Corrosion behaviour of coatings on 304 steel

The aim of this study is to determine the corrosion characteristics of 304 steel by the methods of Tafel extrapolation, linear polarization and electrochemical impedance spectroscopy (EIS). The steel surface is covered with nickel as electrochemical Watt's bath. Additionally, polyaniline (PANI) is synthesized on the steel electrode covered with nickel by the method of electrochemical cyclic voltammetry method. The effect of single and double coats of steel on corrosion resistance is examined in 3.5 % NaCl, 1N NaOH and 1N HCl solutions for the waiting time of 1, 48, 120 and 168 h. The surface morphology of steel, which is uncovered, is examined by SEM-EDX and the polyaniline is also examined in the same way. As well as the one covered with Ni + polyaniline is examined in the same way too. The synthesized polyaniline on the surface is analyzed by FTIR spectrum. Double coatings (Ni + polyaniline) has showed better corrosion resistance than single coating (polyaniline). Ni + polyaniline coatings in 1 N NaOH and 1 N HCl solutions has showed better corrosion resistance than polyaniline coating. The corrosion current of the steel covered with Ni + polyaniline in 1 N HCl and 1 N NaOH solutions is lower than the corrosion current of polyaniline coating. SEM-EDX analyses have showed that the surface covered with Ni + polyaniline is more homogenous and compact. This result is also convenient with the electrochemical experiment results

In vitro biological activities of potassium metaborate; antioxidative, antimicrobial and antibiofilm properties

Antioxidant, antimicrobial and antibiofilm activities of potassium metaborate (KBO2) was investigated within the present study. Antioxidant capacity of potassium metaborate was determined by β-carotene bleaching (BCB) assay and hydroxyl radical scavenging activity. Potassium metaborate was evaluated for its antimicrobial effects against selected Gram-positive bacteria, Gram-negative bacteria and a yeast via broth dilution method. The inhibition capability of potassium metaborate on the microbial biofilm formation of tested microorganisms was measured by microplate biofilm method using MTT (3- [4, 5- dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium-bromide). Biofilm inhibition capacity of potassium metaborate was also observed by Scanning Electron Microscope (SEM). Potassium metaborate was found to have the ability to scavenge hydroxyl radicals with an inhibition rate of 71.13% at 100 mM concentration. Antioxidant activity of potassium metaborate as determined by BCB assay gave higher result with an inhibition rate of 86.96% at the same concentration. According to the MIC (minimum inhibition concentration) values, the potassium metaborate inhibited the growth of C. albicans, S. aureus and E. coli at 62.5 mM concentrations while it was 31.25 mM for B. subtilis and 125 mM for P. aeruginosa. The highest antibiofilm activity was determined at the MIC of potassium metaborate with the reduction rate of 90.18% against C. albicans. It was concluded that, potassium metaborate have strong biological activities and can be effectively used for biomedical and environmental solutions

Antibiofilm Evaluation of Two Different Denture Liners Incorporated with Zirconium Oxide Nanoparticles

Abstract Objectives: This in vitro study was purposed to examine the effects of incorporation nano-ZrO2 on antibiofilm activity, glucose sorption, weight change, and surface roughness of two different types of denture liners. Materials and Methods: Modified nano-ZrO2 were added to silicone-based and acrylic resin-based prosthetic lining materials at two different concentrations (0.5% and 1%). The antibiofilm potentials of test groups against Candida albicans (C. albicans), Staphylococcus aureus (S. aureus), and Streptococcus mutans (S. mutans) were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) method. Surface roughness, weight change, and glucose sorption of denture liners were also evaluated after modifying with nano-ZrO2. Results: According to the antibiofilm activity results, 1% nano-ZrO2 addition to silicon-based and acrylic resin-based denture liners resulted in 16.48% and 13.39% of biofilm inhibition for S. aureus, respectively. 1% nano-ZrO2 addition to silicon-based denture liners also inhibited the S. mutans biofilm formation at an 8.16% rate. Nano-ZrO2 addition to the test groups had no inhibition effect on C. albicans biofilm formation. Surface roughness decreased significantly once nano-ZrO2 was added in tissue conditioner test groups (p=0.012), however, the addition of 0.5% nano-ZrO2 increased soft denture liner test group significantly (p<0.001). Conclusions: To overcome the microbial biofilm problems (especially against S. aureus and S. mutans) caused by the use of denture liners, addition of nano-ZrO2 might be a promising agent with its antibiofilm capacities

