ATOMISTIC SIMULATIONS OF HYDROGEN EMBRITTLEMENT IN PALLADIUM

Palladium hydrogen system has unique catalytic activities and up to 1:1 hydrogen adsorption capability. It is studied in the context of hydrogen embrittlement, which is a subset of stress corrosion cracking, with classical molecular dynamics techniques. Hydrogen embrittlement is a long lasting metallurgical challenge due to its intractability and unpredictability. First, the thermomechanical properties are studied parametrically in a wide range of hydrogen concentration and temperature, serving a database for hierarchical multiscale simulations and constitutive models in mechanics. To quantitatively describe the kinetics of hydrogen segregation at crack tips, anisotropic diffusion properties are investigated under tensile/compressive loads in both elastic and plastic regions at different temperature and hydrogen concentration. Meanwhile, vacancy concentration as a function of strain is also studied in the same circumstances to quantitatively study the super abundant vacancy phenomenon and how it could initiate hydrogen embrittlement. Further, hydrogen interactions with coherent twin boundary is simulated at finite temperature. The local strength of twin boundary with hydrogen is estimated by molecular dynamics nanoindentation. At last, the heterogeneous nucleation mechanisms of defects under the influence of hydrogen content in single crystal pillars with different growth orientations are investigated to reveal the slip versus twin competition in plastic deformation. In short, a wide range of interesting topics are rigorously explored in the realm of atomistic hydrogen embrittlement

A Case Study on Camberwell Sdn. Bhd

The purpose of this case study is to determine the marketing competitiveness of Camberwell Sendirian Berhad that will give the company a competitive edge. The marketing competitiveness was analyzed using the SWOT analysis, marketing analysis, financial analysis and SPACE MODEL. SWOT analysis was used to determine the overall strengths, weaknesses, opportunities and threats of the company. Marketing analysis was used to determine competitive aspects with respect to product, price, distribution and promotion strategies of the company. Financial analysis was used to ascertain the company situation in terms of debts and profits. SPACE MODEL is to determine the marketing strategy that is going to deploy by the company

Comparative Analysis of CpG Islands in Four Fish Genomes

There has been much interest in CpG islands (CGIs), clusters of CpG dinucleotides in GC-rich regions, because they are considered gene markers and involved in gene regulation. To date, there has been no genome-wide analysis of CGIs in the fish genome. We first evaluated the performance of three popular CGI identification algorithms in four fish genomes (tetraodon, stickleback, medaka, and zebrafish). Our results suggest that Takai and Jones' (2002) algorithm is most suitable for comparative analysis of CGIs in the fish genome. Then, we performed a systematic analysis of CGIs in the four fish genomes using Takai and Jones' algorithm, compared to other vertebrate genomes. We found that both the number of CGIs and the CGI density vary greatly among these genomes. Remarkably, each fish genome presents a distinct distribution of CGI density with some genomic factors (e.g., chromosome size and chromosome GC content). These findings are helpful for understanding evolution of fish genomes and the features of fish CGIs

ATOMISTIC SIMULATIONS OF HYDROGEN EMBRITTLEMENT IN PALLADIUM

Palladium hydrogen system has unique catalytic activities and up to 1:1 hydrogen adsorption capability. It is studied in the context of hydrogen embrittlement, which is a subset of stress corrosion cracking, with classical molecular dynamics techniques. Hydrogen embrittlement is a long lasting metallurgical challenge due to its intractability and unpredictability. First, the thermomechanical properties are studied parametrically in a wide range of hydrogen concentration and temperature, serving a database for hierarchical multiscale simulations and constitutive models in mechanics. To quantitatively describe the kinetics of hydrogen segregation at crack tips, anisotropic diffusion properties are investigated under tensile/compressive loads in both elastic and plastic regions at different temperature and hydrogen concentration. Meanwhile, vacancy concentration as a function of strain is also studied in the same circumstances to quantitatively study the super abundant vacancy phenomenon and how it could initiate hydrogen embrittlement. Further, hydrogen interactions with coherent twin boundary is simulated at finite temperature. The local strength of twin boundary with hydrogen is estimated by molecular dynamics nanoindentation. At last, the heterogeneous nucleation mechanisms of defects under the influence of hydrogen content in single crystal pillars with different growth orientations are investigated to reveal the slip versus twin competition in plastic deformation. In short, a wide range of interesting topics are rigorously explored in the realm of atomistic hydrogen embrittlement

