The use of wireless sensors in Structural Health Monitoring (SHM) has increased significantly in the last years. Piezoelectric-based lead zirconium titanate (PZT) sensors have been on the rise in SHM ...due to their superior sensing abilities. They are applicable in different technologies such as electromechanical impedance (EMI)-based SHM. This work develops a flexible wireless smart sensor (WSS) framework based on the EMI method using active sensors for full-scale and autonomous SHM. In contrast to passive sensors, the self-sensing properties of the PZTs allow interrogating with or exciting a structure when desired. The system integrates the necessary software and hardware within a service-oriented architecture approach able to provide in a modular way the services suitable to satisfy the key requirements of a WSS. The framework developed in this work has been validated on different experimental applications. Initially, the reliability of the EMI method when carried out with the proposed wireless sensor system is evaluated by comparison with the wireless counterpart. Afterwards, the performance of the system is evaluated in terms of software stability and reliability of functioning.
Summary
Objective
Recent studies report high rates of thyroid disorders in pregnant women. However, the need for universal thyroid screening remains controversial. Our aim was to estimate the ...prevalence of thyroid dysfunction (TD) during pregnancy and to analyse the association with maternal age.
Design and methods
We conducted a cross‐sectional study in a referral centre in collaboration with the primary care units from April 2010 to March 2011. The study included 2509 consecutive pregnant women resident in an iodine‐sufficient area, mean age 32 years (range 16–47) who were universally screened for TD in their first trimester (median gestation 8 weeks, range 4–13 weeks). Thyroid‐stimulating hormone (TSH) and free T4 (FT4) were analysed during the first antenatal visit. We applied first trimester‐specific population‐based TSH and FT4 reference ranges.
Results
We identified 416 women with positive TD screening 16·6%, 95% confidence interval (95% CI) 15·1–18·0. Of these, 47 had overt hypothyroidism (1·9%), 90 subclinical hypothyroidism (3·6%), 23 overt hyperthyroidism (0·9%), 20 subclinical hyperthyroidism (0·8%) and 236 had isolated hypothyroxinaemia (9·4%). Applying a logistic regression model, age ≥30 years was not associated with a higher risk of TD odds ratio (OR) 0·85, 95% CI 0·67–1·08 or hypothyroidism (OR 0·72, 95% CI 0·50–1·06).
Conclusions
TD affects one in six pregnant women in an iodine‐sufficient population. Maternal age ≥30 years do not increase the risk of TD.
Alkylphenolic compounds are chemicals with endocrine disrupting properties that have been widely used in industry with important changes in their usage over time. Few epidemiologic studies have ...evaluated the effect of alkylphenolic compounds on human health.
We investigated whether occupational exposure to alkylphenolic compounds is associated with breast and prostate cancer.
We carried out a population-based case–control study including 1513 incident cases of breast cancer, 1095 of prostate cancer, and 3055 controls, frequency matched by sex, age and region. Occupational exposure to alkylphenolic compounds was estimated using a recently developed job-exposure matrix, which considered different scenarios of exposure and different subtypes of alkylphenolic compounds.
History of occupational exposure to alkylphenolic compounds was modestly associated with breast cancer (OR = 1.23; 95% CI = 1.01–1.48). Within the different scenarios, the occupational use of domestic tensioactives was positively associated with breast cancer (OR = 1.28; 95% CI = 1.02–1.60), while occupational exposure in other scenarios showed mostly a suggestion of a similar positive associations. Exposure to nonylphenol ethoxylates was positively associated with breast cancer (OR = 1.21; 95% CI = 1.00–1.47), while exposure to other compounds was uncommon. In general, we did not observe associations between alkylphenolic compounds and prostate cancer, except for a positive association among men occupationally exposed to cosmetic, hair and personal hygiene products.
Our findings suggest a modest association between breast cancer risk and occupational exposure to alkylphenolic compounds, and no associations between these compounds and prostate cancer risk. These findings warrant further corroboration in other studies.
•This is the largest study examining occupational exposure to alkylphenolic compounds and breast and prostate cancer risk.•We observed a modest association between breast cancer risk and occupational exposure to alkylphenolic compounds.•Our findings suggest no significant associations for prostate cancer and these compounds.•Among women, nonylphenol ethoxylates were the most frequent compound, which was positively associated to breast cancer.•The elucidation of the role of these compounds should shed a light on the etiology of those diseases and help informing public health decisions.
