Switching of Magnons by Electric and Magnetic Fields in Multiferroic Borates.

Electric manipulation of magnetic properties is a key problem of materials research. To fulfill the requirements of modern electronics, these processes must be shifted to high frequencies. In multiferroic materials, this may be achieved by electric and magnetic control of their fundamental excitations. Here we identify magnetic vibrations in multiferroic iron borates that are simultaneously sensitive to external electric and magnetic fields. Nearly 100% modulation of the terahertz radiation in an external field is demonstrated for SmFe_{3}(BO_{3})_{4}. High sensitivity can be explained by a modification of the spin orientation that controls the excitation conditions in multiferroic borates. These experiments demonstrate the possibility to alter terahertz magnetic properties of materials independently by external electric and magnetic fields.

Profound haemodilution during normothermic cardiopulmonary bypass influences neither gastrointestinal permeability nor cytokine release in coronary artery bypass graft surgery.

BACKGROUND: Cardiopulmonary bypass (CPB) impairs intestinal barrier function and induces systemic inflammation after cardiac surgery. The objective of this study was to evaluate the effect of profound haemodilution (haematocrit 19-21%) during normothermic CPB on gastrointestinal permeability and cytokine release in comparison with a standard haemodilution (haematocrit 24-26%). METHODS: This was a prospective, controlled, randomized pilot trial of 60 patients without gastrointestinal disease undergoing normothermic CPB (35.5-36 degrees C) for coronary artery bypass graft surgery. Gastrointestinal permeability was measured by the triple-sugar technique (sucrose, lactulose, and mannitol excretion in urine) before and after CPB. Interleukin (IL)-6, IL-10, and tumour necrosis factor alpha (TNFalpha) were quantified using enzyme-linked immunosorbent assays. RESULTS: Data from 59 patients (19-21% haematocrit, n=28; 24-26% haematocrit, n=31) were analysed. Data on gastrointestinal permeability were available for 47 patients (19-21% haematocrit, n=23; 24-26% haematocrit, n=24), blood samples for cytokine analysis from 59 patients. Mannitol excretion was normal before and after surgery without significant differences between the groups (after operation: 5.4% vs 2.9%, P=0.193). Lactulose and sucrose excretion was within a normal range before surgery and increased afterwards without differences between the groups. IL-6, IL-10, and TNFalpha were elevated after surgery, but there was no difference between the groups [IL-6 (P=0.78), IL-10 (P=0.74), and TNFalpha (P=0.67)]. CONCLUSIONS: Profound haemodilution during normothermic CPB brought about significant changes neither in intestinal permeability nor in cytokine release. It may be concluded that a haematocrit of 19-21% during normothermic CPB does not impair intestinal barrier function and cytokine response in patients without gastrointestinal comorbidity.

Colitis caused by Clostridium difficile: a review.

Recent evidence has incriminated a toxin-producing anaerobe, Clostridium difficile, as the causative agent of pseudomembranous colitis, an acute inflammatory bowel disease that generally occurs in association with antimicrobial therapy. A wide variety of antimicrobial agents appear to promote C. difficile infection and thereby precipitate colitis. Although the exact pathogenetic mechanisms are not known, several hypotheses, related to the ability of antibiotics to suppress competing bacteria and alter bacterial adhesion to intestinal mucosa, are explored in this review. Laboratory participation in the diagnosis of pseudomembranous colitis caused by C. difficile involves culture and toxin assay. Isolation of C. difficile from feces is facilitated by the use of recently developed selective media. Vancomycin is recommended for treatment of pseudomembranous colitis when removal of the offending antimicrobial agent does not result in clinical improvement.

Evaluation of a modified dye pour-plate auxanographic method for the rapid identification of clinically significant yeasts. Comparison with two commercial systems.

A modified dye pour-plate auxanographic (DPPA) method for the presumptive identification of medically important yeasts was evaluated, in a comparative study with a conventional procedure, the API 20C clinical yeast system (Analytab Products Inc.), and the Uni-Yeast-Tek (UYT) system. The 174 coded clinical isolates were members of the genera Candida, Cryptococcus, Rhodotorula, Saccharomyces, Torulopsis, and Trichosporon. The identification accuracies with DPPA, API, and UYT were 95%, 93%, and 99% respectively. DPPA and API required more time to inoculate but gave rapid identification profiles. UYT was simple to inoculate and both UYT and DPPA were easy to read. Cost analysis of the three rapid methods demonstrated DPPA to be the most economical making it a feasible alternative for small clinical laboratories as well as large laboratories possessing the facilities to make their own media.