244 research outputs found

    Serial Maximum a Posteriori Detection of Two-Dimensional Generalized Partial Response Target for Holographic Data Storage Systems

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    Holographic data storage (HDS) is an emerging technology that promises to revolutionize digital data storage and access. Unlike traditional storage media such as hard drives and flash memory, HDS uses light to write and read page-oriented two-dimensional (2D) data from volume media. This allows for significantly higher densities and faster data transfer rates in HDS systems. However, 2D interference is a serious issue in HDS due to hologram dispersion during the reading process. Therefore, we present a novel detection algorithm based on maximum a posteriori (MAP) detection to mitigate 2D interference. In our proposed model, we inherited the structure of the serial generalized partial response target to design the serial structure for MAP detection. The simulation results show that the proposed model can achieve a high bit error rate performance

    Heterogeneous Integration of Freestanding Bilayer Oxide Membrane for Multiferroicity

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    Transition metal oxides exhibit a plethora of electrical and magnetic properties described by their order parameters. In particular, ferroic orderings offer access to a rich spectrum of fundamental physics phenomena, in addition to a range of technological applications. The heterogeneous integration of ferroelectric and ferromagnetic materials is a fruitful way to design multiferroic oxides. The realization of freestanding heterogeneous membranes of multiferroic oxides is highly desirable. In this study, epitaxial BaTiO3/La0.7Sr0.3MnO3 freestanding bilayer membranes are fabricated using pulsed laser epitaxy. The membrane displays ferroelectricity and ferromagnetism above room temperature accompanying the finite magnetoelectric coupling constant. This study reveals that a freestanding heterostructure can be used to manipulate the structural and emergent properties of the membrane. In the absence of the strain caused by the substrate, the change in orbital occupancy of the magnetic layer leads to the reorientation of the magnetic easy-axis, that is, perpendicular magnetic anisotropy. These results of designing multiferroic oxide membranes open new avenues to integrate such flexible membranes for electronic applications

    A microcrack propagation-based life prediction model for lithium-ion batteries with Ni-rich cathode materials

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    The formation and growth of solid electrolyte interphase (SEI) on the anode are key parameters governing battery life prediction models of lithium-ion batteries (LiBs). However, as conventional battery life prediction models do not reflect other degradation parameters such as crack formation and propagation in Ni-rich cathode materials, their accuracy is greatly reduced as the nickel content increases in layered oxide cathode materials. Herein, we propose an advanced prediction model that includes both crack propagation and SEI growth. The reliability of this microcrack propagation-based life prediction model is verified using experimental data of over 50 commercial 18650 LiB cells, which are tested under depths of discharge and current rates, from 500 to 5000 cycles. The proposed model predicts capacity retention values with less than 5 % error, even in practical operations of energy storage systems and electric vehicles, providing a standard solution for predicting the cycle life of LiBs with Ni-rich cathode materials. © 2022FALS

    Improving Bit-Error-Rate Performance Using Modulation Coding Techniques for Spin-Torque Transfer Magnetic Random Access Memory

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    In non-volatile random-access memory (RAM) technologies, the spin-torque transfer magnetic random-access memory (STT-MRAM) is a promising candidate. STT-MRAM has attracted attention owing to its advantages, such as a high density, high endurance, and high-speed writing/reading. Moreover, STT-MRAM is utilized to replace dynamic random-access memory (DRAM) in Internet of Things (IoT) and artificial intelligence (AI) applications. However, because the magnetic tunnel junction is used to write data, STT-MRAM must face process variation and thermal fluctuation problems. This causes errors in writing and reading processes. These errors are independent of each other. Therefore, to solve them and increase the reliability of STT-MRAM, the data are encoded before storage in STT-MRAM devices. In this study, we propose a method for designing codewords using modulation coding techniques. Our codewords increase the minimum Hamming distance and inheritance of the sparse code characteristic to exploit the asymmetric probability of the write errors. The simulation results show that our codewords can improve the bit error rate performance of STT-MRAM compared with previous works

    Self-assembled adipose-derived mesenchymal stem cells as an extracellular matrix component- and growth factor-enriched filler

