In-situ Blockage Monitoring of Sensing Line

Aijaz Ahmed Mangi,Syed Salman Shahid,Sikander Hayat Mirza 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.1

A reactor vessel level monitoring system measures the water level in a reactor duringnormal operation and abnormal conditions. A drop in the water level can expose nuclearfuel, which may lead to fuel meltdown and radiation spread in accident conditions. A levelmonitoring system mainly consists of a sensing line and pressure transmitter. Over aperiod of time boron sediments or other impurities can clog the line which may degradethe accuracy of the monitoring system. The aim of this study is to determine blockage in asensing line using the energy of the composite signal. An equivalent Pi circuit model isused to simulate blockages in the sensing line and the system's response is examinedunder different blockage levels. Composite signals obtained from the model and plant'sunblocked and blocked channels are decomposed into six levels of details and approximationsusing a wavelet filter bank. The percentage of energy is calculated at each level forapproximations. It is observed that the percentage of energy reduces as the blockage levelin the sensing line increases. The results of the model and operational data are wellcorrelated. Thus, in our opinion variation in the energy levels of approximations can beused as an index to determine the presence and degree of blockage in a sensing line.

In-situ Blockage Monitoring of Sensing Line

Mangi, Aijaz Ahmed,Shahid, Syed Salman,Mirza, Sikander Hayat Korean Nuclear Society 2016 Nuclear Engineering and Technology Vol.48 No.1

A reactor vessel level monitoring system measures the water level in a reactor during normal operation and abnormal conditions. A drop in the water level can expose nuclear fuel, which may lead to fuel meltdown and radiation spread in accident conditions. A level monitoring system mainly consists of a sensing line and pressure transmitter. Over a period of time boron sediments or other impurities can clog the line which may degrade the accuracy of the monitoring system. The aim of this study is to determine blockage in a sensing line using the energy of the composite signal. An equivalent Pi circuit model is used to simulate blockages in the sensing line and the system's response is examined under different blockage levels. Composite signals obtained from the model and plant's unblocked and blocked channels are decomposed into six levels of details and approximations using a wavelet filter bank. The percentage of energy is calculated at each level for approximations. It is observed that the percentage of energy reduces as the blockage level in the sensing line increases. The results of the model and operational data are well correlated. Thus, in our opinion variation in the energy levels of approximations can be used as an index to determine the presence and degree of blockage in a sensing line.

An investigation on the influence of filler loading and compatibilizer on the properties of polypropylene/marble sludge composites

Khalil Ahmed,Nudrat Zahid Raza,Farzana Habib,Muhammad Aijaz,Muhammad Hayat Afridi 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6

In this article, polypropylene reinforced marble sludge (PP/MS) was prepared, and the effects of MS loading and polypropylene-g-maliec anhydride (PP-g-MAH) as compatibilizer on density, melt flow index (MFI), and mechanical properties of PP/MS composite were investigated. Our studies show that tensile strength, flexural strength and tensile modulus increased with increasing the MS loading but tensile strength increased till 30 pph of MS further addition of MS in PP composites decreased the strength. The % elongation at break and Izod Impact Strength decreased with increasing of MS loading. Studies revealed that PP/MS composites containing PP-g-MAH enhance the properties compared to without compatibilizer.

Causes and risk profiles of mortality among individuals with nonalcoholic fatty liver disease

Peter Konyn,Aijaz Ahmed,Donghee Kim 대한간학회 2023 Clinical and Molecular Hepatology(대한간학회지) Vol.29 No.-

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the United States and worldwide. Though nonalcoholic fatty liver per se may not be independently associated with an increased risk for all-cause mortality, it is associated with a number of harmful metabolic risk factors, such as type 2 diabetes mellitus, hyperlipidemia, obesity, a sedentary lifestyle, and an unhealthy diet. The fibrosis stage is a predictor of all-cause mortality in NAFLD. Mortality in individuals with NAFLD has been steadily increasing, and the most common cause-specific mortality for NAFLD is cardiovascular disease, followed by extra-hepatic cancer, liver-related mortality, and diabetes. High-risk profiles for mortality in NAFLD include PNPLA3 I148M polymorphism, low thyroid function and hypothyroidism, and sarcopenia. Achieving weight loss through adherence to a high-quality diet and sufficient physical activity is the most important predictor of improvement in NAFLD severity and the benefit of survival. Given the increasing health burden of NAFLD, future studies with more long-term mortality data may demonstrate an independent association between NAFLD and mortality.

