62 research outputs found

    A low-complexity and efficient encoder rate control solution for distributed residual video coding.

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    Existing encoder rate control (ERC) solutions have two technical limitations that prevent them from being widely used in real-world applications. One is that encoder side information (ESI) is required to be generated which increases the complexity at the encoder. The other is that rate estimation is performed at bit plane level which incurs computation overheads and latency when many bit planes exist. To achieve a low-complexity encoder, we propose a new ERC solution that combines an efficient encoder block mode decision (EBMD) for the distributed residual video coding (DRVC). The main contributions of this paper are as follows: 1) ESI is not required as our ERC is based on the analysis of the statistical characteristics of the decoder side information (DSI); 2) a simple EBMD is introduced which only employs the values of residual pixels at the encoder to classify blocks into Intra mode, Skip mode, and WZ mode; 3) an ERC solution using pseudo-random sequence scrambling is proposed to estimate rates for all WZ blocks at frame level instead of at bit plane level, i.e., only one rate is estimated; and 4) a quantization-index estimation algorithm (QIEA) is proposed to solve the problem of rate underestimation. The simulation results show that the proposed solution is not only low complex but also efficient in both the block mode decision and the rate estimation. Also, as compared to DISCOVER system and the state-of-the-art ERC solution, our solution demonstrates a competitive rate-distortion(RD)performance. Due to maintain the low-complexity nature of the encoder and have good RD performance, we believe that our ERC solution is promising in practice

    A simple encoder scheme for distributed residual video coding.

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    Rate-Distortion (RD) performance of Distributed Video Coding (DVC) is considerably less than that of conventional predictive video coding. In order to reduce the performance gap, many methods and techniques have been proposed to improve the coding efficiency of DVC with increased system complexity, especially techniques employed at the encoder such as encoder mode decisions, optimal quantization, hash methods etc., no doubt increase the complexity of the encoder. However, low complexity encoder is a widely desired feature of DVC. In order to improve the coding efficiency while maintaining low complexity encoder, this paper focuses on Distributed Residual Video Coding (DRVC) architecture and proposes a simple encoder scheme. The main contributions of this paper are as follows: 1) propose a bit plane block based method combined with bit plane re-arrangement to improve the dependency between source and Side Information (SI), and meanwhile, to reduce the amount of data to be channel encoded 2) present a simple iterative dead-zone quantizer with 3 levels in order to adjust quantization from coarse to fine. The simulation results show that the proposed scheme outperforms DISCOVER scheme for low to medium motion video sequences in terms of RD performance, and maintains a low complexity encoder at the same time

    Mutation screening of the SLC26A4 gene in a cohort of 192 Chinese patients with congenital hypothyroidism

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    ABSTRACT Objective: Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods: Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by nextgeneration sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results: Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions: The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH. Arch Endocrinol Metab. 2016;60(4):323-

    Current situation and related factors of occupational stress of employees of a petrochemical enterprise

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    BackgroundOccupational stress has become one of the main factors affecting people's physical and mental health, and there are many sources of occupational stress in petrochemical enterprises. ObjectiveTo evaluate the current situation of occupational stress and its related factors among employees in a petrochemical enterprise, and to provide a scientific basis for reduing the risk of occupational stress among employees in petrochemical enterprises. MethodsIn June 2022, a cross-sectional questionnaire survey was conducted in a petrochemical enterprise in Hainan, including a general information questionnaire for basic information, the Effort-Reward Imbalance (ERI) for occupational stress, and the Pittsburgh Sleep Quality Index (PSQI) for sleep quality. Chi-square test was used to compare differences in positive occupational stress by demographic characteristics, occupational characteristics, behavior, and occupational disease hazards. Logistic regression was employed to evaluate factors associated with occupational stress. ResultsOf the 1129 questionnaire distributed, a total of 999 valid questionnaire were returned,with a valid recovery rate of 88.5%. The positive rate of occupational stress among employees in the petrochemical enterprise was 29.5%. There were statistically significant differences in the positive rate of occupational stress among the employees grouped by gender, age, marital status, body mass index (BMI), monthly income, length of service, smoking, weekly working hours, type of work, working mode, sleep quality, noise exposure, and high temperature exposure (P<0.05). In terms of positive occupational stress among subcategories: workers being male (vs. female), working >40 h per week (vs. ≤40 h per week), regular day shift (vs. shift work), smoking (vs. not smoking), with exposure to noise and heat (vs. without such exposure), and having poor sleep quality (vs. good sleep quality) reported higher positive occupational stress rates (P<0.05). The results of pairwise comparison showed that the positive rate of occupational stress in divorced (50.0%) or married (32.0%) workers was higher than that in single (27.1%) workers, and higher in operation workers (30.6%) than in other types of work (20.5%) (P<0.05). The trend chi-square results showed that the positive rate of occupational stress increased linearly with the increase of age, length of service, BMI, or monthly income (P<0.05). The results of logistic regression analysis after adjustment showed that workers who worked >40 h a week had a higher risk of occupational stress than those who worked ≤40 h a week, and the OR (95%CI) was 1.909 (1.135, 3.211); the workers of other types of work had a lower risk of reporting occupational stress than operation workers, and the OR (95%CI) was 0.513 (0.272, 0.968); the workers with noise exposure had a higher risk of occupational stress than the workers without, and the OR (95%CI) was 2.457 (1.070, 5.642). ConclusionThe positive rate of occupational stress among employees in this petrochemical enterprise is high. Among them, operators, working hours per week>40 h, and noise exposure may increase the incidence of occupational stress. The enterprise should actively take measures to reduce the occurrence of occupational stress among employees

