1,196 research outputs found

    Extending the depth of field in a compound-eye imaging system with super-resolution reconstruction

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    Optical device miniaturization is highly desirable in many applications. Direct down-scaling of traditional imaging system is one approach, but the extent to which it can be minimized is limited by the effect of diffraction. Compound-eye imaging system, which utilizes multiple microlenses in image capture is a promising alternative. In this paper, we explore the possibility of an incorporation of phase masks in such a system to extend the depth of field. Simulation experiments are conducted to verify the feasibility of the system. © 2006 IEEE.published_or_final_versio

    A total variation regularization based super-resolution reconstruction algorithm for digital video

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    Super-resolution (SR) reconstruction technique is capable of producing a high-resolution image from a sequence of low-resolution images. In this paper, we study an efficient SR algorithm for digital video. To effectively deal with the intractable problems in SR video reconstruction, such as inevitable motion estimation errors, noise, blurring, missing regions, and compression artifacts, the total variation (TV) regularization is employed in the reconstruction model. We use the fixed-point iteration method and preconditioning techniques to efficiently solve the associated nonlinear Euler-Lagrange equations of the corresponding variational problem in SR. The proposed algorithm has been tested in several cases of motion and degradation. It is also compared with the Laplacian regularization-based SR algorithm and other TV-based SR algorithms. Experimental results are presented to illustrate the effectiveness of the proposed algorithm.£.published_or_final_versio

    Reference-free detection of semiconductor assembly defect

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    This paper aims at developing a novel defect detection algorithm for the semiconductor assembly process by image analysis of a single captured image, without reference to another image during inspection. The integrated circuit (IC) pattern is usually periodic and regular. Therefore, we can implement a classification scheme whereby the regular pattern in the die image is classified as the acceptable circuit pattern and the die defect can be modeled as irregularity on the image. The detection of irregularity in image is thus equivalent to the detection of die defect. We propose a method where the defect detection algorithm first segments the die image into different regions according to the circuit pattern by a set of morphological segmentations with different structuring element sizes. Then, a feature vector, which consists of many image attributes, is calculated for each segmented region. Lastly, the defective region is extracted by the feature vector classification. © 2005 SPIE and IS&T.published_or_final_versio

    "Faith Maturity Scale" for Chinese: A Revision and Construct Validation

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    Using a large sample of Chinese Christians (n = 2,196), we examined the internal structure, reliability, and validity of the Faith Maturity Scale (FMS). Despite its being developed in North America, and for a mainline Protestant population, the FMS was shown to have validity among non-Western, non-mainline Protestants. There is convergent validity with self-reported religious practices and a belief measure of religiosity. Our analyses also confirmed good construct validity with the Big Five personality dimensions, social axioms, attributional style, and quality of life. FMS remained associated with religious practices and high quality of life after personality was statistically controlled. Findings supported that the Chinese version of the FMS assesses the same theoretical construct as does the original scale and that the distinction between the vertical and horizontal dimensions of faith maturity is meaningful. © 2011 Copyright Taylor and Francis Group, LLC.postprin

    Deletions within the azoospermia factor subregions of the Y chromosome in Hong Kong Chinese men with severe male-factor infertility: controlled clinical study.

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    OBJECTIVE: To determine the patterns and the prevalence of microdeletions in the azoospermia factor subregions of the Y chromosome in Hong Kong Chinese men with severe male-factor infertility. DESIGN: Controlled clinical study. SETTING: Reproductive centre of a university teaching hospital, Hong Kong. PARTICIPANTS: Fifty-eight men with severe male-factor infertility who participated in the in vitro fertilisation programme from May 1998 through March 1999, and 46 male volunteers with proven fertility. MAIN OUTCOME MEASURES: Polymerase chain reaction analysis of DNA from peripheral blood lymphocytes using six loci spanning the AZFa, AZFb, and AZFc subregions of the Y chromosome. RESULTS. No microdeletions were detected in the fertile controls or in patients with obstructive azoospermia. Deletions within the AZFc subregion were found in 9% (4/44) of men with non-obstructive azoospermia or severe oligospermia. Neither AZFa nor AZFb deletions were detected in any participants. CONCLUSION: Deletions within the azoospermia factor subregions of the Y chromosome are associated with severe male-factor infertility in Hong Kong Chinese men.published_or_final_versio

