A FRF-based algorithm for damage detection using experimentally collected data

Garcia-Palencia, Antonio,Santini-Bell, Erin,Gul, Mustafa,Catbas, Necati Techno-Press 2015 Structural monitoring and maintenance Vol.2 No.4

Automated damage detection through Structural Health Monitoring (SHM) techniques has become an active area of research in the bridge engineering community but widespread implementation on in-service infrastructure still presents some challenges. In the meantime, visual inspection remains as the most common method for condition assessment even though collected information is highly subjective and certain types of damage can be overlooked by the inspector. In this article, a Frequency Response Functions-based model updating algorithm is evaluated using experimentally collected data from the University of Central Florida (UCF)-Benchmark Structure. A protocol for measurement selection and a regularization technique are presented in this work in order to provide the most well-conditioned model updating scenario for the target structure. The proposed technique is composed of two main stages. First, the initial finite element model (FEM) is calibrated through model updating so that it captures the dynamic signature of the UCF Benchmark Structure in its healthy condition. Second, based upon collected data from the damaged condition, the updating process is repeated on the baseline (healthy) FEM. The difference between the updated parameters from subsequent stages revealed both location and extent of damage in a "blind" scenario, without any previous information about type and location of damage.

Fatigue experiments on steel cold-formed panels under a dynamic load protocol

Garcia-Palencia, Antonio J.,Godoy, Luis A. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.3

A dynamic load protocol has been used to experimentally simulate fatigue behavior in cold-formed metal panels with screwed connections under wind loading. The specific protocol adopted is an adaptation of SIDGERS, originally developed for non-metallic membranes, which is composed of levels each under increasing load values. A total of 19 tests were performed on 3.35 m long by 0.91 m wide panels, identified as Type B-wide rib and Type E, both with screw connections at the edge and at the center, thus conforming two-span specimens. In some configurations the panels were fixed at the valleys, whereas crest-fixed connections were also investigated. Reinforcing the connections by means of washers was also investigated to evaluate their efficiency in improving fatigue capacity. The experimental results show maximum load capacities in improved connections with washers of approximately twice of those with classical connections.

Fatigue experiments on steel cold-formed panels under a dynamic load protocol

Antonio J. García-Palencia,Luis A. Godoy 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.3

A dynamic load protocol has been used to experimentally simulate fatigue behavior in coldformed metal panels with screwed connections under wind loading. The specific protocol adopted is an adaptation of SIDGERS, originally developed for non-metallic membranes, which is composed of levels each under increasing load values. A total of 19 tests were performed on 3.35 m long by 0.91 m wide panels, identified as Type B-wide rib and Type E, both with screw connections at the edge and at the center, thus conforming two-span specimens. In some configurations the panels were fixed at the valleys, whereas crestfixed connections were also investigated. Reinforcing the connections by means of washers was also investigated to evaluate their efficiency in improving fatigue capacity. The experimental results show maximum load capacities in improved connections with washers of approximately twice of those with classical connections.

Burden of dengue among febrile patients at the time of chikungunya introduction in Piedecuesta, Colombia

Carabali, Mabel,Lim, Jacqueline K.,Palencia, Diana C.,Lozano‐,Parra, Anyela,Gelvez, Rosa Margarita,Lee, Kang Sung,Florez, Janeth P.,Herrera, Victor Mauricio,Kaufman, Jay S.,Rojas, Elsa M.,Villar John Wiley and Sons Inc. 2018 Tropical medicine & international health Vol.23 No.11

