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C Boes

Publications and source records attributed to C Boes.

9 recordsLinked to original sources
PubMed2003

Secondary ion and laser ablation mass spectrometry for the quantitative characterization of styrene-butadiene copolymers.

Styrene-butadiene copolymers were analyzed by static secondary ion mass spectrometry (S-SIMS) and laser ablation Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICRMS) to obtain quantitative information based on specific ions. Silver deposition was performed on polystyrene, butadiene rubber and styrene-butadiene rubber. Under these experimental conditions, new secondary ions were detected, in particular silver-cationized butadiene [M(butadiene) - Ag](+) and styrene [M(styrene) - Ag](+) monomers. In contrast, LA-FTICRMS experiments did not require pretreatment. At high laser power density, UV photons (193, 266 and 355 nm) allowed the detection of styrene and butadiene monomers at m/z 104 and 54, respectively. The use of the observed ions by SIMS or LA-FTICRMS ensures that quantitative information on the relative distribution of each monomer is obtained. However, the silver coating thickness in the SIMS experiment seems to have an important influence on the quantitative information obtained. For LA-FTICRMS experiments, the best results are obtained at a wavelength of 355 nm.

Journal Article↗
PubMed2000

[Reliability and validity of the Braden Scale for predicting pressure sore risk].

For more accurate and objective pressure sore risk assessment various risk assessment tools were developed mainly in the USA and Great Britain. The Braden Scale for Predicting Pressure Sore Risk is one such example. By means of a literature analysis of German and English texts referring to the Braden Scale the scientific control criteria reliability and validity will be traced and consequences for application of the scale in Germany will be demonstrated. Analysis of 4 reliability studies shows an exclusive focus on interrater reliability. Further, even though examination of 19 validity studies occurs in many different settings, such examination is limited to the criteria sensitivity and specificity (accuracy). The range of sensitivity and specificity level is 35-100%. The recommended cut off points rank in the field of 10 to 19 points. The studies prove to be not comparable with each other. Furthermore, distortions in these studies can be found which affect accuracy of the scale. The results of the here presented analysis show an insufficient proof for reliability and validity in the American studies. In Germany, the Braden scale has not yet been tested under scientific criteria. Such testing is needed before using the scale in different German settings. During the course of such testing, construction and study procedures of the American studies can be used as a basis as can the problems be identified in the analysis presented below.

Forecasting↗
PubMed1994

Central nervous system aspergillosis. Analysis of 26 patients.

The clinical presentation, risk factors, laboratory data, and neuroimaging and neuropathological findings in 26 patients with autopsy proved central nervous system (CNS) aspergillosis are reviewed. Eleven patients had hematological malignancies (8 underwent bone marrow transplantation), 8 patients underwent liver transplantation, and 3 patients had acquired immunodeficiency syndrome. Four had illnesses resulting in immunosuppression (systemic lupus erythematosus, infected aortic graft, neuroblastoma, and fulminant hepatic failure). The most common presenting clinical symptoms of CNS aspergillosis were fever and a strokelike syndrome. Risk factors for developing CNS aspergillosis included neutropenia, immunosuppressive therapy, low CD4 counts, and retransplantation. Spinal fluid findings were nondiagnostic. Computed tomograms and magnetic resonance scans of the head showed low-density lesions or hemorrhagic infarctions. Most aspergillosis cases occurred in the setting of widely disseminated disease commonly arising from the lung. Pathologically, multiple areas of necrosis throughout the brain were seen. Aspergillus invasion of blood vessel walls was seen microscopically. Amphotericin B with or without flucytosine was not effective treatment.

Adolescent↗
PubMed1985

[Possible common partial antigens in human Ig allotype structure and ubiquitous bacteria, studied with the example of Escherichia coli].

As can be learned from the literature, bovine serum may contain antibodies directed against human immunoglobulin allotypes. This gave rise to the question of what the origin of those antibodies is. We tested bacteria (E. coli) by means of the haemagglutination inhibition assay, which is used to type either Gm or Km factors. Anti-G1m(2) and anti-G3m(10)-specific antibodies were inhibited by the bacteria in a clear-cut manner, as was anti-Km(1), albeit less significantly. In contrast, the bacteria tested almost totally failed to inhibit anti-G3m(21) serum. The results lead to the assumption that E. coli may carry both Gm- and Km-like antigenic structures, which are presumably the antigenic material leading to immunization of cattle. Furthermore, new attention is drawn to a mechanism for immunization which is discussed regarding the genesis of either AB0 isoagglutinins in man or other "naturally occurring" antibodies.

Antibodies↗