790 research outputs found

    A Unitary Weights Based One-Iteration Quantum Perceptron Algorithm for Non-Ideal Training Sets

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    In order to solve the problem of non-ideal training sets (i.e., the less-complete or over-complete sets) and implement one-iteration learning, a novel efficient quantum perceptron algorithm based on unitary weights is proposed, where the singular value decomposition of the total weight matrix from the training set is calculated to make the weight matrix to be unitary. The example validation of quantum gates {H, S, T, CNOT, Toffoli, Fredkin} shows that our algorithm can accurately implement arbitrary quantum gates within one iteration. The performance comparison between our algorithm and other quantum perceptron algorithms demonstrates the advantages of our algorithm in terms of applicability, accuracy, and availability. For further validating the applicability of our algorithm, a quantum composite gate which consists of several basic quantum gates is also illustrated.Comment: 12 pages, 5 figure

    Fabrication and ultraviolet photoresponse characteristics of ordered SnOx (x ≈ 0.87, 1.45, 2) nanopore films

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    Based on the porous anodic aluminum oxide templates, ordered SnOx nanopore films (approximately 150 nm thickness) with different x (x ≈ 0.87, 1.45, 2) have been successfully fabricated by direct current magnetron sputtering and oxidizing annealing. Due to the high specific surface area, this ordered nanopore films exhibit a great improvement in recovery time compared to thin films for ultraviolet (UV) detection. Especially, the ordered SnOx nanopore films with lower x reveal higher UV light sensitivity and shorter current recovery time, which was explained by the higher concentration of the oxygen vacancies in this SnOx films. This work presents a potential candidate material for UV light detector

    Constitutive and Inducible Expression of the rRNA Methylase Gene erm(B) in Campylobacter

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    Macrolides are the antimicrobials of choice for treating human campylobacteriosis. The recent emergence of erm(B) in Campylobacter bacteria threatens the utility of this class of antibiotics. Here we report the constitutive and inducible expression of erm(B) in Campylobacter isolates derived from diarrheal patients and food-producing animals. Constitutive expression of erm(B) was associated with insertion and deletion in the regulatory region of the gene, providing the first documentation of the differential expression of erm(B) in Campylobacter bacteria

    Evolutionary Insights into the Organization of Chromatin Structure and Landscape of Transcriptional Regulation in Plants

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    Development of complex traits necessitates the functioning and coordination of intricate regulatory networks involving multiple genes. Understanding three-dimensional (3D) chromatin structure can facilitate insight into the regulation of gene expression by regulatory elements. This potential, of visualizing the role of chromatin organization in the evolution and function of regulatory elements, remains largely unexplored. Here we describe new perspectives that arise from the dual considerations of sequence variation of regulatory elements and chromatin structure, with a special focus on whole-genome doubling, or polyploidy. We underscore the significance of hierarchical chromatin organization in gene regulation during evolution. In addition, we describe strategies for exploring chromatin organization in future investigations of regulatory evolution in plants, enabling insights into the evolutionary influence of regulatory elements on gene expression and hence phenotypes.This is a manuscript of an article published as Long, Yuexuan, Jonathan F. Wendel, Xianlong Zhang, and Maojun Wang. "Evolutionary insights into the organization of chromatin structure and landscape of transcriptional regulation in plants." Trends in Plant Science 29, no. 6 (2024): 638-649. https://doi.org/10.1016/j.tplants.2023.11.00

    Emergence of Multidrug-Resistant Campylobacter Species Isolates with a Horizontally Acquired rRNA Methylase

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    Antibiotic-resistant Campylobacter constitutes a serious threat to public health, and resistance to macrolides is of particular concern, as this class of antibiotics is the drug of choice for clinical therapy of campylobacteriosis. Very recently, a horizontally transferrable macrolide resistance mediated by the rRNA methylase gene erm(B) was reported in a Campylobacter coli isolate, but little is known about the dissemination of erm(B) among Campylobacter isolates and the association of erm(B)-carrying isolates with clinical disease. To address this question and facilitate the control of antibiotic-resistant Campylobacter, we determined the distribution of erm(B) in 1,554 C. coli and Campylobacter jejuni isolates derived from food-producing animals and clinically confirmed human diarrheal cases. The results revealed that 58 of the examined isolates harbored erm(B) and exhibited high-level resistance to macrolides, and most were recent isolates, derived in 2011-2012. In addition, the erm(B)-positive isolates were all resistant to fluoroquinolones, another clinically important antibiotic used for treating campylobacteriosis. The erm(B) gene is found to be associated with chromosomal multidrug resistance genomic islands (MDRGIs) of Gram-positive origin or with plasmids of various sizes. All MDRGIs were transferrable to macrolide-susceptible C. jejuni by natural transformation under laboratory conditions. Molecular typing of the erm(B)-carrying isolates by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) identified diverse genotypes and outbreak-associated diarrheal isolates. Molecular typing also suggested zoonotic transmission of erm(B)-positive Campylobacter. These findings reveal an emerging and alarming trend of dissemination of erm(B) and MDRGIs in Campylobacter and underscore the need for heightened efforts to control their further spread

    Transgenic tobacco plant overexpressing ginkgo dihydroflavonol 4-reductase gene GbDFR6 exhibits multiple developmental defects

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    Dihydroflavonol Q 4-reductase (DFR), a key enzyme in the flavonoid biosynthetic pathway in plants, significantly influences plant survival. However, the roles of DFR in the regulation of plant development are largely unknown. In the present study, phenotypes of transgenic tobacco plants overexpressing the Ginkgo biloba DFR gene, GbDFR6, were investigated. Transgenic tobacco seedlings exhibited relatively low fresh weights, long primary roots, decreased lateral root numbers, and impaired root gravitropic responses when compared to wild-type tobacco plants. Adult transgenic tobacco plants exhibited a considerably high percentage of wrinkled leaves when compared to the wild-type tobacco plants. In addition to the auxin-related phenotypic changes, transgenic tobacco plants exhibited delayed flowering phenotypes under short-day conditions. Gene expression analysis revealed that the delayed flowering in transgenic tobacco plants was caused by the low expression levels of NtFT4. Finally, variations in anthocyanin and flavonoid contents in transgenic tobacco plants were evaluated. The results revealed that the levels of most anthocyanins identified in transgenic tobacco leaves increased. Specifically, cyanidin-3,5-O-diglucoside content increased by 9.8-fold in transgenic tobacco plants when compared to the wild-type tobacco plants. Pelargonidin-3-O-(coumaryl)-glucoside was only detected in transgenic tobacco plants. Regarding flavonoid compounds, one flavonoid compound (epicatechin gallate) was upregulated, whereas seven flavonoid compounds (Tamarixetin-3-O-rutinoside; Sexangularetin-3-O-glucoside-7-O-rhamnoside; Kaempferol-3-O-neohesperidoside; Engeletin; 2’-Hydoxy,5-methoxyGenistein-O-rhamnosyl-glucoside; Diosmetin; Hispidulin) were downregulated in both transgenic tobacco leaves and roots. The results indicate novel and multiple roles of GbDFR6 in ginkgo and provide a valuable method to produce a late flowering tobacco variety in tobacco industry
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