111 research outputs found
Identification of cDNA Encoding a Serine Protease Homologous to Human Complement C1r Precursor from Grafted Mouse Skin
We isolated a cDNA clone from grafted mouse skin that encodes a serine protease homologous to human C1r. The C1r protease is involved in the activation of the first component of the classical pathway in the complement system. In order to identify novel transcripts whose expression is regulated in grafted mouse skin, we first perfomed differential display reverse transcription polymerase chain reaction analysis and obtained 18 partial cDNA clones whose protein products are likely to play an important role in allograft rejection. One of these showed significant sequence homology with human complement C1r precursor. The other clones displayed no homology to any known sequences, however. Northern blot analysis demonstrated that the level of this transcript was upregulated in day 8 postgrafted skin. The full-length cDNA 2121 nucleotides in length obtained from screening a mouse skin cDNA library contained a single open reading frame encoding 707 amino acid residues with a calculated molecular weight of 80,732โDa. Its deduced amino acid sequence revealed an 81% identity and 89% similarity to the human C1r counterpart. In particular, mouse C1r contained His501, Asp559, and Ser656, which were conserved among this group of serine proteases. This protein was thus designated as mouse C1r. We have expressed a truncated fragment of C1r protein without the N-terminal hydrophobic sequence in Escherichia coli and generated a polyclonal antibody against it. Subsequent immunohistochemical analysis confirmed that mouse C1r was significantly expressed 8โd after the skin graft in both allografted and autografted skins, compared with normal skins. These collective data suggest that a component of the complement system, C1r, might contribute to the graft versus host immune responses in mice
Optical Measurement of Neural Activity Using Surface Plasmon Resonance
We demonstrate that surface plasmon resonance (SPR) is applicable to the optical detection of neural signals.
A low-noise SPR sensor was developed as a label- and artifact-free method for the extracellular recording
of neural activity. The optical responses obtained from a rat sciatic nerve were highly correlated with
simultaneously recorded electrical responses. Additional studies with stimulation intensity and lidocaine
further confirmed that the optically measured signals originated from neural activities.The authors acknowledge the support of the Nano-
Bioelectronics and Systems Research Center of Seoul
National University, which is an Engineering Research
Center sponsored by the Korean Science and
Engineering Foundation (R11-2000-075-01001-1).
The authors also thank Hyung Chul Shin and Woo
Taek Oh for their helpful advice and Inter-university
Semiconductor Research Center for providing a laboratory
space
Avian influenza virus transmission is suppressed in chickens fed Lactobacillus paracasei expressing the 3D8 single-chain variable fragment protein
The 3D8 single-chain variable fragment (scFv) is a mini-antibody sequence with independent nuclease activity that shows antiviral effects against all types of viruses in chickens and mice. In this study, chickens were treated daily with an oral dose of 109 CFU Lactobacillus paracasei (L. paracasei) expressing either a secreted or anchored 3D8 scFv for three weeks. After L. paracasei administration, the chickens were challenged with avian influenza virus (AIV). From each experimental group, three chickens were directly infected with 100 ยตL of 107.5 EID50/mL H9N2 AIV and seven chickens were indirectly challenged through contact transmission. oropharyngeal and cloacal swab samples were collected at 3, 5, 7, and 9 days post-inoculation (dpi) from AIV-challenged chickens, AIV Shedding titres were measured by quantitative real-time PCR. Contact transmission in the chickens that were fed 3D8 scFv-secreting L. paracasei showed a significant reduction in viral shedding when compared with other groups. These results suggest that L. paracasei secreting 3D8 provides a basis for the development of ingestible antiviral probiotics with activity against AIV
DESIGN FOR A SIMPLIFIED COCHLEAR IMPLANT SYSTEM
This work was supported in part by the Korea Science and Engineering Foundation (KOSEF) through the Nano Bioelectronics and Systems Research Center (NBS-ERC) of Seoul National University (#R11-2000-075-01001-0) and in part by the Nurobiosys Corporation.
