23 research outputs found
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Fire resistance of axially restrained and partially unprotected Ultra Shallow Floor Beams (USFB®) and DELTABEAM® composite beams
Ultra-shallow floor types such as the USFB® and DELTABEAM® beam ‘plug’ composite flooring systems are recently developed and have seen many applications in contemporary construction. They involve partially encased steel beams in concrete, with the lower flange remaining exposed. Besides the satisfactory behavior of the system at ambient conditions, understanding their response to elevated temperatures is critical in evaluating their overall performance. Previous numerical studies of the authors have investigated their fire resistance when simply supported. The computational analyses demonstrated that such flooring systems are experiencing severe thermal gradients and bowing. When such beams are axially restrained, the compression due to the restraining may produce second order effects on the bowed beams. On the other hand, the effect of axial restraints is difficult to be estimated because of the temperature’s non-uniformity across the cross-sections. For this reason, comprehensive Finite Element Analyses (FEA) were implemented in this paper to simulate the response of such restrained beams subjected to fire. Material properties were modelled according to Eurocodes. The coupled thermal-structural parametric analyses involved different variations of the “shortest” cross-sections. From the FE analyses, useful conclusions are drawn
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Post-fire assessment and reinstatement of steel structures
Purpose
This paper aims to present technical aspects of the assessment method and evaluation of fire damaged steel structures. The current work focuses on the behavior of structural normal steel (hot-rolled and cold-formed) and high-strength bolts after exposure to elevated temperatures. Information on stainless steel, cast iron and wrought iron is also presented.
Design/methodology/approach
Because of the complexity of the issue, an elaborate presentation of the mechanical properties influencing factors is followed. Subsequently, a wide range of experimental studies is extensively reviewed in the literature while simplified equations for determining the post-fire mechanical properties are proposed, following appropriate categorization. Moreover, the reinstatement survey is also comprehensively described.
Findings
Useful conclusions are drawn for the safe reuse of the structural elements and connection components. According to the parametric investigation of the aforementioned data, it can be safely concluded that the most common scenario of buildings after fire events, i.e. apart from excessively distorted structures, implies considerable remaining capacity of the structure, highlighting that subsequent demolition should not be the case, especially regarding critical infrastructure and buildings.
Originality/value
The stability of the structure as a whole is addressed, with aim to establish specific guidelines and code provisions for the correct appraisal and rehabilitation of fire damaged structures
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Fire Resistance of Axially Restrained and Partially Unprotected Ultra Shallow Floor Beams (USFB) and DELTABEAM Composite Beams
peer reviewedUltra-shallow floor types such as the USFB® and DELTABEAM® beam ‘plug’ composite flooring systems are recently developed and have seen many applications in contemporary construction. They involve partially encased steel beams in concrete, with the lower flange remaining exposed. Besides the satisfactory behavior of the system at ambient conditions, understanding their response to elevated temperatures is critical in evaluating their overall performance. Previous numerical studies of the authors have investigated their fire resistance when simply supported. The computational analyses demonstrated that such flooring systems are experiencing severe thermal gradients and bowing. When such beams are axially restrained, the compression due to the restraining may produce second order effects on the bowed beams. On the other hand, the effect of axial restraints is difficult to be estimated because of the temperature’s non-uniformity across the cross-sections. For this reason, comprehensive finite element analyses (FEA) were implemented in this paper to simulate the response of such restrained beams subjected to fire. Material properties were modelled according to Eurocodes. The coupled thermal-structural parametric analyses involved different variations of the “shortest” cross-sections. From the FE analyses, useful conclusions are drawn
Common Adverse Effects of Anti-TNF Agents on Gestation
Autoimmune disease has affected up to 50 million Americans, according to the American Autoimmune Related Diseases Association (AARDA) and 75 percent of those affected are women. These inflammatory diseases have variable activity and a lot of women will have to undergo major therapies during and after pregnancy. Many of the women suffering from these disease will improve during gestation. However a lot of women will require continuation of disease-modifying therapies (i.e., biological therapies) throughout pregnancy and post-partum involving many risks. In the past decade all gaze turned to biological therapies, as an attempt, to obtain even more effective medications in order to suppress the exacerbation of autoimmune disease, even at the most unfit circumstances such as pregnancy. The results are both satisfying and promising since increasingly proven thoughts prevail on making anti-TNF agents first-line medications, clearing up the limited knowledge over human influence. The purpose of this review is to summarize the results of the reports with the highest and representative range of patients of the last decade involving the use of anti-TNF agents during pregnancy. Copyright © 2016 Zacharias Fasoulakis et al
The social stigma of HIV–AIDS: society's role
Emmanuel N Kontomanolis, Spyridon Michalopoulos, Grigorios Gkasdaris, Zacharias Fasoulakis Department of Obstetrics and Gynecology, Democritus University of Thrace, Alexandroupolis, Greece Abstract: AIDS is a devastating and deadly disease that affects people worldwide and, like all infections, it comes without warning. Specifically, childbearing women with AIDS face constant psychological difficulties during their gestation period, even though the pregnancy itself may be normal and healthy. These women have to deal with the uncertainties and the stress that usually accompany a pregnancy, and they have to live with the reality of having a life-threatening disease; in addition to that, they also have to deal with discriminating and stigmatizing behaviors from their environment. It is well known that a balanced mental state is a major determining factor to having a normal pregnancy and constitutes the starting point for having a good quality of life. Even though the progress in both technology and medicine is rapid, infected pregnant women seem to be missing this basic requirement. Communities seem unprepared and uneducated to smoothly integrate these people in their societies, letting the ignorance marginalize and isolate these patients. For all the aforementioned reasons, it is imperative that society and medical professionals respond and provide all the necessary support and advice to HIV-positive child bearers, in an attempt to allay their fears and relieve their distress. The purpose of this paper is to summarize the difficulties patients with HIV infection have to deal with, in order to survive and merge into society, identify the main reasons for the low public awareness, discuss the current situation, and provide potential solutions to reducing the stigma among HIV patients. Keywords: AIDS, stigma, pregnancy, HIV, infection, society, social discriminatio