    Characteristics of transposable element exonization within human and mouse

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    Insertion of transposed elements within mammalian genes is thought to be an important contributor to mammalian evolution and speciation. Insertion of transposed elements into introns can lead to their activation as alternatively spliced cassette exons, an event called exonization. Elucidation of the evolutionary constraints that have shaped fixation of transposed elements within human and mouse protein coding genes and subsequent exonization is important for understanding of how the exonization process has affected transcriptome and proteome complexities. Here we show that exonization of transposed elements is biased towards the beginning of the coding sequence in both human and mouse genes. Analysis of single nucleotide polymorphisms (SNPs) revealed that exonization of transposed elements can be population-specific, implying that exonizations may enhance divergence and lead to speciation. SNP density analysis revealed differences between Alu and other transposed elements. Finally, we identified cases of primate-specific Alu elements that depend on RNA editing for their exonization. These results shed light on TE fixation and the exonization process within human and mouse genes.Comment: 11 pages, 4 figure

    PhOTO Zebrafish: A Transgenic Resource for In Vivo Lineage Tracing during Development and Regeneration

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    Background: Elucidating the complex cell dynamics (divisions, movement, morphological changes, etc.) underlying embryonic development and adult tissue regeneration requires an efficient means to track cells with high fidelity in space and time. To satisfy this criterion, we developed a transgenic zebrafish line, called PhOTO, that allows photoconvertible optical tracking of nuclear and membrane dynamics in vivo. Methodology: PhOTO zebrafish ubiquitously express targeted blue fluorescent protein (FP) Cerulean and photoconvertible FP Dendra2 fusions, allowing for instantaneous, precise targeting and tracking of any number of cells using Dendra2 photoconversion while simultaneously monitoring global cell behavior and morphology. Expression persists through adulthood, making the PhOTO zebrafish an excellent tool for studying tissue regeneration: after tail fin amputation and photoconversion of a ~100µm stripe along the cut area, marked differences seen in how cells contribute to the new tissue give detailed insight into the dynamic process of regeneration. Photoconverted cells that contributed to the regenerate were separated into three distinct populations corresponding to the extent of cell division 7 days after amputation, and a subset of cells that divided the least were organized into an evenly spaced, linear orientation along the length of the newly regenerating fin. Conclusions/Significance: PhOTO zebrafish have wide applicability for lineage tracing at the systems-level in the early embryo as well as in the adult, making them ideal candidate tools for future research in development, traumatic injury and regeneration, cancer progression, and stem cell behavior

    CRISPR-Cas9 screens in human cells and primary neurons identify modifiers of C9ORF72 dipeptide-repeat-protein toxicity.

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    Hexanucleotide-repeat expansions in the C9ORF72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD). The nucleotide-repeat expansions are translated into dipeptide-repeat (DPR) proteins, which are aggregation prone and may contribute to neurodegeneration. We used the CRISPR-Cas9 system to perform genome-wide gene-knockout screens for suppressors and enhancers of C9ORF72 DPR toxicity in human cells. We validated hits by performing secondary CRISPR-Cas9 screens in primary mouse neurons. We uncovered potent modifiers of DPR toxicity whose gene products function in nucleocytoplasmic transport, the endoplasmic reticulum (ER), proteasome, RNA-processing pathways, and chromatin modification. One modifier, TMX2, modulated the ER-stress signature elicited by C9ORF72 DPRs in neurons and improved survival of human induced motor neurons from patients with C9ORF72 ALS. Together, our results demonstrate the promise of CRISPR-Cas9 screens in defining mechanisms of neurodegenerative diseases

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Ergothioneine Biosynthesis and Functionality in the Opportunistic Fungal Pathogen, Aspergillus fumigatus.

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    Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a trimethylated and sulphurised histidine derivative which exhibits antioxidant properties. Here we report that deletion of Aspergillus fumigatus egtA (AFUA_2G15650), which encodes a trimodular enzyme, abrogated EGT biosynthesis in this opportunistic pathogen. EGT biosynthetic deficiency in A. fumigatus significantly reduced resistance to elevated H2O2 and menadione, respectively, impaired gliotoxin production and resulted in attenuated conidiation. Quantitative proteomic analysis revealed substantial proteomic remodelling in ΔegtA compared to wild-type under both basal and ROS conditions, whereby the abundance of 290 proteins was altered. Specifically, the reciprocal differential abundance of cystathionine γ-synthase and β-lyase, respectively, influenced cystathionine availability to effect EGT biosynthesis. A combined deficiency in EGT biosynthesis and the oxidative stress response regulator Yap1, which led to extreme oxidative stress susceptibility, decreased resistance to heavy metals and production of the extracellular siderophore triacetylfusarinine C and increased accumulation of the intracellular siderophore ferricrocin. EGT dissipated H2O2 in vitro, and elevated intracellular GSH levels accompanied abrogation of EGT biosynthesis. EGT deficiency only decreased resistance to high H2O2 levels which suggests functionality as an auxiliary antioxidant, required for growth at elevated oxidative stress conditions. Combined, these data reveal new interactions between cellular redox homeostasis, secondary metabolism and metal ion homeostasis
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