AbstractHuman walking is a decisive excitation when checking vibration serviceability of several kinds of structures. Advanced models of walking load are needed to obtain realistic serviceability ...checks. This paper includes the study of the spatiotemporal parameters of human walking, which have a strong effect on the structural dynamic response. An advanced statistical model intended to simulate the temporal evolution of these parameters is sought. The modeling integrates previous related findings in biomechanics and results of a campaign of treadmill tests. An original model, in which the deviations of step interval are decomposed into a deterministic part due to asymmetry and a random part described by a second-order autoregressive process, is first established to model the intrasubject evolution of the step interval. The parameters of this model are formulated as a function of the walking speed, which constitutes a crucial innovation. The intersubject variability of the parameters of the previous model is then modeled statistically. The capability of the calibrated model to reproduce the experimental data is verified by comparing statistically the dynamic response of a virtual bridge in a variety of natural frequencies and walking speeds. The proposed model is more versatile than existing models because it is not restricted to a given distribution of walking speed, but it can be used in simulations with different distributions. Moreover, the application of the model can be extended to real-life walking, in which the average step speed is variable.
ObjectivesOur aim was to develop a job-exposure matrix (JEM) to assess occupational exposure to alkylphenolic compounds in epidemiological research, considering changes in their use over time, and ...including exposure probabilities in the assessments.MethodsWe consulted multiple sources of information, and performed interviews with 9 key people from industry and academia. 3 hygienists coded frequency (minority or majority of workers involved) and intensity of exposure (including dispersive processes, with shaking, or aerosol generation, or otherwise) to alkylphenolic compounds for all the 390 International Standard Classification of Occupations (ISCO)-88 job titles by period of time. Intensity and frequency of exposure were combined in a single score as follows: unlikely=0, occasionally+low intensity=1, occasionally+high intensity=2, frequent+low intensity=2, and frequent+high intensity=3.ResultsWe identified 54 (13.8%) of the 390 ISCO-88 job titles with potential exposure to alkylphenolic compounds. In 6 of jobs deemed as exposed, exposure depended on the economic sector of the occupation. Nonylphenol ethoxylates were the compounds most commonly involved (30 job titles, 55.6% of the exposed). Variations in alkylphenolic compounds use varied greatly over time; while they are still used in the plastic and rubber industry, in domestic cleaning agents their use began to decline before 1995.ConclusionsWe built a JEM to assess exposure to alkylphenolic compounds, taking into account changes in use over time, different types of alkylphenolic compounds and different scenarios of exposure, which can be a valuable tool for exposure assessment in epidemiological research on the health effects of these chemicals.
Abstract Background The effectiveness of a cannabis prevention program in high school students was assessed. Methods A quasi-experimental study was designed to evaluate the effectiveness of an ...intervention implemented in an intervention group (IG) with 39 schools compared with a control group (CG) of 47 schools not exposed to the intervention. Of 224 secondary schools in Barcelona, 86 were assessed in the 2005–2006 school year through a personal questionnaire administered at baseline and 15 months after the intervention. Participants consisted of 4848 ninth graders (14–15 year-olds), 2803 assigned to the IG and 2043 to the CG, according to the type and size of the school and the socioeconomic status of the school's neighborhood. The intervention consisted of a school-based cannabis prevention program (xkpts.com), with four sessions and 16 activities, implemented over 6–10 h, with materials for parents and web-based student involvement. Last-month cannabis use was assessed at baseline and at 15 months’ follow-up. Process evaluation indicators were assessed. Results At 15 months follow-up, 8.2% of boys and 8.3% of girls in the IG became last-month cannabis users versus 11.8% of boys and 11.6% of girls in the CG. These differences were statistically significant ( p = 0.003), representing a 29% reduction in last-month cannabis users in the IG compared with the CG. The incidence of last-month cannabis use was lowest in classrooms that adhered to the program protocol. Conclusions The xkpts.com program was effective in preventing progression to last-month cannabis use. Effectiveness was higher in classrooms that adhered closely to the protocol.
