Existence of the limit at infinity for a function that is integrable on the half line

It is well known that for a function that is integrable on [0,∞ ), its limit at infinity may not exist. First we illustrated this statement with an example. Then, we present conditions that guarantee the existence of the limit in the following two cases: When the integrable function is non-negative, if the first, second, third, or fourth, derivative is bounded in a neighborhood of each local maximum of f, then the limit exists. Without the non-negative constraint, if an integrable function has a bounded derivative on the entire interval [0,∞ ), then the limit exists

Microarray analysis of spring barley cultivars displaying differing sensitivity to physiological leaf spot (PLS)

peer-reviewedPhysiological leaf spot (PLS) is a disorder of spring barley (Hordeum vulgare L.), which has become more pronounced in recent years. The initial symptoms are small chlorotic/brown spots on the upper four leaves, which may develop into necrotic lesions with an irregular shape. As PLS occurs on leaves that are directly exposed to sunlight, it is thought that high light stress could be a trigger for the condition. This study concentrates on two cultivars, Cooper and Crusader, which display differential sensitivity to PLS. Biochemical measurements and enzyme assays revealed substantial difference in levels of ascorbate, type III peroxidases, and superoxide dismutase between the chosen cultivars during the 2003 growing season. A global gene expression study, using these field samples, was performed by microarray analysis. This supported the biochemical findings and highlighted additional sets of genes differentially expressed between the cultivars. Transcripts of particular interest, which appeared, included calcium signalling genes, cold-responsive genes and those involved in the assembly of Photosystem I. We conclude that susceptibility to PLS is related to levels of expression of genes with a role in countering the effects of oxidative stress.Teagasc Walsh Fellowship Programm

Phospholipase activation, free fatty acids and the proton permeability of a biological membrane

AbstractThe rate of collapse of a proton gradient across the apical membrane of rat kidney proximal tubule increases upon treatment with calcium, mercuric chloride and mellitin, substances which activate phospholipase A2. Treatment with phospholipase A2 or oleic acid also enhances the rate of proton gradient dissipation. Membrane water permeability is not affected. This phenomenon may have implications in pathological states arising from ischemia or toxic exposure

Spatial and Bidirectional Work Function Modulation of Monolayer Graphene with Patterned Polymer “Fluorozwitterists”

Understanding the electronic properties resulting from soft-hard material interfacial contact has elevated the utility of functional polymers in advanced materials and nanoscale structures, such as in work function engineering of two-dimensional (2D) materials to produce new types of high-performance devices. In this paper, we describe the electronic impact of functional polymers, containing both zwitterionic and fluorocarbon components in their side chains, on the work function of monolayer graphene through the preparation of negative-tone photoresists, which we term "fluorozwitterists." The zwitterionic and fluorinated groups each represent dipole-containing moieties capable of producing distinct surface energies as thin films. Kelvin probe force microscopy revealed these polymers to have a p-doping effect on graphene, which contrasts the work function decrease typically associated with polymer-to-graphene contact. Copolymerization of fluorinated zwitterionic monomers with methyl methacrylate and a benzophenone-substituted methacrylate produced copolymers that were amenable to photolithographic fabrication of fluorozwitterist structures. Consequently, spatial alteration of zwitterion coverage across graphene yielded stripes that resemble a lateral p-i-n diode configuration, with local increase or decrease of work function. Overall, this polymeric fluorozwitterist design is suitable for enabling simple, solution-based surface patterning and is anticipated to be useful for spatial work function modulation of 2D materials integrated into electronic devices

Informing Selection of Nanomaterial Concentrations for ToxCast in Vitro Testing Based on Occupational Exposure Potential

Background: Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable

Ozone depletion due to dust release of iodine in the free troposphere

Iodine is an atmospheric trace element emitted from oceans that efficiently destroys ozone (O3). Low O3 in airborne dust layers is frequently observed but poorly understood. We show that dust is a source of gas-phase iodine, indicated by aircraft observations of iodine monoxide (IO) radicals inside lofted dust layers from the Atacama and Sechura Deserts that are up to a factor of 10 enhanced over background. Gas-phase iodine photochemistry, commensurate with observed IO, is needed to explain the low O3 inside these dust layers (below 15 ppbv; up to 75% depleted). The added dust iodine can explain decreases in O3 of 8% regionally and affects surface air quality. Our data suggest that iodate reduction to form volatile iodine species is a missing process in the geochemical iodine cycle and presents an unrecognized aeolian source of iodine. Atmospheric iodine has tripled since 1950 and affects ozone layer recovery and particle formation.Fil: Koenig, Theodore K.. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados UnidosFil: Volkamer, Rainer. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados UnidosFil: Apel, Eric C.. National Center for Atmospheric Research; Estados UnidosFil: Bresch, James F.. National Center for Atmospheric Research; Estados UnidosFil: Cuevas, Carlos A.. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; EspañaFil: Dix, Barbara. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados UnidosFil: Eloranta, Edwin W.. University of Wisconsin; Estados UnidosFil: Fernandez, Rafael Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Hall, Samuel R.. National Center for Atmospheric Research; Estados UnidosFil: Hornbrook, Rebecca S.. National Center for Atmospheric Research; Estados UnidosFil: Pierce, R. Bradley. National Environmental Satellite, Data, and Information Service; Estados UnidosFil: Reeves, J. Michael. National Center for Atmospheric Research; Estados UnidosFil: Saiz López, Alfonso. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; EspañaFil: Ullmann, Kirk. National Center for Atmospheric Research; Estados Unido