The prevalence of Escherichia coli O157 and O157:H7 in ground beef and raw meatball by immunomagnetic separation and the detection of virulence genes using multiplex PCR

The present study was conducted to investigate the presence of Escherichia coli O157 and O157:H7 strains and to detect the presence of the stx1, stx2, and eaeA genes in isolates derived from 200 samples (100 samples from fresh ground beef and 100 samples from raw meatball). The samples were purchased from the Samsun Province in Turkey, over a period of 1 year. Enrichment-based immunomagnetic separation and multiplex polymerase chain reaction were applied for these analyses. E. coli O157 was detected in five of the 200 (2.5%) samples tested (one isolated from ground beef and four from meatball samples), whereas E. coli O157: H7 was not detected in any sample. During the analysis, eight strains of E. coli O157 were obtained. The genes stx1, stx2, and eaeA were detected in two E. coli O157 isolates obtained from two meatball samples, whereas only the eaeA and the stx2 genes were detected in four E. coli O157 strains that were isolated from one meatball sample. None of the stx1, stx2, and eaeA was detected in the E. coli O157 isolates obtained from the ground beef and the one meatball samples.     

Co-liquefaction of Yatağan lignite and waste tire under catalytic conditions. Part 1. Effect of fresh tetraline and recycled tetraline on the conversion

In this study, the effect of solvent type and the solvent/solid ratio on the liquefaction of Mu?la-Yatagan lignite (YL) combined with waste tire (WT) under catalytic conditions investigated. Liquefaction experiments carried out the following conditions, a reaction temperature of 400°C, a catalyst concentration of 3%, solvent/solid ratio from 1/1 to 9/1, reaction time of 90 min, lignite/waste ratio of 1/1. In addition, mixing speed was 400 rpm, and the nitrogen gas pressure fixed at 30 bar. After the each of liquefaction experiments finished, the soluble products (SP) classified as preasphaltene (PAS), asphaltene (AS) and oil+gas (OG), by solvent extraction. Due to the optimum total conversion determined, fresh tetraline obtained as the most favorable solvent with 71.71%, for the liquefaction of YL with WT. However, the total conversion for recycling tetraline is 68.6%. According to the results, co-liquefaction of YL combined with WT using recycle solvent is the one way to offer, alternatively of using crude oil, producing SP for not crude oil, producing SP for not only fuel-oil production but also prefer chemical raw materials. With respect to the optimum oil+gas yield results, the most convenient solvent type and the solvent/solid ratio are the recycled solvent and its 3/1 ratio.     

Monocular deprivation alters the direction of functional and morphological asymmetries in the pigeon's (Columba livia) visual system.

One-day-old pigeons (Columba livia) were monocularly deprived by occluding the left or the right eye for 10 days. Up to 3 years later, degree and direction of functional and morphological asymmetries of deprived and control pigeons were analyzed. In control pigeons, the usual right-eye superiority was obtained in a visual discrimination task. In left-eye deprived pigeons, this behavioral asymmetry was strengthened, whereas the direction of lateralization was reversed in right-eye deprived birds. A morphological tectum analysis revealed that control and left-eye deprived pigeons displayed similar asymmetries, with the left-monocular deprived pigeons exhibiting more pronounced left-right differences. Tectal morphometry of right-eye deprived pigeons displayed a reversed pattern. Overall, the present study shows that a short period of posthatch monocular deprivation is sufficient to alter behavioral and morphological visual asymmetry for several years. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis of Cherry Stalk Extract Based Organic@Inorganic Hybrid Nanoflowers as a Novel Fenton Reagent: Evaluation of Their Antioxidant,Catalytic, and Antimicrobial Activities

