Computer Vision Based Structural Identification Framework for Bridge Health Mornitoring

The objective of this dissertation is to develop a comprehensive Structural Identification (St-Id) framework with damage for bridge type structures by using cameras and computer vision technologies. The traditional St-Id frameworks rely on using conventional sensors. In this study, the collected input and output data employed in the St-Id system are acquired by series of vision-based measurements. The following novelties are proposed, developed and demonstrated in this project: a) vehicle load (input) modeling using computer vision, b) bridge response (output) using full non-contact approach using video/image processing, c) image-based structural identification using input-output measurements and new damage indicators. The input (loading) data due vehicles such as vehicle weights and vehicle locations on the bridges, are estimated by employing computer vision algorithms (detection, classification, and localization of objects) based on the video images of vehicles. Meanwhile, the output data as structural displacements are also obtained by defining and tracking image key-points of measurement locations. Subsequently, the input and output data sets are analyzed to construct novel types of damage indicators, named Unit Influence Surface (UIS). Finally, the new damage detection and localization framework is introduced that does not require a network of sensors, but much less number of sensors. The main research significance is the first time development of algorithms that transform the measured video images into a form that is highly damage-sensitive/change-sensitive for bridge assessment within the context of Structural Identification with input and output characterization. The study exploits the unique attributes of computer vision systems, where the signal is continuous in space. This requires new adaptations and transformations that can handle computer vision data/signals for structural engineering applications. This research will significantly advance current sensor-based structural health monitoring with computer-vision techniques, leading to practical applications for damage detection of complex structures with a novel approach. By using computer vision algorithms and cameras as special sensors for structural health monitoring, this study proposes an advance approach in bridge monitoring through which certain type of data that could not be collected by conventional sensors such as vehicle loads and location, can be obtained practically and accurately

