Paper Session III-A - Electrolytic Oxygen Enrichment Using Supernoxide Ion in a Solid Polymer Membrane Electrolyte

Electrochemical cells are among the technologies under consideration for gaseous oxygen concentration or enrichment in both aerospace and civilian applications. Current electrochemical technology involves the electro-reduction of molecular oxygen, O2, to water at one electrode, and the electro-oxidation of water to oxygen at the other. In terms of the overall chemical mechanism, this is a 4-electron, 4-proton process. From an economic point of view, one would like to use as little energy as possible to effect oxygen transport. The simplest possible mechanistic scenario would be if the O-, reduction product is the superoxide ion, O2~, involving only a single electron exchange: O2 + e = O 2 Superoxide anion can be produced electrochemically via reduction of O 2 in an organic aprotic solvent, such as dimethyl formamide or acetonitrile. Moreover, production of superoxide via electrolysis is electrochemically reversible (i.e., the forward and reverse reaction is so rapid that it proceeds under diffusion control near the thermodynamic potential). Considerable energy savings may be realized if electrochemical O, transport could be performed using superoxide ion

Bleeding Stomal Varices in Portal Hypertension

We report a case of a 50-year-old man with a history of liver cirrhosis and colon cancer post end colostomy presenting to the emergency department with stomal bleeding and passage of clots into the colostomy bag. The patient was treated with transjugular intrahepatic portosystemic shunt (TIPS) and concomitant embolization of the stomal varices via the TIPS shunt using N-butyl cyanoacrylate mixed with ethiodol. Although stomal variceal bleeding is uncommon, this entity can have up to 40% mortality upon initial presentation, given the challenges in diagnosis and management. Currently, there are no established standard treatments for stomal variceal bleeding. In addition, to the best of our knowledge, there are no cases in the current literature in which treatment of this entity is performed with a combination of TIPS shunt placement and N-butyl cyanoacrylate variceal embolization

Combined Transhepatic and Transjugular Approach for Mechanical Thrombectomy of Massive TIPS Thrombosis

Transjugular intrahepatic portosystemic shunt (TIPS) is a well-validated decompressive therapy option to manage ascites and variceal bleeding secondary to portal hypertension. Complications following TIPS procedures include hepatic encephalopathy, liver failure, and TIPS dysfunction. TIPS dysfunction is due to occlusion or stenosis of the TIPS shunt and can be caused by acute or chronic thrombosis. TIPS thrombosis is often treated with mechanical thrombectomy or catheter-directed thrombolytic therapy. Most cases of in-stent occlusion can be treated via a transjugular approach with recanalization or placement of additional stents. We present a case of a 72-year-old female who presented with worsening ascites 17 months after initial TIPS procedure; she was found to have a large thrombus completely occluding the TIPS stent. In our case, a combined transhepatic and transjugular approach was required for TIPS revision given the extent of well-organized clot located near the hepatic venous end of the stent, resulting from prolonged stent occlusion. This was an extremely challenging scenario with two overlapping covered stents and a bare metal stent at the hepatic venous end in the setting of chronic thrombosis and a well-organized fibrous cap. The case highlights the need for optimal initial placement of the primary TIPS shunt to avoid the need for subsequent complex interventions to maintain TIPS shunt patency

Is There a Debt-threshold Effect on Output Growth?

This paper studies the long-run impact of public debt expansion on economic growth and investigates whether the debt-growth relation varies with the level of indebtedness. Our contribution is both theoretical and empirical. On the theoretical side, we develop tests for threshold effects in the context of dynamic heterogeneous panel data models with cross-sectionally dependent errors and illustrate, by means of Monte Carlo experiments, that they perform well in small samples. On the empirical side, using data on a sample of 40 countries (grouped into advanced and developing) over the 1965-2010 period, we and no evidence for a universally applicable threshold effect in the relationship between public debt and economic growth, once we account for the impact of global factors and their spillover effects. Regardless of the threshold, however, we find significant negative long-run effects of public debt build-up on output growth. Provided that public debt is on a downward trajectory, a country with a high level of debt can grow just as fast as its peers

