ABSTRACT
Ferrocene and its decamethyl derivative [Cp*2Fe] are the most common standards for nonaqueous electrochemical investigations because of their well-defined and only mildly solvent-dependent reversible Fe(II)/Fe(III) redox couple. Higher oxidation states have only rarely been studied. We report the isolation and crystallographic and spectroscopic characterization of surprisingly stable Fe(IV) salts of the [Cp*2Fe](2+) dication, produced by oxidation of [Cp*2Fe] with AsF5, SbF5, or ReF6 in neat sulfur dioxide as well as [XeF](Sb2F11) in neat hydrogen fluoride. The Sb2F11(-) salt exhibits a metallocene with the expected mutually parallel arrangements of the Cp* rings, whereas the As2F11(-), AsF6(-), SbF6(-), and ReF6(-) salts manifest tilt angles ranging from 4° to 17°. Both (57)Fe Mössbauer spectroscopy and superconducting quantum interference device magnetization studies reveal identical d-orbital splitting with an S = 1, (3)E ground state based on the 3d electronic configuration e2g (3)a1g (1) of all [Cp*2Fe](2+) salts.
ABSTRACT
A low-valent trinuclear iron complex with an unusual linear Fe(I)-Fe(II)-Fe(I) unit is presented. It is accessed in a rational approach using a salt metathesis reaction between a new anionic Fe(I) containing heterocycle and FeCl2. Its electronic structure was studied by single crystal XRD analysis, EPR and Mössbauer spectroscopy, and magnetic susceptibility measurements.
Subject(s)
Bacterial Infections/microbiology , Disease Outbreaks/statistics & numerical data , Gastroenteritis/epidemiology , Gastroenteritis/microbiology , Risk Assessment/methods , Water Pollution/statistics & numerical data , Water Supply/statistics & numerical data , Denmark/epidemiology , Humans , Incidence , Population Surveillance , Risk Factors , Water MicrobiologyABSTRACT
BACKGROUND: Patients with end-stage renal disease display enhanced genomic damage. We investigated the relation between genomic damage and different treatment modalities. METHODS: In a longitudinal study two groups of patients were analyzed in monthly intervals. We assessed the initiation of hemodialysis in 5 conservatively treated patients, and a switch from hemodialysis to hemodiafiltration in 7 patients. DNA damage was investigated in peripheral blood lymphocytes by micronucleus frequency and by comet assay analysis. With regard to potential genotoxicity of advanced glycation end products (AGEs), levels of imidazolone A and AGE-associated fluorescence (AGE-FL) were determined. RESULTS: The initiation of hemodialysis did not alter the genomic damage. In patients who switched from hemodialysis to hemodiafiltration, a small but significant reduction in the comet assay but not in the micronucleus frequency was observed. Elevated plasma levels of imidazolone A and AGE-FL were not influenced by the treatment modalities. CONCLUSION: In our small patient group no major reduction of the elevated genomic damage could be reached. Disease factors not influenced by altered dialysis modalities may have contributed considerably in our patient group. The persisting high levels of DNA damage suggest a need for further improvement. Inhibiting AGE formation may be one promising way for the future.
Subject(s)
DNA Damage , Hemodiafiltration , Kidney Failure, Chronic/genetics , Kidney Failure, Chronic/therapy , Renal Dialysis , Aged , Comet Assay , Genome, Human , Glycation End Products, Advanced/blood , Humans , Imidazoles/blood , Longitudinal Studies , Lymphocytes/physiology , Male , Micronuclei, Chromosome-Defective , Middle Aged , Treatment Outcome , Uremia/genetics , Uremia/therapyABSTRACT
An increased risk of cancer of the upper aerodigestive tract has been demonstrated among the members of the Danish Brewery Workers Union. To determine the role of tobacco, beer and strong liquors in the development of these cancers, a case-control study was conducted among those brewery workers who during the years 1943-1972 developed cancer of the pharynx (excluding nasopharynx), larynx, or esophagus. Controls were chosen among brewery workers who did not develop these cancers. Data concerning individual drinking and smoking habits were collected retrospectively from hospital records and by means of a mailed, self-administered questionnaire for patients or their relatives. An analysis based on the combined set of information from the two sources, showed an increased relative risk of developing an upper aerodigestive cancer, with increasing daily tobacco consumption. Likewise, we found an increasing relative risk with increasing daily alcohol consumption, statistically significant for oesophagus cancer and for all three cancer types as a whole. When looking at daily beer consumption alone, the same increased risk was found, but was only statistically significant for oesophagus cancer. No evidence of any particularly heavy consumption of strong alcoholic beverages was seen amongst the brewery workers as a whole or amongst the cases. Thus, the study supports the hypothesis that heavy beer intake may be a risk factor in the development of upper aerodigestive cancer.
