scholarly journals Nonlinear Simulation and Vulnerability Analysis of Masonry Structures Impacted by Flash Floods

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Qi Fang ◽  
Shuguang Liu ◽  
Guihui Zhong ◽  
Hong Zhang ◽  
Jiyu Liang ◽  
...  
Keyword(s):  
Critical Role ◽  
Damage Index ◽  
Flash Floods ◽  
Masonry Structures ◽  
Physical Vulnerability ◽  
Nonlinear Simulation ◽  
Explicit Finite Element ◽  
Structural Resistance ◽  
Structural Measure ◽  
The Impact

The vulnerability of buildings impacted by flash floods is often assessed by empirical approaches. However, the damage-developing mechanisms of buildings remain unclear. This study presented a nonlinear numerical analysis for the interaction between flash floods and masonry structures. A new Structured ALE (S-ALE) solver in an explicit finite element platform LS-DYNA was applied. Thirty different scenarios, including two different FE models, three different water depths, and five different flow velocities, were studied. Nonlinear structural responses and failure mechanisms of masonry structures were analyzed and compared. Results showed that due to the consideration of wall damage, the time evolution of the impact force on the entire building was distributed in a multipeak pattern. Under the impact of flash floods, the building was in a complex bending-shear state, and the overturning moment was the principal reason for the building damage. The critical role played by the structural measure was reaffirmed. Moreover, the physical vulnerability was quantified through a macroscopic damage index, the lateral drift ratio of the ground floor. It can be concluded that the physical vulnerability depends on both the local structural strength (local view) and the structural resistance hierarchies (global view).

scholarly journals An analysis of physical vulnerability to flash floods in the small mountainous watershed of Aceh Besar Regency, Aceh province, Indonesia

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
A. Azmeri ◽  
Amir H. Isa
Keyword(s):  
At Risk ◽  
Loss Rate ◽  
Flash Floods ◽  
Mitigation Strategies ◽  
Physical Vulnerability ◽  
Aceh Province ◽  
The Impact ◽  
The Relationship ◽  
Elements At Risk ◽  
Polynomial Distribution

Vulnerability is a loss rate perceived from elements at risk owing to the impact of hazards on determined magnitude and frequency. Vulnerability assessment of elements at risk is a critical component in the risk assessment framework. Considerable studies regarding flash floods have been conducted, but the depth of information on vulnerability is still limited. This study presents a model of the physical vulnerability of buildings caused by the incidence of flash floods, which is strengthened through intensity of the impact process and loss. This model used a non-linear regression approach using behavioural data in the form of the propagation height of the flood. The order-2 polynomial distribution can represent the relationship between the magnitudes of the best process and loss rate. The results are the risk assessments of an exposed area in mitigation strategies.

scholarly journals Physical vulnerability of reinforced concrete buildings impacted by snow avalanches

2010 ◽  
Vol 10 (7) ◽  
pp. 1531-1545 ◽  
Author(s):  
D. Bertrand ◽  
M. Naaim ◽  
M. Brun
Keyword(s):  
Reinforced Concrete ◽  
Numerical Simulations ◽  
Damage Index ◽  
Impact Pressure ◽  
Snow Avalanche ◽  
Reference Structure ◽  
Snow Avalanches ◽  
Physical Vulnerability ◽  
Engineering Structures ◽  
The Impact

Abstract. This paper deals with the assessment of physical vulnerability of civil engineering structures to snow avalanche loadings. In this case, the vulnerability of the element at risk is defined by its damage level expressed on a scale from 0 (no damage) to 1 (total destruction). The vulnerability of a building depends on its structure and flow features (geometry, mechanical properties, type of avalanche, topography, etc.). This makes it difficult to obtain vulnerability relations. Most existing vulnerability relations have been built from field observations. This approach suffers from the scarcity of well documented events. Moreover, the back analysis is based on both rough descriptions of the avalanche and the structure. To overcome this problem, numerical simulations of reinforced concrete structures loaded by snow avalanches are carried out. Numerical simulations allow to study, in controlled conditions, the structure behavior under snow avalanche loading. The structure is modeled in 3-D by the finite element method (FEM). The elasto-plasticity framework is used to represent the mechanical behavior of both materials (concrete and steel bars) and the transient feature of the avalanche loading is taken into account in the simulation. Considering a reference structure, several simulation campaigns are conducted in order to assess its snow avalanches vulnerability. Thus, a damage index is defined and is based on global and local parameters of the structure. The influence of the geometrical features of the structure, the compressive strength of the concrete, the density of steel inside the composite material and the maximum impact pressure on the damage index are studied and analyzed. These simulations allow establishing the vulnerability as a function of the impact pressure and the structure features. The derived vulnerability functions could be used for risk analysis in a snow avalanche context.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

scholarly journals The lung–gut axis during viral respiratory infections: the impact of gut dysbiosis on secondary disease outcomes

