STRUCTURAL INVESTIGATION OF HEIGHT - IRREGULAR- STEEL BRACED STRUCTURES AGAINST PROGRESSIVE COLLAPSE

Considering failure scenarios caused by a progressive collapse of structural systems subjected to special loadings such as explosion, impact, fire, design error and excessive unexpected loads is one of the main challenges that nowadays structural engineers encounter. Progressive collapse is defined as propagation of local failure of a structural member to other members that ultimately leads to failure of the whole structure or a portion of it. The effect of irregularities and the use of viscous damper in structural behavior of steel braced buildings against progressive collapse is the spotlight of this study. Three different steel buildings (5, 9 and 13 stories) with vertical irregularities are considered and analyzed with PERFORM 3D software. In the first part of this study, different scenarios for a sudden elimination of columns are modeled and the effect of irregularities on the pattern of collapse is studied. Then viscous dampers are used in the model to study whether they are able to prevent or mitigate the dynamic effects caused by the progressive collapse. The results show that the corner columns of the buildings are more sensitive than side columns. In addition, installing viscous dampers in the structure can improve its dynamic behavior to some extent

Intensive care unit, cardiac care unit, and emergency department nurses' perceptions of medical device-related pressure injuries: a cross-sectional study

Background Nurses' perception of medical device-related pressure injuries (MDRPIs) may affect their performance, but there is a lack of studies in this area. Purpose The current study aimed to examine intensive care unit (ICU), cardiac care unit (CCU) and emergency department nurses' perception of proper prevention of MDRPIs and care for individuals with such injuries. Methods This descriptive study was conducted in 4 general hospitals in Iran in 2021. All nurses (N = 310) working in ICUs, CCUs and emergency departments of these facilities were invited to complete a researcher-made demographic checklist and an 11-item questionnaire to assess attitudes toward MDRPIs. The questionnaire item responses were scored from 1 (strongly agree) to 5 (strongly disagree) with the total score for the 11 items ranging from 11 to 55. A score of 11 to 25 was categorized as indicating a negative attitude toward proper prevention of MDRPIs and care for such patients; a score of 26 to 40 indicated a neutral attitude, and a score >40 indicated a positive attitude. Results A total of 260 nurses fulfilled the data collection tool. The response rate was 83.8%. The mean total score of attitude toward MDRPIs was 41.7. No significant relationship was observed between the total score of nurses' attitudes and their demographic variables. Of the 260 participants, 159 stated they had not received any trainings on MDRPIs at nursing schools during their education, 212 stated they had not participated in any scientific workshops on MDRPIs, and 167 described their knowledge about the prevention and care of MDRPIs as insufficient. Conclusion Among ICU, CCU, and emergency nurses in Iran, most had a positive attitude toward the prevention and care of MDRPIs, but steps should be taken to offer more opportunities for nurses to increase their knowledge in this area

Additively manufactured multi-morphology bone-like porous scaffolds: experiments and micro-computed tomography-based finite element modeling approaches

Tissue engineering, whose aim is to repair or replace damaged tissues by combining the principle of biomaterials and cell transplantation, is one of the most important and interdisciplinary fields of regenerative medicine. Despite remarkable progress, there are still some limitations in the tissue engineering field, among which designing and manufacturing suitable scaffolds. With the advent of additive manufacturing (AM), a breakthrough happened in the production of complex geometries. In this vein, AM has enhanced the field of bioprinting in generating biomimicking organs or artificial tissues possessing the required porous graded structure. In this study, triply periodic minimal surface structures, suitable to manufacture scaffolds mimicking bone's heterogeneous nature, have been studied experimentally and numerically; the influence of the printing direction and printing material has been investigated. Various multi-morphology scaffolds, including gyroid, diamond, and I-graph and wrapped package graph (I-WP), with different transitional zone, have been three-dimensional (3D) printed and tested under compression. Further, a micro-computed tomography (µCT) analysis has been employed to obtain the real geometry of printed scaffolds. Finite element analyses have been also performed and compared with experimental results. Finally, the scaffolds' behavior under complex loading has been investigated based on the combination of µCT and finite element modeling

Body composition and basal metabolic rate in systemic lupus erythematosus patients

Aim of the work: Descriptions of the body composition parameters and metabolism in systemic lupus erythematosus (SLE) patients are limited. The aim of the present work was to assess the body composition factors and basal metabolic rate (BMR) in Iranian SLE patients and to study its relation to disease activity. Patients and methods: Seventy-four female SLE patients and 76 matched controls were included in the present study. The body mass index (BMI), body fat (BF), visceral fat (VF), body muscle (BM) and basal metabolic rate (BMR) were measured using BIA (bioelectrical impedance analysis). The international physical activity questionnaire (IPAQ) was used to assess physical activity. SLE disease activity index (SLEDAI) was assessed for all the patients. Results: The mean age of the patients was 38.5 ± 10.1 years with a median disease duration of 7.5 years. The median SLEDAI was 4. Body composition factors (BMI, BF, VF, and BM) were not significantly different between the patients and their controls. The BMR in SLE patients was significantly lower (1328.4 ± 154.6 kcal/day) than the controls (1400.4 ± 200.4 kcal/day) (p = 0.01). No differences have been found in body composition parameters and BMR between the SLE patients with high and low SLEDAI or daily corticosteroid dose. There was no significant correlation between the SLEDAI and any of the studied parameters except for a negative association with age (r = −0.3, p = 0.03). Conclusion: SLE women have a significantly lower BMR compared to their controls. No significant differences have been observed regarding BMI, BF, BM and VF between the groups

