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  • 1
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    Global shape mimicry of tRNA within a viral internal ribosome entry site mediates translational reading frame selection (2015)
    National Academy of Sciences
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    Publikationsdatum: 2015-11-09
    Beschreibung: The dicistrovirus intergenic region internal ribosome entry site (IRES) adopts a triple-pseudoknotted RNA structure and occupies the core ribosomal E, P, and A sites to directly recruit the ribosome and initiate translation at a non-AUG codon. A subset of dicistrovirus IRESs directs translation in the 0 and +1 frames to produce the viral structural proteins and a +1 overlapping open reading frame called ORFx, respectively. Here we show that specific mutations of two unpaired adenosines located at the core of the three-helical junction of the honey bee dicistrovirusIsraeli acute paralysis virus(IAPV) IRES PKI domain can uncouple 0 and +1 frame translation, suggesting that the structure adopts distinct conformations that contribute to 0 or +1 frame translation. Using a reconstituted translation system, we show that ribosomes assembled on mutant IRESs that direct exclusive 0 or +1 frame translation lack reading frame fidelity. Finally, a nuclear magnetic resonance/small-angle X-ray scattering hybrid approach reveals that the PKI domain of the IAPV IRES adopts an RNA structure that resembles a complete tRNA. The tRNA shape-mimicry enables the viral IRES to gain access to the ribosome tRNA-binding sites and form intermolecular contacts with the ribosome that are necessary for initiating IRES translation in a specific reading frame.
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Publiziert von National Academy of Sciences
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
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    Key role of soluble epoxide hydrolase in the neurodevelopmental disorders of offspring after maternal immune activation (2019)
    National Academy of Sciences
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    Publikationsdatum: 2019-03-19
    Beschreibung: Maternal infection during pregnancy increases risk of neurodevelopmental disorders such as schizophrenia and autism spectrum disorder (ASD) in offspring. In rodents, maternal immune activation (MIA) yields offspring with schizophrenia- and ASD-like behavioral abnormalities. Soluble epoxide hydrolase (sEH) plays a key role in inflammation associated with neurodevelopmental disorders. Here we found higher levels of sEH in the prefrontal cortex (PFC) of juvenile offspring after MIA. Oxylipin analysis showed decreased levels of epoxy fatty acids in the PFC of juvenile offspring after MIA, supporting increased activity of sEH in the PFC of juvenile offspring. Furthermore, expression of sEH (orEPHX2) mRNA in induced pluripotent stem cell-derived neurospheres from schizophrenia patients with the 22q11.2 deletion was higher than that of healthy controls. Moreover, the expression ofEPHX2mRNA in postmortem brain samples (Brodmann area 9 and 40) from ASD patients was higher than that of controls. Treatment with 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl)urea (TPPU), a potent sEH inhibitor, in juvenile offspring from prenatal day (P) 28 to P56 could prevent cognitive deficits and loss of parvalbumin (PV) immunoreactivity in the medial PFC of adult offspring after MIA. In addition, dosing of TPPU to pregnant mothers from E5 to P21 could prevent cognitive deficits, and social interaction deficits and PV immunoreactivity in the medial prefrontal cortex of juvenile offspring after MIA. These findings suggest that increased activity of sEH in the PFC plays a key role in the etiology of neurodevelopmental disorders in offspring after MIA. Therefore, sEH represents a promising prophylactic or therapeutic target for neurodevelopmental disorders in offspring after MIA.
