48 research outputs found

    Targeted delivery of iron oxide nanoparticle-loaded human embryonic stem cell-derived spherical neural masses for treating intracerebral hemorrhage

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    This study evaluated the potential of iron oxide nanoparticle-loaded human embryonic stem cell (ESC)-derived spherical neural masses (SNMs) to improve the transportation of stem cells to the brain, ameliorate brain damage from intracerebral hemorrhage (ICH), and recover the functional status after ICH under an external magnetic field of a magnet attached to a helmet. At 24 h after induction of ICH, rats were randomly separated into three experimental groups: ICH with injection of phosphate-buffered saline (PBS group), ICH with intravenous injection of magnetosome-like ferrimagnetic iron oxide nanocubes (FION)-labeled SNMs (SNMs* group), and ICH with intravenous injection of FION-labeled SNMs followed by three days of external magnetic field exposure for targeted delivery by a magnet-embedded helmet (SNMs*+Helmet group). On day 3 after ICH induction, an increased Prussian blue-stained area and decreased swelling volume were observed in the SNMs*+Helmet group compared with that of the other groups. A significantly decreased recruitment of macrophages and neutrophils and a downregulation of pro-inflammatory cytokines followed by improved neurological function three days after ICH were observed in the SNMs*+Helmet group. Hemispheric atrophy at six weeks after ICH was significantly decreased in the SNMs*+Helmet group compared with that of the PBS group. In conclusion, we have developed a targeted delivery system using FION tagged to stem cells and a magnet-embedded helmet. The targeted delivery of SNMs might have the potential for developing novel therapeutic strategies for ICH.

    Fifteen Years After the Gozan-Dong Glass Fiber Outbreak, Incheon in 1995

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    Objectives: In 1995, an outbreak survey in Gozan-dong concluded that an association between fiberglass exposure in drinking water and cancer outbreak cannot be established. This study follows the subjects from a study in 1995 using a data linkage method to examine whether an association existed. The authors will address the potential benefits and methodological issues following outbreak surveys using data linkage, particularly when informed consent is absent. Methods: This is a follow-up study of 697 (30 exposed) individuals out of the original 888 (31 exposed) participants (78.5%) from 1995 to 2007 assessing the cancer outcomes and deaths of these individuals. The National Cancer Registry (KNCR) and death certificate data were linked using the ID numbers of the participants. The standardized incidence ratio (SIR) and standardized mortality ratio (SMR) from cancers were calculated by the KNCR. Results: The SIR values for all cancer or gastrointestinal cancer (GI) occurrences were the lowest in the exposed group (SIR, 0.73; 95% CI, 0.10 to 5.21; 0.00 for GI), while the two control groups (control 1: external, control 2: internal) showed slight increases in their SIR values (SIR, 1.18 and 1.27 for all cancers; 1.62 and 1.46 for GI). All lacked statistical significance. All-cause mortality levels for the three groups showed the same pattern (SMR 0.37, 1.29, and 1.11). Conclusions: This study did not refute a finding of non-association with a 13-year follow-up. Considering that many outbreak surveys are associated with a small sample size and a cross-sectional design, follow-up studies that utilize data linkage should become standard procedure.OAIID:oai:osos.snu.ac.kr:snu2011-01/102/0000040632/15SEQ:15PERF_CD:SNU2011-01EVAL_ITEM_CD:102USER_ID:0000040632ADJUST_YN:YEMP_ID:A077602DEPT_CD:902CITE_RATE:0FILENAME:fifteen years after the gozan-dong glass fiber outbreak, incheon in 1995..pdfDEPT_NM:보건학과CONFIRM:

    Mesenchymal stem cell-derived magnetic extracellular nanovesicles for targeting and treatment of ischemic stroke

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    Exosomes and extracellular nanovesicles (NV) derived from mesenchymal stem cells (MSC) may be used for the treatment of ischemic stroke owing to their multifaceted therapeutic benefits that include the induction of angiogenesis, anti-apoptosis, and anti-inflammation. However, the most serious drawback of using exosomes and NV for ischemic stroke is the poor targeting on the ischemic lesion of brain after systemic administration, thereby yielding a poor therapeutic outcome. In this study, we show that magnetic NV (MNV) derived from iron oxide nanoparticles (IONP)-harboring MSC can drastically improve the ischemic-lesion targeting and the therapeutic outcome. Because IONP stimulated expressions of therapeutic growth factors in the MSC, MNV contained greater amounts of those therapeutic molecules compared to NV derived from naive MSC. Following the systemic injection of MNV into transient middle-cerebral-artery-occlusion (MCAO)-induced rats, the magnetic navigation increased the MNV localization to the ischemic lesion by 5.1 times. The MNV injection and subsequent magnetic navigation promoted the anti-inflammatory response, angiogenesis, and anti-apoptosis in the ischemic brain lesion, thereby yielding a considerably decreased infarction volume and improved motor function. Overall, the proposed MNV approach may overcome the major drawback of the conventional MSC-exosome therapy or NV therapy for the treatment of ischemic stroke.