In vitro static and dynamic cell culture study of novel bone scaffolds based on 3D-printed PLA and cell-laden alginate hydrogel

The aim of this paper was to design and fabricate a novel composite scaffold based on the combination of 3D-printed PLA-based triply minimal surface structures (TPMS) and cell-laden alginate hydrogel. This novel scaffold improves the low mechanical properties of alginate hydrogel and can also provide a scaffold with a suitable pore size, which can be used in bone regeneration applications. In this regard, an implicit function was used to generate some Gyroid TPMS scaffolds. Then the fused deposition modeling (FDM) process was employed to print the scaffolds. Moreover, the micro-CT technique was employed to assess the microstructure of 3D-printed TPMS scaffolds and obtain the real geometries of printed scaffolds. The mechanical properties of composite scaffolds were investigated under compression tests experimentally. It was shown that different mechanical behaviors could be obtained for different implicit function parameters. In this research, to assess the mechanical behavior of printed scaffolds in terms of the strain-stress curves on, two approaches were presented: equivalent volume and finite element-based volume. Results of strain-stress curves showed that the finite-element based approach predicts a higher level of stress. Moreover, the biological response of composite scaffolds in terms of cell viability, cell proliferation, and cell attachment was investigated. In this vein, a dynamic cell culture system was designed and fabricated, which improves mass transport through the composite scaffolds and applies mechanical loading to the cells, which helps cell proliferation. Moreover, the results of the novel composite scaffolds were compared to those without Alginate, and it was shown that the composite scaffold could create more viability and cell proliferation in both dynamic and static cultures. Also, it was shown that scaffolds in dynamic cell culture have a better biological response than in static culture. In addition, Scanning electron microscopy was employed to study the cell adhesion on the composite scaffolds, which showed excellent attachment between the scaffolds and cells

In vitrostatic and dynamic cell culture study of novel bone scaffolds based on 3D-printed PLA and cell-laden alginate hydrogel

The aim of this paper was to design and fabricate a novel composite scaffold based on the combination of 3D-printed polylactic acid-based triply periodic minimal surfaces (TPMSs) and cell-laden alginate hydrogel. This novel scaffold improves the low mechanical properties of alginate hydrogel and can also provide a scaffold with a suitable pore size, which can be used in bone regeneration applications. In this regard, an implicit function was used to generate some gyroid TPMS scaffolds. Then the fused deposition modeling process was employed to print the scaffolds. Moreover, the micro computed tomography technique was employed to assess the microstructure of 3D-printed TPMS scaffolds and obtain the real geometries of printed scaffolds. The mechanical properties of composite scaffolds were investigated under compression tests experimentally. It was shown that different mechanical behaviors could be obtained for different implicit function parameters. In this research, to assess the mechanical behavior of printed scaffolds in terms of the strain-stress curves on, two approaches were presented: equivalent volume and finite element-based volume. Results of strain-stress curves showed that the finite-element based approach predicts a higher level of stress. Moreover, the biological response of composite scaffolds in terms of cell viability, cell proliferation, and cell attachment was investigated. In this vein, a dynamic cell culture system was designed and fabricated, which improves mass transport through the composite scaffolds and applies mechanical loading to the cells, which helps cell proliferation. Moreover, the results of the novel composite scaffolds were compared to those without alginate, and it was shown that the composite scaffold could create more viability and cell proliferation in both dynamic and static cultures. Also, it was shown that scaffolds in dynamic cell culture have a better biological response than in static culture. In addition, scanning electron microscopy was employed to study the cell adhesion on the composite scaffolds, which showed excellent attachment between the scaffolds and cells

Thinking about persuasive technology from the strategic business perspective:a call for research on cost-based competitive advantage

Abstract Persuasive system features have been extensively examined, and many of them have been shown to be effective in supporting individuals’ achieving their behavioral goals and enhancing system use. Also, companies and organizations have utilized persuasive features in their implementations successfully. However, in order to obtain competitive advantage, organizations need to not only take using persuasive features as differentiation strategy, but also to think about cost of developing persuasive systems. While the research on evaluating persuasive features is important, we argue that previous research has ignored the cost of building persuasive features. As a first step in remedying this gap in research, we present and discuss four research directions for studying cost of developing persuasive systems. This study contributes to persuasive technology field by paving the way for a new research area with highly practical implications