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3,251 results on '"double-short"'

65. Synthesis, gene-silencing activity and nuclease resistance of 3'-3'-linked double short hairpin RNA

Author

Haruna Naruoka, Hirofumi Masuda, Takeshi Wada, Kazuchika Takagaki, Junichi Yano, Naoki Watanabe, and Seigo Nagata

Subjects
Exonuclease, Glycerol, Clinical Biochemistry, Pharmaceutical Science, Alpha interferon, Biochemistry, Small hairpin RNA, Ribonucleases, Drug Discovery, Sense (molecular biology), Gene silencing, Animals, A-DNA, RNA, Small Interfering, Molecular Biology, Nuclease, biology, Base Sequence, Chemistry, Organic Chemistry, RNA, Interferon-alpha, Snakes, Immunity, Innate, Cell biology, Phosphodiesterase I, biology.protein, Molecular Medicine, Nucleic Acid Conformation, RNA Interference
Abstract

To improve the nuclease resistance of siRNA while reducing its induction of an innate immune response and maintaining its biological activity for possible therapeutic application, we designed and synthesized a series of double short hairpin RNAs (dshRNAs). Each dshRNA consisted of two identical short hairpin RNAs (shRNAs) linked at their 3' ends by glycerol. The dshRNAs were synthesized on a glycerol-derivatized solid support from amidites with 2-cyanoethoxymethyl (CEM) as the 2'-hydroxyl protecting group. Synthesis was carried out in a single run on a DNA/RNA synthesizer, without the need for enzymatic ligation. The dshRNAs showed structure-dependent gene-silencing activity at the protein level, and dshRNAs in which the 3' end of the two sense regions were linked showed especially high activity. Inclusion of 2'-O-methyluridine residues in the loop region was associated with 1.6- to 2.4-fold lower induction of interferon-α than was siRNA, without loss of gene-silencing activity. dshRNA also showed higher exonuclease resistance than siRNA or canonical shRNA. Our studies provide a new approach to gene silencing based on the concept of linking the 3' end of the sense regions of two shRNA molecules to form a double shRNA.

Published
2010

67. Further improvement in reducing superficial contamination in NIRS using double short separation measurements

Author

Robert J. Cooper, David A. Boas, Louis Gagnon, and Meryem A. Yücel

Subjects
Adult, Male, Materials science, Cognitive Neuroscience, Noise reduction, Movement, Separation (statistics), Signal, Article, Fingers, Hemoglobins, Interference (communication), Image Processing, Computer-Assisted, Humans, Computer Simulation, Spectroscopy, Near-Infrared, Noise (signal processing), Functional Neuroimaging, Detector, Near-infrared spectroscopy, Oxygen, Neurology, Cerebrovascular Circulation, Data Interpretation, Statistical, Female, Optode, Artifacts, Neuroscience, Algorithms, Biomedical engineering
Abstract

Near-Infrared Spectroscopy (NIRS) allows the recovery of the evoked hemodynamic response to brain activation. In adult human populations, the NIRS signal is strongly contaminated by systemic interference occurring in the superficial layers of the head. An approach to overcome this difficulty is to use additional NIRS measurements with short optode separations to measure the systemic hemodynamic fluctuations occurring in the superficial layers. These measurements can then be used as regressors in the post-experiment analysis to remove the systemic contamination and isolate the brain signal. In our previous work, we showed that the systemic interference measured in NIRS is heterogeneous across the surface of the scalp. As a consequence, the short separation measurement used in the regression procedure must be located close to the standard NIRS channel from which the evoked hemodynamic response of the brain is to be recovered. Here, we demonstrate that using two short separation measurements, one at the source optode and one at the detector optode, further increases the performance of the short separation regression method compared to using a single short separation measurement. While a single short separation channel produces an average reduction in noise of 33% for HbO, using a short separation channel at both source and detector reduces noise by 59% compared to the standard method using a general linear model (GLM) without short separation. For HbR, noise reduction of 3% is achieved using a single short separation and this number goes to 47% when two short separations are used. Our work emphasizes the importance of integrating short separation measurements both at the source and at the detector optode of the standard channels from which the hemodynamic response is to be recovered. While the implementation of short separation sources presents some difficulties experimentally, the improvement in noise reduction is significant enough to justify the practical challenges.

