Effects of different coatings, primers and additives on corrosion of steel rebars

In this research, methods of increasing the corrosion resistance of reinforced concrete were experimentally investigated. The study used silica fume and fly ash at optimized percentages of 10 and 25% by cement weight, polypropylene fibers at a ratio of 2.5% by volume of concrete, and a commercial corrosion inhibitor, 2-dimethylaminoethanol (Ferrogard 901), at 3% by cement weight. The corrosion resistance of three types of reinforcements, mild steel (STt37), AISI 304 stainless steel, and AISI 316 stainless steel, was investigated. The effects of various coatings, including hot-dip galvanizing, alkyd-based primer, zinc-rich epoxy primer, alkyd top coating, polyamide epoxy top coating, polyamide epoxy primer, polyurethane coatings, a double layer of alkyd primer and alkyd top coating, and a double layer of epoxy primer and alkyd top coating, were evaluated on the reinforcement surface. The corrosion rate of the reinforced concrete was determined through results of accelerated corrosion and pullout tests of steel-concrete bond joints and stereographic microscope images. The samples containing pozzolanic materials, the corrosion inhibitor, and a combination of the two showed significant improvement in corrosion resistance by 7.0, 11.4, and 11.9 times, respectively, compared to the control samples. The corrosion rate of mild steel, AISI 304, and AISI 316 decreased by 1.4, 2.4, and 2.9 times, respectively, compared to the control sample; however, the presence of polypropylene fibers reduced the corrosion resistance by 2.4 times compared to the control

Estimation of Monthly Total Dissolved Solids Using ANN and LS-SVM Techniques in the Aji Chay River, Iran

This research follows on from diverse international efforts to safeguard one of the largest natural lakes in the world, Urmia lake in North West Iran. In this research two new numerical packages based on Artificial Neural Networks (ANN) and the Least Square Support Vector Machine (LS-SVM) models were developed to estimate monthly Total Dissolved Solid (TDS) in the Aji Chay River, one the main tributaries of Urmia lake, Iran. A feed forward back propagation (FFB) model was used to obtain a set of coefficients for a linear model, and the radial basis function (RBF) kernel was employed for the LS-SVM model. The input data sets of both the ANN and LS-SVM models consists of six water quality parameters: TDS, Mg2+, Na+, Ca2+, Cl-, and SO4 2-, all collected on a monthly time scale over a period of 30 years from the Vanyar and Zarnagh stations, in the Aji Chay watershed. The research demonstrated that both models can effectively predict the variability of TDS, but for the Vanyar station with the ANN model (giving an R2 value of 0.913 and RMSE of 0.0032, a Nash-Sutcliffe Efficiency (NSE) coefficient 0.812 and as such has a more efficient and accurate estimation when compared to the LS-SVM model with R2=0.871 and RMSE =0.097 and NSE=0.86. The analysis of Zarnagh station data shows R2=0.853 and RMSE=0.0162, NSE= 0.854 for SVM and R2=0.903 and RMSE =0.0091 and NSE=0.85 for ANN

Frequency of Oral and Maxillofacial Tumors in the Samples Referred to the Pathology Department of Qazvin University of Medical Sciences

Introduction: The mouth, jaw, and face are prone to oral and maxillofacial tumors, constituting a significant proportion of pathological lesions in Iran. Therefore, the present study aimed to investigate the frequency of oral and maxillofacial tumors in the samples referred to the Pathology Department of Qazvin University of Medical Sciences.Materials and Methods: This cross-sectional descriptive study was performed on 110 patients referred to Qazvin Dental Clinic with pathological diagnosis of oral and maxillofacial tumors. After reviewing the medical files, information on tumor type, anatomical location, tissue origin, age range, gender, smoking and drug use, alcohol consumption, family history, and pathological diagnosis were extracted. The data were analyzed in SPSS software (version 25).Results: According to the findings of the study, 58.18% of women and 41.81% of men developed tumors of the mouth, jaw, and face. These pathological lesions were in the age range of 9-90 years (mean age of 41.04±20.29 years). They made up 42.72% of benign tumors and 57.27% of malignant ones. Among these, 84 cases were odontogenic tumors, and 26 cases were non-odontogenic tumors.Conclusion: As evidenced by the obtained results, oral squamous cell carcinoma was the most common among Oral and Maxillofacial tumors. This finding is consistent with the results of many epidemiological studies in the field of tumors of the mouth, jaw, and face

The Effects of Vestibular Stimulations on Neurodevelopment, Growth and Vital Signs of Preterm Infants: A Systematic Review

Background: The purpose of the present study was to systematically review all published studies investigating the effects of only vestibular interventions on neurodevelopment, growth and vital signs in preterm infants (PIs).Method: PubMed, SCOPUS, Web of Science, CINAHL and EMBASE databases were searched to find relevant studies published from 1980 and June 2022. In addition, reference lists of the articles were also checked.Results: Twenty articles met the inclusion criteria. Fifteen of these articles reported studies conducted on stable preterm infants and five on unstable ones. Waterbed, rocking, hammock, air mattress and Vestibu_Guide stimulations were applied in eight, four, six, one, and one study, respectively. Twelve studies evaluated neurobehavioral development, five studies assessed neuromotor development, five studies evaluated the growth and fifteen studies assessed the vital signs in preterm infants using vestibular stimulations.Conclusions: The results indicate that vestibular stimulations may improve neurodevelopment, growth and vital signs in premature infants, but there are still some disagreements among researchers, and further research is recommended

