417 research outputs found
Resonant waves in the gap between two advancing barges
The gap resonance between two advancing rectangular barges in side-by-side arrangement is investigated using a 3-D Rankine source method. A modified Sommerfeld radiation condition accounting for Doppler shift is applied for the low forward speed problem when the scattered waves could propagate ahead of the barges. Numerical studies are conducted to investigate various factors which will influence the wave resonance in the narrow gap with particular attention paid on the forward speed effect and its coupling effects with gap width and draft. It is found that in the absence of forward speed, the trapped water surface oscillates like a flexible plate and the wave flow within the gap behaves like a standing wave. When the two barges are travelling ahead, the resonant wave patterns within the gap are reshaped. Additionally, the resonant frequencies shift to lower value and are compressed within a narrow range. Gap resonances are reduced by the augment of gap width. The effect of draft is shown to be associated with resonant modes. Draft effect becomes less pronounced at higher order resonant modes. Furthermore, both gap width and draft effects on gap resonance are found to be independent from forward speed
DHX33 transcriptionally controls genes involved in the cell cycle
The RNA helicase DHX33 has been shown to be a critical regulator of cell proliferation and growth. However, the underlying mechanisms behind DHX33 function remain incompletely understood. We present original evidence in multiple cell lines that DHX33 transcriptionally controls the expression of genes involved in the cell cycle, notably cyclin, E2F1, cell division cycle (CDC), and minichromosome maintenance (MCM) genes. DHX33 physically associates with the promoters of these genes and controls the loading of active RNA polymerase II onto these promoters. DHX33 deficiency abrogates cell cycle progression and DNA replication and leads to cell apoptosis. In zebrafish, CRISPR-mediated knockout of DHX33 results in downregulation of cyclin A2, cyclin B2, cyclin D1, cyclin E2, cdc6, cdc20, E2F1, and MCM complexes in DHX33 knockout embryos. Additionally, we found the overexpression of DHX33 in a subset of non-small-cell lung cancers and in Ras-mutated human lung cancer cell lines. Forced reduction of DHX33 in these cancer cells abolished tumor formation in vivo. Our study demonstrates for the first time that DHX33 acts as a direct transcriptional regulator to promote cell cycle progression and plays an important role in driving cell proliferation during both embryo development and tumorigenesis
HL-DPoS: An Enhanced Anti-Long-Range Attack DPoS Algorithm
The consensus algorithm is crucial in blockchain for ensuring the validity
and security of transactions across the decentralized network. However,
achieving consensus among nodes and packaging blocks in blockchain networks is
a complex task that requires efficient and secure consensus algorithms. The
DPoS consensus algorithm has emerged as a popular choice due to its fast
transaction processing and high throughput. Despite these advantages, the
algorithm still suffers from weaknesses such as centralization and
vulnerability to long-range attacks, which can compromise the integrity of the
blockchain network.
To combat these problems, we developed an Enhanced Anti-Long-Range Attack
DPoS algorithm (HL-DPoS). First, we split nodes into pieces to reduce
centralization issues while giving witness nodes the power to report and
benefit from malicious node's reports, maintaining high efficiency and high
security. Second, we propose a validation method in HL-DPoS that compares
consensuses transactions with the longest chain to detect long-range attacks.
Algorithm analysis and simulation experiment results demonstrate that our
HL-DPoS consensus algorithm improves security while achieving better consensus
performance
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