The probabilistic-based assessment of Moment Resisting Frame structure (MRFs) is significantly vital due to the high volatility of blast wave propagation parameters, material strength, and strain ...rate effect. In this study, the reliability and sensitivity of steel MRFs equipped with Nickel Titanium Shape Memory Alloy (NiTi SMA), and smart MRFs, subjected to Vehicle Borne Improvised Explosive Device (VBIED) are assessed. Since Eurocode does not address the design of a smart structure subjected to blast loading, the smart MRFs are designed based on the Eurocode-complying key design procedures proposed by the author’s previous works. It is always a question if the structure designed based on the proposed Eurocode-complying design methodology satisfies the safety level criteria. The newly developed reliability framework approach by the authors is employed to assess the safety level of the smart MRFs based on the criteria given in the international probabilistic design provisions. Performance functions are parameterized based on three failure modes: axial force and bending moments (global buckling) in the columns, maximum rotation demand at the connections, and system-level structural integrity through Inter-Story Drift Ratio (ISDR). The uncertainties of the charge weight, material strength, gravity loads, model uncertainties, connection behavior parameters, strain rate effects, and column cross-sectional dimensions are considered. The proposed reliability framework is applied to the 4-story, 7-story, 10-story, and 15-story smart MRFs. The results show that the developed smart MRFs satisfy the safety level criteria recommended in the international provisions’ probabilistic design requirement. Furthermore, the reliability-based outcome confirms the efficiency and applicability of the proposed Eurocode complying key design procedures and verifies the deterministic results of the smart MRFs. Finally, the sensitivity of the smart structures to various uncertain parameters is investigated. Among all the parameters, it is found that the Reliability Index (β) of the smart MRFs is more sensitive to the uncertainties of charge weight, column web length(s), connection behavior parameters, and material strength. The sensitivity analysis shows that the smart MRFs are safe under unknown extreme conditions, a very high Coefficient of Variation (COV).
•Steel MRFs equipped with Nickle Titanium Shape Memory Alloy (NiTi SMA) are investigated probabilistically.•The reliability of smart MRFs and its application are examined as blast protective structure.•A developed reliability assessment framework is comprehensively used to assess the safety level of smart steel MRFs.•The efficiency of the proposed Eurocode-complying key design rules is evaluated.•To determine the most sensitive parameters, a detailed sensitivity analysis is conducted.
Organisms have evolved to survive rigorous environments and are not prepared to thrive in a world of caloric excess and sedentary behavior. A realization that physical exercise (or lack of it) plays ...a pivotal role in both the pathogenesis and therapy of type 2 diabetes mellitus (t2DM) has led to the provocative concept of therapeutic exercise mimetics. A decade ago, we attempted to simulate the beneficial effects of exercise by treating t2DM patients with 3 weeks of daily hyperthermia, induced by hot tub immersion. The short-term intervention had remarkable success, with a 1 % drop in HbAl, a trend toward weight loss, and improvement in diabetic neuropathic symptoms. An explanation for the beneficial effects of exercise and hyperthermia centers upon their ability to induce the cellular stress response (the heat shock response) and restore cellular homeostasis. Impaired stress response precedes major metabolic defects associated with t2DM and may be a near seminal event in the pathogenesis of the disease, tipping the balance from health into disease. Heat shock protein inducers share metabolic pathways associated with exercise with activation of AMPK, PGC1-a, and sirtuins. Diabetic therapies that induce the stress response, whether via heat, bioactive compounds, or genetic manipulation, improve or prevent all of the morbidities and comorbidities associated with the disease. The agents reduce insulin resistance, inflammatory cytokines, visceral adiposity, and body weight while increasing mitochondrial activity, normalizing membrane structure and lipid composition, and preserving organ function. Therapies restoring the stress response can re-tip the balance from disease into health and address the multifaceted defects associated with the disease.
Buckling Restrained Braces (BRB) are innovative displacement dependent devices having balanced hysteretic behavior. Frames equipped with such devices are known as Buckling Restrained Braced Frames ...(BRBF). Application of BRB elements in Europe is seriously limited by the lack of a standardized European design procedure for BRBF.
In the first part of this paper the authors propose a Eurocode conforming design procedure for BRBF and provide the seismic design parameters and capacity design rules by enhancing Eurocode 8 specifications on steel Concentrically Braced Frames. This second part introduces 24 BRBF archetypes designed with the proposed procedure. Their performance under seismic excitation is investigated by nonlinear dynamic analysis in an environment developed by the authors through improvement of the methodology in FEMA P-695. Feasibility of the proposed design procedure is evaluated as a function of conditional failure probability of the archetype buildings.