Self-Sampling Meta SAM: Enhancing Few-shot Medical Image Segmentation with Meta-Learning

While the Segment Anything Model (SAM) excels in semantic segmentation for general-purpose images, its performance significantly deteriorates when applied to medical images, primarily attributable to insufficient representation of medical images in its training dataset. Nonetheless, gathering comprehensive datasets and training models that are universally applicable is particularly challenging due to the long-tail problem common in medical images. To address this gap, here we present a Self-Sampling Meta SAM (SSM-SAM) framework for few-shot medical image segmentation. Our innovation lies in the design of three key modules: 1) An online fast gradient descent optimizer, further optimized by a meta-learner, which ensures swift and robust adaptation to new tasks. 2) A Self-Sampling module designed to provide well-aligned visual prompts for improved attention allocation; and 3) A robust attention-based decoder specifically designed for medical few-shot learning to capture relationship between different slices. Extensive experiments on a popular abdominal CT dataset and an MRI dataset demonstrate that the proposed method achieves significant improvements over state-of-the-art methods in few-shot segmentation, with an average improvements of 10.21% and 1.80% in terms of DSC, respectively. In conclusion, we present a novel approach for rapid online adaptation in interactive image segmentation, adapting to a new organ in just 0.83 minutes. Code is publicly available on GitHub upon acceptance

CpG island density and its correlations with genomic features in mammalian genomes

A systematic analysis of CpG islands in ten mammalian genomes suggests that an increase in chromosome number elevates GC content and prevents loss of CpG islands

Features of Methylation and Gene Expression in the Promoter-Associated CpG Islands Using Human Methylome Data

CpG islands are typically located in the 5′ end of genes and considered as gene markers because they play important roles in gene regulation via epigenetic change. In this study, we compared the features of CpG islands identified by several major algorithms by setting the parameter cutoff values in order to obtain a similar number of CpG islands in a genome. This approach allows us to systematically compare the methylation and gene expression patterns in the identified CpG islands. We found that Takai and Jones' algorithm tends to identify longer CpG islands but with weaker CpG island features (e.g., lower GC content and lower ratio of the observed over expected CpGs) and higher methylation level. Conversely, the CpG clusters identified by Hackenberg et al.'s algorithm using stringent criteria are shorter and have stronger features and lower methylation level. In addition, we used the genome-wide base-resolution methylation profile in two cell lines to show that genes with a lower methylation level at the promoter-associated CpG islands tend to express in more tissues and have stronger expression. Our results validated that the DNA methylation of promoter-associated CpG islands suppresses gene expression at the genome level

0-π\pi qubit in one Josephson junction

Quantum states are usually fragile which makes quantum computation being not as stable as classical computation. Quantum correction codes can protect quantum states but need a large number of physical qubits to code a single logic qubit. Alternatively, the protection at the hardware level has been recently developed to maintain the coherence of the quantum information by using symmetries. However, it generally has to pay the expense of increasing the complexity of the quantum devices. In this work, we show that the protection at the hardware level can be approached without increasing the complexity of the devices. The interplay between the spin-orbit coupling and the Zeeman splitting in the semiconductor allows us to tune the Josephson coupling in terms of the spin degree of freedom of Cooper pairs, the hallmark of the superconducting spintronics. This leads to the implementation of the parity-protected 0-$\pi$ superconducting qubit with only one highly transparent superconductor-semiconductor Josephson junction, which makes our proposal immune from the various fabrication imperfections.Comment: 5 pages, 4 figure