Search results for "Scanning"
showing 10 items of 1808 documents
Colonization pattern of primary tomato roots by Pseudomonas fluorescens A6RI characterized by dilution plating, flow cytometry, fluorescence, confoca…
2004
Early colonization of primary tomato roots, grown in vitro, by Pseudomonas fluorescens A6RI, introduced by seed bacterization, was monitored for 7 days in three different root zones (zone A, apex+elongation+young hairy zone; zone B, hairy zone; zone C, old hairy zone+collar). Bacterial quantification was assessed by enumeration of (i) colony forming units (cfu) after dilution plating and of (ii) total bacterial cells by flow cytometry. Bacterial distribution and organization in the root zones were analyzed by fluorescence, confocal and scanning electron microscopy. For all sampling dates and zones, the densities of total bacterial cells were significantly higher than those of the cfu. The k…
Survival Strategy of Erwinia amylovora against Copper: Induction of the Viable-but-Nonculturable State
2006
Copper compounds, widely used to control plant-pathogenic bacteria, have traditionally been employed against fire blight, caused by Erwinia amylovora. However, recent studies have shown that some phytopathogenic bacteria enter into the viable-but-nonculturable (VBNC) state in the presence of copper. To determine whether copper kills E. amylovora or induces the VBNC state, a mineral medium without copper or supplemented with 0.005, 0.01, or 0.05 mM Cu2+ was inoculated with 107 CFU/ml of this bacterium and monitored over 9 months. Total and viable cell counts were determined by epifluorescence microscopy using the LIVE/DEAD kit and by flow cytometry with 5-cyano-2,3-ditolyl tetrazolium chlori…
The fine structural organization of sternal glands of pseudergates and workers in termites (Isoptera): a comparative survey
2008
1873-5495 (Electronic) Comparative Study Journal Article; Thirty-nine species belonging to different families of termites are studied to give a comprehensive view of the evolution of the sternal glands. Several modifications occurring at cuticular and cytological levels are described in neuter castes. The outer epicuticle is always pierced by epicuticular pores. In advanced termites the epicuticular filaments greatly increase in number and length creating a thick layer. The pore canals gradually enlarge while the cuticle changes into a lattice structure lining an extracellular space in which the secretion is stored. Two classes of cells are present in basal termites (Mastotermitidae, Hodote…
Comparison of Different Processing Methods to Prepare Poly(lactid acid)–Hydrotalcite Composites
2013
The effect of the compounding method on the morphology and on the properties of poly(lactic acid) (PLA)-hydrotalcite (HT) composites was studied. Moreover, the influence of two different kinds of HT - organically modified (OM-HT) and unmodified (U-HT) - and their concentration was evaluated. The composites were prepared using either a single screw extruder (SSE), a counter rotating twin-screw compounder (TSC) or a corotating twin-screw extruder (TSE). The prepared materials were characterized by scanning electron microscopy, gel permeation chromatography (GPC) analysis, mechanical and rheological measurements. The results indicated that the best morphology, i.e., particles dimension and dis…
PyDSC: a simple tool to treat differential scanning calorimetry data
2020
AbstractHerein, we describe an open-source, Python-based, script to treat the output of differential scanning calorimetry (DSC) experiments, called pyDSC, available free of charge for download at https://github.com/leonardo-chiappisi/pyDSC under a GNU General Public License v3.0. The main aim of this program is to provide the community with a simple program to analyze raw DSC data. Key features include the correction from spurious signals, and, most importantly, the baseline is computed with a robust, physically consistent approach. We also show that the baseline correction routine implemented in the script is significantly more reproducible than different standard ones proposed by propriet…
On the use of PET-LCP copolymers as compatibilizers for PET/LCP blends
1996
Copolyesters of poly[ethylene terephthalate) (PET) with a liquid crystalline polymer (LCP), SBH 1:1:2, have been synthesized by the polycondensation, carried out in the melt at temperatures up to 300 degrees C of sebacic acid (S), 4,4'-dihydroxybiphenyl (B), and 4-hydroxybenzoic acid (H) in the presence of PET. The PET-SBH copolyesters have been characterized by differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, etc., and the relationships between properties and preparation conditions are discussed. The copolyesters show a biphasic nature, which is more evident for the products synthesized with a thermal profile comprising relatively lower temperatures (220-…
Improving thermoelectric performance of TiNiSn by mixing MnNiSb in the half-Heusler structure
2016
The thermoelectric properties of n type semiconductor, TiNiSn is optimized by partial substitution with metallic, MnNiSb in the half Heusler structure. Herein, we study the transport properties and intrinsic phase separation in the system. The Ti1-xMnxNiSn1-xSbx alloys were prepared by arc-melting and were annealed at temperatures obtained from differential thermal analysis and differential scanning calorimetry results. The phases were characterized using powder X-ray diffraction patterns, energy dispersive X-ray spectroscopy, and differential scanning calorimetry. After annealing the majority phase was TiNiSn with some Ni rich sites and the minority phases was majorly Ti6Sn5, Sn, and MnSn2…
Probing Physical Properties of Confined Fluids within Individual Nanobubbles
2008
Spatially resolved electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) has been used to investigate as fluidic phase in nanoubbles embedded in a metallic Pd90Pt10 matrix. Using the 1s->2p excitation of the He atoms, maps of the He distribution, in particular of its density an pressure in bubbles of different diameter have been realized, thus providing an indication of the involved bubble formation mechanism. However, the short-range Pauli repulsion mechanism between electrons on neighboring atoms seems insufficient to interpret minute variations of the local local measurements performed at the interface between the metal and the He bubble. Simul…
Quantum Well States in Two-Dimensional Gold Clusters on MgO Thin Films
2008
The electronic structure of ultra-small Au clusters on thin MgO/Ag(001) films has been analyzed by scanning tunneling spectroscopy and density functional theory. The clusters exhibit two-dimensional (2D) quantum well states, whose shapes resemble the eigen-states of a 2D electron gas confined in a parabolic potential. From the symmetries of the HOMO and LUMO of a particular cluster, its electron filling and charge state is determined. In accordance to a DFT Bader-charge analysis, aggregates containing up to twenty atoms accumulate one to four extra electrons due to a charge transfer from the MgO/Ag interface. The HOMO - LUMO gap is found to close for clusters containing between 70 and 100 a…
Structural and Magnetic Properties of Co-Fe Binary Alloy Monolayers on W(110)
2003
We present an experimental investigation of ${\mathrm{C}\mathrm{o}}_{x}{\mathrm{F}\mathrm{e}}_{1\ensuremath{-}x}$ monolayers grown on flat and stepped W(110) surfaces. Atomically resolved scanning tunneling microscopy and low energy electron diffraction reveal continuous miscibility and pseudomorphic growth of Co and Fe for $0\ensuremath{\le}xl0.6$. We observe short range ordered ${\mathrm{C}\mathrm{o}\mathrm{F}\mathrm{e}}_{3}$-$p(2\ifmmode\times\else\texttimes\fi{}2)$ and CoFe-$c(2\ifmmode\times\else\texttimes\fi{}2)$ structures in the pseudomorphic monolayer. High Co concentrations lead to a phase separation. The Curie temperature and the ferromagnetic Kerr signal at low temperatures decr…