Highly epitaxial LaBaCo2O5.5+δ (LBCO) thin films were grown on different miscut (001) SrTiO3 substrates (miscut angle of 0.5°, 3.0°, and 5.0°) to study the substrate surface step terrace effect on ...the in-plane electrical transport properties. The microstructure studies by X-ray diffraction and transmission electron microscopy indicate that the as-grown films are A-site disordered cubic perovskite structures with the c-axis highly oriented along the film growth direction. The four-probe scanning tunneling microscopy (STM) studies show that the LBCO thin films grown on the vicinal SrTiO3 substrates have a typical semiconductor behavior with the substrate surface terrace step inducing anisotropic electronic transport properties. These results indicate that in highly epitaxial thin films the surface terrace step induced local strains can play an important role in controlling the electronic transport properties and the anisotropic nature.
Objectives
To investigate effects of TiO2 nanotubes of different diameters on J744A.1 macrophage behaviour, secretion and expression of pro‐inflammatory cytokines and chemokines.
Materials and ...methods
Macrophage‐like J744A.1 cells were cultured on three types of Ti surface: mechanically polished titanium plus 30 and 80 nm TiO2 nanotube surfaces, for 4, 24 and 48 h. Macrophage adhesion and proliferation were assessed using CCK‐8 assay. Levels of pro‐inflammatory cytokines (TNF‐α, IL‐1β and IL‐6) and chemokines (MCP‐1 and MIP‐1α) secreted into the supernatant were measured using the Cytometric Bead Arrays kit. TNF‐α, MCP‐1 and MIP‐1α gene expression were quantitatively analysed by real‐time PCR.
Results
These show that TiO2 nanotube surfaces, especially of 80 nm TiO2 nanotube, benefited macrophage adhesion and proliferation, and reduced protein secretion and mRNA expression of TNF‐α, MCP‐1 and MIP‐1α. IL‐1β and IL‐6 were undetectable on all the surfaces at all times.
Conclusions
TiO2 nanotube surfaces, especially of 80 nm TiO2 nanotube, reduced inflammatory response in vitro, which might be part of a basis for rapid osseointegration in implants with TiO2 nanotube surfaces in animal studies.
We investigated the role of regionally discrete GABA (gamma-aminobutyric acid) receptors in the sedative response to pharmacological agents that act on GABA(A) receptors (muscimol, propofol and ...pentobarbital; 'GABAergic agents') and to ketamine, a general anesthetic that does not affect GABA(A) receptors. Behavioral studies in rats showed that the sedative response to centrally administered GABAergic agents was attenuated by the GABA(A) receptor antagonist gabazine (systemically administered). The sedative response to ketamine, by contrast, was unaffected by gabazine. Using c-Fos as a marker of neuronal activation, we identified a possible role for the tuberomammillary nucleus (TMN): when gabazine was microinjected directly into the TMN, it attenuated the sedative response to GABAergic agents. Furthermore, the GABA(A) receptor agonist muscimol produced a dose-dependent sedation when it was administered into the TMN. We conclude that the TMN is a discrete neural locus that has a key role in the sedative response to GABAergic anesthetics.
Nuclear Charge Radius of {sup 8}He Mueller, P.; Bailey, K.; Holt, R. J. ...
Physical review letters,
12/2007, Letnik:
99, Številka:
25
Journal Article
Recenzirano
Odprti dostop
The root-mean-square (rms) nuclear charge radius of {sup 8}He, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms ...charge radius of {sup 6}He was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from {sup 6}He to {sup 8}He is an indication of the change in the correlations of the excess neutrons and is consistent with the {sup 8}He neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.
