Assessment of in vitro antitumoral and antimicrobial activities of marine algae harvested from the eastern Mediterranean sea

Antitumoral activities of five algal extracts obtained from the marine algae Scytosiphon lomentaria, Padina pavonica, Cystoseira mediterranea (Phaeophyceae), Hypnea musciformis and Spyridia filamentosa (Rhodophyta) were assessed against the human breast adenocarcinoma cell line MCF–7 and the human prostate carcinoma epithelium like cell lines DU 145, LNCaP, PC3 using the cytotoxic assay, in vitro. The crude extract of S. filamentosa showed strong cytotoxic activity against the DU-145 cell line, and it showed less than 10% cell viability after treatment. Antimicrobial activities of the crude extracts of algae (with the exception of H. musciformis) were also tested by disc diffusion assay against three Gram positive and five Gram negative bacterial strains and against the yeast pathogen Candida albicans. Among the extraxts, S. lomentaria extract (prepared with methanol) inhibited highly Gram negative bacterium Salmonella typhimurium growth while C. albicans growth was only inhibited by C.mediterrranea extract

The effects of Environmental Enrichment on Some Physiological and Behavioral Parameters of Broiler Chicks

WOS: 000406295200024This study aims to examine the effects of environmental enrichment (EE) practices on some physiological and behavioral parameters of broiler chicks. A total of 280 one-day old Ross 308 mixed-sex broiler chicks with an average initial body weight of 44.5 +/- 0.37 g were used in a 42-d trial. Broiler chicks were randomly allocated to 20 pens composed of 14 birds in 1x1.4m sized floor area. Each of the EE treatment consisted of 5 replicate pens (70 chickens per treatment). The treatments were 1) control; 2) perch for EE; 3) ball for EE; 4) mirror for EE; and 5) dust for EE. Final body weights, tonic immobility test results, and rectal temperatures were recorded. Spleen, liver, and bursa fabricius weights were measured. The blood biochemistry of birds was analyzed at the end of the experiment. Besides, gait score test was applied on the 42(nd) day of experiment. Body weight gain, lymphoid organ weights and rectal temperature values of broilers were not affected by EE treatments on the 21(st) and 42(nd) days of the study. At the end of the study, WBC values, tonic immobility values and gait scores of the control groups were found higher than those of the EE groups. HCT and PLT values of the ball groups were found lower than the other groups, concluding that EE improved the welfare of birds.Scientific Research Projects Coordinatorship of Ahi Evran University in Turkey [PYO-ZRT.4003/2.13.007]This work, a part of MSc study of Mehmet Yildirim, was supported by the Scientific Research Projects Coordinatorship of Ahi Evran University in Turkey with PYO-ZRT.4003/2.13.007 project number

Additional Evidence for the Surface Origin of the Peculiar Angular-Dependent Magnetoresistance Oscillations Discovered in a Topological Insulator Bi_{1-x}Sb_{x}

We present detailed data on the unusual angular-dependent magnetoresistance oscillation phenomenon recently discovered in a topological insulator Bi_{0.91}Sb_{0.09}. Direct comparison of the data taken before and after etching the sample surface gives compelling evidence that this phenomenon is essentially originating from a surface state. The symmetry of the oscillations suggests that it probably comes from the (111) plane, and obviously a new mechanism, such as a coupling between the surface and the bulk states, is responsible for this intriguing phenomenon in topological insulators.Comment: 5 pages, 4 figures, Proceedings manuscript for the 19th International Conference on the Application of High Magnetic Fields in Semiconductor Physics and Nanotechnology (HMF-19

FMR Study of Co/Ti Bilayer Thin Films

. We focused on the interaction between two ferromagnetic cobalt layers through a non-magnetic titanium layer. The magnetic properties of the structure were characterized by ferromagnetic resonance technique (FMR). The data were collected as a function of non-magnetic titanium layer thickness. Co/Ti multilayer (Ti (50 {\AA})/Co(45 {\AA})/Ti(2-40 {\AA})/Co(40 {\AA})/Ti(100 {\AA}))films were grown onto naturally oxidized p-type single crystal Si (100) substrate at UHV condition with magnetron sputtering system at room temperature. The thickness of Ti spacer layer ranges from 2 to 40 {\AA} with 2 {\AA} steps. We did not observe usual optic and acoustic modes; instead we had two broad overlapped peaks for the films ranged from 6 {\AA} to 40 {\AA}. One interesting result was the high anisotropic resonance field values for these films. Exchange coupling between ferromagnetic layers causes shift on resonance field values but these shifts in our samples were much larger than expected. This large anisotropic behavior is not clear at the moment. Our theoretical model was not able to determine a value for the exchange coupling parameter. One reason can be the close thickness values for Co sublayers. The other reason can be the Ti non-magnetic layer. If titanium did not grow layer by layer on cobalt, the cobalt ferromagnetic layers may behave as a single layer. As a result one cannot observe exchange interaction between ferromagnetic layers through non-magnetic spacer.Comment: 6 pages, 5 figure

