AdaLip: An Adaptive Learning Rate Method per Layer for Stochastic Optimization

Various works have been published around the optimization of Neural Networks that emphasize the significance of the learning rate. In this study we analyze the need for a different treatment for each layer and how this affects training. We propose a novel optimization technique, called AdaLip, that utilizes an estimation of the Lipschitz constant of the gradients in order to construct an adaptive learning rate per layer that can work on top of already existing optimizers, like SGD or Adam. A detailed experimental framework was used to prove the usefulness of the optimizer on three benchmark datasets. It showed that AdaLip improves the training performance and the convergence speed, but also made the training process more robust to the selection of the initial global learning rate.

Localizing Perturbations in Pressurized Water Reactors Using One-Dimensional Deep Convolutional Neural Networks

This work outlines an approach for localizing anomalies in nuclear reactor cores during their steady state operation, employing deep, one-dimensional, convolutional neural networks. Anomalies are characterized by the application of perturbation diagnostic techniques, based on the analysis of the so-called "neutron-noise" signals: that is, fluctuations of the neutron flux around the mean value observed in a steady-state power level. The proposed methodology is comprised of three steps: initially, certain reactor core perturbations scenarios are simulated in software, creating the respective perturbation datasets, which are specific to a given reactor geometry; then, the said datasets are used to train deep learning models that learn to identify and locate the given perturbations within the nuclear reactor core; lastly, the models are tested on actual plant measurements. The overall methodology is validated on hexagonal, pre-Konvoi, pressurized water, and VVER-1000 type nuclear reactors. The simulated data are generated by the FEMFFUSION code, which is extended in order to deal with the hexagonal geometry in the time and frequency domains. The examined perturbations are absorbers of variable strength, and the trained models are tested on actual plant data acquired by the in-core detectors of the Temelín VVER-1000 Power Plant in the Czech Republic. The whole approach is realized in the framework of Euratom's CORTEX project.

INTELLIGENT TECHNIQUES FOR ANOMALY DETECTION IN NUCLEAR REACTORS

The safe operation of nuclear power plants is highly dependent on the ability of quickly and accurately identifying possible anomalies and perturbations in the reactor. Operational defects are primarily diagnosed by detectors that capture changes in the neutron flux, placed at various points inside and outside of the core. Neutron flux signals are subsequently analyzed with signal processing techniques in an effort to be better described (have their higher-order characteristics uncovered, locate transient events, etc). To this end, the application of intelligent techniques may be extremely beneficial, as it may assist and extend the current level of analysis. Besides, the combination of signal processing methodologies and machine learning techniques in the framework of nuclear power plant data is an emerging topic that has yet to show its full potential. In this context, the current contribution attempts at introducing intelligent approaches and more specifically, deep learning techniques, in neutron flux signal analysis for the identification of perturbations and other anomalies in the reactor core that may affect its operational capabilities. The obtained results of an initial stage of analysis on neutron flux signals captured at pressurized water reactors are encouraging, underlying the robustness and the potential of the proposed approach.

A Simple Measure of Hepatocellular Carcinoma Burden Predicts Tumor Recurrence After Liver Transplantation: The Recurrent Hepatocellular Carcinoma-Initial, Maximum, Last Classification

Risk of recurrent hepatocellular carcinoma (rHCC) after liver transplantation (LT) depends on the pre-LT HCC burden, tumor behavior, and response to locoregional therapy (LRT). In December 2017, LT priority for HCC was expanded to select patients outside the Milan criteria who respond to LRT. Our aims were to develop a novel objective measure of pre-LT HCC burden (model of recurrent hepatocellular carcinoma-initial, maximum, last [RH-IML]), incorporating tumor behavior over time, and to apply RH-IML to model post-LT rHCC. Using United Network for Organ Sharing data from between 2002-2014 (development) and 2015-2017 (validation), we identified adult LT recipients with HCC and assessed pre-LT HCC tumor behavior and post-LT rHCC. For each patient, HCC burden was measured at 3 points on the waiting list: initial (I), maximum (M) total tumor diameter, and last (L) exception petition. HCC burden at these 3 points were classified as (A) <Milan, (B) Milan, (C) >Milan to University of California, San Francisco (UCSF), and (D) >UCSF, resulting in each patient having a 3-letter RH-IML designation. Of 16,558 recipients with HCC, 1233 (7%) had any post-LT rHCC. rHCC rates were highest in RH-IML group CCC (15%) and DDD (18%). When M and L tumor burdens did not exceed Milan (class B or A), rHCC was low (≤10%) as in AAA, ABA, ABB, BBA, BBB; rHCC was also low (≤10%) with successful downstaging when L was A (<Milan) and M tumor burden did not exceed I, as in BBA, CCA, and DDA. In conclusion, the RH-IML classification system is a simple summative measure of HCC burden that incorporates tumor behavior over time. RH-IML also estimates post-LT rHCC risk and is a useful tool for evaluating risk for rHCC post-LT.