<P><B>Abstract</B></P><P><B>Objective</B></P><P>To estimate the age‐specific incidence of symptomatic dengue and chikungunya in Colombia.</P><P><B>Method</B></P><P>A passive facility‐based fever surveillance study was conducted among individuals with undifferentiated fever. Confirmatory diagnostics included serological and molecular tests in paired samples, and surveillance's underreporting was assessed using capture–recapture methods.</P><P><B>Results</B></P><P>Of 839 febrile participants 686 completed the study. There were 33.2% (295/839) dengue infections (51% primary infections), and 35.9% (191/532) of negative dengue cases there were chikungunya cases. On average, dengue cases were younger (median = 18 years) than chikungunya cases (median = 25 years). Thrombocytopaenia and abdominal pain were the main dengue predictors, while presence of rash was the main predictor for chikungunya diagnosis. Underreporting of dengue was 31%; the estimated expansion factors indicate an underreporting rate of dengue cases of threefold for all cases and of almost sixfold for inpatients.</P><P><B>Conclusions</B></P><P>These findings highlight the ongoing coexistence of both arboviruses, a distinct clinical profile of each condition in the study area that could be used by clinicians to generate a differential diagnosis, and the presence of underreporting, mostly among hospitalised cases.</P>

ETS transcription factor Etsrp / Etv2 is required for lymphangiogenesis and directly regulates <i>vegfr3 / flt4</i> expression

Davis, Jennifer A.,Koenig, Andrew L.,Lubert, Allison,Chestnut, Brendan,Liu, Fang,Palencia Desai, Sharina,Winkler, Tamara,Pociute, Karolina,Choi, Kyunghee,Sumanas, Saulius Elsevier 2018 Developmental Biology Vol.440 No.1

<P><B>Abstract</B></P> <P>The molecular mechanisms initiating the formation of the lymphatic system, lymphangiogenesis, are still poorly understood. Here we have identified a novel role in lymphangiogenesis for an ETS transcription factor, Etv2/Etsrp, a known regulator of embryonic vascular development. Through the use of fully validated photoactivatable morpholinos we show that inducible Etv2 inhibition in zebrafish embryos at 1 day post-fertilization (dpf) results in significant inhibition of lymphangiogenesis, while development of blood vessels is unaffected. In Etv2-inhibited embryos and larvae, the number of lymphatic progenitors is greatly reduced, the major lymphatic vessel, the thoracic duct, is absent or severely fragmented, and lymphangiogenesis-associated marker expression, including <I>lyve1b</I>, <I>prox1a</I>, and <I>vegfr3/flt4</I>, is strongly downregulated. We also demonstrate that lymphatic progenitors in Etv2 deficient embryos fail to respond to Vegfc signaling. Chromatin immunoprecipitation and sequencing (ChIP-Seq) studies using differentiated mouse embryonic stem (ES) cells as well as luciferase reporter studies in the ES cells and in zebrafish embryos argue that Etv2 directly binds the promoter/enhancer regions of Vegfc receptor <I>Vegfr3/Flt4</I> and lymphatic marker <I>Lyve1</I>, and promotes their expression. Together these data support a model where Etv2 initiates lymphangiogenesis by directly promoting the expression of <I>flt4</I> within the posterior cardinal vein.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Etv2 expression is enriched in the vein during zebrafish lymphangiogenesis. </LI> <LI> Inducible Etv2 knockdown inhibits lymphangiogenesis. </LI> <LI> Blood vessels are not affected by Etv2 knockdown at 24 hpf. </LI> <LI> Vegfc fails to induce lymphangiogenesis in Etv2 knockdown embryos. </LI> <LI> Etv2 directly binds to Flt4 promoter and promotes its expression. </LI> </UL> </P>

A multi-country study of the economic burden of dengue fever: Vietnam, Thailand, and Colombia

Lee, Jung-Seok,Mogasale, Vittal,Lim, Jacqueline K.,Carabali, Mabel,Lee, Kang-Sung,Sirivichayakul, Chukiat,Dang, Duc Anh,Palencia-Florez, Diana Cristina,Nguyen, Thi Hien Anh,Riewpaiboon, Arthorn,Chanth Public Library of Science 2017 PLoS neglected tropical diseases Vol.11 No.10

