SYNTHESIS AND ANTIVIRAL ACTIVITY OF NOVEL ETHYL 2-(3-HETEROCYCLE-1H-INDOL-1-YL) ACETATE DERIVATIVES

Objective: Marek's disease (MD) is a widespread, herpesvirus-induced neoplastic disease in the domestic chicken that is caused by Marek's disease virus (MDV). Marek’s disease virus (MDV) belongs to the alphaherpesvirus family such as Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2). Recently Bag and co-workers 2014 reported that, 7-methoxy-1-methyl-4, 9-dihydro-3H-pyrido [3, 4-b]indole (Harmaline) showed potent anti-HSV-1 activity against both wild type and clinical isolates of HSV-1. The present work aimed to synthesize some new heterocyclic systems incorporated to indole moiety starting from ethyl 2-(3-acetyl-1H-indol-1-yl)acetate (1) in order to evaluate their antiviral activity in a trail to explore potential antiviral agents against MDV to limit the disease course and losses. Methods: Reaction of ethyl 2-(3-acetyl-1H-indol-1-yl) acetate (1) with semicarbazide hydrochloride yielded semicarbazone derivative 2. The oxidative cyclization of 2 using thionyl chloride and selenium dioxide afforded 1, 2, 3-thia and 1, 2, 3-selenadiazole derivatives 3 and 4, respectively. On the other hand, reaction of 1 with 4-chloro and 4-nitrobenzaldehydes under Claisen-Schmidt conditions gave α, β-unsaturated keto derivatives 5a, b. Cyclization of 5a, b using hydrazine hydrate, phenyl hydrazine, urea, thiourea or guanidine led to the formation of pyrazoles 6a, b, 7a, b, and pyrimidines derivatives 8a, b-10a, b; respectively. Condensation of 1 with phenyl hydrazine followed by Vilsmeier Haack formylation gave pyrazole-4-carboxaldehyde derivative 12. Reaction of aldehydic function group of 12 with different reagents led to the formation of pyrazol-5-ones 14-16, thiazolidinone 18, aziditine 19, 1, 6-diaminopyridine 21, triazolo(1, 5-a)pyridine 22 and pyrano(2, 3-c) pyrazole derivatives 23. The in vitro antiviral activity of the selected compounds 6a, b 7a, b 8a, b 9a, b and 10a, b was studied against Marek's disease virus (MDV). Results: Chicken embryo experiment showed that compounds 7b, 8b, 9b and 10a possessed significant antiviral activity with IC50 ranged between 5 and 6 µg/ml and substantial therapeutic indices (TI) of 80 and 83 were recorded. Cytotoxicity assay indicated that CC50 of 7b, 8b, 9b and 10 were greater than 400 and 500 mg/ml. Conclusion: Compounds 7b, 8b, 9b and 10a showed promising effect as anti-MDV infectivity application

Laboratory assessment and durability performance of vinyl-ester, polyester, and epoxy glass-FRP bars for concrete structures

In the last decade, noncorrosive glass fiber-reinforced-polymer (GFRP) bars have become more widely accepted as cost-effective alternatives to steel bars in many applications for concrete structures (bridges, parking garages, and water tanks). Also, these reinforcing bars are valuable for temporary concrete structures such as soft-eyes in tunneling works. The cost of the GFRP bars can be optimized considering the type of resin according the application. Yet limited research seems to have investigated the durability of GFRP bars manufactured with different types of resin. In this study, the physical and mechanical properties of GFRP bars made with vinyl-ester, isophthalic polyester, or epoxy resins were evaluated first. The long-term performance of these bars under alkaline exposure simulating a concrete environment was then assessed in accordance with ASTM D7705. The alkaline exposure consisted in immersing the bars in an alkaline solution for 1000, 3000 and 5,000 h at elevated temperature (60oC) to accelerate the effects. Subsequently, the bar properties were assessed and compared with the values obtained on unconditioned reference specimens. The test results reveal that the vinyl-ester and epoxy GFRP bars had the best physical and mechanical properties and lowest degradation rate after conditioning in alkaline solution, while the polyester GFRP bars evidenced the lowest physical and mechanical properties and exhibited significant degradation of physical and mechanical properties after conditioning

Reinforced Concrete Foundation Remote Monitoring

BDV34-977-09Date on cover: January 2019This project investigated whether it is possible to remotely monitor reinforced concrete foundations for the purpose of corrosion detection. The focus of the project was on identifying and investigating a technology that could provide both the delivery of energy to, and communications with, embedded sensors without the additional installation of wiring. A radio frequency propagation technique that uses the reinforcing steel as a single wire transmission line was identified as the most appropriate candidate, and experiments were designed to determine its usefulness. Baseline experiments conducted at 2.4 GHz in air were successful and demonstrated that the designed interfacing couplers and impedance matching circuits were adequate. However, when the medium was changed to concrete, the attenuation was too severe to support either energy harvesting or communications. Reducing the operating frequency to 8 kHz and modifying the interface provided only slight improvement. Given the successful results when operated in air, it may be possible to transfer the technology to monitoring existing open-air steel structures such as bridges and towers. In addition, it may be possible to adapt the approach for use in reinforced concrete foundations that include concentric reinforcing steel structures that could be used as a two-wire circuit for both energy harvesting and communications

Using finite element analysis to evaluate the performance of cracked bridge decks