Rare distant metastatic disease of ovarian and peritoneal carcinomatosis: A review of the literature
Background: Although metastases of ovarian and peritoneal carcinomatosis are most commonly found within the peritoneal cavity, there is a number of other rare distant sites that have been reported. Our goal is to provide an evidence-based summary of the available literature considering the rare distant metastatic sites of ovarian and peritoneal carcinomatosis. Methods: A comprehensive search of the literature was conducted, with Medline/PubMed being searched for cases of rare metastatic disease originated from primary ovarian and peritoneal cancer with related articles up to 2019 including terms such as “ovarian cancer”, “metastases”, “peritoneal” and others. Results: The most common mechanism of ovarian cancer metastases consists of primarily dissemination within the peritoneal cavity, while, rare and distant sites can either occur at the beginning or during the course of the disease and they are usually associated with hematogenous route and lymphatic invasion, having poor prognosis, with the least common sites being skin, bone, CNS, eye, placenta, central airways, rare lymph nodes, intra-abdominal organs, heart and breast. Conclusions: The occurrence of metastatic sites described in this review represents the most common rare distant metastatic sites, and even though their patterns of metastases are still not fully clarified due to the rarity of the reports, they offer valuable information considering the pathophysiology of the disease. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Preoperative Bowel Preparation in Minimally Invasive and Vaginal Gynecologic Surgery
Bowel preparation traditionally refers to the removal of bowel contents via mechanical cleansing measures. Although it has been a common practice for more than 70 years, its use is based mostly on expert opinion rather than solid evidence. Mechanical bowel preparation in minimally invasive and vaginal gynecologic surgery is strongly debated, since many studies have not confirmed its effectiveness, neither in reducing postoperative infectious morbidity nor in improving surgeons' performance. A comprehensive search of Medline/PubMed and the Cochrane Library Database was conducted, for related articles up to June 2019, including terms such as "mechanical bowel preparation," "vaginal surgery," "minimally invasive," and "gynecology." We aimed to determine the best practice regarding bowel preparation before these surgical approaches. In previous studies, bowel preparation was evaluated only via mechanical measures. The identified randomized trials in laparoscopic approach and in vaginal surgery were 8 and 4, respectively. Most of them compare different types of preparation, with patients being separated into groups of oral laxatives, rectal measures (enema), low residue diet, and fasting. The outcomes of interest are the quality of the surgical field, postoperative infectious complications, length of hospital stay, and patients' comfort during the whole procedure. The results are almost identical regardless of the procedure's type. Routine administration of bowel preparation seems to offer no advantage to any of the objectives mentioned above. Taking into consideration the fact that in most gynecologic cases there is minimal probability of bowel intraluminal entry and, thus, low surgical site infection rates, most scientific societies have issued guidelines against the use of any bowel preparation regimen before laparoscopic or vaginal surgery. Nonetheless, surgeons still do not use a specific pattern and continue ordering them. However, according to recent evidence, preoperative bowel preparation of any type should be omitted prior to minimally invasive and vaginal gynecologic surgeries. © 2020 Michail Diakosavvas et al
Heterotopic tubal pregnancy with a naturally conceived live twin intrauterine pregnancy in a patient with systemic lupus erythematosus: A case report
Heterotopic pregnancy (HP) is defined as the simultaneous occurrence of an intrauterine and extrauterine gestation. Risk factors contributing to this condition are similar to those which contribute to ectopic pregnancy. While a triple heterotopic gestation through natural conception is uncommon, here we present the case of a patient with spontaneous intrauterine twins and a concurrent tubal extrauterine gestation, where the patient also had systemic lupus erythematosus. During the seventh week of gestation, the patient presented with acute abdomen signs and hemodynamic instability; a decision was taken to perform an emergency laparotomy. Haemoperitoneum, a total torsion of the right ovary with salpinx, a ruptured tubal pregnancy and subsequent necrosis were found intraoperatively. The patient was discharged on the sixth postoperative day and monitored throughout her whole pregnancy, with the intrauterine pregnancy progressing uneventfully. Two healthy neonates were delivered by cesarean section at 36 weeks of gestation. In conclusion, physicians treating women of reproductive age should be aware of possible HP, even in the absence of risk factors. © 202
Heterotopic tubal pregnancy with a naturally conceived live twin intrauterine pregnancy in a patient with systemic lupus erythematosus: A case report
Heterotopic pregnancy (HP) is defined as the simultaneous occurrence of an intrauterine and extrauterine gestation. Risk factors contributing to this condition are similar to those which contribute to ectopic pregnancy. While a triple heterotopic gestation through natural conception is uncommon, here we present the case of a patient with spontaneous intrauterine twins and a concurrent tubal extrauterine gestation, where the patient also had systemic lupus erythematosus. During the seventh week of gestation, the patient presented with acute abdomen signs and hemodynamic instability; a decision was taken to perform an emergency laparotomy. Haemoperitoneum, a total torsion of the right ovary with salpinx, a ruptured tubal pregnancy and subsequent necrosis were found intraoperatively. The patient was discharged on the sixth postoperative day and monitored throughout her whole pregnancy, with the intrauterine pregnancy progressing uneventfully. Two healthy neonates were delivered by cesarean section at 36 weeks of gestation. In conclusion, physicians treating women of reproductive age should be aware of possible HP, even in the absence of risk factors. © 202