Karyotype analysis of chub, Squalius cephalus (Linnaeus, 1758) (Teleostei: Cyprinidae) from Karasu River, Erzurum, Turkey

The karyotypic characteristics of chub, Squalius cephalus have been investigated by examining metaphase chromosomes spreads obtained from gill and kidney tissues. The fish used in the study were caught with fishing nets from Dumlu Stream, one of the main tributaries of the Karasu River. The live fish were transported to the laboratory, kept in a well aerated aquarium before analysis and then were injected intraperitoneally with doses of phytohemagglutinin, 0.01 ml.g-1 BW of 1% solution with 48-h interval to induce cell divisions. At the end of the period, the fish were injected intraperitoneally with doses of colchicine (0.01 ml.g-1 BW of 6% solution) and left for 3 hours before anesthesia and sacrificing. The best treatment parameters for preparing good metaphase chromosome spreads from the gill and kidney cells were performed as hypotonic (0.075 M KCl) treatment for 50 minutes, fixation with cold Carnoy solution at 3:1 ratio (methanol: acetic acid) and a concentration of 5% Giemsa for 35 minutes. The diploid chromosome number of this species was 2n = 50. The fundamental arm number (FN) was 92. The karyotypes were composed of 5 metacentric, 11 submetacentric, 5 subtelocentric and 4 acrocentric chromosome pairs (10 M + 22 SM + 10 ST + 8 A). No sex chromosomes were cytologically detected in this fish

All unitary cubic curvature gravities in D dimensions

We construct all the unitary cubic curvature gravity theories built on the contractions of the Riemann tensor in D -dimensional (anti)-de Sitter spacetimes. Our construction is based on finding the equivalent quadratic action for the general cubic curvature theory and imposing ghost and tachyon freedom, which greatly simplifies the highly complicated problem of finding the propagator of cubic curvature theories in constant curvature backgrounds. To carry out the procedure we have also classified all the unitary quadratic models. We use our general results to study the recently found cubic curvature theories using different techniques and the string generated cubic curvature gravity model. We also study the scattering in critical gravity and give its cubic curvature extensions.Comment: 24 pages, 1 figure, v2: A subsection on cubic curvature extensions of critical gravity is added, v3: The part regarding critical gravity is revised. Version to appear in Class. Quant. Gra

A Complete Classification of Higher Derivative Gravity in 3D and Criticality in 4D

We study the condition that the theory is unitary and stable in three-dimensional gravity with most general quadratic curvature, Lorentz-Chern-Simons and cosmological terms. We provide the complete classification of the unitary theories around flat Minkowski and (anti-)de Sitter spacetimes. The analysis is performed by examining the quadratic fluctuations around these classical vacua. We also discuss how to understand critical condition for four-dimensional theories at the Lagrangian level.Comment: 20 pages, v2: minor corrections, refs. added, v3: logic modified, v4: typos correcte

Noncritical Einstein-Weyl Gravity and the AdS/CFT Correspondence

We explore four-dimensional Einstein-Weyl gravity and supergravity on anti-de Sitter spacetime. For a specific range of the coupling with appropriate boundary conditions, we show the effective equivalence of the theory with Einstein gravity and AdS supergravity at the quadratic Lagrangian level. Furthermore we show that these equivalences can be promoted to the full nonlinear level. We also show that the similar behavior holds for the generalized Gibbons-Hawking terms. From this we find that the correlation functions in the dual conformal field theory of Einstein-Weyl gravity and supergravity can be readily read off from corresponding ones from Einstein gravity and AdS supergravity. We also give comments on some issues in critical gravity and supergravity as well as conformal gravity and supergravity.Comment: 20 pages, 1 figure: v2, references and footnote added, typos correcte

In Vivo Quantitative Study of Sized-Dependent Transport and Toxicity of Single Silver Nanoparticles Using Zebrafish Embryos