Recent Epidemiology of Nonalcoholic Fatty Liver Disease

( Soumya Murag ),( Aijaz Ahmed ),( Donghee Kim ) 대한소화기학회 2021 Gut and Liver Vol.15 No.2

The ongoing obesity epidemic and the increasing recognition of metabolic syndrome have contributed to the growing prevalence of nonalcoholic fatty liver disease (NAFLD), the most common form of liver disease worldwide. It is imperative to understand the incidence and prevalence of NAFLD as it is associated with a profound economic burden of hospitalizations, including the shifting trends in liver transplantation. The long-term cumulative healthcare cost of NAFLD patients has been shown to be 80% higher than that of non-NAFLD patients. We explore diagnostic challenges in identifying those with NAFLD who have a higher predilection to progress to end-stage liver disease. We aim to assess all-cause and cause-specific mortality as it relates to NAFLD. (Gut Liver 2021;15:206-216)

The current trends in the health burden of primary liver cancer across the globe

Peter Konyn,Aijaz Ahmed,Donghee Kim 대한간학회 2023 Clinical and Molecular Hepatology(대한간학회지) Vol.29 No.2

Extrahepatic Manifestations of Nonalcoholic Fatty Liver Disease

( Andrew A. Li ),( Aijaz Ahmed ),( Donghee Kim ) 대한간학회 2020 Gut and Liver Vol.14 No.2

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and encompasses a spectrum of pathology from simple steatosis to inflammation and significant fibrosis that leads to cirrhosis. NAFLD and its comorbid conditions extend well beyond the liver. It is a multisystemic clinical disease entity with extrahepatic manifestations such as cardiovascular disease, type 2 diabetes, chronic kidney disease, hypothyroidism, polycystic ovarian syndrome, and psoriasis. Indeed, the most common causes of mortality in subjects with NAFLD are cardiovascular disease, followed by malignancies and then liver-related complications as a distant third. This review focuses on several of the key extrahepatic manifestations of NAFLD and areas for future investigation. Clinicians should learn to screen and initiate treatment for these extrahepatic manifestations in a prompt and timely fashion before they progress to end-organ damage. (Gut Liver 2020;14:168-178)

Evaluation and management of extrahepatic manifestations of nonalcoholic fatty liver disease

( Karn Wijarnpreecha ),( Elizabeth S. Aby ),( Aijaz Ahmed ),( Donghee Kim ) 대한간학회 2021 Clinical and Molecular Hepatology(대한간학회지) Vol.27 No.2

Nonalcoholic fatty liver disease (NAFLD) is a multisystemic disease and a rapidly growing cause of chronic liver disease in children and adults worldwide. Diagnosis and management of extrahepatic manifestations of NAFLD, including cardiovascular disease (CVD), type 2 diabetes mellitus, metabolic syndrome, chronic kidney disease, obstructive sleep apnea, polycystic ovarian syndrome, hypothyroidism, psoriasis, and extrahepatic malignancy are crucial for the treatment of patients with NAFLD. The leading cause of death in NAFLD is primarily from CVD, followed by liver-related mortality, extrahepatic cancer, liver cancer, and diabetes-related mortality. Therefore, clinicians need to identify high-risk patients earlier in the disease course and be aware of the extrahepatic manifestations of NAFLD to improve liver disease outcomes. In this review, we focus on the monitoring and management of the extrahepatic manifestations of NAFLD. (Clin Mol Hepatol 2021;27:221-235)

Subclinical Hypothyroidism and Low-Normal Thyroid Function Are Associated With Nonalcoholic Steatohepatitis and Fibrosis

Kim, Donghee,Kim, Won,Joo, Sae Kyung,Bae, Jeong Mo,Kim, Jung Ho,Ahmed, Aijaz Elsevier 2018 Clinical gastroenterology and hepatology Vol.16 No.1