Abstract Malnutrition in hospitalized patients is associated with an increased risk of death and complications. The purpose of this study was to determine which nutrition-related risk index predicts ...mortality better in patients receiving total parenteral nutrition. This prospective, multicenter study involved noncritically ill patients who were prescribed total parenteral nutrition. Data were collected on Subjective Global Assessment (SGA), Nutritional Risk Index, Geriatric Nutritional Risk Index, body mass index, albumin and prealbumin, as well as in-hospital mortality, length of stay, and infectious complications. Of the 605 patients included in the study, 18.8% developed infectious complications and 9.6% died in the hospital. SGA, albumin, Nutritional Risk Index and Geriatric Nutritional Risk Index were associated with longer hospital stay. Prealbumin levels were associated with infectious complications. Multiple logistic regression analysis showed (after adjustment for age, sex, C-reactive protein levels, mean blood glucose levels, use of corticoids, prior comorbidity, carbohydrates infused, diagnosis, and infectious complications) that the SGA, Geriatric Nutritional Risk Index, body mass index, albumin, and prealbumin were associated with an increased risk for in-hospital mortality. SGA was the tool that best predicted mortality and adequately discriminated the values of the other nutrition-related risk indexes studied. The SGA is a clinically effective and simple tool for nutrition assessment in noncritically ill patients receiving total parenteral nutrition and detects the risk of inpatient mortality better than others.
Dynamic modeling and identification of the Uniovi structure Zapico-Valle, José Luis; García-Diéguez, Marta
International journal for simulation and multidisciplinary design optimization,
2014, 2014-00-00, 20140101, 2014-01-01, Letnik:
5
Journal Article
Recenzirano
Odprti dostop
The nonlinear modeling and identification of a four-storey steel frame is presented in this paper. The bending modes of the frame were experimentally isolated by a single-point mono-harmonic ...excitation and used for identification purposes. A novel expeditious procedure was developed to infer the kind of nonlinearities present in the structure. This turned out to be the most critical task in the modeling process. The proposed nonlinear model was calibrated in the time domain by fitting the model-predicted responses to the experiments. This was posed as the minimization of an error function by means of a new adaptive stochastic algorithm. Results were excellent. The calibrated nonlinear model yield fitting errors near three orders of magnitude lower than those of a pure linear model.
Contemporary design codes and guides for vibration serviceability assessment include some simplifications in load modelling. The same statistical distribution of the inter-pedestrian variability of ...the step interval (frequency) is proposed for all applications. Moreover, walking loads are considered to be periodic. The intra-pedestrian variability of the step interval is neglected. A more realistic load modelling trying to overcome the limitations of the codes is intended in this paper. Instead of a single mean value of the inter-pedestrian distribution of walking speed, a range of possible variation, which account for the real variations that occur in practice depending on the footbridge location and usage, is considered. An enhanced model is proposed in this paper to reproduce statistically both the intra- and inter-pedestrian variability of the step interval as a function of the walking speed distribution. This innovative model is then applied to study the sensitivity of the vertical response of footbridges to the variability of the step interval and to evaluate the influence of the aforementioned simplifications on the predicted characteristic responses. For this purpose, low-frequency footbridges excited by single-pedestrian crossings are chosen. The response is statistically characterized through Monte Carlo numerical simulations including 720 different configurations and 10,000 load cases in each configuration. Results of the study provide an overview of the influence of the footbridge and load parameters on the responses, which can be useful in practical applications where human–structure interactions are negligible. As for the simplifications of the codes, it is found that either using a single distribution to model the inter-pedestrian variability of the spatiotemporal parameters or neglecting the intra-pedestrian variability can lead to a significant underestimation of the characteristic response of footbridges.
IntroductionAlkylphenolic compounds are ubiquitous chemicals used as surfactants but having a wide range of other applications. Biologic matrices commonly used in epidemiologic studies, such as blood ...serum or plasma are not sensitive enough and too susceptible to contamination. Assessment of occupational exposure to alkylphenolic compounds may overcome these limitations. We developed a job-exposure matrix (JEM) to assess occupational exposure to alkylphenolic compounds in epidemiological research.MethodsWe consulted multiple sources of information, and performed interviews with nine key people from industry and academia. Three hygienists coded the frequency (minority or majority of workers involved) and intensity of exposure (including dispersive processes, with shaking, or aerosol generation, or otherwise) to alkylphenolic compounds for all the 390 ISCO-88 job titles by period of time.ResultsWe identified 57 (14.6%) out of 390 ISCO-88 job titles with potential exposure to alkylphenolic compounds. In 6 of jobs deemed as exposed, exposure depended on the economic sector of the occupation. Nonylphenol ethoxylates were the compounds most commonly involved (33 job titles, 57.9% of the exposed). Variations in alkylphenolic compounds use varied greatly over time; while they are still used in the plastic and rubber industry, in domestic cleaning agents their use began to decline before 1995.DiscussionWe built a JEM to assess exposure to alkylphenolic compounds, taking into account changes in use over time, different types of alkylphenolic compounds, and different scenarios of exposure, that can be a valuable tool for exposure assessment in epidemiologic research on the health effects of these chemicals.
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