<▼1><P><B>Background</B></P><P>Dengue fever is a major public health concern in many parts of the tropics and subtropics. The first dengue vaccine has already been licensed in six countries. Given the growing interests in the effective use of the vaccine, it is critical to understand the economic burden of dengue fever to guide decision-makers in setting health policy priorities.</P><P><B>Methods/Principal findings</B></P><P>A standardized cost-of-illness study was conducted in three dengue endemic countries: Vietnam, Thailand, and Colombia. In order to capture all costs during the entire period of illness, patients were tested with rapid diagnostic tests on the first day of their clinical visits, and multiple interviews were scheduled until the patients recovered from the current illness. Various cost items were collected such as direct medical and non-medical costs, indirect costs, and non-out-of-pocket costs. In addition, socio-economic factors affecting disease severity were also identified by adopting a logit model. We found that total cost per episode ranges from $141 to $385 for inpatient and from $40 to $158 outpatient, with Colombia having the highest and Thailand having the lowest. The percentage of the private economic burden of dengue fever was highest in the low-income group and lowest in the high-income group. The logit analyses showed that early treatment, higher education, and better knowledge of dengue disease would reduce the probability of developing more severe illness.</P><P><B>Conclusions/Significance</B></P><P>The cost of dengue fever is substantial in the three dengue endemic countries. Our study findings can be used to consider accelerated introduction of vaccines into the public and private sector programs and prioritize alternative health interventions among competing health problems. In addition, a community would be better off by propagating the socio-economic factors identified in this study, which may prevent its members from developing severe illness in the long run.</P></▼1><▼2><P><B>Author summary</B></P><P>Dengue fever has been prevalent in South-East Asia and South America. Despite the increase of dengue fever cases, there continues to be a lack of economic assessment partly due to the absence of vaccines until recent times. Many of the previous economic burden studies for dengue fever were not standardized, making them difficult to compare. We implemented the standardized economic burden survey for dengue fever in a multi-country setting: Vietnam, Thailand, and Colombia. We found that the economic burden of dengue fever is substantial in all three dengue endemic countries. Our study also identified socio-economic factors which are related to the probability of experiencing severe illness. The first live attenuated, tetravalent dengue vaccine (CYD-TDV) has been already licensed in some dengue-endemic countries. As three countries will soon face decisions on whether and how to incorporate current and future vaccine candidates within their budget constraints, the updated economic burden estimates can be used to develop sustainable financing plans.</P></▼2>

Right-sided acute diverticulitis in the West: experience at a university hospital in Argentina

Huatuco René M. Palacios,Pachajoa Diana A. Pantoja,Liaño Julian E.,Molina Héctor A. Picón,Palencia Rafael,Doniquian Alejandro M.,Parodi Matías 대한대장항문학회 2023 Annals of Coloproctolgy Vol.39 No.2

Purpose: In the West, diverticular disease is located mainly in the left colon. However, it can also present in the right colon, with an incidence of 1%–2% in Caucasians. The purpose of this study was to describe our experience in right-sided acute diverticulitis (RD). Methods: In this retrospective study, 410 patients with acute diverticulitis treated from 2013 to 2020 were included in a university hospital in Córdoba, Argentina. Colonic diverticulitis was stratified into 2 groups; RD and left-sided acute diverticulitis. Demographic and clinical variables, laboratory and imaging findings, type of treatment, follow-up, and recurrence were analyzed. Results: Sixteen patients (3.9%) with RD were identified; 62.5% were male and the mean age was 40.7±11.7 years. A total of 81.3% were Caucasian and 18.7% Native American. Significant differences were found between both groups of diverticulitis; patients with RD were younger (P=0.001), with lower BMI (P=0.01), comorbidity rate (P=0.01), Charlson comorbidity index (P=0.02), hospital stay (P=0.01), severity according to the Hinchey classification (P=0.001) and had a lower recurrence rate (P=0.001). There were no significant differences in sex (P=0.95), duration of pain until admission (P=0.05), laboratory findings (P=0.23) and treatment (P=0.34). Conclusion: Conservative treatment predominated in RD, with a lower rate of complications and recurrences, providing data that support conservative therapy as initial treatment in RD in our environment.