Intravenous Acetaminophen Hepatotoxicity in a Liver Transplant Patient

INTRODUCTION: Eighty to ninety percent of APAP is metabolized by glucuronidation and sulfation and excreted in urine. The remaining 5-10% of APAP is metabolized by CYP450/CYP2E into N-acetyl-p-benzoquinone imine (NAPQI), the toxic metabolite responsible for APAP hepatotoxicity.3 NAPQI is inactivated when conjugated to tripeptide glutathione. During APAP overdose, excessive quantities of NAPQI and depleted glutathione stores lead to hepatotoxicity.3 There exists only two case reports on hepatotoxicity associated with therapeutic doses of IV APAP in post-operative patients with native livers, however, one was confounded by post-operative shock liver.4,5 There is no validated nomogram to guide treatment of IV APAP overdose or toxicity. NAC therapy remains the mainstay for PO APAP overdose. CASE REPORT: A 69 year old male with a past medical history of secondary biliary liver cirrhosis status post orthotopic liver transplantation in 2006, Hepatocellular carcinoma of the explanted liver, splenic artery aneurysm status post splenectomy and newly diagnosed prostate adenocarcinoma was admitted to the Urology service for planned robotic-assisted prostatectomy. Eighteen days prior to presentation, the patient was medically cleared by Transplant Hepatology for prostatectomy. He was noted to have a normal functioning hepatic graft and advised to continue taking tacrolimus 0.5 mg twice daily. At that time, aminotransferase (AST) was 23 IU/L, alanine aminotransferase (ALT) 24 IU/L, total bilirubin (TBili) 1.4 mg/dL, and international normalized ratio (INR) 1.0. He underwent uncomplicated robotic-assisted prostatectomy, requiring no fluid resuscitation, vasopressor support or blood products. Post-operatively, vital signs remained normal with no episodes of hypotension. Physical exam was notable for mild tenderness to palpation around the laparoscopic incision sites. He was started on a clear liquid diet and IV APAP 1000 mg every 6 hours for 36 hours, followed by PO APAP 650 mg every 6 hours for post-operative pain. On post-operative day 1, AST was 2275 IU/L, ALT 2521 IU/L, TBili 1.3 mg/dL, and INR 1.4. On post-operative day 2, AST was 2751 IU/L, ALT 3447 IU/L, TBili 1.9 mg/dL and INR 1.5 (Figure 1). The patient developed a diffuse, pruritic maculopapular rash around his torso and bilateral upper arms, unrelieved by oral diphenhydramine. All orders for acetaminophen were stopped. Liver Doppler ultrasound was normal. By this time, the patient had received 5000 mg of IV APAP and 650 mg of PO APAP total. A serum acetaminophen level was drawn 10 hours after the last IV APAP dose and noted to be \u3c 15 ug/mL. Hepatology was consulted. The patient reported consuming daily herbal supplements for the past 14 months, including saw palmetto, pygeum, cranberry extract, pumpkin seed extract and beta-sitosterol. He stopped taking the herbal supplements 7 days prior to the prostatectomy. He denied alcohol use and reported minimal nausea, but no vomiting. His average daily intake was 3.5 liters. Work up for infectious etiologies was negative. The patient was started on IV NAC, with a loading dose of 150 mg/kg followed by a maintenance dose of 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours. Within 18 hours, AST was 1350 IU/L, ALT 2836 IU/L, and INR 1.5. TBili increased to 2.4 mg/dL. Following completion of IV NAC therapy, AST was 986 IU/L, ALT 2340 IU/L, TBili 1.9 mg/dL, and INR 1.4. His macular papular rash resolved during IV NAC therapy. The patient was discharged home on post-operative day 4. Labs during his outpatient Hepatology follow-up appointment 4 days after discharge were AST 62 IU/L, ALT 426 IU/L, TBili 1.3 mg/dL, and INR 1.1. DISCUSSION: This is the first case of acute liver toxicity in a post-OLT patient who received therapeutic doses of IV APAP subsequently responded to IV NAC therapy. The patient\u27s AST, ALT, TBili and INR were normal prior to IV APAP exposure. Elevations in AST, ALT, TBili, and INR improved after IV APAP was discontinued and IV NAC initiated. A serum APAP level drawn 10 hours after the last IV APAP administration was \u3c 15 ug/mL, consistent with therapeutic dosage. There was no evidence of hypotension or APAP overdose in the electronic medical records. All other etiologies for acute liver toxicity were ruled out, including shock liver, infection and vascular compromise. Risk factors that have been shown to increase the risk of hepatotoxicity in APAP overdose patients include malnutrition, eating disorders, AIDS, alcoholism, antiepileptic medications, and tuberculosis medications.6 Our patient did not have any of these risk factors. Although he experienced nausea post-operatively, daily total intake was adequate and there were no periods of fasting or malnutrition. It is unlikely the patient\u27s hepatotoxicity was due to herbal drug induced liver injury or herbal-drug interactions with IV APAP. Case reports exist on saw palmetto associated cholestatic hepatotoxicity.7 However, prospective trials have found little evidence of liver injury linked to saw palmetto.8 There was no history of hepatotoxicity during the 14 months that the patient consumed saw palmetto and he ceased saw palmetto consumption 7 days prior to admission. Online Pubmed literature searches on hepatotoxicity due to pygeum, cranberry extract, pumpkin seed extract or beta-sitosterol did not yield results. The patient\u27s transplant liver may have been predisposed to IV APAP toxicity, even at therapeutic doses. It is possible APAP metabolism is altered in transplant livers compared to native livers. A study on 13 liver transplant patients concluded APAP metabolism was transiently altered in orthotopic livers following liver transplantation, resulting in enhanced NAPQI production.9 Liver Transplant Centers in the Scientific Registry of Transplant Recipients have issued post-OLT guidebooks for patients, recommending no more than 1500 mg to 2000 mg of PO APAP daily, lower than the daily maximum limit of 4000 mg.10,11,12 Furthermore, studies show decreased glutathione levels in transplant livers after undergoing pre-transplant cold storage preservation and post-transplant reperfusion. It is possible transplant livers carry less glutathione stores, rendering them more susceptible to hepatotoxicity from NAPQI concentrations that a native liver would tolerate.13 Further studies on what is considered safe, therapeutic IV APAP dosing in post-OLT patients is needed to prevent hepatotoxicity in this patient population

Household's willingness-to-pay estimation for safe drinking water: a case study in Vietnam

