Nonlinear Model for Reinforced Concrete under Cyclic Loading

Most of the available shear models for reinforced concrete rely on empirical formulations. In this study, a rational shear stress function is used to define the shear stress–strain envelope for reinforced concrete. Cyclic rules are proposed to define the loading, unloading and reloading relationships for reinforced concrete under shear stress reversals. A normal stress function describing the cyclic relationship of concrete under axial stress is also introduced. The proposed functions are verified using experimental data of reinforced concrete panels tested under monotonic and cyclic loading. Subsequently, the normal and shear stress functions along with their cyclic rules are integrated in a non-linear finite element analysis code. The resulting model accounts for tension stiffening, crack opening and closing, compression hardening and softening, degradation of concrete strength and stiffness in the direction parallel to the crack, compression unloading and reloading, as well as non-linear steel behaviour (strain hardening and Bauschinger effect). The finite element model is then used to analyse two Portland Cement Association shear walls with different geometries tested under cyclic loading. The results show a good agreement between analytical and experimental data. The model showed an excellent capacity of predicting shear deformations of reinforced concrete elements under cyclic loading with minimal computational efforts

Inhibition effect of famotidine towards the corrosion of C-steel in sulphuric acid Solution

The inhibition effect of  famotidine drug  towards  the corrosion of C-steel in 0.5M H2SO4 was studied using weight loss, gasometry, potentiodynamic polarization and electrochemical frequency modulation (EFM) techniques, as well as, surface examination by SEM. The inhibition mechanism of FA is based on the adsorption process forming a film barrier layer protect the steel from acid attack. The adsorption is found to obey Frundlich model. The inhibition efficiency increased by increasing inhibitor concentration and decreased with temperature. Some thermodynamic parameters for adsorption process are deduced and discussed. Keywords: C-steel, famotidine, Adsorption, Corrosion

Using age, arterial lactate level and sequential organ failure assessment score in risk stratification of sepsis syndromes

Introduction: In low income countries, ICU places are limited and not all sepsis patients will benefit from ICU admission. Stratification is an important step to identify patients who require ICU treatment from patients who can be treated on general ward setting. Improper stratification results in increased length of stay, costs, morbidity and mortality. Objective: The aim of this study was to stratify the risk of mortality in patients with sepsis syndrome using age, arterial lactate level and SOFA score. Methods: In this prospective observational study, 250 patients with sepsis were enrolled and followed up until discharge. They were categorized into 2 groups according to 7-days mortality. Results: SOFA score (≥5) was the only good tool (AUC=0.722) while age (≥65 years) (AUC=0.650) and arterial lactate (≥3.25 mmol/L) (0.690) were fair tools to predict 7-days mortality. A new score “ALSOFA score” (≥10) was an excellent tool for prediction (AUC =0.912, 95%CI: 0.851 to 0.940, p<0.0001). It showed an excellent sensitivity (90.9%) and specificity (85.1%). Conclusion: In critically ill patients with sepsis syndromes, age, arterial lactate and SOFA score are fair tools of stratification. No single marker/score can be used alone to stratify such patients

Identification of genes differentially expressed in onion infected with Iris yellow spot virus

Iris yellow spot virus (IYSV) causes severe damage and economic losses in onion production. Differential display-PCR was used to study changes in the gene expression of IYSV-infected onion plants. Representative up-regulated and down-regulated genes were selected for further study. Based on sequence analysis, the up-regulated genes were identified as retrotransposon protein, disease resistance-like proteins, chitinase, pathogenesis-related protein, cytochrome oxidase, cytochrome c, pentatricopeptide repeat-containing protein and pectin methylesterase. A DNA-binding transcriptional repressor protein gene was greatly down-regulated. . Most of the identified genes are known to play essential roles in plant defence systems, and are newly identified in onion sequences

Toward systems-informed models for biologics disposition: covariates of the abundance of the neonatal Fc Receptor (FcRn) in human tissues and implications for pharmacokinetic modelling

Biologics are a fast-growing therapeutic class, with intertwined pharmacokinetics and pharmacodynamics, affected by the abundance and function of the FcRn receptor. While many investigators assume adequacy of classical models, such as allometry, for pharmacokinetic characterization of biologics, advocates of physiologically-based pharmacokinetics (PBPK) propose consideration of known systems parameters that affect the fate of biologics to enable a priori predictions, which go beyond allometry. The aim of this study was to deploy a systems-informed modelling approach to predict the disposition of Fc-containing biologics. We used global proteomics to quantify the FcRn receptor [p51 and β2-microglobulin (B2M) subunits] in 167 samples of human tissue (liver, intestine, kidney and skin) and assessed covariates of its expression. FcRn p51 subunit was highest in liver relative to other tissues, and B2M was 1–2 orders of magnitude more abundant than FcRn p51 across all sets. There were no sex-related differences, while higher expression was confirmed in neonate liver compared with adult liver. Trends of expression in liver and kidney indicated a moderate effect of body mass index, which should be confirmed in a larger sample size. Expression of FcRn p51 subunit was approximately 2-fold lower in histologically normal liver tissue adjacent to cancer compared with healthy liver. FcRn mRNA in plasma-derived exosomes correlated moderately with protein abundance in matching liver tissue, opening the possibility of use as a potential clinical tool. Predicted effects of trends in FcRn abundance in healthy and disease (cancer and psoriasis) populations using trastuzumab and efalizumab PBPK models were in line with clinical observations, and global sensitivity analysis revealed endogenous IgG plasma concentration and tissue FcRn abundance as key systems parameters influencing exposure to Fc-conjugated biologics

Special Section on Pediatric Drug Disposition and Pharmacokinetics-Minireview Ontogeny of Hepatic Drug Transporters and Relevance to Drugs Used in Pediatrics

ABSTRACT Most of the pharmacokinetic studies conducted to calculate pediatric drug doses are based on scaling from adult data using various allometric parameters related to body size. However, these uniform scaling methods cannot account for all physiologic changes occurring during maturation, which influence various drugs in different ways. The ontogeny of physiologic and biologic functions accompanying the progression from infancy to childhood to adulthood does not proceed in a simple monotonic rate with body size for various elimination pathways. The transporters and their interplay with enzymes have a substantial role in drug metabolism and disposition. Although much is known about enzymes and their ontogeny, there is a scarcity of information on the ontogenic profile of drug transporters, particularly during the early years of human life. These ontogeny data are required for the enhancement of physiologically based pharmacokinetic models, and consequently for the prediction of pharmacokinetic profiles of new therapeutic compounds in pediatric populations. This review points to the relative ontogeny rate for enzymes and transporters and how these may confound our understanding of the role that transporters may or may not play in childhood compared with adulthood

Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery

Peer reviewe