On Legendrian Embbeddings into Open Book Decompositions

We study Legendrian embeddings of a compact Legendrian submanifold $L$ sitting in a closed contact manifold $(M,\xi)$ whose contact structure is supported by a (contact) open book $\mathcal{OB}$ on $M$. We prove that if $\mathcal{OB}$ has Weinstein pages, then there exist a contact structure $\xi'$ on $M$, isotopic to $\xi$ and supported by $\mathcal{OB}$, and a contactomorphism $f:(M,\xi) \to (M,\xi')$ such that the image $f(L)$ of any such submanifold can be Legendrian isotoped so that it becomes disjoint from the closure of a page of $\mathcal{OB}$.Comment: 14 pages, 4 figures. Major corrections made. arXiv admin note: substantial text overlap with arXiv:1003.220

Proteostasis and ageing: insights from long-lived mutant mice

The global increase in life expectancy is creating significant medical, social and economic challenges to current and future generations. Consequently, there is a need to identify the fundamental mechanisms underlying the ageing process. This knowledge should help develop realistic interventions capable of combatting age-related disease, and thus improving late-life health and vitality. While several mechanisms have been proposed as conserved lifespan determinants, the loss of proteostasis- where proteostasis is defined here as the maintenance of the proteome- appears highly relevant to both ageing and disease. Several studies have shown that multiple proteostatic mechanisms, including the endoplasmic reticulum (ER)-induced unfolded protein response (UPR), the ubiquitin-proteasome system (UPS) and autophagy, all appear indispensable for longevity in many long-lived invertebrate mutants. Similarly, interspecific comparisons suggest that proteostasis may be an important lifespan determinant in vertebrates. Over the last 20 years a number of long-lived mouse mutants have been described, many of which carry single-gene mutations within the growth-hormone, insulin/IGF-1 or mTOR signalling pathways. However, we still do not know how these mutations act mechanistically to increase lifespan and healthspan, and accordingly whether mechanistic commonality occurs between different mutants. Recent evidence supports the premise that the successful maintenance of the proteome during ageing may be linked to the increased lifespan and healthspan of long-lived mouse mutants

Statistical Confirmation of a Stellar Upper Mass Limit

We derive the expectation value for the maximum stellar mass (m_max) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N. We statistically demonstrate that the upper IMF of the local massive star census observed thus far in the Milky Way and Magellanic Clouds clearly exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter IMF, although the result is more ambiguous for a steeper IMF.Comment: PDF, 5 pages, 4 figures. Accepted to the Astrophysical Journal Letter

The star formation process in the Magellanic Clouds

The Magellanic Clouds offer unique opportunities to study star formation both on the global scales of an interacting system of gas-rich galaxies, as well as on the scales of individual star-forming clouds. The interstellar media of the Small and Large Magellanic Clouds and their connecting bridge, span a range in (low) metallicities and gas density. This allows us to study star formation near the critical density and gain an understanding of how tidal dwarfs might form; the low metallicity of the SMC in particular is typical of galaxies during the early phases of their assembly, and studies of star formation in the SMC provide a stepping stone to understand star formation at high redshift where these processes can not be directly observed. In this review, I introduce the different environments encountered in the Magellanic System and compare these with the Schmidt-Kennicutt law and the predicted efficiencies of various chemo-physical processes. I then concentrate on three aspects that are of particular importance: the chemistry of the embedded stages of star formation, the Initial Mass Function, and feedback effects from massive stars and its ability to trigger further star formation.Comment: 12pages, 5figures, invited review at the IAUS 256, The Magellanic System: Stars, Gas, and Galaxies, eds. Jacco van Loon, Joana Oliveir

RITUXIMAB DELAYS WOUND HEALING AND DECREASES WHITE BLOOD CELL COUNT IN MALE MICE

ABSTRACTObjective: The aims of this research are to evaluate the effect of rituximab on wound healing, some hematological parameters, histological changes inwound healing, and histopathological changes in some organs in male mice.Methods: Totally, 15 adult male mice (25-30 g) were enrolled in this study. Animals were kept in the animal house College of Medicine/Universityof Babylon, and the temperature was controlled on 25°C and 14 hrs light and 10 hrs dark cycles. The animals were provided with standard diet andwater ad libitum. The animals were divided randomly into 3 groups, five mice in each group, Group 1 (control group) received no treatment, Group 2received rituximab 1 m/kg, IP, at days 0, 5, and 10 after wounding, in Group 3, rituximab was topically applied to the wound at days 0, 5, and 10 afterwounding.Results: The results yield that the wound healing significantly decreased (p<0.05) in Groups 2 and 3 as compared to control group. While the resultsregarding white blood cells (WBCs) count, there is a significant decrease in WBC count in Group 2 (p>0.05). Platelets and red blood cell count insignificantly increased in Group 3 as compared to control group (p<0.05). There were no histopathological changes in the skin, kidneys, and spleen.In liver, nonsignificant histopathological changes (p>0.05) found in Group 2 and 3 as compared to control group.Conclusion: Rituximab delays wound healing and reduces WBC count in male mice.Keywords: Rituximab, Wound healing, Lymphocyte, CD20, White blood cells, Mice

Use of the normal distribution in the study of simple stepwise equilibria

AbstractThe normal distribution is used to estimate the pH range for the existence of metal ion concentrations in hydrolysis reactions. The standard deviation of the metal ion concentration is expressed as a function of the formation constant for the reaction. An example is presented using data for the equilibrium reaction Hg+2 + OH-1 ⇌ Hg(OH)+