The diffusion of hydrogen and inert gas in sputtered a-SiC:H alloys: Microstructure study

The microstructure of DC sputtered amorphous silicon carbon (a-SiC:H) is studied by effusion measurements of hydrogen and of implanted inert gases helium, neon, argon and secondary ion mass spectrometry. The results suggest that the motion of inert gas atoms is controlled by the diffusion, greatly depending on a broadening of network openings. Already at carbon concentrations of 25 at%, isolated voids disappeared presumably because interconnected voids are formed. A void formation is mainly attributed to an increase in hydrogen incorporation in the samples.     

Acetaldehydbildung im Verlauf der G?rung in Abh?ngigkeit vom Wuchsstoffgehalt des G?rsubstrates I. Mitteilung

Zusammenfasmng In einem Literaturüberblick wird zunächst über die gesundheitliche Bedenklichkeit der schwefligen Säure im Wein berichtet. Sic wird dem Wein zugesetzt, um Acetaldehyd zu binden, der, wenn er in freier Form vorliegt, dem Wein einen unangenehmen Luftgeschmack verleiht. Der Acetaldehyd ist aus diesem Grunde die Ursache für den mehr oder weniger hohen SO₂-Bedarf von Weinen.

---

Formation of Acetaldehyde during Fermentation in Relation to Contents of Growth Substance in the Fermentation Substrate

Summary In experiments with natural and synthetic substrates it is demonstrated that fermentation varied, depending on the presence of growth substances. High concentrations of pyruvic acid indicated a growth substance deficiency; addition of vitamins influenced the metabolism of fermentation in a similar way as the other biological substances. The formation of fermentation by-products was also influenced by growth substances.

---

---

Semmler, G.: Auszüge aus der im Fach Lebensmitteltechnologie angefertigten Dissertation an der Justus-Liebig-Universität in Gießen.     

Interventional magnetic resonance imaging: an alternative to image guidance with ionising radiation

At present, interventional procedures, such as stent placement, are performed under X-ray image guidance. Unfortunately with X-ray imaging, both patient and interventionalist are exposed to ionising radiation. Furthermore, X-ray imaging is lacking soft tissue contrast and is not capable of true 3-D displays of either interventional device or tissue morphology. Magnetic resonance imaging (MRI) offers excellent soft tissue contrast, 3-D acquisition techniques, as well as rapid image acquisition and reconstruction. Despite these advantages, MR-guided interventions are challenging owing to the limited access to the patient, strong magnetic and radio-frequency fields that require special interventional devices, inferior image frame rates and spatial resolution, and high MRI scanner noise. For MR-guided intravascular interventions, where access to the target organ is achieved through catheters, dedicated hardware and automated image slice positioning techniques have been developed. We illustrate that MR-guided renal embolisations can be performed in closed-bore high-field MR scanners.     

An MR-compatible stereoscopic in-room 3D display for MR-guided interventions

Background and methods

A commercial three-dimensional (3D) monitor was modified for use inside the scanner room to provide stereoscopic real-time visualization during magnetic resonance (MR)-guided interventions, and tested in a catheter-tracking phantom experiment at 1.5 T. Brightness, uniformity, radio frequency (RF) emissions and MR image interferences were measured.

Results and discussion

Due to modifications, the center luminance of the 3D monitor was reduced by 14 %, and the addition of a Faraday shield further reduced the remaining luminance by 31 %. RF emissions could be effectively shielded; only a minor signal-to-noise ratio (SNR) decrease of 4.6 % was observed during imaging. During the tracking experiment, the 3D orientation of the catheter and vessel structures in the phantom could be visualized stereoscopically.     

MR safety: simultaneous B 0, d��/dt, and dB/dt measurements on MR-workers up to 7 T

Object

The EU directive on safety requirements (2004/40/EC) limits the exposure to time varying magnetic fields to dB /dt = 200 mT/s. This action value is not clearly defined as it considers only the temporal change of the magnitude of ${\vec {B}}$ . Thus, only the translational motion in the magnet??s fringe field is considered and rotations are neglected.

Materials and methods

A magnetic field probe was constructed to simultaneously record the magnetic flux density ${\vec{B}}$ (x, y, z) with a 3-axis Hall sensor and the induced voltage due to movements with a set of three orthogonal coils. Voltages were converted into time-varying magnetic flux d ??(x, y, z)/dt serving as an exposition parameter for both translations and rotations. To separate the two types of motion, d B/dt was additionally calculated on the basis of the Hall sensor??s data. The calibrated probe was attached to the forehead of 8 healthcare workers and 17 MR physicists, and ${\vec {B}}$ and d??/dt were recorded during standard operating procedures at three different MR systems up to 7 T.

Results

The maximum percentage of the translational motion referring the data including both translations and rotations amounts to 32%. During volunteer measurements, maximum exposure values of d??/dt = 21 mWb/s, dB/dt = 1.40 T/s and ${\left| {\vec {B}}\right|= 2.75}$ Twere found.

Conclusion

The findings in this work indicate that both translations and rotations in the vicinity of an MR system should be taken into account, and that a single regulatory action level might not be sufficient.     

Modern Methods of Analysis in Mineral Raw Materials Industry

The development of analytical chemistry in the past decades has provided the raw materials industry with a wealth of new methods and procedures for the characterization of raw, intermediate and final products. The greatest advances were made in trace and micro analytical methods. These are now routinely available at reasonable cost and turnaround times. Equally significant for the industry is the development of process analytical methods for bulk properties that provide crucial information for successful automation of complex processes.     

How miRNAs Regulate Schwann Cells during Peripheral Nerve Regeneration—A Systemic Review

A growing body of studies indicate that small noncoding RNAs, especially microRNAs (miRNA), play a crucial role in response to peripheral nerve injuries. During Wallerian degeneration and regeneration processes, they orchestrate several pathways, in particular the MAPK, AKT, and EGR2 (KROX20) pathways. Certain miRNAs show specific expression profiles upon a nerve lesion correlating with the subsequent nerve regeneration stages such as dedifferentiation and with migration of Schwann cells, uptake of debris, neurite outgrowth and finally remyelination of regenerated axons. This review highlights (a) the specific expression profiles of miRNAs upon a nerve lesion and (b) how miRNAs regulate nerve regeneration by acting on distinct pathways and linked proteins. Shedding light on the role of miRNAs associated with peripheral nerve regeneration will help researchers to better understand the molecular mechanisms and deliver targets for precision medicine.     

Real-time MR navigation and localization of an intravascular catheter with ferromagnetic components

Object  

To develop an intravascular catheter with ferromagnetic components that is navigated with MR gradient forces and imaged with dedicated MR sequences in real time.