2013 Spring.Includes bibliographical references.This thesis explores consumer behavior of households for drinking water by surveying and analyzing 235 households (HHs) in Hanoi and Hai Duong in the North of Vietnam, and Ho Chi Minh in South of Vietnam. Two classical methods have been employed, Contingent valuation method (CVM) and averting behavior method (ABM). Binary logit regression can help to identify internal and external factors influencing the decision of whether or not to pay for clean drinking water. In addition, the linear regression method allows to explore and to quantify the magnitude of relationship between the dependent variable and independent variables. Generally, about half of the households surveyed are willing to pay for better drinking water. Most of them are HHs living in two major cities, Hanoi and Ho Chi Minh City. On average for all of the sampled households, the value of willingness-to-pay makes up small percentage of household income, just 0.247% of total household income. The decision to pay for water depends on both internal factors: the level of education and awareness, as well as external factors: living conditions and existing water source. For those households that are willing to pay to get clean water services, income, and current status of water resources are strong variables. In addition, those households that are actively looking for information and learning related to water often pay a fee for water use. Different measures are practiced by HH's to prevent diseases caused by possible polluted drinking water. Of the five averting activities, boiling water is HHs' priority in rural areas due to low cost while buying bottled water is HH's choice in the city because of the convenience. Young people tend to use bottled water more than old people. Using a water filter increases amount of money they would be willing to pay for clean water, while income and habitat of using drinking water are also strong factors in determining willingness to pay a higher monthly water bill. This survey has compared two values: the value of WTP and the cost of averting expenditure (CAE). My results showed that WTP is not always greater than CAE. Empirical results have policy implications on drinking water price strategies and drinking water related projects investment in Vietnam. Policy-makers or planners should consider income, gender, level of education, existing water sources, lifestyles, and locale when making drinking water price strategies and water related investment

Coupling of Active Motion and Advection Shapes Intracellular Cargo Transport

Intracellular cargo transport can arise from passive diffusion, active motor-driven transport along cytoskeletal filament networks, and passive advection by fluid flows entrained by such motor/cargo motion. Active and advective transport are thus intrinsically coupled as related, yet different representations of the same underlying network structure. A reaction-advection-diffusion system is used here to show that this coupling affects the transport and localization of a passive tracer in a confined geometry. For sufficiently low diffusion, cargo localization to a target zone is optimized either by low reaction kinetics and decoupling of bound and unbound states, or by a mostly disordered cytoskeletal network with only weak directional bias. These generic results may help to rationalize subtle features of cytoskeletal networks, for example as observed for microtubules in fly oocytes.Comment: revtex, 5 pages, 5 figures, to appear in PRL (http://prl.aps.org/

The Accuracy of Endodontic Length Measurement Using Cone-beam Computed Tomography in Comparison with Electronic Apex Locators

Introduction: The aim of this in vitro study was to evaluate the accuracy of cone-beam computed tomography (CBCT) and two electronic apex locators (EALs) when measuring the actual length of root canals. Methods and Materials: One hundred and eighty four root canals in 135 extracted anterior and posterior permanent teeth were studied. Root canal curvatures were analyzed on CBCT images, and root canals with curvatures less than 70º were chosen. Root canal length measurements were performed using CBCT, ProPex Pixi, E-Pex Pro, and the actual length (AL). The percentages of the measurements in the range of ±0.5 mm to the AL were compared using Fisher’s Exact test. The ICC indices and Bland-Altman plots were used to display the agreement of three devices with the AL measurements. The statistical significance was set at P<0.05. Results: The accuracies of E-Pex Pro and ProPex Pixi (87.5% and 82.6%, respectively) were better than that of CBCT (71.7%) (P<0.05). Conclusion: This in vitro study showed that although the accuracies of the two EALs were at high level, there was no device that had an agreement with the actual root canal length measurementKeywords:Cone-beam Computed Tomography; Electronic Apex Locator; Endodontics; Root Canal Length; Root Canal Therapy 

Pesticide poisoning of farm workers : implications of blood test results from Vietnam

