Boundedness, compactness and Schatten-class membership of weighted composition operators

The boundedness and compactness of weighted composition operators on the Hardy space ${\mathcal H}^2$ of the unit disc is analysed. Particular reference is made to the case when the self-map of the disc is an inner function. Schatten-class membership is also considered; as a result, stronger forms of the two main results of a recent paper of Gunatillake are derived. Finally, weighted composition operators on weighted Bergman spaces $\mathcal{A}^2 \alpha(\mathbb{D})$ are considered, and the results of Harper and Smith, linking their properties to those of Carleson embeddings, are extended to this situation.Comment: 12 page

Stem Cell Transplantation Increases Antioxidant Effects in Diabetic Mice

Intra bone marrow-bone marrow transplantation (IBM- BMT) + thymus transplantation (TT) has been shown to reduce the incidence of graft versus host disease (GVHD) and restore donor-derived T cell function. In addition, an increase in insulin sensitivity occurred in db/db mice after IBM-BMT+TT treatment. Heme oxygenase (HO)-1 is a stress inducible enzyme which exert antioxidant, antiapoptotic, and immune-modulating properties. We examined whether IBM-BMT+TT could modulate the expression of HO-1 in the kidneys of db/db mice. Six-week-old db/db mice with blood glucose levels higher than 250 mg/dl were treated with IBM-BMT+TT. Six weeks later, the db/db mice showed decreased body weight, blood glucose levels and insulin, and increased plasma adiponectin levels. The upregulation of HO-1 was associated with significantly (p\u3c0.05) increased levels of peNOS and pAKT, but decreased levels of iNOS in the kidneys of db/db mice. Plasma creatinine levels also decreased (p\u3c0.05), and the expression of type IV collagen was improved. Thus IBM-BMT+TT unregulated the expression of HO-1, peNOS and pAKT, while decreasing iNOS levels in the kidney of db/db mice. This was associated with an improvement in renal function

Identification of a pool of non-pumping Na/K-ATPase

Recent studies have ascribed many non-pumping functions to the Na/K-ATPase. Here, we present experimental evidence demonstrating that over half of the plasma membrane Na/KATPase in LLC-PK1 cells is performing cellular functions other than ion pumping. This “non-pumping” pool of Na/K-ATPase, like the pumping pump, binds ouabain. Depletion of either cholesterol or caveolin-1 moves some of the “non-pumping” Na/KATPase into the pumping pool. Graded knock-down of the 1 subunit of the Na/K-ATPase eventually results in loss of this “non-pumping” pool while preserving the pumping pool. Our prior studies indicate that a loss of the non-pumping pool is associated with a loss of receptor function as evidenced by the failure of ouabain administration to induce the activation of Src and/or ERK. Therefore, our new findings suggest that a substantial amount of surface-expressed Na/K-ATPase, at least in some types of cells, may function as non-canonical ouabain-binding receptors

Cyclooxygenase-2 dependent metabolism of 20-HETE increases adiposity and adipocyte enlargement in mesenchymal stem cell-derived adipocytes

Abstract 20-Hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE), a product of the cytochrome P450 (CYP)-catalyzed [1] -hydroxylation of arachidonic acid, induces oxidative stress and, in clinical studies, is associated with increased body mass index (BMI) and the metabolic syndrome. This study was designed to examine the effects of exogenous 20- HETE on mesenchymal stem cell (MSC)-derived adipocytes. The expression levels of CYP4A11 and CYP4F2 (major 20-HETE synthases in humans) in MSCs decreased during adipocyte differentiation; however, exogenous administration of 20-HETE (0.1–1 M) increased adipogenesis in a dose dependent manner in these cells ( P \u3c 0.05). The inability of a 20-HETE analog to reproduce these effects suggested the involvement of a metabolic product of 20-HETE in mediating its pro-adipogenic effects. A cyclooxygenase (COX)-1 selective inhibitor enhanced, whereas a COX-2 selective or a dual COX-1/2 inhibitor attenuated adipogenesis induced by 20-HETE. The COX-derived metabolite of 20-HETE, 20-OH-PGE 2 , enhanced adipogenesis and lipid accumulation in MSCs. The pro-adipogenic effects of 20-HETE and 20-OH-PGE 2 resulted in the increased expression of the adipogenic regulators PPAR and -catenin in MSC-derived adipocytes. Taken together we show for the fi rst time that 20-HETE-derived COX-2-dependent 20-OH-PGE 2 enhances mature infl amed adipocyte hypertrophy in MSC undergoing adipogenic differentiation. — Kim, D. H., N. Puri, K. Sodhi, J. R. Falck, N. G. Abraham, J. Shapiro, and M. L. Schwartzman. Cyclooxygenase-2 dependent metabolism of 20-HETE increasesadiposity and adipocyte enlargement in mesenchymal stem cell-derived adipocytes

Long-distance dispersal of pigeons and doves generated new ecological opportunities for host-switching and adaptive radiation by their parasites.

