X-ray: Discovering DRAM Internal Structure and Error Characteristics by Issuing Memory Commands

The demand for accurate information about the internal structure and characteristics of dynamic random-access memory (DRAM) has been on the rise. Recent studies have explored the structure and characteristics of DRAM to improve processing in memory, enhance reliability, and mitigate a vulnerability known as rowhammer. However, DRAM manufacturers only disclose limited information through official documents, making it difficult to find specific information about actual DRAM devices. This paper presents reliable findings on the internal structure and characteristics of DRAM using activate-induced bitflips (AIBs), retention time test, and row-copy operation. While previous studies have attempted to understand the internal behaviors of DRAM devices, they have only shown results without identifying the causes or have analyzed DRAM modules rather than individual chips. We first uncover the size, structure, and operation of DRAM subarrays and verify our findings on the characteristics of DRAM. Then, we correct misunderstood information related to AIBs and demonstrate experimental results supporting the cause of rowhammer. We expect that the information we uncover about the structure, behavior, and characteristics of DRAM will help future DRAM research.Comment: 4 pages, 7 figure

Correlations between regional characteristics of counties and the ratio of intracounty to extracounty sources of COVID-19 in Gangwon Province, Republic of Korea

Objectives This study aimed to examine the correlations between the regional characteristics of counties in Gangwon Province, Republic of Korea and the ratio of intracounty to extracounty sources of coronavirus disease 2019 (COVID-19) infection. Methods The region of the infectious contact was analysed for each COVID-19 case reported in Gangwon Province between February 22, 2020 and February 7, 2022. The population, population density, area, the proportion of urban residents, the proportion of older adults (>65 years), financial independence, and the number of adjacent counties were assessed for each of the 18 counties in Gangwon Province. Correlation coefficients between regional characteristics and the ratio of intracounty to extracounty infections were calculated. Results In total, 19,645 cases were included in this study. The population, population density, proportion of older adults, and proportion of urban residents were significantly correlated with the ratio of intracounty to extracounty infections. A stratified analysis with an age cut-point of 65 years showed that the proportion of older adults had a significant negative correlation with the ratio of intracounty to extracounty infections. In other words, the proportions of extracounty infections were higher in counties with higher proportions of older adults. Conclusion Regions with ageing populations should carefully observe trends in infectious disease outbreaks in other regions to prevent possible transmission

Gene duplication of type-B ARR transcription factors systematically extends transcriptional regulatory structures in Arabidopsis

Many of duplicated genes are enriched in signaling pathways. Recently, gene duplication of kinases has been shown to provide genetic buffering and functional diversification in cellular signaling. Transcription factors (TFs) are also often duplicated. However, how duplication of TFs affects their regulatory structures and functions of target genes has not been explored at the systems level. Here, we examined regulatory and functional roles of duplication of three major ARR TFs (ARR1, 10, and 12) in Arabidopsis cytokinin signaling using wild-type and single, double, and triple deletion mutants of the TFs. Comparative analysis of gene expression profiles obtained from Arabidopsis roots in wild-type and these mutants showed that duplication of ARR TFs systematically extended their transcriptional regulatory structures, leading to enhanced robustness and diversification in functions of target genes, as well as in regulation of cellular networks of target genes. Therefore, our results suggest that duplication of TFs contributes to robustness and diversification in functions of target genes by extending transcriptional regulatory structures.1

Cas13d binding specificity mitigates off-target activity

CRISPR-Cas13 has been developed as a tool for genome editing by enabling precise RNA manipulation without permanently altering the genome. While its potential in therapeutics and diagnostics is promising, Cas13d’s off-target activities have limited its further use. To enhance our understanding of Cas13d’s binding specificity, we performed a massively parallel filter-binding assay probing the impact of mismatches in the target RNA on binding. Our results revealed that Cas13d binding is greatly affected by the specific position of the mutations in the target sequence, with less dependence on the type of mutation. Mismatches in the 5’ region of the target sequence were well tolerated, while those in the central region abrogated binding. These results emphasize the requirement for a complementary sequence in the central region for specific Cas13d binding. Additionally, this study expands the filter-binding method as a valuable tool for analyzing the binding specificity and off-target effects of Cas13d. Thus, our work lays a solid foundation for future high-throughput profiling of Cas13d binding and applying Cas13d for safe and effective transcriptional perturbation

Electrically Stretchable Color Change Using Chiral Photonic Gels

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Analytical Study of Bi-Layered Chiral Liquid Crystal Photonic Band Filter

Owing to their peculiar helical structure, Chiral Liquid Crystals (CLCs) are well known for the selective spectral photonic band. This unique photonic band property is resulted from the optical rotation effect of electromagnetic wave propagation depending on the material birefringence (Δn) and rotational repeating pitch (p) following the elegant equation Δλ=Δn·p. Hitherto, a number of researchers have investigated the photonic bandgaps (PBGs) control of this fascinating chiral liquid crystal materials for various applications [1,2]. In particular, over visible wavelength range, the concept of the selective color filter exploiting the optical characteristics of CLCs can be suggested beyond the Bayer color filter which is based on chemical dye absorption. Especially, from the well design of chiral liquid crystal parameter, well controllable tuning of the wavelength position is possible in CLC band filter. In addition to the single CLC structure, bi-layered CLCs can be approached for further elaborate photonic filters [3].Herein, we studied a mathematical analysis of the reflection and transmission spectra of the bilayer CLC photonic color filter modeling. Through this analytical modeling, it was possible to achieve an in-depth understanding of the optical properties of the bilayer CLC color filter. In addition, this study will contribute to exploring a variety of further promising CLC applications including selective band filters and other various photonics sensing applications.1

Optical Characteristics of Deformable Photonic Gels based on Chiral Nematic Liquid Crystal Polymers

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