27 research outputs found

    High-Power Diode-Pumped Short Pulse Lasers Based on Yb:KGW Crystals for Industrial Applications

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    A diode-pumped, ultrafast Yb:KYW laser system utilizing chirped-pulse amplification (CPA) in a dual-slab regenerative amplifier (RA) with spectral shaping of seeding pulse from a master oscillator (MO) has been developed. A train of compressed pulses with pulse length of 181 fs, repetition rate up to 500 kHz, and average power exceeding 15 W after compression and pulse picker was achieved

    Complete Genome Sequences of Three Historically Important, Spatiotemporally Distinct, and Genetically Divergent Strains of Zika Virus: MR-766, P6-740, and PRVABC-59

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    Here, we report the 10,807-nucleotide-long consensus RNA genome sequences of three spatiotemporally distinct and genetically divergent Zika virus strains, with the functionality of their genomic sequences substantiated by reverse genetics: MR-766 (African lineage, Uganda, 1947), P6-740 (Asian lineage, Malaysia, 1966), and PRVABC-59 (Asian lineage-derived American strain, Puerto Rico, 2015)

    Development of a highly sensitive real-time one step RT-PCR combined complementary locked primer technology and conjugated minor groove binder probe

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    <p>Abstract</p> <p>Background</p> <p>Enterovirus (EV) infections are commonly associated with encephalitis and meningitis. Detection of enteroviral RNA in clinical specimens has been demonstrated to improve the management of patients, by ruling out other causes of disease.</p> <p>Method</p> <p>To develop a sensitive and reliable assay for routine laboratory diagnosis, we developed a real-time one step reverse transcription polymerase chain reaction (RT-PCR) assay with minor groove binder probes and primers modified with complementary locked primer technology (TMC-PCR). We checked the sensitivity of the developed assay by comparing it to a previously published TaqMan probe real-time one-step RT-PCR (TTN-PCR) procedure using enteroviral isolates, Enterovirus Proficiency panels from Quality Control on Molecular Diagnostics (QCMD-2007), and clinical specimens from patients with suspected EV infections.</p> <p>Results</p> <p>One hundred clinical specimens from 158 suspected viral meningitis cases were determined to be positive by the TMC-PCR assay (63.29%), whereas only 60 were found to be positive by the TTN-PCR assay (37.97%). The positive and negative agreements between the TMC-PCR and TTN-PCR assays were 100% and 59.2%, respectively.</p> <p>Conclusion</p> <p>This data suggest that the TMC-PCR assay may be suitable for routine diagnostic screening from patient suspected EV infection.</p

    Polarization-sensitive optical frequency domain imaging based on unpolarized light

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    Polarization-sensitive optical coherence tomography (PS-OCT) is an augmented form of OCT, providing 3D images of both tissue structure and polarization properties. We developed a new method of polarization-sensitive optical frequency domain imaging (PS-OFDI), which is based on a wavelength-swept source. In this method the sample was illuminated with unpolarized light, which was composed of two orthogonal polarization states (i.e., separated by 180° in the Poincaré sphere) that are uncorrelated to each other. Reflection of these polarization states from within the sample was detected simultaneously and independently using a frequency multiplexing scheme. This simultaneous sample probing with two polarization states enabled determination of the depth-resolved Jones matrices of the sample. Polarization properties of the sample were obtained by analyzing the sample Jones matrices through eigenvector decomposition. The new PS-OFDI system ran at 31K wavelength-scans/s with 3072 pixels per wavelength-scan, and was tested by imaging a polarizer and several birefringent tissues such as chicken muscle and human skin. Lastly the new PS-OFDI was applied to imaging two cancer animal models: a mouse model by injecting cancer cells and a hamster cheek pouch model. These animal model studies demonstrated the significant differences in tissue polarization properties between cancer and normal tissues in vivo. © 2011 Optical Society of America

    Effects of Land-Use Characteristics on Transport Mode Choices by Purpose of Travel in Seoul, South Korea, Based on Spatial Regression Analysis

