Are antibacterial component additions in etchants and adhesives effective against Streptococcus Mutans?

The aim was to investigate the antibacterial activity of various acids and adhesives with and without antibacterial components against Streptococcus mutans. The antibacterial activities of 35% phosphoric acid (Ultra-Etch), 37% phosphoric acid with benzalkonium chloride (Etch-37), adhesive with chlorhexidine (Peak Universal Bond) and without any agent (PQ1) were investigated by agar-diffusion test. The inhibition-zones were measured after 48 h of incubation. For the tooth-cavity model test; cylindrical cavities were prepared on occlusal dentin surfaces of human molars and divided into four groups (n = 10 cavity/group). Group 1: Ultra-Etch + Peak Universal Bond, Group 2: Ultra-Etch + PQ1, Group 3: Etch-37 + PQ1 were applied. The fourth group without any agent application served as control. The teeth were immersed in 5.8 × 10⁶ cfu/ml of S. mutans solution to infect the cavities for 72 h before the application of the groups. After 72 h, dentin chips were collected from the cavity walls with burs for bacterial counting. Statistical analysis was performed by ANOVA, Bonferroni and Dunnett C tests (p < 0.05). Ultra-Etch and Etch-37 performed similar antibacterial activities in agar-diffusion test. Both acids showed better antibacterial activity compared to adhesives (p < 0.05). The antibacterial activity of PQ1 and Peak Universal Bond was observed to be inactivated by light-polymerization. According to the tooth-cavity model; Group I, II, and III demonstrated reduction in bacterial number and there was no significant difference between them. Antibacterial component additions in etchant and adhesive did not show superior antibacterial activity against S. mutans in both in vitro tests.     

Filter life comparison of different levels of nanofiber coated cleanable-surface filter for gas turbine

High-efficiency air filtration is a basic requirement for the most cost-effective operation of high-efficiency gas turbines. The filtration system protects the gas turbine from damaging debris. In gas turbine/dust collector applications, higher efficiency filtration could be achieved with nanofibers, which provide higher equipment protection than traditional media. With a nanofiber performance filter layer, the dust accumulates on the surface of the filtration media rather than within the media and could be cleaned off easily with a back pulse resulting in long filter life and a low-operating pressure drop. In this study five type of gas tribune nanofiber coated corrugated cellulose/synthetic filter media were developed. Nanofiber coating was adjusted for five filtration efficiency level, 50 ≤ E < 60, 60 ≤ E < 70, 70 ≤ E < 85, 85 ≤ E < 95 and 95 ≤ E, pore size and filter-life of the developed media were evaluated. One of the developed nanofiber coated media was also compared with two other commercial nanofiber coated gas tribune filter media, a glass fiber type filter media and a commercial fine fiber gas tribune filter media. It was seen that, with decreasing penetration levels due to nanofiber coating level, initial 30 cycle durations of filter life evaluation could reach about 229.9 to 250.7 min. Highest final cycle duration of 188.7 min belonged to cellulose/synthetic blend corrugated filter media with penetration of 13.66%. Nanofiber based surface filter media was cleaned up better than fine fiber media and final 30 cycle sequences were significantly higher. Surface of the nanofiber coated media was smoother when compared to fine fiber media and during the initial and final cycle test dust could not penetrate inside and could not hang to this smooth surface. So, with back pulse cleaning cake releasing have performed easily. It was also seen that, for higher filter life nanofiber coating should be uniform and robust to back pulse cleaning.     

A resampling-based Markovian model for automated colon cancer diagnosis

In recent years, there has been a great effort in the research of implementing automated diagnostic systems for tissue images. One major challenge in this implementation is to design systems that are robust to image variations. In order to meet this challenge, it is important to learn the systems on a large number of labeled images from a different range of variation. However, acquiring labeled images is quite difficult in this domain, and hence, the labeled training data are typically very limited. Although the issue of having limited labeled data is acknowledged by many researchers, it has rarely been considered in the system design. This paper successfully addresses this issue, introducing a new resampling framework to simulate variations in tissue images. This framework generates multiple sequences from an image for its representation and models them using a Markov process. Working with colon tissue images, our experiments show that this framework increases the generalization capacity of a learner by increasing the size and variation of the training data and improves the classification performance of a given image by combining the decisions obtained on its sequences.     

Selection of psychrotrophic Leuconostoc spp. from native fruits, and studies on their dextransucrases

Present study was aimed at selection of psychrotrophic Leuconostoc spp., having dextransucrase activity from native fruits and sauerkraut. Fifty-six colonies of lactic acid bacteria producing dextransucrase were isolated and characterized by physiological-biochemical methods. Seven isolates with high dextransucrase activities (0.68–1.63 IU/mL) were studied in detail including characterization by 16S rDNA sequence comparison. It was found that these isolates grow faster and produced dextransucrase earlier than Leuconostoc mesenteroides B512FMC-13Glc, a mutant form of the commercial strain. Molecular weights of the dextransucrases produced by 7 isolates were determined and acceptor reactions using maltose were studied. Dextranase hydrolysis products of dextrans produced by new enzymes were similar to those of commercially produced B-512 F dextran. The new dextransucrases could find industrial uses and the strains isolated (AN 39-1, Or2p-2, Mu3, and Mu10) could be used as prebiotic producing starters in food fermentations due to having high dextransucrase activity and their growth at 4°C.     