Long-Run Effects in Large Heterogenous Panel Data Models with Cross-Sectionally Correlated Errors

This paper develops a cross-sectionally augmented distributed lag (CS-DL) approach to the estimation of long-run effects in large dynamic heterogeneous panel data models with cross-sectionally dependent errors. The asymptotic distribution of the CS-DL estimator is derived under coefficient heterogeneity in the case where the time dimension (T) and the cross-section dimension (N) are both large. The CS-DL approach is compared with more standard panel data estimators that are based on autoregressive distributed lag (ARDL) specifications. It is shown that unlike the ARDL type estimator, the CS-DL estimator is robust to misspecification of dynamics and error serial correlation. The theoretical results are illustrated with small sample evidence obtained by means of Monte Carlo simulations, which suggest that the performance of the CS-DL approach is often superior to the alternative panel ARDL estimates particularly when T is not too large and lies in the range of 30 _ T < 100

A Counterfactual Economic Analysis of Covid-19 Using a Threshold Augmented Multi-Country Model

This paper develops a threshold-augmented dynamic multi-country model (TG-VAR) to quantify the macroeconomic effects of Covid-19. We show that there exist threshold effects in the relationship between output growth and excess global volatility at individ

Can Italy grow out of its NPL overhang? A panel threshold analysis

This paper examines whether a tipping point exists for real GDP growth in Italy above which the ratio of non-performing loans (NPLs) to total loans falls significantly. Estimating a heterogeneous dynamic panel–threshold model with data on 17 Italian regions over the period 1997–2014, we find that growth above 1.2%, if sustained for a number of years, is associated with a significant decline in the NPL ratio

Reports from spinal cord injury patients: Eight months after the 2003 earthquake in Bam, Iran

OBJECTIVE: The World Health Organization defines disaster as a sudden ecologic phenomenon of sufficient magnitude to require external assistance. On December 26, 2003, the Bam earthquake left more than 200 spinal cord injury (SCI) patients. Our study of these SCI patients and the rehabilitation of disabled persons in Bam may assist in the organization of rehabilitation programs during future disasters. DESIGN: Eight months after the disaster, we planned to visit the SCI patients in Bam. We visited 61 patients in Bam, Baravat, and surrounding villages. We completed a questionnaire during our visit. RESULTS: The patients' mean age was 31.9 ± 9.6 yrs. Twenty-nine (53.7) patients were female, and 25 (46.3) were male. Fifty-two (96.3) patients had pain syndromes, which had started from 3 days to 8 mos after injury. Thirty-three (61) patients used clean intermittent catheterization, and 29 (53.7) did not have bowel programs. Nineteen (35.2) patients had pressure sores. CONCLUSIONS: All aspects of disasters should be considered seriously by all countries. The special needs of people with disabilities during and long after any disaster are important. The impact of disasters on disabled people is magnified because of their condition, so special attention must be paid to this group. © 2007 Lippincott Williams & Wilkins, Inc

Physics-Informed Echo State Networks for Chaotic Systems Forecasting

We propose a physics-informed Echo State Network (ESN) to predict the evolution of chaotic systems. Compared to conventional ESNs, the physics-informed ESNs are trained to solve supervised learning tasks while ensuring that their predictions do not violate physical laws. This is achieved by introducing an additional loss function during the training of the ESNs, which penalizes non-physical predictions without the need of any additional training data. This approach is demonstrated on a chaotic Lorenz system, where the physics-informed ESNs improve the predictability horizon by about two Lyapunov times as compared to conventional ESNs. The proposed framework shows the potential of using machine learning combined with prior physical knowledge to improve the time-accurate prediction of chaotic dynamical systems.Comment: 7 pages, 3 figure