Early detection of thermoacoustic instability in a staged single-sector combustor for aircraft engines using symbolic dynamics-based approach.

We experimentally conduct an early detection of thermoacoustic instability in a staged single-sector combustor using a novel methodology that combines symbolic dynamics and machine learning. We propose two invariants in this study: the determinisms of the joint symbolic recurrence plots DJ and the ordinal transition pattern-based recurrence plots DT. These invariants enable us to capture the phase synchronization between acoustic pressure and heat release rate fluctuations associated with a precursor of thermoacoustic instability. The latent space consisting of DJ and DT, which is obtained by a support vector machine in combination with the k-means clustering method, can appropriately determine a transitional regime between stable combustion and thermoacoustic instability.

Beef extract supplementation promotes myoblast proliferation and myotube growth in C2C12 cells.

PURPOSE: We previously determined that the intake of beef extract for 4 weeks increases skeletal muscle mass in rats. Thus, this study aimed to clarify whether beef extract has a hypertrophic effect on muscle cells and to determine the signaling pathway underlying beef extract-induced myotube hypertrophy. METHODS: We assessed the effects of beef extract supplement on mouse C2C12 skeletal muscle cell proliferation and differentiation and myotube growth. In addition, the phosphorylation of Akt, ERK1/2, and mTOR following beef extract supplementation was examined by western blotting. Furthermore, the bioactive constituents of beef extract were examined using amino acid analysis and dialysis. RESULTS: In the proliferative stage, beef extract significantly increased myoblast proliferation. In the differentiation stage, beef extract supplementation did not promote myoblast differentiation. In mature myotubes, beef extract supplementation increased myotube diameter and promoted protein synthesis. Although Akt and ERK1/2 levels were not affected, beef extract supplementation increased mTOR phosphorylation, which indicated that the mTOR pathway mediates beef extract-induced myotube hypertrophy. The hypertrophic activity was observed in fractions of > 7000 Da. CONCLUSIONS: Beef extract promoted C2C12 myoblast proliferation and C2C12 myotube hypertrophy. Myotube hypertrophy was potentially induced by mTOR activation and active components in beef extract were estimated to be > 7000 Da.

Fatty acid tryptamide from cacao elongates Drosophila melanogaster lifespan with sirtuin-dependent heat shock protein expression.

Life span is increasing in developed countries as Japan, and an aging society is becoming a problem. In fact, healthy lifespan is not extended, and it is desired to extend it by functional food. Cacao (Theobroma cacao) contains various active components and is considered a preventative agent against metabolic disease. In addition, it has long been thought that regular cacao intake extends a healthy lifespan. However, there is no direct evidence for this belief. The purpose of this study is to identify the cacao component that elongate the lifespan of D. melanogaster as a model organism and to elucidate its functional mechanism. The activation of sirtuins, a family of NAD+-dependent deacetylases, has been reported to extend the lifespans of various organisms. Heat shock factor 1 is known to be deacetylated by reaction with sirtuins, thereby inducing gene expression of various heat shock proteins by heat stress and effectively extending the lifespan of organisms. Therefore, we evaluated whether components in cacao activate sirtuins and extend the lifespan of D. melanogaster. In the process, we discovered the fatty acid tryptamide as a lifespan-elongating component of cacao. Therefore, we investigated whether the fatty acid tryptamide from cacao upregulates the genes of heat shock proteins. As a result, it was confirmed that the gene expression of multiple heat shock proteins was significantly increased. This suggests that fatty acid tryptamide may activate sirtuins, increase gene expression of heat shock proteins, and elongate the lifespan of D. melanogaster.

Effect of dietary fat type on anxiety-like and depression-like behavior in mice.

Dietary fat plays an important role in higher brain functions. We aimed to assess the short and long term intake of three different types of dietary fat (soybean oil, lard, and fish oil) on anxiety-like and depression-like behavior in mice. For the short term intake assessment, a behavioral test battery for anxiety and depression was carried out for a 3-day feeding period. For the long term intake assessment, a behavioral test battery began after the 4-week feeding period. During the short term intake, the time spent in the open arms of the elevated plus-maze was the longest in the fish oil fed group, followed by the soybean oil and lard-fed groups. The elevated plus-maze is a common animal model to assess anxiety, in which an increased time spent in the open arms indicates an anxiolytic effect. The difference between the fish oil-fed group and lard-fed group was statistically significant (p < 0.01), but there was no significant difference between the soybean oil-fed group and the other two groups. Similar results were observed after a 4-week feeding period. On the other hand, there was no significant difference among the three groups in behavior tests to evaluate depression. Thus, the dietary fat types appeared to influence anxiety but not depression in mice, both in short term (3 days) and long term (4 weeks) feeding.