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This experimental work investigates the mechanical performance and ductility behavior of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) containing high volume of micro-glass fibers (MGF). The influence of various volume fractions of MGF and two water-to-binder ratios (w/b) are investigated. These w/b ratios are 0.12 and 0.14. Based on these ratios, two groups of UHPFRC mixes were prepared and each group include seven mixes made with 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3% MGF volume dosages. In total fourteen mixes were examined for the mechanical properties such as compressive strength, splitting tensile strength, modulus of elasticity, flexural strength; and the ductility behavior. It was concluded that lower w/b resulted in better mechanical performance. Also, the mixes containing 1.5% to 3% of MGF, resulted in the highest compressive strength reaching up to 160 MPa. Furthermore, the results indicated that no more strength enhancement can be achieved beyond 1.5% MGF.

The objective of this study is to utilize artificial cold bonded fly ash aggregate (AFA) in pervious concrete to produce a sustainable, and permeable concrete. The AFA were manufactured through cold bonding pelletization of fly ash (90 %) and Portland cement (10 %) in an inclined pan at ambient temperature. In this study, pervious concrete is manufactured by replacing the natural aggregates (NA) with AFA in five levels of replacements 0–100% with 25 % increments of the total aggregate’s volume. Two different concrete series were manufactured at 0.27 and 0.32 water-to-cement ratios (w/c). Totally, 10 pervious concretes were manufactured in this study. The utilized NA and AFA were uniformly graded and ranged 12.5 mm to 8 mm. In this study, the dry density and content of voids were determined. Furthermore, for the produced pervious concretes some tests were conducted such as compressive strength, splitting tensile, permeability and abrasion resistance. Besides, GLM-ANOVA as a statistical tool was employed to examine the effective parameter(s) on the properties of pervious concrete made using AFA. The results showed that with replacing the natural aggregate with 100 % AFA, the dry density of pervious concretes has decreased up to 22.4 % and the content of void and abrasion value has increased up to 20.8 %, and 153.8 %, respectively, for 0.27 w/c. In addition, the full replacement of NA with AFA resulted in a decrease of 51.5 % and 57.2 % in compressive strength and splitting tensile values made with w/c of 0.27. While, utilizing AFA significantly enhanced the permeability coefficient of the pervious concrete reaching maximum value of 10.27 mm/sec at w/c of 0.32.

Objective: The objective of this study was to investigate enamel remineralization using lyophilized extract from Moringa Oleifera Leaves (MOL). Materials and methods: A total of seventy-five teeth were selected and randomly divided into 5 equal groups (n = 15). All teeth were air dried for 30 s, two windows (right and left) were drawn on the labial surface of each tooth. The right window was set as the control and no etching or treatment was performed. The left window was etched for 30 s for all five groups. After etching, group I received no treatment, group II received plain varnish, group III received fluoride varnish, and finally groups IV and V received plain varnish loaded with 50 mg/ml and 200 mg/ml of lyophilized MOL extract respectively. All samples were then immersed in artificial saliva for 14 days. The specimens were examined under scanning electron microscope (SEM) and energy dispersive x-ray (EDX). Results: SEM micrographs revealed that MOL extract loaded-varnish groups IV & V showed the most re-establishment of normal enamel architecture. Elemental analysis of the treated surfaces of Groups IV and V showed the surfaces treated by MOL loaded-varnish groups had significantly higher Ca, P, and O deposition than the fluoride varnish group. Conclusion: MOL might be considered as a biomimetic material capable of guiding enamel tissue remineralization.

The mammalian target of rapamycin (mTOR) signaling network is frequently hyperactivated in patients with head and neck squamous cell carcinoma (HNSCC). Recent studies suggest that hypoxia, a common microenvironmental stress found in tumors, blocks this mitogenic pathway. Here, we demonstrate that in HNSCC cell lines, the expression of the phosphorylated forms of the mTOR downstream targets S6 kinase and S6 (pS6) decreased after hypoxia. These events were associated with a marked up-regulation of the regulated in development and DNA damage 1 (REDD1), a recently characterized hypoxia-induced protein that negatively controls mTOR activity. Conversely, pS6 levels were retained under hypoxia in REDD1 knock-down cells and in HNSCC cells lacking endogenous REDD1 expression. Furthermore, we observed that prolonged hypoxia induced an energy-depleting response as evidenced by decreased cellular ATP levels and AMP-activated protein kinase (AMPK) activation. Interestingly, AMPK inhibition before prolonged hypoxia prevented REDD1 expression, thereby sustaining mTOR activity. These results suggest a novel mechanism by which AMPK activation after hypoxia-induced energy stress may be crucial in regulating REDD1 expression to control the mTOR pathway in HNSCC. Furthermore, we found that, in some HNSCC cells, the reduced mTOR activity in response to hypoxia through AMPK/REDD1 was deregulated, which hence might contribute to the persistent activation of the mTOR pathway in this cancer type.

