An analysis of interleukin-8, interleukin-6 and C-reactive protein serum concentrations to predict fever, gram-negative bacteremia and complicated infection in neutropenic cancer patients

A prospective study was performed to assess the potential value of interleukin (IL)-8, IL-6, and C-reactive protein (CRP) serum levels to predict fever, gram-negative bacteremia and complicated infection in neutropenic patients with cancer. Serum samples were obtained three times a week during 208 neutropenic episodes following cytotoxic chemotherapy. Fever of any cause developed during 104 out of 191 evaluable episodes. Serum levels of neither cytokine nor CRP were predictive of fever within more than 24 h before its onset. Unlike CRP, both IL-6 and IL-8 serum levels were significantly different between microbiologically documented infections and unexplained fevers. The highest values of IL-6 and IL-8 were observed in episodes of gram-negative bacteremia. Using receiver-operating-characteristic curves, the analysis of cytokine levels measured around the onset of fever indicated that IL-8 is potentially useful for predicting gram-negative bacteremia, with a high negative predictive value of > 90% and a moderate positive predictive value of 50% (sensitivity, 70%; specificity, 91%). In patients with persistent fever, predictions of further clinical complications, defined as prolonged fever of more than 7 days' duration, pneumonia, shock and/or death due to infection, were best predicted by IL-6. With an IL-6 cutoff value of 250 pg/ml in samples obtained 8 to 32 h after onset of fever, the positive predictive value was 92%, the negative predictive value 91% (sensitivity, 85%; specificity, 95%). The positive predictive value of IL-6 in samples obtained another 24 h later from patients still febrile remained > 90%, but the negative predictive value dropped to 47%. In any of the analyses, the predictive values of CRP levels were poor and inferior to either cytokine. These findings may have clinical value in identifying subgroups of patients requiring different therapeutic approaches.     

From information to probability: An axiomatic approach—Inference is information processing

We define the very rich language of composed conditionals on a three‐valued logic and use this language as the communication tool between man and machine. Communication takes place for three reasons: knowledge acquisition, query, and response. Learning, thinking, and answering questions are of a pure information theoretical nature. The pivot of this knowledge processing concept is the amount of information (bit) we receive if a conditional becomes true. We follow an axiomatic approach to information theory rather than the classical probabilistic approach of Shannon; information comes first, and then comes probability. In the light of this philosophy, query and response experience new interpretations. Both, acquisition and response are realized by maximizing entropy and minimizing relative entropy, respectively. The iterative solution of these mathematical optimization problems gives new insights into the adaptation of prior knowledge to new information. Our expert system shell SPIRIT supports this kind of knowledge processing, which will be established by suitable examples. © 2003 Wiley Periodicals, Inc.     

Hormonal secretion during nighttime sleep indicating stress of daytime exercise

We tested the hypothesis that long-duration exercise (LDE) of moderate intensity, but not LDE of low intensity, during the daytime changes the typical temporal patterns of hormone release during subsequent nocturnal sleep. Ten trained healthy men participated in a balanced crossover study including three conditions: 1) no exercise, 2) LDE of low intensity (biking 40 km; 1800-2030), and 3) LDE of moderate intensity (biking 120-150 km; 1600-2030). During the subsequent night (2300-0700), somnopolygraphic sleep recordings were obtained, and concentrations of cortisol, growth hormone (GH), and testosterone were measured every 15 min. During the no exercise nights, the typical secretory patterns were present with peak concentrations of GH but nadir concentrations of cortisol during the first half of sleep but increased cortisol levels and minimum GH levels during the second part of sleep. Testosterone concentrations increased during the second half of sleep. LDE of moderate intensity reduced rapid-eye-movement sleep [13.9 vs. 16.9% (no exercise); P < 0.01]. Levels of testosterone decreased with increasing intensity of daytime exercise (P < 0.05). Moderate-, but not low-intensity, LDE decreased GH levels in the first half (P < 0.05) and increased GH levels in the second half (P < 0.005) of sleep. Also, LDE of moderate intensity but not LDE of low intensity increased cortisol levels during the first half (P < 0.005) and decreased cortisol secretion during the second half (P < 0.05) of sleep. Results suggest that nocturnal profiles of GH and cortisol concentrations may serve to indicate the disturbance of normal anabolic functions of sleep due to daytime exercise.     

Analysis of grain boundary movement analogous to dislocation movement – both with a matrix having precipitates

In the present investigation it has been shown exemplarily for an austenite microstructure containing carbonitrides that the specific restraining force of a grain boundary due to the distribution of precipitates can be described by a modified Orowan's law, so that the grain boundary movement is considered to be analogous to the dislocation movement. This is achieved by using a modified restraining force F_r (corresponding to the cubic geometry of the particles), a detailed thermodynamic analysis of the precipitates (in this case, carbonitrides) and selected relation for the interparticle spacing L_a. The specific restraining force and the interparticle spacing depend on temperature within the austenite range. Each temperature is attached to a couple (F_r/L_a). The plot F_r against shows straight lines for each steel and from their average slope, a shear module G' of grain boundaries, which is about 64300 N·cm^?2, is obtained. Hence, it is possible to describe the specific restraining force of a grain boundary with the help of Orowan's law or as it is conventionally done by using Zener's modell. At a critical temperature T*, which is different for each steel, the specific restraining force is equal to the driving force of the grain boundary. The corresponding values of L_a are also different for each steel and the steel which is the most resistant to grain coarsening is allowed to have the greatest value of L_a which still retains the capacity of impeding grain coarsening.     

Driving Automotive User Interface Research

Cars offer an interesting but challenging microcosm for pervasive computing research and, in particular, for interaction with pervasive computing systems. Increasingly, researchers are looking at interactive applications in the car and investigating human-car interaction from a computer science—rather than an ergonomics or mechanical engineering—perspective. This article reports on the International Conference on Automotive User Interfaces and Interactive Vehicular Applications, wherein participants shared presentations on topics such as aesthetics, user interaction and distraction, safety, and driver monitoring.