666 research outputs found

    Isolation of a transcriptionally active element of high copy number retrotransposons in sweetpotato genome

    Get PDF
    Many plant retrotransposons have been characterized, but only three families (Tnt1, Tto1 and Tos17) have been demonstrated to be transpositionally competent. We followed a novel approach that enabled us to identify an active element of the Ty1-copia retrotransposon family with estimated 400 copies in the sweetpotato genome. DNA sequences of Ty1 -copia reverse transcriptase (RTase) from the sweetpotato genome were analyzed, and a group of retrotransposon copies probably formed by recent transposition events was further analyzed. 3’RACE on callus cDNA amplified transcripts containing long terminal repeats (LTR) of this group. The sequence -specific amplification polymorphism (S-SAP) patterns of the LTR sequence in the genomic DNA were compared between a normal plant and callus lines derived from it. A callus -specific S-SAP product was found into which the retrotransposon detected by the 3’RACE had been transposed apparently during cell culture. We conclude that our approach provides an effective way to identify active elements of retrotransposons with high copy numbers.</p

    Metabolic design of Escherichia coli for muconic acid production

    Get PDF
    Adipic acid(AA) is a versatile bulk chemical to be used for raw materials such as nylon 6,6. Currently, AA biosynthesis from bio-resources have received a lot of attention in recent years as environment-friendly and renewable AA production process. Muconic acid(MA), also known as 2,4-hexadienedioic acid, is expected as a biosynthesis precursor of AA. There are Several studies on MA biosynthesis using Escherichia coli introduced foreign genes. In those studies, MA is synthesized from intermediate products of shikimate pathway. However, the production volume is not sufficient and it is a hindrance to industrialization. In this study, we aimed to the high efficiency biosynthesis of MA using metabolic designed Escherichia coli. First, we designed the metabolism to increase the accumulation of phosphoenolpyruvic acid (PEP), which is one of the starting materials of the shikimate pathway. Next, we determined the optimal MA synthetic pathway branched from the shikimate pathway. Specifically, we examined three types of MA production pathway with PEP accumulation strain as parent and selected the pathway with the highest MA production. Finally, we examined efficient production of MA using fusion proteins. Shikimate pathway protein and MA production pathway protein were combined to direct carbon flux into MA production

    Impact of feed water pH and membrane material on nanofiltration of perfluorohexanoic acid in aqueous

    Get PDF
    Nanofiltration was thought to be a good option for the recovery of perfluorohexanoic acid (PFHxA) from industrial wastewater. In this study, two commercially available nanofiltration (NF) membranes (NF 270 and NTR-7450) were tested to concentrate the PFHxA in aqueous solution. Filtration test was conducted in crossflow filtration mode. Membrane flux and PFHxA rejection rate were monitored throughout the filtration test. The impact of initial feed water pH on membrane performance was investigated. Results demonstrated that the two NF membranes showed different response to the change of initial feed water pH, which was caused by the intrinsic properties of membrane material. The flux performance of NF 270 was stable, while its rejection rate of PFHxA was very sensitive to the change of initial feed water pH. Opposite result was obtained with NTR-7450. It had a very good stability on rejection rate, while its flux was very sensitive to the change of initial feed water pH. The mechanisms behind these phenomena were also discussed. The results obtained in this study should be very useful for the process design in practical engineering

    Quantification of microplastic by particle size down to 1.1 μm in surface road dust in an urban city, Japan

    Get PDF
    The impact of microplastics (MPs, plastic particles ≤5 mm) on ecosystems is of great concern. Road surfaces represent a significant source of MPs where plastic fragments are physically and chemically reduced to MPs. However, the literature lacks information on fragmentation tendencies below 11 μm. This study aimed to characterize the occurrence of MPs in road dust in different size fractions down to 1.1 μm. Road dust was collected at five sites near a major road in Kusatsu city, Japan, and partitioned by size into 13 fractions (1.1–850 μm). The coarser fractions accounted for a greater proportion of the dust. The percentage of organic matter, determined by loss on ignition, increased as the fractions became finer. Pyrolysis-gas chromatography-mass spectrometry was used to quantify 12 types of polymers in each fraction. The dust was found to contain nine types of MP, namely, polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polystyrene (PS), styrene/butadiene rubber (SBR), acrylonitrile/butadiene/styrene resin (ABS), polycarbonate (PC), polymethylmethacrylate (PMMA), and polyamide 66 (PA66). The total MP concentration in road dust particles by particle size fraction (concentrationf) began to increase from the 125–250 μm fraction and remained elevated in finer fractions down to 1.1 μm, indicating that MPs in the road dust micronized to at least 1.1 μm. However, for individual polymer types, the tendency for concentrationf to increase or decrease with particle size fraction varied: the concentrationf of some polymers, such as PE and PVC, remained elevated in fractions down to 1.1 μm; the concentrationf of SBR, a rubber-MP, showed a stable or decreasing trend in fractions of 7.0–11 μm and finer. Particles of PE, PVC, and some other plastics might become increasingly finer, even down to 1.1 μm. Further research is needed to understand the comminution limits of these polymers under pertinent environmental conditions