Microcrystalline cellulose (MCC) has been utilized as an adsorbent material for the removal of Pb(II) ions from aqueous solution after treatment with 1,2,3,4-butanetetracarboxylic acid (BTCA) at elevated temperature to obtain MMCC. The resulting adsorbent was characterized for point of zero point charge (pHZPC), estimation of carboxyl content, Fourier transform infrared spectroscopy (FT-IR), scan electron microscopy (SEM), and textural properties, including surface area, and subsequently utilized for the removal of Pb(II) ions from aqueous solution. The adsorption process was probed by investigating the effect of adsorbent dose, pH of solution, temperature, agitation time, and Pb(II) ion concentration. The results showed successful functionalization of MCC using BTCA, significantly improved the binding properties of the adsorbent towards Pb(II) ions. Isothermal adsorption data was analyzed using Langmuir, Freundlich and Temkin models, evaluated via nonlinear regression analysis. The maximum adsorption capacity was found to be 1155 mg/g (at pH 5 and 30 °C) from Langmuir theory, and appears independent of surface area. The Freundlich model was found to provide the best fit and the constant n was determined to be 2.69, indicating that adsorption of Pb(II) ions onto MMCC is favorable. Kinetic modelling showed good agreement for the pseudo-second order kinetic model, supporting the theory that chemisorption is involved in the adsorption process, which is promoted by a high density of active sites. Thermodynamic analysis showed that the adsorption of Pb(II) ions onto MMCC was endothermic and nonspontaneous; hence, MMCC offers an effective method of Pb(II) ion removal from aqueous solutions, with potential for water remediation processes., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Trovafloxacin (TVX) is a fluoroquinolone antibiotic whose therapeutic use was severely restricted due to an unacceptable risk of idiosyncratic liver injury. Oxidative stress and mitochondrial injury have been implicated in fluoroquinolone toxicity, but the mechanisms underlying liver injury are poorly understood. Because TVX-induced hepatotoxicity cannot be modeled in normal healthy rodents, we asked whether an underlying genetic defect (heterozygous deficiency in mitochondrial superoxide dismutase, Sod2) might aggravate TVX-induced mitochondrial adverse effects. Wild-type and Sod2(+/-) mice were treated with vehicle or alatrofloxacin (the prodrug of TVX, 33mg/kg/day, ip) for 28 days. We found that hepatic protein carbonyls were increased by 2.5-fold and hepatic mitochondrial aconitase activity was decreased by 20% in mutant, but not wild-type mice. Because aconitase is a major target of peroxynitrite, we determined the extent of nitrotyrosine residues in hepatic mitochondrial proteins. Trovafloxacin significantly increased nitrotyrosine in Sod2(+/-) mice only. Using the NO-selective probe DAF-2, we found that TVX increased the production of mitochondrial NO in immortalized human hepatocytes. Similarly, mitochondrial Ca(2+) was increased by TVX, suggesting Ca(2+)-dependent activation of mitochondrial NOS activity. Furthermore, the transcript levels of the mtDNA-encoded gene Cox2/mtCo2 were decreased in Sod2(+/-) mice only, while the expression of nDNA-encoded mitochondrial genes was not significantly altered in both genotypes, suggesting selective effects on mtDNA expression. The amount of mtDNA (copy number) was, however, unchanged. These data indicate that TVX enhances hepatic mitochondrial peroxynitrite stress in mice with underlying increased basal levels of superoxide, leading to the disruption of critical mitochondrial enzymes and gene regulation., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

The inhibition of 11betahydroxysteroid dehydrogenase 1 (11betaHSD1), an enzyme that catalyzes the conversion of inactive cortisone to active cortisol, is an attractive target to treat diabetes by suppressing hepatic gluconeogenesis. To test this hypothesis, we developed a novel glucocorticoid-induced diabetic KK mouse model and used 11betaHSD1 antisense oligonucleotide (ASO) as an inhibitory tool. KK mice were treated with 25 or 50mg/kg/day of 11betaHSD1 ASO for 28 days. On day 25, cortisone pellets were surgically implanted to induce diabetes. In the ASO-treated mice, plasma blood glucose levels were significantly reduced by up to 54%. In parallel, cortisol and other diabetes endpoints were also significantly reduced. Hepatic 11betaHSD1 mRNA was suppressed by up to 84% with a concomitant respective decrease of up to 49% in the expression of PEPCK. The results suggest that inhibition of 11betaHSD1 activity reduces the availability of cortisol to activate the glucocorticoid receptor, down regulates gluconeogenesis and thus reduces plasma glucose levels in cortisone-induced diabetic KK mice.

Objective: We tested the hypothesis that preterm delivery in women with twins or polyhydramnios is associated with enhanced expression and activity of cyclooxygenase type 2 in the amnion., Study Design: We obtained amniotic tissue samples from women undergoing preterm delivery complicated by either twins or polyhydramnios and also from women undergoing preterm cesarean delivery before or after labor. We measured amniotic prostaglandin E2 content and determined cyclooxygenase type 1 and type 2 expressions. We inhibited cyclooxygenase type 1 and type 2 activities with selective inhibitors., Results: Preterm delivery attributed to twins or polyhydramnios was associated with higher prostaglandin E2 production and enhanced amniotic expression of cyclooxygenase type 2. In contrast, cyclooxygenase type 1 expression was unchanged. Incubation of amniotic samples in vitro with either indomethacin or the selective cyclooxygenase type 2 inhibitor SC-236, but not with the cyclooxygenase type 1 inhibitor SC-560, effectively reduced prostaglandin E2 production., Conclusion: Preterm delivery related to multiple gestation or polyhydramnios was associated with enhanced amniotic expression and activity of cyclooxygenase type 2.