2021 ◽  
Author(s):  
Valentin Sencio ◽  
Marina Gomes Machado ◽  
François Trottein
Keyword(s):  
Gut Microbiota ◽  
Bacterial Infections ◽  
Respiratory Infections ◽  
Critical Role ◽  
Good Health ◽  
Disease Outcomes ◽  
And Function ◽  
Viral Respiratory Infections ◽  
The Impact ◽  
Viral Respiratory

AbstractBacteria that colonize the human gastrointestinal tract are essential for good health. The gut microbiota has a critical role in pulmonary immunity and host’s defense against viral respiratory infections. The gut microbiota’s composition and function can be profoundly affected in many disease settings, including acute infections, and these changes can aggravate the severity of the disease. Here, we discuss mechanisms by which the gut microbiota arms the lung to control viral respiratory infections. We summarize the impact of viral respiratory infections on the gut microbiota and discuss the potential mechanisms leading to alterations of gut microbiota’s composition and functions. We also discuss the effects of gut microbial imbalance on disease outcomes, including gastrointestinal disorders and secondary bacterial infections. Lastly, we discuss the potential role of the lung–gut axis in coronavirus disease 2019.

scholarly journals Methionine Diet Evoked Hyperhomocysteinemia Causes Hippocampal Alterations, Metabolomics Plasma Changes and Behavioral Pattern in Wild Type Rats

2021 ◽  
Vol 22 (9) ◽  
pp. 4961
Author(s):  
Maria Kovalska ◽  
Eva Baranovicova ◽  
Dagmar Kalenska ◽  
Anna Tomascova ◽  
Marian Adamkov ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Brain Area ◽  
Critical Role ◽  
Cerebrovascular Diseases ◽  
Behavioral Pattern ◽  
Cell Physiology ◽  
Male Wistar Rats ◽  
High Level ◽  
Hippocampal Alterations ◽  
The Impact

L-methionine, an essential amino acid, plays a critical role in cell physiology. High intake and/or dysregulation in methionine (Met) metabolism results in accumulation of its intermediate(s) or breakdown products in plasma, including homocysteine (Hcy). High level of Hcy in plasma, hyperhomocysteinemia (hHcy), is considered to be an independent risk factor for cerebrovascular diseases, stroke and dementias. To evoke a mild hHcy in adult male Wistar rats we used an enriched Met diet at a dose of 2 g/kg of animal weight/day in duration of 4 weeks. The study contributes to the exploration of the impact of Met enriched diet inducing mild hHcy on nervous tissue by detecting the histo-morphological, metabolomic and behavioural alterations. We found an altered plasma metabolomic profile, modified spatial and learning memory acquisition as well as remarkable histo-morphological changes such as a decrease in neurons’ vitality, alterations in the morphology of neurons in the selective vulnerable hippocampal CA 1 area of animals treated with Met enriched diet. Results of these approaches suggest that the mild hHcy alters plasma metabolome and behavioural and histo-morphological patterns in rats, likely due to the potential Met induced changes in “methylation index” of hippocampal brain area, which eventually aggravates the noxious effect of high methionine intake.

scholarly journals NLRP7 Promotes Choriocarcinoma Growth and Progression through the Establishment of an Immunosuppressive Microenvironment

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2999
Author(s):  
Deborah Reynaud ◽  
Roland Abi Nahed ◽  
Nicolas Lemaitre ◽  
Pierre-Adrien Bolze ◽  
Wael Traboulsi ◽  
...  
Keyword(s):  
Immune Response ◽  
Tumor Cells ◽  
Major Gene ◽  
Critical Role ◽  
Orthotopic Model ◽  
Independent Manner ◽  
Maternal Immune Response ◽  
The Impact

