Role of the cellular environment in interstitial stem cell proliferation in Hydra

The role of the cellular environment on hydra stem cell proliferation and differentiation was investigated by introduction of interstitial cells into host tissue of defined cellular composition. In epithelial tissue lacking all non-epithelial cells the interstitial cell population did not grow but differentiated into nerve cells and nematocytes. In host tissue with progressively increased numbers of nerve cells growth of the interstitial cell population was positively correlated to the nerve cell density. In agreement with previous observations (Bode et al. 1976), growth of the interstitial cell population was also found to be negatively correlated to the level of interstitial cells present. The strong correlation between the growth of the interstitial cell population and the presence of interstitial cells and nerve cells implies that interstitial cell proliferation is controlled by a feedback signal from interstitial cells and their derivatives. Our results suggest that the cellular environment of interstitial cells provides cues which are instrumental in stem cell decision making

Catalytic role of boron atoms in self-interstitial clustering in Si

Using density functional theory (DFT) calculations and kinetic simulations, we have investigated the influence of boron atoms on self-interstitial clustering in Si. From DFT calculations of neutral interstitial clusters with a single B atom (BsIn, nIn–1 + BsI) becomes substantially weaker than that of an interstitial (BsIn-->BsIn–1 + I) when n>=4. This implies boron can be liberated while leaving an interstitial cluster behind. Our kinetic simulations including the boron liberation explain well experimental observations reported by J. L. Benton et al., J. Appl. Phys. 82, 120 (1997)

Cloned interstitial stem cells grow as contiguous patches in hydra

The migration of interstitial cells was analyzed during the growth of stem cell clones in vivo. The spatial distribution of cloned cells was analyzed at a time by which extensive migration of interstitial cells could have occurred. All interstitial cell clones were found to form large contiguous patches of cells. The results indicate that there is little migration of large interstitial cells in undisturbed tissue during normal growth. This finding is surprising since numerous grafting experiments have shown extensive migration of these cells. The implications of finding nonrandomly distributed stem cells are discussed

Recent advances in interstitial lung disease research

The interstitial lung diseases are a diverse collection of disorders characterized by impaired gas exchange, restricted physiology on lung function testing, and diffuse parenchymal lung infiltrates on radiography. Although the interstitial lung diseases are many, in routine clinical practice, the most commonly encountered in general internal medicine practice are sarcoidosis, idiopathic pulmonary fibrosis, and connective tissue disease-associated interstitial lung diseases. In immunocompromised patients, infection is the most common cause of diffuse lung infiltrates and must be ruled out before any attempt to treat with immune altering agents like corticosteroids. This review will focus on the more clinically significant recent advances in the broad field of interstitial lung disease research, with emphasis on the more common interstitial lung diseases occurring in immunocompetent hosts.peer-reviewe

Dopant-Dopant Interactions in Beryllium doped Indium Gallium Arsenide: an Ab Initio Study

We present an ab initio study of dopant-dopant interactions in beryllium-doped InGaAs. We consider defect formation energies of various interstitial and substitutional defects and their combinations. We find that all substitutional-substitutional interactions can be neglected. On the other hand, interactions involving an interstitial defect are significant. Specially, interstitial Be is stabilized by about 0.9/1.0 eV in the presence of one/two BeGa substitutionals. Ga interstitial is also substantially stabilized by Be interstitials. Two Be interstitials can form a metastable Be-Be-Ga complex with a dissociation energy of 0.26 eV/Be. Therefore, interstitial defects and defect-defect interactions should be considered in accurate models of Be doped InGaAs. We suggest that In and Ga should be treated as separate atoms and not lumped into a single effective group III element, as has been done before. We identified dopant-centred states which indicate the presence of other charge states at finite temperatures, specifically, the presence of Beint+1 (as opposed to Beint+2 at 0K)