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Polymerization of Ethylene Oxide with Alkyllithium Compounds and the Phosphazene Base “tBuP4”
Well‐defined poly(ethylene oxide)s with low polydispersities are formed in the anionic polymerization of ethylene oxide with an alkyllithium/phosphazene base initiator system. The base can be regarded as a cryptand for Li + ions. The equilibrium between complexed alkoxide ion pairs and reactive free anions is thus shi…
Electrochemistry of Conductive Polymers: XX. Early Stages of Aniline Polymerization Studied by Spectroelectrochemical and Rotating Ring Disk Electrode Techniques
Early stages of aniline oxidation have been studied employing spectroelectrochemical and rotating ring disk electrode experiments in solutions of low (2 m M ) and high (100 m M ) aniline concentrations in . Results indicate that a large amount of the tail‐to‐tail dimer, benzidine, is produced in the initial stage of a…
Characterization of the Ageing of Plasma-deposited Polymer Films: Global Analysis of X-ray Photoelectron Spectroscopy Data
A protocol for global analysis of x-ray photoelectron spectra of plasma-deposited polymer films is presented. These materials are difficult to analyse because of the multitude of different chemical groups present. The combination of different primary and secondary binding energy shifts results in relatively broad, fea…
Recent Advances in Ceramics for Dentistry
For the last ten years, the application of high-technology processes to dental ceramics allowed for the development of new materials such as heat-pressed, injection-molded, and slip-cast ceramics and glass-ceramics. The purpose of the present paper is to review advances in new materials and processes available for mak…
Why Does Halloysite Roll?—A New Model
Abstract A model is presented to explain why tubular halloysite rolls in preference to tetrahedral rotation to correct misfit of the octahedral and tetrahedral sheets. It is shown that the rolling mechanism operates as it encounters significantly less resistance from Si-Si repulsion in comparison to tetrahedral rotati…
Electrochromic Properties of Cobalt Oxide Thin Films Prepared by Chemical Vapor Deposition
Electrochromic cobalt oxide thin films were prepared by chemical vapor deposition. The source material was cobalt(II) acetylacetonate. Tricobalto tetraoxide thin films were obtained at a substrate temperature 250°C. Oxidation and reduction of the films in a 0.1 M KOH solution resulted in changes in optical absorption.…
Modification of poly(L‐lactides) by blending: mechanical and hydrolytic behavior
Abstract Two different poly( L ‐lactides) (PLLAb and PLLAa) were blended with poly(ε‐caprolactone) (PCL) and an elastic poly(ε‐caprolactone/L‐lactide) P(CL/L‐LA) copolymer to modify the mechanical properties of PLLA. Blends of both PLLAs with 20 wt.‐% of PCL were prepared. PLLAa was blended with 20 wt.‐% of P(CL/L‐LA)…
Beyond the isotropic-model approximation in the theory of thermal conductivity
By the use of an iterative method the linearized phonon-Boltzmann equation for a dielectric solid subjected to a thermal gradient is solved in the frame of three-phonon interactions. In this way it is possible to calculate the thermal conductivity of rare-gas solids starting from the pair potential and accounting for…
The Current Status of Interpenetrating Polymer Networks
An interpenetrating polymer network, IPN, is defined as a combination of two or more polymers in network form, at least one of which is polymerized and/or crosslinked in the immediate presence of the other(s). The synthesis, morphology and mechanical properties of recent works are reviewed, with special emphasis on du…
Phase II clinical evaluation of Gd-EOB-DTPA: dose, safety aspects, and pulse sequence.
PURPOSE: To investigate the efficacy of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) in the detection of focal liver lesions with respect to dose, side effects, and pulse sequence. MATERIALS AND METHODS: A randomized double-blinded trial was performed in 33 patients with focal solid liver l…
Polylactide macroporous biodegradable implants for cell transplantation. II. Preparation of polylactide foams by liquid-liquid phase separation
Potential of thermally induced phase separation as a porogen technique has been studied in an effort to produce a surgical implant suitable for cell transplantation. Emphasis has been placed on the liquid-liquid phase separation of solutions of amorphous poly DL-lactide and semicrystalline poly L-lactide in an 87/13 d…
Observed Surface Energy Effects in Confined Diblock Copolymers
By using thin layers of random copolymer, we have varied the specificity of block-wall interactions for films of diblock copolymer confined between parallel walls. For highly specific interactions (bare walls), one block component segregates to both interfaces, and the frustration due to incommensuration between film…
The immunosuppressive fungal metabolite gliotoxin specifically inhibits transcription factor NF-kappaB.
Opportunistic infections, such as aspergillosis, are among the most serious complications suffered by immunocompromised patients. Aspergillus fumigatus and other pathogenic fungi synthesize a toxic epipolythiodioxopiperazine metabolite called gliotoxin. Gliotoxin exhibits profound immunosuppressive activity in vivo. I…
Gold nanoparticles in micellar poly(styrene)‐b‐poly(ethylene oxide) films—size and interparticle distance control in monoparticulate films
Block copolymer micelles have been employed as nanosized reactors in which single gold particles were formed. Films can be produced by a process consisting of four steps. Monolayers of hexagonally assembled micelles (see Figure and this month's cover) can be prepared with rather regularly arranged, size‐controlled Au…
The excitation of UHF signals by partial discharges in GIS
The fundamental theory of the UHF method for detecting partial discharge (PD) in gas insulated substations (GIS) is presented. The effects of position, size, current amplitude and pulse shape of the PD source on the UHF signal can be predicted using this theory. Excitation of propagating electromagnetic waves by a PD…
The Polyelectrolyte Nature of F-actin and the Mechanism of Actin Bundle Formation
Polymerized (F-)actin is induced to form bundles by a number of polycations including divalent metal ions, Co(NH3)63+, and basic polypeptides. The general features of bundle formation are largely independent of the specific structure of the bundling agent used. A threshold concentration of polycation is required to fo…
Cooperative Jahn-Teller effect and electron-phonon coupling inLa1−xAxMnO3
A classical model for the lattice distortions of ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathit{A}}_{\mathit{x}}$${\mathrm{MnO}}_{3}$ is derived and, in a mean field approximation, solved. The model is based on previous work by Kanamori and involves localized Mn d electrons (which induce tetragonal dist…
Biodegradable Polymeric Materials
What can stop the mountain of discarded plastic packaging from growing? One solution to be considered is the development and use of biodegradable polymers. The advantages and drawbacks of various biodegradable plastics, water‐soluble polymers, and natural and semisynthetic polymers are outlined in tis review. The Figu…
An Electrochemical Model for Prediction of Corrosion of Mild Steel in Aqueous Carbon Dioxide Solutions
A predictive model was developed for uniform carbon dioxide (CO2) corrosion, based on modeling of individual electrochemical reactions in a water-CO2 system. The model takes into account the electrochemical reactions of hydrogen ion (H+) reduction, carbonic acid (H2CO3) reduction, direct water reduction, oxygen reduct…