7,532 research outputs found

    Time-Interleaved Analog-to-Digital Converter (TIADC) Compensation Using Multichannel Filters

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    Published methods that employ a filter bank for compensating the timing and bandwidth mismatches of an M-channel time-interleaved analog-to-digital converter (TIADC) were developed based on the fact that each sub-ADC channel is a downsampled version of the analog input. The output of each sub-ADC is filtered in such a way that, when all the filter outputs are summed, the aliasing components are minimized. If each channel of the filter bank has N coefficients, the optimization of the coefficients requires computing the inverse of an MN times MN matrix if the weighted least squares (WLS) technique is used as the optimization tool. In this paper, we present a multichannel filtering approach for TIADC mismatch compensation. We apply the generalized sampling theorem to directly estimate the ideal output of each sub-ADC using the outputs of all the sub-ADCs. If the WLS technique is used as the optimization tool, the dimension of the matrix to be inversed is N times N. For the same number of coefficients (and also the same spurious component performance given sufficient arithmetic precision), our technique is computationally less complex and more robust than the filter-bank approach. If mixed integer linear programming is used as the optimization tool to produce filters with coefficient values that are integer powers of two, our technique produces a saving in computing resources by a factor of approximately (100.2N(M- 1)/(M-1) in the TIADC filter design.published_or_final_versio

    Flexible transistor active matrix array with all screen-printed electrodes

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    Flexible transistor active matrix array is fabricated on PEN substrate using all screen-printed gate, source and drain electrodes. Parylene-C and DNTT act as gate dielectric layer and semiconductor, respectively. The transistor possesses high mobility (0.33 cm2V-1 s-1), large on/off ratio (< 106) and low leakage current (10 pA). Active matrix array consists of 10×10 transistors were demonstrated. Transistors exhibited average mobility of 0.29 cm2V-1s-1 and on/off ratio larger than 104 in array form. In the transistor array, we achieve 75μm channel length and a size of 2 mm × 2 mm for each element in the array which indicates the current screen-printing method has large potential in large-area circuits and display applications. © 2013 SPIE.published_or_final_versio

    Angiopoietin-1 and keratinocyte growth factor restore the impaired alveolar fluid clearance induced by influenza H5N1 virus infection

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    Poster Session: Novel TherapeuticsBackground: Acute respiratory distress syndrome (ARDS) caused by high pathogenic avian influenza (HPAI) H5N1 virus infection has resulted in severe illness and high mortality rates among patients. Patients with ARDS are often characterized by impaired alveolar fluid clearance and alveolar edema. An understanding of the mechanism responsible for human alveolar edema will lead to the development of novel therapeutic treatments for ARDS patients. We hypothesized that the paracrine soluble factors angiopoietin-1 (Ang-1) and keratinocyte growth factor (KGF) can resolve alveolar fluid clearance by up-regulating the expression of major sodium and chloride transporters impaired by HPAI H5N1 virus infection. Materials and Methods: Human alveolar epithelial cells grown on transwell inserts were infected with HPAI H5N1 (A/HK/483/97) and low pathogenic avian influenza (LPAI) H1N1 (A/HK/54/98) viruses at MOI 0.1 or incubated with conditioned culture medium containing Ang-1 and/or KGF. At 24 and 48 h post-infection, the rate of alveolar fluid transport and protein permeability across the alveolar epithelium was measured. Protein expression of sodium and chloride transporters (Na-K-ATPase, CFTR, and epithelial sodium channel alpha subunit) was measured by qPCR, ELISA, and Western blot. Results: HPAI H5N1 (A/HK/483/97) virus infection significantly reduced net alveolar fluid transport and protein permeability when compared with H1N1 (A/HK/54/98) virus infection at 24 h post-infection and further reduced it at 48 h post-infection. This reduction in alveolar fluid clearance was associated with a substantial reduction in protein expression of Na-K-ATPase, CFTR, and epithelial sodium channel alpha subunit. The influenza virus–infected cells treated with Ang-1 and KGF restored the impaired alveolar edema fluid clearance and protein permeability after HPAI H5N1 virus infection. Furthermore, the paracrine soluble factors Ang-1 and KGF up-regulated the protein expression of the major sodium and chloride transporters resulting from the HPAI influenza virus infection. Conclusions: The paracrine soluble factors Ang-1 and KGF play an important role in maintaining human alveolar fluid clearance by up-regulating the sodium and chloride transporting systems in human alveolar epithelium. This study enriches the understanding of the development of ARDS in human H5N1 disease and may aid in the development of possible therapeutic applications.published_or_final_versio