A recent genome‐wide association study discovered that two polymorphisms, interferon (IFN) alpha receptor 2 (IFNAR‐2) F8S and interleukin 10 receptor (IL10RB) K47E, were associated with ...susceptibility to hepatitis B virus (HBV) infection in Africa. Here, we reevaluate the effects of the two polymorphisms on HBV susceptibility in the Chinese Han population, and extended the study to look at their association with IFN response in chronic hepatitis B (CHB). We included 341 patients with CHB and 341 unrelated controls presenting with asymptotic HBV self‐limited infection, who were well matched in age and sex. In the CHB group, 101 patients had been treated with peg‐IFN‐alpha‐2a for 48 weeks and followed up for 24 weeks to determine the clinical response, resulting 34 individuals with sustained virological response (SVR) and 67 individuals with nonsustained response (NR). Subgroups in the CHB group were divided according to the viral loads, HBeAg and maternal HBsAg status. The association with the susceptibility to HBV infection was only observed for IL10RB K47E when we compared the individuals with persistent HBV infection through nonmaternal transmission to the controls with asymptomatic self‐limited HBV infection. Further, we found that the IFNAR2‐8SS genotype was associated with HBeAg negative patients (OR = 0.316, 95% CI: 0.121–0.825, P = 0.019) and that the IFNAR2‐8F allele was associated with the risk to high viral loads (OR = 1.667, 95% CI: 1.148–2.420, P = 0.007). In addition, the IFNAR2‐8FF genotype predisposed to higher MxA gene induction and correlated with sustained IFN response (OR = 0.348, 95% CI: 0.129–0.935, P = 0.036). Haplotype analysis based on polymorphisms of three single‐nucleotide polymorphisms, MxA −88 G/T, IFNAR‐2 F8S and IL10RB K47E showed that the haplotype distribution was significantly different between the SVR and NR groups (P = 0.040). This study suggests that IFNAR2 may play an important role in determining IFN response and clinical phenotypes of HBV infection in the Chinese Han population.
The spontaneous rhythmic firing of action potentials in pacemaker neurons depends on the biophysical properties of voltage‐gated ion channels and background leak currents. The background leak current ...includes a large K+ and a small Na+ component. We previously reported that a Na+‐leak current via U‐type channels is required to generate spontaneous action potential firing in the identified respiratory pacemaker neuron, RPeD1, in the freshwater pond snail Lymnaea stagnalis. We further investigated the functional significance of the background Na+ current in rhythmic spiking of RPeD1 neurons. Whole‐cell patch‐clamp recording and computational modeling approaches were carried out in isolated RPeD1 neurons. The whole‐cell current of the major ion channel components in RPeD1 neurons were characterized, and a conductance‐based computational model of the rhythmic pacemaker activity was simulated with the experimental measurements. We found that the spiking rate is more sensitive to changes in the Na+ leak current as compared to the K+ leak current, suggesting a robust function of Na+ leak current in regulating spontaneous neuronal firing activity. Our study provides new insight into our current understanding of the role of Na+ leak current in intrinsic properties of pacemaker neurons.
Simulation modeling showing that spiking activity is more sensitive to changes in Na+ leak current than in K+ leak current. (A and B) 3D heat‐map plots showing rhythmic spiking duration generated during RPeD1 simulations using different settings for gLNa and gLK, respectively. (C and D) Corresponding spike rates for the range of simulated conductance (blue), and the spike rate sensitivity (green) to changes in conductance of Na+ leak current and K+ leak current, respectively. (E) Heat map plot of spike rate (Hz), as a function of Na+ leak current conductance (gLNa, Y) to K+ leak current conductance (gLK, X) ratio. High firing frequency was observed at low K+ leak conductance, and the firing threshold is dependent on the Na+ leak conductance.
Based on results from more than 300 specimens of fiber reinforced polymer (FRP) confined concrete cylinders covering a wide range of parameters, the confinement effect and failure mechanisms are ...analyzed. Special attention is given to predict whether FRP-confined concrete cylinder has a strain-hardening or a strain-softening response. In the case of FRP-confined concrete cylinder with a strain-hardening response, it is found that the ultimate Poisson’s ratio of FRP-confined concrete trends to an asymptotic value. Through calculation of the ultimate Poisson’s ratio, and according to strain compatibility, the ultimate strain of FRP-confined concrete can be predicted. Moreover, by comparing with a lot of existing experimental data, the proposed models are quite simple and still accurate enough, which can be applied to the concrete cylinders confined with various types of FRP composites. Besides, for the case of FRP-confined concrete cylinder with a strain-softening response, equations for predicting the maximum strength, peak strain, ultimate strength and ultimate strain are suggested in this paper.
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