In this paper, the authors have assessed the incidence and determinants of pesticide poisoning among rice farmers in Vietnam's Mekong Delta. Blood cholinesterase tests suggest that the incidence of poisoning from exposure to organophosphates and carbamates is quite high in Vietnam. Using the medical test results as benchmarks, the authors find that farmers'self-reported symptoms have very weak associations with actual poisoning. Regression analysis of blood tests reveals a lower incidence of poisoning for farmers who avoid the most toxic pesticides and use protective items. The authors also find very large provincial differences in poisoning incidence after they control for individual factors. The results highlight the potential importance of negative externalities, and suggest that future research on pesticide-related damage should include information on local water, air, and soil contamination.Pest Management,Crops&Crop Management Systems,Sustainable Land and Crop Management,Health Monitoring&Evaluation,Agricultural Research

DETERMINANTS OF THE INTENTION TO USE LOAN SHARKS OF STUDENTS: EMPIRICAL EVIDENCES FROM VIETNAMESE UNIVERSITIES

Based on the development of the Unified Theory of Acceptance and Use of Technology model (UTAUT), the authors measured the intention to use loan sharks for students in Vietnamese universities. The research utilizes both quantitative and qualitative methods with the primary data collected from students in Vietnamese universities. The results demonstrate that three main variables significantly impact on intention to use loan sharks, namely "Social Influence," "Financial Literacy," and "Expectancy Effort." In particular, the authors added the "Financial Literacy" element through the results of in-depth interviews. Besides, "Gender" and "Academic Year" also affect the relationship between three main variables and the intention to use loan sharks. Based on the research results, the authors propose several specific policy implications for authorities to eliminate loan sharks through social media and promote financial literacy in universities

Về khả năng ứng dụng của hệ xử lý thông tin 3D và nguyên lý bán dẫn giá trị trong tìm kiếm giải pháp cho vấn đề ô nhiễm môi trường và biến đổi khí hậu ở Việt Nam

Giải quyết biến đổi khí hậu và ô nhiễm môi trường đang và sẽ là thách thức lớn của nhân loại trong thế kỷ 21. Con người không còn nhiều thời gian để sửa chữa, phục hồi đưa hệ sinh thái môi trường (tự nhiên) trở về trạng thái an toàn. Trong khi các nỗ lực trong thời gian qua chưa thực sự hiệu quả thì COP26 mở ra cơ hội lớn để nhân loại tiến gần đến mục tiêu kiềm chế nhiệt độ của trái đất không vượt quá 1.5 độ C. Mặc dù Việt Nam cùng với 146 quốc gia trên thế giới đã có cam kết mạnh mẽ nhất trong việc giảm phát thải vào năm 2050, tuy nhiên việc cụ thể hóa cam kết thông qua các giải pháp sáng tạo là rất quan trọng. Sử dụng (áp dụng, vận dụng) hệ sáng tạo 3D và nguyên lý bán dẫn giá trị, tác giả đề xuất hệ sinh thái “giải pháp trụ cột” cần thực hiện gồm có tăng cường thông tin, truyền thông, nghiên cứu khoa học về môi trường (biến đổi khí hậu, ô nhiễm môi trường...); xây dựng, chuyển đổi và nâng cao văn hóa và môi trường; đẩy mạnh phát triển kinh tế gia tăng phúc lợi; xây dựng (chuyển đổi) lớp doanh nhân có văn hóa, trách nhiệm môi trường; tăng cường mở rộng sự hợp tác quốc tế về mọi mặt đặc biệt là trong lĩnh vực kinh tế, truyền thông và khoa học; và thực thi các giải pháp nêu trên một cách kỷ luật

How do we perceive serendipity?

In order to set a ground for the new hypotheses, theory, and conceptual framework of serendipity, the current chapter aims to review the research landscapes, definitions, types, influential factors, and processes of serendipity. First, bibliometric analyses of 2982 documents retrieved from the Web of Science database were employed to examine the intellectual and conceptual structures in the research field of serendipity. Three major research lines are found: 1) information-seeking behaviors, 2) serendipity in business and sciences, and 3) serendipity in recommender systems. Then, a narrative review of the most notable documents and studies was done to overview the serendipity’s definitions, types, influential factors, and processes. Based on the review, we stipulate the literature gap in which the newly proposed hypotheses, theory, and conceptual framework will fit in