    Spin-echo BOLD temporal dynamics in the rat superior colliculus and lateral geniculate nucleus

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    Session - fMRI Neuroscience Methods & Applications I: Computer 57 (Wednesday)INTRODUCTION: The superior colliculus (SC) and lateral geniculate nucleus (LGN) are important subcortical components of the visual system[1]. The majority of fMRI studies to date focus on higher visual processing centers in the cortex. fMRI studies in rats have examined visual responses in the subcortex using long stimulus duration block-design paradigms[2-4]. These studies focused on locating responsive regions and measuring differences in BOLD responses for different stimulation frequencies. Relatively little attention has been given to BOLD temporal dynamics in the rat subcortex. In this study, we apply …published_or_final_versionThe 19th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2011), Montreal, QC., 7-13 May 2011.In Proceedings of the 19th ISMRM, 2011, v. 19, p. 365

    Transcriptomic Responses Of Corpuscle Of Stannius Gland Of Japanese Eels (anguilla Japonica) To Changes In Water Salinity

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    Physiological studies of a unique endocrine gland in fish, named corpuscles of Stannius (CS), described a Ca2+-regulatory function for this gland mediated by stanniocalcin-1, a hypocalcemic polypeptide hormone. However, to date, the endocrine functions of the glands have not been completely elucidated. We hypothesized that other unidentified active principles in the glands are involved in the regulation of plasma ion (Na+, Ca2+) and/or blood pressure. In this study, transcriptome sequencing of CS glands was performed using Japanese eels (Anguilla japonica) adapted to freshwater (FW) or seawater (SW) to reveal the presence and differential expression of genes encoding proteins related to the ion-osmoregulatory and pressor functions. We acquired a total of 14.1 Mb and 12.1 Mb quality-trimmed reads from the CS glands collected from FW and SW adapted eels, respectively. The de novo assembly resulted in 9254 annotated genes. Among them, 475 genes were differentially expressed with 357 up- and 118 down-regulated in the SW group. Gene ontology analysis further demonstrated the presence of natriuresis and pressor related genes. In summary, ours is the first study using high-throughput sequencing to identify gene targets that could explain the physiological importance of the CS glands.published_or_final_versio

    Developing a platform of environmental omics for the green-lipped mussel Perna viridis

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    Session Track: Aquatic and terrestrial ecotoxicologyOral presentationConference Theme: Science across bridges, borders and boundariesThe green-lipped mussel Perna viridis is an important marine biomonitor species in pollution monitoring and ecotoxicological studies in Asia-Pacific region, and considered as a subtropical equivalent biomonitor of the temperate Mytilus species. However, the genomic information of P. viridis is still largely unexplored when compared with Mytilus species. This study aimed to establish a transcriptomic profile of P. viridis using the next generation sequencing technology and provide a good representative set of genomic information for elucidation of toxic mechanisms upon pollution stresses and identification of a suite of suitable biomarkers for monitoring marine pollution and environmental stresses. To obtain a wide spectrum of environmental-associated transcripts, adult mussels (4-5 cm shell length) were collected from different locations in Hong Kong and from those after 24-hour exposures to various challenges of physical stresses and chemical pollutants, so as to cover a wide range of stress-associated transcription patterns for future environmental studies. Two males and females from each location and from each treatment were chosen for obtaining the three target tissues (i.e., hepatopancreas, gill and adductor muscle). For each sex and each tissue type, a total RNA sample was extracted from pooled tissues from the field and laboratory treated mussels. The RNA sample was subjected to cDNA library construction, followed by the RNA-sequencing using a Solexa GAIIx (Illumina). Including the splicing variants, a de novo assembly of a total length of 295,064,579 base-pair (bp) contig was obtained, with 233,257 contigs assembled of an average size of 1264 bp. The 192,879 non-redundant assembled transcripts were blasted against the NCBI nr database and three molluscan EST databases, and resulted in 44,713 transcripts with at least a blast hit, and having a top match with the sequences from the Pacific oyster, Crassostrea gigas (27,651 transcripts). A total of 5,131 transcripts were assigned with KEGG annotation involving in 329 pathways. Based on multivariate statistical analysis, expression patterns of genes from stress associated responses and detoxification were strongly tissue-specific but the differences between genders were little. The anticipated genomic database generated from this study will further strengthen the role of P. viridis as a universal marine biomonitor in the Asia-Pacific region.published_or_final_versio
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