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    The objective of this study was to identify the effects of land-use characteristics on the transport mode choices of people according to their purpose of travel. Land-use characteristics consisting of variables associated with density, diversity and accessibility were selected as independent variables. The volume of traffic entering each administrative neighborhood was extracted to establish travel data as the dependent variable. We compared and analyzed the results derived from ordinary least squares (OLS) analysis and spatial regression (SR) analysis. The results showed that the explanatory power of the SR model was higher than that of the OLS model. The results in this study reveal that the effects of land-use characteristics on travel show clear differences according to the transport mode, more so than according to the purpose of travel. Moreover, the results showed that an increase in the level of variables associated with density does not always facilitate the use of non-motorized or public transit modes, nor does it always deter the use of personal motorized modes. The findings in this study are significant in a knowledge-sharing context, as they present the effects of land-use characteristics on the volume of traffic in high-density cities, using Seoul as a case study

    Effects of Land-Use Characteristics on Transport Mode Choices by Purpose of Travel in Seoul, South Korea, Based on Spatial Regression Analysis

    No full text
    The objective of this study was to identify the effects of land-use characteristics on the transport mode choices of people according to their purpose of travel. Land-use characteristics consisting of variables associated with density, diversity and accessibility were selected as independent variables. The volume of traffic entering each administrative neighborhood was extracted to establish travel data as the dependent variable. We compared and analyzed the results derived from ordinary least squares (OLS) analysis and spatial regression (SR) analysis. The results showed that the explanatory power of the SR model was higher than that of the OLS model. The results in this study reveal that the effects of land-use characteristics on travel show clear differences according to the transport mode, more so than according to the purpose of travel. Moreover, the results showed that an increase in the level of variables associated with density does not always facilitate the use of non-motorized or public transit modes, nor does it always deter the use of personal motorized modes. The findings in this study are significant in a knowledge-sharing context, as they present the effects of land-use characteristics on the volume of traffic in high-density cities, using Seoul as a case study

    T-L Plane Based Real-Time Scheduling Using Dynamic Power Management

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    Current Status, Challenges, Policies, and Bioethics of Biobanks

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    Many biobanks were established as biorepositories for biomedical research, and a number of biobanks were founded in the 1990s. The main aim of the biobank is to store and to maintain biomaterials for studying chronic disease, identifying risk factors of specific diseases, and applying personalized drug therapies. This report provides a review of biobanks, including Korean biobanks and an analysis of sample volumes, regulations, policies, and ethical issues of the biobank. Until now, the top 6 countries according to the number of large-scale biobanks are the United Kingdom, United States, Sweden, France, the Netherlands, and Italy, and there is one major National Biobank of Korea (NBK) and 17 regional biobanks in Korea. Many countries have regulations and guidelines for the biobanks, and the importance of good management of biobanks is increasing. Meanwhile, according to a first survey of 456 biobank managers in the United States, biobankers are concerned with the underuse of the samples in their repositories, which need to be advertised for researchers. Korea Biobank Network (KBN) project phase II (2013-2015) was also planned for the promotion to use biospecimens in the KBN. The KBN is continuously introducing for researchers to use biospecimens in the biobank. An accreditation process can also be introduced for biobanks to harmonize collections and encourage use of biospecimens in the biobanks. KBN is preparing an on-line application system for the distribution of biospecimens and a biobank accreditation program and is trying to harmonize the biobanks

    Label-free neuroimaging in vivo using synchronous angular scanning microscopy with single-scattering accumulation algorithm

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    © 2019, The Author(s).Label-free in vivo imaging is crucial for elucidating the underlying mechanisms of many important biological systems in their most native states. However, the applicability of existing modalities has been limited to either superficial layers or early developmental stages due to tissue turbidity. Here, we report a synchronous angular scanning microscope for the rapid interferometric recording of the time-gated reflection matrix, which is a unique matrix characterizing full light-specimen interaction. By applying single scattering accumulation algorithm to the recorded matrix, we removed both high-order sample-induced aberrations and multiple scattering noise with the effective aberration correction speed of 10,000 modes/s. We demonstrated in vivo imaging of whole neural network throughout the hindbrain of the larval zebrafish at a matured stage where physical dissection used to be required for conventional imaging. Our method will expand the scope of applications for optical imaging, where fully non-invasive interrogation of living specimens is critica
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