783 research outputs found

    Low-complexity face-assisted video coding

    Get PDF
    [[abstract]]This paper presents a novel face-assisted video coding scheme to enhance the visual quality of the face regions in video telephony applications. A skin-color based face detection and tracking scheme is proposed to locate the face regions in real-time. After classifying the macroblocks into the face and non-face regions, we present a dynamic distortion weighting adjustment (DDWA) scheme to drop the static non-face macroblocks, and the saved bits are used to compensate the face region by adjusting the distortion weighting of the face macroblocks. The quality of face regions will thus be enhanced. Moreover, the computation originally required for the skipped macroblocks can also be saved. The experimental results show that the proposed method can significantly improve the PSNR and the subjective quality of face regions, while the degradation introduced on the non-face areas is relatively insensitive to human perception. The proposed algorithm is fully compatible with the H.263 standard, and the low complexity feature makes it well suited to implement for real-time applications[[fileno]]2030144030041[[department]]電機工程學

    Realtime object extraction and tracking with an active camera using image mosaics

    Get PDF
    [[abstract]]Moving object extraction plays a key role in applications such as object-based videoconference, surveillance, and so on. The dimculties of moving object segmentation lie in the fact that physical objects are normally not homogeneous with to low-level features and it's usually tough to segment them accnrately and efficiently. Object segmentation based on prestored background information has proved to be effective and efficient in several applications such as videophone, video conferencing, and surveillance, etc. The previous works, however, were mainly concentrated on object segmentation with a static camera and in a stationary background. In this paper, we propose a robust and fast segmentation algorithm and a reliable tracking strategy without knowing the shape of the object in advance. The proposed system can real-time extract the foreground from the background and track the moving object with an active (pan-tilt) camera such that the moving object always stays around the center of images.[[fileno]]2030144030033[[department]]電機工程學

    Chlorophyll dephytylase 1 and chlorophyll synthase: a chlorophyll salvage pathway for the turnover of photosystems I and II

    Get PDF
    Chlorophyll (Chl) is made up of the tetrapyrrole chlorophyllide and phytol, a diterpenoid alcohol. The photosynthetic protein complexes utilize Chl for light harvesting to produce biochemical energy for plant development. However, excess light and adverse environmental conditions facilitate generation of reactive oxygen species, which damage photosystems I and II (PSI and PSII) and induce their turnover. During this process, Chl is released, and is thought to be recycled via dephytylation and rephytylation. We previously demonstrated that Chl recycling in Arabidopsis under heat stress is mediated by the enzymes chlorophyll dephytylase 1 (CLD1) and chlorophyll synthase (CHLG) using chlg and cld1 mutants. Here, we show that the mutants with high CLD1/CHLG ratio, by different combinations of chlg‐1 (a knock‐down mutant) and the hyperactive cld1‐1 alleles, develop necrotic leaves when grown under long‐ and short‐day, but not continuous light conditions, owing to the accumulation of chlorophyllide in the dark. Combination of chlg‐1 with cld1‐4 (a knock‐out mutant) leads to reduced chlorophyllide accumulation and necrosis. The operation of CLD1 and CHLG as a Chl salvage pathway was also explored in the context of Chl recycling during the turnover of Chl‐binding proteins of the two photosystems. CLD1 was found to interact with CHLG and the light‐harvesting complex‐like proteins OHP1 and LIL3, implying that auxiliary factors are required for this process.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Ministry of Science and Technology, Taiwan http://dx.doi.org/10.13039/501100004663Peer Reviewe

    Nitroprusside modulates pulmonary vein arrhythmogenic activity

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Pulmonary veins (PVs) are the most important sources of ectopic beats with the initiation of paroxysmal atrial fibrillation, or the foci of ectopic atrial tachycardia and focal atrial fibrillation. Elimination of nitric oxide (NO) enhances cardiac triggered activity, and NO can decrease PV arrhythmogensis through mechano-electrical feedback. However, it is not clear whether NO may have direct electrophysiological effects on PV cardiomyocytes. This study is aimed to study the effects of nitroprusside (NO donor), on the ionic currents and arrhythmogenic activity of single cardiomyocytes from the PVs.</p> <p>Methods</p> <p>Single PV cardiomyocytes were isolated from the canine PVs. The action potential and ionic currents were investigated in isolated single canine PV cardiomyocytes before and after sodium nitroprusside (80 μM,) using the whole-cell patch clamp technique.</p> <p>Results</p> <p>Nitroprusside decreased PV cardiomyocytes spontaneous beating rates from 1.7 ± 0.3 Hz to 0.5 ± 0.4 Hz in 9 cells (P < 0.05); suppressed delayed afterdepolarization in 4 (80%) of 5 PV cardiomyocytes. Nitroprusside inhibited L-type calcium currents, transient outward currents and transient inward current, but increased delayed rectified potassium currents.</p> <p>Conclusion</p> <p>Nitroprusside regulates the electrical activity of PV cardiomyocytes, which suggests that NO may play a role in PV arrhythmogenesis.</p

