Serine palmitoyltransferase (SPT) is a key enzyme in the first step of sphingolipid biosynthesis. Mutations in the SPTLC1 gene that encodes for SPT subunits cause hereditary sensory neuropathy type 1. However, little is understood about how mutant SPT regulates mechanisms of sensory neuron and axonal growth. Using transgenic mice overexpressing the C133W SPT mutant, we found that mutant dorsal root ganglia (DRG) during growth in vitro exhibit increased neurite length and branching, coinciding with elevated expression of actin-cross-linking proteins at the neuronal growth cone, namely phosphorylated Ezrin/Radixin/Moesin. In addition, inhibition of SPT was able to reverse the mutant phenotype. Because mutant SPT preferentially uses L-alanine over its canonical substrate L-serine, we also investigated the effects of substrate availability on DRG neurons. Supplementation with L-serine or removal of L-alanine independently restored normal growth patterns in mutant SPTLC1 C133W DRG. Therefore, we report that substrate availability and selectivity of SPT influence the regulation of neurite growth in DRG neurons.

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In this paper, it is introduced characteristics of FMCW-type Radar Altimeter for KUH, and its defects occurred during ground/flight test in initial product phase. In addition, it is also described 'data/control flow model' based fault analysis results of S/W and processes of verifying improvement design through flight test as well as aircraft system integration test called MEP SIL. As a result of design improvement and verification, it is validated that settling the defects and improving not only safety but also capability of the KUH.

The electrical power system of Korean Utility Helicopter(KUH) is designed as a dual control system to enhance the system safety of aircraft and each system is installed separately at left and right of the aircraft. The system is composed of 2 AC generators, 1 APU generator, 2 Transformer Rectifier Units(TRU), AC/DC Electrical Master Box(AC/DC EMB). The AC/DC EMB, consists of 2 AC EMB and 2 DC EMB, is essential equipment which supply and distribute electric power to the aviation electronics and electrical equipment of KUH. There were defects caused by internal short circuit in AC EMB during the first production phase of the KUH. This paper describes the analysis of the defects, troubleshooting process, root cause, and the solution by design change.