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Publiziert von National Academy of Sciences
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
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    Gene deficiency and pharmacological inhibition of soluble epoxide hydrolase confers resilience to repeated social defeat stress (2016)
    National Academy of Sciences
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    Publikationsdatum: 2016-03-14
    Beschreibung: Depression is a severe and chronic psychiatric disease, affecting 350 million subjects worldwide. Although multiple antidepressants have been used in the treatment of depressive symptoms, their beneficial effects are limited. The soluble epoxide hydrolase (sEH) plays a key role in the inflammation that is involved in depression. Thus, we examined here the role of sEH in depression. In both inflammation and social defeat stress models of depression, a potent sEH inhibitor, TPPU, displayed rapid antidepressant effects. Expression of sEH protein in the brain from chronically stressed (susceptible) mice was higher than of control mice. Furthermore, expression of sEH protein in postmortem brain samples of patients with psychiatric diseases, including depression, bipolar disorder, and schizophrenia, was higher than controls. This finding suggests that increased sEH levels might be involved in the pathogenesis of certain psychiatric diseases. In support of this hypothesis, pretreatment with TPPU prevented the onset of depression-like behaviors after inflammation or repeated social defeat stress. Moreover, sEH KO mice did not show depression-like behavior after repeated social defeat stress, suggesting stress resilience. The sEH KO mice showed increased brain-derived neurotrophic factor (BDNF) and phosphorylation of its receptor TrkB in the prefrontal cortex, hippocampus, but not nucleus accumbens, suggesting that increased BDNF-TrkB signaling in the prefrontal cortex and hippocampus confer stress resilience. All of these findings suggest that sEH plays a key role in the pathophysiology of depression, and that epoxy fatty acids, their mimics, as well as sEH inhibitors could be potential therapeutic or prophylactic drugs for depression.
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Publiziert von National Academy of Sciences
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
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    Soluble epoxide hydrolase plays a key role in the pathogenesis of Parkinson’s disease (2018)
    National Academy of Sciences
    Details
    Publikationsdatum: 2018-05-07
    Beschreibung: Parkinson’s disease (PD) is characterized as a chronic and progressive neurodegenerative disorder, and the deposition of specific protein aggregates of α-synuclein, termed Lewy bodies, is evident in multiple brain regions of PD patients. Although there are several available medications to treat PD symptoms, these medications do not prevent the progression of the disease. Soluble epoxide hydrolase (sEH) plays a key role in inflammation associated with the pathogenesis of PD. Here we found that MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced neurotoxicity in the mouse striatum was attenuated by subsequent repeated administration of TPPU, a potent sEH inhibitor. Furthermore, deletion of the sEH gene protected against MPTP-induced neurotoxicity, while overexpression of sEH in the striatum significantly enhanced MPTP-induced neurotoxicity. Moreover, the expression of the sEH protein in the striatum from MPTP-treated mice or postmortem brain samples from patients with dementia of Lewy bodies (DLB) was significantly higher compared with control groups. Interestingly, there was a positive correlation between sEH expression and phosphorylation of α-synuclein in the striatum. Oxylipin analysis showed decreased levels of 8,9-epoxy-5Z,11Z,14Z-eicosatrienoic acid in the striatum of MPTP-treated mice, suggesting increased activity of sEH in this region. Interestingly, the expression of sEH mRNA in human PARK2 iPSC-derived neurons was higher than that of healthy control. Treatment with TPPU protected against apoptosis in human PARK2 iPSC-derived dopaminergic neurons. These findings suggest that increased activity of sEH in the striatum plays a key role in the pathogenesis of neurodegenerative disorders such as PD and DLB. Therefore, sEH may represent a promising therapeutic target for α-synuclein–related neurodegenerative disorders.
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Publiziert von National Academy of Sciences
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
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    Energies, Vol. 12, Pages 9: How Elastic Demand Affects Bidding Strategy in Electricity Market: An Auction Approach (2018)
    MDPI
    In: Energies
    Details
    Publikationsdatum: 2018
    Beschreibung: The deepening of electricity reform results in increasingly frequent auctions and the surge of generators, making it difficult to analyze generators’ behaviors. With the difficulties to find analytical market equilibriums, approximate equilibriums were obtained instead in previous studies by market simulations, where in some cases the results are strictly bound to the initial estimations and the results are chaotic. In this paper, a multi-unit power bidding model is proposed to reveal the bidding mechanism under clearing pricing rules by employing an auction approach, for which initial estimations are non-essential. Normalized bidding price is introduced to construct generators’ price-related bidding strategy. Nash equilibriums are derived depending on the marginal cost and the winning probability which are computed from bidding quantity, transmission cost and demand distribution. Furthermore, we propose a comparative analysis to explore the impact of uncertain elastic demand on the performance of the electricity market. The result indicates that, there exists market power among generators, which lead to social welfare decreases even under competitive conditions but elastic demand is an effective way to restrain generators’ market power. The feasibility of the models is verified by a case study. Our work provides decision support for generators and a direction for improving market efficiency.
