Tissue engineering: construction of a multicellular 3D scaffold for the delivery of layered cell sheets.

Many tissues, such as the adult human hearts, are unable to adequately regenerate after damage.(2,3) Strategies in tissue engineering propose innovations to assist the body in recovery and repair. For example, TE approaches may be able to attenuate heart remodeling after myocardial infarction (MI) and possibly increase total heart function to a near normal pre-MI level.(4) As with any functional tissue, successful regeneration of cardiac tissue involves the proper delivery of multiple cell types with environmental cues favoring integration and survival of the implanted cell/tissue graft. Engineered tissues should address multiple parameters including: soluble signals, cell-to-cell interactions, and matrix materials evaluated as delivery vehicles, their effects on cell survival, material strength, and facilitation of cell-to-tissue organization. Studies employing the direct injection of graft cells only ignore these essential elements.(2,5,6) A tissue design combining these ingredients has yet to be developed. Here, we present an example of integrated designs using layering of patterned cell sheets with two distinct types of biological-derived materials containing the target organ cell type and endothelial cells for enhancing new vessels formation in the "tissue". Although these studies focus on the generation of heart-like tissue, this tissue design can be applied to many organs other than heart with minimal design and material changes, and is meant to be an off-the-shelf product for regenerative therapies. The protocol contains five detailed steps. A temperature sensitive Poly(N-isopropylacrylamide) (pNIPAAM) is used to coat tissue culture dishes. Then, tissue specific cells are cultured on the surface of the coated plates/micropattern surfaces to form cell sheets with strong lateral adhesions. Thirdly, a base matrix is created for the tissue by combining porous matrix with neovascular permissive hydrogels and endothelial cells. Finally, the cell sheets are lifted from the pNIPAAM coated dishes and transferred to the base element, making the complete construct

The reset inflation puzzle and the heterogeneity in price stickiness

PublishedThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.New Keynesian models have been criticised on the grounds that they require implausibly large price shocks to explain inflation. Bils et al. (2012) show that, while these shocks are needed to reduce the excessive inflation persistence generated by the models, they give rise to unrealistically volatile reset price inflation. This paper shows that introducing heterogeneity in price stickiness in the models overcomes these criticisms directed at them. The incorporation of heterogeneity in price stickiness reduces the need for large price shocks. With smaller price shocks, the new model comes close to matching the data on reset inflation

The curious time lags of PG 1244+026: Discovery of the iron K reverberation lag

High-frequency iron K reverberation lags, where the red wing of the line responds before the line centroid, are a robust signature of relativistic reflection off the inner accretion disc. In this letter, we report the discovery of the Fe K lag in PG 1244+026 from ~120 ks of data (1 orbit of the XMM-Newton telescope). The amplitude of the lag with respect to the continuum is 1000 s at a frequency of ~1e-4 Hz. We also find a possible frequency-dependence of the line: as we probe higher frequencies (i.e. shorter timescales from a smaller emitting region) the Fe K lag peaks at the red wing of the line, while at lower frequencies (from a larger emitting region) we see the dominant reflection lag from the rest frame line centroid. The mean energy spectrum shows a strong soft excess, though interestingly, there is no indication of a soft lag. Given that this source has radio emission and it has little reported correlated variability between the soft excess and the hard band, we explore one possible explanation in which the soft excess in this source is dominated by the steep power-law like emission from a jet, and that a corona (or base of the jet) irradiates the inner accretion disc, creating the blurred reflection features evident in the spectrum and the lag. General Relativistic ray-tracing models fit the Fe K lag well, with the best-fit giving a compact X-ray source at a height of 5 gravitational radii and a black hole mass of 1.3e7 Msun.Comment: 6 pages, 6 figures, resubmitted to MNRAS after moderate revisions. This paper focuses on the discovery of the Fe K reverberation lag in PG 1244+026. We point the interested reader to Alston, Done & Vaughan (See today: arXiv:submit/0851673), which focuses on the soft lags in this sourc

Revealing the X-ray source in IRAS 13224-3809 through flux-dependent reverberation lags

IRAS 13224-3809 was observed in 2011 for 500 ks with the XMM-Newton observatory. We detect highly significant X-ray lags between soft (0.3 - 1 keV) and hard (1.2 - 5 keV) energies. The hard band lags the soft at low frequencies (i.e. hard lag), while the opposite (i.e. soft lag) is observed at high frequencies. In this paper, we study the lag during flaring and quiescent periods. We find that the frequency and absolute amplitude of the soft lag is different during high-flux and low-flux periods. During the low flux intervals, the soft lag is detected at higher frequencies and with smaller amplitude. Assuming that the soft lag is associated with the light travel time between primary and reprocessed emission, this behaviour suggests that the X-ray source is more compact during low-flux intervals, and irradiates smaller radii of the accretion disc (likely because of light bending effects). We continue with an investigation of the lag dependence on energy, and find that isolating the low-flux periods reveals a strong lag signature at the Fe K line energy, similar to results found using 1.3 Ms of data on another well known Narrow-Line Seyfert I galaxy, 1H0707-495.Comment: 6 pages, 8 figures, accepted for publication in MNRA

Effect of a three-month football training program on trace element metabolism of boys in the eight to twelve age group

This study was conducted to examine the effects of a three-month football training program on some trace elements in the serum in male kids aged between eight and twelve years. The study registered eight boys whose mean age was 10.25 ± 0.75 years, mean height was 138.63 ± 3.28 cm and mean weight was 32.13 ± 2.72 kg. The subjects were regularly trained in the accompaniment of coaches for three months (four to five days a week). Blood samples of 5 ml each were taken into plain tubes from the subjects twice, once at the beginning of the study and the other at the end of the three-month training sessions, after 12 h of nocturnal fasting. Serum cobalt (Co), cadmium (Cd), nickel (Ni), molybdenum (Mo), manganese (Mn), aluminum (Al), copper (Cu), zinc (Zn) and iron (Fe) levels were measured using an atomic absorption spectrophotometer. The results were expressed in mg/L. Cadmium, molybdenum, copper and zinc (p<0.05) values were measured after the study and were found significantly lower than those before the study. Results of this study demonstrate that three-month football training significantly reduced cadmium, molybdenum, copper and zinc values in eight to 12-year-old boys. The decrease in zinc levels in particular may be critical for the athletes health and performance.Key words: Football, boys, cadmium, molybdenum, copper, zinc

Does US monetary policy respond to oil and food prices?

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.A common view is that US monetary policy does not respond to changes in volatile energy and food prices. Despite this view, the popular New Keynesian models assume Taylor-type rules under which the short-term interest rates react to headline inflation. This paper evaluates the fit of alternative Taylor rules within an estimated New Keynesian model. A main finding is that the US central bank includes energy and food prices in its policy rule, although the weight assigned to these prices is much smaller than their share in the economy