The presented assessment required detailed experimental studies on BRB behavior and development of a novel material model that can simulate complex nonlinear hardening under irregular cyclic loading. The material model is implemented in the OpenSees finite element code. A software environment was developed for automatic evaluation of braced frames using OpenSees.
The sufficiently low collapse probability of BRBF archetypes confirms the applicability of the proposed design procedure in Europe.
•Eurocodes do not regulate the design of Buckling Restrained Braced Frames.•The first part of this paper introduces the proposed modifications to Eurocode 8.•Performance of BRBF designed with the proposed procedure is investigated.•A sample performance evaluation illustrates the assessment methodology.•Low collapse probability of BRBF confirms design procedure applicability.
Prior to modern seismic codes, several road bridges were not designed for earthquakes in many moderate seismic regions. The seismic performance of these bridges is questionable. A portfolio of 30 ...non-seismically designed bridges is compiled for seismic reliability assessment. Fragility analysis is conducted, and the reliability of each structure is determined considering typical moderate seismic areas. The study shows that slab and multi-girder bridges with elastomeric bearings perform worse, whereas girder bridges with conventional bearings and multi-girder bridges with monolithic joints have better behavior. It is also shown that seismic design per Eurocode 8 leads to a reliability index of ~2.
Numerous recent studies have pointed out that in case of extreme effects (such as fire or seismic effects) the reliability level of structures is lower than in case of conventional effects. Proper ...estimation of reliability in fire design situation is complicated since there is no comprehensive methodology defined for it; and the commonly used methods apply great simplifications. In former studies the reliability calculations are carried out mainly for simple, separated elements, while simple structural behaviour is assumed. Further research work is needed to refine rules and define targeted safety levels required by fire codes. The current study presents methodology for calculating the reliability of structures subjected to fire; its main novelties are as follows: a) the reliability calculation is not limited to a single, isolated element but the whole structure as a complex system is considered; b) the methodology is capable of taking any type of fire curve into account; c) in the reliability analysis nonlinear global analysis of the whole structure is involved; d) the structural reliability is assessed on time basis. To justify the applicability of the proposed methodology, reliability analysis for a tapered steel frame protected by intumescent coating is presented as an illustrative numerical example. Probability of its failure is calculated by using First Order Reliability Method; the computed failure probabilities are verified by using Monte Carlo Simulation. FORM approximation underestimates the failure probability, the observed error is within −1% to −34%. Based on the results, it has been found that for low and moderate consequence classes the calculated reliability indices are in better agreement with the recommendations of ISO 2394 standard and Joint Committee on Structural Safety than with the values recommended in EN 1990:2002 standard.
•In this paper a complex and comprehensive framework is presented for reliability analysis of structures exposed to fire.•The reliability is assessed on time basis which provides a practical and informative basis for the designer.•The reliability calculation focuses on the whole structure, thus the reliability is calculated for the structural system.•The structural reliability depends on the function of the investigated facility and on the quantity of combustible materials.•The proposed framework is efficient and reasonable accurate compared with the results of Monte Carlo Simulation.
Abstract Background Obesity is a growing problem worldwide and a major risk factor for many chronic diseases. The accumulation of adipose tissue leads to the release of significant amounts of ...pro-inflammatory cytokines and adipokines, resulting in a low-grade systemic inflammation. However, the mechanisms behind the development of obesity-related diseases are not fully understood. Therefore, our study aimed to investigate the pathological changes and inflammatory processes at systemic level and in individual organs in two different diet-induced mouse obesity models. Methods Male C57BL6/J mice were fed by high-fat diet (HFD), high-fat/high-fructose diet (HFD + FR) or normal chow for 21 weeks starting at 3 months of age ( n = 15 animals/group). Insulin resistance was tested by oral glucose tolerance test. Pathological changes were investigated on hematoxylin – eosin-stained liver and brown adipose tissue sections. The gene expression levels of adipokines and cytokines were analyzed by qPCR in adipose tissues, whereas serum protein concentrations were determined by multiplex immunoassays. Immunophenotyping of isolated blood, bone marrow and spleen cells was performed by single-cell mass cytometry. Results Weight gain, glucose intolerance and hepatic steatosis were more severe in the HFD + FR group than in the control and HFD groups. This was accompanied by a higher level of systemic inflammation, as indicated by increased expression of pro-inflammatory genes in visceral white adipose tissue and by a higher serum TNFα level. In addition, immunophenotyping revealed the increase of the surface expressions of CD44 and CD69 on various cell types, such as CD8+ and CD4 + T-cells, B-cells and macrophages, in animals with obesity. Conclusions The combination of HFD with fructose supplementation promotes more properly the symptoms of metabolic syndrome. Therefore, the combined high-fat/high-fructose nutrition can be a more suitable model of the Western diet. However, despite these differences, both models showed immunophenotypic changes that may be associated with increased risk of obesity-related cancer.
