The «nanoscalpel» for microsurgery of glial brain tumours

Glial tumours are among the most common primary brain tumours of neuroectodermal origin characterised by infiltrative growth and widespread invasion of tumour cells into healthy tissue. A highly demanded method for therapy of such tumours may become magnetomechanical microsurgery substituting the scalpel with the «nanoscalpel» consisting of: (1) nanostructures converting the magnetic moment into the mechanical one, and (2) targeted ligands. Suitable structures for the nanoscalpel are magnetic disks with a high degree of saturation magnetisation and absent remanent magnetisation. The search for publications dated 1992-2021 was carried out in the PubMed and e-LIBRARY databases. The search keywords were «magnetic discs», «glial tumors», «microsurgery» and «magnetomechanical transduction». This review discusses biological effects of magnetic disks, their mechanism of action and toxicity. It has been concluded that a «nanoscalpel» remotely controlled using a magnetic field may become an effective and safe tool for microsurgery of glial brain tumours.

Investigation of Smear Formation Mechanism From DLC Film by Heating

The formation of head smear from DLC films on magnetic disks was confirmed by a simulated heating experiment. DLC films of 100-nm thickness were prepared and heated on a hot plate in an environmental gas chamber. Smear on a silicon wafer placed 3 mm above the DLC surface was observed after heating of the DLC film. The smear amount was quantified using the carbon intensity of the smear measured by XPS. In air, the carbon concentration decreased with the heating temperature; however, the carbon concentration increased with temperature in nitrogen. The carbon concentration of the smear in the air environment was smaller than that of nitrogen. As the result of comparison of smears on DLCs with various hydrogen concentrations, more decomposed gas is generated from the DLC film as the amount of hydrogen contained in the DLC increases, and this value increases at lower temperatures. This result suggests that DLC films with low hydrogen concentrations generate a smaller amount of decomposition gas than those with high hydrogen concentrations during heating. In addition, Raman spectra suggest that the DLC degraded by heating and the hydrocarbon gas-like materials were generated from the DLC film because the DLC films include carbon and hydrogen. Because fragments of 250–500 atomic mass units were observed in the TOF-SIMS spectra of smears, the smear is estimated to consist of a hydrocarbon of relatively high molecular weight.

Influence of different factors on the RAID 0 paired magnetic disk arrays

The rapid technological progress has led to a growing need for more data storage space. The appearance of big data requires larger storage space, faster access and exchange of data as well as data security. RAID (Redundant Array of Independent Disks) technology is one of the most cost-effective ways to satisfy needs for larger storage space, data access and protection. However, the connection of multiple secondary memory devices in RAID 0 aims to improve the secondary memory system in a way to provide greater storage capacity, increase both read data speed and write data speed but it is not fault-tolerant or error-free. This paper provides an analysis of the system for storing the data on the paired arrays of magnetic disks in a RAID 0 formation, with different number of queue entries for overlapped I/O, where queue depth parameter has the value of 1 and 4. The paper presents a range of test results and analysis for RAID 0 series for defined workload characteristics. The tests were carried on in Microsoft Windows Server 2008 R2 Standard operating system, using 2, 3, 4 and 6 paired magnetic disks and controlled by Dell PERC 6/i hardware RAID controller. For the needs of obtaining the measurement results, ATTO Disk Benchmark has been used. The obtained results have been analyzed and compared to the expected behavior.

Vortex Annihilation Dependence of Chirality in Asymmetric Permalloy Dots

Geometric asymmetry effect on vortex annihilation was investigated in series of submicro-scaled permalloy dots. By introducing the one-side-flat asymmetric shape into circular magnetic disks, the original degenerate signals of vortex annihilation for different chirality are separated into two different trajectories, where the asymmetry level is quantified by an excised angle. The separation of annihilation field for clockwise and counterclockwise vortex shows as a function of the excised angle. The asymmetry influence on the separation of annihilation field is discussed from the view of disk aspect ratio and flat boundary effect. Comparison of experimental results with numerical simulations is also presented.