3,731 research outputs found
Regenerative medicine for childhood gastrointestinal diseases
Several paediatric gastrointestinal diseases result in life-shortening organ failure. For many of these conditions, current therapeutic options are suboptimal and may not offer a cure. Regenerative medicine is an inter-disciplinary field involving biologists, engineers, and clinicians that aims to produce cell and tissue-based therapies to overcome organ failure. Exciting advances in stem cell biology, materials science, and bioengineering bring engineered gastrointestinal cell and tissue therapies to the verge of clinical trial. In this review, we summarise the requirements for bioengineered therapies, the possible sources of the various cellular and non-cellular components, and the progress towards clinical translation of oesophageal and intestinal tissue engineering to date
Potassium Abundances in Red Giants of Mildly to Very Metal-Poor Globular Clusters
A non-LTE analysis of K I resonance lines at 7664.91 and 7698.97 A was
carried out for 15 red giants belonging to three globular clusters of different
metallicity (M 4, M 13, and M 15) along with two reference early-K giants (rho
Boo and alpha Boo), in order to check whether the K abundances are uniform
within a cluster and to investigate the behavior of [K/Fe] ratio at the
relevant metallicity range of -2.5 <[Fe/H] < -1. We confirmed that [K/H] (as
well as [Fe/H]) is almost homogeneous within each cluster to a precision of <
~0.1 dex, though dubiously large deviations are exceptionally seen for two
peculiar stars showing signs of considerably increased turbulence in the upper
atmosphere. The resulting [K/Fe] ratios are mildly supersolar by a few tenths
of dex for three clusters, tending to gradually increase from ~+0.1-0.2 at
[Fe/H] ~-1 to ~+0.3 at [Fe/H] ~ -2.5. This result connects reasonably well with
the [K/Fe] trend of disk stars (-1 < [Fe/H]) and that of extremely metal-poor
stars (-4 <[Fe/H] < -2.5). That is, [K/Fe] appears to continue a gradual
increase from [Fe/H]~0 toward a lower metallicity regime down to [Fe/H]~-3,
where a broad maximum of [K/Fe]~+0.3-0.4 is attained, possibly followed by a
slight downturn at [Fe/H]<~-3.Comment: 13 pages, 4 tables, 6 figures, and 1 electronic table (accepted for
publication in Publ. Astron. Soc. Japan
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