Ductile corrosion-free self-centering concrete elements

Corrosion is a major factor in the deterioration of reinforced concrete (RC) structures. To mitigate this problem, steel bars can be replaced with glass-fiber-reinforced-polymer (GFRP) bars. However, the lack of ductility of GFRP-RC elements has prevented their use in many structural applications, especially in seismic areas. Superelastic shape memory alloy (SMA) bars have been proposed to be used in seismic areas because of their self-centering characteristics. Also, they have the added advantage of being corrosion resistant. This paper examines the combined use of SMA and GFRP bars to achieve ductile self-centering and corrosion-free elements. The first challenge for such a proposal relates to designing concrete frames, reinforced with SMA and GFRP bars, that have adequate lateral performance in terms of initial stiffness, ductility, and strength. A comprehensive parametric study is conducted to better understand the structural behavior of concrete elements reinforced with SMA and/or GFRP bars. Results from the study are utilized to develop design equations that allow designing an SMA/GFRP RC section to replace a steel RC section, while maintaining lateral strength, stiffness, and ductility. To examine the adequacy of the developed equations, a six-storey concrete frame is designed, and its lateral performance is examined using pushover analysis

Ductile Corrosion-Free GFRP-Stainless Steel Reinforced Concrete Elements

Corrosion of steel rebars is known to cause deterioration of concrete structures that can lead to catastrophic failures. To mitigate this problem, steel rebars can be replaced with Glass Fiber-Reinforced Polymer (GFRP) rebars. However, the lack of ductility of GFRP-reinforced elements has prevented their use in many structural applications, especially in seismic areas. Stainless Steel (SS) rebars are corrosion resistant and have adequate energy absorption and ductility. However, they are much more expensive than steel rebars. This paper proposes the combined use of SS and GFRP rebars to achieve ductile and corrosion-free elements. The first challenge for such a proposal relates to designing SS-GFRP reinforced concrete frame with adequate lateral performance in terms of initial stiffness, ductility, and strength. Design equations, which are based on a comprehensive parametric study, are developed to allow designing such a frame. A six-storey concrete frame is then designed using the proposed equations and its lateral performance is examined using pushover analysis

Seaweed Extracts Enhance Salam Turfgrass Performance during Prolonged Irrigation Intervals and Saline Shock

The negative effects of the ongoing climate change include unusual prolonged droughts and increased salinity pressures on the agricultural lands. Consequently, crops are facing unprecedented environmental pressure, and this calls for more research toward controlling such major stresses. The current study investigates the effects of seaweed extract sprays of Ascophyllum nodosum (5 and 7 mL·L−1; 6 day intervals) on Paspalum vaginatum Salam' during prolonged irrigation intervals (2 and 6 day) and saline growing conditions (1 and 49.7 dS·m−1) for 6 weeks in containers under greenhouse conditions. Control plants showed reduced turf quality, photochemical efficiency, root length and dry weight, total non-structural carbohydrates, and K and Ca compositions. Seaweed extracts increased turf quality, leaf photochemical efficiency, root length and dry weight, total non-structural carbohydrates, K, Ca, and proline in treated plants during prolonged irrigation intervals as well as saline shock conditions. There were also increases in the antioxidant defensive mechanisms such as catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and non-enzymatic antioxidants as well as reduced lipid peroxidation. The application of SWE at 7 mL·L−1 showed higher performance in treated plants during prolonged irrigation intervals as well as saline conditions. Our findings imply that several mechanisms including drought tolerance, osmotic adjustment and antioxidant defense system may interact to enhance the performance of plants in the face of environmental stress following SWE treatments

Evaluation of Silicon Supplementation for Drought Stress under Water-Deficit Conditions: An Application of Sustainable Agriculture

Drought is a key abiotic stress that confines agriculture development worldwide. Silicon (Si) is commonly considered to be a valuable element for resistance against drought and for sustainable agriculture. To investigate the morpho-physiological and biochemical characteristics of Gerbera jamesonii plants, a pot experiment was conducted under greenhouse conditions and exposed to water stress (60% FC) and well-watered (100% FC) conditions. Foliar application of Si was carried out after ten days (48 days after sowing) of drought treatment and was repeated weekly, while well-water was regarded as control. Water deficiency significantly abridged the morphological attributes, pigments, and stress-related metabolites and negatively affected the photosynthetic apparatus in drought-stressed gerbera plants. However, Si supplementation by 40 mg L-1 produced increased leaf area (31%), stem length (25%), flower diameter (22%), plant fresh biomass (17%), total chlorophyll (48%), and concentration of carotenoids (54%) in water-stressed plants. Similarly, the accretion of a total free amino acid (41%) and the activities of peroxidase, catalase, superoxide dismutase, ascorbate peroxidase, glycinebetaine, total soluble proteins, total free proline, and malondialdehyde were enhanced by 44%, 31%, 53%, 33%, 330%, 61%, 51%, and 66%, respectively, under drought stress in comparison with control conditions. Meanwhile, the photosynthetic rate (89%), the transpiration rate (12%), and stomatal conductance (55%) were significantly enhanced in water-deficit gerbera leaves with Si supplementation. This study proposes that the foliar application of Si is a viable and convenient method of improving the performance of elegant gerbera flower plants in regions of the world that are facing severe water deficiency

IBD risk loci are enriched in multigenic regulatory modules encompassing putative causative genes.