Calpeptin is a potent cathepsin inhibitor and drug candidate for SARS-CoV-2 infections

Several drug screening campaigns identified Calpeptin as a drug candidate against SARS-CoV-2. Initially reported to target the viral main protease (Mpro), its moderate activity in Mpro inhibition assays hints at a second target. Indeed, we show that Calpeptin is an extremely potent cysteine cathepsin inhibitor, a finding additionally supported by X-ray crystallography. Cell infection assays proved Calpeptin’s efficacy against SARS-CoV-2. Treatment of SARS-CoV-2-infected Golden Syrian hamsters with sulfonated Calpeptin at a dose of 1 mg/kg body weight reduces the viral load in the trachea. Despite a higher risk of side effects, an intrinsic advantage in targeting host proteins is their mutational stability in contrast to highly mutable viral targets. Here we show that the inhibition of cathepsins, a protein family of the host organism, by calpeptin is a promising approach for the treatment of SARS-CoV-2 and potentially other viral infections

Massive X-ray screening reveals two allosteric drug binding sites of SARS-CoV-2 main protease

The coronavirus disease (COVID-19) caused by SARS-CoV-2 is creating tremendous health problems and economical challenges for mankind. To date, no effective drug is available to directly treat the disease and prevent virus spreading. In a search for a drug against COVID-19, we have performed a massive X-ray crystallographic screen of repurposing drug libraries containing 5953 individual compounds against the SARS-CoV-2 main protease (Mpro), which is a potent drug target as it is essential for the virus replication. In contrast to commonly applied X-ray fragment screening experiments with molecules of low complexity, our screen tested already approved drugs and drugs in clinical trials. From the three-dimensional protein structures, we identified 37 compounds binding to Mpro. In subsequent cell-based viral reduction assays, one peptidomimetic and five non-peptidic compounds showed antiviral activity at non-toxic concentrations. Interestingly, two compounds bind outside the active site to the native dimer interface in close proximity to the S1 binding pocket. Another compound binds in a cleft between the catalytic and dimerization domain of Mpro. Neither binding site is related to the enzymatic active site and both represent attractive targets for drug development against SARS-CoV-2. This X-ray screening approach thus has the potential to help deliver an approved drug on an accelerated time-scale for this and future pandemics

X-ray screening identifies active site and allosteric inhibitors of SARS-CoV-2 main protease

The coronavirus disease (COVID-19) caused by SARS-CoV-2 is creating tremendous human suffering. To date, no effective drug is available to directly treat the disease. In a search for a drug against COVID-19, we have performed a high-throughput X-ray crystallographic screen of two repurposing drug libraries against the SARS-CoV-2 main protease (M^(pro)), which is essential for viral replication. In contrast to commonly applied X-ray fragment screening experiments with molecules of low complexity, our screen tested already approved drugs and drugs in clinical trials. From the three-dimensional protein structures, we identified 37 compounds that bind to M^(pro). In subsequent cell-based viral reduction assays, one peptidomimetic and six non-peptidic compounds showed antiviral activity at non-toxic concentrations. We identified two allosteric binding sites representing attractive targets for drug development against SARS-CoV-2

Optimized alkali-activated slag-based concrete reinforced with recycled tire steel fiber

This study employed Taguchi-Grey relational analysis to optimize the influences of binder content, the molarity of sodium hydroxide (SH) solution, alkaline solution to binder content (Al/Bi) ratio, water to alkali-activated solids (W/S) ratio, and sodium silicate to sodium hydroxide solution (SS/SH) ratio on the workability, setting time, and compressive strength of alkali-activated slag-based concrete (AASC). Then, the recycled tire steel fibers (RTSF) were introduced into the optimized mixture in different dosages, and the physical and mechanical properties of fiber-reinforced AASC (FR-AASC) were evaluated. RTSF inclusion negatively affected the workability and increased the density while slightly reducing the water absorption. Additionally, the compressive strength and flexural behavior of FR-AASC improved by increasing the RTSF content. The analysis of images taken from flexural specimens through the Digital Image Correlation technique (DIC) revealed that higher RTSF dosage caused a curved macro crack with several branches alongside, leading to a better post-cracking performance in terms of strength and toughness

Effects of Diethanolamine (DEA) and Glass Fibre Reinforced polymer (GFRP) on setting time and mechanical properties of shotcrete

© 2020 Elsevier Ltd By now, various accelerators have been used to accelerate the chemical reactions between cement and water to achieve a desired strength. This study investigates the effects of diethanolamine (DEA) as a less corrosive accelerator on the setting time and mechanical properties of fibre reinforced shotcrete (FRS). Glass fibre reinforced polymer (GFRP) was also used to improve the flexural and tensile strengths of shotcrete. In total, 76 different mix designs were prepared and tested to determine the setting time, flexural and tensile strength of shotcrete. The mixes were designed based on three influential parameters including GFRP, water/cement (w/c) ratio and the amount of DEA. According to the results, the flexural and tensile strengths of all specimens increased by adding 0.5% of the weight of GFRP. However, both tensile and flexural strengths showed an insignificant reduction by adding DEA to the mixes. The tensile and flexural strengths of specimens decreased slightly by adding DEA in the presence of GFRP. At a certain amount of DEA, the setting time increased twice with increasing the w/c ratio. The results showed a reduction in the shotcrete strength by using DEA. Thus, in the case where both the setting time and shotcrete strength are of great importance, the optimal DEA level is close to 0.3% of the dry weight of cement and 0.5% GFRP