4,740 research outputs found

    Transposon variants and their effects on gene expression in arabidopsis

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    Transposable elements (TEs) make up the majority of many plant genomes. Their transcription and transposition is controlled through siRNAs and epigenetic marks including DNA methylation. To dissect the interplay of siRNA–mediated regulation and TE evolution, and to examine how TE differences affect nearby gene expression, we investigated genome-wide differences in TEs, siRNAs, and gene expression among three Arabidopsis thaliana accessions. Both TE sequence polymorphisms and presence of linked TEs are positively correlated with intraspecific variation in gene expression. The expression of genes within 2 kb of conserved TEs is more stable than that of genes next to variant TEs harboring sequence polymorphisms. Polymorphism levels of TEs and closely linked adjacent genes are positively correlated as well. We also investigated the distribution of 24-nt-long siRNAs, which mediate TE repression. TEs targeted by uniquely mapping siRNAs are on average farther from coding genes, apparently because they more strongly suppress expression of adjacent genes. Furthermore, siRNAs, and especially uniquely mapping siRNAs, are enriched in TE regions missing in other accessions. Thus, targeting by uniquely mapping siRNAs appears to promote sequence deletions in TEs. Overall, our work indicates that siRNA–targeting of TEs may influence removal of sequences from the genome and hence evolution of gene expression in plants

    Development of novel antimiRzymes for targeted inhibition of miR-21 expression in solid cancer cells

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    MicroRNAs (miRNAs) are short non-coding RNAs that are involved in the regulation of gene expression. Previous reports showed an over-expression of miRNA-21 (miR-21) in various cancer cells, and its up-regulation is closely related to cancer initiation, proliferation and metastasis. In this work, we envisioned the development of novel antimiRzymes (anti-miRNA-DNAzyme) that are capable of selectively targeting and cleaving miR-21 and inhibit its expression in cancer cells using the DNAzyme technique. For this purpose, we have designed different antimiRzyme candidates by systematically targeting different regions of miR-21. Our results demonstrated that RNV541, a potential arm-loop-arm type antimiRzyme, was very efficient (90%) to suppress miR-21 expression in U87MG malignant glioblastoma cell line at 200 nM concentration. In addition, RNV541 also inhibited miR-21 expression (50%) in MDA-MB-231 breast cancer cell line. For targeted delivery, we conjugated RNV541 with a transferrin receptor (TfR) targeting aptamer for TfR-mediated cancer cell delivery. As expected, the developed chimeric structure efficiently delivered the antimiRzyme RNV541 into TfR positive glioblastoma cells. TfR aptamer-RNV541 chimeric construct showed 52% inhibition of miR-21 expression in U87MG glioblastoma cells at 2000 nM concentration, without using any transfection reagents, making it a highly desirable strategy to tackle miR-21 over-expressed malignant cancers. Although these are in vitro based observations, based on our results, we firmly believe that our findings could be beneficial towards the development of targeted cancer therapeutics where conventional therapies face several challenges

    Enhancing content-based recommendation with the task model of classication

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    Slower Speed and Stronger Coupling: Adaptive Mechanisms of Self-Organized Chaos Synchronization

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    We show that two initially weakly coupled chaotic systems can achieve self-organized synchronization by adaptively reducing their speed and/or enhancing the coupling strength. Explicit adaptive algorithms for speed-reduction and coupling-enhancement are provided. We apply these algorithms to the self-organized synchronization of two coupled Lorenz systems. It is found that after a long-time self-organized process, the two coupled chaotic systems can achieve synchronization with almost minimum required coupling-speed ratio.Comment: 4 pages, 5 figure

    Interactive user modeling for personalized access to museum collections : the Rijksmuseum case study

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    In this paper we present an approach for personalized access to museum collections. We use a RDF/OWL specification of the Rijksmuseum Amsterdam collections as a driver for an interactive dialog. The user gives his/her judgment on the artefacts, indicating likes or dislikes. The elicited user model is further used for generating recommendations of artefacts and topics. In this way we support exploration and discovery of information in museum collections. A user study provided insights in characteristics of our target user group, and showed how novice and expert users employ their background knowledge and implicit interest in order to elicit their art preference in the museum collections

    Selfoscillations of Suspended Carbon Nanotubes with a Deflection Sensitive Resistance under Voltage Bias

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    We theoretically investigate the electro-mechanics of a Suspended Carbon Nanotube with a Deflection Sensitive Resistance subjected to a homogeneous Magnetic Field and a constant Voltage Bias. We show that, (with the exception of a singular case), for a sufficiently high magnetic field the time-independent state of charge transport through the nanotube becomes unstable to selfexcitations of the mechanical vibration accompanied by oscialltions in the voltage drop and current across the nanotube.Comment: 4 pages, 1 figur

    Health-related quality of life and associated factors in patients with myocardial infarction after returning to work: A cross-sectional study

