Toric vector bundles and parliaments of polytopes

We introduce a collection of convex polytopes associated to a torus-equivariant vector bundle on a smooth complete toric variety. We show that the lattice points in these polytopes correspond to generators for the space of global sections and we relate edges to jets. Using the polytopes, we also exhibit toric vector bundles that are ample but not globally generated, and toric vector bundles that are ample and globally generated but not very ample.Comment: 24 pages, 5 figure

Linear Toric Fibrations

These notes are based on three lectures given at the 2013 CIME/CIRM summer school. The purpose of this series of lectures is to introduce the notion of a toric fibration and to give its geometrical and combinatorial characterizations. Polarized toric varieties which are birationally equivalent to projective toric bundles are associated to a class of polytopes called Cayley polytopes. Their geometry and combinatorics have a fruitful interplay leading to fundamental insight in both directions. These notes will illustrate geometrical phenomena, in algebraic geometry and neighboring fields, which are characterized by a Cayley structure. Examples are projective duality of toric varieties and polyhedral adjunction theory

Response to. comment on optic nerve sheath diameter ultrasound evaluation in intensive care unit: possible role and clinical aspects in neurological critical patients' daily monitoring

Comment on "Optic Nerve Sheath Diameter Ultrasound Evaluation in Intensive Care Unit: Possible Role and Clinical Aspects in Neurological Critical Patients' Daily Monitoring"

Enhancement of photoacoustic detection of inhomogeneities in polymers

We report a series of experiments on laser pulsed photoacoustic excitationin turbid polymer samples addressed to evaluate the sound speed in the samples and the presence of inhomogeneities in the bulk. We describe a system which allows the direct measurement of the speed of the detected waves by engraving the surface of the piece under study with a fiduciary pattern of black lines. We also describe how this pattern helps to enhance the sensitivity for the detection of an inhomogeneity in the bulk. These two facts are useful for studies in soft matter systems including, perhaps, biological samples. We have performed an experimental analysis on Grilon(R) samples in different situations and we show the limitations of the method.Comment: 8 pages, 7 figure

Apoptosis induced by a HIPK2 full-length-specific siRNA is due to off-target effects rather than prevalence of HIPK2-Δe8 isoform.

Small interfering RNAs (siRNAs) are widely used to study gene function and extensively exploited for their potential therapeutic applications. HIPK2 is an evolutionary conserved kinase that binds and phosphorylates several proteins directly or indirectly related to apoptosis. Recently, an alternatively spliced isoform skipping 81 nucleotides of exon 8 (Hipk2-∆e8) has been described. Selective depletion of Hipk2 full-length (Hipk2-FL) with a speci c siRNA that spares the Hipk2-∆e8 isoform has been shown to strongly induce apoptosis, suggesting an unpredicted dominant- negative effect of Hipk2-FL over the ∆e8 isoform. From this observation, we sought to take advantage and assessed the therapeutic potential of generating Hipk2 isoform unbalance in tumor-initiating cells derived from colorectal cancer patients. Strong reduction of cell viability was induced in vitro and in vivo by the originally described exon 8-speci c siRNA, supporting a potential therapeutic application. However, validation analyses performed with additional exon8-speci c siRNAs with different stabilities showed that all exon8-targeting siRNAs can induce comparable Hipk2 isoform unbalance but only the originally reported e8-siRNA promotes cell death. These data show that loss of viability does not depend on the prevalence of Hipk2- ∆e8 isoform but it is rather due to microRNA-like off-target effects

Poplar woody root proteome during the transition dormancy-active growth

Woody plants living in temperate climates finely regulate their growth and development in relation to seasonal changes; their transition from vegetative to dormancy phase represents an adaptation to their environment. Events occurring in the shoot during onset/release from dormancy have been largely investigated, whereas in woody roots they remain completely unknown. In recent years, we have been interested in understanding the molecular and physiological events occurring in poplar woody root during release from dormancy. Here, we propose the results of a comparative analysis of the proteome of poplar woody root sampled at different time points: T0 (dormancy condition), T1 (release from dormancy), and T2 (full vegetative condition). This study identified proteins that may be involved in the long-term survival of a dormant root or landmarking a specific time point

Cyclin D1 Restrains Oncogene-Induced Autophagy by Regulating the AMPK-LKB1 Signaling Axis.

Autophagy activated after DNA damage or other stresses mitigates cellular damage by removing damaged proteins, lipids, and organelles. Activation of the master metabolic kinase AMPK enhances autophagy. Here we report that cyclin D1 restrains autophagy by modulating the activation of AMPK. In cell models of human breast cancer or in a cyclin D1-deficient model, we observed a cyclin D1-mediated reduction in AMPK activation. Mechanistic investigations showed that cyclin D1 inhibited mitochondrial function, promoted glycolysis, and reduced activation of AMPK (pT172), possibly through a mechanism that involves cyclin D1-Cdk4/Cdk6 phosphorylation of LKB1. Our findings suggest how AMPK activation by cyclin D1 may couple cell proliferation to energy homeostasis

Evaluation of self-absorption of manganese emission lines in Laser Induced Breakdown Spectroscopy measurements

This paper is part of a more general study aimed to the determination of the best experimental procedures for reliable quantitative measurements of Fe-Mn alloys by LIBS. In this work, attention is pointed on the self-absorption processes, whose effect deeply influences the LIBS measurements, reflecting in non-linear calibration curves. The effect of self-absorption on the line intensity can be quantified by defining a self absorption coefficient, that measures the deviation of the line intensity from the linear extrapolation of the curve of growth in the optically thin regime. The authors demonstrated in a previous paper that self absorption coefficients could be calculated once the electron density of the plasma is known and the Stark coefficients of the lines are available. However, when the Stark coefficients of the lines of interest are not known, a different approach is needed. In this work a new method for evaluation of self absorption coefficients in LIBS measurements is presented, which does not require the knowledge of Stark coefficients. In order to understand the basic principles and setting out the theoretical tools that will be used for the analysis o f the alloys, a preliminary study was done on pure Mn; LIBS spectra were acquired in different experimental conditions, at different laser energies and different delays after the laser irradiation o f the sample. Moreover, collinear double pulse measurements were also performed. Analytical relations were derived and experimental procedures devised for evaluation o f the self absorption coefficients of several Mn lines, which are important for characterization and control of the experimental conditions in which the analysis is performed