failure is of great interest to clinicians. Objectives: We examined machine learning methods to predict the composite outcome of death, dialysis or doubling of serum creatinine using the modification of diet in renal disease (MDRD) data set. Methods: We specifically evaluated a generalized linear model, a support vector machine, a decision tree, a feed-forward neural network and a random forest evaluated within the context of 10 fold validation using the CARET package available within the open source architecture R program. Results: We found that using clinical parameters available at entry into the study, these computer learning methods trained on 70% of the MDRD population had prediction accuracies ranging from 66-77% on the remaining 30%. Although the support vector machine methodology appeared to have the highest accuracy, all models studied worked relatively well. Conclusions: These results illustrate the utility of employing machine learning methods within R to address the prediction of long term clinical outcomes using initial clinical measurements

Design of the HEM-POWR study:A prospective, observational study of real-world treatment with damoctocog alfa pegol in patients with haemophilia A

INTRODUCTION: Haemophilia A is a rare bleeding disorder caused by defects in coagulation factor VIII (FVIII). Damoctocog alfa pegol (BAY 94–9027, Jivi, Bayer, Germany) is a site-specifically PEGylated, extended-half-life, recombinant FVIII, approved for use in previously treated patients (PTPs) aged ≥12 years with haemophilia A. However, a real-world evidence regarding routine clinical use of damoctocog alfa pegol is limited. METHODS AND ANALYSIS: HEM-POWR is a multinational, multicentre, non-interventional, prospective, postmarketing cohort study evaluating the effectiveness and safety of real-world treatment with damoctocog alfa pegol. Estimated enrolment is ≥200 PTPs with haemophilia A, receiving damoctocog alfa pegol (on-demand, prophylaxis or intermittent prophylaxis (as per local label)), observed for 36 months. Primary outcomes are total bleeding events and annualised bleeding rate; secondary outcomes include long-term safety, joint health, pharmacokinetics, patient-reported outcomes (PROs) from validated questionnaires and perioperative haemostasis. Where applicable, reasons for switching to damoctocog alfa pegol, choice of treatment regimen and dose will also be captured. Exploratory and descriptive statistical analyses will be performed, and will be stratified by parameters including, but not limited to, prophylaxis regimen and haemophilia severity. Patients can record bleeds and consumption in electronic (e) Diaries, ePROs, and can access non-promotional study information (videos explaining study procedures) via an online patient portal. Optionally, patients can enrol in the LIFE-ACTIVE substudy designed to investigate the relationship between activity (measured by the ActiGraph CP Insight watch) and effectiveness parameters collected from HEM-POWR. ETHICS AND DISSEMINATION: Study approval was obtained by local independent ethics committees and authorities in participating study centres across Europe, the Americas and Asia. Informed consent from patients or their legal representative is a requirement for participation. The study results will be submitted for publication in a peer-reviewed scientific journal and presented at scientific conferences. TRIAL REGISTRATION NUMBERS: NCT03932201, EUPAS26416. PROTOCOL VERSION AND DATE: V.1.2, 27 September 2019

Adiposity Predicts Pulse Pressure in Subjects with Chronic Kidney Disease: Data from the Modification of Diet in Renal Disease

Obesity is a known risk factor for hypertension, but the mechanisms by which this occurs are still unclear. As the body mass index (BMI) is frequently used to define obesity, but the BMI does not distinguish between adipose and other tissues, we sought to develop another index of obesity. We decided to look at the ratio of BMI to urinary creatinine excretion as the latter measurement is believed to be an index of muscle mass. We used data from the modification of diet in renal disease (MDRD) study as urinary creatinine collections and blood pressure measurements were readily available in this data set. The UCRV correlated well with lean body mass determined by anthropomorphic measurements available on this data set. We found that the BMI/UCRV ratio correlated with either percent body fat (PBF) or total body fat calculated as the product of PBF and weight. We also found that the BMI/UCRV ratio correlated significantly with systolic, diastolic and especially pulse pressure in this population. These data suggest that adipocyte mass has a relationship to blood pressure in subjects with renal disease. Should these data be confirmed in other populations, the BMI/UCRV ratio may prove to be a useful measurement in patients at risk for hypertension and other cardiovascular diseases

Reining in Punitive Discipline: Recent Trends in Exclusionary School Discipline Disparities

Concerns around disparities in suspensions and expulsions from schools in the United States have resulted in a concerted effort to reduce the use of exclusionary school discipline. In this article, the authors describe trends in the use of exclusionary discipline in Indiana and Oregon, two U.S. states with different school discipline policy climates. The findings point to a substantial decline in the use of suspensions and other forms of exclusionary discipline in both states. The authors further find that racial and socioeconomic disparities have recently narrowed in both states, though Black students and students who were identified as economically disadvantaged remain likely to be disproportionately exposed to exclusionary discipline. These trends, and their timing, illustrate the broad-based change in disciplinary norms that has occurred in the U.S. over the past decade

Systematic determination of the reproductive growth stage most sensitive to high night temperature stress in rice ( Oryza sativa )

High night‐temperature (HNT) stress during the reproductive stage of rice (Oryza sativa L.) reduces spikelet fertility and yield by inhibiting important physiological processes. However, specifics such as the period of time that is most sensitive to HNT, is unknown. To investigate this, we conducted four controlled‐environment experiments with two rice cultivars, N22 (HNT tolerant) and WAB56–104 (HNT susceptible). These cultivars were exposed to varying durations and intensities of night temperatures (control, 24°C; HNT, 30 and 35°C) during the reproductive stage. The effect of HNT on spikelet fertility and grain weight varied with duration: spikelet fertility reduced by 47–77% when exposed to HNT for 15 nights, 6–29% when exposed for four nights, and 9–15% when exposed for 5.5 h (pre‐midnight, 1830–0000 h or post‐midnight, 0000–0530 h) for four nights. Spikelet fertility and grain weight were most sensitive to HNT during the first 4 d of anthesis, compared with 1–4, 5–8, and 9–12 d before anthesis. At anthesis, reduction in spikelet fertility did not differ significantly between pre‐ and post‐midnight high‐temperature treatments. Our results suggest that greatest sensitivity to HNT during the reproductive stage occurs during the first 4 d of anthesis, providing a reference for future studies involving HNT tolerance in rice