Published
2012

68. A Double Short Pulse High-Voltage Power-Supply Based On DSP

Author

Wu Yan, Liang Ping, Xu Dapeng, and Li Guofeng

Subjects
Engineering, Power supply rejection ratio, Switched-mode power supply, business.industry, Pulse-amplitude modulation, Rise time, Electrical engineering, High voltage, Energy consumption, Dielectric barrier discharge, business, Voltage
Abstract

Publisher Summary With the pollution becoming gradually severe, the quality of water deteriorates badly. So, traditional ways of wastewater treatment are being challenged. Recently many researchers paid attention to a way of wastewater treatment by high-voltage discharge in water. Single-pole short pulse and AC high-voltage power supply are most commonly used for generating this kind of discharge. But there are no reported research results of double short pulse high-voltage power supply. The chapter explains a design of a double short pulse high-voltage power supply system, which can output high-peak voltage, short voltage rise time, and high frequency. Mostly importantly, it can be applied on dielectric barrier discharge (DBD) wastewater treatment reactor to decrease energy consumption. The power supply system is composed of a positive and a negative DC high-voltage power supply and a rotating spark-gap switch (RSGS). The RSGS is used to control charge and discharge of pulse forming capacitances. The DC high-voltage power supply employs full-bridge inversion techniques and LCC resonant techniques to realize miniaturization. DSP is the controlling core of the whole power supply system, which regulates pulse amplitude and pulse frequency of power supply, based on the feedback information of interior parameter of the load. This power supply system is applied to discharge in water for dye wastewater treatment.

Published
2004
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98. A promising system of mixed single- and double-short-tailed PEO ether phosphate esters: phase behavior and vesicle formation

Author

Jingcheng Hao, Heinz Hoffmann, and Zaiwu Yuan

Subjects
Ether, Micelle, Biomaterials, chemistry.chemical_compound, Surface-Active Agents, Colloid and Surface Chemistry, Pulmonary surfactant, Bromide, Phase (matter), Organic chemistry, Surface Tension, Sodium dodecyl sulfate, Particle Size, Micelles, Aqueous solution, Molecular Structure, Vesicle, technology, industry, and agriculture, Water, Esters, Organophosphates, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Solutions, chemistry, Nuclear chemistry
Abstract

Acidic surfactants, single- and bi-2-methylheptanol polyethenoxy ether phosphate esters, H2PO3(OCH2CH2)nOCH2CH2CH2CH2CH2CH(CH3)2 (u-MHPEPE) and HPO3[(OCH2CH2)nOCH2CH2CH2CH2CH2CH(CH3)2]2 (d-MHPEPE), where n approximately 4, were synthesized. Phase behavior of u- and d-MHPEPE (u- and d-MHPEPE mixtures were abbreviated as MHPEPE) mixtures in aqueous solutions and vesicle formation were determined. Surface tension measurements showed that u-MHPEPE and MHPEPE have low surface tensions at critical micelle concentrations. gamma(cmc)=29.0 mNm(-1) and cmc=16.0 mmolL(-1) for u-MHPEPE, MHPEPE has two transition points suggesting the mixtures of u- and d-MHPEPE with gamma(cmc1)=30.5 mNm(-1) and cmc1=4.0 mmolL(-1), and gamma(cmc2)=27.3 mNm(-1) and cmc2=42.0 mmolL(-1). These values, specific gamma(cmc), are much lower than those of traditionally cationic or anionic surfactants such as cetyltrimethylammonium bromide (CTAB, gamma(cmc)=37.1 mNm(-1) at cmc=0.92 mmolL(-1)) and sodium dodecyl sulfate (SDS, gamma(cmc)=39.0 mNm(-1) at cmc=8.1 mmolL(-1)). Rich phase behavior was observed with increasing MHPEPE concentration, an isotropic L(1)-phase (micelle solution), an unstable emulsion-region (with time, the samples separate into two-phase), a transparently bluish and birefringent Lalpha-phase up to 200 mmol L(-1) with unilamellar and multilamellar vesicles. These unilamellar and multilamellar vesicles were demonstrated by using staining transmission electron microscopy (staining-TEM), which were compared to freeze-fracture TEM (FF-TEM). The vesicle-phase is stable for at least 1 year. Vesicle formation possibly could be explained in harmonization of the hydrophobic force of acidic surfactant tails, the hydrogen bonding (H-bonding) and the electrostatic interaction among polar headgroups of PEO ether phosphate ester. Phase transition from the flow birefringent unilamellar vesicles induced by addition of HCl, NaCl, NaOH, and increasing temperature has been observed. Surprisingly, for u-MHPEPE or d-MHPEPE in water, we just observed L1-phase (micelle solution) with increasing u-MHPEPE or d-MHPEPE concentration.

Published
2006

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