    Digitale ISSN: 1996-1073
    Thema: Energietechnik
    Publiziert von MDPI
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
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    Analysis of the Metals in Soil-Water Interface in a Manganese Mine (2015)
    Hindawi
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    Publikationsdatum: 2015-06-18
    Beschreibung: In order to reveal the influence of the metals of soil-water interface in a manganese mine (Xiangtan, China), on local water environment, there are six kinds of metals (Mn, Ni, Cu, Zn, Cd, and Pb) characterized by measuring their concentration, correlation, source, and special distribution using principal component analysis, single factor, and Nemero comprehensive pollution index. The results showed that the corresponding average concentration was 0.3358, 0.045, 0.0105, 0.0148, 0.0067, and 0.0389 mg/L. The logarithmic concentration of Mn, Zn, and Pb was normal distribution. The correlation coefficients (between Mn and Pb, Mn and Zn, Mn and Ni, Cu and Zn, Cu and Pb, and Zn and Cd) were found to range from 0.5 to 0.6, and those between Cu and Ni and Cu and Cd were below 0.3. It was found that Zn and Mn pollution were caused primarily by ore mining, mineral waste transportation, tailing slag, and smelting plants, while Cu and Ni mainly originate from the mining industry activities and the traffic transportation in the mining area. In addition, the Cd was considered to be produced primarily from the agricultural or anthropogenic activities. The pollution indexes indicated that metal pollution degree was different in soil-water interface streams as listed in increasing order of pollution level as Zn 〉 Ni 〉 Cu 〉 Pb 〉 Mn 〉 Cd. For all of the pollution of the soil-water interface streams, there was moderate metal pollution but along the eastern mine area the pollution seemed to get more serious. There was only a small amount of soil-water interface streams not contaminated by the metals.
    Print ISSN: 2090-8865
    Digitale ISSN: 2090-8873
    Thema: Chemie und Pharmazie
    Publiziert von Hindawi
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
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    Inventory Model with Partial Backordering When Backordered Customers Delay Purchase after Stockout-Restoration (2016)
    Hindawi
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    Publikationsdatum: 2016-02-11
    Beschreibung: Many inventory models with partial backordering assume that the backordered demand must be filled instantly after stockout restoration. In practice, however, the backordered customers may successively revisit the store because of the purchase delay behavior, producing a limited backorder demand rate and resulting in an extra inventory holding cost. Hence, in this paper we formulate the inventory model with partial backordering considering the purchase delay of the backordered customers and assuming that the backorder demand rate is proportional to the remaining backordered demand. Particularly, we model the problem by introducing a new inventory cost component of holding the backordered items, which has not been considered in the existing models. We propose an algorithm with a two-layer structure based on Lipschitz Optimization (LO) to minimize the total inventory cost. Numerical experiments show that the proposed algorithm outperforms two benchmarks in both optimality and efficiency. We also observe that the earlier the backordered customer revisits the store, the smaller the inventory cost and the fill rate are, but the longer the order cycle is. In addition, if the backordered customers revisit the store without too much delay, the basic EOQ with partial backordering approximates our model very well.
    Print ISSN: 1024-123X
    Digitale ISSN: 1563-5147
    Thema: Mathematik , Technik allgemein
    Publiziert von Hindawi
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
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    Remote Sensing, Vol. 10, Pages 682: Infrared Image Enhancement Using Adaptive Histogram Partition and Brightness Correction (2018)
    MDPI Publishing
    Details
    Publikationsdatum: 2018-04-28
    Beschreibung: Remote Sensing, Vol. 10, Pages 682: Infrared Image Enhancement Using Adaptive Histogram Partition and Brightness Correction Remote Sensing doi: 10.3390/rs10050682 Authors: Minjie Wan Guohua Gu Weixian Qian Kan Ren Qian Chen Xavier Maldague Infrared image enhancement is a crucial pre-processing technique in intelligent urban surveillance systems for Smart City applications. Existing grayscale mapping-based algorithms always suffer from over-enhancement of the background, noise amplification, and brightness distortion. To cope with these problems, an infrared image enhancement method based on adaptive histogram partition and brightness correction is proposed. First, the grayscale histogram is adaptively segmented into several sub-histograms by a locally weighted scatter plot smoothing algorithm and local minima examination. Then, the fore-and background sub-histograms are distinguished according to a proposed metric called grayscale density. The foreground sub-histograms are equalized using a local contrast weighted distribution for the purpose of enhancing the local details, while the background sub-histograms maintain the corresponding proportions of the whole dynamic range in order to avoid over-enhancement. Meanwhile, a visual correction factor considering the property of human vision is designed to reduce the effect of noise during the procedure of grayscale re-mapping. Lastly, particle swarm optimization is used to correct the mean brightness of the output by virtue of a reference image. Both qualitative and quantitative evaluations implemented on real infrared images demonstrate the superiority of our method when compared with other conventional methods.