Lifestyle, anthropometric, socio-demographic and perinatal correlates of early adolescence hypertension: The Healthy Growth Study

BACKGROUND AND AIMS

Various lifestyle, anthropometric, socio-demographic and perinatal characteristics have been separately associated with elevated blood pressure in children and adolescents. The aim of this study was to simultaneously evaluate all potential risk factors and to identify the most dominant correlates of early adolescence hypertension in a large group of school children 9-13 years old.

METHODS AND RESULTS

A cross-sectional study with 1444 schoolchildren 9-13 years old, having full data on lifestyle, anthropometric, socio-demographic and perinatal indices, as well as blood pressure measurements. Early adolescents born large for their gestational age (LGA) (OR, 95% C.I. 0.49 (0.25-0.97)), those with higher levels of moderate to vigorous physical activity (MVPA) (OR, 95% C.I. 0.71 (0.53-0.96)) and those of a higher socioeconomic status (SES) (OR, 95% C.I. 0.51 (0.33-0.79)), had lower risk of hypertension, compared with their counterparts with appropriate birth weight, low levels of PA and with low SES respectively, independently of the variables used in the multivariate model. On the other hand, overweight and obese early adolescents (OR, 95% C.I. 2.61 (1.88-3.62)), those with central obesity (OR, 95% C.I. 1.75 (1.12-2.73)) and those having a hypertensive father (OR, 95% C.I. 1.93 (1.20-3.12)) had higher risk of hypertension compared with normal weight early adolescents and those without a family history of hypertension.

CONCLUSIONS

Among the parameters examined, early adolescence abnormal body weight and central obesity, low PA, non LGA, low SES family and family history of hypertension were found to be independently associated with higher risk of hypertension. The identified correlates of early adolescence hypertension can be used by public health initiatives for early detection and management of this major public health problem, prioritizing early adolescents and families at the highest possible risk for hypertension.

Anti-apoptotic phenotypes of cholestan-3β,5α,6β-triol-resistant human cholangiocytes: characteristics contributing to the genesis of cholangiocarcinoma

The oxysterols cholestan-3β,5α,6β-triol (Triol) and 3-keto-cholest-4-ene (3K4) are increased in Opisthorchis viverrini-associated hamster cholangiocarcinoma and induce DNA damage and apoptosis via a mitochondria-dependent mechanism in MMNK-1 human cholangiocytes. Based on these observations, we hypothesized that chronic exposure of cholangiocytes to these pathogenic oxysterols may allow a growth advantage to a subset of these cells through selection for resistance to apoptosis, thereby contributing to cholangiocarcinogenesis. To test this hypothesis, we cultured MMNK-1 cells long-term in the presence of Triol. Alteration in survival and apoptotic factors of Triol-exposed cells were examined. Cells cultured long-term in the presence of Triol were resistant to H2O2-induced apoptosis, and demonstrated an increase in the phosphorylation of p38-α, CREB, ERK1/2 and c-Jun. Elevations in the ratio of Bcl-2/Bax and in the protein levels of anti-apoptotic factors including cIAP2, clusterin, and survivin were detected. These results show that long-term exposure of MNNK-1 cells to low doses of Triol selects for kinase-signaling molecules which regulate resistance to apoptosis and thereby enhance cell survival. Clonal expansion of such apoptosis-resistant cells may contribute to the genesis of cholangiocarcinoma.

