Comparing the Toxicological Responses of Pulmonary Air-Liquid Interface Models upon Exposure to Differentially Treated Carbon Fibers

In recent years, the use of carbon fibers (CFs) in various sectors of industry has been increasing. Despite the similarity of CF degradation products to other toxicologically relevant materials such as asbestos fibers and carbon nanotubes, a detailed toxicological evaluation of this class of material has yet to be performed. In this work, we exposed advanced air-liquid interface cell culture models of the human lung to CF. To simulate different stresses applied to CF throughout their life cycle, they were either mechanically (mCF) or thermo-mechanically pre-treated (tmCF). Different aspects of inhalation toxicity as well as their possible time-dependency were monitored. mCFs were found to induce a moderate inflammatory response, whereas tmCF elicited stronger inflammatory as well as apoptotic effects. Furthermore, thermal treatment changed the surface properties of the CF resulting in a presumed adhesion of the cells to the fiber fragments and subsequent cell loss. Triple-cultures encompassing epithelial, macrophage, and fibroblast cells stood out with an exceptionally high inflammatory response. Only a weak genotoxic effect was detected in the form of DNA strand breaks in mono- and co-cultures, with triple-cultures presenting a possible secondary genotoxicity. This work establishes CF fragments as a potentially harmful material and emphasizes the necessity of further toxicological assessment of existing and upcoming advanced CF-containing materials.

[Clinical evaluation of evidence-based criteria for CT diagnostics in the treatment of mild traumatic brain injury]

AIM

The mild traumatic brain injury (MTBI) is one of the most frequent diseases treated in emergency departments. Extensive studies addressing evidence-based treatment criteria have been published, the indication for CT scans depending on clinical symptoms appeared to be one of the critical issues. In this study, the question was raised whether or not the developed evidence-based criteria may be transferred to the patients of a German level 1 trauma centre.

PATIENTS AND METHODS

Within 2 years (2004/05) 1841 patients with a traumatic brain injury were treated, 1042 patients with a mild traumatic brain injury and with an age over 14 years were included in the study. The indication for a head CT scan was checked by criteria of a phase 3 study (New Orleans Criteria - NOC). Furthermore, the length of hospitalisation, number and character of secondary aggravation, and kind of inpatient care were analysed.

RESULTS

69.5 % of our patients were diagnosed with the help of a CT scan, according to the evidence criteria 98.8 % of the patients should have been scanned (p > 0.001). A secondary aggravation caused by a cerebral lesion was found in 3 patients without a CT scan, all of these patients would have been scanned according to the NOC (n. s.). The fraction of patients with alcohol intoxication reached 44 %, a rate that is significantly higher compared to other international studies. These patients were not as often scanned (p < 0.001) and had a shorter hospital stay (p < 0.001) compared to other patients. Duration of hospital stay was prolonged depending on the severity of the brain injury and occurrence of secondary aggravation (p < 0.001).

CONCLUSION

Summarising, the high sensitivity of the investigated evidence-based criteria (NOC) could be confirmed, but the application would not have led to a reduction of CT scans within our population.

Targeted-HASTE imaging with automated device tracking for MR-guided needle interventions in closed-bore MR systems

Percutaneous MR-guided interventions with needles require fast pulse sequences to image the needle trajectory with minimal susceptibility artifacts. Spin-echo pulse sequences are well suited for reducing artifact size; however, even with single-shot turbo spin-echo techniques, such as rapid acquisition with relaxation enhancement (RARE) or half-Fourier acquisition single-shot turbo spin-echo (HASTE), fast imaging remains challenging. In this work we present a HASTE pulse sequence that is combined with inner-volume excitation to reduce the scan time and limit the imaging field of view (FOV) to a small strip close to the needle trajectory (targeted-HASTE). To compensate for signal saturation from fast repeated acquisitions, a magnetization restore pulse (driven equilibrium Fourier transform (DEFT)) is used. The sequence is combined with dedicated active marker coils to measure the position and orientation of the needle so that the targeted-HASTE image slice is automatically repositioned. In an animal experiment the coils were attached to an MR-compatible robotic assistance system for MR-guided interventions. Needle insertion and infusion via the needle could be visualized with a temporal resolution of 1 s, and the needle tip could be localized even in the presence of a stainless steel mandrel.

Phase unwrapping with the branch-cut method: role of phase-field direction

Phase unwrapping with the branch-cut method has been successfully used in many different applications in recent years. Most methods to set the branch cuts minimize the overall cut length. However, this technique fails in different cases, since this criterion is based mainly on statistical examinations. We show how the orientation and direction of the phase map help to create additional physical criteria that can be used to optimize the setting of the branch cuts. We show how these new criteria can be implemented into an energy function that will be minimized by a simulated annealing algorithm in order of a correct setting of the branch cuts. Finally, we present experimental results from electronic speckle pattern interferometry and digital holography phase maps.

Phase unwrapping with the branch-cut method: clustering of discontinuity sources and reverse simulated annealing

The branch-cut method is a powerful tool for correct unwrapping of phase maps in optical metrology. However, this method encounters the problem of the correct setting of the cuts, which belongs to the class of nondeterministic-polynomial-time-complete problems. Simulated annealing is an algorithm used to solve problems of this kind in a polynomial-time execution. However, the algorithm still requires an enormous calculation time if the number of discontinuity sources and thus the number of branch cuts is high. We illustrate the motivation for the use of this algorithm and show how the running time can be severely reduced by use of reverse simulated annealing, starting from the nearest-neighbor solution to find a proper initial configuration, and by clustering of discontinuity sources.

An exceptional group-I intron-like insertion in the SSU rDNA of lichen mycobionts

An exceptional group-I intron-like insertion at position 940 of the nuclear small subunit rDNA is found in lichen mycobionts of the families Parmeliaceae and Lecanoraceae. This shared insertion site is exceptional as it follows a G. Although several features of the self-splicing Tetrahymena intron are missing, the conserved structure of the presumed core region indicates that the new intron-like insertion, which is missing in mature transcripts, is not part of a silenced ribosomal repeat. It is unlikely that the new insertion is horizontally transferred from the adjacent position 943. A phylogenetic analysis indicates congruence with lichen phylogeny and suggests that the insertion has been vertically inherited.

Phase-shifter calibration and error detection in phase-shifting applications: a new method

The phase-shifting technique is used in optical metrology to evaluate the local phase of a fringe pattern. Accurate calibration of the shifting device is often essential but sometimes hardly possible because of deviations of the fringe pattern from the ideal sinusoidal shape and because of a nonconstant phase shift between consecutive frames. We introduce a new technique for calculating the phase shift between frames even in the presence of high noise and nonsinusoidal fringe patterns. In addition, this technique permits the identification of different error sources such as low signal-to-noise ratio, higher harmonics contained in the fringe pattern, and nonconstant phase shift.

Application of fuzzy-rule-based postprocessing to correlation methods in pattern recognition

The use of fuzzy-logic techniques on the correlation output plane is analyzed as a method to improve the discrimination capabilities of pattern-recognition procedures. The study is divided into two parts: one recounts a computer-simulated example corresponding to pattern recognition by the use of input images that may be defocused, tilted, or corrupted by additive Gaussian noise, and the second part describes an experimental setup in which the deformation of foam material is studied.