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    The clinical application of mesenchymal stem cells (MSCs) is attracting attention due to their excellent safety, convenient acquisition, multipotency, and trophic activity. The clinical effectiveness of transplanted MSCs is well-known in regenerative and immunomodulatory medicine, but there is a demand for their improved viability and regenerative function after transplantation. In this study, we isolated MSCs from adipose tissue from three human donors and generated uniformly sized MSC spheroids (∼100 µm in diameter) called microblocks (MiBs) for dermal reconstitution. The viability and MSC marker expression of MSCs in MiBs were similar to those of monolayer MSCs. Compared with monolayer MSCs, MiBs produced more extracellular matrix (ECM) components, including type I collagen, fibronectin, and hyaluronic acid, and growth factors such as vascular endothelial growth factor and hepatocyte growth factor. Subcutaneously injected MiBs showed skin volume retaining capacity in mice. These results indicate that MiBs could be applied as regenerative medicine for skin conditions such as atrophic scar by having high ECM and bioactive factor expression

    Tandem Observations of Nighttime Mid-Latitude Topside Ionospheric Perturbations

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    Nighttime medium-scale traveling ionospheric disturbances (MSTIDs) have been generally observed by ground-based instruments. However, they provide 2-dimensional images over only a limited field of view and are not distributed globally. The ground-based observations reported that MSTID wavefronts exhibit backward-C shapes virtually straddling the dip equator. In situ plasma density measurements onboard individual satellites could overcome the limited coverage of ground-based MSTID observations. But, most of those spacecrafts could obtain only 1-dimensional profiles of plasma density, which leaves uncertain whether the observed perturbations generally have the characteristic directivity of MSTIDs. This paper addresses this knowledge gap by statistically investigating nighttime perturbations in the mid-latitude topside ionosphere observed by tandem satellites, Swarm A and C. We cross-correlate the plasma density profiles observed by Swarm A and C. The correlation coefficient tends to increase as the two spacecraft move closer, allowing us to derive the disturbances' directivity whenever the Swarm A and C observations are correlated significantly. The directivity statistics agree well with the backward-C shape. Furthermore, the wavefront directions have clear dependence on magnetic latitudes while they are not as well aligned with local time, which is also consistent with previous reports on nighttime MSTIDs using ground-based observations and computer simulations. Additionally, we demonstrate that the nighttime MSTIDs can increase the topside Rate Of Total electron content Index above Swarm. All the above-mentioned results support that the nighttime mid-latitude perturbations observed by Swarm can be identified as MSTIDs on the whole, which is the most important finding of this paper

    CWCL: Cross-Modal Transfer with Continuously Weighted Contrastive Loss

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    This paper considers contrastive training for cross-modal 0-shot transfer wherein a pre-trained model in one modality is used for representation learning in another domain using pairwise data. The learnt models in the latter domain can then be used for a diverse set of tasks in a zero-shot way, similar to ``Contrastive Language-Image Pre-training (CLIP)'' and ``Locked-image Tuning (LiT)'' that have recently gained considerable attention. Most existing works for cross-modal representation alignment (including CLIP and LiT) use the standard contrastive training objective, which employs sets of positive and negative examples to align similar and repel dissimilar training data samples. However, similarity amongst training examples has a more continuous nature, thus calling for a more `non-binary' treatment. To address this, we propose a novel loss function called Continuously Weighted Contrastive Loss (CWCL) that employs a continuous measure of similarity. With CWCL, we seek to align the embedding space of one modality with another. Owing to the continuous nature of similarity in the proposed loss function, these models outperform existing methods for 0-shot transfer across multiple models, datasets and modalities. Particularly, we consider the modality pairs of image-text and speech-text and our models achieve 5-8% (absolute) improvement over previous state-of-the-art methods in 0-shot image classification and 20-30% (absolute) improvement in 0-shot speech-to-intent classification and keyword classification.Comment: Accepted to Neural Information Processing Systems (NeurIPS) 2023 conferenc

    Lysosomal control of senescence and inflammation through cholesterol partitioning