Pharmacological cholesterol lowering reverses fibrotic NASH in obese, diabetic mice with metabolic syndrome

BACKGROUND & AIMS

We have recently showed that hyperinsulinemia promotes hepatic free cholesterol (FC) accumulation in obese, insulin-resistant Alms1 mutant (foz/foz) mice with NASH. Here we tested whether cholesterol-lowering drugs reduce stress-activated c-Jun N-terminal kinase (JNK) activation, hepatocyte injury/apoptosis, inflammation, and fibrosis in this metabolic syndrome NASH model.

METHODS

Female foz/foz and WT mice were fed HF (0.2% cholesterol) 16 weeks, before adding ezetimibe (5 mg/kg), atorvastatin (20 mg/kg), or both to diet, another 8 weeks. Hepatic lipidomic analysis, ALT, liver histology, Sirius Red morphometry, hepatic mRNA and protein expression and immunohistochemistry (IHC) for apoptosis (M30), macrophages (F4/80), and polymorphs (myeloperoxidase) were determined.

RESULTS

In mice with NASH, ezetimibe/atorvastatin combination normalized hepatic FC but did not alter saturated free fatty acids (FFA) and had minimal effects on other lipids; ezetimibe and atorvastatin had similar but less profound effects. Pharmacological lowering of FC abolished JNK activation, improved serum ALT, apoptosis, liver inflammation/NAFLD activity score, designation as "NASH", macrophage chemotactic protein-1 expression, reduced macrophage and polymorph populations, and liver fibrosis.

CONCLUSIONS

Cholesterol lowering with ezetimibe/atorvastatin combination reverses hepatic FC but not saturated FFA accumulation. This dampens JNK activation, ALT release, hepatocyte apoptosis, and inflammatory recruitment, with reversal of steatohepatitis pathology and liver fibrosis. Ezetimibe/statin combination is a potent, mechanism-based treatment that could reverse NASH and liver fibrosis.

Hepatic free cholesterol accumulates in obese, diabetic mice and causes nonalcoholic steatohepatitis

BACKGROUND & AIMS

Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH.

METHODS

Alms1 mutant (foz/foz) and wild-type NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice.

RESULTS

Hepatic cholesterol accumulation was attributed to up-regulation of low-density lipoprotein receptor via activation of sterol regulatory element binding protein 2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and low-density lipoprotein receptor and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol levels exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis.

CONCLUSIONS

In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH.

Measuring the Impact of an ERP Project at SMEs

This article analyses and tests a novel framework for the evaluation of an ERP project. The framework incorporates specific performance measures, which are linked to a previously developed model, (the ‘six-imperatives’ framework) and are relevant to ERP implementation Two case studies illustrate the use of the framework in two Greek companies aiming to measure, in practical terms, the impact of the ERP project on their operations. The main results indicate that the “six-imperatives” provide a comprehensive methodology based on the profound exploration and understanding of specific business processes and objectives that should be met in order to assess an ERP project.

[Acquired Gitelman syndrome associated with Sjögren's syndrome and scleroderma]

Tubulopathy can complicate autoimmune diseases. It is usually a distal tubular acidosis, but Fanconi syndrome or Bartter syndrome has been exceptionally reported. We report a case of acquired Gitelman syndrome in a 32-year-old male who also presented diffuse scleroderma autoimmune thyroiditis, and Sjögren's syndrome. Only three cases of Sjögren syndrome associated with Gitelman syndrome have been previously reported in literature. The absence of other cases in the family and absence of mutation SLC12A3 emphasise the relation between autoimmune disease and this tubulopathy.

Survival after orthotopic liver transplantation: the impact of antibody against hepatitis B core antigen in the donor

