Inflation and Dark Energy from spectroscopy at z > 2

The expansion of the Universe is understood to have accelerated during two epochs: in its very first moments during a period of Inflation and much more recently, at z < 1, when Dark Energy is hypothesized to drive cosmic acceleration. The undiscovered mechanisms behind these two epochs represent some of the most important open problems in fundamental physics. The large cosmological volume at 2 < z < 5, together with the ability to efficiently target high-$z$ galaxies with known techniques, enables large gains in the study of Inflation and Dark Energy. A future spectroscopic survey can test the Gaussianity of the initial conditions up to a factor of ~50 better than our current bounds, crossing the crucial theoretical threshold of $\sigma(f_{NL}^{\rm local})$ of order unity that separates single field and multi-field models. Simultaneously, it can measure the fraction of Dark Energy at the percent level up to $z = 5$, thus serving as an unprecedented test of the standard model and opening up a tremendous discovery space

Musashi 2 is a regulator of the HSC compartment identified by a retroviral insertion screen and knockout mice.

We used a retroviral integration screen to search for novel genes that regulate HSC function. One of the genes that conferred HSC dominance when overexpressed due to an adjacent retroviral insertion was Musashi 2 (Msi2), an RNA-binding protein that can act as a translational inhibitor. A gene-trap mouse model that inactivates the gene shows that Msi2 is more highly expressed in long-term (LT) and short-term (ST) HSCs, as well as in lymphoid myeloid primed progenitors (LMPPs), but much less in intermediate progenitors and mature cells. Mice lacking Msi2 are fully viable for up to a year or more, but exhibit severe defects in primitive precursors, most significantly a reduction in the number of ST-HSCs and LMPPs and a decrease in leukocyte numbers, effects that are exacerbated with age. Cell-cycle and gene-expression analyses suggest that the main hematopoietic defect in Msi2-defective mice is the decreased proliferation capacity of ST-HSCs and LMPPs. In addition, HSCs lacking Msi2 are severely impaired in competitive repopulation experiments, being overgrown by wild-type cells even when mutant cells were provided in excess. Our data indicate that Msi2 maintains the stem cell compartment mainly by regulating the proliferation of primitive progenitors downstream of LT-HSCs

Hypoglycemic effect of <it>Carica papaya</it> leaves in streptozotocin-induced diabetic rats

<p>Abstract</p> <p>Background</p> <p>Traditional plant treatment for diabetes has shown a surging interest in the last few decades. Therefore, the purpose of this study was to assess the hypoglycemic effect of the aqueous extract of <it>C. papaya</it> leaves in diabetic rats. Several studies have reported that some parts of the <it>C. papaya</it> plant exert hypoglycemic effects in both animals and humans.</p> <p>Methods</p> <p>Diabetes was induced in rats by intraperitoneal administration of 60 mg/kg of streptozotocin (STZ). The aqueous extract of <it>C. papaya</it> was administered in three different doses (0.75, 1.5 and 3 g/100 mL) as drinking water to both diabetic and non-diabetic animals during 4 weeks.</p> <p>Results</p> <p>The aqueous extract of <it>Carica papaya</it> (0.75 g and 1.5 g/100 mL) significantly decreased blood glucose levels (p<0.05) in diabetic rats. It also decreased cholesterol, triacylglycerol and amino-transferases blood levels. Low plasma insulin levels did not change after treatment in diabetic rats, but they significantly increased in non-diabetic animals. Pancreatic islet cells were normal in non-diabetic treated animals, whereas in diabetic treated rats, <it>C. papaya</it> could help islet regeneration manifested as preservation of cell size. In the liver of diabetic treated rats, <it>C. papaya</it> prevented hepatocyte disruption, as well as accumulation of glycogen and lipids. Finally, an antioxidant effect of <it>C. papaya</it> extract was also detected in diabetic rats.</p> <p>Conclusions</p> <p>This study showed that the aqueous extract of <it>C. papaya</it> exerted a hypoglycemic and antioxidant effect; it also improved the lipid profile in diabetic rats. In addition, the leaf extract positively affected integrity and function of both liver and pancreas.</p