On the identity of Pleurosigma angulatum (Bacillariophyta) and related species
(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.
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Systematic generation of all nonequivalent closest-packed stacking sequences of length N using group theory
An algorithm has been developed that generates all of the nonequivalent closest-packed stacking sequences of length N. There are 2(N) + 2(-1)(N) different labels for closest-packed stacking sequences of length N using the standard A, B, C notation. These labels are generated using an ordered binary tree. As different…
Long chain alkyl amine templated synthesis of a mesostructured lamellar vanadium phosphate phase
n-Hexadecylamine (HDA) has been used as a template to synthesize a mesolamellar vanadium phosphate (VPO) phase. FTIR studies indicate covalent interaction of the amine head with the vanadyl groups of the VPO matrix, in contrast to the other reported syntheses of mesostructured VPO phases which involve ionic interactio…
Constant loss in Brillouin spectra of polymers
Abstract The polarized (VV) and depolarized (VH) light scattering spectra of polyisobutylene, poly(methyl methacrylate), and glycerol were measured in the gigahertz frequency range at temperatures below and above the glass transition. Both VV and VH spectra exhibit a significant constant loss contribution that appears…
Liposomes in Drug Delivery
Liposomes or (phospho)lipid vesicles are self-assembled colloidal particles that occur in nature or can be prepared artificially. In the beginning, liposomes were used to study biological membranes, while several practical applications, most notably in drug delivery, emerged in the 1970s. After three decades of researc…
Characterization of the Spontaneously Forming Hydrogels Composed of Water-Soluble Phospholipid Polymers
Spontaneously forming hydrogels composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers, poly(MPC-co-methacrylic acid) (PMA), and poly(MPC-co-n-butyl methacrylate) (PMB) were examined. The MPC copolymer hydrogel was observed to have a spontaneous gelation property. To determine the properties of the hydr…
Inorganic structures of life
Abstract From the nano-world of rusty proteins and magnetic compasses in bacteria to the macroscopic structures of oyster shells, corals, ivory, bone and enamel, biology has evolved a new type of chemistry that brings together the synthesis and construction of hard and soft matter for the design of functionalized inor…
Effects of Two Ionic Groups in an Ionic Repeat Unit on the Properties of Styrene Ionomers
The properties of poly(styrene- co -itaconate) ionomers were studied dynamic mechanically. It was observed that ionic moduli increased as ion content increased and that the increased ionic modulus values were comparable to those of well-clustered polystyrene ionomers. It was also found that only a very weak cluster lo…
Superlattice formation in the lithiated vanadium oxide phases Li0.67V6O13 and LiV6O13
Two new lithiated phases of V(6)O(13) were formed by carefully tuning the temperature of electrochemical lithiation in a "coffee-bag" type Li-ion battery at 2.78 V versus Li/Li(+). These were studied by single-crystal X-ray diffraction. A phase with the composition Li(2/3)V(6)O(13) was obtained at 308 K with a unit ce…
Photocontrol of Dynamic Phase Transition in the Charge-Density Wave MaterialK0.3MoO3
A photoinduced effect has been studied in the quasi-one-dimensional conductor K(0.3)MoO(3). A weak photoexcitation of the sample can drastically affect the dynamic phase transition of the charge-density wave (CDW) motion from slide to creep. The origin of the photoeffect is attributed to a local destruction of the CDW…
Preparation of aromatic polyimides highly soluble in conventional solvents
Abstract Several highly soluble polyimides were synthesized from various aromatic tetracarboxylic dianhydrides and an aromatic diamine containing tert ‐butyl pendent groups [4,4′‐methylenebis(2‐ tert ‐butylaniline)]. All the polyimides showed excellent solubility in common solvents such as chloroform, tetrahydrofuran,…
Use of software to search for higher symmetry: space group C2
From a search of the October 2000 release of the Cambridge Structural Database we find coordinate data for approximately 1500 entries under space group No. 5: C2 or, occasionally, A2, I2 or B112. Software designed to detect cases of missed higher symmetry identified 144 entries for detailed inspection. Of these, 50 sh…
Five-dimensional structure refinement of natural melilite, (Ca1.89Sr0.01Na0.08K0.02)(Mg0.92Al0.08)(Si1.98Al0.02)O7
The structure of a crystal of natural melilite from San Venanzo, Umbria (Italy) of the general formula X(2)T1(T2)(2)O(7), where X = Ca(0.945)Sr(0.005)Na(0.04)K(0.01), T1 = Mg(0.92)Al(0.08) and T2 = Si(0.99)Al(0.01), has been solved and refined as an incommensurate structure in five-dimensional superspace. The structur…
Characterization of Microbial Polythioesters: Physical Properties of Novel Copolymers Synthesized by Ralstonia eutropha
Various samples of polythioesters with different contents of 3-mercaptopropionic acid (3MP) or 3-mercaptobutyric acid (3MB) as one comonomer and with 3-hydroxybutyric acid (3HB) as the second constituent were produced by cultivating cells of Ralstonia eutropha strain H16 in mineral salts medium containing 3MP or 3MB p…
Potassium intercalated graphyne
Graphyne intercalation compounds are expected to function as layered organic conductors and as storage of atoms and molecules, because graphyne as a host material is highly stable and has large voids. We have performed optimization of the geometry and calculation of the electronic structures for five hypothetical stac…
Interacting fermions in self-similar potentials
We consider interacting spinless fermions in one dimension embedded in self-similar quasiperiodic potentials. We examine generalizations of the Fibonacci potential known as precious mean potentials. Using a bosonization technique and a renormalization group analysis, we study the low-energy physics of the system. We s…
Silk, Mohair, Cashmere and Other Luxury Fibres
Silk Mohair Cashmere, camelhair and other hair fibres. Appendices: International trade rules for raw silk and other products of silk Spider silk Composition of mohair fibres and of amino acids Mohair yarn spinning and properties Mohair fibre and fabric properties Mohair dyeing and finishing Mohair product list Rules f…
Formation of Short Chain Length/Medium Chain Length Polyhydroxyalkanoate Copolymers by Fatty Acid β-Oxidation Inhibited Ralstonia eutropha
Ralstonia eutropha has been considered as a bacterium, incorporating hydroxyalkanoates of less than six carbons only into polyhydroxyalkanoates (PHAs). Cells of the wild type cultivated with sodium octanoate as the carbon source in the presence of the fatty acid beta-oxidation inhibitor sodium acrylate synthesized PHA…
Kinetics, Mechanism, and Spectroscopy of the Reversible Binding of Nitric Oxide to Aquated Iron(II). An Undergraduate Text Book Reaction Revisited
A detailed kinetic and mechanistic analysis of the classical "brown-ring" reaction of [Fe(H(2)O)(6)](2+) with NO was performed using stopped-flow and laser flash photolysis techniques at ambient and high pressure. The kinetic parameters for the "on" and "off" reactions at 25 degrees C were found to be k(on) = 1.42 x 1…
Polarization relaxation kinetics and 180° domain wall dynamics in ferroelectric thin films
The time-dependent relaxation of remanant polarization in epitaxial lead zirconate titanate $[{\mathrm{P}\mathrm{b}(\mathrm{Z}\mathrm{r}}_{0.2}{\mathrm{Ti}}_{0.8}{)\mathrm{O}}_{3},\mathrm{P}\mathrm{Z}\mathrm{T}]$ ferroelectric thin films, containing a uniform two-dimensional grid of 90\ifmmode^\circ\else\textdegree\fi…