11,890 research outputs found

    The changing immunology of organ transplantation

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    The engrafted organ becomes a chimera as the recipient's leukocytes station themselves in the transplant. Remarkably, the recipient becomes chimeric as well, in a reverse migration involving immune cells from the graft. Interactions between donor and recipient cells are tolerogenic-a process with implications for the goal of graft acceptance with minimal immunosuppression

    An improved wavelet analysis method for detecting DDoS attacks

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    Wavelet Analysis method is considered as one of the most efficient methods for detecting DDoS attacks. However, during the peak data communication hours with a large amount of data transactions, this method is required to collect too many samples that will greatly increase the computational complexity. Therefore, the real-time response time as well as the accuracy of attack detection becomes very low. To address the above problem, we propose a new DDoS detection method called Modified Wavelet Analysis method which is based on the existing Isomap algorithm and wavelet analysis. In the paper, we present our new model and algorithm for detecting DDoS attacks and demonstrate the reasons of why we enlarge the Hurst's value of the self-similarity in our new approach. Finally we present an experimental evaluation to demonstrate that the proposed method is more efficient than the other traditional methods based on wavelet analysis. © 2010 IEEE

    The behavior of two-way reinfoced concrete slabs externally strengthened with steel plate to subject patch load

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    2001-2002 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Stimulation of artemisinin biosynthesis in Artemisia annua hairy roots by oligogalacturonides

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    The different fractions of oligogalacturonides (OGA) from polygalacturonic acid by pectinase hydrolysate have been partially purified using column chromatography of Sephadex G-10. The isolated fraction OGA2 (degree of polymerization, DP = 4.57) was found to stimulate the accumulation ofartemisinin in Artemisia annua hairy roots. When hairy roots of 16-day old cultures were exposed to the OGA elicitor (60 g/mL) for 4 days, the maximum production of artemisinin reached 11.3 mg/L, a 55.2% increase over the control. OGA could induce H2O2 production in hairy root culture as one of early defense events. Moreover, the OGA-induced reactive oxygen species (ROS) were involved in stimulating the artemisinin biosynthesis in the hairy roots. This is the first report on the stimulation of artemisinin production in hairy roots by an oligogalacturonide elicitor

    Genetic diversity and population structure of Caragana microphylla Lam. based on analysis of inter-simple sequence repeat markers

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    Caragana microphylla Lam. is a long-lived shrub species in the semi-arid, arid and desert regions. To determine the genetic diversity and population structure of C. microphylla Lam., 17 wild populations from the central and eastern part of Inner Mongolia were analyzed by inter-simple sequence repeat. 18 primers  produced 296 bands across a total of 510 individuals. A high percentage of polymorphic loci was observed at species level (PPB = 81.4%). Based on analysis of molecular variance, 74.99% of the genetic variation of C. microphylla Lam. was found within population, 7% difference between regions and 15.2% among collection  sites within regions. Cluster analyses showed that 17 populations are most arranged in the same cluster by  geographic location. An indirect estimate of the GST-derived Nm value (Nm = 1.8921) indicate that gene flow is high among 17 populations. No significant correlation (r2 = 0.13) between genetic and geographic distance was detected. Results of this study suggest that C. microphylla Lam. has a high genetic variability and potential as a source of variation for breeding programs.Key words: Inter-simple sequence repeat (ISSR), Caragana microphylla Lam., genetic structure

    Migration patterns and winter population dynamics of rice planthoppers in Indochina: New perspectives from field surveys and atmospheric trajectories

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    This is the author accepted manuscript. The final version is available from Elsevier Masson via the DOI in this record.Rice planthoppers (RPH) are the most serious insect pests of rice production in East Asia, frequently out-breaking in China, Korea and Japan each summer. They are unable to overwinter in temperate East Asia, and summer populations arise anew each year via northward spring migration from south-east Asia. The annual migration cycle is generally believed to be a closed loop with mass returns to south-east Asia in the autumn, but this leg of the journey and the overwintering dynamics are much less studied than the spring immigrations. Previous studies have indicated that the north-central Vietnam (NCV) region is a key location for both the spring colonisation of China and for receiving return migrants from southern China each autumn. However, NCV experiences a three-month rice-free fallow period during mid-winter, and so it cannot be the principal over-wintering region for RPH populations. In this study, the continental-scale migration patterns of RPH in East Asia were explored using data from light trap catches, field surveys and atmospheric trajectory simulations. Our results confirmed that large numbers of return migrants arrive in NCV from southern China each autumn, but that they are unable to survive there over winter. The NCV region is recolonised in the early-spring (mid-February to mid-March) of each year by migrants from winter rice-growing regions in north-east Thailand, southern Laos and south-central coastal Vietnam, which are transported on favourable high-altitude synoptic winds. The following generation initiates the colonisation of East Asia from a large source population in NCV. Our results provide a new perspective on RPH migration patterns and over-wintering dynamics in East Asia, which is governed by crop production, environmental conditions and synoptic wind patterns at a continental scale.National Natural Science Foundation of China (NSFC)Natural Science Foundation of Jiangsu ProvinceBiotechnology and Biological Sciences Research Council (BBSRC)Science and Technology Facilities Council (STFC

    Reduction of Retinal Thickness Ipsilateral to Hippocampal Sclerosis in Epilepsy

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    OBJECTIVES: Reductions in the peripapillary retinal nerve fiber layer (pRNFL) have been reported in epilepsy, namely in drug-resistant people. Hippocampal sclerosis (HS) is the most frequent cause of drug-resistant epilepsy in tertiary care centers. We aimed to evaluate the likelihood and characteristic of RNFL loss in individuals with epilepsy having HS. METHODS: Fifty-five adults diagnosed with unilateral HS (mean age of 25 years; 42 female) by magnetic resonance imaging were included in this observational cross-sectional study, 58 age-matched individuals with epilepsy with no detectable structural brain abnormality were included as non-HS, and 55 people without neurological diseases were included as healthy controls. pRNFL of both eyes was measured by optical coherence tomography (OCT). In each individual disease related information was recorded. RESULTS: Among the 55 individuals with unilateral HS, one (1.82%) and ten (18.18%) had significant or borderline abnormal thinning of the pRNFL of the ipsilateral eye to the HS. The average pRNFL ipsilateral to the side of HS was significantly thinner than people with epilepsy non-HS (p = 0.013) and healthy controls (p = 0.000), especially in the inferior quadrants. Only age was significantly correlated with the average and inferior quadrant pRNFL thickness of the ipsilateral eye to the HS (R = −0.286, p = 0.035; R = −0.353, p = 0.008 respectively). CONCLUSION: These preliminary findings suggest that retinal abnormalities associated with HS may have a specific pattern. Further studies need to confirm this finding and to unravel the underlying mechanism
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