Different features of lung involvement in Niemann-Pick disease and Gaucher disease

SummaryBackgroundNiemann-Pick disease (NPD) and Gaucher disease (GD) are well-known lysosomal storage diseases. Respiratory system involvement is an important cause of morbidity and mortality in patients with NPD and GD.ObjectivesWe tried to assess the clinical, radiological, and histological features of GD and NPD patients with lung involvement.MethodsWe reviewed medical history, physical examination, radiological, and histological data of 10 NPD and 7 GD patients.ResultsThe most common respiratory symptoms were recurrent lung infection and dyspnea. Although lung examination results in 6 NPD patients were normal, they had lung involvement; 3 patients were diagnosed as NPD directly via lung biopsy during investigation of recurrent lung infection or interstitial lung disease. All GD patients but 1 had respiratory system symptoms at the time of diagnosis. Hepatopulmonary syndrome was present in 4 GD patients. A ground-glass pattern and atelectasis were 2 important high-resolution computed tomography features in the NPD and GD patients. Flexible bronchoscopy and bronchoalveolar lavage were used for emergency extraction of bronchial casts in 1 NPD patient.ConclusionsLung involvement in NPD and GD patients should be included in the differential diagnosis of interstitial lung disease. Besides interstitial appearance on HRCT, atelectasis related to bronchial cast and bronchiectasis are other radiological findings in these group of patients. Analysis of bronchoalveolar fluid and lung biopsy provide very important clues for diagnosis. Hepatopulmonary syndrome is an important vascular complication observed in GD patients

Mentha longifolia (L.) ssp. Longifolia uçucu yağı: Gıda katkı maddesi olarak doğal antioksidan ve antimutajen kaynağı

This research was performed to control the antioxidant activity, mutagenicity and antimutagenic effect of Mentha longifolia (L.) ssp. longifolia essential oil (EO), which is considered as a possible ingredient when producing healthy food. The antiradical activity was established using DPPH (2,2-diphenyl-1- picrylhydrazyl radical) and β-carotene/linoleic acid bleaching assays. The total phenolic content in the EO was evaluated by Folin Ciocalteau method (FCR). Ames Salmonella/microsome mutagenicity assay was applied to detect possible mutagenic and antimutagenic behavior. Our observations reveal that the IC50 value for DPPH radicals was 5.27 ± 0.13 mg/mL. The total antioxidant efficiency increased with an increase in the concentration of the EO, and IC50 value 11.7 ± 0.21 mg/mL. The total of phenolics was 186 ± 8.9 mg/g gallic acid equivalent/EO. Also, any concentrations of the EO used did not show mutagenic action but exhibited strong antimutagenic effects at 10.0-4.0 µg/plate concentrations. This research proposes that because of the antioxidant and antimutagenic characteristics, the EO is very advantageous and significant to the company’s manufacturing food additives.Bu araştırma sağlıklı yiyecek üretirken olası bir katkı maddesi olarak düşünülen Mentha longifolia (L.) ssp. longifolia uçucu yağının (EO) antioksidan aktivitesi, mutajenitesi ve antimutajenik etkisini kontrol etmek için gerçekleştirilmiştir. Antiradikal aktivite DPPH (2,2-diphenyl-1-picrylhydrazyl radical) yöntemi ile ve β-karoten/linoleik asit ağartma tayini kullanılarak belirlenmiştir. Uçucu yağın toplam fenolik madde içeriği Folin Ciocalteau metodu (FCR) ile tahmin edilmiştir. Olası mutajenik ve antimutajenik davranışını belirlemek için Ames Salmonella/mikrozom mutajenite testi uygulanmıştır. Gözlemlerimiz DPPH radikalleri için IC50 değerinin 5.27 ± 0.13 mg/mL olduğunu açığa çıkarmıştır. Total antioksidan etkinliği uçucu yağ konsantrasyonunun artmasıyla artmıştır ve IC50 değeri 11.7 ± 0.21 mg/mL’dir. Toplam fenolik madde içeriği 186 ± 8.9 mg/g gallik asit eşdeğeri/uçucu yağ’dır. Ayrıca uçucu yağın herhangi bir konsantrasyonu mutajenik etki göstermemiştir, fakat 10.0-4.0 µg/plate konsantrasyonlarında güçlü antimutajenik etki göstermiştir. Bu araştırma antioksidan ve antimutajenik özelliklerinden dolayı EO’nun gıda katkı maddesi üreten şirketler için çok avantajlı ve önemli olduğunu göstermektedir

