Damping by slow relaxing rare earth impurities in Ni80Fe20

Doping NiFe by heavy rare earth atoms alters the magnetic relaxation properties of this material drastically. We show that this effect can be well explained by the slow relaxing impurity mechanism. This process is a consequence of the anisotropy of the on site exchange interaction between the 4f magnetic moments and the conduction band. As expected from this model the magnitude of the damping effect scales with the anisotropy of the exchange interaction and increases by an order of magnitude at low temperatures. In addition our measurements allow us to determine the relaxation time of the 4f electrons as a function of temperature

Composite Spin Waves, Quasi-Particles and Low Temperature resistivity in Double Exchange Systems

We make a quantum description of the electron low temperature properties of double exchange materials. In these systems there is a strong coupling between the core spin and the carriers spin. This large coupling makes the low energy spin waves to be a combination of ion and electron density spin waves. We study the form and dispersion of these composite spin wave excitations. We also analyze the spin up and down spectral functions of the temperature dependent quasi-particles of this system. Finally we obtain that the thermally activated composite spin waves renormalize the carriers effective mass and this gives rise to a low temperature resistivity scaling as T ^{5/2}.Comment: 4 pages, REVTE

Electron correlations in Co2_2Mn1−x_{1-x}Fex_xSi Heusler compounds

This study presents the effect of local electronic correlations on the Heusler compounds Co$_2$Mn$_{1-x}$Fe$_x$Si as a function of the concentration $x$. The analysis has been performed by means of first-principles band-structure calculations based on the local approximation to spin-density functional theory (LSDA). Correlation effects are treated in terms of the Dynamical Mean-Field Theory (DMFT) and the LSDA+U approach. The formalism is implemented within the Korringa-Kohn-Rostoker (KKR) Green's function method. In good agreement with the available experimental data the magnetic and spectroscopic properties of the compound are explained in terms of strong electronic correlations. In addition the correlation effects have been analysed separately with respect to their static or dynamical origin. To achieve a quantitative description of the electronic structure of Co$_2$Mn$_{1-x}$Fe$_x$Si both static and dynamic correlations must be treated on equal footing.Comment: 12 pages, 5 figure

Control of Aspergillus niger with garlic, onion and leek extracts

Antifungal activity of “Allium” vegetables that is garlic (Allium sativum L.), onion (Allium cepa L.) and leek (Allium porrum L.) were investigated against Aspergillus niger. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of aqueous, ethyl alcohol and acetone extracts were determined by disc diffusion and broth dilution methods in the test tubes. Onion extract with ethyl alcohol (275 mg/mL MFC), aqueous garlic extract (325 mg/mL MFC) and aqueous leek extract (900 mg/mL MFC) found the most inhibitory against A. niger

Reactivity of TNF-α, NF-κB, and TGF-β in Liver Tissue of Rats Due to the Sand Mussel Consumption

Toxic substances such as heavy metals have been reported to accumulate by aquatic organisms. In this study, it was aimed to investigate the histopathological changes that may occur in the liver parenchyma, the largest gland of the digestive system, by feeding the rats with sand mussel. The samples were analyzed for cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) by ICP-OES). The liver tissue samples were stained with Hematoxylin-Eosin (H&E), and immuohitochemically staining inflamatory marker TNF-α, NF-κB, and fibrotic factor TGF-β. Heavy metal accumulation in sand mussel tissue suggests that it may triggers the toxicity in tissues with the consumption frequently that the hepatotoxic effect was quite severe especially in rats fed with sand mussel. Also immunoreactivity of TNF-α, TGF-β and NF-κB were observed in the liver cells of especially second group. As a result, aquatic ecosystem can be affected with environmental pollution. It has been shown that marine based food obtained from polluted areas can trigger the hepatotoxicity

Impacts of the COVID-19 outbreak on food safety attitude, knowledge, and behavior

The potential impact of the virus on food safety during the COVID-19 outbreak has posed a critical challenge to governments, the food industry, and consumers worldwide. The aim of this study is to evaluate the knowledge, attitudes, and behaviors of adult people regarding food safety during the COVID-19 outbreak. It is a cross-sectional study which is based on internet survey data of 1049 residents from seven regions of Turkey. The survey includes questions about the level of knowledge and attitude toward food safety during the COVID-19 outbreak. It has been observed that over 90% of the participants have correct knowledge about what to do in food shopping during the COVID-19 process. 56.6% of the participants stated that COVID-19 can be transmitted through food or food packaging, 81.0% stated that food packages should be disinfected in order to be protected from COVID-19 and 37.7% stated that COVID-19 is more resistant than other bacteria or viruses. While the presence of gender (p = 0.748) and chronic disease (p = 0.181) does not affect the number of correct answers to questions about food safety during the COVID-19 process, education (p < 0.001) and age group (p < 0.001) do. Those who are in the COVID-19 risk group and those living with the individual(s) in the COVID-19 risk group (respectively; p = 0.036, p = 0.033). Turkish consumers had a high level of knowledge about food safety, positive attitudes, frequent hand hygiene, cleaning and sanitizing activities, and adherence to social seclusion standards when shopping or dining out

