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While it is widely understood that criminal miscreants are subverting large numbers of Internet-connected computers (e.g., for bots, spyware, SPAM forwarding), it is less well appreciated that Internet routers are also being actively targeted and compromised. Indeed, due to its central role in end-to-end communication, a compromised router can be leveraged to empower a wide range of direct attacks including eavesdropping, man-in-the-middle subterfuge, and denial of service. In response, a range or specialized anomaly detection protocols has been proposed to detect misbehaving packet forwarding between routers. This article provides a general framework for understanding the design space of this work and reviews the capabilities of various detection protocols. 相似文献
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N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine (NO-NTA) is a product of model browning system generated in the presence of sodium nitrite. The chemical structure of this compound has been confirmed by UV, mass and nuclear magnetic resonance, and infrared spectroscopy in our previous study. A two-stage transformation protocol was used to chemically transform the mouse embryo fibroblasts C3H10T1/2 cells. To initiate transformation, the cells were treated with benzo[a]pyrene (BaP) (0.1 mg/ml), and NO-NTA (0.01, 0.1 and 1 mg/ml) was employed subsequently to complete the transformation process. Malignant transformed foci were formed in BaP-initiated and NO-NTA promoted C3H10T1/2 cells after 8 wk. Cells treated with NO-NTA alone failed to induce transformation. However, cells initiated with BaP and promoted by cells initiated with BaP and promoted by NO-NTA demonstrated oncogenic properties. Cell lines transformed with NO-NTA-transformed colonies exhibited enhanced growth rate, anchorage independence and tumorigenicity in animals relative to parent cells. These results indicate that NO-NTA is a new tumour promoter and may induce tumour promotion by two-stage oncogenesis. Further studies on the mechanism of action of NO-NTA are now in progress. 相似文献
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JT Weststrate WC Hop AG Aalbers AW Vreeling HA Bruining 《Canadian Metallurgical Quarterly》1998,24(8):815-820
OBJECTIVE: To evaluate whether the Waterlow pressure sore risk (PSR) scale has prognostic significance for intensive care patients. DESIGN: A prospective study. SETTING: The surgical intensive care unit (ICU) of the University Hospital Rotterdam. PATIENTS: Data were evaluated from 594 patients who had been admitted to the ICU during the year 1994. METHODS AND RESULTS: Each patient was assessed daily with respect to their Waterlow PSR score and the development of pressure sores in the sacral region. Actuarial statistical methods were used to analyse the predictive value of the risk score. When a patient had a Waterlow PSR score > 25 on admission, the risk of developing a pressure sore was significantly increased compared to patients with a PSR score < 25. After admission, the daily Waterlow PSR scores obtained were significantly associated with the risk of developing a pressure sore. For each additional point this risk increased by 23% (95% confidence interval 17 to 28%). CONCLUSIONS: The Waterlow PSR scale provides the medical and nursing staff at an early stage with reliable information about the risk patients have in developing a pressure sore. 相似文献
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AK Akerberg HG Liljeberg YE Granfeldt AW Drews IM Bj-orck 《Canadian Metallurgical Quarterly》1998,128(3):651-660
The purpose of this work was to develop a method for measurement of the major forms of resistant starch (RS) in foods. The analytical procedure was chosen to mimic physiologic conditions, and included chewing as a prestep before incubation with pepsin, pancreatin and amyloglucosidase. The undigestible polysaccharides, including RS, were recovered by ethanol precipitation and subsequent filtration. RS was analyzed as total starch in the filter residue. The residues were also used for gravimetric determination of dietary fiber after correcting for remaining protein, ash and RS. The potentially available starch fraction was determined from analysis of glucose in the filtrate. The foods included were prepared to resemble products for which RS figures were available from in vivo measurements, and/or from analysis with other current in vitro methods. For six of these foods, and for three additional starchy materials, RS figures were compared with in vivo and/or in vitro data for identical products. The pooled standard deviation for the suggested RS method was 2.9%. A high correlation was obtained with in vivo figures from the literature for 19 realistic foods (r = 0.97; y = 0.77x + 0.45). After correction for RS, dietary fiber figures corresponded well with conventional gravimetric dietary fiber analysis for 14 starchy foods (r = 0.97). It is concluded that the procedure described here provides a convenient way to estimate RS content of realistic foods, allowing parallel determination of the potentially available starch fraction and dietary fiber. 相似文献
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Bone marrow from mature goats and sheep was cultured in plasma clots, and three erythropoietin (ESF)-dependent responses-growth (colony formation), differentiation (globin production), and initiation of hemoglobin C (alpha2beta2C) synthesis--were quantitated. ESF concentrations below 0.01 U/ml supported colony growth and adult hemoglobin production in cultures of goat marrow, while maximal hemoglobin C synthesis (70%), as measured between 72 and 96 h in culture, required a 100-fold higher ESF concentration. Sheep marrow was cultured in a medium enriched to enhance growth and to permit complete maturation of colonies. These colonies active in hemoglobin synthesis between 24 and 96 h produced mainly adult hemoglobin, and only between 96 and 120 h did sheep colonies develop which produced mainly hemoglobin C (up to 70%). A similar heterogeneity may exist among goat colonies. Thus, when goat bone marrow was fractionated by unit gravity sedimentation, more hemoglobin C synthesis was observed in colonies derived from cells of intermediate sedimentation velocity than in colonies derived from the most rapidly sedimenting cells. Brief exposure of sheep (in vivo) and goat (in vitro) bone marrow to a high ESF concentration committed precursor cells to the generation of colonies which, even at low ESF concentration, produced hemoglobin C. Committment to hemoglobin phenotype appears to be an early and probably irreversible event in the development of an erythroid cell. 相似文献
89.
The findings of intracellular light-reflecting droplets and clotted mitoses after incubation of Walker and HeLa cells, human lymphocytes and rat fibroblasts with the synthetic amino steroid, 2beta, 16beta-dipiperidino-5alpha-androstane-3-alpha,17beta-diol dipivalate (DAP) were examined in detail. An interaction of DAP with the cellular membranes in all stages of cell life, with the exception of the Go-phase, is postulated. 相似文献
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