Finite Element Analysis and Ambient Vibration Test of the Arch Type Steel Highway Bridges

In this paper, it is aimed to determine the dynamic characteristics of highway bridges using finite element analyses and ambient vibration tests. A modern steel highway bridge which has arch type structural system with 216 m total length and located in the Ayvacik county of Samsun, Turkey is selected as an application. Because of the fact that the bridge connects the villages which are separated with Suat Ugurlu Dam Lake, it has a major logistical importance for this region. The construction of the bridge is completed in 2009 and opened the traffic. An analytical modal analysis is performed on the developed 3D finite element model of the highway bridge to provide the analytical frequencies and mode shapes. The experimental measurements are carried out by ambient vibration tests under traffic loads. Vibration data are gathered from bridge deck. Measurement time, frequency span and effective mode number are determined by consider similar studies and literature. Enhanced Frequency Domain Decomposition method in the frequency domain and Stochastic Subspace Identification method in the time domain are used for the output only modal identification and dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined, experimentally. At the end of the study, analytically and experimentally identified dynamic characteristics are compared with each other. A good agreement is found between mode shapes, but some difference in natural frequencies

Early prenatal diagnosis of conjoined twins at 7 weeks and 6 days' gestation with two-dimensional Doppler ultrasound: a case report

This case report presents the prenatal diagnosis of conjoined twins at 7 weeks and 6 days’ gestation according to the last menstrual period and 6 weeks and 4 days’ gestation according to crown-rump length in a 32-year-old Turkish woman, using two-dimensional Doppler ultrasound. The twins were fused to each other at the thoracic region (thoracopagus). In the light of previous reports of conjoined twins this appears to be one of the earliest prenatally diagnosed cases in the medical literature

Sacralization may be associated with facet orientation and tropism but not degenerative changes of the lumbar vertebrae

Purpose: In this retrospective study, we aimed to investigate the possible effects of transitional vertebra anatomy on facet joint tropism and orientation by evaluating lumbar magnetic resonance imaging (MRI) studies performed at our institution. Material and methods: We included 84 patients with sacralization of the L5 vertebra and an equal number of patients with a radiology report within normal limits as the control group in our study. We compared facet tropism (FT) and orientation between both groups. Results: In both the sacralization group and the control group, the facet orientation angle showed a significant increasing trend from the L1-L2 level to the L5-S1 level (p < 0.001). The orientation angle of the L5-S1 level was higher in the sacralization group compared to the control group (p < 0.01). In the evaluation of FJ orientation between the sacralization and control groups, we found that coronal orientation was significantly more frequent at the L5-S1 level in the sacralization group. When the 2 groups were compared with regard to tropism at each spinal level, the sacralization group had a significantly higher FT frequency at the L5-S1 level (p < 0.001). Conclusions: To our knowledge, this is the first study to evaluate the relationship between sacralization and facet joint tropism. However, there were no relationships between facet degeneration, disc degeneration/herniation, and sacralization. Our results indicate that, although patients with sacralization and controls had similar characteristics in most assessments, they demonstrated significant differences at the L5-S1 level in terms of orientation and tropism

Prognostic Value of Lymph Node Ratio for Colorectal Cancer

Objective: This study was designed to assess the prognostic value of lymph node ratio (LNR) in patients with nonmetastatic colorectal cancer treated with radical resection

Pyrazinamide-Induced Anaphylaxis: Diagnosed by Skin Test and Successful Desensitization

Pyrazinamide (PZA), an antituberculosis drug, may cause hypersensitivity reactions. Here, we report a case of anaphylaxis secondary to a PZA administration for tuberculosis pleuritis. To the best of our knowledge, this is the first reported case of strongly possible IgE-mediated, PZA-induced anaphylaxis proved by skin prick test and oral provocation/desensitization. Copyright (C) 2011 S. Karger AG, Base

