Correction to: Higher strong order methods for linear Itô SDEs on matrix Lie groups

BIT Numerical Mathematics -     

Influence of plasma treatment on the molar mass of poly(ethylene terephthalate) investigated by different chromatographic and spectroscopic methods

The influence of different types of low and atmospheric pressure plasma on poly(ethylene terephthalate) (PET) has been studied in terms of changes in molar mass and molar mass distribution. Apart from a variation of plasma gases (oxygen, helium) different types of plasma (microwave, radio frequency, corona discharge) were used for the plasma surface modification. The changes in molar mass and types of functional end groups of lower molar mass products were investigated by means of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOFMS), whereas the high-molar mass fraction was analyzed by means of size-exclusion chromatography (SEC). The formation of crosslinked products during exposure to a helium plasma, which emits preponderately energy-rich and intense ultraviolet radiation, was proved by means of thermal field-flow fractionation (ThFFF). This method combined with a multiangle laser light scattering (MALLS) detector allows detection of weakly crosslinked polymers and microgels. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1639–1648, 1998     

Heteroatomfunktionalisierte Methylgold-Komplexe: Synthese und Struktur von Chlormethyl(triphenylphosphin)- und Phenylthiomethyl(trimethylphosphin)gold

Heteroatom-functionalized Methylgold Complexes: Synthesis and Structure of Chloromethyl(triphenylphosphine)- and Phenylthiomethyl(trimethylphosphine)gold [AuCl(PPh₃)] reacts with Mg(CH₂Cl)Cl, prepared in situ from CH₂ClI and iPrMgCl, in ether at –65 °C to give [Au(CH₂Cl)(PPh₃)] ( 1 a ). 1 a reacts with LiI, NaOMe and PPh₃ to give [Au(CH₂I)(PPh₃)] ( 2 ), [Au(CH₂OMe)(PPh₃)] ( 3 ) and [Au(CH₂PPh₃)(PPh₃)]Cl ( 4 ), respectively. 2 decomposes rapidly at room temperature, yielding ethylene and [AuI(PPh₃)]. The reaction of [AuCl(PMe₃)] with LiCH₂SPh in THF affords [Au(CH₂SPh)(PMe₃)] ( 5 ). The chloromethyl and the phenylthiomethyl complex 1 a and 5 were isolated and characterized by NMR (¹H, ¹³C, ³¹P) spectroscopy as well as by single-crystal X-ray structure analysis. In the solid state discrete molecules of 1 a and 5 are found with linear C–Au–P units [C–Au–P 179,8(4)° ( 1 a ), 179,1(1)° ( 5 )]. The angle Au–C–Cl (115,4(6)°) in 1 a is slightly greater than the tetrahedral angle.     

Produktion von β-Lactamantibiotika durch Mikroorganismen

β-lactam antibiotics are commercially and clinically important compounds that are produced by bacteria as well as by filamentous fungi. There is a great interest not only to increase the yield of microbial antibiotic production but also to generate new and highly effective antibiotics. It may be foreseen that this aim is reached by the use of in vitro recombinant technology. The biochemical as well as the physiological data which seem to be important for the understanding of β-lactam biosynthesis is filamentous fungi are summarised. In addition, recent technical advances are mentioned which become available through molecular biology. Examples are given to demonstrate the feasability of DNA recombinant technology for biotcchnical applications by introducing novel biosynthetic pathways into fungal β-lactam producers.     

THERMOCHROMIC EFFECTS OF LEUCO DYES STUDIED IN POLYPROPYLENE

A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-（1-n-butyl-2-methyl-3-indolyl）-phthalide as dyes and l-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.     

Crystallization behavior of polycaprolactone/babassu compounds

Journal of Thermal Analysis and Calorimetry - Polycaprolactone/babassu compounds were prepared in a laboratory internal mixer, their melt crystallization behavior was investigated using a...     

Sources of primary production to Arctic bivalves identified using amino acid stable carbon isotope fingerprinting*

ABSTRACT

Benthic invertebrates are a crucial trophic link in Arctic marine food webs. However, estimates of the contribution of different primary production sources sustaining these organisms are not well characterised. We measured the stable carbon isotope values (δ¹³C) of essential amino acids (EAAs) in muscle tissue from two common bivalve genera (Macoma spp. and Astarte spp.) collected in Hanna Shoal in the northeastern Chukchi Sea. Mixing models comparing the δ¹³C_EAA fingerprints of the bivalves to a suite of primary production endmembers revealed relatively high contributions of EAAs from phytoplankton and bacteria in both species. We also examined whether δ¹³C_EAA fingerprints could be produced from the EAAs preserved in bivalve shells, which could allow primary production sources to be estimated from ancient bivalve shells. The δ¹³C_EAA fingerprints from a suite of paired modern bivalve shells and muscle from Macoma calcarea from across the Chukchi Sea revealed a correspondence between the estimates of the dominant primary production source of EAAs derived from analyses of these two tissue types. Our findings indicate that δ¹³C_EAA fingerprinting of marine bivalves can be used to examine dominant organic matter sources in the Arctic marine benthos in recent years as well as in deeper time.