Liver transplantation using grafts from donors with antibody against hepatitis B core antigen (anti-HBc) increases the recipients' risk of developing hepatitis B virus (HBV) infection post-transplantation. Our aim was to assess whether using such grafts was associated with reduced posttransplantation survival and whether this association depended on recipients' prior exposure to HBV on the basis of their pretransplantation serological patterns. Data were derived from the United Network for Organ Sharing on adult, cadaveric, first-time liver transplants performed between 1994 and 2006. Among recipients who did not have HBV infection before transplantation, those with anti-HBc-positive donors had significantly worse unadjusted posttransplantation patient survival than recipients with anti-HBc-negative donors [hazard ratio, 1.35; 95% confidence interval (CI), 1.21-1.50]. However, after adjustments for other predictors of posttransplantation survival, including donor age, donor race, and recipient underlying liver diseases, patient survival was not significantly different between the 2 groups (hazard ratio, 1.09; 95% CI, 0.97-1.24). Among recipients without antibody against hepatitis B surface antigen (anti-HBs), use of anti-HBc-positive donor grafts was associated with a trend toward worse survival (adjusted hazard ratio, 1.18; 95% CI, 0.95-1.46), whereas no such trend was observed among recipients positive for anti-HBs. In conclusion, in patients without HBV infection before transplantation, using anti-HBc-positive donors was not independently associated with worse posttransplantation survival. Matching these donors to recipients with anti-HBs pre-transplantation may be especially safe.

Terlipressin for acute esophageal variceal hemorrhage

BACKGROUND

Terlipressin (triglycyl lysine vasopressin) is a synthetic analogue of vasopressin, which has been used in the treatment of acute variceal hemorrhage. In contrast to vasopressin, terlipressin can be administered as intermittent injections instead of continuous intravenous infusion and it has a safer adverse reactions profile. However, its effectiveness remains uncertain.

OBJECTIVES

To determine if treatment with terlipressin improves outcome in acute esophageal variceal hemorrhage and is safe.

SEARCH STRATEGY

Randomized clinical trials were identified by searching the following databases: MEDLINE, EMBASE, the Cochrane Controlled Trials Register, the Cochrane Hepato-Biliary Group Controlled Trials Register, Biosis, and Current Contents. The bibliographies of identified publications were checked. Experts in the field and the manufacturers of terlipressin were contacted.

SELECTION CRITERIA

All randomized clinical trials which compared terlipressin with: (a) placebo or no treatment, (b) balloon tamponade, (c) endoscopic treatment, (d) octreotide, (e) somatostatin and (f) vasopressin, in the setting of acute variceal hemorrhage.

DATA COLLECTION AND ANALYSIS

Eligibility, trial quality assessment and data extraction were done independently by two reviewers. The primary outcome measure was mortality. Secondary outcomes were failure of initial hemostasis, rebleeding, procedures required for uncontrolled bleeding or rebleeding, transfusion requirements and length of hospitalization.

MAIN RESULTS

Twenty studies were identified for all the comparison groups, involving 1609 patients. There were seven studies (with 443 patients) comparing terlipressin to placebo, five of which were considered to be high quality studies based on the Jadad scale. The meta-analysis indicates that terlipressin was associated with a statistically significant reduction in all cause mortality compared to placebo (relative risk 0.66, 95% confidence interval 0.49 to 0.88). Three studies (with 302 patients) were identified comparing terlipressin to somatostatin, two of which were high quality studies; only one high quality study (219 patients) comparing terlipressin to endoscopic treatment was identified. Within the limited power provided by these small numbers of patients, no statistically significant difference was demonstrated between terlipressin and either somatostatin or endoscopic treatment in any of the outcomes. For the remaining comparison groups (terlipressin versus balloon tamponade, terlipressin versus octreotide and terlipressin versus vasopressin) only small, low quality studies were identified and no difference was demonstrated in any of the major outcomes. There was no difference between the terlipressin group and any of the comparison groups in the number of adverse events that caused death or withdrawal of medication.

REVIEWER'S CONCLUSIONS

On the basis of a 34% relative risk reduction in mortality, terlipressin should be considered to be effective in the treatment of acute variceal hemorrhage. Further, since no other vasoactive agent has been shown to reduce mortality in single studies or meta-analyses, terlipressin might be the vasoactive agent of choice in acute variceal bleeding.

Duplex sonography in detection of renal artery stenosis: a simplified approach using new parameters

A case report illustrating a new investigation for detecting renal artery stenosis (RAS) is reported. Colour Doppler ultrasound evaluation of the readily accessible intrarenal arteries is a fast and accurate technique. Acceleration time and acceleration are the Doppler parameters used for measuring systolic upstroke on the waveforms obtained. Prolonged acceleration time (> or = 0.07s) and diminished acceleration (< or = 3 m/s2) indicate haemodynamically significant stenosis. Intrarenal Doppler ultrasound should provide a safe noninvasive screening examination for the detection of RAS.