    Digitale ISSN: 2072-4292
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geographie
    Publiziert von MDPI Publishing
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
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    Remote Sensing, Vol. 10, Pages 510: Total Variation Regularization Term-Based Low-Rank and Sparse Matrix Representation Model for Infrared Moving Target Tracking (2018)
    MDPI Publishing
    Details
    Publikationsdatum: 2018-03-25
    Beschreibung: Remote Sensing, Vol. 10, Pages 510: Total Variation Regularization Term-Based Low-Rank and Sparse Matrix Representation Model for Infrared Moving Target Tracking Remote Sensing doi: 10.3390/rs10040510 Authors: Minjie Wan Guohua Gu Weixian Qian Kan Ren Qian Chen Hai Zhang Xavier Maldague Infrared moving target tracking plays a fundamental role in many burgeoning research areas of Smart City. Challenges in developing a suitable tracker for infrared images are particularly caused by pose variation, occlusion, and noise. In order to overcome these adverse interferences, a total variation regularization term-based low-rank and sparse matrix representation (TV-LRSMR) model is designed in order to exploit a robust infrared moving target tracker in this paper. First of all, the observation matrix that is derived from the infrared sequence is decomposed into a low-rank target matrix and a sparse occlusion matrix. For the purpose of preventing the noise pixel from being separated into the occlusion term, a total variation regularization term is proposed to further constrain the occlusion matrix. Then an alternating algorithm combing principal component analysis and accelerated proximal gradient methods is employed to separately optimize the two matrices. For long-term tracking, the presented algorithm is implemented using a Bayesien state inference under the particle filtering framework along with a dynamic model update mechanism. Both qualitative and quantitative experiments that were examined on real infrared video sequences verify that our algorithm outperforms other state-of-the-art methods in terms of precision rate and success rate.
    Digitale ISSN: 2072-4292
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geographie
    Publiziert von MDPI Publishing
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
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    Remote Sensing, Vol. 10, Pages 1039: A Level Set Method for Infrared Image Segmentation Using Global and Local Information (2018)
    MDPI Publishing
    Details
    Publikationsdatum: 2018-07-03
    Beschreibung: Remote Sensing, Vol. 10, Pages 1039: A Level Set Method for Infrared Image Segmentation Using Global and Local Information Remote Sensing doi: 10.3390/rs10071039 Authors: Minjie Wan Guohua Gu Jianhong Sun Weixian Qian Kan Ren Qian Chen Xavier Maldague Infrared image segmentation plays a significant role in many burgeoning applications of remote sensing, such as environmental monitoring, traffic surveillance, air navigation and so on. However, the precision is limited due to the blurred edge, low contrast and intensity inhomogeneity caused by infrared imaging. To overcome these challenges, a level set method using global and local information is proposed in this paper. In our method, a hybrid signed pressure function is constructed by fusing a global term and a local term adaptively. The global term is represented by the global average intensity, which effectively accelerates the evolution when the evolving curve is far away from the object. The local term is represented by a multi-feature-based signed driving force, which accurately guides the curve to approach the real boundary when it is near the object. Then, the two terms are integrated via an adaptive weight matrix calculated based on the range value of each pixel. Under the framework of geodesic active contour model, a new level set formula is obtained by substituting the proposed signed pressure function for the edge stopping function. In addition, a Gaussian convolution is applied to regularize the level set function for the purpose of avoiding the computationally expensive re-initialization. By iteration, the object of interest can be segmented when the level set function converges. Both qualitative and quantitative experiments verify that our method outperforms other state-of-the-art level set methods in terms of accuracy and robustness with the initial contour being set randomly.
    Digitale ISSN: 2072-4292
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geographie
    Publiziert von MDPI Publishing
    Standort Signatur Erwartet Verfügbarkeit
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