Defect assisted optical limiting performance of hexagonal boron nitride nanosheets in aqueous suspension and PMMA nanocomposite films

Defect-assisted nonlinear absorption (NLA) and optical limiting (OL) performance of hexagonal boron nitride nanosheets (h-BNNS) in aqueous suspension and in polymethyl methacrylate matrix (PMMA) as nanocomposite films were studied using open-aperture Z-scan method. To evaluate the transmission in open-aperture Z-scan data, a theoretical model accounting one photon absorption (OPA), two photon absorption (TPA), free carrier absorption (FCA) and saturation of each process was considered. Defect-assisted NLA coefficients and saturation intensity thresholds were extracted from the fitting of the experimental results for 532 and 1064 nm pulse wavelengths. Strong defect-assisted NLA response of h-BNNS was observed while NLA at 532 nm was considerably stronger. This is attributed to the excitation of a greater number of defect states over a wider energy range. Our findings showed that h-BNNS/PMMA nanocomposite films feature highly required properties in OL applications and can function in OL applications in a wide spectral range (-200-1064 nm)

Ultrafast electron/energy transfer and intersystem crossing mechanisms in bodipy-porphyrin compounds

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin

Microbiological Quality of Raw Meat Balls: Produced and Sold in the Eastern of Turkey

International audience(Cass. com., 27 sept. 2005, pourvoi n° 03-20.136, Sté Fériac et Sté Interaméricana c/ Crédit agricole

Occurence and antimicrobial resistance of Arcobacter species in food and slaughterhouse samples

Abstract The objectives of this study were i) to isolate Arcobacter species (Arcobacter butzleri, Arcobacter skirrowii, Arcobacter cryaerophilus) from different foods and sources, ii) to verify the isolates by multiplex PCR assay, iii) to detect the antibiotic resistance profiles of the isolates. In this study a total of 60 Arcobacter isolates were obtained. Arcobacter species were mostly isolated from swab samples (40%), followed by wastewater (29.1%), broiler wing meat (30%), raw milk (23.9%) and minced meat (6.6%). Regarding the seasonal distribution of Arcobacter from swab and wastewater samples, the bacterium was commonly isolated from wastewater in winter and spring, while it was frequently detected in swab samples during autumn and spring. All of the isolates were found to be resistant to nalidixic acid, ampicillin, rifampin, and erythromycin. The most effective antibiotic was tetracycline, because 96.66% of the isolates were susceptible against it. This is the first report of the isolation, seasonal distribution and antimicrobial susceptibility of Arcobacter species in cattle slaughterhouse samples in Turkey. These results indicate that foods of animal origin and cattle slaughterhouses are significant source of the antimicrobial resistant arcobacters

Occurence and antimicrobial resistance of Arcobacter species in food and slaughterhouse samples

Abstract The objectives of this study were i) to isolate Arcobacter species (Arcobacter butzleri, Arcobacter skirrowii, Arcobacter cryaerophilus) from different foods and sources, ii) to verify the isolates by multiplex PCR assay, iii) to detect the antibiotic resistance profiles of the isolates. In this study a total of 60 Arcobacter isolates were obtained. Arcobacter species were mostly isolated from swab samples (40%), followed by wastewater (29.1%), broiler wing meat (30%), raw milk (23.9%) and minced meat (6.6%). Regarding the seasonal distribution of Arcobacter from swab and wastewater samples, the bacterium was commonly isolated from wastewater in winter and spring, while it was frequently detected in swab samples during autumn and spring. All of the isolates were found to be resistant to nalidixic acid, ampicillin, rifampin, and erythromycin. The most effective antibiotic was tetracycline, because 96.66% of the isolates were susceptible against it. This is the first report of the isolation, seasonal distribution and antimicrobial susceptibility of Arcobacter species in cattle slaughterhouse samples in Turkey. These results indicate that foods of animal origin and cattle slaughterhouses are significant source of the antimicrobial resistant arcobacters