Electrode development was conducted in collaboration with the Epstein Laboratory at the University of California, San Francisco with support from NIH contracts #NO1-DC-2-1006 and NO1-DC-3-1006
Clinical Features of Re-Emerging Hepatitis A: An Analysis of Patients Hospitalized during an Urban Epidemic in Korea
From April 2008 to November 2008, many cases of hepatitis A were reported in Seoul and Gyeonggi Province in Korea. Furthermore, the rate of severe or fulminant hepatitis have significantly increased during the latest epidemic (13.4% vs. 5.2%, p=0.044). Therefore, widespread use of vaccine is warranted to reduce the burden of hepatitis A in Korea
Prevalence and Clinical Features of Detrusor Underactivity among Elderly with Lower Urinary Tract Symptoms: A Comparison between Men and Women
A Low-Power Analog Processor-in-Memory-Based Convolutional Neural Network for Biosensor Applications
This paper presents an on-chip implementation of an analog processor-in-memory (PIM)-based convolutional neural network (CNN) in a biosensor. The operator was designed with low power to implement CNN as an on-chip device on the biosensor, which consists of plates of 32 × 32 material. In this paper, 10T SRAM-based analog PIM, which performs multiple and average (MAV) operations with multiplication and accumulation (MAC), is used as a filter to implement CNN at low power. PIM proceeds with MAV operations, with feature extraction as a filter, using an analog method. To prepare the input feature, an input matrix is formed by scanning a 32 × 32 biosensor based on a digital controller operating at 32 MHz frequency. Memory reuse techniques were applied to the analog SRAM filter, which is the core of low power implementation, and in order to accurately grasp the MAC operational efficiency and classification, we modeled and trained numerous input features based on biosignal data, confirming the classification. When the learned weight data was input, 19 mW of power was consumed during analog-based MAC operation. The implementation showed an energy efficiency of 5.38 TOPS/W and was differentiated through the implementation of 8 bits of high resolution in the 180 nm CMOS process
Profile effect on the feasibility of extinction-based localized surface plasmon resonance biosensors with metallic nanowires
We investigate the effect of the cross-sectional profile of an array of metallic nanowires on the feasibility
of a localized surface plasmon resonance (LSPR) biosensor. Calculations were performed using rigorous
coupled-wave analysis with an emphasis on the extinction properties of the LSPR structure. The results
indicate that the nanowire structure, particularly that of a T-profile, delivers an extremely linear sensing
performance over a wide range of the target refractive index with much enhanced sensitivity. The
extinction-based LSPR structure also involves a relatively large dimension and thus is expected to
provide a feasible biosensor using current semiconductor technology.This work was supported by the Science Research Center
and Engineering Research Center program of the
Ministry of Science and Technology of the Korea Science
and Engineering Foundation (KOSEF) (R11-2000-075-
01001-1). D. Kim acknowledges the support by KOSEF
through the National Core Research Center for Nanomedical
Technology (R15-2004-024-00000-0) and by the
Korea Research Foundation Grant funded by the Korean
government (MOEHRD) under KRF-2005-205-D00051
Impact of the Surface Fluctuation of a Nanowire-Based Surface Plasmon Resonance Biosensor on the Sensitivity Enhancement
Effect of the nanowire cross-section on the sensitivity enhancement of localized surface plasmon resonance biosensors
In this study, localized surface plasmon resonance (SPR) biosensors with gold nanowires regularly patterned on a gold
film are considered for sensitivity enhancement. The theoretical investigation was conducted using rigorous coupled
wave analysis (RCWA) in terms of various design metrics, such as the resonance angle shift, the SPR curve angular
width (SPR CAW), and the minimum reflectance at resonance (MRR). Especially, when LSP modes couple resonantly,
broad SPR CAW and shallow MRR as well as a large shift of the resonance angle can be observed due to absorptive
damping and localized coupling. The results show that, in general, nanowires of a T-profile present more effective
sensitivity enhancement than an inverse T-profile. The sensitivity enhancement mediated by the presence of nanowires
has been clarified qualitatively based on the dispersion relation between metal film involving nanowires and surrounding
dielectric medium. Moreover, optimal design parameters of nanowires are determined based on quantitative metrics that
measure the sensor performance and the fabrication reliability.This work was supported by the SRC/ERC program of MOST/KOSEF (R11-2000-075-01001-1). D. Kim acknowledges
the support by KOSEF through National Core Research Center for Nanomedical Technology (R15-2004-024-00000-0)
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