Münzmetallkomplexe mit sekundären Bindungen

In der Dissertation zum Thema 'Münzmetallkomplexe mit sekundären Bindungen' wird der Einfluß von Wasserstoffbrücken, aurophilen Wechselwirkungen und weich-weich-Wechselwirkungen auf die Struktur und Stabilität von Gold(I)- und Silber(I)-Komplexen untersucht. Der Einfluß der sekundären Wechselwirkungen auf die Struktur der neu synthetisierten Komplexe wurde mit Hilfe der aus Einkristall-Röntgenstrukturanalysen erhaltenen Daten dargestellt. Die durch Wasserstoffbrückenbindungen entstandenen Motive wurden mit Hilfe von Graphensätzen beschrieben. Im Hauptteil der Dissertation werden die Eigenschaften in Lösung und im Festkörper von Gold(I)-Amin-Komplexen mit Chloroliganden bzw. Chloridanion diskutiert. Als Liganden wurden primäre und sekundäre Amine sowie Methylpyridine eingesetzt. Mit tertiären Aminen und Pyridinen mit elektronenziehenden Substituenten wurden keine stabilen Komplexe erhalten. Desweiteren wird die Änderung der Struktur bei Austausch des Chloroliganden gegen Pentafluorphenyl, Hexafluorantimonat oder Di(organosulfonyl)amide untersucht. In einem weiteren Kapitel werden Gold(I)- und Silber(I)-Komplexe mit Diphenylphosphin-(diphenylphosphinselenid)methan als Ligand diskutiert.The PhD thesis 'Coinage metals with secondary bonds' deals with the influence of hydrogen bonds, aurophilic and soft-soft interactions on the structure and stability of gold(I) and silver(I) complexes. The influence of secondary bonds on the structure of the novel complexes was demonstrated by data obtained by single-crystal X-ray analysis. The hydrogen bonding motifs were classified by graph sets. Within the main part of the PhD thesis, the properties of gold(I) amine complexes with chloro ligands or chloride as anion in solution and the solid state are discussed. Primary and secondary amines and methylpyridines were used as ligands. Tertiary amines and pyridines with electron-withdrawing substituents did not form stable complexes. The difference in structure when changing the anion from chloride to pentafluorphenyl, hexafluoroantimonate or di(organosulfonyl)amides was also discussed. A further part of the PhD thesis deals with gold(I) and silver(I) complexes with the ligand diphenylphosphine(diphenylphosphineselenide)methane

The Advocate

Headlines Include: Laurels For Feerick: An Alumnus To Remember; Crime at Fordham; Who\u27s Next?, Film at 11https://ir.lawnet.fordham.edu/student_the_advocate/1007/thumbnail.jp

One Group of Genetically Similar Listeria monocytogenes Strains Frequently Dominates and Persists in Several Fish Slaughter- and Smokehouses

Contamination of foods with the human pathogen Listeria monocytogenes may occur during processing, and the purpose of this study was to determine whether genetically similar strains colonize different processing plants or whether specific persistent strains are unique to each processing plant. We hypothesized that specific L. monocytogenes strains may be better adapted to specific environmental niches in the processing environment. L. monocytogenes contamination patterns were identified by the collection of 686 and 267 samples from the processing environments: raw fish and products of four fish smokehouses and four fish slaughterhouses, respectively. Samples were collected both during production and after cleaning and disinfection. Typically, these samplings were separated by 1 to 3 months. Sampling sites were targeted toward areas likely to harbor the bacterium. L. monocytogenes was isolated from 213 samples, and one strain from each positive sample was typed by RAPD (random amplified polymorphic DNA) analysis with four different primers. The 213 strains were divided into 37 RAPD types. One RAPD type was predominant; 86 of 213 strains belonged to this type. This type was found in three smokehouses and two slaughterhouses and was predominant in three of these plants. A subset of 35 strains was also analyzed by amplified fragment length polymorphism typing, which confirmed the genetic similarity of the groups. Moreover, strains of the dominant RAPD type were indistinguishable from strains isolated frequently from smoked fish products 10 years ago. One smokehouse was surveyed for a year and a half, and the dominant RAPD type persisted throughout the survey period and accounted for 94 of 118 isolates. Our study indicates that strains of L. monocytogenes that are genetically very closely related may be especially adapted to colonizing the processing equipment or especially resistant to cleaning and disinfection

Elucidation of Listeria monocytogenes Contamination Routes in Cold-Smoked Salmon Processing Plants Detected by DNA-Based Typing Methods

The contamination routes of Listeria monocytogenes in cold-smoked salmon processing plants were investigated by analyzing 3,585 samples from products (produced in 1995, 1996, 1998, and 1999) and processing environments (samples obtained in 1998 and 1999) of two Danish smokehouses. The level of product contamination in plant I varied from 31 to 85%, and no L. monocytogenes was found on raw fish (30 fish were sampled). In plant II, the levels of both raw fish and product contamination varied from 0 to 25% (16 of 185 raw fish samples and 59 of 1,000 product samples were positive for L. monocytogenes). A total of 429 strains of L. monocytogenes were subsequently compared by random amplified polymorphic DNA (RAPD) profiling, and 55 different RAPD types were found. The RAPD types detected on the products were identical to types found on the processing equipment and in the processing environment, suggesting that contamination of the final product (cold-smoked salmon) in both plants (but primarily in plant I) was due to contamination during processing rather than to contamination from raw fish. However, the possibility that raw fish was an important source of contamination of the processing equipment and environment could not be excluded. Contamination of the product occurred in specific areas (the brining and slicing areas). In plant I, the same RAPD type (RAPD type 12) was found over a 4-year period, indicating that an established in-house flora persisted and was not eliminated by routine hygienic procedures. In plant II, where the prevalence of L. monocytogenes was much lower, no RAPD type persisted over long periods of time, and several different L. monocytogenes RAPD types were isolated. This indicates that persistent strains may be avoided by rigorous cleaning and sanitation; however, due to the ubiquitous nature of the organism, sporadic contamination occurred. A subset of strains was also typed by using pulsed-field gel electrophoresis and amplified fragment length polymorphism profiling, and these methods confirmed the type division obtained by RAPD profiling