The prevention and removal of biofilm formation of Staphylococcus aureus strains isolated from raw milk samples by citric acid treatments

In this study, the antibiofilm activity of citric acid treatment on Staphylococcus aureus strains isolated from raw milk samples was evaluated. For this purpose, the prevention and removal of biofilm formation of S. aureus strains by citric acid treatments (2% and 10%) for 20 min were investigated for comparison with peracetic acid treatment (0.3%) on both microtitration plate and stainless steel coupons. The results indicated that the prevention and removal of biofilm formation and the numbers of prevented or removed S. aureus strains using citric acid treatments were observed to be higher than those using peracetic acid treatment on both surfaces. The prevention and removal of biofilm formation were substantially higher when the concentration of citric acid treatment increased from 2% to 10% and the stainless coupons were used. The results show that citric acid can be used as an alternative disinfectant in controlling biofilm formation in the dairy industry.     

UV-Light Absorption Properties of Cr-Doped Polyethyleneglycol (PEG)/γ-Glycidoxypropyltrimethoxysilane (GPTMS)/Chelated-Titanium Coating Materials Prepared by the Sol–Gel Process

New hybrid inorganic–organic glass coating materials, which contain polyethyleneglycol/γ-glycidoxypropyltrimethoxysilane/titanium(IV)-n-propoxide(2-methoxyethylacetoacetate)/chromium(III)nitrate [PEG/GPTMS/Ti(OR)(2-MEAA)/Cr³⁺] have been developed for UV-light absorption by using the sol–gel process. The effect of agitation time and temperature on UV-light absorption was investigated. The titanium complex was characterized by ¹H-NMR and FTIR spectroscopies. UV–Vis spectroscopy was used to investigate the optical properties of the coating materials. The results show that the coated glass has very low transmission in the UV region (300–400 nm) compared to the uncoated glass, especially at 150, 200, 250 and 300°C treatment temperatures after 1- and 18-hour agitation times. The UV-light transmission of the coated glass was not different from the uncoated glass between 80–100°C and 350–500°C.     

Robust semi-automatic head pose labeling for real-world face video sequences

Automatic head pose estimation from real-world video sequences is of great interest to the computer vision community since pose provides prior knowledge for tasks, such as face detection and classification. However, developing pose estimation algorithms requires large, labeled real-world video databases on which computer vision systems can be trained and tested. Manual labeling of each frame is tedious, time consuming, and often difficult due to the high uncertainty in head pose angle estimate, particularly in unconstrained environments that include arbitrary facial expression, occlusion, illumination etc. To overcome these difficulties, a semi-automatic framework is proposed for labeling temporal head pose in real-world video sequences. The proposed multi-stage labeling framework first detects a subset of frames with distinct head poses over a video sequence, which is then manually labeled by the expert to obtain the ground truth for those frames. The proposed framework provides a continuous head pose label and corresponding confidence value over the pose angles. Next, the interpolation scheme over a video sequence estimates i) labels for the frames without manual labels and ii) corresponding confidence values for interpolated labels. This confidence value permits an automatic head pose estimation framework to determine the subset of frames to be used for further processing, depending on the labeling accuracy required. The experiments performed on an in-house, labeled, large, real-world face video database (which will be made publicly available) show that the proposed framework achieves 96.98 % labeling accuracy when manual labeling is only performed on 30 % of the video frames.     

Intercalated polyaniline/Na-montmorillonite nanocomposites via oxidative polymerization

This work focuses on the preparation, characterization and electrical conductive properties of intercalated polyaniline/Na-montmorillonite nanocomposites. These materials consisting of polyaniline and Na-montmorillonite were prepared by oxidative polymerization with benzoyl peroxide as oxidizing agent. The synthesized nanocomposites were investigated by a series of characterization techniques; including Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermal analysis. X-ray diffraction and scanning electron microscopy images showed that the polyaniline was inserted into the clay layers. The modest increase in layer spacing was as much as 0.53 nm. The thermogravimetric analysis and differential thermal analysis demonstrated the improved thermal stability of the intercalated nanocomposites relative to the pure polyaniline due to the incorporated Na-montmorillonite. The room temperature electrical conductivity of nanocomposites varied from 1.0 × 10⁻⁷ to 5.8 × 10⁻⁵ Scm⁻¹.     