    Mutation screening of the SLC26A4 gene in a cohort of 192 Chinese patients with congenital hypothyroidism

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    ABSTRACT Objective: Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods: Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by next-generation sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results: Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions: The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH

    Antagonist Effect of Triptolide on AKT Activation by Truncated Retinoid X Receptor-alpha

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    Background: Retinoid X receptor-alpha (RXR alpha) is a key member of the nuclear receptor superfamily. We recently demonstrated that proteolytic cleavage of RXR alpha resulted in production of a truncated product, tRXR alpha, which promotes cancer cell survival by activating phosphatidylinositol-3-OH kinase (PI3K)/AKT pathway. However, how the tRXR alpha-mediated signaling pathway in cancer cells is regulated remains elusive. Methodology/Principal Findings: We screened a natural product library for tRXR alpha targeting leads and identified that triptolide, an active component isolated from traditional Chinese herb Trypterygium wilfordii Hook F, could modulate tRXR alpha-mediated cancer cell survival pathway in vitro and in animals. Our results reveal that triptolide strongly induces cancer cell apoptosis dependent on intracellular tRXR alpha expression levels, demonstrating that tRXR alpha serves as an important intracellular target of triptolide. We show that triptolide selectively induces tRXR alpha degradation and inhibits tRXR alpha-dependent AKT activity without affecting the full-length RXR alpha. Interestingly, such effects of triptolide are due to its activation of p38. Although triptolide also activates Erk1/2 and MAPK pathways, the effects of triptolide on tRXR alpha degradation and AKT activity are only reversed by p38 siRNA and p38 inhibitor. In addition, the p38 inhibitor potently inhibits tRXR alpha interaction with p85 alpha leading to AKT inactivation. Our results demonstrate an interesting novel signaling interplay between p38 and AKT through tRXR alpha mediation. We finally show that targeting tRXR alpha by triptolide strongly activates TNF alpha death signaling and enhances the anticancer activity of other chemotherapies Conclusions/Significance: Our results identify triptolide as a new xenobiotic regulator of the tRXR alpha-dependent survival pathway and provide new insight into the mechanism by which triptolide acts to induce apoptosis of cancer cells. Triptolide represents one of the most promising therapeutic leads of natural products of traditional Chinese medicine with unfortunate side-effects. Our findings will offer new strategies to develop improved triptolide analogs for cancer therapy.National Natural Science Foundation of China [NSFC: 30971445, 90913015, 91129302]; NSFC/Hong Kong Research Grants Council [NSFC/RGC: 30931160431/N_HKU 735/09]; Natural Science Foundation of Fujian Province [2009J01198

    Molecular evolution of Adh and LEAFY and the phylogenetic utility of their introns in Pyrus (Rosaceae)

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    <p>Abstract</p> <p>Background</p> <p>The genus <it>Pyrus </it>belongs to the tribe Pyreae (the former subfamily Maloideae) of the family Rosaceae, and includes one of the most important commercial fruit crops, pear. The phylogeny of <it>Pyrus </it>has not been definitively reconstructed. In our previous efforts, the internal transcribed spacer region (ITS) revealed a poorly resolved phylogeny due to non-concerted evolution of nrDNA arrays. Therefore, introns of low copy nuclear genes (LCNG) are explored here for improved resolution. However, paralogs and lineage sorting are still two challenges for applying LCNGs in phylogenetic studies, and at least two independent nuclear loci should be compared. In this work the second intron of <it>LEAFY </it>and the alcohol dehydrogenase gene (<it>Adh</it>) were selected to investigate their molecular evolution and phylogenetic utility.</p> <p>Results</p> <p>DNA sequence analyses revealed a complex ortholog and paralog structure of <it>Adh </it>genes in <it>Pyrus </it>and <it>Malus</it>, the pears and apples. Comparisons between sequences from RT-PCR and genomic PCR indicate that some <it>Adh </it>homologs are putatively nonfunctional. A partial region of <it>Adh1 </it>was sequenced for 18 <it>Pyrus </it>species and three subparalogs representing <it>Adh1-1 </it>were identified. These led to poorly resolved phylogenies due to low sequence divergence and the inclusion of putative recombinants. For the second intron of <it>LEAFY</it>, multiple inparalogs were discovered for both <it>LFY1int2 </it>and <it>LFY2int2</it>. <it>LFY1int2 </it>is inadequate for phylogenetic analysis due to lineage sorting of two inparalogs. <it>LFY2int2-N</it>, however, showed a relatively high sequence divergence and led to the best-resolved phylogeny. This study documents the coexistence of outparalogs and inparalogs, and lineage sorting of these paralogs and orthologous copies. It reveals putative recombinants that can lead to incorrect phylogenetic inferences, and presents an improved phylogenetic resolution of <it>Pyrus </it>using <it>LFY2int2-N</it>.</p> <p>Conclusions</p> <p>Our study represents the first phylogenetic analyses based on LCNGs in <it>Pyrus</it>. Ancient and recent duplications lead to a complex structure of <it>Adh </it>outparalogs and inparalogs in <it>Pyrus </it>and <it>Malus</it>, resulting in neofunctionalization, nonfunctionalization and possible subfunctionalization. Among all investigated orthologs, <it>LFY2int2-N </it>is the best nuclear marker for phylogenetic reconstruction of <it>Pyrus </it>due to suitable sequence divergence and the absence of lineage sorting.</p
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