First time in this study, organic@inorganic hybrid copper nanoflowers (Cu NFs) were synthesized by using cherry stem extract as an organic component and Cu²⁺ ion as an inorganic component. For this purpose, cherry stalk extracts were obtained by using ethanol and water solvents. Cu NFs were synthesized in different amounts of extract (100–1000 µl) and under various pH (7.4–9) conditions. The morphologies of the synthesized Cu NFs were evaluated by field emission scanning electron microscope (FE-SEM). The functional groups in the cherry stem extract, which play an active role for the synthesis process, and the crystal structure of NFs were investigated by Fourier transform ?nfrared spectroscopy and X-ray diffraction techniques, respectively. It has been determined by the FE-SEM analysis that ethanol and water based cherry stem extracts are suitable for Cu NFs synthesis in a wide range of pH (7.4–9). This data is crucial for overcoming important limitations for NF synthesis, such as narrow-range medium pH. The catalytic, antioxidant, and antimicrobial activities of Cu NFs were evaluated. It was revealed that Cu NFs have catalytic, antioxidant, and antimicrobial activities. It is recommended that, cherry stem extract and different inorganic components are functional to synthesize numerous NFs and to evaluate the adequacy of use in biomedical fields.

     

A SWOT-AHP analysis on biodiesel as an alternative future marine fuel

Clean Technologies and Environmental Policy - Alternative fuels especially those produced in a green way are essential for meeting supplying the world's growing energy needs. Biodiesel is...     

Hertzian crack propagation in graded glass/ceramic composites

In literature, the concept of material gradation is shown to inhibit surface crack initiation in glass/ceramic composites subjected to Hertzian indentation. However, surface cracks could yet initiate due to relatively higher loadings or in the presence of surface flaws/defects. Hence, characterization of graded composites concerning the resistance against Hertzian crack initiation and propagation manifests itself as a prominent matter. In this study, axisymmetric Hertzian cracks evolving in graded glass/ceramic composites propelled by a rigid cylindrical punch are investigated employing a novel recursive method, called the stacked-node propagation procedure. Crack trajectories and their propagation susceptibilities are predicted via the minimum strain energy density (MSED) criterion regarding the crack growth resistance (R-curve) of ceramics. The stress trajectory approach is also considered for a homogeneous glass to reveal the reliance and effectiveness of the MSED criterion in the present crack problems. The Mori–Tanaka relations are adopted to model the elastic modulus and Poisson's ratio variations through the composites, which are implemented on the simulations via the homogeneous finite element approach. Hertzian crack problem of a practically producible graded composite comprised of oxynitride glass and a fine-grained silicon nitride ceramics (Si₃N₄) is treated as a case study. The degree of material gradation is assessed for the mitigation of surface crack initiation and propagation risks.     

The Use of Digital Image Processing Method to Estimate the Foam Characteristics of Polyurethane

Four air-bubbled polyurethane (PU) foams with different polyol:PMDI wt.% are produced, respectively. The chemical reaction mechanisms of polyurethane and bubble formation are proposed by performing standard Gibbs free energy calculations using the DFT M06-2X/6-31+G(d,p) method. The local minima, transition states, and intermediates in reaction mechanisms are detected. It is concluded that both reactions are exothermic. Then, raw images of the produced PU foams are taken with a 13 MP mobile phone camera, which can be considered inexpensive, and the mean radii of the pores are calculated by an image processing based method (IPBM) on a standard desktop computer with an i5 processor. It is determined that there is a close relationship between the calculated mean radius and instrumentally measured thermal conductivity coefficient of the foams. However, the thermal conductivity coefficients are independent of the calculated number and percentage of the pores. The mean radii of the samples calculated by the proposed IPBM are close to that of the SEM, with acceptable relative errors of less than 10%. Finally, it is concluded that IPBM, which is a more cost-effective, cleaner, and faster method than SEM, might replace SEM in the air bubble analysis of PU foams.     

Stability analysis and controller design for consensus in discrete-time networks with heterogeneous agent dynamics

In this paper, we study the heterogeneous consensus problem in directed networks consisting of first- and second-order agents that can only receive the position states of their neighbors. Necessary and sufficient conditions on the controller parameters are obtained in order to achieve consensus in the network. The mathematical expressions of the consensus equilibria are given for two different scenarios. Furthermore, we propose a systematic method for choosing controller parameters to ensure stability in a network of agents with heterogeneous dynamics. Several numerical examples are also provided to illustrate the theoretical results.