Burkholderia multivorans SB6 lipase as a detergent ingredient: characterization and stabilization

WOS: 000367541300005In this study, 265 bacterial isolates were collected from kitchen wastewater samples using Rhodamine B agar medium. Of these, 115 isolates were found to respond positively to the addition of commercial detergents. Using 16S rRNA sequence analysis, the isolate demonstrating the high stability towards commercial detergents was identified as Burkholderia multivorans. An SB6 lipase with a molecular mass of 70 kDa was purified from B. multivorans. The purified enzyme showed optimal activity at pH 9.0 and 40 A degrees C and remained stable in the presence of various metal ions, surfactants, and oxidizing agents. The addition of boron compounds improved the pH stability and thermostability of the enzyme, which displayed stability against some commercial detergents; moreover, this stability increased when boron compounds were added to the incubation medium as stabilizers. These properties make SB6 lipase an ideal choice as an additive in detergent formulations.TUBITAK, The Scientific and Technical Research Council of Turkey [TBAG-210T084]This study is a part of the Ph.D. work of Rukiye Boran. A part of this work was supported by TUBITAK, The Scientific and Technical Research Council of Turkey, through the grant number TBAG-210T084. We thank Dr. E. Sonay Elgin for help during the enzyme purification study. We would also like to express our gratitude to Dr. Omer Simsek for their kind help during the identification of bacterial strain

Production and characterization of a cold-active and n-hexane activated lipase from a newly isolated Serratia grimesii RB06-22

WOS: 000340296700004A lipase-producing bacterium isolated from raw milk was identified as Serratia grimesii based on 16S rRNA sequence analysis. The extracellular lipase was partially purified by ammonium sulfate precipitation and ultrafiltration. Maximal activity was observed at 10 degrees C, the optimum pH was 8.0 and the enzyme was stable at 5-30 degrees C for 1 h. The K-m and V-max values were 1.7 mM and 0.3 mM/min respectively. It was found that the lipase had the highest hydrolytic activity towards sunflower oil and soybean oil. CaCl2 had a stimulatory effect on lipase activity, while EDTA and iodoacetic acid slightly inhibited the lipase activity and the enzyme was strongly inhibited by PMSF. The enzyme was compatible with various non-ionic surfactants as well as sodium cholate and saponin. In addition, the enzyme was relatively stable towards oxidizing agents. This lipase exhibited maximum activity in 35% n-hexane retaining about 2191% activity for 1 h

Bio-Monitoring of heavy metal resistance in pseudomonas and pseudomonas related genus

The aim of present study was to determine the level of heavy metal resistance patterns and to determine if there is a relationship between heavy metal resistance and plasmid presence. From 28 identified strains, 39.3% corresponded to Stenotrophomonas maltophilia, 17.9% to Chryseomonas luteola, 14.3% to Pseudomonas fluorescens, 10.7% to Pseudomonas putida, 7.1% to Sphingomonas paucimobilis, 7.1% to Methylobacterium mesophilicum and 3.6% Pseudomonas stutzeri. The resistance of these Gram negative bacteria to 8 heavy metals, was investigated by agar dilution method. Most isolates showed tolerance to different concentrations of heavy metals, and minimal inhibition concentrations ranged from 0,005 mmol-1 -20 mmol-1 . All strains displayed high resistance to zinc and lead (100% and 96,4% respectively) and high susceptibility to silver, cobalt and mercury (92.9%, 92.9% and 96.4% respectively). M. mesophilicum strains were determined as the most resistant strains to studied heavy metals. Isolated bacteria were tested for the presence of plasmids using the modified hot alkaline lysis method. The study also demonstrated that about 17.8% of isolated bacteria carried 0.89-21.59 kb sized plasmids and metal resistance profiles of bacteria carrying the same plasmids were similar. This study reveals the heavy metal resistance profiles of non-aeruginosa Pseudomonas species and other related species and the association between the occurrence of plasmids and the resistance to heavy metals