Adaptive radiation is an important mechanism of organismal diversification and can be triggered by new ecological opportunities. Although poorly studied in this regard, parasites are an ideal group in which to study adaptive radiations because of their close associations with host species. Both experimental and comparative studies suggest that the ectoparasitic wing lice of pigeons and doves have adaptively radiated, leading to differences in body size and overall coloration. Here, we show that long-distance dispersal by dove hosts was central to parasite diversification because it provided new ecological opportunities for parasites to speciate after host-switching. We further show that among extant parasite lineages host-switching decreased over time, with cospeciation becoming the more dominant mode of parasite speciation. Taken together, our results suggest that host dispersal, followed by host-switching, provided novel ecological opportunities that facilitated adaptive radiation by parasites

Quantum-Noise Reduction in a Driven Cavity with Feedback

We show that amplitude-squeezed states may be produced by driving a feedback-controlled cavity with a coherent input signal. The feedback controls the transmissivity of one output from the cavity and is essentially equivalent to nonlinear absorption. The cavity effectively acts as a nonlinear reflector. Hence, amplitude-squeezed states with arbitrarily strong coherent intensities can be obtained

Relativistic Models for Binary Neutron Stars with Arbitrary Spins

We introduce a new numerical scheme for solving the initial value problem for quasiequilibrium binary neutron stars allowing for arbitrary spins. The coupled Einstein field equations and equations of relativistic hydrodynamics are solved in the Wilson-Mathews conformal thin sandwich formalism. We construct sequences of circular-orbit binaries of varying separation, keeping the rest mass and circulation constant along each sequence. Solutions are presented for configurations obeying an n=1 polytropic equation of state and spinning parallel and antiparallel to the orbital angular momentum. We treat stars with moderate compaction ((m/R) = 0.14) and high compaction ((m/R) = 0.19). For all but the highest circulation sequences, the spins of the neutron stars increase as the binary separation decreases. Our zero-circulation cases approximate irrotational sequences, for which the spin angular frequencies of the stars increases by 13% (11%) of the orbital frequency for (m/R) = 0.14 ((m/R) = 0.19) by the time the innermost circular orbit is reached. In addition to leaving an imprint on the inspiral gravitational waveform, this spin effect is measurable in the electromagnetic signal if one of the stars is a pulsar visible from Earth.Comment: 21 pages, 14 figures. A few explanatory sentences added and some typos corrected. Accepted for publication in Phys. Rev.

Prieurianin Causes Weight Loss in Diet-Induced Obese Mice and Inhibits Adipogenesis in Cultured Preadipocytes

The global increase in the incidence of obesity has emerged as one of the most serious public health risks in recent years. Despite the enormity of the obesity pandemic, there are currently only two FDA-approved therapies for its treatment and these drugs exhibit modest effi cacy and have limiting side effects. Prieurianin is a plant limonoid product that deters feeding in insect larvae. We investigated in this study the effects of prieurianin on weight loss and adipogenesis. Our results showed that prieurianin causes weight loss by reducing energy intake in obese mice on highcalorie diet. We also found that prieurianin is anti-adipogenic in cultured preadipocytes and adipocytes by inhibiting proliferation and differentiation of preadipocytes into adipocytes, and induces either dedifferentiation or delipidation of mature adipocytes. Whether prieurianin can potentially be used for obesity treatment in human warrants further investigation

Principles of Quantitative Fluid and Cation Replacement in Extreme Hyperglycemia

Hyperglycemia may cause profound deficits of water, sodium and potassium through osmotic diuresis, which continues during treatment as long as there is glucosuria. Replacement fluids should cover both the deficits at presentation and the ongoing losses during treatment. At presentation with hyperglycemia, quantitative estimates of the deficits in water, sodium and potassium are based on rapid body weight changes, which indicate changes in body water, and on the serum sodium concentration corrected to a normal serum glucose level. The corrected serum sodium concentration provides a measure of the water deficit relative to the cation deficit (sodium, plus potassium) that is useful in guiding the choice of monovalent cation concentration in the initial replacement fluids. Monitoring clinical status, serum chemistries (glucose, sodium, potassium, total carbon dioxide), urine flow rate, and urine chemistries (sodium and potassium) during the course of fluid and cation replacement therapy is critical. This monitoring guides the volume and composition of replacement solutions for deficits developing during treatment and the management of potassium balance and acid-base abnormalities, including metabolic acidosis, respiratory acidosis, rarely, and others