    Porous zeolitic imidazolate frameworks assembled with highly-flattened tetrahedral copper(ii) centres and 2-nitroimidazolates

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    Cu(ii)-based zeolitic imidazolates (Cu-ZIFs), Cu-ZIF-gis and -rho, formulated as Cu(nIm)(2) (nIm = 2-nitroimidazolate) have highly-flattened tetrahedral coordination geometry. Cu-ZIF-gis has 2.4 & ANGS; cylindrical pores that can adsorb H-2 gas, and Cu-ZIF-rho has 19.8 & ANGS; cages with a BET surface area of 1320 m(2) g(-1)

    RansomBlocker: A low-overhead ransomware-proof SSD

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    © 2019 Association for Computing Machinery.We present a low-overhead ransomware-proof SSD, called RansomBlocker (RBlocker). RBlocker provides 100% full protections against all possible ransomware attacks by delaying every data deletion until no attack is guaranteed. To reduce storage overheads of the delayed deletion, RBlocker employs a time-out based backup policy. Based on the fact that ransomware must store encrypted version of target files, early deletions of obsolete data are allowed if no encrypted write was detected for a short interval. Otherwise, RBlocker keeps the data for an interval long enough to guarantee no attack condition. For an accurate in-line detection of encrypted writes, we leverages entropy- and CNN-based detectors in an integrated fashion. Our experimental results show that RBlocker can defend all types of ransomware attacks with negligible overheads.N

    Effect of Black Pepper (<i>Piper nigrum</i>) Extract on Caffeine-Induced Sleep Disruption and Excitation in Mice

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    Sleep is one of the most essential factors required to maintain good health. However, the global prevalence of insomnia is increasing, and caffeine intake is a major trigger. The objective of this study was to investigate the inhibitory effect of black pepper, Piper nigrum extract (PE), on caffeine-induced sleep disruption and excitation in mice. Caffeine significantly decreased sleep duration in the pentobarbital-induced sleep test. It also resulted in a significant increase in sleep onset and a decrease in non-rapid eye movement sleep. Moreover, in an open-field test, caffeine-treated mice exhibited a significantly increased time in the center zone and total distance traveled. However, the co-administration of caffeine and PE did not result in similar arousal activities. Thus, our results suggest that PE can be used as a potential therapeutic agent to treat sleep problems and excitatory status associated with caffeine intake

    Comparative Design Study of HTS Synchronous Motor With Inner and Outer Rotor Type Based on Multi-Objective Optimization

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    In this paper, we report a design comparison between the inner and the outer rotor type for a partial high temperature superconductor (HTS) synchronous motor based on a multi-objective optimization. The partial HTS synchronous motors applied with no-insulation and multi-width winding technique are optimized by considering three characteristics; specific power (power per mass), power density (power per volume), and HTS tape consumption, simultaneously. The performance of each design is evaluated through the electromagnetic finite element method. Finally, the results obtained by optimization are compared between the inner and the outer rotor type.N

    Harmonic Current Reduction Method of Hand-Held Resonant Magnetic Field Charger (HH-RMFC) for Electric Vehicle

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    The hand-held resonant magnetic field charger (HH-RMFC) is a convenient equipment of charging the batteries without any electrical contact. Due to high coupling coefficient of HH-RMFC, the single phase power inverter with square wave encounter relatively small reactance at its harmonic frequencies. Thus, the current flowing through the Tx and Rx windings can be distorted. The distorted current with large amount of harmonics may act as magnetic near field noise to the adjacent sensitive electronic devices such as sensors, controller and communication devices in electric vehicles (EVs). Moreover, the current harmonics have the effect of increasing losses and thermal stress in power system. In this paper, a reduction method of the harmonic currents in HH-RMFC is proposed. The circuit simulation results show that the harmonic currents flowing through Tx and Rx windings in HH-RMFC can significantly be reduced by applying the proposed method. The circuit simulation results show that proposed method can reduces THD of Tx current and Rx current by 15.64 % and 14.11 %, respectively
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