Comparison of restorative materials and surface alterations after prebiotic and probiotic beverages: A nanoindentation and SEM study

The purpose was to investigate the surface characteristics of various resin-based materials by immersing in probiotic beverages. A total of 420 disc-shaped samples (5 mm × 2 mm) were prepared from resin-based composites. Samples were divided into four groups and immersed for 10 min/day for 1 month in either a probiotic sachet, kefir, kombucha, or artificial saliva (control). Surface roughness was measured at baseline and 1 month. One sample of each of the tested materials was examined under nanoindentation to evaluate the reduced elasticity modulus and nanohardness scores. Scanning electron microscopy (SEM) was used to compare surface differences. Data were analyzed statistically using one-way ANOVA test and the significance was set at p < .05. The lowest roughness scores were observed in Z250, Estelite Bulk Fill, and HRi ENA in most of the test groups. Among conventional composites, Z250 group had the highest nanohardness and elasticity modulus scores. Among bulk-fill composites, Estelite Bulk Fill Flow had the lowest surface roughness after immersion in probiotic beverages and the highest nanohardness values. Reveal HD, as a bulk-fill group showed higher surface roughness and considerably lower nanohardness and elasticity modulus scores. Maximum height levels of samples were recorded. SEM images revealed voids and microcracks on the surfaces of test materials. Dentists may prefer Z250 as microhybrid and Estelite Bulk Fill Flow as bulk-fill composites for the restorations of patients who consume gut-friendly drinks regularly. When there are various types of materials, nanoindentation is a useful method for evaluating surface alterations and sensible comparisons.     

Anthocyanin and organic acid profiles of pomegranate (Punica granatum L.) juices from registered varieties in Turkey

This is the first study to analyse the profiles of anthocyanin (ACN) and organic acid (OA) and some physico‐chemical properties of pomegranate juices (PJs) obtained from nine registered varieties in Turkey. HPLC analyses revealed that there were significant differences between ACN contents (28–447 mg L^?1) and profiles (P < 0.01). The PJs contain maximum six ACNs, 3‐glucosides and 3,5‐diglucoside of delphinidin, cyanidin and pelargonidin. The major OA in PJs was citric acid (66–74%), followed by malic (6–12%), succinic (5–19%), nonidentified (0–14%) and tartaric acids (0.1–3.7%). Amongst individual OAs, citric acid had the most significant effects on TA (r = 0.9761), pH (r = 0.9208) values and sourness of PJs. As different from literature, results of this study revealed that malic acid contents of authentic PJs could be higher than 1.5 g L^?1. Consequently, ACN and OA profiles could be successfully used in quality control because all PJs have their own typical ACN and OA profiles.     

Biodesulfurization of Cayirhan Lignites

In this study, the lignite was improved oxidizing sulfur compounds by Thiobacillus thiooxidans and Thiobacillus ferrooxidans bacteria. Experiments in the batch reactors have been carried out 20% aqueous suspension of coal samples. Sugar beet molasses was used as the bacterial substrate. The maximum removal of combustible sulfur was obtained as 78.2% under the following conditions; addition 5% of T. thiooxidans and 5% T. ferrooxidans into coal suspension, 0.2 g molasses/g coal change, pH value of 3, at shaking rate of 70 rpm and at 40°C for 5 days.     