GWAS have identified >200 risk loci for Inflammatory Bowel Disease (IBD). The majority of disease associations are known to be driven by regulatory variants. To identify the putative causative genes that are perturbed by these variants, we generate a large transcriptome data set (nine disease-relevant cell types) and identify 23,650 cis-eQTL. We show that these are determined by ∼9720 regulatory modules, of which ∼3000 operate in multiple tissues and ∼970 on multiple genes. We identify regulatory modules that drive the disease association for 63 of the 200 risk loci, and show that these are enriched in multigenic modules. Based on these analyses, we resequence 45 of the corresponding 100 candidate genes in 6600 Crohn disease (CD) cases and 5500 controls, and show with burden tests that they include likely causative genes. Our analyses indicate that ≥10-fold larger sample sizes will be required to demonstrate the causality of individual genes using this approach

Seroprevalence and real-time PCR study of Epstein-Barr virus and the value of screening in pretransplant patients

Objective This study was performed to estimate the prevalence of Epstein-Barr virus immunoglobulin M virus capsid antigen (EBV IgM VCA) among healthy blood donors and to confirm the real risk of transfusion transmission by detection of virus load using PCR quantification. Materials and methods A total of 860 apparently healthy Egyptian blood donors were enrolled and tested for EBV IgM VCA. Quantitative PCR was performed for reactive cases for EBV IgM VCA. Results An overall 38 patients were reactive for EBV IgM VCA, constituting 4.4% of the sample. Reactivity of Epstein-Barr virus did not differ significantly as regards sex distribution, blood grouping, Rh factor positivity, and hemoglobin level, but it was significantly higher among upper Egypt participants than among those from other regions (P = 0.006). There was a very high statistically significant positive correlation between the titer of EBV VCA IgM reactive cases and age in the studied group (P = 0.0001 and r = 0.6). PCR was negative for all of the reactive cases. Conclusion Routine screening for Epstein-Barr virus in blood bags is not economical. Screening is highly recommended only for immunocompromised and pretransplant patients. Viremia is not the role in individuals with EBV IgM positive sera, which in turn changes some concepts in organ transplantation

Salicylic Acid-Regulated Antioxidant Mechanisms and Gene Expression Enhance Rosemary Performance under Saline Conditions

Salinity stress as a major agricultural limiting factor may influence the chemical composition and bioactivity of Rosmarinus officinallis L. essential oils and leaf extracts. The application of salicylic acid (SA) hormone may alleviate salinity stress by modifying the chemical composition, gene expression and bioactivity of plant secondary metabolites. In this study, SA was applied to enhance salinity tolerance in R. officinallis. R. officinallis plants were subjected to saline water every 2 days (640, 2,000, and 4,000 ppm NaCl) and 4 biweekly sprays of SA at 0, 100, 200, and 300 ppm for 8 weeks. Simulated salinity reduced all vegetative growth parameters such as plant height, plant branches and fresh and dry weights. However, SA treatments significantly enhanced these plant growth and morphological traits under salinity stress. Salinity affected specific major essential oils components causing reductions in α-pinene, β-pinene, and cineole along with sharp increases in linalool, camphor, borneol, and verbenone. SA applications at 100–300 ppm largely reversed the effects of salinity. Interestingly, SA treatments mitigated salinity stress effects by increasing the total phenolic, chlorophyll, carbohydrates, and proline contents of leaves along with decline in sodium and chloride. Importantly, this study also proved that SA may stimulate the antioxidant enzymatic mechanism pathway including catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) as well as increasing the non-enzymatic antioxidants such as free and total ascorbate in plants subjected to salinity. Quantitative real-time PCR analysis revealed that APX and 3 SOD genes showed higher levels in SA-treated rosemary under salinity stress, when compared to non-sprayed plants. Moreover, the expression level of selected genes conferring tolerance to salinity (bZIP62, DREB2, ERF3, and OLPb) were enhanced in SA-treated rosemary under salt stress, indicating that SA treatment resulted in the modulation of such genes expression which in turn enhanced rosemary tolerance to salinity stress