Effect of heavy metals in the meconium on preterm mortality: Preliminary study

Background There have been many studies that have investigated the risk factors of mortality in preterm infants, but none has shown an association between preterm mortality and exposure to heavy metals or trace elements. The aim of this study was therefore to measure the levels of toxic metals (lead, cadmium) and trace elements (zinc, iron, copper) in meconium samples and elucidate their association with preterm mortality. Methods Metals and trace elements were measured in the meconium of 304 preterm infants using a flame atomic absorption spectrophotometer. Results The level of heavy metals and trace elements in non-surviving infants was significantly higher than in surviving infants. Moreover, the level of heavy metals and trace elements in non-surviving infants whose gestational age was <30weeks (n=11) was significantly higher than in surviving infants (n=12). Receiver operating characteristic curve analysis showed that gestational age and meconium lead level predicted early mortality in premature newborns. Furthermore, this curve analysis showed that, when comparing meconium lead level and gestational age, meconium lead level had a similar effect on mortality as gestational age. Conclusion Meconium lead level and gestational age are associated with increased mortality risk in preterm neonates

The Effect of Heavy Metals and Trace Elements in the Meconium on Preterm Delivery of Unknown Etiology

Objective: Prematurity is an important etiologic factor for perinatal mortality and morbidity. In our country, preterm births and complications of prematurity account for 26% of perinatal mortality. There are many maternal, fetal or placental, genetic and environmental etiologic factors that cause prematurity. There have been no studies to show an association between preterm delivery of unknown etiology and exposure to heavy metals and trace elements at toxic levels in meconium. The purpose of this study is to measure the levels of heavy metals (lead, cadmium) and trace elements (zinc, iron, copper) in meconium samples and to understand their associations with preterm delivery of unknown etiology. Material and Methods: The levels of heavy metals and trace elements in the meconiums of 810 term or preterm infants with known and unknown etiology for being preterm were measured with a flame atomic absorption spectrophotometer. Results: Lead and cadmium were detected in all meconium samples. Heavy metal and trace element levels in meconium were significantly higher in preterms of unknown and known etiology for being preterm compared to term infants (for all p<0.0001). Lead levels in meconium were significantly higher in preterm of unknown etiology compared to preterm of known etiology in posthoc analysis with Bonferroni corrected Mann Whitney U test. Conclusion: These results may suggest that lead levels in meconium samples are higher in preterm newborns especially with unknown etiology compared to term newborns. Therefore, we suggest that preterm delivery of unknown etiology may be decreased by decreasing air pollution

Volumetric decrease of pancreas after abdominal irradiation, it is time to consider pancreas as an organ at risk for radiotherapy planning

Abstract Background Volumetric shrinkage of normal tissues such as salivary glands, kidneys, hippocampus are observed after radiotherapy. We aimed to assess the alterations in pancreatic volume of patients who received abdominal radiotherapy and define pancreas as an organ at risk for radiation treatment planning. Material-methods Forty-nine patients operated for gastric adenocarcinoma who received adjuvant abdominal radiotherapy were in the study group, 27 patients with early stage disease who did not need adjuvant treatment after surgery comprised the control group. An experienced radiologist contoured the pancreas of all the patients from computed tomographies imported to the planning system obtained either for radiation planning purpose or for follow-up after surgery. The same procedure was repeated one year later for both groups. Measured volume of the pancreas was expressed in cm3. Results Mean pancreatic volumes were similar in both groups at the onset of the study, 51,34 ± 20,33 cm3, and 50,12 ± 23,75 cm3 in the irradiated and the control groups respectively (p = 0,63). One year later, mean pancreatic volumes were significantly decreased in each group; 22,48 ± 10,53 cm3, 44,18 ± 23,08 cm3 respectively, p < 0,001. However, the decrease in pancreatic volume was significantly more pronounced in the irradiated group in comparison to the control group, p < 0,001. Conclusion Volumetric decrease in normal tissues after radiotherapy is responsible for loss of organ function and radiation related late side effects. Although pancreas is a radiation sensitive organ losing its volume and function after radiation exposure, it is not yet considered as an organ at risk for radiation treatment planning. Pancreas should be contoured as an organ at risk, dose-volume histogram for the organ should be created, and safe organ doses should be determined. This is the first study declaring pancreas as an organ at risk for radiation toxicity and the necessity of defining dose constraints for the organ