Oscillatory angular dependence of the magnetoresistance in a topological insulator Bi_{1-x}Sb_{x}

The angular-dependent magnetoresistance and the Shubnikov-de Haas oscillations are studied in a topological insulator Bi_{0.91}Sb_{0.09}, where the two-dimensional (2D) surface states coexist with a three-dimensional (3D) bulk Fermi surface (FS). Two distinct types of oscillatory phenomena are discovered in the angular-dependence: The one observed at lower fields is shown to originate from the surface state, which resides on the (2\bar{1}\bar{1}) plane, giving a new way to distinguish the 2D surface state from the 3D FS. The other one, which becomes prominent at higher fields, probably comes from the (111) plane and is obviously of unknown origin, pointing to new physics in transport properties of topological insulators.Comment: 4 pages, 5 figures, revised version with improved data and analysi

Angular-dependent oscillations of the magnetoresistance in Bi_2Se_3 due to the three-dimensional bulk Fermi surface

We observed pronounced angular-dependent magnetoresistance (MR) oscillations in a high-quality Bi2Se3 single crystal with the carrier density of 5x10^18 cm^-3, which is a topological insulator with residual bulk carriers. We show that the observed angular-dependent oscillations can be well simulated by using the parameters obtained from the Shubnikov-de Haas oscillations, which clarifies that the oscillations are solely due to the bulk Fermi surface. By completely elucidating the bulk oscillations, this result paves the way for distinguishing the two-dimensional surface state in angular-dependent MR studies in Bi2Se3 with much lower carrier density. Besides, the present result provides a compelling demonstration of how the Landau quantization of an anisotropic three-dimensional Fermi surface can give rise to pronounced angular-dependent MR oscillations.Comment: 5 pages, 5 figure

Room-temperature ferromagnetism in Sr_(1-x)Y_xCoO_(3-delta) (0.2 < x < 0.25)

We have measured magnetic susceptibility and resistivity of Sr$_{1-x}$Y$_x$CoO$_{3-\delta}$ ($x=$ 0.1, 0.15, 0.2, 0.215, 0.225, 0.25, 0.3, and 0.4), and have found that Sr$_{1-x}$Y$_x$CoO$_{3-\delta}$ is a room temperature ferromagnet with a Curie temperature of 335 K in a narrow compositional range of 0.2 $\leq x\leq$ 0.25. This is the highest transition temperature among perovskite Co oxides. The saturation magnetization for $x=$ 0.225 is 0.25 $\mu_B$/Co at 10 K, which implies that the observed ferromagnetism is a bulk effect. We attribute this ferromagnetism to a peculiar Sr/Y ordering.Comment: 5 pages, 4 figure

Revealing puddles of electrons and holes in compensated topological insulators

Three-dimensional topological insulators harbour metallic surface states with exotic properties. In transport or optics, these properties are typically masked by defect-induced bulk carriers. Compensation of donors and acceptors reduces the carrier density, but the bulk resistivity remains disappointingly small. We show that measurements of the optical conductivity in BiSbTeSe$_2$ pinpoint the presence of electron-hole puddles in the bulk at low temperatures, which is essential for understanding DC bulk transport. The puddles arise from large fluctuations of the Coulomb potential of donors and acceptors, even in the case of full compensation. Surprisingly, the number of carriers appearing within puddles drops rapidly with increasing temperature and almost vanishes around 40 K. Monte Carlo simulations show that a highly non-linear screening effect arising from thermally activated carriers destroys the puddles at a temperature scale set by the Coulomb interaction between neighbouring dopants, explaining the experimental observation semi-quantitatively. This mechanism remains valid if donors and acceptors do not compensate perfectly.Comment: 11 pages with 7 figures plus supplemental material (3 pages

Structure and Magnetism of HoBaCo2O5+delta Layered Cobaltites with 0.02<delta<0.22

In this paper we have studied, by means of high-resolution neutron powder diffraction and magnetic susceptibility, the structural and magnetic features of selected samples of the HoBaCo2O5+delta layered cobaltite in the low oxygen content range (0.02<delta<0.22). The results shows a strong antiferromagnetic contribution at room temperature coupled to an intermediate spin state of the Co3+ ions.Comment: 16 pages, 4 figures, submitted to Solid State Com