Physiology of Cerebellar Reserve: Redundancy and Plasticity of a Modular Machine

The cerebellum is endowed with the capacity for compensation and restoration after pathological injury, a property known as cerebellar reserve. Such capacity is attributed to two unique morphological and physiological features of the cerebellum. First, mossy fibers that convey peripheral and central information run mediolaterally over a wide area of the cerebellum, resulting in the innervation of multiple microzones, commonly known as cerebellar functional units. Thus, a single microzone receives redundant information that can be used in pathological conditions. Secondly, the circuitry is characterized by a co-operative interplay among various forms of synaptic plasticity. Recent progress in understanding the mechanisms of redundant information and synaptic plasticity has allowed outlining therapeutic strategies potentiating these neural substrates to enhance the cerebellar reserve, taking advantage of the unique physiological properties of the cerebellum which appears as a modular and potentially reconfiguring brain structure.     

Regulatory Role of Sugars on the Settlement Inducing Activity of a Conspecific Cue in Pacific Oyster Crassostrea gigas

This study evaluated the larval settlement inducing effect of sugars and a conspecific cue from adult shell extract of Crassostrea gigas. To understand how the presence of different chemical cues regulate settlement behavior, oyster larvae were exposed to 12 types of sugars, shell extract-coated and non-coated surfaces, and under varied sugar exposure times. Lectin-glycan interaction effects on settlement and its localization on oyster larval tissues were investigated. The results showed that the conspecific cue elicited a positive concentration dependent settlement inducing trend. Sugars in the absence of a conspecific cue, C. gigas adult shell extract, did not promote settlement. Whereas, in the presence of the cue, showed varied effects, most of which were found inhibitory at different concentrations. Sugar treated larvae exposed for 2 h showed significant settlement inhibition in the presence of a conspecific cue. Neu5Ac, as well as GlcNAc sugars, showed a similar interaction trend with wheat germ agglutinin (WGA) lectin. WGA-FITC conjugate showed positive binding on the foot, velum, and mantle when exposed to GlcNAc sugars. This study suggests that a WGA lectin-like receptor and its endogenous ligand are both found in the larval chemoreceptors and the shell Ethylenediaminetetraacetic acid (EDTA) extract that may complementarily work together to allow the oyster larva greater selectivity during site selection.     

Renal Cyclooxygenase Products are Higher and Lipoxygenase Products are Lower in Early Disease in the pcy Mouse Model of Adolescent Nephronophthisis

Nephronophthisis (NPHP) is a pediatric form of hereditary polycystic kidney disease (PKD), and is the leading cause of end stage renal disease in children. The pcy mouse is an orthologous model of human NPHP, with a mutation in the Nphp3 gene. Renal phospholipase A₂, cyclooxygenase (COX) 1 and cyclic AMP are elevated in this model, suggesting that eicosanoid formation may be altered. In another type of PKD observed in the Han:SPRD-Cy rat, inhibition of eicosanoid production slows disease progression. If renal eicosanoids are similarly altered in NPHP, potential for pharmacologic intervention also may exist for this disorder. Therefore, renal fatty acids and eicosanoids were determined in pcy and normal mice at 15, 30 and 60 days of age by gas chromatography and HPLC–tandem mass spectrometry, respectively. Renal cysts in enlarged kidneys were observed in pcy mice by 15 days of age and increased over time. Renal phospholipid ARA levels were higher in pcy compared to normal mice at 15 and 30 days. Eicosanoid differences were observed starting at 30 days, when the COX products 6-keto-prostaglandin (PG) F_1α, thromboxane B₂ and PGE₂ were higher in pcy compared to normal kidneys. Overall, total COX products were elevated at 30 and 60 days. In contrast, the levels of the lipoxygenase (LOX) products were not altered until 60 days of age and these were lower in pcy kidneys compared to normal. These findings suggest that altered eicosanoids play a role in NPHP, and that manipulating these levels with pharmacologic agents may have therapeutic potential.     

High-temperature electro-ceramics and their application to SiC power modules

This paper presents the research achievement in Japan to develop highly-refractive electro-ceramics for application to silicon carbide (SiC) power modules such as heat-resistive passive components (snubber capacitors and resistors), metalised substrates, ceramic circuit boards, and high-temperature packaging technologies. To enable the operation of SiC devices at high temperatures, the ability to withstand 250 °C and temperature cycle between ?40 and 250 °C must be ensured for all the ceramic components and packaging technologies. For the passive components, the following properties were achieved, which would enable the operation of SiC devices at high switching speeds and high temperatures: low-resistance resistors which exhibit a resistance variation of less than 2% over a temperature range of ?40 to 250 ℃ and with almost no variation at frequencies of less than 10 MHz; multi-layered ceramic capacitors (MLCCs) with a capacitance variation of less than ± 10% within the above-mentioned temperature range and with high self-resonant frequencies of about 10 MHz. In addition, Cu-metalised ceramic substrates using high thermal conductive Si₃N₄ (180 W /(m·K)) and ceramic circuit boards produced using a co-firing process were developed. It was shown that prototype SiC power modules (2-in-1 structure) fabricated using the developed ceramic components could be operated at 225 °C, while exhibiting a high switching speed, 10–20 times faster than that of conventional Si IGBT (150 °C operation).     

A Study on High Subsonic Airfoil Flows in Relatively High Reynolds Number by Using OpenFOAM

In the present study, numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows. The airfoil model is NACA 64A010. The maximum thickness is 10 % of the chord length. The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows. The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively. The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past. The results are as follows. The nu- merical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel. And the data calcu- lated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low an- gle of attack.     

Fused silica contamination layer removal using magnetic field-assisted finishing

Fused silica optics used in lasing systems requires a high laser-induced damage resistance. Processes typically used to polish fused silica lenses induce subsurface and surface damage that collect ceria abrasive, creating a layer of contamination. The contamination can be a precursor to laser damage during use. A preliminary study showed the feasibility of magnetic field-assisted finishing (MAF) for polishing fused silica and suggested possible beneficial effects of the MAF-polished surface on the laser-induced damage threshold (LIDT). This paper proposes a method to examine the fundamental polishing characteristics of MAF for fused silica. Using the proposed method, this paper explores the material removal characteristics of the MAF process and improves the understanding of the MAF polishing mechanism. The 45% improvement of LIDT shows the efficacy of MAF for removing the contamination layer of fused silica surfaces with minimal changes in the surface roughness.     

Surface smoothing and repairing of additively manufactured metal products by large-area electron beam irradiation

In general, surface of additively manufactured (AMed) metal products has large roughness due to arrangement of bead shapes, and surface irregularities such as spatter and cavity. Furthermore, surface elemental composition of AMed products may be changed from that of metal powder. In this study, efficient surface smoothing and repairing of AMed metal products by large-area electron beam irradiation were experimentally investigated. Experimental results show that spatter and cavity can be completely removed and surface roughness significantly reduces. Elemental composition of AMed surface can be also changed to that of original metal powder due to the removal of oxidized surface.