Nanomaterials possess distinctive physicochemical properties (e.g., small sizes and high surface area-to-volume ratios) and promise a wide variety of applications, ranging from the design of high quality consumer products to effective disease diagnosis and therapy. These properties can lead to toxic effects, potentially hindering advances in nanotechnology. In this study, we have synthesized and characterized purified and stable (nonaggregation) silver nanoparticles (Ag NPs, 41.6 ± 9.1 nm in average diameter) and utilized early developing (cleavage-stage) zebrafish embryos (critical aquatic and eco- species) as in vivo model organisms to probe the diffusion and toxicity of Ag NPs. We found that single Ag NPs (30-72 nm diameters) passively diffused into the embryos through chorionic pores via random Brownian motion and stayed inside the embryos throughout their entire development (120 hours-post-fertilization, hpf). Dose-and size-dependent toxic effects of the NPs on embryonic development were observed, showing the possibility of tuning biocompatibility and toxicity of the NPs. At lower concentrations of the NPs (≤0.02 nM), 75-91% of embryos developed into normal zebrafish. At the higher concentrations of NPs (≥0.20 nM), 100% of embryos became dead. At the concentrations in between (0.02-0.2 nM), embryos developed into various deformed zebrafish. Number and sizes of individual Ag NPs embedded in tissues of normal and deformed zebrafish at 120 hpf were quantitatively analyzed, showing deformed zebrafish with higher number of larger NPs than normal zebrafish and size-dependent nanotoxicity. By comparing with our previous studies of smaller Ag NPs (11.6 ± 3.5 nm), we found striking size-dependent nanotoxicity that, at the same molar concentration, the larger Ag NPs (41.6 ± 9.1 nm) are more toxic than the smaller Ag NPs (11.6 ± 3.5 nm)

Modulation of EEG spectral edge frequency during patterned pneumatic oral stimulation in preterm infants

Background—Stimulation of the nervous system plays a central role in brain development and neurodevelopmental outcome. Thalamocortical and corticocortical development is diminished in premature infants and correlated to electroencephalography (EEG) progression. The purpose of this study was to determine the effects of orocutaneous stimulation on the modulation of spectral edge frequency, fc=90% (SEF-90) derived from EEG recordings in preterm infants. Methods—Twenty two preterm infants were randomized to experimental and control conditions. Pulsed orocutaneous stimulation was presented during gavage feedings begun at around 32 weeks postmenstrual age (PMA). The SEF-90 was derived from 2-channel EEG recordings. Results—Compared to the control condition, the pulsed orocutaneous stimulation produced a significant reorganization of SEF-90 in the left (p = 0.005) and right (p \u3c 0.0001) hemispheres. Notably, the left and right hemisphere showed a reversal in the polarity of frequency shift, demonstrating hemispheric asymmetry in the frequency domain. Pulsed orocutaneous stimulation also produced a significant pattern of short term cortical adaptation and a long term neural adaptation manifest as a 0.5 Hz elevation in SEF-90 after repeated stimulation sessions. Conclusion—This is the first study to demonstrate the modulating effects of a servo-controlled oral somatosensory input on the spectral features of EEG activity in preterm infants

Investigation of Grooved Circular Jet Flow Experimentally and Using Computational Fluid Dynamics

This study is the investigation of grooved circular jet flow experimentally and using computational fluid dynamics (CFD). Experimental studies were conducted by using straight circular and grooved circular tubes in a multi-purpose low-range subsonic wind tunnel. Single channel hot wire anemometer was used in turbulence measurements. Numerical studies for the solution of jet flow were performed through FLUENT program (ANSYS 14.5). Jet flow profiles at different velocities were formed by using the data generated at predetermined stations in the experiment room for the straight circular tubes and grooved circular tubes. After transferring the experimental data to Fluent, jet exit points of the circular tubes were placed in the quarter model to coincide with the initial coordinates of experimental room. CFD Calculations were done by implementing different velocities in the experimental room and the jet. Jet flow structures obtained from both computational and experimental calculations are shown in graphs and the data is presented in Tables. The obtained parameters are as follows: axis velocity ($U_\text{e}$), root mean square velocity ($U_\text{rms}$), turbulence velocity ($U_\text{turb}$), jet half width (b) and Reynolds numbers ($Re_{D}$ and $Re_{b}$). These parameters were calculated with reference to jet radius and jet half width. Graphics formed by the generated non-dimensional data were compared to the previous studies