3,568 research outputs found

    Accelerating ID-based Encryption based on Trapdoor DL using Pre-computation

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    The existing identity-based encryption (IBE) schemes based on pairings require pairing computations in encryption or decryption algorithm and it is a burden to each entity which has restricted computing resources in mobile computing environments. An IBE scheme (MY-IBE) based on a trapdoor DL group for RSA setting is one of good alternatives for applying to mobile computing environments. However, it has a drawback for practical use, that the key generation algorithm spends a long time for generating a user\u27s private key since the key generation center has to solve a discrete logarithm problem. In this paper, we suggest a method to reduce the key generation time of the MY-IBE scheme, applying modified Pollard rho algorithm using significant pre-computation (mPAP). We also provide a rigorous analysis of the mPAP for more precise estimation of the key generation time and consider the parallelization and applying the tag tracing technique to reduce the wall-clock running time of the key generation algorithm. Finally, we give a parameter setup method for an efficient key generation algorithm and estimate key generation time for practical parameters from our theoretical analysis and experimental results on small parameters. Our estimation shows that it takes about two minutes using pre-computation for about 50 days with 27 GB storage to generate one user\u27s private key using the parallelized mPAP enhanced by the tag tracing technique with 100 processors

    Inhibitory Effect of Inflexinol on Nitric Oxide Generation and iNOS Expression via Inhibition of NF-κB Activation

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    Inflexinol, an ent-kaurane diterpenoid, was isolated from the leaves of Isodon excisus. Many diterpenoids isolated from the genus Isodon (Labiatae) have antitumor and antiinflammatory activities. We investigated the antiinflammatory effect of inflexinol in RAW 264.7 cells and astrocytes. As a result, we found that inflexinol (1, 5, 10 μM) suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 cells and astrocytes. Consistent with the inhibitory effect on iNOS and COX-2 expression, inflexinol also inhibited transcriptional and DNA binding activity of NF-κB via inhibition of IκB degradation as well as p50 and p65 translocation into nucleus. These results suggest that inflexinol inhibits iNOS and COX-2 expression through inhibition of NF-κB activation, thereby inhibits generation of inflammatory mediators in RAW 264.7 cells and astrocytes, and may be useful for treatment of inflammatory diseases

    A Single-Center, Randomized Double-Blind Placebo-Controlled Study Evaluating the Effects of Poly-Gamma-Glutamate on Human NK Cell Activity after an 8-Week Oral Administration in Healthy Volunteers

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    A randomized double-blind placebo-controlled immunity study involving 99 healthy volunteers was performed to investigate the effect of poly-γ-glutamate (γ-PGA) on human natural killer (NK) cell activity in peripheral blood. The volunteers were randomly assigned to one of three groups and orally treated with solutions (25 mL) containing 0 mg (placebo), 250 mg (low dosage), or 500 mg (high dosage) of γ-PGA. Each volunteer took one dose every 12 hours for 8 weeks. Blood samples were drawn before the initial treatment and at the 4th and the 8th weeks of treatment. NK cell activity was assessed by measuring its degranulation, cytokine production, and cytotoxicity against the K562 cell line. Our results revealed that the cytotoxic activities of NK cells from the high-dosage γ-PGA group were significantly higher (P<0.05 for all comparisons) compared to the low dosage and placebo groups at weeks 4 and 8 after the initial treatment. This increase in the NK cell activity among peripheral blood mononuclear cells (PBMCs) of healthy individuals was also confirmed in vitro (as assessed by the degranulation and cytokine production). These results suggest that the oral administration of γ-PGA induces a cell-mediated immunity by increasing the NK cell activity in humans

    A Case of Severe Anemia by Necator americanus Infection in Korea

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    This report describes clinical and parasitological findings of an 82-yr-old female patient who lived in a local rural village and suffered from severe chronic anemia for several years. She was transferred to the National Police Hospital in Seoul for management of severe dyspnea and dizziness. At admission, she showed symptoms or signs of severe anemia. Gastroduodenoscopy observed hyperemic mucosa of the duodenum and discovered numerous moving roundworms on the mucosa. Endoscopy isolated seven of them, which were identified as Necator americanus by characteristic morphology of cutting plates in the buccal cavity. The patient was treated with albendazole and supportive measures for anemia, and her physical condition much improved. This case suggests the possibility that hookworm N. americanus is still transmitted in a remote local mountainous area in Korea

    Transcriptional changes in the developing rice seeds under salt stress suggest targets for manipulating seed quality

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    Global sea-level rise, the effect of climate change, poses a serious threat to rice production owing to saltwater intrusion and the accompanying increase in salt concentration. The reclaimed lands, comprising 22.1% of rice production in Korea, now face the crisis of global sea-level rise and a continuous increase in salt concentration. Here, we investigated the relationship between the decrease in seed quality and the transcriptional changes that occur in the developing rice seeds under salt stress. Compared to cultivation on normal land, the japonica rice cultivar, Samgwang, grown on reclaimed land showed a greatly increased accumulation of minerals, including sodium, magnesium, potassium, and sulfur, in seeds and a reduced yield, delayed heading, decreased thousand grain weight, and decreased palatability and amylose content. Samgwang showed phenotypical sensitivity to salt stress in the developing seeds. Using RNA-seq technology, we therefore carried out a comparative transcriptome analysis of the developing seeds grown on reclaimed and normal lands. In the biological process category, gene ontology enrichment analysis revealed that the upregulated genes were closely associated with the metabolism of biomolecules, including amino acids, carboxylic acid, lignin, trehalose, polysaccharide, and chitin, and to stress responses. MapMan analysis revealed the involvement of upregulated genes in the biosynthetic pathways of abscisic acid and melatonin and the relationship of trehalose, raffinose, and maltose with osmotic stress. Interestingly, many seed storage protein genes encoding glutelins and prolamins were upregulated in the developing seeds under salt stress, indicating the negative effect of the increase of storage proteins on palatability. Transcription factors upregulated in the developing seeds under salt stress included, in particular, bHLH, MYB, zinc finger, and heat shock factor, which could act as potential targets for the manipulation of seed quality under salt stress. Our study aims to develop a useful reference for elucidating the relationship between seed response mechanisms and decreased seed quality under salt stress, providing potential strategies for the improvement of seed quality under salt stress
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