Sorption of heavy metal ions by glass beads-immobilized calix[4]arenes derivative

Glass beads (GB) immobilized, 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonylmethoxy-26,28-dihydroxycalix[4]arene (CA) are prepared and used as a new sorbent in sorption study of removal heavy metal ions. A calixarene derivative bonded to amino-functionalized glass beads sorbent was synthesized via a self assembly technique for sorbent of selected heavy metal ions in aqueous. In order to absorb selected heavy metal ions in aqueous, a calixarene derivative bonded to amino-functionalized glass beads sorbent was synthesized via a self assembly technique. The sorbent which is named GB-APTS-CA was characterized using infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), elemental analysis and thermal analysis (TGA/DTG). The influences of some experimental parameters including pH of the sample solution, weight of sorbent, concentration and temperature have been investigated. The sorption data were evaluated using the Langmuir, Freundlich and Dubinin Radushkevich (D-R) isotherm. The obtained maximum sorption capacity for Cu(II), and Pb(II) is 0.06 mmol g^?1 and 0.02 mmol g^?1, respectively. Thermodynamic parameters such as the standard free energy change (ΔG○), enthalpy change (ΔH○) and entropy change (ΔS○) were calculated to determine the nature of sorption process. Thus, GB-APTS-CA is favorable and useful for the removal of Cu(II) and Pb(II) metal ions.     

Phenolic composition,antioxidant, antibacterial,larvacidal against Culex pipiens,and cytotoxic activities of Hyacinthella lineata steudel extracts

This study reports the phenolic composition, antioxidant, antibacterial, larvacidal, and cytotoxic activity of methanol and acetone extracts of Hyacinthella lineata leaves and bulbs. The phenolic composition of H. lineata was determined by HPLC. The most abundant component was gallic acid (421.9µg/g). The β-carotene/DPPH/ABTS/FRAP decoloration method was used to estimate the total antioxidant activity. The total antioxidant activity was the highest for bulb-methanol fraction (65.41 ± 0.05%). The total phenolic content for leaves-methanol extract of the plant was determined as 6.56 ± 4.027mg/mL gallic acid equivalents. Analysis of the antibacterial activity showed that the methanolic-bulb extract are efficient against gram positive and gram negative bacteria. The cytotoxic effect on Artemia salina was assessed by Brine shrimp assay. Brine shrimp lethality assay showed that LC₅₀ values of HBM were obtained as 4.105 ± 2.42μg/ml. The bulb extract of H. lineata showed the highest larvicidal activity against Cx pipiens with value LC₅₀ (64.3275μg/ml). This study suggested that H. lineata may be used as a potential source of antioxidant, and for their biological activity, cytotoxic and antimicrobial properties.     

Novel structured gadolinium doped ceria based electrolytes for intermediate temperature solid oxide fuel cells

Novel three-layered intermediate temperature solid oxide fuel cell (SOFC) electrolytes based on gadolinium doped ceria (GDC) are developed to suppress the electronic conductivity of GDC, to improve the mechanical properties of the cell and to minimize power loss due to mixed conductive nature of GDC. Three different electrolytes are fabricated by sandwiching thin YSZ, ScSZ and ScCeSZ between two relatively thick GDC layers. An electrolyte composed of pure GDC is also manufactured for comparison. NiO/GDC and LSCF/GDC electrodes are then coated on the electrolytes by a screen printing route. SEM results show that it is possible to obtain dense and crack free thin layers of YSZ, ScSZ and ScCeSZ between two GDC layers without delamination. Performance measurements indicate that interlayered thin electrolytes act as an electronic conduction barrier and improve open circuit voltages (OCVs) of GDC based cells.     

The effect of learning analytics-based interventions in mobile learning on students' academic achievements,self-regulated learning skills,and motivations

Universal Access in the Information Society - This study examines the effects of using learning analytics (LA) in a mobile-based learning setting on students' self-regulated learning (SRL)...     

Investigation of thermal comfort properties of electrospun thermoplastic polyurethane fiber coated knitted fabrics for wind-resistant clothing

The integration of nanofibers into conventional fabrics may open up new opportunities such as improving the comfort performance and thermal management properties of outdoor clothing. Nanofibers are able to form a highly porous mesh and their large surface-to-volume ratio improves performance for many applications. This study shows the possible utility of the nanofiber coating on conventional knitted fabrics for improving the wind-resistance and breathability properties. It was seen that nanofiber coating did not cause a significant effect on water vapor and thermal resistance of electrospun thermoplastic polyurethane nanofiber coated cotton (CO), modal (CMD), viscose (CV), and lyocell (CLY) single jersey fabrics, while resistance to air permeability was increased with the increased nanofiber coating. High level of air resistance was achieved with 30 min of coating. In terms of comfort properties, the nanofiber coating proved to be advantageous due to its lower air permeability with its water vapor permeable structure. However, thermal insulation level of these fabrics was still low and fragile nanofiber layer needed to be protected. Therefore, a multi-layered fabric form was derived from combination of cotton and lyocell fabrics with a nanofiber layer. The results showed that nanofibers could be used to improve the wind-resistance and comfort properties of multi-layered knitted structures.