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    Whereas cholesterol is vital for cell growth, proliferation, and remodeling, dysregulation of cholesterol metabolism is associated with multiple age-related pathologies. Here we show that senescent cells accumulate cholesterol in lysosomes to maintain the senescence-associated secretory phenotype (SASP). We find that induction of cellular senescence by diverse triggers enhances cellular cholesterol metabolism. Senescence is associated with the upregulation of the cholesterol exporter ABCA1, which is rerouted to the lysosome, where it moonlights as a cholesterol importer. Lysosomal cholesterol accumulation results in the formation of cholesterol-rich microdomains on the lysosomal limiting membrane enriched with the mammalian target of rapamycin complex 1 (mTORC1) scaffolding complex, thereby sustaining mTORC1 activity to support the SASP. We further show that pharmacological modulation of lysosomal cholesterol partitioning alters senescence-associated inflammation and in vivo senescence during osteoarthritis progression in male mice. Our study reveals a potential unifying theme for the role of cholesterol in the aging process through the regulation of senescence-associated inflammation. Senescenct cells are shown to accumulate cholesterol in lysosomes, which upregulates mTORC1 signaling, thereby supporting the senescence-associated secretory phenotype and promoting senescence-associated inflammation.11Nsciescopu

    Vutiglabridin Modulates Paraoxonase 1 and Ameliorates Diet-Induced Obesity in Hyperlipidemic Mice

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    Vutiglabridin is a clinical-stage synthetic small molecule that is being developed for the treatment of obesity and its target proteins have not been fully identified. Paraoxonase-1 (PON1) is an HDL-associated plasma enzyme that hydrolyzes diverse substrates including oxidized low-density lipoprotein (LDL). Furthermore, PON1 harbors anti-inflammatory and antioxidant capacities and has been implicated as a potential therapeutic target for treating various metabolic diseases. In this study, we performed a non-biased target deconvolution of vutiglabridin using Nematic Protein Organisation Technique (NPOT) and identified PON1 as an interacting protein. We examined this interaction in detail and demonstrate that vutiglabridin binds to PON1 with high affinity and protects PON1 against oxidative damage. Vutiglabridin treatment significantly increased plasma PON1 levels and enzyme activity but not PON1 mRNA in wild-type C57BL/6J mice, suggesting that vutiglabridin modulates PON1 post-transcriptionally. We further investigated the effects of vutiglabridin in obese and hyperlipidemic LDLR−/− mice and found that it significantly increases plasma PON1 levels, while decreasing body weight, total fat mass, and plasma cholesterol levels. Overall, our results demonstrate that PON1 is a direct, interacting target of vutiglabridin, and that the modulation of PON1 by vutiglabridin may provide benefits for the treatment of hyperlipidemia and obesity

    Implementation of ubiquitous chromatin opening elements as artificial integration sites for CRISPR/Cas9‐mediated knock‐in in mammalian cells

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    Abstract CRISPR/Cas9‐mediated targeted gene integration (TI) has been used to generate recombinant mammalian cell lines with predictable transgene expression. Identifying genomic hot spots that render high and stable transgene expression and knock‐in (KI) efficiency is critical for fully implementing TI‐mediated cell line development (CLD); however, such identification is cumbersome. In this study, we developed an artificial KI construct that can be used as a hot spot at different genomic loci. The ubiquitous chromatin opening element (UCOE) was employed because of its ability to open chromatin and enable stable and site‐independent transgene expression. UCOE KI cassettes were randomly integrated into CHO‐K1 and HEK293T cells, followed by TI of enhanced green fluorescent protein (EGFP) onto the artificial UCOE KI site. The CHO‐K1 random pool harboring 5′2.2A2UCOE‐CMV displayed a significant increase in EGFP expression level and KI efficiency compared with that of the control without UCOE. In addition, 5′2.2A2UCOE‐CMV showed improved Cas9 accessibility in the HEK293T genome, leading to an increase in indel frequency and homology‐independent KI. Overall, this assessment revealed the potential of UCOE KI constructs as artificial integration sites in streamlining the screening of high‐production targeted integrants by mitigating the selection of genomic hot spots