Immunization of mice with a 14-mer peptide TKDNNLLGRFELSG, termed "TKD," comprising amino acids 450–461 (aa 450–461 ) in the C terminus of inducible Hsp70, resulted in the generation of an IgG1 mouse ...mAb cmHsp70.1. The epitope recognized by cmHsp70.1 mAb, which has been confirmed to be located in the TKD sequence by SPOT analysis, is frequently detectable on the cell surface of human and mouse tumors, but not on isogenic cells and normal tissues, and membrane Hsp70 might thus serve as a tumor-specific target structure. As shown for human tumors, Hsp70 is associated with cholesterol-rich microdomains in the plasma membrane of mouse tumors. Herein, we show that the cmHsp70.1 mAb can selectively induce antibody-dependent cellular cytotoxicity (ADCC) of membrane Hsp70⁺ mouse tumor cells by unstimulated mouse spleen cells. Tumor killing could be further enhanced by activating the effector cells with TKD and IL-2. Three consecutive injections of the cmHsp70.1 mAb into mice bearing CT26 tumors significantly inhibited tumor growth and enhanced the overall survival. These effects were associated with infiltrations of NK cells, macrophages, and granulocytes. The Hsp70 specificity of the ADCC response was confirmed by preventing the antitumor response in tumor-bearing mice by coinjecting the cognate TKD peptide with the cmHsp70.1 mAb, and by blocking the binding of cmHsp70.1 mAb to CT26 tumor cells using either TKD peptide or the C-terminal substrate-binding domain of Hsp70.
Buckling Restrained Braces (BRB) are innovative displacement dependent devices having balanced hysteretic behavior. Frames equipped with such devices are known as Buckling Restrained Braced Frames ...(BRBF). Application of BRB elements in Europe is seriously limited by the lack of a standardized European design procedure for BRBF.
In the first part of this paper the authors propose a Eurocode conforming design procedure for BRBF and provide the seismic design parameters and capacity design rules by enhancing Eurocode 8 specifications on steel Concentrically Braced Frames. Major extensions concern rules for static and dynamic analyses, calculation of material and structural overstrength, unbalanced loads, braced frame column sections and a BRBF-specific behavior factor. Brief examples explain the motivation for each modification and justify the proposed regulations. The complete design procedure is illustrated through the design of a sample six-story BRBF.
The authors developed a probabilistic seismic performance evaluation environment on the basis of the methodology in FEMA P-695. The second part of this paper shows how the performance of the proposed design procedure was evaluated with that environment. Results confirmed the applicability of the proposed design procedure in Europe.
•Eurocodes do not regulate the design of Buckling Restrained Braced Frames.•The authors propose a Eurocode conforming BRBF design procedure.•The rules of Eurocode 8 on steel Concentrically Braced Frames are extended.•A sample design illustrates the proposed design procedure.•The second part of this paper shows verification of design procedure performance.
The ability of photosynthetic organisms to adapt to increases in environmental temperatures is becoming more important with climate change. Heat stress is known to induce heat-shock proteins (HSPs) ...many of which act as chaperones. Traditionally, it has been thought that protein denaturation acts as a trigger for HSP induction. However, increasing evidence has shown that many stress events cause HSP induction without commensurate protein denaturation. This has led to the membrane sensor hypothesis where the membrane’s physical and structural properties play an initiating role in the heat shock response.
In this review, we discuss heat-induced modulation of the membrane’s physical state and changes to these properties which can be brought about by interaction with HSPs. Heat stress also leads to changes in lipid-based signaling cascades and alterations in calcium transport and availability. Such observations emphasize the importance of membranes and their lipids in the heat shock response and provide a new perspective for guiding further studies into the mechanisms that mediate cellular and organismal responses to heat stress.
In lack of seismic provisions in the pre-Eurocode ages, most of the existing Hungarian bridges were not designed for seismic actions, therefore their seismic performance is questionable. The most ...commonly used structural type in highway construction is the integral precast multi-girder bridge. These bridges are typically constructed as continuous multi-support systems with monolithic joints at each support, thus their behavior may be significantly different from those applying simply supported beams and conventional bearings. A parametric fragility analysis of a wide range of different layouts is carried out using detailed and advanced non-linear numerical models. The results indicate that the abutment joints are highly vulnerable and piers are also critical for longer bridges. The study implies that without seismic design, integral precast multi-girder bridges are highly susceptible to pier shear failure, the probability of collapse is relatively high. The results also provide a solid basis for retrofit planning as well as for development of design concepts of newly built structures in moderate seismic zones.
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