Effect of surface conditioning methods on the microtensile bond strength of repair composite to indirect restorative materials

This study evaluated the effect of surface conditioning methods on the microtensile bond strength (µTBS) of a restorative composite to indirect restorative materials. Blocks (5?×?5 × 4?mm³) (N?=?72) of (a) Zirconia (In-Ceram Zirconia, Vita) (ZR), (b) lithium disilicate glass ceramic (IPS Empress II, Ivoclar Vivadent) (LD), (c) Indirect resin composite (Gradia, GC) (GR) were fabricated (n?=?24 per group) and divided randomly into three groups: 1-Control: no conditioning, 2-Silane coupling agent, 3-Hydrofluoric acid (9.5%) (HF)+silane. Each block was duplicated in resin composite. The adhesion surfaces were conditioned with airborne-particle abrasion (110?µm Al₂O₃ particles). Half of the conditioned blocks received no bonding and the other half one coat of bonding (ED Primer II, Kuraray). Each conditioned block was bonded to a composite block with a resin luting agent (Panavia F2.0, Kuraray). The blocks were sectioned into 1?mm² microsticks and tested for microtensile bond strength (µTBS) (0.5?mm/min) in a μTBS testing machine. Failure types were evaluated under stereomicroscope and Scanning Electron Microscope (SEM). Data were analyzed using three-way ANOVA, Bonferroni corrected and independent sample t-tests (p?<?0.05). Significant effect of the bonding (p?<?0.001) and surface conditioning (p?<?0.001) were observed in all groups. The highest mean bond strength values were obtained in the bonded, HF etched and silanized groups of ZR, LD and GR (12.4?±?2.9, 28.1?±?1.5 and 27.2?±?2?MPa, respectively). HF acid?+?silane increased the repair bond values in all materials. Majority of the failure types were adhesive for ZR group, whereas HF?+?silane conditioned LD and GR groups presented predominantly cohesive failures in the cement.     

Heparin-coated poly(hydroxyethyl methacrylate/albumin) hydrogel networks: In vitro hemocompatibility evaluation for vascular biomaterials

Human serum albumin (AL) containing poly(hydroxyethyl methacrylate) (pHEMA; in tube form with an inner diameter of 6 mm) was synthesized for blood-contacting hydrogel networks via UV-initiated photopolymerization at 25°C. Tensile and breaking tests of pHEMA and pHEMA–AL-1–4 hydrogel networks were studied at their equilibrium water content. The mechanical strength of the hydrogel networks was found to be lowered by an increase in the ratio of AL in the polymer networks. To increase the blood compatibility and prevent thrombus formation, the surface of the pHEMA and pHEMA–AL-3 hydrogel compositions were coated with heparin (HEP). Contact-angle studies showed that the polarities (%) of the pHEMA–AL-3 and pHEMA–AL-3–HEP hydrogel networks were significantly increased in comparison with that of pure pHEMA. The fibrinogen adsorption and platelet adhesion were also reduced after the incorporation of AL and HEP into/onto hydrogel networks in comparison with the pure pHEMA control. Blood compatibility tests of the prepared hydrogel networks, which were intended to be used as blood-contacting materials, were examined with various parameters, such as the hemolytic activity, prothrombin time, activated thromboplastin time, and loss of blood cells in blood. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Improvement of bitumen performance with epoxy resin

This paper studies the modification of petroleum bitumen with epoxy resin. Different amounts of epoxy were doped into bitumen with 50/70 penetration grade and variations in viscosity as a function of temperature and additive concentration were determined. The effects of the epoxy additive were examined by rheometer, penetration, softening point, DSR (dynamic shear rheometer), DSC (differential scanning calorimeter), RTFOT (rolling thin film oven test), PAV (pressure aging vessel), BBR (bending beam rheometer) and surface tension tests. Adhesion and stability of bitumen aggregate mixtures prepared using original and modified bitumen were compared using Nicholson stripping and Marshall tests. The optimum dosage of the additive yielding the best rheological and performance properties was found to be 2% (w/w). Appreciable decrease in the formation of rutting, bleeding, stripping and cracking of modified bitumen may be obtained through epoxy addition.