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    Background Return to work following myocardial infarction (MI) represents an important indicator of recovery. However, MI can cause patients to feel pressure, loneliness and inferiority during work and even detachment from employment after returning to work, which may affect their quality of life. The aims of this study were to identify the influencing factors of Health-related quality of life (HRQoL) in patients with MI after returning to work and explore the correlations between these factors and HRQoL. Method This was a cross-sectional study. All participants were recruited from tertiary hospitals in China from October 2017 to March 2018. The general data questionnaire, Short-Form Health Survey-8 (SF-8), Health Promoting Lifestyle ProfileII (HPLPII), Medical Coping Modes Questionnaire (MCMQ) and Social Supporting Rating Scale (SSRS) were used to assess 326 patients with myocardial infarction returned to work after discharge. Multiple linear regression analysis was performed to explore factors related to HRQoL in patients with MI after returning to work. Results The sample consisted of 326 patients. The mean total score of quality of life was 28.03 ± 2.554. According to the multiple linear regression analysis, next factors were associated with better HRQoL: younger age (B = − 0.354, P = 0.039), higher income (B = 0.513, P = 0.000), less co-morbidity (B = − 0.440, P = 0.000), the longer time taken to return to work (B = 0.235, P = 0.003), fewer stents installed (B = − 0.359, P = 0.003), participation in cardiac rehabilitation (CR) (B = − 1.777, P = 0.000), complete CR (B = − 1.409, P = 0.000), better health behaviors such as more health responsibility (B = 0.172, P = 0.000) and exercise (B = 0.165, P = 0.000), better nutrition (B = 0.178, P = 0.000) and self-realization (B = 0.165, P = 0.000), stress response (B = 0.172, P = 0.000), more social support such as more objective support (B = 0.175, P = 0.000), subjective support (B = 0.167, P = 0.000) and better utilization of social support (B = 0.189, P = 0.028), positive copping strategies such as more coping (B = 0.133, P = 0.000) and less yield (B = − 0.165, P = 0.000). Conclusions HRQoL of MI patients after returning to work is not satisfactory. Health behavior, coping strategies, social support are factors which can affect HRQoL. A comprehensive and targeted guide may be a way to improve HRQoL and to assist patients’ successful return to society

    Universal quantum gates based on a pair of orthogonal cyclic states: Application to NMR systems

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    We propose an experimentally feasible scheme to achieve quantum computation based on a pair of orthogonal cyclic states. In this scheme, quantum gates can be implemented based on the total phase accumulated in cyclic evolutions. In particular, geometric quantum computation may be achieved by eliminating the dynamic phase accumulated in the whole evolution. Therefore, both dynamic and geometric operations for quantum computation are workable in the present theory. Physical implementation of this set of gates is designed for NMR systems. Also interestingly, we show that a set of universal geometric quantum gates in NMR systems may be realized in one cycle by simply choosing specific parameters of the external rotating magnetic fields. In addition, we demonstrate explicitly a multiloop method to remove the dynamic phase in geometric quantum gates. Our results may provide useful information for the experimental implementation of quantum logical gates.Comment: 9 pages, language revised, the publication versio

    Synthesis and super-resolution imaging performance of a refractive-index-controllable microsphere superlens

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    Microspheres can function as optical superlenses for nanoscale super-resolution imaging. The imaging performance is mainly affected by the size and refractive index of the microsphere. Precise control of these parameters is a challenging task but of fundamental importance to the further development of the technique. In this study, we demonstrate for the first time a nanoparticle-hybrid suspension polymerization approach to chemically synthesize high-quality microspheres (ZrO2/polystyrene) with optical properties that are highly controllable. Microspheres of different sizes (d: 2�20 μm) and refractive indexes (np: 1.590�1.685) were synthesized and their super-resolution imaging performances were evaluated and compared. Our results show that continuously increasing the refractive index of microspheres can enhance the imaging resolution and quality. A 60 nm resolution has been obtained in the wide-field imaging mode and a 50 nm resolution has been obtained in the confocal mode imaging of semiconductor chip samples. The obtained 50�60 nm resolutions have significantly gone beyond the conventional 200 nm resolution limit for visible light optical microscopes; the super-resolution mechanism has been discussed. The synthesized microsphere superlenses may find applications in many other areas as well, including nanolithography, nano-sensing, nano-diagnosis, nano-spectroscopy and ultra-high density optical data storage

    Adaptation step-by-step : challenges for real-time spatial personalization

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    In this paper we outline challenges for user modeling and personalization with spatial information. To illustrate those challenges we use a use case with a real-time routing system that implements a mobile museum guide for providing personalized tours tailored to the user position inside the museum and her interests. In this scenario we combine on the one hand (1) interactive discovery of user's interests applied for semantic recommendations of artworks and art-related topics, and on the other hand (2) dynamic step-by-step adaptation of a user's route through a museum based on her current position and changing interests. For this, the existing CHIP mobile museum guide was extended with a routing mechanism based on the SWI-Prolog Space package
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