    A unified origin for the 3D magnetism and superconductivity in Nax_xCoO2_2

    Full text link
    We analyze the origin of the three dimensional (3D) magnetism observed in nonhydrated Na-rich Nax_xCoO2_2 within an itinerant spin picture using a 3D Hubbard model. The origin is identified as the 3D nesting between the inner and outer portions of the Fermi surface, which arise due to the local minimum structure of the a1ga_{1g} band at the Γ\Gamma-A line. The calculated spin wave dispersion strikingly resembles the neutron scattering result. We argue that this 3D magnetism and the spin fluctuations responsible for superconductivity in the hydrated systems share essentially the same origin.Comment: 5pages, 6figure

    Ladder Siamese Network: a Method and Insights for Multi-level Self-Supervised Learning

    Full text link
    Siamese-network-based self-supervised learning (SSL) suffers from slow convergence and instability in training. To alleviate this, we propose a framework to exploit intermediate self-supervisions in each stage of deep nets, called the Ladder Siamese Network. Our self-supervised losses encourage the intermediate layers to be consistent with different data augmentations to single samples, which facilitates training progress and enhances the discriminative ability of the intermediate layers themselves. While some existing work has already utilized multi-level self supervisions in SSL, ours is different in that 1) we reveal its usefulness with non-contrastive Siamese frameworks in both theoretical and empirical viewpoints, and 2) ours improves image-level classification, instance-level detection, and pixel-level segmentation simultaneously. Experiments show that the proposed framework can improve BYOL baselines by 1.0% points in ImageNet linear classification, 1.2% points in COCO detection, and 3.1% points in PASCAL VOC segmentation. In comparison with the state-of-the-art methods, our Ladder-based model achieves competitive and balanced performances in all tested benchmarks without causing large degradation in one

    Leveraging Image-Text Similarity and Caption Modification for the DataComp Challenge: Filtering Track and BYOD Track

    Full text link
    Large web crawl datasets have already played an important role in learning multimodal features with high generalization capabilities. However, there are still very limited studies investigating the details or improvements of data design. Recently, a DataComp challenge has been designed to propose the best training data with the fixed models. This paper presents our solution to both filtering track and BYOD track of the DataComp challenge. Our solution adopts large multimodal models CLIP and BLIP-2 to filter and modify web crawl data, and utilize external datasets along with a bag of tricks to improve the data quality. Experiments show our solution significantly outperforms DataComp baselines (filtering track: 6.6% improvement, BYOD track: 48.5% improvement).Comment: Accepted at the ICCV 2023 Workshop on Towards the Next Generation of Computer Vision Datasets: DataComp Trac

    烏口突起骨端線離開の新分類:自験例9例と過去の論分のレビューから

    Get PDF
    Objectives and Design. Epiphyseal separation of the coracoid process (CP) rarely occurs in adolescents. In this retrospective case series, we reviewed the data of nine patients treated at our center and those of 28 patients reported in the literature. This injury can be classified into three types according to the injured area: Type I, base including the area above the glenoid; Type II, center including the coracoclavicular ligament (CCL); and Type III, tip with the short head of the biceps and coracobrachialis, as well as the pectoralis minor. Patients/Participants. A total of 37 patients were included in the analysis. Data on sex, age, cause and mechanism of injury, separation type, concomitant injury around the shoulder girdle, treatment, and functional outcomes were obtained. Main Outcome Measurements and Results. Type I is the most common type. The cause of injury and associated injury around the shoulder girdle were significantly different between Type I, II, and III fractures. The associated acromioclavicular (AC) dislocation and treatment were significantly different between Type I and III fractures. Our new classification system reflects the clinical features, imaging findings, and surgical management of epiphyseal separation of the CP. Type I and II fractures are mostly associated with AC dislocation and have an associated injury around the shoulder girdle. Type III fractures are typically caused by forceful resisted flexion of the arm and elbow. Although the latter are best managed surgically, whether conservative or surgical management is optimal for Type I and II fractures remains controversial. Conclusions. We noted some differences in the clinical characteristics depending on the location of injury; therefore, we aimed to examine these differences to develop a new system for classifying epiphyseal separation of the CP. This would increase the clinicians' awareness regarding this injury and lead to the development of an appropriate treatment.博士(医学)・甲第783号・令和3年3月15日Copyright © 2020 Takamitsu Mondori et al. This is an open access article distributed under the Creative Commons Attribution License(https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
    corecore