    Evolutionary conservation of DNA-contact residues in DNA-binding domains

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>DNA-binding proteins are of utmost importance to gene regulation. The identification of DNA-binding domains is useful for understanding the regulation mechanisms of DNA-binding proteins. In this study, we proposed a method to determine whether a domain or a protein can has DNA binding capability by considering evolutionary conservation of DNA-binding residues.</p> <p>Results</p> <p>Our method achieves high precision and recall for 66 families of DNA-binding domains, with a false positive rate less than 5% for 250 non-DNA-binding proteins. In addition, experimental results show that our method is able to identify the different DNA-binding behaviors of proteins in the same SCOP family based on the use of evolutionary conservation of DNA-contact residues.</p> <p>Conclusion</p> <p>This study shows the conservation of DNA-contact residues in DNA-binding domains. We conclude that the members in the same subfamily bind DNA specifically and the members in different subfamilies often recognize different DNA targets. Additionally, we observe the co-evolution of DNA-contact residues and interacting DNA base-pairs.</p

    Tet oncogene family member 2 gene alterations in childhood acute myeloid leukemia

    Get PDF
    Background/PurposeMutations in the tet oncogene family member 2 gene (TET2) are frequently found in adult patients with acute myeloid leukemia (AML). Reports of TET2 mutations in children are limited. We assessed the prevalence of TET2 mutations in Taiwanese children with AML and analyzed their prognosis.MethodsBetween 1997 and 2010, a total of 69 consecutive children with AML were enrolled at the National Taiwan University Hospital. The analysis for TET2 mutations was performed using direct sequencing. Clinical characteristics and overall survival (OS) were compared between patients with and without TET2 alterations.ResultsIntronic and missense mutations were identified. No nonsense or frameshift mutations were observed. Two putative disease-causing missense mutations (S609C and A1865G) were identified in one patient. We estimated the prevalence of TET2 mutations in the current patient population to be 1.4%. The most common polymorphism was I1762V (45%), followed by V218M (12%), P29R (6%), and F868L (6%). Patients with polymorphism I1762V had an increased 10-year survival rate compared with patients without I1762V (48.4% vs. 25.7%, p = 0.049) by Chi-square test; OS was not different when examined using the Kaplan–Meier method (p = 0.104).ConclusionThe prevalence of TET2 mutations in children with AML compared with adults with AML was lower and less complex. Patient prognosis associated with TET2 mutations in children requires further investigation

    Molecular serotyping of Haemophilus parasuis isolated from diseased pigs and the relationship between serovars and pathological patterns in Taiwan

    Get PDF
    Background Haemophilus parasuis is the etiological agent of Glässer’s disease, and causes severe economic losses in the swine industry. Serovar classification is intended as an indicator of virulence and pathotype and is also crucial for vaccination programs and vaccine development. According to a polysaccharide biosynthesis locus analysis, H. parasuis isolates could be classified by a molecular serotyping assay except serovars 5 and 12 detected by the same primer pair. The aim of this study was to identify H. parasuis isolates from diseased pigs in Taiwan by using a molecular serotyping assay and to analyze the relationship between serovars and pathological patterns. Methods From August 2013 to February 2017, a total of 133 isolates from 277 lesions on 155 diseased animals from 124 infected herds serotyped by multiplex PCR and analyzed with pathological data. Results The dominant serovars of H. parasuis in Taiwan were serovars 5/12 (37.6%), 4 (27.8%) and 13 (15%) followed by molecular serotyping non-typable (MSNT) isolates (13.5%). Nevertheless, the serovar-specific amplicons were not precisely the same sizes as previously indicated in the original publication, and MSNT isolates appeared with unexpected amplicons or lacked serovar-specific amplicons. Most H. parasuis isolates were isolated from nursery pigs infected with porcine reproductive and respiratory syndrome virus. The percentage of lung lesions (30.4%) showing H. parasuis infection was significantly higher than that of serosal lesions. Discussion Collectively, the distribution of serovars in Taiwan is similar to that found in other countries, but MSNT isolates remain due to genetic variations. Furthermore, pulmonary lesions may be optimum sites for H. parasuis isolation, the diagnosis of Glässer’s disease, and may also serve as points of origin for systemic H. parasuis infections in hosts

    (O,O′-Diethyl dithio­phosphato-κ2 S,S′)(hydridotripyrazol-1-ylborato-κ3 N 2,N 2′,N 2′′)(triphenyl­phosphine-κP)ruthenium(II)

    Get PDF
    Reaction of [Ru(Tp)Cl(PPh3)2] {where Tp is hydridotri­pyrazol­yl­borate, BH[C3H3N2)3)]} with NH4[S2P(OEt)2] in methanol afforded the title compound, [Ru(C9H10BN6)(C4H10O2PS2)(C18H15P)], in which the RuII ion is in a slightly disorted octa­hedral coordination environment. The [S2P(OEt)2]− ligand coordinates in a chelating mode with two similar Ru—S bond lengths and a slightly acute S—Ru—S angle. The atoms of both –OCH2CH3 groups of the diethyl dithio­phosphate ligand are disordered over two sites with approximate occupancies of 0.76 and 0.24
    corecore