<P><B>Background & Aims</B></P> <P>Variations in level of thyroid-stimulating hormone (TSH) within the reference range of thyroid hormone could have negative health effects. We evaluated the effect of plasma TSH levels within the euthyroid range on the severity of histological damage associated with nonalcoholic fatty liver disease (NAFLD).</P> <P><B>Methods</B></P> <P>We performed a cross-sectional study of 425 subjects with biopsy-proven NAFLD (mean age, 53 years; 52% male) who participated in the Boramae NAFLD study from January 2013 to January 2017. Each subject underwent an anthropometric assessment and laboratory and clinical evaluations. Of the subjects, 282 were assigned to a strict-normal thyroid function group (plasma level of TSH, 0.4 to 2.5 mIU/L). Patients with low thyroid function were assigned to groups of subclinical hypothyroidism (plasma level of TSH above 4.5 mIU/L with a normal thyroid hormone level; n = 59) or low-normal thyroid function (higher plasma TSH level [2.5 to 4.5 mIU/L] with a normal thyroid hormone level; n = 84). Multivariate logistic regression analysis was used to identify factors independently associated with nonalcoholic steatohepatitis (NASH) and advanced fibrosis.</P> <P><B>Results</B></P> <P>NASH and advanced fibrosis were found in higher percentages of subjects with low thyroid function vs strict-normal thyroid function (52.4% vs 37.2% for NASH and 21.0% vs 10.6% for advanced fibrosis; <I>P</I> < .01). Among subjects with low thyroid function, a higher proportion of patients with subclinical hypothyroidism had NASH and associated advanced fibrosis vs patients with low-normal thyroid function (57.6% vs 48.8% for NASH and 25.4% vs 17.9% for advanced fibrosis; <I>P</I> < .01). Subjects with low thyroid function had more extensive hepatic steatosis with greater severity of balloon degeneration and fibrosis. In multivariate analyses, low thyroid function was significantly associated with NASH (odds ratio, 1.61; 95% CI, 1.04–2.50; <I>P</I> = .035) and advanced fibrosis (odds ratio, 2.23; 95% CI, 1.18–4.23; <I>P</I> = .014). Risks of NASH and advanced fibrosis increased significantly with plasma concentration of TSH (<I>P</I>trend <.05 for each).</P> <P><B>Conclusions</B></P> <P>Subclinical hypothyroidism and low-normal thyroid function are independent predictors of NASH and advanced fibrosis, confirming the relationship between these diseases. ClinicalTrials.gov, Number: NCT02206841.</P>

Subclinical Hypothyroidism and Low-Normal Thyroid Function Are Associated With Nonalcoholic Steatohepatitis and Fibrosis

( Dong Seok Lee ),( Won Kim ),( Sae Kyung Joo ),( Jeong Mo Bae ),( Jung Ho Kim ),( Aijaz Ahmed ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Variations in level of thyroid-stimulating hormone (TSH) within the reference range of thyroid hormone could have negative health effects. We evaluated the effect of plasma TSH levels within the euthyroid range on the severity of histological damage associated with nonalcoholic fatty liver disease (NAFLD). Methods: We performed a cross-sectional study of 425 subjects with biopsy-proven NAFLD (mean age, 53 years; 52% male) who participated in the Boramae NAFLD study from January 2013 to January 2017. Each subject underwent an anthropometric assessment and laboratory and clinical evaluations. Of the subjects, 282 were assigned to a strict-normal thyroid function group (plasma level of TSH, 0.4 to 2.5 mIU/L). Patients with low thyroid function were assigned to groups of subclinical hypothyroidism (plasma level of TSH above 4.5 mIU/L with a normal thyroid hormone level; n [59) or low-normal thyroid function (higher plasma TSH level [2.5 to 4.5 mIU/L] with a normal thyroid hormone level; n [ 84). Multivariate logistic regression analysis was used to identify factors independently associated with nonalcoholic steatohepatitis (NASH) and advanced fibrosis. Results: NASH and advanced fibrosis were found in higher percentages of subjects with low thyroid function vs strict-normal thyroid function (52.4% vs 37.2% for NASH and 21.0% vs 10.6% for advanced fibrosis; P<.01). Among subjects with low thyroid function, a higher proportion of patients with subclinical hypothyroidism had NASH and associated advanced fibrosis vs patients with low-normal thyroid function (57.6% vs 48.8% for NASH and 25.4% vs 17.9% for advanced fibrosis; P<.01). Subjects with low thyroid function had more extensive hepatic steatosis with greater severity of balloon degeneration and fibrosis. In multivariate analyses, low thyroid function was significantly associated with NASH (odds ratio, 1.61; 95% CI, 1.04-2.50; P [ .035) and advanced fibrosis (odds ratio, 2.23; 95% CI, 1.18-4.23; P [ .014). Risks of NASH and advanced fibrosis increased significantly with plasma concentration of TSH (Ptrend <.05 for each). Conclusions: Subclinical hypothyroidism and low-normal thyroid function are independent predictors of NASH and advanced fibrosis, confirming the relationship between these diseases. ClinicalTrials. gov, Number: NCT02206841.