Control of Aspergillus niger with garlic, onion and leek extracts

Antifungal activity of "Allium" vegetables that is garlic (Allium sativum L.), onion (Allium cepa L.) and leek (Allium porrum L.) were investigated against Aspergillus niger. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of aqueous, ethyl alcohol and acetone extracts were determined by disc diffusion and broth dilution methods in the test tubes. Onion extract with ethyl alcohol (275 mg/mL MFC), aqueous garlic extract (325 mg/mL MFC) and aqueous leek extract (900 mg/mL MFC) found the most inhibitory against A. niger

Utjecaj praška Spiruline platensis na mikrofloru jogurta i acidofilnog mlijeka

The main purpose of this research was to monitor the influence of the powdered Cyanobacterium Spirulina platensis addition to plain yoghurt and the yoghurt containing Lactobacillus acidophilus on survival of the microbiota during the refrigerated storage. The cell viability of yoghurt starter cultures (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) and Lactobacillus acidophilus under refrigeration conditions in yoghurts prepared with (0.5 or 1.0 (w/w) %) and without the addition of Spirulina powder was investigated. The yoghurts were prepared under hygienic laboratory conditions and their pH and acidity were controlled during the process. The samples of yoghurts were stored at 4 °C and investigated on days 1, 5, 10, 15, 20, 25 and 30. Viable counts of the lactic acid bacteria were above 6 cfu g-1of all “spirulina powder” added samples whereas control yoghurt samples contained lower lactic acid bacteria count at the end of the storage period. Addition of 1 % Spirulina platensis powder into the yoghurts did not cause significant differences on the viable lactic acid bacteria (p≤0.05). The results showed the positive effect of S. platensis powder on the survival of the lactic acid bacteria during storage of yoghurt (P≤0.05). The sensory analysis was also performed for the yoghurt samples. Sensory scores of 0.5 % spirulina powder added yoghurt samples were better than 1 % spirulina powder added ones. It was determined that spirulina powder added yoghurt is a good medium of lactic acid bacteria during the 30 days of refrigerated storage.Glavni cilj ovog istraživanja bio je ispitivanje utjecaja dodatka praškastog Cyanobacterium Spirulina platensis u jogurt te jogurt obogaćen s Lactobacillus acidophilus na preživljavanje mikroorganizama tijekom čuvanja u hladnjaku. Ispitivano je preživljavanje starter kulture jogurta (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus) te Lactobacillus acidophilus u uzorcima pripremljenim uz dodatak 0,5 % ili 1 % (w/w) te bez dodatka spiruline, nakon čuvanja u hladnjaku. Uzorci su pripremljeni u higijenskim laboratorijskim uvjetima te je tijekom postupka kontrolirana njihova pH vrijednost i kiselost. Uzorci jogurta čuvani su na 4 °C te su ispitivanja izvršena nakon 1, 5, 10, 15, 20, 25 i 30 dana čuvanja u hladnjaku. Broj živih stanica bakterija mliječne kiseline bio je iznad 6 cfu/g za sve uzorke s dodanim praškom Spiruline platensis, dok su kontrolni uzorci jogurta sadržavali manje bakterija mliječne kiseline na kraju vremena skladištenja. Dodatak 1 % Spiruline platensis u uzorke jogurta nije dao značajne razlike u broju živih bakterija mliječne kiseline (p≤0,05). Rezultati pokazuju pozitivan učinak dodatka praška Spiruline platensis na preživljavanje bakterija mliječne kiseline tijekom razdoblja skladištenja jogurta. Provedena je i senzorska analiza pripremljenih uzoraka. Senzorske ocjene uzoraka pripremljenih uz dodatak 0,5 % Spiruline platensis bile su bolje od uzoraka uz dodatak od 1 %. Zaključeno je da su uzorci kojima je dodan prašak dobar medij za bakterije mliječne kiseline tijekom 30 dana hladnog skladištenja