The inflammatory gene NLRP7 is the major gene responsible for recurrent complete hydatidiform moles (CHM), an abnormal pregnancy that can develop into gestational choriocarcinoma (CC). However, the role of NLRP7 in the development and immune tolerance of CC has not been investigated. Three approaches were employed to define the role of NLRP7 in CC development: (i) a clinical study that analyzed human placenta and sera collected from women with normal pregnancies, CHM or CC; (ii) an in vitro study that investigated the impact of NLRP7 knockdown on tumor growth and organization; and (iii) an in vivo study that used two CC mouse models, including an orthotopic model. NLRP7 and circulating inflammatory cytokines were upregulated in tumor cells and in CHM and CC. In tumor cells, NLRP7 functions in an inflammasome-independent manner and promoted their proliferation and 3D organization. Gravid mice placentas injected with CC cells invalidated for NLRP7, exhibited higher maternal immune response, developed smaller tumors, and displayed less metastases. Our data characterized the critical role of NLRP7 in CC and provided evidence of its contribution to the development of an immunosuppressive maternal microenvironment that not only downregulates the maternal immune response but also fosters the growth and progression of CC.

scholarly journals Training may enhance early childhood educators’ self-efficacy to lead physical activity in childcare

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Brianne A. Bruijns ◽  
Andrew M. Johnson ◽  
Jennifer D. Irwin ◽  
Shauna M. Burke ◽  
Molly Driediger ◽  
...  
Keyword(s):  
Physical Activity ◽  
Early Childhood ◽  
Self Efficacy ◽  
Critical Role ◽  
Early Childhood Educators ◽  
Outdoor Play ◽  
Future Research ◽  
Intervention Component ◽  
Space Extension ◽  
The Impact

Abstract Background Early childhood educators (ECEs) play a critical role in promoting physical activity (PA) among preschoolers in childcare; thus, PA-related training for ECEs is essential. The Supporting PA in the Childcare Environment (SPACE) intervention incorporated: 1. shorter, more frequent outdoor play sessions; 2. provision of portable play equipment; and, PA training for ECEs. An extension of the SPACE intervention (the SPACE-Extension) incorporated only the shorter, more frequent outdoor play periods component of the original SPACE intervention. The purpose of this study was to explore the individual impact of these interventions on ECEs’ PA-related self-efficacy and knowledge. Methods ECEs from the SPACE (n = 83) and SPACE-Extension (n = 31) were administered surveys at all intervention time-points to assess: self-efficacy to engage preschoolers in PA (n = 6 items; scale 0 to 100); self-efficacy to implement the intervention (n = 6 items); and, knowledge of preschooler-specific PA and screen-viewing guidelines (n = 2 items). A linear mixed effects model was used to analyze the impact of each intervention on ECEs’ self-efficacy and knowledge and controlled for multiple comparison bias. Results The SPACE intervention significantly impacted ECEs’ self-efficacy to engage preschoolers in PA for 180 min/day (main effect), and when outdoor playtime was not an option (interaction effect). Further, the interaction model for ECEs’ knowledge of the total PA guideline for preschoolers approached significance when compared to the main effects model. Participants within the SPACE-Extension did not demonstrate any significant changes in self-efficacy or knowledge variables. Conclusions Findings from this study highlight the benefit of ECE training in PA with regard to fostering their PA-related self-efficacy and knowledge. Future research should explore the impact of PA training for ECEs uniquely in order to determine if this intervention component, alone, can produce meaningful changes in children’s PA behaviours at childcare.

scholarly journals Arginine Decarboxylase Is Essential for Pneumococcal Stress Responses

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 286
Author(s):  
Mary Frances Nakamya ◽  
Moses B. Ayoola ◽  
Leslie A. Shack ◽  
Mirghani Mohamed ◽  
Edwin Swiatlo ◽  
...  
Keyword(s):  
Stress Responses ◽  
Critical Role ◽  
Acid Stress ◽  
Arginine Decarboxylase ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Cellular Processes ◽  
Opportunistic Human Pathogen ◽  
Thiol Peroxidase ◽  
The Impact