Carcass and Meat Quality Characteristics of White and Multicolor Geese under Local Breeder Conditions

The purpose of this study was to define the meat quality characteristics of White and Multicolor geese under local breeder conditions. While carcass and edible offal percentages were similar breast, back and wing ratios were statistically different between White and Multicolor geese. Phenotypic color differentiation between geese varieties was reflected on both breast meat and skin (except a* value). While White geese had better values than Multicolor geese for saturated fatty acid and monounsaturated fatty acid, Multicolor geese were higher than White geese for polyunsaturated fatty acid. Nutritive value of White variety was higher than Multicolor variety in breast meat, skin and abdominal fat

Aflatoxin M1 Levels in Milk Powder Consumed in Turkey

WOS: 000262560800025Aflatoxins are secondary metabolites produced by certain strains of Aspergillus species. They have immunsupresive, genotoxic, hepatoxic and carcinogenic (particularl liver cancer) effects which are the common problems worldwide for people of all age groups. This study was aimed to investigate the presence and levels of AFM1 in the milk powder sold in retail stores of Kars, Erzurum, Mersin, Konya and Ankara vicinities in Turkey. AFM1 was determined in 62.5% of all samples analyzed. Amount of the AFM1 in samples was higher in 45% of the samples than the maximum allowed level according to the Turkish Food Codex (TFC) criteria (500 ng kg(-1)). Consequently, milk powders sold in retail stores in Turkey pose a great risk for public health. Serious programmes controlling the occurence of the aflatoxin will surely help on dealing with the risk factors

Prevalence of Listeria monocytogenes in poultry meat

AbstractThe objectives of this study were i) to isolate Listeria spp. and Listeria monocytogenes in broiler wing meat samples, ii) to confirm the isolates by PCR, based on prs and hly A gene sequences, iii) to determine the seasonal and monthly distribution of the isolates. A total of 120 broiler wing meat samples (60 packaged pieces wrapped using strech film in styrofoam plates and 60 unpackaged pieces) bought from different markets in Hatay province were analysed. Listeria spp. was isolated from 57 (47.5%) out of 120 samples. Fifty-four, out of 57 Listeria spp. isolates were identified as L. monocytogenes. L. monocytogenes was isolated from the samples collected during the spring, winter, summer, and autumn at the levels of 26.6%, 40%, 53.3%, 60%, respectively. In this study, the isolation rates were found to be the highest in autumn, while the isolation rates were found to be the lowest in spring. As a consequence, high prevalence of Listeria spp. and L. monocytogenes in poultry wing meat samples may pose a risk for human health. We consider that with obeying the rules of good hygiene practices (GHP), good manufacturing practices (GMP) and HACCP can minimize the contamination with Listeria spp

Occurrence of Zeranol in Ground Beef Produced in Kars, Turkey

WOS: 000262560800022Anabolic agents are used to increase live body weight in food animals. Zeranol is such an agent applied to cattle as subcutaneous implants in some countries. There is the potential risks that zeranol could affect hormonal and mineral metabolisms and have carcinogenic and teratogenic effects. Due to potential risks on animal and public health, use of zeranol as an anabolic agent was banned in Europian Union and in Turkey. In this study, it was aimed to investigate the presence of zeranol in ground beef samples marketed in Kars city which is one of the important ports in food animal production in Turkey. Seventy ground beef samples were collected from the retail shops to monitor occurrence of zeranol. The quantitative analysis of zeranol in beef samples were carried out by Competitive Enzyme Immune Assay (ELISA) test procedure as described by R-Biofarm GmBH, Germany ((Ridascreen (R) Zeranol, Tissue Samples, muscle, liver, kidney etc. Art. No: R3301). Of the 70 ground beef samples analyzed, 66 samples (94.28%) bad level of zeranol under the detection limit (62 ppt), while 4 samples out of 70 (5.72%) contained zeranol ranging from 100-110 ppt