Transverse cracks frequently develop on concrete bridge decks. The materials used at this time to fill and seal the transverse, longitudinal, and other cracks on bridge decks have an elongation factor of 10%. It has been observed that once applied and cured, the crack filling material fails once loads are applied and deflections occur. Once the filling material fails, it becomes partially functional only, and in many instances water or moisture penetrates the crack again. An experimental study for the FDOT had been completed to better understand the performance of four different types of sealant materials and their structural performance. This research utilizes finite element methods to model and simulate the behavior of the tested bridge deck without the crack filling materials. Three-dimension finite-element (FE) models for the decks were developed using ANSYS. The models were used to evaluate behavior of deck before cracks were formed to identify crack formation and propagation. Cracked decks without sealing fills were also modeled and analyzed to investigate the performance of the decks after cracking. The models were utilized to study the mechanism of crack development. Computational results were compared to experimental results and are in good agreement. The models will be used to examine alternate methods of controlling or preventing cracking and to study the effects of different load patterns, load magnitudes, deflection limits, bridge span length, bridge continuity, and structural system (simply supported and continuous spans). © ASCE 2012

Extended Strut-and-Tie Model for Punching-Shear Strength of Fiber-Reinforced Polymer-Reinforced Concrete Edge-Slab Column Connections

Fiber-reinforced polymer (FRP) bars have emerged as a pioneering solution to eliminate the corrosion problems associated with conventional steel bars in aggressive environments. Glass fiber-reinforced polymer (GFRP) bars are now extensively used as internal reinforcing because they are more cost-effective than other types of FRP bars. This paper presents a new design model—namely, the extended strut-and-tie model (STM)—to predict the punching-shear strength of edge slab-column (ESC) connections entirely reinforced with FRP bars. The proposed model was developed based on the failure criteria of the strut-and-tie method for symmetric punching in conjunction with an interactive approach to describe asymmetric punching-shear behavior due to moment transfer in FRP-reinforced concrete ESC connections. The extended STM is appropriate for normal-strength concrete (NSC) and high-strength concrete (HSC) ESC connections reinforced with FRP bars. The connections tested by the authors and others found in the literature were used to evaluate the proposed model. The extended STM yielded safe predictions compared with the experimental ones, giving average experimental-to-predicted punching-shear strengths of 1.19 ± 0.13 and coefficient of variation of 10.86%. Furthermore, the proposed model achieved higher accuracy and narrower scatter for punching-shear strength predictions than the equations in ACI 440.1R-15, CSA S806-17, and JSCE-97

Evaluation of the flexural strength and serviceability of concrete beams reinforced with different types of GFRP bars

The current available glass-fiber-reinforced polymer (GFRP) bars have a modulus of elasticity ranges from 40 to 60 GPa in accordance with CSA S807-10 Canadian standard. The surface profile of GFRP bars, however, can be smooth, sand-coated, deformed, grooved, or ribbed. This study aimed at investigating the flexural behavior and serviceability performance of concrete beams reinforced with different types of GFRP bars. The test parameters were: (i) modulus of elasticity (46.4–69.3 GPa); (ii) surface profile (sand-coated and helically-grooved), and (iii) reinforcement ratio. The study included testing of 17 full-scale beams measuring 4,250 mm long × 200 mm wide × 400 mm deep reinforced with GFRP bars. The test results are presented and discussed in terms of deflection, crack width, strain, and load-carrying capacity. The cracking behavior of the tested beams tends to confirm that sand-coating of GFRP bars enhances the bond performance in concrete more than the helically-grooved profile. The curvature limit of 0.005/d seems to be feasible in controlling the serviceability of GFRP-reinforced concrete (GFRP-RC) beams. In addition, ACI 440.1R-06 and ACI 440.1R-15 underestimated the deflection, while ISIS M-03 and CSA S806-12 provided conservative deflection values at 0.30 of nominal moment capacity, Mn

Use of basalt fibers for concrete structures

This study investigated the use of basalt fiber bars as flexural reinforcement for concrete members and the use of chopped basalt fibers as an additive to enhance the mechanical properties of concrete. The material characteristics and development length of two commercially-available basalt fiber bars were evaluated. Test results indicate that flexural design of concrete members reinforced with basalt fiber bars should ensure compression failure and satisfying the serviceability requirements. ACI 440.1R-06 accurately predicts the flexural capacity of members reinforced with basalt bars, but it significantly underestimates the deflection at service load level. Use of chopped basalt fibers had little effect on the concrete compressive strength; however, significantly enhanced its flexural modulus

Facile synthesis of microporous sulfur-doped carbon spheres as electrodes for ultrasensitive detection of ascorbic acid in food and pharmaceutical products

Fabrication of electrodes based on a metal-free catalyst with desirable sensitivity, selectivity, and stability has been given considerable interest. Microporous sulfur-doped carbon microspheres (S-MCMS) were synthesized and assembled as an electrochemical sensor for the monitoring of ascorbic acid (AA) in commercial juices and vitamin C tablets. The S-doped microporous carbon with a spherical structure was fabricated at different annealing temperatures (700, 800, and 900 °C) to achieve a high surface area, an actively doped carbon interfacial surface, soft interactive surfaces and an open microporous network. The high surface area, actively doped S-atom percentage, microporous construction, and active doping of the carbon microsphere construction of S-MCMS-900, make it a highly stable metal-free electrocatalyst for selective detection of AA. The S-atoms incorporated with the sp2-carbon matrix form numerous active sites, which bind to targets and stimulate the transduction of the electrochemical interaction with a fast response and high charge transfer efficiency. Selective monitoring of AA on S-MCMS-900 with high sensitivity was achieved with a detection limit as low as 1 μM, and wide linear range up to 4 mM. Monitoring of AA in lemon juice or pharmaceutical tablets was realized by using S-MCMS-900, with a fast response, high sensitivity, reliable selectivity, high stability and rational reproducibility. S-MCMS-900 can be employed as a fast, sensitive, and selective assay for routine detection of AA in food, biological, and environmental samples