Polyamines such as putrescine, cadaverine, and spermidine are small cationic molecules that play significant roles in cellular processes, including bacterial stress responses and host–pathogen interactions. Streptococcus pneumoniae is an opportunistic human pathogen, which causes several diseases that account for significant morbidity and mortality worldwide. As it transits through different host niches, S. pneumoniae is exposed to and must adapt to different types of stress in the host microenvironment. We earlier reported that S. pneumoniae TIGR4, which harbors an isogenic deletion of an arginine decarboxylase (ΔspeA), an enzyme that catalyzes the synthesis of agmatine in the polyamine synthesis pathway, has a reduced capsule. Here, we report the impact of arginine decarboxylase deletion on pneumococcal stress responses. Our results show that ΔspeA is more susceptible to oxidative, nitrosative, and acid stress compared to the wild-type strain. Gene expression analysis by qRT-PCR indicates that thiol peroxidase, a scavenger of reactive oxygen species and aguA from the arginine deiminase system, could be important for peroxide stress responses in a polyamine-dependent manner. Our results also show that speA is essential for endogenous hydrogen peroxide and glutathione production in S. pneumoniae. Taken together, our findings demonstrate the critical role of arginine decarboxylase in pneumococcal stress responses that could impact adaptation and survival in the host.

scholarly journals Mechanosensation and Mechanotransduction by Lymphatic Endothelial Cells Act as Important Regulators of Lymphatic Development and Function

2021 ◽  
Vol 22 (8) ◽  
pp. 3955
Author(s):  
László Bálint ◽  
Zoltán Jakus
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Mechanical Forces ◽  
Lymphatic Endothelial Cells ◽  
Lymphatic Development ◽  
And Function ◽  
The Impact

Our understanding of the function and development of the lymphatic system is expanding rapidly due to the identification of specific molecular markers and the availability of novel genetic approaches. In connection, it has been demonstrated that mechanical forces contribute to the endothelial cell fate commitment and play a critical role in influencing lymphatic endothelial cell shape and alignment by promoting sprouting, development, maturation of the lymphatic network, and coordinating lymphatic valve morphogenesis and the stabilization of lymphatic valves. However, the mechanosignaling and mechanotransduction pathways involved in these processes are poorly understood. Here, we provide an overview of the impact of mechanical forces on lymphatics and summarize the current understanding of the molecular mechanisms involved in the mechanosensation and mechanotransduction by lymphatic endothelial cells. We also discuss how these mechanosensitive pathways affect endothelial cell fate and regulate lymphatic development and function. A better understanding of these mechanisms may provide a deeper insight into the pathophysiology of various diseases associated with impaired lymphatic function, such as lymphedema and may eventually lead to the discovery of novel therapeutic targets for these conditions.

scholarly journals A non-toxic, reversibly released imaging probe for oral cancer that is derived from natural compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Magda Ghanim ◽  
Nicola Relitti ◽  
Gavin McManus ◽  
Stefania Butini ◽  
Andrea Cappelli ◽  
...  
Keyword(s):  
Oral Cancer ◽  
Cancer Progression ◽  
Intraoperative Imaging ◽  
Critical Role ◽  
Water Soluble ◽  
Stem Cell Marker ◽  
Squamous Cells ◽  
Tissue Identification ◽  
Tumorigenic Potential ◽  
The Impact

AbstractCD44 is emerging as an important receptor biomarker for various cancers. Amongst these is oral cancer, where surgical resection remains an essential mode of treatment. Unfortunately, surgery is frequently associated with permanent disfigurement, malnutrition, and functional comorbidities due to the difficultly of tumour removal. Optical imaging agents that can guide tumour tissue identification represent an attractive approach to minimising the impact of surgery. Here, we report the synthesis of a water-soluble fluorescent probe, namely HA-FA-HEG-OE (compound 1), that comprises components originating from natural sources: oleic acid, ferulic acid and hyaluronic acid. Compound 1 was found to be non-toxic, displayed aggregation induced emission and accumulated intracellularly in vesicles in SCC-9 oral squamous cells. The uptake of 1 was fully reversible over time. Internalization of compound 1 occurs through receptor mediated endocytosis; uniquely mediated through the CD44 receptor. Uptake is related to tumorigenic potential, with non-tumorigenic, dysplastic DOK cells and poorly tumorigenic MCF-7 cells showing only low intracellular levels and highlighting the critical role of endocytosis in cancer progression and metastasis. Together, the recognised importance of CD44 as a cancer stem cell marker in oral cancer, and the reversible, non-toxic nature of 1, makes it a promising agent for real time intraoperative imaging.

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